JP2019106311A - Manufacturing method for electrode sheet - Google Patents

Abstract

To provide a manufacturing method for an electrode sheet hardly having a film deposition defect (film deposition fault).SOLUTION: As for a manufacturing method for electrode sheet in which an electrode sheet 19 having an electrode mixture layer 18 on a surface of a current collector foil 7 is manufactured, in a roll molding process S2, F1<F2 holds for an average value F1 (kPa) of liquid crosslinking force between a wet granulation body 16 included in an electrode mixture 6 and a surface 1b of a first roll 1 and an average value F2 (kPa) of liquid crosslinking force between the wet granulation body 16 included in the electrode mixture 6 and a surface 2b of a second roll 2, when the electrode mixture 6 passes through a gap between the first roll 1 and second roll 2.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a method of manufacturing an electrode sheet that constitutes a battery. Specifically, the present invention relates to a method for producing an electrode sheet having a structure in which an electrode mixture layer is formed on the surface of a current collector foil.

  BACKGROUND Conventionally, an electrode sheet having a structure in which an electrode mixture layer is formed on the surface of a current collector foil is known as an electrode sheet (positive electrode sheet or negative electrode sheet). As a method of manufacturing an electrode sheet having such a structure, for example, a method disclosed in Patent Document 1 is known. Specifically, first, an electrode mixture including a plurality of wet granules obtained by granulating a mixture of an electrode active material, a binder and a solvent is prepared. Then, the electrode mixture is passed through a gap between a pair of opposing rolls to form a film, and the film-like electrode mixture is attached onto the surface of the current collector foil.

JP, 2013-77560, A

  More specifically, in the roll forming step, the electrode mixture is passed through a gap between a pair of rolls consisting of a second roll for transferring the electrode mixture to the current collector foil and a first roll opposite thereto. As a result, the electrode mixture is formed into a film, and the film-formed electrode mixture is attached to the second roll. Thereafter, in the transfer step, the film-like electrode mixture adhering to the second roll is transferred (adhered) onto the surface of the current collector foil. Thereafter, in the electrode mixture layer forming step, the film-like electrode mixture deposited on the surface of the current collector foil is dried to form an electrode mixture layer on the surface of the current collector foil, thereby forming an electrode sheet. Make.

  In Patent Document 1, the circumferential speed of the second roll is made faster than the circumferential speed of the first roll. Thereby, when the electrode mixture (wet granulated body) compressed into a film shape between the first roll and the second roll passes the gap between the first roll and the second roll, The contact area (liquid crosslinking area) with the second roll is larger than the contact area (liquid crosslinking area) with the roll. Thereby, when passing through the gap between the first roll and the second roll, the film-like electrode mixture (wet granulated body) adheres (is carried) on the surface of the second roll.

  By the way, when producing the electrode mixture which consists of a wet granulated body, it is difficult to disperse | distribute a solvent uniformly over the whole electrode mixture. For this reason, in the electrode mixture, a large variation may occur in the solid fraction (in other words, the solvent content) of the plurality of wet granules constituting the electrode mixture. That is, the wet granules having a high solid fraction (in other words, low solvent content) and the wet granules having a low solid fraction (in other words, high solvent content) are included in the electrode mixture. Sometimes mixed up with Moreover, also in each wet granulated body which comprises an electrode compound material, a big variation might arise in a solid fraction (in other words, solvent content rate). That is, in one wet granulated body, a portion having a high solid fraction (in other words, a low solvent content) and a portion having a low solid fraction (in other words, a high solvent content) are mixed I had something to do.

  In the electrode mixture, when the electrode mixture made of such wet granules passes through the gap between the oppositely rotating first roll and the second roll having a higher peripheral speed in the roll forming step, A part of the wet granules may adhere to the surface of the first roll without adhering to the surface of the second roll. For this reason, a hole may be formed in the film of the electrode mixture attached to the surface of the second roll (or the thickness of the film may become extremely thin in part). As a result, in the transfer step, the film of the electrode mixture transferred from the surface of the second roll to the surface of the current collector foil is in a state in which holes are formed (or the film thickness becomes extremely thin partially). ) A film formation failure (film formation defect) may occur. In the case where the film formation defect (film formation defect) is large, the electrode sheet constituting the battery may not be used properly.

  The reason why such a defect occurs is considered as follows. Specifically, for example, in a wet granulated body, a portion having a high solid fraction (in other words, a low solvent content) and a portion having a low solid fraction (in other words, a high solvent content) And when the wet granulated material passes through the gap between the first and second rolls rotating in the opposite direction, the solid fraction is high (in other words, the solvent content of When the low (low) site contacts the surface of the second roll and the low solid fraction (in other words, high solvent content) site contacts the surface of the first roll, The liquid crosslinking power between the first roll and the surface of the first roll is greater than the liquid crosslinking power between the wet granules and the surface of the second roll.

  For this reason, when the wet granulate passes through the gap between the oppositely rotating first roll and the second roll, it does not adhere to the surface of the second roll but adheres to the surface of the first roll There are times when For this reason, in the film of the electrode mixture attached to the surface of the second roll, a hole may be formed at the site where the wet granulated body has been removed (or the thickness of the membrane becomes extremely thin at the site). is there. As a result, even in the film of the electrode mixture transferred from the surface of the second roll onto the surface of the current collector foil in the transfer step, the holes are open at the relevant site (or the thickness of the film at the relevant site) Is extremely thin, and film formation defects (film formation defects) are considered to occur.

  The present invention has been made in view of the present situation, and it is an object of the present invention to provide a method of manufacturing an electrode sheet which is less likely to cause film formation defects (film formation defects).

  According to one aspect of the present invention, an electrode mixture composed of a plurality of wet granules obtained by granulating a mixture of an electrode active material, a binder and a solvent is divided into a first roll which rotates in the opposite direction and a periphery of the first roll. A roll forming step in which the electrode mixture is compressed into a film while being passed through a gap with a second roller having a high speed, and the electrode mixture made into a film is attached to the surface of the second roller; A transfer step of transferring the film-like electrode mixture adhering to the surface of the second roll onto the surface of the current collector foil, and the film-like electrode mixture transferred onto the surface of the current collector foil An electrode mixture layer forming step of forming an electrode mixture layer on the surface of the current collector foil by drying the electrode sheet, the electrode sheet having the electrode mixture layer on the surface of the current collector foil In the method of manufacturing an electrode sheet to be manufactured, in the roll forming step, the electrode mixture is used for the first row. An average value F1 (kPa) of liquid crosslinking power between the wet granulated body contained in the electrode mixture and the surface of the first roll when passing through the gap between the second roll and the second roll; It is a manufacturing method of the electrode sheet with which the average value F2 (kPa) of the liquid bridge construction power between the above-mentioned moist granules contained in electrode mixture and the surface of the 2nd roll fulfills the relation of F1 <F2.

  In the above-described manufacturing method, in the roll forming step, when the electrode mixture passes through the gap between the first roll and the second roll, between the wet granulated body contained in the electrode mixture and the surface of the first roll The average value F1 (kPa) of the liquid crosslinking power and the average value F2 (kPa) of the liquid crosslinking power between the wet granulated body contained in the electrode mixture and the surface of the second roll satisfy F1 <F2 Try to meet the relationship. In the above-described manufacturing method, the circumferential speed of the second roll is made faster than the circumferential speed of the first roll in the roll forming step, as in the prior art.

  More specifically, in the electrode mixture, even if variation occurs in the solid fraction (in other words, the solvent content) of the plurality of wet granules constituting the electrode mixture, the electrode In the roll forming process, the electrode mixture is the first roll and the second roll in the roll forming step, even if the solid fraction (in other words, the solvent content) varies in each wet granulated body constituting the mixture. And the average value F1 (kPa) of the liquid crosslinking power between the wet granules contained in the electrode mixture and the surface of the first roll when passing through the gap between The average value F2 (kPa) of the liquid crosslinking force between the particles and the surface of the second roll is made to satisfy the relationship of F1 <F2.

  By doing this, when the wet granulated body contained in the electrode mixture passes through the gap between the first and second rolls rotating in the opposite direction, the relative movement among the first and second rolls is achieved. It becomes easy to adhere to the surface of the 2nd roll with large liquid crosslinking power.

  For example, in a wet granulated body, a site having a high solid fraction (in other words, a low solvent content) and a site having a low solid fraction (in other words, a high solvent content) are mixed When the wet granulated material passes through the gap between the first and second rolls rotating in the opposite direction, the portion with a high solid content (in other words, the portion with a low solvent content) Even when the surface of the second roll contacts the surface of the first roll and the site of low solid content (in other words, the high solvent content) contacts the surface of the first roll, The liquid cross-linking ability between the two is greater than the liquid cross-linking ability between the wet granulate and the surface of the first roll, which makes it possible to adhere the wet granulate to the surface of the second roll .

  Therefore, in the above-mentioned roll forming process, in the film of the electrode mixture adhering to the surface of the second roll, a part of the wet granules contained in the electrode mixture adheres to the surface of the first roll It becomes difficult to produce holes (or an extreme reduction in film thickness). As a result, in the film of the electrode mixture transferred from the surface of the second roll onto the surface of the current collector foil in the later transfer step, it becomes difficult to cause pores (or an extreme reduction in film thickness), Film defects (deposition defects) are less likely to occur.

As described above, the above-described manufacturing method is a method of manufacturing an electrode sheet in which film formation defects (film formation defects) are less likely to occur.
In addition, a wet granulated body refers to a substance (particulate body) in which these are aggregated (bonded) in a state where a solvent is held (absorbed) by particles of a plurality of electrode active materials and a binder.

  Furthermore, in the method of manufacturing an electrode sheet, in the roll forming step, the electrode mixture is removed while the surface of the first roll is dried by blowing air onto the surface of the first roll. It is good to set it as the manufacturing method of an electrode sheet which is made to fill a relation of F1 <F2 by letting it pass through a gap of 1 roll and the 2nd roll.

  In the above-described manufacturing method, in the roll forming step, the surface of the first roll is dried by blowing air on the surface of the first roll, and the electrode mixture (wet granulated body) is made into the first roll and the second roll. To satisfy the relationship of F1 <F2.

  Thus, the amount of water on the surface of the first roll is made smaller than the amount of water on the surface of the second roll by drying the surface of the first roll by blowing air onto the surface of the first roll. it can. In other words, the amount of water on the surface of the second roll can be made larger than the amount of water on the surface of the first roll. Thereby, in the roll forming step, when the electrode mixture passes through the gap between the first roll and the second roll, liquid bridge between the wet granulated body contained in the electrode mixture and the surface of the first roll The average value F1 of force (kPa) and the average value F2 (kPa) of liquid crosslinking force between the wet granulated body contained in the electrode mixture and the surface of the second roll satisfy the relationship of F1 <F2 It will be.

  By doing this, in the roll forming step, when the wet granulated body contained in the electrode mixture passes through the gap between the first and second rolls rotating in the opposite direction, the first roll and the second roll are formed. Of the rolls, the roll easily adheres to the surface of the second roll having a relatively high liquid crosslinking ability. Therefore, in the film of the electrode mixture formed on the surface of the second roll, the holes (or the extreme reduction of the film thickness) hardly occur, and the surface of the second roll also in the transfer step after the roll forming step. From this, it becomes difficult for the holes (or the extreme reduction in film thickness) to occur in the film of the electrode mixture transferred onto the surface of the current collector foil. Therefore, according to the above-described manufacturing method, film formation defects (film formation defects) are less likely to occur.

  Furthermore, in the method of manufacturing the electrode sheet, it is preferable that in the roll forming step, dry air having a dew point of -30 ° C. or less is used as the air sprayed on the surface of the first roll. .

  In the above-described manufacturing method, dry air having a dew point of -30 ° C or less is used as air to be blown to the surface of the first roll in the roll forming step. That is, in the roll forming step, dry air having a dew point of -30 ° C. or less is blown to the surface of the first roll to dry the surface of the first roll while the electrode mixture (wet granulated body) is made the first roll. The relationship between F1 <F2 is satisfied by passing it through the gap between the first and second rolls.

  Thus, the amount of water on the surface of the first roll can be determined by drying the surface of the first roll by blowing dry air having a dew point of −30 ° C. or less onto the surface of the first roll. It can be even less compared to the amount. In other words, the amount of water on the surface of the second roll can be further increased compared to the amount of water on the surface of the first roll. Thereby, the difference between F1 and F2 can be increased. That is, F2 can be made larger than F1.

  In this way, when the wet granulation body contained in the electrode mixture passes through the gap between the first and second rolls rotating in the opposite direction in the roll forming step, the surface of the second roll It becomes easier to adhere. Therefore, in the film of the electrode mixture formed on the surface of the second roll, the holes (or the extreme reduction of the film thickness) are more difficult to occur, and the current collecting foil is also used in the transfer step after the roll forming step. In the film of the electrode mixture transferred onto the surface of the above, it is even more difficult for the holes (or the extreme reduction of the film thickness) to occur. Therefore, according to the above-described manufacturing method, film formation defects (film formation defects) are further less likely to occur.

  Furthermore, in the method of manufacturing an electrode sheet according to any one of the above-described aspects, in the roll forming step, it is preferable that the method be a method of manufacturing an electrode sheet satisfying a relationship of F1 ≦ 2.8 kPa.

  In the above-described manufacturing method, the relationship of F1 ≦ 2.8 kPa is satisfied in the roll forming step. Specifically, for example, in the roll forming step, the surface of the first roll is dried by blowing air onto the surface of the first roll such that F1 ≦ 2.8 kPa. Thus, by reducing the average value F1 (kPa) of the liquid cross-linking ability between the wet granulated body contained in the electrode mixture and the surface of the first roll, it is included in the electrode mixture in the roll forming step. It becomes extremely difficult for the wet granules to adhere to the surface of the first roll. In other words, in the roll forming step, the wet granulated body contained in the electrode mixture is very likely to adhere to the surface of the second roll.

  Therefore, in the film of the electrode mixture formed on the surface of the second roll, the holes (or the extreme reduction of the film thickness) hardly occur, and in the transfer step after the roll forming step, It becomes extremely difficult for the pores (or the extreme reduction of the film thickness) to occur in the film of the electrode mixture transferred onto the surface. Therefore, according to the above-described manufacturing method, film formation defects (film formation defects) hardly occur.

  Furthermore, in the method for manufacturing an electrode sheet according to any one of the above-described aspects, in the roll forming step, the electrode mixture is wetted while the surface of the second roll is wetted by adhering a liquid to the surface of the second roll. It is preferable that the method of manufacturing an electrode sheet satisfies the relationship of F1 <F2 by passing through the gap between the first roll and the second roll.

  In the above-described manufacturing method, in the roll forming step, the electrode composite material (wet granulated body) is formed while the surface of the second roll is wetted (wetted) by depositing liquid on the surface of the second roll. The relationship of F1 <F2 is satisfied by passing through the gap between the 1st roll and the 2nd roll.

  As described above, by moistening the surface of the second roll by depositing liquid on the surface of the second roll, the amount of water on the surface of the second roll is determined by the amount of water on the surface of the first roll. You can also do more. Thereby, in the roll forming step, when the electrode mixture passes through the gap between the first roll and the second roll, liquid bridge between the wet granulated body contained in the electrode mixture and the surface of the first roll The average value F1 of force (kPa) and the average value F2 (kPa) of liquid crosslinking force between the wet granulated body contained in the electrode mixture and the surface of the second roll satisfy the relationship of F1 <F2 It will be.

  By doing this, in the roll forming step, when the wet granulated body contained in the electrode mixture passes through the gap between the first and second rolls rotating in the opposite direction, the first roll and the second roll are formed. Of the rolls, the roll easily adheres to the surface of the second roll having a relatively high liquid crosslinking ability. Therefore, in the film of the electrode mixture formed on the surface of the second roll, the holes (or the extreme reduction of the film thickness) hardly occur, and the surface of the current collector foil also in the transfer step after the roll forming step. Holes (or an extreme decrease in film thickness) are less likely to occur in the film of the electrode mixture transferred to the upper side. Therefore, according to the above-described manufacturing method, film formation defects (film formation defects) are less likely to occur.

  Furthermore, in the method for producing an electrode sheet, in the roll forming step, an electrode using a liquid equivalent to the solvent contained in the wet granulated body as the liquid to be attached to the surface of the second roll. It is good if it is the manufacturing method of a sheet.

  In the above-described manufacturing method, in the roll forming step, a liquid equivalent to the solvent contained in the wet granulated body is used as the liquid to be attached to the surface of the second roll. That is, in the roll forming step, the surface of the second roll is wetted by depositing a liquid equivalent to the solvent contained in the wet granulated body on the surface of the second roll.

  Thus, by using a liquid equivalent to the solvent contained in the wet granulated body as the liquid to be attached to the surface of the second roll, the wet granulated body contained in the electrode mixture and the surface of the second roll The average value F2 (kPa) of the liquid crosslinking power between them can be appropriately increased. Furthermore, even if the liquid adheres to the wet granules, it is preferable because problems such as deterioration of the electrode active material and the binder contained in the wet granules do not occur.

  Furthermore, in the method of manufacturing an electrode sheet according to any one of the above-described aspects, in the roll forming step, the electrode sheet may satisfy the relationship of F2 ≧ 12.4 kPa.

  In the above-described manufacturing method, the relationship of F2 ≧ 12.4 kPa is satisfied in the roll forming step. Specifically, for example, in the roll forming process, the surface of the second roll is wetted by depositing a liquid on the surface of the second roll such that F2 ≧ 12.4 kPa.

  Thus, by increasing the average value F2 (kPa) of the liquid cross-linking ability between the wet granulated body contained in the electrode mixture and the surface of the second roll, it is included in the electrode mixture in the roll forming step. Wet granules are very likely to adhere to the surface of the second roll. Therefore, in the film of the electrode mixture formed on the surface of the second roll, the holes (or the extreme reduction of the film thickness) hardly occur, and in the transfer step after the roll forming step, It becomes extremely difficult for the pores (or the extreme reduction of the film thickness) to occur in the film of the electrode mixture transferred onto the surface. Therefore, according to the above-described manufacturing method, film formation defects (film formation defects) hardly occur.

It is the perspective schematic of the roll film-forming apparatus concerning Example 1, 2. It is the side view schematic of the roll film-forming apparatus. It is the cross-sectional schematic of a negative electrode sheet and a positive electrode sheet. It is a flowchart which shows the flow of the manufacturing method of a negative electrode sheet. It is a subroutine of the flowchart of FIG. It is a figure which shows the preparation procedures of a negative electrode wet granulated body (negative electrode compound material). It is a figure which shows the one aspect | mode of a wet granulation body. It is a figure explaining a roll formation process, and is equivalent to the A section enlarged view of FIG. It is another figure explaining a roll forming process, and is corresponded to the A section enlarged view of FIG. It is a flowchart which shows the flow of the manufacturing method of a positive electrode sheet. It is a subroutine of the flowchart of FIG. It is a figure which shows the preparation procedures of a positive electrode wet granulation body (positive electrode compound material). It is the perspective schematic of the roll film-forming apparatus concerning Example 3,4. It is the side view schematic of the roll film-forming apparatus. It is the perspective schematic of the roll film-forming apparatus concerning Example 5, 6. It is the side view schematic of the roll film-forming apparatus. It is the perspective schematic of the roll film-forming apparatus concerning Example 7, 8. It is the side view schematic of the roll film-forming apparatus. It is a figure explaining the method of calculating | requiring liquid bridge | crosslinking force. It is another figure explaining the method of calculating | requiring liquid bridge | crosslinking force. It is a figure explaining the defect in a roll forming process. It is a figure explaining the film-forming defect (film-forming defect).

Example 1
Hereinafter, a first embodiment of the present invention will be described in detail with reference to the drawings. The present Example 1 applies this invention to manufacture of the negative electrode sheet (electrode sheet) of a lithium ion secondary battery. In the first embodiment, a negative electrode active material (electrode active material), a binder, and a negative electrode material (electrode mixture) for forming the negative electrode mixture layer (electrode mixture layer) of the negative electrode sheet. Use the solvent.

In Example 1, a powdery carbon material (specifically, amorphous coated graphite) is used as the negative electrode active material. Also, water is used as a solvent. Also, CMC (carboxymethyl cellulose) is used as a binder.
As shown in FIG. 3, the negative electrode sheet 19 manufactured in the first embodiment has a negative electrode current collector foil 7 and a negative electrode mixture layer 18 laminated on the surface of the negative electrode current collector foil 7.

  Here, the manufacturing method of the electrode sheet (negative electrode sheet 19) concerning the present Example 1 is demonstrated in detail. FIG. 1 is a schematic perspective view of a roll film-forming apparatus 20 according to a first embodiment. FIG. 2 is a schematic side view of the roll film forming apparatus 20. As shown in FIG. FIG. 4 is a flowchart showing a flow of a method of manufacturing the electrode sheet (negative electrode sheet 19) according to the first embodiment. FIG. 5 is a subroutine of the flowchart of FIG. 4 and is a flowchart showing a flow of a method of manufacturing the negative electrode composite material 6. FIG. 6 is a diagram showing a preparation procedure of the negative electrode wet granulated body 16 (negative electrode mixture 6).

  As shown in FIG. 4, first, in step S1 (electrode mixture production step), granulation is performed while mixing the negative electrode active material 13 (carbon material), the binder 14 (CMC) and the solvent 15 (water). A large number of negative electrode wet granulated bodies 16 are produced, and a negative electrode composite 6 composed of a large number of negative electrode wet granulated bodies 16 is produced. Specifically, as shown in FIG. 5, in step S11 (first mixing step), the negative electrode active material 13 and the binding material 14 are mixed to produce the precursor mixture 6A. In the first embodiment, the negative electrode active material 13 and the binder 14 are charged into a known stirring granulator (not shown) and stirred to mix the negative electrode active material 13 and the binder 14 (see FIG. It disperse | distributes, and is making it the prior mixture 6A (refer FIG. 6).

  Next, the process proceeds to step S12 (second mixing step), and the preceding mixture 6A formed by mixing the negative electrode active material 13 and the binder 14 is mixed with water which is the solvent 15, and the negative electrode wet granulated material is obtained. 16 is produced, and a negative electrode composite 6 composed of a large number of negative electrode wet granules 16 is produced. Specifically, water, which is the solvent 15, is added to the above-described stirring granulator in which the preceding mixture 6A formed by mixing the negative electrode active material 13 and the binding material 14 is contained, and the mixture is stirred. A large number of negative electrode wet granules 16 are obtained. In the mixing of step S12 (second mixing step), all the components constituting the negative electrode wet granulated body 16 are mixed. By performing this all component mixing, the negative electrode composite 6 composed of a large number of negative electrode wet granules 16 is obtained.

  Further, in step S12 (second mixing step) of the first embodiment, the rotational speed of stirring is changed between the first half and the second half of the process. Specifically, the first half is a low speed rotation, and the leading mixture 6A formed by mixing the negative electrode active material 13 and the binder 14 and water as the solvent 15 are stirred (mixed). As a result, it is possible to prepare a wet granulated body by appropriately granulating the negative electrode active material 13 and the binder 14 while absorbing (holding) the solvent 15 (water). However, the wet granulated body obtained by stirring at low speed rotation is too large in particle diameter, and can not be appropriately made into a film in step S2 (roll forming step) described later. For this reason, in the second half of step S12 (second mixing step), stirring is performed at high speed, and the wet granulated body is refined to form a negative electrode wet structure having a particle diameter that can be appropriately film-like in step S2 (roll forming step) The particles 16 are used (see FIG. 6).

  In addition, as shown in FIG. 7, the negative electrode wet granulated body 16 is in a state where water as the solvent 15 is held (absorbed) by the plurality of particles of the negative electrode active material 13 and the binder 14 (not shown). These are substances (particulate bodies) in which they are assembled (bonded). The negative electrode mixture 6 is an assembly of such negative electrode wet granules 16.

  Moreover, in the present Example 1, the compounding ratio of each component mixed in step S11 (1st mixing process) and step S12 (2nd mixing process) is performed as follows. In step S11 (first mixing step), the mixing ratio (blending ratio) of the negative electrode active material 13 to the binder 14 is 99: 1 in weight ratio. In step S12 (second mixing step), the solvent 15 (water) is blended so that the NV (solid content) of the negative electrode wet granulated body 16 is 71% in weight ratio. Specifically, the components other than the solvent 15 (water), that is, the negative electrode active material 13 and the binder 14 are solid components (nonvolatile components), and the total weight of them is the total weight of the negative electrode wet granules 16 The total weight of the negative electrode active material 13, the binder 14 and the solvent 15 is 71 wt%.

  Next, the process proceeds to step S2 (roll forming step), and the negative electrode composite material 6 (negative electrode wet granulated body 16) produced in step S1 (electrode mixture production step) is rotated opposite to the first roll 1. The negative electrode mixture 6 is compressed while passing through the gap with the second roll 2 to form a film, and the negative electrode mixture 6 in the form of a film is attached to the surface 2 b of the second roll 2 (FIG. 1 and FIG. 2). reference). Thereafter, the process proceeds to step S3 (transfer step), and the film-like negative electrode composite material 6 (referred to as a film-like negative electrode composite material 8) attached to the surface 2b of the second roll 2 is formed on the surface of the negative electrode current collector foil 7. Transfer to In the first embodiment, step S2 (roll forming step) and step S3 (transfer step) are continuously performed using the roll film forming apparatus 20 shown in FIGS. 1 and 2.

  The roll film-forming apparatus 20 has three rolls, the 1st roll 1, the 2nd roll 2, and the 3rd roll 3, as shown in FIG.1 and FIG.2. These three rolls 1, 2, 3 are arranged in line in the horizontal direction and provided parallel to each other. Further, the first roll 1 and the second roll 2 face each other at a slight distance. Similarly, the second roll 2 and the third roll 3 also face each other at a slight distance. Further, on the upper side of the facing position of the first roll 1 and the second roll 2, the partition plates 4 and 5 are arranged separately in the width direction of the roll (axial direction, the direction orthogonal to the paper in FIG. 2) ing.

  In addition, as shown by the arrows in FIGS. 1 and 2, the rotation directions of these three rolls 1 to 3 are such that the rotation directions of two adjacent rolls (facing) are opposite to each other, that is, facing each other The two rolls are set to rotate in the forward direction with respect to each other. And in the facing location of the 1st roll 1 and the 2nd roll 2, the surface of these rolls is moved downward by rotation. Moreover, in the facing location of the 2nd roll 2 and the 3rd roll 3, the surface of these rolls is moved upwards by rotation.

  The peripheral speed of the roll (moving speed of the surface of the roll due to rotation) is set to be the slowest in the first roll 1, the fastest in the third roll 3, and the middle in the second roll 2 . Therefore, in step S2 (roll forming step), the peripheral speed of the second roll 2 is made faster than the peripheral speed of the first roll 1.

  In such a roll film-forming apparatus 20, step S1 (electrode mixture preparation process) in the accommodation space between the partition plates 4 and 5 located on the facing location of the first roll 1 and the second roll 2 The negative electrode mixture 6 (negative electrode wet granulated body 16) manufactured in the above is charged. Further, the negative electrode current collector foil 7 is stretched around the third roll 3. The negative electrode current collector foil 7 is a metal foil (copper foil), passes through the facing position of the second roll 2 and the third roll 3 with the rotation of the third roll 3, and from the lower right to the upper right of the third roll 3. It is to be transported to. Moreover, in the facing location of the 2nd roll 2 and the 3rd roll 3, there is a slight gap between the 2nd roll 2 and the negative electrode current collector foil 7 in the state where the negative electrode current collector foil 7 is passed. It is made to be. That is, the gap between the second roll 2 and the third roll 3 (the gap in the state where the negative electrode current collector foil 7 does not exist) is slightly wider than the thickness of the negative electrode current collector foil 7.

  In step S2 (roll forming step), first, the negative electrode mixture 6 is introduced into the accommodation space between the partition plates 4 and 5 of the roll film forming apparatus 20. Then, the charged negative electrode composite material 6 is supplied into the gap between the facing positions of the first roll 1 and the second roll 2, and the gap between both rolls is generated by the rotation of the first roll 1 and the second roll 2. To form a film (see FIGS. 1, 2 and 8). At this time, since the peripheral speed of the second roll 2 is faster than that of the first roll 1, as shown in FIG. 8, the negative electrode wet granulated body 16 contained in the negative electrode mixture 6 has the surface 1 b of the first roll 1. The second roll 2 is stretched more than the surface 2 b of the second roll 2 and has a larger contact area (liquid cross-linked area) on the surface 2 b of the second roll 2 than the surface 1 b of the first roll 1. Adhere to (carried) on the surface 2b of the FIG. 8 is an enlarged view of a portion A of FIG.

The film-like negative electrode composite material 6 (film-like negative electrode composite material 8) attached to the surface 2b of the second roll 2 is transported along with the rotation of the second roll 2 (see FIGS. 1 and 2). Thereafter, the negative electrode current collector foil 7 and the film-like negative electrode composite material 8 meet at a facing position of the second roll 2 and the third roll 3.
Then, in step S3 (transfer step), the film-like negative electrode composite material 8 is transferred from the second roll 2 onto the surface of the negative electrode current collector foil 7 rotating with the third roll 3 having a higher moving speed. (Adhere to). As a result, a current collector foil 9 with a film-like negative electrode mixture is obtained, in which the film-like negative electrode mixture 8 is formed on the negative electrode current collector foil 7.

  By the way, when manufacturing the negative electrode composite 6 which consists of the negative electrode wet granulated body 16 in step S1 (electrode mixture preparation process), it is difficult to disperse | distribute the solvent 15 uniformly over the whole negative electrode composite 6. For this reason, in the negative electrode mixture 6, a large variation may occur in the solid fraction (in other words, the solvent content) of the plurality of negative electrode wet granulated bodies 16 constituting the negative electrode mixture 6. That is, the negative electrode wet granulated body 16 having a high solid fraction (in other words, low solvent content) and the negative electrode wet granulated body 16 having a low solid fraction (in other words, high solvent content) It may be mixed in the negative electrode mixture 6.

  Further, also in each of the negative electrode wet granulated bodies 16 constituting the negative electrode mixture 6, a large variation occurred in the solid fraction (in other words, the solvent content). That is, in one negative electrode wet granulated body 16, a portion having a high solid fraction (in other words, a low solvent content) and a portion having a low solid fraction (in other words, a high solvent content) Could be mixed. For example, in the negative electrode wet granulated body 16B shown in FIG. 7, the portion on the right side in the figure is the first portion 16B1 having a relatively high solid content (in other words, the low solvent content). The second portion 16B2 is relatively low in solid fraction (in other words, high in solvent content), and the solid fraction (solvent content) is between the first portion 16B1 and the second portion 16B2. Are very different.

  Conventionally, when the negative electrode composite material 6 composed of such a negative electrode wet granulated body 16 passes through the gap between the first and second rolls 1 and 2 which are oppositely rotated in step S2 (roll forming step), A part of the negative electrode wet granules 16 in the negative electrode mixture 6 may not adhere to the surface 2 b of the second roll 2 and may adhere to the surface 1 b of the first roll 1. For this reason, the film of the negative electrode mixture 6 attached to the surface 2 b of the second roll 2 may have holes (or the film thickness may be extremely thin in part). As a result, in the step S3 (transfer step), a hole was formed in the film (film-like negative electrode composite 8) of the negative electrode composite 6 transferred onto the surface of the negative electrode current collector foil 7 from the surface 2b of the second roll 2. A film formation failure (film formation defect) may occur that is in the state (or the film thickness becomes extremely thin partially). When this film formation defect (film formation defect) is large, it may not be used appropriately as the negative electrode sheet 19 constituting the battery.

  The reason why such a defect occurs is considered as follows. Specifically, for example, as shown in FIG. 7, the first portion 16B1 having a high solid fraction (in other words, low solvent content) and a low solid fraction (in other words, high solvent content) The negative electrode wet granulated body 16B having the second portion 16B2 is, as shown in FIG. 8, a gap between the first roll 1 and the second roll 2 facing each other in step S2 (roll forming step). When passing through, when the first portion 16B1 contacts the surface 2b of the second roll 2 and the second portion 16B2 contacts the surface 1b of the first roll 1, the negative electrode wet granulated body 16B and the first portion The liquid crosslinking force with the surface 1 b of the roll 1 tends to be larger than the liquid crosslinking force with the negative electrode wet granulated body 16 B and the surface 2 b of the second roll 2.

  For this purpose, as shown in FIG. 21, when the negative electrode wet granulated body 16B passes through the gap between the first roll 1 and the second roll 2 which rotate in the opposite direction in step S2 (roll forming step). In addition, it may adhere to the surface 1 b of the first roll 1 without adhering to the surface 2 b of the second roll 2. For this reason, in the film (film-like negative electrode mixture 8) of the negative electrode mixture 6 attached to the surface 2b of the second roll 2, a hole is opened at the site where the negative electrode wet granulated body 16B has fallen (or At the site, the thickness of the film may be extremely reduced). As a result, also in the film (film-like negative electrode composite material 8) of the negative electrode composite material 6 transferred onto the surface of the negative electrode current collector foil 7 from the surface 2b of the second roll 2 in step S3 (transfer step). As shown in (1), it is considered that the hole H is opened at the site (or the thickness of the film becomes extremely thin at the site) and a deposition failure (deposition defect) occurs.

  On the other hand, in the first embodiment, the roll deposition device 20 is provided with the drying device 60. The drying device 60 includes an air nozzle 61 having an air outlet 61b for blowing the air AR to the outside (see FIGS. 1 and 2). The air nozzle 61 is disposed such that the air outlet 61 b faces the surface 1 b of the first roll 1. In the roll forming step of the first embodiment, the air AR is sprayed from the air nozzle 61 of the drying device 60 to the surface 1 b of the first roll 1 to dry the surface 1 b of the first roll 1. The negative electrode wet granulated body 16) is passed through the gap between the first roll 1 and the second roll 2.

  As described above, by drying the surface 1 b of the first roll 1 by blowing the air AR (atmosphere) onto the surface 1 b of the first roll 1, the moisture content of the surface 1 b of the first roll 1 can be reduced. It can be less than the amount of water on the surface 2b. In other words, the water content of the surface 2 b of the second roll 2 can be made larger than the water content of the surface 1 b of the first roll 1. Thereby, in step S2 (roll forming step), the negative electrode wet granulated body 16 contained in the negative electrode mixture 6 and the negative electrode mixture 6 when the negative electrode mixture 6 passes through the gap between the first roll 1 and the second roll 2 Average value F1 (kPa) of liquid crosslinking power between the surface 1b of the 1 roll 1 and liquid crosslinking power between the negative electrode wet granulated body 16 contained in the negative electrode mixture 6 and the surface 2b of the second roll 2 And the average value F2 (kPa) of the above satisfies the relationship of F1 <F2.

  By doing this, in step S2 (roll forming step), the negative electrode wet granulated body 16 contained in the negative electrode mixture 6 passes through the gap between the first roll 1 and the second roll 2 which rotate oppositely. When doing, it becomes easy to adhere to the surface 2b of the 2nd roll 2 with a large liquid crosslinking force among the 1st roll 1 and the 2nd roll 2. As shown in FIG. Therefore, in the film (film-like negative electrode mixture 8) of the negative electrode mixture formed on the surface 2b of the second roll 2, it becomes difficult for the holes (or the extreme reduction of the film thickness) to occur, and the subsequent step S3 ( In the transfer step, holes (or an extreme decrease in film thickness) are less likely to occur in the film (film-like negative electrode mixture 8) of the negative electrode mixture 6 transferred onto the surface of the negative electrode current collector foil 7. That is, film formation defects (film formation defects) are less likely to occur.

  Specifically, for example, as shown in FIG. 7, the first portion 16B1 having a high solid fraction (in other words, low solvent content) and a low solid fraction (in other words, high solvent content) The negative electrode wet granulated body 16B having the second portion 16B2 is, as shown in FIG. 8, a gap between the first roll 1 and the second roll 2 facing each other in step S2 (roll forming step). Even when the first portion 16B1 comes in contact with the surface 2b of the second roll 2 and the second portion 16B2 comes in contact with the surface 1b of the first roll 1 when passing through, the negative electrode wet granulated body 16B and the second roll The liquid crosslinking force between the second surface 2 b and the second surface 2 b may be larger than the liquid crosslinking force between the negative electrode wet granulated body 16 B and the surface 1 b of the first roll 1. Moreover, since the peripheral speed of the second roll 2 is faster than that of the first roll 1, as shown in FIG. 8, the negative electrode wet granulated body 16 B is more effective than the surface 1 b of the first roll 1. The surface 2b is stretched more largely, and the contact area (liquid cross-linking area) on the surface 2b of the second roll 2 becomes larger than the surface 1b of the first roll 1. Thereby, as shown in FIG. 9, the negative electrode wet granulated body 16 B can be attached to the surface 2 b of the second roll 2.

  Therefore, in the roll forming step (step S2) of the first embodiment, one of the films contained in the negative electrode mixture 6 in the film (film-like negative electrode mixture 8) of the negative electrode mixture 6 attached to the surface 2b of the second roll 2 It becomes difficult to produce the hole (or the extreme reduction of film thickness) resulting from adhesion of the negative electrode wet granulated body 16 of part to the surface 1 b of the first roll 1. As a result, in the subsequent transfer step (step S3), a hole is also formed in the film (film-like negative electrode composite 8) of the negative electrode composite 6 transferred from the surface 2b of the second roll 2 onto the surface of the negative electrode current collector foil 7 (Or, the film thickness is extremely reduced) is less likely to occur, and the film formation failure (film formation defect) is less likely to occur.

  Thereafter, the process proceeds to step S4 (electrode mixture layer forming step) to dry the current collector foil 9 with the film negative electrode mixture in a drying furnace not shown (a film negative electrode transferred onto the surface of the negative electrode current collector foil 7) Dry the mixture 8). As a result, the solvent 15 (water) absorbed (held) in the film-like negative electrode composite 8 (negative electrode wet granulated body 16) is removed (evaporated), and the film-like negative electrode composite 8 becomes the negative electrode composite Layer 18 (electrode mixture layer) is obtained (see FIG. 2). Thereby, the negative electrode sheet 19 (see FIG. 3) having the negative electrode mixture layer 18 on the surface of the negative electrode current collector foil 7 is obtained.

  In the first embodiment, an example is shown in which the film-like negative electrode mixture 8 (negative electrode mixture layer 18) is formed only on one side of the negative electrode current collector foil 7 (that is, a single-sided coated negative electrode sheet is manufactured). However, they may be formed on both sides of the negative electrode current collector foil 7 (that is, to manufacture a double-sided coated negative electrode sheet). When the negative electrode mixture layer 18 is formed on both sides of the negative electrode current collector foil 7, a single-sided coated negative electrode sheet having the negative electrode mixture layer 18 formed on one side of the negative electrode current collector foil 7 is manufactured. The processing of steps S2, S3 and S4 may be performed on the surface of the negative electrode current collector foil 7 of the negative electrode sheet where the negative electrode mixture layer 18 is not formed.

  The produced negative electrode sheet 19 is then combined with a positive electrode sheet 49 described later and a separator to form an electrode body. Subsequently, after attaching a terminal member to this electrode body, an electrode body and electrolyte solution are stored in a battery case. Thereby, a lithium ion secondary battery is completed.

(Example 2)
Next, a second embodiment of the present invention will be described in detail with reference to the drawings. The present Example 2 applies this invention to manufacture of the positive electrode sheet (electrode sheet) of a lithium ion secondary battery. In Example 2, as a material of a positive electrode mixture (electrode mixture) for forming a positive electrode mixture layer (electrode mixture layer) of a positive electrode sheet, a positive electrode active material (electrode active material), a binder and Using a conductive material and a solvent.

In Example 2, nickel cobalt lithium aluminate is used as the positive electrode active material. In addition, acetylene black is used as a conductive material. In addition, polyvinylidene fluoride (hereinafter also referred to as PVdF) is used as a binder. In addition, N-methyl pyrrolidone (hereinafter also referred to as NMP) is used as a solvent.
The positive electrode sheet 49 manufactured in the present Example 2 has the positive electrode current collection foil 37 and the positive electrode composite material layer 48 laminated | stacked on the surface of this positive electrode current collection foil 37, as shown in FIG.

  Here, the manufacturing method of the electrode sheet (positive electrode sheet 49) concerning the present Example 2 is demonstrated in detail. FIG. 10 is a flowchart showing a flow of a method of manufacturing the electrode sheet (positive electrode sheet 49) according to the second embodiment. FIG. 11 is a subroutine of the flowchart of FIG. 10, and is a flowchart showing a flow of a method of manufacturing the positive electrode composite 36. FIG. 12 is a diagram showing a preparation procedure of the positive electrode wet granulated body 56 (positive electrode mixture 36). In the second embodiment, as in the first embodiment, step T2 (roll forming step) and step T3 (transfer step) described later are performed using the roll film forming apparatus 20 shown in FIGS. 1 and 2.

  As shown in FIG. 10, first, in step T1 (electrode mixture producing step), the positive electrode active material 33, the conductive material 44, the binder 34 and the solvent 35 are mixed and granulated to form a large number of positive electrode wet structures While producing the particle | grains 56, the positive electrode compound material 36 which consists of many positive electrode wet granulation bodies 56 is produced. Specifically, as shown in FIG. 11, in step T11 (the first mixing step), the positive electrode active material 33 and the conductive material 44 are mixed using a known stirring granulator (not shown) and preceded mixing Create body 36A. (See Figure 12).

  Subsequently, the process proceeds to step T12 (second mixing step), and the positive electrode wet granulation is performed by mixing the preceding mixture 36A formed by mixing the positive electrode active material 33 and the conductive material 44, the binder 34 and the solvent 35. While producing the body 56, a positive electrode composite 36 composed of a large number of positive electrode wet granules 56 is produced. Specifically, a mixed solution in which the binder 34 and the solvent 35 are mixed is added to the stirring granulator in which the preceding mixture 36A formed by mixing the positive electrode active material 33 and the conductive material 44 is contained, A large number of positive electrode wet granules 56 are formed by stirring. In the mixing of step T12 (second mixing step), all the components constituting the positive electrode wet granulated body 56 are mixed. By performing this all component mixing, a positive electrode composite 36 composed of a large number of positive electrode wet granules 56 is obtained.

  In addition, as shown in FIG. 7, in the positive electrode wet granulated body 56, NMP as the solvent 35 includes particles of a plurality of positive electrode active materials 33, particles of a conductive material 44 (not shown), and a binder 34 (not shown). These are substances (particulate bodies) which are aggregated (bonded) in a state of being retained (absorbed). The positive electrode mixture 36 is an assembly of such positive electrode wet granules 56.

  Moreover, in the present Example 1, the compounding ratio of each component mixed in step T11 (1st mixing process) and step T12 (2nd mixing process) is performed as follows. The mixing ratio (blending ratio) of the positive electrode active material 33 which is solid content, the conductive material 44 and the binder 34 is 94.4: 4.1: 1.5 in weight ratio. Further, in step T12 (second mixing step), the solvent 35 is blended so that the NV (solid content) of the positive electrode wet granulated body 56 is 81% by weight.

  Next, the process proceeds to step T2 (roll forming step), and the positive electrode mixture 36 (positive electrode wet granulated body 56) manufactured in step T1 (electrode mixture producing step) is rotated opposite to the first roll 1. The positive electrode mixture 36 is compressed while passing through the gap with the second roll 2 to form a film, and the positive electrode mixture 36 in a film form is attached to the surface 2 b of the second roll 2 (FIG. 1 and FIG. 2). reference). Thereafter, the process proceeds to step T3 (transfer step), and the film-like positive electrode composite 36 (referred to as a film-like positive electrode composite 38) attached to the surface 2b of the second roll 2 is formed on the surface of the positive electrode current collector foil 37. Transfer to As a result, a current collector foil 39 with a film-like positive electrode mixture is obtained, in which the film-like positive electrode mixture 38 is formed on the positive electrode current collector foil 37.

  By the way, also in the second embodiment, the roll film forming apparatus 20 is provided with the drying device 60 as in the first embodiment. Also in the roll forming process of the second embodiment, the air nozzle 61 of the drying device 60 sprays the air AR onto the surface 1 b of the first roll 1 in the same manner as the roll forming process of the first embodiment. The positive electrode mixture 36 (positive electrode wet granulated body 56) is passed through the gap between the first roll 1 and the second roll 2 while drying 1b (see FIGS. 1 and 2).

  As described above, by drying the surface 1 b of the first roll 1 by blowing the air AR (atmosphere) onto the surface 1 b of the first roll 1, the moisture content of the surface 1 b of the first roll 1 can be reduced. It can be less than the amount of water on the surface 2b. In other words, the water content of the surface 2 b of the second roll 2 can be made larger than the water content of the surface 1 b of the first roll 1. Thereby, in step T2 (roll forming step), when the positive electrode mixture 36 passes through the gap between the first roll 1 and the second roll 2, the positive electrode wet granulated body 56 contained in the positive electrode mixture 36 and the Average value F1 (kPa) of liquid crosslinking power between the surface 1b of 1 roll 1 and liquid crosslinking power between the positive electrode wet granulated body 56 contained in the positive electrode mixture 36 and the surface 2b of the second roll 2 And the average value F2 (kPa) of the above satisfies the relationship of F1 <F2.

  By doing this, in step T2 (roll forming step), the positive electrode wet granulated body 56 contained in the positive electrode mixture 36 passes through the gap between the first roll 1 and the second roll 2 which rotate oppositely. When doing, it becomes easy to adhere to the surface 2b of the 2nd roll 2 with a large liquid crosslinking force among the 1st roll 1 and the 2nd roll 2. As shown in FIG. Therefore, in the film (film-like positive electrode mixture 38) of the positive electrode mixture 36 formed on the surface 2b of the second roll 2, it becomes difficult to cause holes (or an extreme reduction in film thickness), and step T3 described later In the (transfer step), a hole (or an extreme decrease in film thickness) hardly occurs in the film (film-like positive electrode mixture 38) of the positive electrode mixture 36 transferred onto the surface of the positive electrode current collector foil 37. That is, film formation defects (film formation defects) are less likely to occur.

  Specifically, for example, as shown in FIG. 7, the first portion 56B1 having a high solid content (in other words, low solvent content) and a low solid content (in other words, high solvent content) The positive electrode wet granulated body 56B having the second portion 56B2 is, as shown in FIG. 8, a gap between the first roll 1 and the second roll 2 which are oppositely rotated in step T2 (roll forming step). Even when the first portion 56B1 contacts the surface 2b of the second roll 2 and the second portion 56B2 contacts the surface 1b of the first roll 1 when passing through, the positive electrode wet granulated body 56B and the second roll The liquid crosslinking force between the second surface 2 b and the second surface 2 b may be larger than the liquid crosslinking force between the positive electrode wet granulated body 56 B and the surface 1 b of the first roll 1. Moreover, since the second roll 2 has a higher peripheral speed than the first roll 1, as shown in FIG. 8, the positive electrode wet granulated body 56 </ b> B is made of the second roll 2 rather than the surface 1 b of the first roll 1. The surface 2b is stretched more largely, and the contact area (liquid cross-linking area) on the surface 2b of the second roll 2 becomes larger than the surface 1b of the first roll 1. Thereby, as shown in FIG. 9, the positive electrode wet granulated body 56 </ b> B can be attached to the surface 2 b of the second roll 2.

  Thereafter, the process proceeds to step T4 (electrode mixture layer forming step) to dry the current collector foil 39 with the film positive electrode mixture in a drying furnace not shown (a film positive electrode transferred onto the surface of the positive electrode current collector foil 37). Dry the mixture 38). As a result, the solvent 35 absorbed (held) in the film-like positive electrode mixture 38 (the positive electrode wet granulated body 56) is removed (evaporated), and the film-like positive electrode mixture 38 becomes the positive electrode mixture layer 48 (the material). The electrode mixture layer (see FIG. 2). Thereby, the positive electrode sheet 49 (see FIG. 3) having the positive electrode mixture layer 48 on the surface of the positive electrode current collector foil 37 is obtained.

  In the second embodiment, an example is shown in which the film-like positive electrode mixture 38 (positive electrode mixture layer 48) is formed only on one side of the positive electrode current collector foil 37 (that is, a single-sided coated positive electrode sheet is manufactured). However, they may be formed on both sides of the positive electrode current collector foil 37 (that is, a double-sided coated positive electrode sheet is manufactured). When the positive electrode mixture layer 48 is formed on both sides of the positive electrode current collector foil 37, a single-sided coated positive electrode sheet having the positive electrode mixture layer 48 formed on one side of the positive electrode current collector foil 37 is manufactured. The process of steps T2, T3 and T4 may be performed on the surface of the positive electrode current collector foil 37 of the positive electrode sheet where the positive electrode mixture layer 48 is not formed.

(Example 3)
Next, a third embodiment of the present invention will be described in detail with reference to the drawings. The third embodiment differs from the first embodiment only in the roll film forming apparatus used to perform step S2 (roll forming step) and step S3 (transfer step), and the other is the same. . Therefore, here, differences from the first embodiment will be mainly described, and description of the same points will be omitted or simplified.

  This Example 3 applies this invention to manufacture of the negative electrode sheet 19 (electrode sheet) of a lithium ion secondary battery like Example 1. FIG. In the third embodiment, as in the first embodiment, the negative electrode active material 13 is used as a material of the negative electrode mixture 6 (electrode mixture) for forming the negative electrode mixture layer 18 (electrode mixture layer) of the negative electrode sheet 19. (Electrode active material), binder 14 and solvent 15 are used. Hereinafter, the manufacturing method of the electrode sheet (negative electrode sheet 19) concerning the present Example 3 is demonstrated in detail.

  As shown in FIG. 4, first, in step S1 (electrode mixture production step), granulation is performed while mixing the negative electrode active material 13 (carbon material), the binder 14 (CMC) and the solvent 15 (water). A large number of negative electrode wet granulated bodies 16 are produced, and a negative electrode composite 6 composed of a large number of negative electrode wet granulated bodies 16 is produced. That is, a negative electrode mixture 6 equivalent to that of Example 1 is manufactured.

  Next, the process proceeds to step S2 (roll forming step), and the negative electrode composite material 6 (negative electrode wet granulated body 16) manufactured in step S1 (electrode mixture material manufacturing step) is rotated opposite to the first roll 1 and The negative electrode mixture 6 is compressed while passing through a gap between the two rolls 2 to form a film, and the negative electrode mixture 6 in the form of a film is attached to the surface 2 b of the second roll 2 (see FIGS. 13 and 14). ). Thereafter, the process proceeds to step S3 (transfer step), and the film-like negative electrode composite material 6 (referred to as a film-like negative electrode composite material 8) attached to the surface 2b of the second roll 2 is formed on the surface of the negative electrode current collector foil 7. Transfer to

In the third embodiment, unlike the first embodiment, step S2 (roll forming step) and step S3 (transfer step) are performed using the roll film forming apparatus 120 shown in FIGS. 13 and 14.
As shown in FIGS. 13 and 14, the roll film forming apparatus 120 of the third embodiment is different from the roll film forming apparatus 20 of the first embodiment only in that the drying device 60 is changed to the drying device 160. , Others are similar.

  The drying device 160 provided in the roll film forming apparatus 120 of the third embodiment includes an air nozzle 161 having an air outlet 161 b for blowing the dry air DAR to the outside (see FIGS. 13 and 14). The air nozzle 161 is disposed such that the air outlet 161 b faces the surface 1 b of the first roll 1. In the roll forming step of the third embodiment, the dry air DAR is sprayed from the air nozzle 161 of the drying device 160 to the surface 1 b of the first roll 1 to dry the surface 1 b of the first roll 1. The negative electrode wet granulated body 16) is passed through the gap between the first roll 1 and the second roll 2. In the third embodiment, the dry air DAR having a dew point of −30 ° C. or less is sprayed on the surface 1 b of the first roll 1.

  In the third embodiment, the surface 1 b of the first roll 1 is dried by spraying the dry air DAR on the surface 1 b of the first roll 1 as described above, compared with the first embodiment. The water content of the surface 1 b can be made even smaller than the water content of the surface 2 b of the second roll 2. In other words, the amount of water on the surface 2 b of the second roll 2 can be made much larger than the amount of water on the surface 1 b of the first roll 1 as compared with the first embodiment.

  Thereby, in Example 3, the negative electrode wet included in the negative electrode mixture 6 when the negative electrode mixture 6 passes through the gap between the first roll 1 and the second roll 2 in step S2 (roll forming step). Average value F1 (kPa) of liquid crosslinking force between the granules 16 and the surface 1b of the first roll 1 and the surface 2b of the negative electrode wet granules 16 contained in the negative electrode mixture 6 and the second roll 2 And the average value F2 (kPa) of the liquid crosslinking force satisfy the relationship of F1 <F2. Specifically, in the third embodiment, the difference between F1 and F2 can be increased as compared with the first embodiment. That is, F2 can be made larger than F1.

  By doing this, in step S2 (roll forming step), the negative electrode wet granulated body 16 contained in the negative electrode mixture 6 passes through the gap between the first roll 1 and the second roll 2 which rotate oppositely. At this time, it becomes easier to adhere to the surface 2 b of the second roll 2 having a relatively large liquid crosslinking ability among the first roll 1 and the second roll 2. Therefore, in the film (film-like negative electrode mixture 8) of the negative electrode mixture formed on the surface 2b of the second roll 2, the holes (or the extreme reduction of the film thickness) become even more difficult to occur, and the later steps In the film (film-like negative electrode mixture 8) of the negative electrode mixture 6 transferred onto the surface of the negative electrode current collector foil 7 in S3 (transfer step), holes (or an extreme decrease in film thickness) are more unlikely to occur Become. That is, film formation defects (film formation defects) are further less likely to occur.

  Thereafter, the process proceeds to step S4 (electrode mixture layer forming step) to dry the current collector foil 9 with the film negative electrode mixture in a drying furnace not shown (a film negative electrode transferred onto the surface of the negative electrode current collector foil 7) Dry the mixture 8). As a result, the solvent 15 (water) absorbed (held) in the film-like negative electrode composite 8 (negative electrode wet granulated body 16) is removed (evaporated), and the film-like negative electrode composite 8 becomes the negative electrode composite Layer 18 (electrode mixture layer) is obtained (see FIG. 2). Thereby, the negative electrode sheet 19 (see FIG. 3) having the negative electrode mixture layer 18 on the surface of the negative electrode current collector foil 7 is obtained.

(Example 4)
Next, a fourth embodiment of the present invention will be described in detail with reference to the drawings. The fourth embodiment is different from the second embodiment only in the roll film forming apparatus used to perform step T2 (roll forming step) and step T3 (transfer step), and the other is the same. . Therefore, here, differences from the second embodiment will be mainly described, and the description of the same points will be omitted or simplified.

  This Example 4 applies this invention to manufacture of the positive electrode sheet 49 (electrode sheet) of a lithium ion secondary battery like Example 2. FIG. In the fourth embodiment, the positive electrode active material 33 is used as a material of the positive electrode mixture 36 (electrode mixture) for forming the positive electrode mixture layer 48 (electrode mixture layer) of the positive electrode sheet 49 as in the second embodiment. (Electrode active material), a binder 34, a conductive material 44, and a solvent 35 are used. Hereinafter, the manufacturing method of the electrode sheet (positive electrode sheet 49) concerning the present Example 4 is demonstrated in detail.

  As shown in FIG. 10, first, in step T1 (electrode mixture producing step), the positive electrode active material 33, the conductive material 44, the binder 34 and the solvent 35 are mixed and granulated to form a large number of positive electrode wet structures While producing the particle | grains 56, the positive electrode compound material 36 which consists of many positive electrode wet granulation bodies 56 is produced. That is, a positive electrode mixture 36 equivalent to that of the second embodiment is manufactured.

  Next, the process proceeds to step T2 (roll forming step), and the positive electrode mixture 36 (positive electrode wet granulated body 56) manufactured in step T1 (electrode mixture producing step) is rotated opposite to the first roll 1. The positive electrode mixture 36 is compressed while passing through the gap with the second roll 2 to form a film, and the positive electrode mixture 36 in the form of a film is attached to the surface 2 b of the second roll 2 (FIG. 13 and FIG. 14). reference). Thereafter, the process proceeds to step T3 (transfer step), and the film-like positive electrode composite 36 (referred to as a film-like positive electrode composite 38) attached to the surface 2b of the second roll 2 is formed on the surface of the positive electrode current collector foil 37. Transfer to

  In the fourth embodiment, unlike the second embodiment, step T2 (roll forming step) and step S3 (transfer step) are performed using the roll film forming apparatus 120 shown in FIGS. 13 and 14. That is, as in the third embodiment, the roll film forming apparatus 120 including the drying device 160 is used as the roll film forming apparatus. Therefore, in the roll forming step of the fourth embodiment, the surface 1 b of the first roll 1 is sprayed by blowing dry air DAR having a dew point of −30 ° C. or less onto the surface 1 b of the first roll 1 from the air nozzle 161 of the drying device 160. The positive electrode mixture 36 (the positive electrode wet granulated body 56) is passed through the gap between the first roll 1 and the second roll 2 while drying.

  Thereby, in Example 4, the positive electrode wet included in the positive electrode mixture 36 when the positive electrode mixture 36 passes through the gap between the first roll 1 and the second roll 2 in step T2 (roll forming step). An average value F1 (kPa) of liquid crosslinking force between the granules 56 and the surface 1b of the first roll 1 and a surface 2b of the positive electrode wet granules 56 contained in the positive electrode mixture 36 and the second roll 2 And the average value F2 (kPa) of the liquid crosslinking force satisfy the relationship of F1 <F2. Specifically, in the fourth embodiment, the difference between F1 and F2 can be increased as compared with the third embodiment. That is, F2 can be made larger than F1.

  By doing this, in step T2 (roll forming step), the positive electrode wet granulated body 56 contained in the positive electrode mixture 36 passes through the gap between the first roll 1 and the second roll 2 which rotate oppositely. At this time, it becomes easier to adhere to the surface 2 b of the second roll 2 having a relatively large liquid crosslinking ability among the first roll 1 and the second roll 2. Therefore, in the film (film-like positive electrode mixture 38) of the positive electrode mixture formed on the surface 2 b of the second roll 2, the holes (or the extreme reduction of the film thickness) become even more difficult to occur, and the later steps In the film (film-like positive electrode mixture 38) of the positive electrode mixture 36 transferred onto the surface of the positive electrode current collector foil 37 in T3 (transfer step), holes (or an extreme decrease in film thickness) are more difficult to occur. Become. That is, film formation defects (film formation defects) are further less likely to occur.

  Thereafter, the process proceeds to step T4 (electrode mixture layer forming step) to dry the current collector foil 39 with the film positive electrode mixture in a drying furnace not shown (a film positive electrode transferred onto the surface of the positive electrode current collector foil 37). Dry the mixture 38). As a result, the solvent 35 absorbed (held) in the film-like positive electrode mixture 38 (the positive electrode wet granulated body 56) is removed (evaporated), and the film-like positive electrode mixture 38 becomes the positive electrode mixture layer 48 (the material). The electrode mixture layer (see FIG. 2). Thereby, the positive electrode sheet 49 (see FIG. 3) having the positive electrode mixture layer 48 on the surface of the positive electrode current collector foil 37 is obtained.

(Example 5)
Next, a fifth embodiment of the present invention will be described in detail with reference to the drawings. The fifth embodiment differs from the first embodiment only in the roll film forming apparatus used to perform step S2 (roll forming step) and step S3 (transfer step), and the other is the same. . Therefore, here, differences from the first embodiment will be mainly described, and description of the same points will be omitted or simplified.

  As shown in FIG. 4, first, in step S1 (electrode mixture production step), granulation is performed while mixing the negative electrode active material 13 (carbon material), the binder 14 (CMC) and the solvent 15 (water). A large number of negative electrode wet granulated bodies 16 are produced, and a negative electrode composite 6 composed of a large number of negative electrode wet granulated bodies 16 is produced. That is, a negative electrode mixture 6 equivalent to that of Example 1 is manufactured.

  Next, the process proceeds to step S2 (roll forming step), and the negative electrode composite material 6 (negative electrode wet granulated body 16) manufactured in step S1 (electrode mixture material manufacturing step) is rotated opposite to the first roll 1 and The negative electrode mixture 6 is compressed while passing through a gap between the two rolls 2 to form a film, and the negative electrode mixture 6 in the form of a film is attached to the surface 2 b of the second roll 2 (see FIGS. 15 and 16). ). Thereafter, the process proceeds to step S3 (transfer step), and the film-like negative electrode composite material 6 (referred to as a film-like negative electrode composite material 8) attached to the surface 2b of the second roll 2 is formed on the surface of the negative electrode current collector foil 7. Transfer to

In the fifth embodiment, unlike the first embodiment, step S2 (roll forming step) and step S3 (transfer step) are performed using the roll film forming apparatus 220 shown in FIGS.
As shown in FIGS. 15 and 16, the roll film-forming apparatus 220 according to the fifth embodiment is provided with the wetting apparatus 260 without providing the drying apparatus 60 as compared with the roll film-forming apparatus 20 according to the first embodiment. The only difference is the point, the others are similar.

  The wetting device 260 provided in the roll film forming apparatus 220 of the fifth embodiment includes the non-woven fabric 261 disposed on the surface 2 b of the second roll 2 and the non-woven fabric 261 against the surface 2 b of the second roll 2. And pressing means (not shown) for pressing (see FIGS. 15 and 16). Among them, the non-woven fabric 261 is impregnated with the liquid L1 (that is, water) equivalent to the solvent 15 contained in the negative electrode mixture 6. Therefore, in the roll forming step of the fifth embodiment, the liquid L 1 contained in the non-woven fabric 261 is obtained by pressing the non-woven fabric 261 against the surface 2 b of the rotating second roll 2 by pressing means (not shown) of the wetting device 260. Is adhered to the surface 2 b of the second roll 2. Thereby, the negative electrode composite material 6 (negative electrode wet granulated body 16) is passed through the gap between the first roll 1 and the second roll 2 while wetting the surface 2 b of the second roll 2.

  In the fifth embodiment, the amount of water on the surface 2 b of the second roll 2 is thus obtained by depositing the liquid L 1 on the surface 2 b of the second roll 2 to wet the surface 2 b of the second roll 2 The amount of water can be greater than the amount of water on the surface 1 b of the first roll 1. Thus, in Example 5, the negative electrode wet included in negative electrode mixture 6 when negative electrode mixture 6 passes through the gap between first roll 1 and second roll 2 in step S2 (roll forming step). Average value F1 (kPa) of liquid crosslinking force between the granules 16 and the surface 1b of the first roll 1 and the surface 2b of the negative electrode wet granules 16 contained in the negative electrode mixture 6 and the second roll 2 And the average value F2 (kPa) of the liquid crosslinking force satisfy the relationship of F1 <F2.

  By doing this, in step S2 (roll forming step), the negative electrode wet granulated body 16 contained in the negative electrode mixture 6 passes through the gap between the first roll 1 and the second roll 2 which rotate oppositely. When doing, it becomes easy to adhere to the surface 2b of the 2nd roll 2 with a large liquid crosslinking force among the 1st roll 1 and the 2nd roll 2. As shown in FIG. Therefore, in the film (film-like negative electrode mixture 8) of the negative electrode mixture formed on the surface 2b of the second roll 2, it becomes difficult for the holes (or the extreme reduction of the film thickness) to occur, and the subsequent step S3 ( In the transfer step), a hole (or an extreme decrease in film thickness) hardly occurs in the film (film-like negative electrode mixture 8) of the negative electrode mixture 6 transferred onto the surface of the negative electrode current collector foil 7. That is, film formation defects (film formation defects) are less likely to occur.

  Thereafter, the process proceeds to step S4 (electrode mixture layer forming step) to dry the current collector foil 9 with the film negative electrode mixture in a drying furnace not shown (a film negative electrode transferred onto the surface of the negative electrode current collector foil 7) Dry the mixture 8). As a result, the solvent 15 (water) absorbed (held) in the film-like negative electrode composite 8 (negative electrode wet granulated body 16) is removed (evaporated), and the film-like negative electrode composite 8 becomes the negative electrode composite Layer 18 (electrode mixture layer) is obtained (see FIG. 2). Thereby, the negative electrode sheet 19 (see FIG. 3) having the negative electrode mixture layer 18 on the surface of the negative electrode current collector foil 7 is obtained.

(Example 6)
Next, a sixth embodiment of the present invention will be described in detail with reference to the drawings. The sixth embodiment is different from the second embodiment only in the roll film forming apparatus used to perform step T2 (roll forming step) and step T3 (transfer step), and the other is the same. . Therefore, here, differences from the second embodiment will be mainly described, and the description of the same points will be omitted or simplified.

  As shown in FIG. 10, first, in step T1 (electrode mixture producing step), the positive electrode active material 33, the conductive material 44, the binder 34 and the solvent 35 are mixed and granulated to form a large number of positive electrode wet structures While producing the particle | grains 56, the positive electrode compound material 36 which consists of many positive electrode wet granulation bodies 56 is produced. That is, a positive electrode mixture 36 equivalent to that of the second embodiment is manufactured.

  Next, the process proceeds to step T2 (roll forming step), and the positive electrode mixture 36 (positive electrode wet granulated body 56) manufactured in step T1 (electrode mixture producing step) is rotated opposite to the first roll 1. The positive electrode mixture 36 is compressed while passing through the gap with the second roll 2 to form a film, and the positive electrode mixture 36 in a film shape is attached to the surface 2 b of the second roll 2 (FIG. 15 and FIG. 16). reference). Thereafter, the process proceeds to step T3 (transfer step), and the film-like positive electrode composite 36 (referred to as a film-like positive electrode composite 38) attached to the surface 2b of the second roll 2 is formed on the surface of the positive electrode current collector foil 37. Transfer to

  In the sixth embodiment, unlike the second embodiment, step S2 (roll forming step) and step S3 (transfer step) are performed using the roll film forming apparatus 220 shown in FIG. 15 and FIG. That is, as in the fifth embodiment, the roll film forming apparatus 220 including the wetting device 260 is used as the roll film forming apparatus. However, in the sixth embodiment, unlike the fifth embodiment, the non-woven fabric 261 of the wetting device 260 is impregnated with the liquid L2 (that is, NMP) equivalent to the solvent 35 contained in the positive electrode mixture 36.

  In the roll forming step of the sixth embodiment, as in the fifth embodiment, the non-woven fabric 261 of the wetting device 260 is pressed against the surface 2 b of the rotating second roll 2 to form the liquid L2 contained in the non-woven fabric 261. By adhering the surface 2 b of the second roll 2 to the surface 2 b of the second roll 2 while wetting the surface 2 b of the second roll 2, a gap between the first roll 1 and the second roll 2 It passes through.

  Thereby, in Example 6, the positive electrode wet included in the positive electrode mixture 36 when the positive electrode mixture 36 passes the gap between the first roll 1 and the second roll 2 in step T2 (roll forming step). An average value F1 (kPa) of liquid crosslinking force between the granules 56 and the surface 1b of the first roll 1 and a surface 2b of the positive electrode wet granules 56 contained in the positive electrode mixture 36 and the second roll 2 And the average value F2 (kPa) of the liquid crosslinking force satisfy the relationship of F1 <F2.

  By doing this, in step T2 (roll forming step), the positive electrode wet granulated body 56 contained in the positive electrode mixture 36 passes through the gap between the first roll 1 and the second roll 2 which rotate oppositely. When doing, it becomes easy to adhere to the surface 2b of the 2nd roll 2 with a large liquid crosslinking force among the 1st roll 1 and the 2nd roll 2. As shown in FIG. Therefore, in the film (film-like positive electrode mixture 38) of the positive electrode mixture formed on the surface 2b of the second roll 2, it becomes difficult for the holes (or the extreme reduction of the film thickness) to occur, and the subsequent step T3 ( Also in the transfer step, holes (or an extreme decrease in film thickness) hardly occur in the film (film-like positive electrode mixture 38) of the positive electrode mixture 36 transferred onto the surface of the positive electrode current collector foil 37. That is, film formation defects (film formation defects) are less likely to occur.

  Thereafter, the process proceeds to step T4 (electrode mixture layer forming step) to dry the current collector foil 39 with the film positive electrode mixture in a drying furnace not shown (a film positive electrode transferred onto the surface of the positive electrode current collector foil 37). Dry the mixture 38). As a result, the solvent 35 absorbed (held) in the film-like positive electrode mixture 38 (the positive electrode wet granulated body 56) is removed (evaporated), and the film-like positive electrode mixture 38 becomes the positive electrode mixture layer 48 (the material). The electrode mixture layer (see FIG. 2). Thereby, the positive electrode sheet 49 (see FIG. 3) having the positive electrode mixture layer 48 on the surface of the positive electrode current collector foil 37 is obtained.

(Example 7)
A seventh embodiment of the present invention will now be described in detail with reference to the drawings. The seventh embodiment differs from the fifth embodiment only in the roll film-forming apparatus used to perform step S2 (roll forming step) and step S3 (transfer step), and the other is the same. . Therefore, here, differences from the first embodiment will be mainly described, and description of the same points will be omitted or simplified.

  As shown in FIG. 4, first, in step S1 (electrode mixture production step), granulation is performed while mixing the negative electrode active material 13 (carbon material), the binder 14 (CMC) and the solvent 15 (water). A large number of negative electrode wet granulated bodies 16 are produced, and a negative electrode composite 6 composed of a large number of negative electrode wet granulated bodies 16 is produced. That is, a negative electrode mixture 6 equivalent to that of Example 1 is manufactured.

  Next, the process proceeds to step S2 (roll forming step), and the negative electrode composite material 6 (negative electrode wet granulated body 16) manufactured in step S1 (electrode mixture material manufacturing step) is rotated opposite to the first roll 1 and The negative electrode mixture 6 is compressed while passing through a gap between the two rolls 2 to form a film, and the negative electrode mixture 6 in the form of a film is attached to the surface 2 b of the second roll 2 (see FIGS. 17 and 18). ). Thereafter, the process proceeds to step S3 (transfer step), and the film-like negative electrode composite material 6 (referred to as a film-like negative electrode composite material 8) attached to the surface 2b of the second roll 2 is formed on the surface of the negative electrode current collector foil 7. Transfer to

In the seventh embodiment, unlike the fifth embodiment, step S2 (roll forming step) and step S3 (transfer step) are performed using a roll film forming apparatus 320 shown in FIGS. 17 and 18.
As compared with the roll film forming apparatus 220 of the fifth embodiment, the roll film forming apparatus 320 of the seventh embodiment is different from the roll film forming apparatus 220 of the fifth embodiment only in that a wetting apparatus 360 is provided in place of the wet apparatus 260. The other is the same.

  The wetting device 360 provided in the roll film-forming apparatus 320 of the seventh embodiment includes a plurality of spray nozzles 361 disposed above the second roll 2 and a liquid supply unit (not shown) for supplying liquid to the spray nozzles 361. And (see FIGS. 17 and 18). In the seventh embodiment, as the liquid supplied to the spray nozzle 361, the liquid L1 (that is, water) equivalent to the solvent 15 contained in the negative electrode mixture 6 is used. Therefore, in the roll forming step of the seventh embodiment, the liquid L1 sprayed downward from the spray nozzle 361 is attached to the surface 2 b of the second roll 2 while wetting the surface 2 b of the second roll 2. The negative electrode mixture 6 (negative electrode wet granulated body 16) is passed through the gap between the first roll 1 and the second roll 2.

  In the seventh embodiment, the moisture content of the surface 2 b of the second roll 2 can be obtained by thus wetting the surface 2 b of the second roll 2 by adhering the liquid L 1 to the surface 2 b of the second roll 2. The amount of water can be greater than the amount of water on the surface 1 b of the first roll 1. Thus, in Example 7, the negative electrode wetting included in negative electrode mixture 6 when negative electrode mixture 6 passes through the gap between first roll 1 and second roll 2 in step S2 (roll forming step). Average value F1 (kPa) of liquid crosslinking force between the granules 16 and the surface 1b of the first roll 1 and the surface 2b of the negative electrode wet granules 16 contained in the negative electrode mixture 6 and the second roll 2 And the average value F2 (kPa) of the liquid crosslinking force satisfy the relationship of F1 <F2.

  By doing this, in step S2 (roll forming step), the negative electrode wet granulated body 16 contained in the negative electrode mixture 6 passes through the gap between the first roll 1 and the second roll 2 which rotate oppositely. When doing, it becomes easy to adhere to the surface 2b of the 2nd roll 2 with a large liquid crosslinking force among the 1st roll 1 and the 2nd roll 2. As shown in FIG. Therefore, in the film (film-like negative electrode mixture 8) of the negative electrode mixture formed on the surface 2b of the second roll 2, it becomes difficult for the holes (or the extreme reduction of the film thickness) to occur, and the subsequent step S3 ( In the transfer step), a hole (or an extreme decrease in film thickness) hardly occurs in the film (film-like negative electrode mixture 8) of the negative electrode mixture 6 transferred onto the surface of the negative electrode current collector foil 7. That is, film formation defects (film formation defects) are less likely to occur.

  Thereafter, the process proceeds to step S4 (electrode mixture layer forming step) to dry the current collector foil 9 with the film negative electrode mixture in a drying furnace not shown (a film negative electrode transferred onto the surface of the negative electrode current collector foil 7) Dry the mixture 8). As a result, the solvent 15 (water) absorbed (held) in the film-like negative electrode composite 8 (negative electrode wet granulated body 16) is removed (evaporated), and the film-like negative electrode composite 8 becomes the negative electrode composite Layer 18 (electrode mixture layer) is obtained (see FIG. 2). Thereby, the negative electrode sheet 19 (see FIG. 3) having the negative electrode mixture layer 18 on the surface of the negative electrode current collector foil 7 is obtained.

(Example 8)
Next, an eighth embodiment of the present invention will be described in detail with reference to the drawings. The eighth embodiment is different from the sixth embodiment only in the roll film forming apparatus used to perform step T2 (roll forming step) and step T3 (transfer step), and the other is the same. . Therefore, here, differences from the sixth embodiment will be mainly described, and the description of the same points will be omitted or simplified.

  As shown in FIG. 10, first, in step T1 (electrode mixture producing step), the positive electrode active material 33, the conductive material 44, the binder 34 and the solvent 35 are mixed and granulated to form a large number of positive electrode wet structures While producing the particle | grains 56, the positive electrode compound material 36 which consists of many positive electrode wet granulation bodies 56 is produced. That is, a positive electrode mixture 36 equivalent to that of the second embodiment is manufactured.

  Next, the process proceeds to step T2 (roll forming step), and the positive electrode mixture 36 (positive electrode wet granulated body 56) manufactured in step T1 (electrode mixture producing step) is rotated opposite to the first roll 1. By passing through the gap with the second roll 2, the positive electrode mixture 36 is compressed and made into a film, and the positive electrode mixture 36 in a film shape is attached to the surface 2b of the second roll 2 (FIG. 17 and FIG. 18). reference). Thereafter, the process proceeds to step T3 (transfer step), and the film-like positive electrode composite 36 (referred to as a film-like positive electrode composite 38) attached to the surface 2b of the second roll 2 is formed on the surface of the positive electrode current collector foil 37. Transfer to

  In the eighth embodiment, unlike the sixth embodiment, step S2 (roll forming step) and step S3 (transfer step) are performed using the roll film forming apparatus 320 shown in FIGS. 17 and 18. That is, as in the seventh embodiment, the roll film forming apparatus 320 including the wetting device 360 is used as the roll film forming apparatus. However, in the eighth embodiment, unlike the seventh embodiment, the liquid L2 (that is, NMP) equivalent to the solvent 35 contained in the positive electrode mixture 36 is used as the liquid supplied to the spray nozzle 361.

  In the roll forming step of the eighth embodiment, as in the seventh embodiment, the liquid L2 sprayed downward from the spray nozzle 361 is attached to the surface 2 b of the second roll 2 to form the surface 2 b of the second roll 2. , And the positive electrode mixture 36 (positive electrode wet granulated body 56) is passed through the gap between the first roll 1 and the second roll 2.

  Thereby, in Example 8, the positive electrode wet included in the positive electrode mixture 36 when the positive electrode mixture 36 passes through the gap between the first roll 1 and the second roll 2 in step T2 (roll forming step). An average value F1 (kPa) of liquid crosslinking force between the granules 56 and the surface 1b of the first roll 1 and a surface 2b of the positive electrode wet granules 56 contained in the positive electrode mixture 36 and the second roll 2 And the average value F2 (kPa) of the liquid crosslinking force satisfy the relationship of F1 <F2.

  By doing this, in step T2 (roll forming step), the positive electrode wet granulated body 56 contained in the positive electrode mixture 36 passes through the gap between the first roll 1 and the second roll 2 which rotate oppositely. When doing, it becomes easy to adhere to the surface 2b of the 2nd roll 2 with a large liquid crosslinking force among the 1st roll 1 and the 2nd roll 2. As shown in FIG. Therefore, in the film (film-like positive electrode mixture 38) of the positive electrode mixture formed on the surface 2b of the second roll 2, it becomes difficult for the holes (or the extreme reduction of the film thickness) to occur, and the subsequent step T3 ( Also in the transfer step, holes (or an extreme decrease in film thickness) hardly occur in the film (film-like positive electrode mixture 38) of the positive electrode mixture 36 transferred onto the surface of the positive electrode current collector foil 37. That is, film formation defects (film formation defects) are less likely to occur.

  Thereafter, the process proceeds to step T4 (electrode mixture layer forming step) to dry the current collector foil 39 with the film positive electrode mixture in a drying furnace not shown (a film positive electrode transferred onto the surface of the positive electrode current collector foil 37). Dry the mixture 38). As a result, the solvent 35 absorbed (held) in the film-like positive electrode mixture 38 (the positive electrode wet granulated body 56) is removed (evaporated), and the film-like positive electrode mixture 38 becomes the positive electrode mixture layer 48 (the material). The electrode mixture layer (see FIG. 2). Thereby, the positive electrode sheet 49 (see FIG. 3) having the positive electrode mixture layer 48 on the surface of the positive electrode current collector foil 37 is obtained.

(Evaluation test of manufacturing method)
Next, a test was conducted to evaluate the manufacturing method of Examples 1 to 4. Specifically, using the roll film forming apparatus 20, 120 of each example, a current collector foil 9 with a film-like negative electrode mixture having a length of 100 m or a current collector foil 39 with a film-like positive electrode mixture was produced. And, regarding the current collector foil 9 with a film-like negative electrode composite material or the current collector foil 39 with a film-like positive electrode composite material of each example, how many film formation defects (film formation defects) occur in 100 m in length investigated. The results are shown in Table 1.

  Moreover, as a comparative example 1, compared with the roll film-forming apparatus 20 of Example 1, the film-form negative mix material of 100 m length using the roll film-forming apparatus which differs only in the point which has not provided the drying apparatus 60. A current collector foil 9 was produced. Furthermore, as Comparative Example 2, a film-like positive electrode composite material of 100 m in length is obtained using a roll film forming apparatus which differs from the roll film forming apparatus 20 of Example 1 only in that the drying apparatus 60 is not provided. A current collector foil 39 was produced. Also about these, it was investigated how many film-forming defects (film-forming defect) have generate | occur | produced in 100 m in length. The results are shown in Table 1.

  Further, in the roll forming process of Examples 1 to 4 and Comparative Examples 1 and 2, “The negative electrode mixture 6 is included in the negative electrode mixture 6 when passing through the gap between the first roll 1 and the second roll 2. Average value F1 (kPa) of liquid crosslinking force between the negative electrode wet granulated body 16 and the surface 1b of the first roll 1 or “a gap between the first roll 1 and the second roll 2 of the positive electrode mixture 36 The average value F1 (kPa) of the liquid crosslinking power between the positive electrode wet granulated body 56 contained in the positive electrode mixture 36 and the surface 1b of the first roll 1 when passing through. In the present test, the average value F1 (kPa) of the liquid crosslinking power is determined as follows.

  Specifically, the average value F1 (kPa) of the liquid crosslinking force was determined using a known powder layer shear force measuring apparatus 90 (see FIG. 19). The powder layer shear force measuring device 90 includes a flat plate 91 having a surface 91 b (the same surface roughness, etc.) equivalent to the surface 1 b of the first roll 1, and a cylinder mounted on the surface 91 b of the flat plate 91. 93 and a columnar piston 95 movable up and down in the interior of the cylindrical body 93.

  For example, the average value F1 (kPa) of the liquid crosslinking power in step S2 (roll forming step) of Example 1 is determined as follows. First, by accommodating the negative electrode mixture 6 (negative electrode wet granulated body 16) inside the cylindrical body 93, the negative electrode wet granulated body 16 constituting the negative electrode mixture 6 is in contact with the surface 91 b of the flat plate 91. Thereafter, the negative electrode mixture 6 is pressed downward in the vertical direction by the piston 95 to apply a predetermined vertical stress (kPa) to the negative electrode wet granulated body 16 constituting the negative electrode mixture 6. In this state, by moving the flat plate 91 in the horizontal direction (the right direction in FIG. 19), a shear stress is applied to the negative electrode wet granulated body 16 constituting the negative electrode mixture 6, was measured.

  However, as in the roll film-forming apparatus 20 of Example 1, the air AR is sprayed from the air nozzle 61 of the drying apparatus 60 to the surface 91 b of the flat plate 91 to dry the surface 91 b of the flat plate 91 while performing the above-described measurement test. Is going. That is, shear stress (kPa) is measured in a state in which the surface 91 b of the flat plate 91 is dried, as in the case of the surface 1 b of the first roll 1 in the roll forming step of the first embodiment. Furthermore, shear stress (kPa) in each vertical stress (kPa) was measured by varying the vertical stress (kPa) applied to the negative electrode wet granulated body 16 constituting the negative electrode composite 6 by the piston 95. The same applies to the measurement of shear stress (kPa) according to Example 2 described later.

  Thereafter, as shown in FIG. 20, these measurement data are plotted on a coordinate plane with the vertical stress (kPa) as the horizontal axis and the shear stress (kPa) as the vertical axis. Then, these plot data were first-order approximated using the least squares method to obtain a relational expression (linear expression) between the vertical stress (kPa) and the shear stress (kPa) as shown by a straight line in FIG. The y-intercept of this linear expression (straight line) (that is, the value of shear stress when the value of the vertical stress is 0) Average value F1 (kPa) of the liquid crosslinking power between the negative electrode wet granulated body 16 contained in the negative electrode mixture 6 and the surface 1b of the first roll 1 when passing through the gap between the second roll 2 and the second roll 2 " I considered it.

  Similarly to the above, in the roll forming step of Examples 2 to 4 and Comparative Examples 1 and 2, “the negative electrode mixture 6 when the negative electrode mixture 6 passes through the gap between the first roll 1 and the second roll 2 The average value F1 (kPa) of the liquid cross-linking ability between the negative electrode wet granules 16 contained in the first roll 1 and the surface 1b of the first roll 1 or “the positive electrode mixture 36 is the first roll 1 and the second roll 2 The average value F1 (kPa) of the liquid crosslinking power between the positive electrode wet granules 56 contained in the positive electrode mixture 36 and the surface 1b of the first roll 1 when passing through the gap between The results are shown in Table 1.

However, when the average value F1 (kPa) of the liquid crosslinking power according to Examples 3 and 4 is obtained, the surface of the flat plate 91 from the air nozzle 161 of the drying device 160 as in the roll film forming apparatus 120 of Examples 3 and 4. The above-mentioned measurement test is conducted while drying the surface 91b of the flat plate 91 by spraying the dry air DAR onto the 91b. That is, shear stress (kPa) is measured in a state in which the surface 91 b of the flat plate 91 is dried, as in the case of the surface 1 b of the first roll 1 in the roll forming process of Examples 3 and 4. In this measurement test, dry air DAR having a dew point of -30.degree. C. is used as dry air DAR.
Further, when the average value F1 (kPa) of the liquid crosslinking power according to Comparative Examples 1 and 2 is determined, the above-described measurement test is performed without blowing air or the like on the surface 91b of the flat plate 91.

  Furthermore, the test evaluated about the manufacturing method of Examples 5-8 was done. Specifically, using the roll film forming apparatus 220, 320 of each example, a current collecting foil 9 with a film-like negative electrode mixture having a length of 100 m or a current collecting foil 39 with a film-like positive electrode mixture was produced. And, regarding the current collector foil 9 with a film-like negative electrode composite material or the current collector foil 39 with a film-like positive electrode composite material of each example, how many film formation defects (film formation defects) occur in 100 m in length investigated. The results are shown in Table 2.

  Moreover, as a comparative example 3, compared with the roll film-forming apparatus 220 of Example 5, only using the roll film-forming apparatus which differs only in the point which has not provided the wetting apparatus 260, 100 degreeC of film-like negative mix materials A current collector foil 9 was produced. Furthermore, as Comparative Example 4, a film-like positive electrode composite having a length of 100 m using a roll film-forming apparatus which differs from the roll film-forming apparatus 220 of Example 5 only in that the wetting apparatus 260 is not provided. A current collector foil 39 was produced. Also about these, it was investigated how many film-forming defects (film-forming defect) have generate | occur | produced in length 100 m. The results are shown in Table 2.

  Moreover, in the roll forming process of Examples 5 to 8 and Comparative Examples 3 and 4, “The negative electrode mixture 6 is included in the negative electrode mixture 6 when passing through the gap between the first roll 1 and the second roll 2. Average value F2 (kPa) of liquid crosslinking force between the negative electrode wet granulated body 16 and the surface 2b of the second roll 2 or “a gap between the first roll 1 and the second roll 2 of the positive electrode mixture 36 The average value F2 (kPa) of the liquid crosslinking power between the positive electrode wet granulated body 56 contained in the positive electrode mixture 36 and the surface 2b of the second roll 2 when passing through. In the present test, the average value F2 (kPa) of the liquid crosslinking power is determined as follows.

  Specifically, in the same manner as the average value F1 (kPa) of the liquid crosslinking power according to Example 1 and the like described above, the average value of the liquid crosslinking power using the powder layer shear force measuring apparatus 90 (see FIG. 19) F2 (kPa) was determined. In addition, since the surface 1b of the first roll 1 and the surface 2b of the second roll 2 are equivalent surfaces (the surface roughness and the like are equal), in the present test, the surface 1b of the first roll 1 and the second roll 2 The surface 91 b of the flat plate 91 is commonly used as a substitute for the surface 2 b of FIG.

  However, when the average value F2 (kPa) of the liquid crosslinking power according to Examples 5 and 6 is determined, the liquid L1 and L2 contained in the non-woven fabric 261 as in the roll film forming apparatus 220 of Examples 5 and 6 Is attached to the surface 91 b of the flat plate 91 to wet the surface 91 b of the flat plate 91 while performing the above-mentioned measurement test. That is, shear stress (kPa) is measured in a state in which the surface 91 b of the flat plate 91 is wetted, as in the case of the surface 2 b of the second roll 2 in the roll forming step of Examples 5 and 6.

In addition, when the average value F2 (kPa) of the liquid crosslinking power according to Examples 7 and 8 is determined, the liquid L1 and L2 sprayed from the spray nozzle 361 as in the roll film forming apparatus 320 of Examples 7 and 8. Is attached to the surface 91 b of the flat plate 91 to wet the surface 91 b of the flat plate 91 while performing the above-mentioned measurement test. That is, shear stress (kPa) is measured in a state in which the surface 91 b of the flat plate 91 is wetted, as in the case of the surface 2 b of the second roll 2 in the roll forming step of Examples 7 and 8.
In addition, when the average value F2 (kPa) of the liquid crosslinking power according to Comparative Examples 3 and 4 is determined, the above-described measurement test is performed without depositing the liquid on the surface 91b of the flat plate 91.

  After that, in the same way as the average value F1 (kPa) of the liquid crosslinking force described above, each measurement data for each example and comparative example was taken with vertical stress (kPa) as horizontal axis and shear stress (kPa) as vertical axis. Plot in the coordinate plane (see FIG. 20). Then, these plot data were first-order approximated using the least squares method to obtain a relational expression (linear expression) between the vertical stress (kPa) and the shear stress (kPa) as shown by a straight line in FIG. The y-intercept (that is, the value of shear stress when the value of normal stress is 0) of this linear expression (straight line) is the average value F2 of the liquid crosslinking force in step S2 (roll forming step) of each example and comparative example. (KPa). The results are shown in Table 2.

Here, the results shown in Tables 1 and 2 will be examined.
First, the results of Examples 1 to 4 and Comparative Examples 1 and 2 shown in Table 1 will be examined. In Comparative Example 1, the average value F1 of the liquid crosslinking power was 9.3 kPa, and there were also 213 film formation defects (film formation defects). Further, in Comparative Example 2, the average value F1 of the liquid crosslinking power was 6.2 kPa, and there were also 168 deposition defects (deposition defects).

  On the other hand, in Example 1, the average value F1 of the liquid crosslinking power was as small as 2.8 kPa, and the film formation defect (film formation defect) was as small as nine. Further, in Example 2, the average value F1 of the liquid crosslinking power was as small as 1.6 kPa, and the film formation defect (film formation defect) was as small as seven. Furthermore, in Example 3, the average value F1 of the liquid crosslinking power was extremely small at 0.4 kPa, and the film formation defects (film formation defects) were extremely small at two places. Furthermore, in Example 4, the average value F1 of the liquid crosslinking power was extremely small at 0.2 kPa, and the film formation defects (film formation defects) were extremely small at two places.

  As described above, in Examples 1 to 4, film formation defects (film formation defects) could be extremely reduced as compared with Comparative Examples 1 and 2. The reason is that in Examples 1 to 4, as compared with Comparative Examples 1 and 2, the average value F1 of the liquid crosslinking power can be significantly reduced.

  Specifically, in the first and second embodiments, the surface AR of the first roll 1 is dried by spraying the air AR onto the surface 1b of the first roll 1 from the air nozzle 61 of the drying device 60 in the roll forming step. While the negative electrode composite material 6 (negative electrode wet granulated body 16) or the positive electrode composite material 36 (positive electrode wet granulated body 56) is allowed to pass through the gap between the first roll 1 and the second roll 2 This is because the force average value F1 is reduced to satisfy the relationship of F1 <F2 (see FIGS. 1 and 2).

  In the third and fourth embodiments, in the roll forming step, the dry air DAR is sprayed from the air nozzle 161 of the drying device 160 to the surface 1 b of the first roll 1 to dry the surface 1 b of the first roll 1. The composite material 6 (negative electrode wet granulated body 16) or the positive electrode composite material 36 (positive electrode wet granulated body 56) is caused to pass through the gap between the first roll 1 and the second roll 2 to obtain an average of liquid crosslinking ability. This is because the value F1 is significantly reduced to satisfy the relationship of F1 <F2 (see FIGS. 13 and 14).

In addition, it can be said that the value of F2 in Examples 1 and 3 and Comparative Example 1 is equal to the value of F2 in Comparative Example 3. That is, it can be said that F2 = 9.3 (kPa).
Further, it can be said that the value of F2 in Examples 2 and 4 and Comparative Example 2 is equal to the value of F2 in Comparative Example 4. That is, it can be said that F2 = 6.2 (kPa).

  By doing this, in Examples 1 to 4, in the roll forming step, the positive electrode wet granulated body 56 included in the negative electrode wet granulated body 16 included in the negative electrode mixture 6 or the positive electrode wet granulated body 56 included in the positive electrode mixture 36 faces each other. When it passes through the gap between the rotating first roll 1 and the second roll 2, it adheres to the surface 2 b of the second roll 2 having a relatively large liquid crosslinking force among the first roll 1 and the second roll 2. As a result, it can be said that film formation defects (film formation defects) are less likely to occur.

  From the above results, it can be said that film formation defects (film formation defects) are less likely to occur by drying the surface 1 b of the first roll 1 in the roll forming step so as to satisfy the relationship of F1 <F2. Furthermore, in addition to satisfying the relationship of F1 <F2 in the roll forming step, by satisfying the relationship of F1 ≦ 2.8 kPa, film deposition defects (film deposition defects) are extremely unlikely to occur. It can be said that

  The reason why film formation defects (film formation defects) can be reduced in Examples 3 and 4 compared to Examples 1 and 2 is considered as follows. Specifically, in Examples 1 and 2, air AR (air) is sprayed on the surface 1b of the first roll 1, whereas in Examples 3 and 4, the dew point is −30 ° C. or less (described above Since dry air DAR of -30 ° C. is sprayed in the test, it can be said that the surface 1 b of the first roll 1 can be further dried as compared with Examples 1 and 2. As a result, in Examples 3 and 4, F 1 is further reduced compared to Examples 1 and 2, and the cathode wetting in the anode wet granulated body 16 or the cathode composite 36 contained in the anode mixture 6 is performed. It can be said that the granulated bodies 56 are more easily attached by the surface 2 b of the second roll 2, and as a result, film formation defects (film formation defects) are less likely to occur.

  Next, the results of Examples 5 to 8 and Comparative Examples 3 and 4 shown in Table 2 will be examined. In Comparative Example 3, the average value F2 of the liquid crosslinking power was 9.3 kPa, and there were also 213 film formation defects (film formation defects). Further, in Comparative Example 4, the average value F1 of the liquid crosslinking power was 6.2 kPa, and there were also 168 deposition defects (deposition defects).

  On the other hand, in Example 5, the average value F2 of the liquid crosslinking power was as large as 29.1 kPa, and the film formation defects (film formation defects) were extremely small at three places. Further, in Example 6, the average value F2 of the liquid crosslinking power was increased to 13.6 kPa, and the film formation defects (film formation defects) were extremely reduced to 5 places. Furthermore, in Example 7, the average value F2 of the liquid crosslinking power was increased to 19.1 kPa, and the film formation defect (film formation defect) was reduced to 13 points. Furthermore, in Example 8, the average value F2 of the liquid crosslinking power was increased to 12.4 kPa, and the film formation defect (film formation defect) was reduced to 19 points.

  Thus, in Examples 5 to 8, film formation defects (film formation defects) could be extremely reduced as compared with Comparative Examples 3 and 4. The reason is that in Examples 5 to 8, the average value F2 of the liquid crosslinking power can be increased as compared with Comparative Examples 3 and 4.

  Specifically, in Examples 5 and 6, the surface 2b of the second roll 2 is made to adhere to the surface 2b of the second roll 2 using the wetting device 260 in the roll forming step. The negative electrode mixture 6 (negative electrode wet granulated body 16) or the positive electrode mixture 36 (positive electrode wet granulated body 56) is allowed to pass through the gap between the first roll 1 and the second roll 2 while being wetted. This is because the average value F2 of the liquid crosslinking power is increased to satisfy the relationship of F1 <F2 (see FIGS. 15 and 16).

  In Examples 7 and 8, in the roll forming step, the wetting device 360 is used to attach the liquid L1 or L2 to the surface 2b of the second roll 2, thereby wetting the surface 2b of the second roll 2 And the negative electrode composite material 6 (negative electrode wet granulated body 16) or the positive electrode composite material 36 (positive electrode wet granulated body 56) by passing through the gap between the first roll 1 and the second roll 2; The average value F2 of is increased to satisfy the relationship of F1 <F2 (see FIGS. 17 and 18).

In addition, it can be said that the value of F1 in Examples 5 and 7 and Comparative Example 3 is equivalent to the value of F1 in Comparative Example 1. That is, it can be said that F1 = 9.3 (kPa).
Further, it can be said that the value of F1 in Examples 6, 8 and Comparative Example 4 is equivalent to the value of F1 in Comparative Example 2. That is, it can be said that F1 = 6.2 (kPa).

  By doing this, in Examples 5 to 8, in the roll forming step, the positive electrode wet granulated body 56 contained in the negative electrode wet granulated body 16 contained in the negative electrode mixture 6 or the positive electrode wet granulated body 56 contained in the positive electrode mixture 36 faces each other. When it passes through the gap between the rotating first roll 1 and the second roll 2, it adheres to the surface 2 b of the second roll 2 having a relatively large liquid crosslinking force among the first roll 1 and the second roll 2. As a result, it can be said that film formation defects (film formation defects) are less likely to occur.

  From the above results, it can be said that the film formation defect (film formation defect) hardly occurs by wetting the surface 2 b of the second roll 2 in the roll forming step so as to satisfy the relationship of F1 <F2. Furthermore, in the roll forming step, in addition to satisfying the relationship of F1 <F2, by satisfying the relationship of F2 ≧ 12.4 kPa, a film forming defect (film forming defect) hardly occurs. It can be said that

  The reason why the film formation defects (film formation defects) can be reduced in Examples 5 and 6 as compared to Examples 7 and 8 is considered as follows. Specifically, in Examples 7 and 8, the liquids L1 and L2 sprayed from the spray nozzle 361 are adhered to the surface 2b of the second roll 2, while in Examples 5 and 6, the non-woven fabric 261 is By pressing the surface 2 b of the second roll 2, the liquids L 1 and L 2 contained in the non-woven fabric 261 are adhered to the surface 2 b of the second roll 2.

  For this reason, in Examples 5 and 6, it can be said that the surface 2 b of the second roll 2 could be wetted more uniformly than in Examples 7 and 8. Thus, in Examples 5 and 6, the positive electrode wet granulated body 56 contained in the negative electrode wet granulated body 16 contained in the negative electrode mixture 6 or the positive electrode wet granulated body 56 contained in the positive electrode mixture 36 is the second in comparison with Examples 7 and 8. It becomes easy to adhere on the whole surface 2b of the roll 2, and as a result, it can be said that a film-forming defect (film-forming defect) hardly occurs.

  Although the present invention has been described based on the first to eighth embodiments, the present invention is not limited to the first to eighth embodiments, and various modifications may be made without departing from the scope of the present invention. Needless to say.

  For example, in Examples 5 to 8, the liquid L1 equivalent to the solvent 15 contained in the negative electrode mixture 6 or the positive electrode mixture 36 is contained as a liquid to be attached to the surface 2b of the second roll 2 The liquid L2 equivalent to the solvent 35 was used. However, the liquid to be attached to the surface 2b of the second roll 2 is not limited to the liquid equivalent to the solvent contained in the electrode mixture, and may be a liquid that does not cause a chemical reaction with the substance contained in the electrode mixture. For example, any liquid may be used.

1 first roll 1 b surface 2 second roll 2 b surface 6 negative electrode mixture (electrode mixture)
7 Negative electrode current collector foil 8 Film-like negative electrode composite material 9 Current collector foil with film-like negative electrode composite material 13 negative electrode active material (electrode active material)
14, 34 Binder 15, 35 Solvent 16, 16B Negative electrode wet granulated body 18 Negative electrode mixture layer (electrode mixture layer)
19 Negative electrode sheet (electrode sheet)
20, 120, 220, 320 Roll film forming apparatus 33 positive electrode active material (electrode active material)
36 Positive electrode mixture (electrode mixture)
37 positive electrode current collector foil 38 filmy positive electrode mixture 39 current collector foil with filmy positive electrode mixture 48 positive electrode mixture layer (electrode mixture layer)
49 Positive electrode sheet (electrode sheet)
56, 56 B positive electrode wet granulated body 60, 160 drying device 260, 360 wetting device AR air DAR dry air L1, L2 liquid S1, T1 electrode mixture preparation step S2, T2 roll forming step S3, T3 transfer step S4, T4 electrode combination Material layer formation process

Claims (7)

An electrode mixture composed of a plurality of wet granules obtained by granulating a mixture of an electrode active material, a binder and a solvent, a first roll rotating in the opposite direction, and a second roll having a peripheral speed higher than that of the first roll. A roll forming step of causing the electrode mixture in a film shape to adhere to the surface of the second roll by forming the electrode mixture into a film while compressing the electrode mixture by passing through the gap;
A transfer step of transferring the film-like electrode mixture adhering to the surface of the second roll onto the surface of a current collector foil;
An electrode mixture layer forming step of forming an electrode mixture layer on the surface of the current collector foil by drying the film-like electrode mixture transferred onto the surface of the current collector foil;
In a manufacturing method of an electrode sheet which manufactures an electrode sheet which has the above-mentioned electrode compound material layer on the surface of the above-mentioned current collection foil,
In the roll forming process,
When the electrode mixture passes through the gap between the first roll and the second roll, the liquid crosslinking force between the wet granules and the surface of the first roll contained in the electrode mixture The average value F1 (kPa) and the average value F2 (kPa) of the liquid crosslinking power between the wet granulated body contained in the electrode mixture and the surface of the second roll have a relationship of F1 <F2 Method of producing an electrode sheet to be filled. A method of manufacturing an electrode sheet according to claim 1, wherein
In the roll forming process,
By blowing air on the surface of the first roll to dry the surface of the first roll, passing the electrode mixture through the gap between the first roll and the second roll, the condition of F1 <F2 is satisfied. A method of manufacturing an electrode sheet that satisfies the relationship. A method of manufacturing an electrode sheet according to claim 2, wherein
In the roll forming step, a method for producing an electrode sheet, wherein dry air having a dew point of -30 ° C. or less is used as the air sprayed on the surface of the first roll. It is a manufacturing method of the electrode sheet according to any one of claims 1 to 3.
In the roll forming step, a method of manufacturing an electrode sheet satisfying a relationship of F1 ≦ 2.8 kPa. It is a manufacturing method of the electrode sheet according to any one of claims 1 to 4.
In the roll forming process,
By adhering the liquid to the surface of the second roll to wet the surface of the second roll, passing the electrode mixture through the gap between the first roll and the second roll, F1 <F2 A method of manufacturing an electrode sheet to satisfy the relationship of It is a manufacturing method of the electrode sheet according to claim 5,
In the roll forming step, a method for manufacturing an electrode sheet, wherein a liquid equivalent to the solvent contained in the wet granulated body is used as the liquid to be attached to the surface of the second roll. A method of manufacturing an electrode sheet according to claim 5 or 6, wherein
In the said roll forming process, the manufacturing method of the electrode sheet which satisfy | fills the relationship of F2> = 12.4kPa.

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