JP2014060014A - Method of manufacturing electrode for battery and apparatus of manufacturing electrode for battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method and an apparatus of manufacturing an electrode for battery including an active material layer which includes a linear active material pattern, in which a dense active material layer can be formed by pressing the linear active material pattern.SOLUTION: A method of manufacturing the electrode for a battery includes: a coating step for forming a linear active material pattern on a collector body by moving a nozzle for discharging a pasty active material linearly relative to the collector body; a drying step for drying the active material pattern; and a press step for pressing the active material pattern thus dried. In the coating step, the active material is discharged from the nozzle while applying vibration to the nozzle in a direction substantially perpendicular to the length direction of the active material pattern.

Description

  The present invention relates to a method for manufacturing a battery electrode such as a lithium ion secondary battery having an electrolyte layer interposed between active material layers, and a battery electrode manufacturing apparatus.

  Lithium ion secondary batteries composed of positive electrodes, negative electrodes, electrolytes, etc. are lightweight, large capacity, and capable of high-speed charging / discharging, so they are now widely used in mobile devices such as notebook computers and mobile phones, and automobiles. However, various researches have been made to further increase the capacity and charge / discharge at high speed.

  In such a lithium ion secondary battery, a paste-like active material material is applied on a current collector such as an aluminum foil or a copper foil and dried, and then the obtained film-like active material layer has a predetermined density. It is produced by applying a press process. This press working is aimed at densifying the active material layer to improve the electronic conductivity in the electrode finally obtained and the adhesion between the active material layer and the current collector.

  By the way, the reaction between the positive electrode active material and the negative electrode active material contained in the positive electrode and the negative electrode, respectively, and the electrolyte is rate-limiting, but the lithium ion conductivity of the electrolyte is low. Therefore, in order to increase the capacity and charge / discharge at a high speed, the gap between the positive electrode and the negative electrode should be as narrow as possible and the electrode area of the positive electrode and the negative electrode should be as large as possible, especially the positive electrode active material, the negative electrode active material and the electrolyte. It is important to increase the contact area.

  Focusing on this point, for example, in Patent Document 1 (Japanese Patent Laid-Open No. 2011-198596), providing a solid electrolyte secondary battery structure that realizes low cost, high safety, high energy density, and high output is provided. The intended technology has been proposed.

  That is, in the above-mentioned Patent Document 1, “a first active material layer forming step of forming a continuous first active material layer by applying a coating liquid containing a first active material on the surface of a base material; A coating liquid containing a polymer electrolyte is applied to the surface of the laminate in which the first active material layer is laminated on the surface of the base material, and has irregularities that substantially follow the irregularities on the surface of the laminate. An electrolyte layer forming step of forming an electrolyte layer, and a manufacturing method of an all-solid battery characterized by comprising a so-called line and space structure including a linear active material pattern. An active material layer is disclosed.

JP 2011-198596 A

  However, in the case of the active material layer including the linear active material pattern obtained in Patent Document 1, the active material pattern is substantially linear, and the ground contact area with the substrate is small and the aspect ratio is high. However, there is a problem that the press working must be omitted, and a dense active material layer cannot be obtained.

  In view of the above problems, an object of the present invention is a method of manufacturing a battery electrode including an active material layer having a so-called line-and-space structure including a linear active material pattern. The object is to provide a battery electrode manufacturing method and a battery electrode manufacturing apparatus capable of forming a dense active material layer by pressing.

In order to solve the above problems, the present inventors have
An application step of forming a linear active material pattern on the current collector by moving a nozzle for discharging the paste-like active material material in a linear shape relative to the current collector;
A drying step of drying the active material pattern;
A pressing step of pressing the dried active material pattern,
Discharging the active material from the nozzle while applying vibration to the nozzle in a direction substantially perpendicular to the length direction of the active material pattern in the application step;
A battery electrode manufacturing method is provided.

  According to the method for manufacturing a battery electrode of the present invention having such a configuration, a linear active material pattern having a finely meandering shape, that is, a finely meandering wavy active material pattern can be formed. The wavy active material pattern that meanders finely increases the surface area per unit area when viewed from the normal direction with respect to the surface of the current collector. Since it is difficult to press, it can be pressed after the drying process. In the active material layer having a conventional line and space structure, a continuous layer is formed in the length direction of the linear portion and is relatively strong, but the width direction of the linear portion (that is, the linear portion) In a direction substantially perpendicular to the length direction of the layer), the layer is weak because of the space. On the other hand, the active material layer composed of the finely meandering wavy active material pattern of the present invention can be made into a high-density active material layer without impairing the shape and dimensions even after press working. A battery electrode for realizing a battery such as a lithium ion secondary battery having an excellent discharge capacity can be obtained.

In the battery electrode manufacturing method of the present invention, the frequency of the vibration in the coating step is preferably 25 Hz to 10 kHz.
If the frequency of vibration is 25 Hz or more, it is possible to produce an electrode having a finely meandering wavy active material pattern of the present invention in low-speed application, and if it is 10 kHz or less, in high-speed application, It is possible to manufacture an electrode having a finely meandering wavy active material pattern of the present invention.

In the battery electrode manufacturing method of the present invention, it is preferable that the amplitude of the vibration in the coating step is 30 to 400 μm.
If the amplitude of vibration is 30 μm or more, an improvement in strength can be expected even with a fine active material pattern, and if it is 400 μm or less, there is an advantage that it can be reliably applied to a relatively wide active material pattern.

The present invention also provides:
A nozzle that discharges a paste-like active material in a line;
Scanning means for moving the nozzle relative to the current collector to form a linear active material pattern on the current collector;
Drying means for drying the active material pattern formed on the current collector;
A vibration generator for applying vibration to the nozzle;
Including,
A battery electrode manufacturing apparatus is provided.

  According to the battery electrode manufacturing apparatus of the present invention having such a configuration, a linear active material pattern having a finely meandering shape, that is, a finely meandering wavy line active material pattern can be formed. The wavy active material pattern meandering in the direction of the normal surface with respect to the surface of the current collector has an increased surface area per unit area and can collapse or collapse even when force is applied from above. Since it is difficult, press working can be performed after the drying process. The active material layer composed of the finely meandering wavy active material pattern of the present invention can be made into a high-density active material layer without impairing the shape and dimensions even after pressing, and has excellent charge / discharge capacity. A battery electrode for realizing a battery such as a lithium ion secondary battery is obtained.

Moreover, in the battery electrode manufacturing apparatus of the present invention, it is preferable that the vibration generator includes a control unit that can apply a vibration having a frequency of 25 Hz to 10 kHz to the nozzle.
Similarly to the above, if the frequency of vibration is 25 Hz or more, it is possible to manufacture the electrode having the finely meandering wavy active material pattern of the present invention in low-speed coating, and if it is 10 kHz or less. In high-speed coating, it is possible to produce an electrode having a finely meandering wavy active material pattern of the present invention.

Moreover, in the battery electrode manufacturing apparatus of the present invention, it is preferable that the vibration generating device includes a control unit that can apply a vibration having an amplitude of 30 to 400 μm to the nozzle.
Similar to the above, if the amplitude of vibration is 30 μm or more, an improvement in strength can be expected even with a fine active material pattern, and if it is 400 μm or less, it can be reliably applied to a relatively wide active material pattern. There is.

  According to the present invention, there is provided a method for manufacturing a battery electrode including an active material layer having a so-called line-and-space structure including a linear active material pattern, the press working even if the linear active material pattern is provided. It is possible to provide a battery electrode manufacturing method and a battery electrode manufacturing apparatus having a dense active material layer.

It is a schematic longitudinal cross-sectional view of the lithium ion secondary battery manufactured in one Embodiment of this invention. 1 is a schematic perspective view of a structure (negative electrode) 20 in which a negative electrode active material layer pattern 12A composed of a negative electrode active material layer 12 is formed on the surface of a negative electrode current collector 10 in an embodiment of the present invention. It is a schematic enlarged view which shows the detail of the shape of 12 A of negative electrode active material layer patterns which consist of the negative electrode active material layer 12 in one Embodiment of this invention. It is a figure which shows the structure of the negative electrode manufacturing apparatus in one Embodiment of this invention. It is a schematic diagram which shows a mode that the negative electrode active material layer pattern 12A which consists of the negative electrode active material layer 12 is formed by the nozzle dispensing method in one Embodiment of this invention. It is a figure which shows typically a mode that a solid electrolyte layer is formed using the spin coat method in one Embodiment of this invention. It is a figure which shows typically a mode that a positive electrode active material layer is formed using a doctor blade method. It is a schematic longitudinal cross-sectional view of the modification of the lithium ion secondary battery of this invention.

  Hereinafter, embodiments of a battery electrode manufacturing method and a battery electrode manufacturing apparatus according to the present invention will be described with reference to the drawings, but the present invention is not limited thereto. In the following description, the same or corresponding parts are denoted by the same reference numerals, and redundant description may be omitted. Moreover, since the drawings are for conceptual description of the present invention, the dimensions, ratios, or numbers may be exaggerated or simplified as necessary for easy understanding.

(1) Structure of Lithium Ion Secondary Battery In the present embodiment, the present invention will be described in the case of manufacturing a lithium ion secondary battery having the structure shown in FIG. 1 as an example of the present invention. FIG. 1 is a schematic longitudinal sectional view of a lithium ion secondary battery 1 manufactured in the present embodiment. 2 shows a structure obtained when the negative electrode active material layer 12 is formed on the surface of the negative electrode current collector 10 (that is, formed on the surface of the negative electrode current collector 10 and the negative electrode current collector 10). 1 is a perspective view showing a negative electrode 20 including a negative electrode active material layer 12. Further, FIG. 3 is a schematic enlarged view showing details of the shape of the negative electrode active material layer pattern 12A made of the negative electrode active material layer 12 in the present embodiment.

  The lithium ion secondary battery 1 of this embodiment has a structure in which a negative electrode active material layer 12, a solid electrolyte layer 14, a positive electrode active material layer 16, and a positive electrode current collector 18 are laminated in this order on a negative electrode current collector 10. Have. The negative electrode current collector 10 and the negative electrode active material layer 12 constitute a negative electrode, and the positive electrode active material layer 16 and the positive electrode current collector 18 constitute a positive electrode. In this specification, the X, Y, and Z coordinate directions are defined as shown in FIGS.

  As the negative electrode current collector 10, a known material in the technical field to which the present invention belongs can be used, but a metal film such as an aluminum foil or a copper foil may be used. Although not shown, the negative electrode current collector 10 may be formed on the surface of an insulating base material. As such a base material, a flat plate member made of an insulating material may be used. Examples of such an insulating material include resin, glass, ceramics, and the like. The base material may be a flexible flexible substrate.

  In FIG. 1, the negative electrode active material layer 12 has a substantially semicircular cross-sectional shape. However, since the negative electrode active material layer 12 is actually pressed as described later, The upper end portion is formed to be flat to some extent. As shown in FIG. 2, a striped (linear) negative electrode in which a large number of linear negative electrode active material layers 12 extending in the Y direction are arranged at regular intervals on the negative electrode current collector 10. An active material layer pattern (a negative electrode active material layer pattern having a so-called line and space structure) 12A is formed. The negative electrode active material layer 12 has a high aspect ratio and a high height.

  Further, as shown in detail in FIG. 3, the stripe-shaped (line and space structure) negative electrode active material layer pattern 12A arranged in a large number at regular intervals in the X direction is finely meandered, that is, finely meandered. It has a wavy shape. Accordingly, when viewed from the normal direction (Z direction) with respect to the surface of the negative electrode current collector 10, the surface area per unit area is increased, and even if a force is applied from above, the surface does not easily collapse or collapse. The press working after the drying process can be performed. The negative electrode active material layer 12 composed of the finely meandering wavy negative electrode active material pattern of the present embodiment can be made into a high density negative electrode active material layer 12 without impairing the shape and dimensions even after press working. Thus, a negative electrode for realizing the lithium ion secondary battery 1 having excellent charge / discharge capacity can be obtained.

  As will be described later, in the present embodiment, the negative electrode active material is discharged from the nozzle 40 while vibrating the nozzle 40 in a direction (X direction) substantially perpendicular to the length direction of the negative electrode active material pattern 12A. In order to set the vibration frequency to 25 Hz to 10 kHz and the amplitude to 30 to 400 μm, the negative electrode active material layer 12 has 25 to 10,000 wave numbers in 10 cm when the coating speed is 100 m / s.

  Here, since the negative electrode active material layer pattern 12A has a finely meandering shape, that is, a wavy line shape that finely meanders, it is viewed from the normal direction (Z direction) to the surface of the negative electrode current collector 10. In this case, the surface area per unit area is increased because the unit length and the wave number per unit area are increased, and the area of the negative electrode active material layer per unit area is increased.

  The negative electrode active material layer pattern 12A is less likely to collapse or collapse, for example, as shown in FIG. 4, from the position where the negative electrode active material pattern 12A is roll-pressed in the direction of arrow Y1 in FIG. 4 or vice versa. When viewing the direction, in one negative electrode active material pattern, the negative electrode active material pattern is continuously connected also to the direction orthogonal to the direction of the arrow Y1 (X direction in FIG. 3). Further, one negative electrode active material pattern and the pressing roll are in point contact or line contact during pressing (if the pattern is mountain-shaped and the tip is pointed, point contact is made, and if the upper surface of the pattern is flat, the line is contacted. Contact.). In this contact position, in the meandering negative electrode active material pattern, there are many regions where the roll axial direction (width direction, X direction) and the direction in which the negative electrode active material pattern extends obliquely cross (the inflection point of the meander pattern). (Vertex) intersects vertically.) When crossing obliquely in this way, the cross-sectional area in the width direction of the negative electrode active material pattern at the press position becomes larger than that at the vertical crossing (similar to the cross-sectional area becoming large when cut obliquely). As a result, the bottom in the cross section of the negative electrode active material pattern also becomes longer, and the negative electrode active material pattern is less likely to collapse.

As the negative electrode active material contained in the negative electrode active material layer 12, those commonly used in the technical field of the present invention can be used. For example, metals, metal fibers, carbon materials, oxides, nitrides, silicon, silicon compounds, tin , Tin compounds, various alloy materials, and the like. Of these, oxides, carbon materials, silicon, silicon compounds, tin, tin compounds and the like are preferable in view of the capacity density. As the oxide, for example, the _{formula: Li 4/3 Ti 5/3-} x Fe x O 4 lithium titanate represented by (0 ≦ x ≦ 0.2) and the like. Examples of the carbon material include various natural graphite (graphite), coke, graphitizing carbon, carbon fiber, spherical carbon, various artificial graphite, amorphous carbon, and the like. Examples of the silicon compound include a silicon-containing alloy, a silicon-containing inorganic compound, a silicon-containing organic compound, a solid solution, and the like. Specific examples of silicon compounds include silicon oxide represented by SiO _a (0.05 <a <1.95), silicon and Fe, Co, Sb, Bi, Pb, Ni, Cu, Zn, Ge, An alloy containing at least one element selected from In, Sn, and Ti, silicon, silicon oxide, or a part of silicon contained in the alloy is B, Mg, Ni, Ti, Mo, Co, Ca, Cr, Cu, Examples thereof include silicon compounds or silicon-containing alloys substituted with at least one element selected from Fe, Mn, Nb, Ta, V, W, Zn, C, N, and Sn, and solid solutions thereof. Examples of the tin compound include SnO _b (0 <b <2), SnO ₂ , SnSiO ₃ , Ni ₂ Sn ₄ , Mg ₂ Sn, and the like. A negative electrode active material may be used individually by 1 type, and may be used in combination of 2 or more type as needed.

  Moreover, the negative electrode active material layer 12 may contain the conductive support agent. As the conductive auxiliary agent, those commonly used in the technical field of the present invention can be used. For example, natural graphite, graphite such as artificial graphite, acetylene black, ketjen black, channel black, furnace black, lamp black, thermal black Carbon blacks such as carbon fibers, conductive fibers such as carbon fibers and metal fibers, metal powders such as carbon fluoride and aluminum, conductive whiskers such as zinc oxide, conductive metal oxides such as titanium oxide, and phenylene derivatives Organic conductive materials such as A conductive agent can be used individually by 1 type, or can be used in combination of 2 or more type as needed.

  On the upper side of the negative electrode active material layer 12, as shown in FIG. 1, a thin-film solid electrolyte layer 14 having a substantially constant thickness formed by a solid electrolyte is provided. The solid electrolyte layer 14 uniformly covers substantially the entire upper surface of the negative electrode 20 so as to follow the unevenness of the surface of the negative electrode 20 formed by the negative electrode current collector 10 and the negative electrode active material layer 12, and The surface of the solid electrolyte layer 14 also has an uneven shape.

Examples of the solid electrolyte contained in the solid electrolyte layer 14 include polymer electrolyte materials such as resins such as polyethylene oxide and / or polystyrene, and examples of the supporting salt include lithium hexafluorophosphate (LiPF ₆ ). And lithium perchlorate (LiClO ₄ ) and lithium bistrifluoromethanesulfonylimide (LiTFSI). A borate polymer electrolyte may be used. Of course, various additives may be mixed as long as the effects of the present invention are not impaired.

  As shown in FIG. 1, a positive electrode active material layer 16 is provided on the upper side of the solid electrolyte layer 14. The lower surface side of the positive electrode active material layer 16 has a concavo-convex shape along the concavo-convex shape of the upper surface of the solid electrolyte layer 14, but the upper surface side has a substantially flat shape. The positive electrode active material layer 16 also has a high aspect ratio and height in the same manner because the negative electrode active material layer 12 has a high aspect ratio and height as described above.

Examples of the positive electrode active material (powder) included in the positive electrode active material layer 16 include lithium-containing composite metal oxides, chalcogen compounds, and manganese dioxide. The lithium-containing composite metal oxide is a metal oxide containing lithium and a transition metal or a metal oxide in which a part of the transition metal in the metal oxide is substituted with a different element. Here, examples of the different elements include Na, Mg, Sc, Y, Mn, Fe, Co, Ni, Cu, Zn, Al, Cr, Pb, Sb, and B, and Mn, Al, Co, Ni, Mg and the like are preferable. One kind or two or more kinds of different elements may be used. Among these, lithium-containing composite metal oxides can be preferably used. Examples of the lithium-containing composite metal oxide include Li _x CoO ₂ , Li _x NiO ₂ , Li _x MnO ₂ , Li _x Co _y Ni _{1 -y} O ₂ , Li _x Co _y M _{1 -y} O _z , and Li _{x. Ni 1-y M y O z} , Li x Mn 2 O 4, Li x Mn 2-y M y O 4, LiMPO 4, Li 2 MPO 4 F ( in the respective formulas, for example, M is Na, Mg, Sc , Y, Mn, Fe, Co, Ni, Cu, Zn, Al, Cr, Pb, Sb, V and B. At least one selected from the group consisting of 0 <x ≦ 1.2 and 0 <y ≦ 0. 9, 2.0 ≦ z ≦ 2.3), LiMeO ₂ (wherein Me = MxMyMz; Me and M are transition metals, x + y + z = 1), and the like. Specific examples of the lithium-containing composite metal oxide include LiNi _1/3 Mn _1/3 Co _1/3 O ₂ and LiNi _0.8 Co _0.15 Al _0.05 O ₂ . Here, x value which shows the molar ratio of lithium in each said formula increases / decreases by charging / discharging. Examples of the chalcogen compound include titanium disulfide and molybdenum disulfide. A positive electrode active material can be used individually by 1 type, and may use 2 or more types together. The positive electrode active material layer 16 may include the conductive additive described above with respect to the negative electrode active material layer 12.

  Thus, the positive electrode current collector 18 is laminated on the upper surface side of the positive electrode active material layer 16 having a substantially flat shape, and thereby the lithium ion secondary battery 1 is formed. As the positive electrode current collector 18, a material known in the technical field to which the present invention belongs can be used, and any metal film such as a copper foil or an aluminum foil may be used. Although not shown, the positive electrode current collector 18 may be formed on the surface of an insulating base material. As such a base material, a flat plate member made of an insulating material may be used. Examples of such an insulating material include resin, glass, ceramics, and the like. The base material may be a flexible flexible substrate. Although not shown, this lithium ion battery secondary battery 1 may be provided with a tab electrode as appropriate, and a plurality of lithium ion battery secondary batteries 1 are connected in series and / or in parallel. It is good also as an ion secondary battery apparatus.

  The lithium ion secondary battery of this embodiment having such a structure is thin and easy to bend. In addition, since the high-density negative electrode active material layer 12 and the positive electrode active material layer 16 have a three-dimensional structure having irregularities as illustrated, the surface area with respect to the volume is increased, so that the positive electrode through the thin solid electrolyte layer 14 A large contact area facing the active material layer 16 can be secured, and high efficiency and high output can be obtained. Thus, the lithium ion secondary battery 1 of this embodiment is small and has high performance.

(2) Manufacturing Method and Manufacturing Device for Electrode and Lithium Ion Secondary Battery of the Present Embodiment Next, a method for manufacturing the electrode and the lithium ion secondary battery 1 according to the present embodiment will be described. When manufacturing the lithium ion secondary battery 1 of this embodiment, the negative electrode active material layer 12 is formed on the negative electrode current collector 10 shown in FIG. 1, and the negative electrode is formed through a drying step and a pressing step. The solid electrolyte 14 is formed on the upper surface of the negative electrode active material layer 12, and then the positive electrode active material layer 16 and the positive electrode current collector 18 (positive electrode) are formed on the upper surface of the solid electrolyte 14.

(2-1) Negative Electrode First, a method for producing a negative electrode in the present embodiment will be described. The negative electrode of this embodiment is manufactured by the manufacturing method of the battery electrode of the present invention including the following steps (a) to (c).
(A) The nozzle 40 for discharging the paste-like negative electrode active material material in a linear form is moved relative to the long negative electrode current collector 10, and is substantially perpendicular to the length direction of the obtained negative electrode active material pattern 12A. An application step of forming a negative electrode active material pattern 12A composed of a linear negative electrode active material layer 12 on the negative electrode current collector 10 by discharging a negative electrode active material from the nozzle 40 while vibrating the nozzle 40 in the direction;
(A) A drying step of drying the negative electrode active material pattern 12A, and (c) a pressing step of pressing the dried negative electrode active material pattern 12A.

Here, in FIG. 4, the manufacturing apparatus for enforcing the manufacturing method of the negative electrode of this embodiment is shown notionally. As shown in FIG. 4, the negative electrode manufacturing apparatus 100 according to the present embodiment is composed of each part for performing the coating step (a), the drying step (a), and the pressing step (c). . In the application process portion of the negative electrode manufacturing apparatus 100 of the present embodiment, first, the negative electrode current collector 10 from the unwinding roller 30 is conveyed in the direction of arrow Y ₁ by the conveying roller 32 and the conveying roller 34, and the winding roller 50. It has the structure wound up by.

  That is, it can be said that the transport roller 32 and the transport roller 34 are scanning means for moving the nozzle 40 relative to the negative electrode current collector 10. As described above, the active material layer composed of the negative electrode active material layer 12 on the surface of the negative electrode current collector 10 as shown in FIG. 2 before being taken out from the take-out roller 30 and taken up by the take-up roller 50. A pattern 12A is formed.

(A) Application Step A paste-like negative electrode active material is linearly discharged from the nozzle 40 onto the surface of the negative electrode current collector 10 being conveyed. In the present embodiment, the nozzle 40 is fixed, and the negative electrode current collector 10 is conveyed, whereby the nozzle 40 is moved relative to the negative electrode current collector 10.

  A vibration generator 40x is attached to the nozzle 40, and the negative electrode active material is applied from the nozzle 40 while applying vibration to the nozzle 40 in a direction (X direction) substantially perpendicular to the length direction of the negative electrode active material pattern 12A. Discharge. As a result, a negative electrode active material layer pattern 12A having a finely meandering shape, that is, a finely meandering wavy shape as shown in FIG. 3, is formed.

Here, as the vibration generating device 40x, various devices can be used as long as vibration can be applied to the nozzle 40 in a direction (X direction) substantially perpendicular to the length direction of the negative electrode active material pattern 12A. Can be used. For example, a mechanical vibrator or an ultrasonic vibrator can be used.

  Although not shown, the vibration generator 40x is connected to a control device that can apply vibrations having a frequency of 25 Hz to 10 kHz and an amplitude of 30 to 400 μm to the nozzle 40. The vibration generator 40x has a frequency of 25 Hz to 10 kHz and a frequency of 30 Hz. The negative electrode active material is discharged from the nozzle 40 while applying vibration having an amplitude of ˜400 μm to the nozzle 40 to form the negative electrode active material pattern 12 </ b> A composed of the linear negative electrode active material layer 12 on the negative electrode current collector 10. .

  If the frequency of vibration is 25 Hz or more, it is possible to produce an electrode having a finely meandering wavy active material pattern of the present invention in low-speed application, and if it is 10 kHz or less, in high-speed application, It is possible to manufacture an electrode having a finely meandering wavy active material pattern of the present invention. In addition, if the amplitude of vibration is 30 μm or more, strength improvement can be expected even with a fine active material pattern, and if it is 400 μm or less, there is an advantage that it can be reliably applied to a relatively wide active material pattern.

The paste-like negative electrode active material is composed of a mixture obtained by stirring and mixing (kneading) the negative electrode active material, the conductive auxiliary agent, a binder, a solvent, and the like by a conventional method, and a nozzle. In this embodiment, for example, it is preferable that the shear rate is 1 s ⁻¹ and the lower limit is about 10 Pa · s and the upper limit is about 10000 Pa · s. Each component may be dissolved or dispersed in a solvent (including the case where a part is dissolved and the remainder is dispersed).

  Further, the solid content ratio of the negative electrode active material used in the coating process can have various solid content ratios so that the negative electrode active material can be discharged from the nozzle 40, but from the solid content ratio at the wet point of the mixture. Preferably have a small solid content ratio. These viscosities and solid content ratios vary depending on the types and blending amounts, dimensions, shapes, etc. of components such as the negative electrode active material, conductive auxiliary agent, binder and solvent, but the negative electrode active material and the conductive auxiliary agent. And the length of the kneading time when the binder, the solvent and the like are agitated and mixed (kneaded) by a conventional method.

  As the binder, those commonly used in the technical field of the present invention can be used. For example, polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), polyethylene, polypropylene, aramid resin, polyamide, polyimide, polyamideimide , Polyacrylonitrile, polyacrylic acid, polyacrylic acid methyl ester, polyacrylic acid ethyl ester, polyacrylic acid hexyl ester, polymethacrylic acid, polymethacrylic acid methyl ester, polymethacrylic acid ethyl ester, polymethacrylic acid hexyl ester, poly Vinyl acetate, polyvinyl pyrrolidone, polyether, polyether sulfone, polyhexafluoropropylene, styrene-butadiene rubber, ethylene-propylene diene copolymer, carboxymethyl cellulose And the like. Copolymers of monomer compounds selected from tetrafluoroethylene, hexafluoropropylene, perfluoroalkyl vinyl ether, vinylidene fluoride, chlorotrifluoroethylene, ethylene, propylene, pentafluoropropylene, fluoromethyl vinyl ether, acrylic acid, hexadiene, etc. May be used as a binder. A binder can be used individually by 1 type, or can be used in combination of 2 or more type as needed.

As the solvent, it is preferable to use an organic solvent excluding water so as not to decompose lithium hexafluorophosphate (LiPF ₆ ) and the like constituting the solid electrolyte layer 14. As the organic solvent, those commonly used in the technical field of the present invention can be used, and examples thereof include dimethylformamide, dimethylacetamide, methylformamide, N-methyl-2-pyrrolidone (NMP), dimethylamine, acetone, and cyclohexanone. Can be mentioned. An organic solvent can be used individually by 1 type, or can mix and use 2 or more types.

  Here, FIG. 5A schematically shows a state in which the negative electrode active material layer pattern 12A formed of the negative electrode active material layer 12 is formed in the negative electrode active material manufacturing apparatus 100 of the present embodiment shown in FIG. FIG. 5B is a side view (that is, a view seen from a direction substantially parallel to the main surface of the conveyed negative electrode current collector 10), and FIG. 5B is a negative electrode active material layer 12 made of a negative electrode active material layer 12. It is a perspective view showing typically signs that material layer pattern 12A is formed.

In this nozzle dispensing method, a nozzle 40 having one or a plurality of discharge ports (not shown) for discharging a negative electrode active material that is a coating solution is disposed above the negative electrode current collector 10, While discharging a certain amount of the negative electrode active material from the discharge port, the negative electrode current collector 10 is conveyed at a constant speed in the direction of the arrow Y ₁ relative to the nozzle 40. Then, the negative electrode active material is discharged from the nozzle 40 while applying vibration to the nozzle 40 in a direction (X direction) substantially perpendicular to the length direction of the negative electrode active material layer 12.

  Thereby, on the negative electrode collector 10, the some negative electrode active material layer 12 is apply | coated and formed in a fine wavy shape and stripe form along a Y direction. In this embodiment, as shown in FIGS. 1 and 2, since the cross-sectional shape of the negative electrode active material layer 12 is substantially semicircular, the discharge port of the nozzle 40 also has a substantially semicircular shape ( However, the upper portion of the negative electrode active material layer 12 is made substantially planar by the pressing process.

  If a plurality of discharge ports are provided in the nozzle 40, a plurality of negative electrode active material layers 12 can be formed into a stripe shape. By continuing to convey the negative electrode current collector 10, the negative electrode current collection from the unwinding roller 30 can be performed. The negative electrode active material layer 12 can be formed in a stripe shape on the entire surface of the electric body 10.

(A) Drying process Since the striped negative electrode active material layer pattern 12A composed of the plurality of negative electrode active material layers 12 formed as described above is still in the state of a coating film containing a solvent or the like, the negative electrode active material layer The negative electrode current collector 10 provided with the pattern 12A is conveyed so as to pass through the lower region of the drying means 42. In this lower region, a drying process is performed on the negative electrode active material layer pattern 12 </ b> A composed of the plurality of negative electrode active material layers 12 by dry air 44. In addition, what is necessary is just to dry to such an extent that the below-mentioned press work can be given, and it does not necessarily need to dry completely.

  Although the drying temperature of a drying process should just be a range which does not impair the effect of this invention, it should just be the temperature within the range of 5 to 150 degreeC, for example. Further, the drying time of the drying step can be controlled by the conveyance speed of the negative electrode current collector 10, and may be approximately 10 minutes to 24 hours, although it varies depending on the composition of the negative electrode active material layer and the solid content ratio. The drying means 42 may be a conventionally known one, and for example, a blower or a drying furnace using hot air, far infrared rays, or vacuum drying can be used.

(C) Pressing Step In the negative electrode manufacturing apparatus 100 shown in FIG. 4, the negative electrode active material layer 12 (negative electrode active material pattern 12 </ b> A) dried by the drying means 42 is subjected to pressing. In the present embodiment, the negative electrode current collector 10 on which the negative electrode active material layer 12 (negative electrode active material pattern 12A) is formed is sandwiched between the upper roller 46a and the lower roller 46b, and the upper roller 46a and the lower roller 46b. Pressing is performed by passing between them.

  The conditions such as pressing pressure and time in this case may be determined within a range in which the shape of the negative electrode active material layer 12 (negative electrode active material pattern 12A) is not impaired and the electrode density can be improved.

  At this time, the upper surface of the negative electrode active material layer 12 that is raised with respect to the surface of the substantially flat negative electrode current collector 10 is substantially flat (flat), and the negative electrode active material has a fine wavy shape. Layer 12 is formed. Therefore, the surface area with respect to the usage amount of the negative electrode active material can be increased, and the facing area with the positive electrode active material layer to be formed later can be increased to realize a large capacity.

(2-2) Solid Electrolyte Layer As a method for forming the solid electrolyte layer 14 on the upper surface of the negative electrode 20 composed of the negative electrode current collector 10 and the negative electrode active material layer 12 as described above, a conventionally known method is adopted. Although not particularly limited, in the present embodiment, the solid electrolyte layer 14 is formed by applying a solid electrolyte material, for example, by spin coating.

  FIG. 6 is a diagram schematically showing the state of application of the solid electrolyte material by spin coating in the present embodiment. As shown in FIG. 6, the negative electrode 20 formed by laminating the negative electrode current collector 10 and the negative electrode active material layer 12 is a rotary stage that is rotatable around a rotation axis in the vertical direction (Z direction) in a predetermined rotation direction Dr. 60 is mounted substantially horizontally.

  Therefore, in the present embodiment, the negative electrode composed of the negative electrode current collector 10 on which the negative electrode active material layer 12 is formed can be placed on the rotary stage 60 in a direction substantially perpendicular to the length direction of the negative electrode current collector 10. After cutting into dimensions, the solid electrolyte layer 14 is formed.

  The rotary stage 60 rotates at a predetermined rotational speed, and a paste-like solid electrolyte material 64 as a coating solution is discharged toward the negative electrode 20 from a nozzle 62 provided at an upper position on the rotary shaft of the rotary stage 60. . The solid electrolyte material dropped on the upper surface of the negative electrode 20 gradually spreads around by the centrifugal force of the rotating rotary stage 60, and excess solid electrolyte material is blown off from the end of the negative electrode 20.

  With such a mechanism, the upper surface of the negative electrode 20 is thinly and uniformly covered with the solid electrolyte material, and the solid electrolyte layer 14 can be formed by drying and curing this. What is necessary is just to select suitably according to a conventionally well-known method about the composition of a solid electrolyte material to be used, a viscosity and solid content ratio, and the conditions of dry hardening in the range which does not impair the effect of this invention.

  In the spin coating method, the thickness of the solid electrolyte layer 14 to be obtained can be controlled by the viscosity of the solid electrolyte material and the rotation speed of the rotary stage 60, and the surface is uneven as in the negative electrode 20 in the present embodiment. A thin-film solid electrolyte layer 14 having a uniform film thickness can be formed along the unevenness even on an object to be coated.

  The thickness of the solid electrolyte layer 14 is arbitrary, but it is necessary that the negative electrode active material layer 12 and the positive electrode active material layer 16 be reliably separated from each other and that the internal resistance be not too high. is there. In order not to impair the effect of the increased surface area by providing irregularities on the negative electrode active material layer 12, the thickness t14 of the solid electrolyte layer 14 (symbol t14 in FIG. 1) and the irregularities of the negative electrode active material layer 12 It is desirable that the height difference t12 (symbol t12 in FIG. 1) satisfies the relational expression: t14 <t12.

(2-3) Positive Electrode A method of forming the positive electrode active material layer 16 on the upper surface of the laminate 70 formed by laminating the negative electrode current collector 10, the negative electrode active material layer 12, and the solid electrolyte layer 14 formed as described above. In the present embodiment, a positive electrode active material layer 16 is applied by applying a paste-like positive electrode active material by, for example, a doctor blade method. Form.

  As the positive electrode active material, a material obtained by stirring and mixing (kneading) the above-described positive electrode active material, conductive additive, binder, solvent and the like can be used. What is necessary is just to select suitably according to a conventionally well-known method about the viscosity and solid content ratio, and the conditions of dry hardening in the range which does not impair the effect of this invention.

  FIG. 7 is a diagram schematically showing a state of application of the positive electrode active material by the doctor blade method. More specifically, FIG. 7A is a side view schematically showing that the positive electrode active material layer 16 is formed by applying the positive electrode active material on the upper surface of the laminate 70 by the doctor blade method (that is, 7 (b) is a view seen from a direction substantially parallel to the main surface of the negative electrode current collector 10 having the negative electrode active material layer 12, and FIG. 7 (b) shows a case where the positive electrode active material is applied and the positive electrode active material is applied. It is a perspective view which shows a mode that the material layer 16 is formed typically.

The nozzle 72 that discharges the positive electrode active material is scanned and moved relative to the stacked body 70 in the direction indicated by the arrow Y ₂ . In the moving direction Y ₂ of the nozzle 72, a doctor blade 74 is attached to the rear side of the nozzle 70, and the lower end of the doctor blade 74 is located above the solid electrolyte layer 14 formed on the upper surface of the laminate 70. Since the upper surface of the discharged positive electrode active material is in contact, the positive electrode active material layer 16 having a flat upper surface can be obtained.

The nozzle 72 used in this step may be a nozzle having a large number of ejection openings like the nozzle 40 shown in FIG. 5, or extends in a direction perpendicular to the moving direction Y ₂ (that is, the direction of the arrow X). A nozzle having a slit-like discharge port may be used.

  In this way, by applying the positive electrode active material to the laminate 70, the positive electrode active material layer 16 having an unevenness along the unevenness of the solid electrolyte layer 14 on the lower surface and a substantially flat upper surface is formed on the laminate 70. Can be formed on the upper surface of the substrate.

  By laminating the positive electrode current collector 18 on the upper surface of the positive electrode active material layer 16 formed as described above, the lithium ion secondary battery 1 of the present embodiment having the structure shown in FIG. 1 can be obtained. . As the positive electrode current collector 18, a conventionally known material can be used, and for example, a metal foil such as a copper foil can be used.

  At this time, it is preferable to stack the positive electrode current collector 18 before the positive electrode active material layer 16 is cured, because the positive electrode active material layer 16 and the positive electrode current collector 18 can be brought into close contact with each other and bonded. Moreover, since the upper surface of the positive electrode active material layer 16 is substantially flat, the positive electrode current collector 18 can be stacked without any gap.

≪Deformation mode≫
As mentioned above, although an example of embodiment of this invention was demonstrated, this invention is not limited only to these, A various change besides what was mentioned above is possible unless it deviates from the meaning. For example, in the above embodiment, the negative electrode active material layer 12 is formed first, and the case where the coating process, the drying process, and the pressing process are used only in the formation has been described. However, the positive electrode active material layer 16 is formed first. In addition, a coating process, a drying process, and a pressing process may be used for the formation.

  When the positive electrode active material layer is formed by a coating process, a drying process, and a pressing process according to the electrode manufacturing method of the present invention, the same conditions as those for the negative electrode active material layer may be employed.

  Moreover, in the said embodiment, although the application | coating process, the drying process, and the press process were demonstrated only in formation of the negative electrode active material layer 12, all of the negative electrode active material layer 12 and the positive electrode active material layer 16 were apply | coated. You may form using a process, a drying process, and a press process.

  Moreover, in the said embodiment, after forming the negative electrode active material layer 12 by the application | coating process, after performing a drying process and a press process continuously, the solid electrolyte layer 14, the positive electrode active material layer 16, and the positive electrode collector 18 are carried out. However, after the drying process, the second drying process may be performed after the solid electrolyte layer 14, the positive electrode active material layer 16, and the positive electrode current collector 18 are provided.

  Further, in the above embodiment, in the negative electrode manufacturing method of the present invention, the case where the drying step after the coating step is performed by the drying means has been described, but it may be naturally dried without using the drying means, Vacuum drying may be performed.

  In the above embodiment, the drawing pattern of the negative electrode active material layer 12 on the negative electrode current collector 10 has a so-called line-and-space structure composed of a plurality of stripes arranged at regular intervals. It is not limited. In the above embodiment, the case where the cross-sectional shape of the negative electrode active material layer 12 immediately after application (before pressing) is substantially semicircular has been described. However, the present invention is not limited to this, and is square, rectangular or trapezoidal. It may be a substantially rectangular shape.

  Since the application by the nozzle dispensing method is applied to the formation of the negative electrode active material layer 12 that needs to form a concavo-convex pattern, various patterns can be formed in a short time. Also, the nozzle dispensing method can be suitably applied to the creation of a fine pattern. In this manufacturing method, it is only necessary to create a fine pattern only in the first coating step, that is, the coating step of the active material coating solution. If the uniform coating can be performed in the subsequent coating step, the fine pattern is sufficient. No production is required.

  For example, the coating method applied in each step is not limited to the above, and other coating methods may be applied as long as they meet the purpose of the step. For example, in the above-described embodiment, the spin coating method is applied to form the solid electrolyte layer 14, but any other method can be used as long as it can form a thin film that follows the unevenness of the surface to be coated. For example, the solid electrolyte material may be applied by a spray coating method.

  Further, for example, in the above embodiment, the doctor blade method is applied to form the positive electrode active material layer 16, but the lower surface in contact with the surface to be coated follows the unevenness, and the upper surface may be finished to be substantially flat. Any other application method may be used as long as it is possible. In order to achieve such an object, it is desirable that the viscosity of the positive electrode active material is not so high. In other words, if the viscosity of the positive electrode active material is appropriately selected, the lower surface can be removed without using a doctor blade. It is possible to finish the unevenness and to make the upper surface substantially flat. For example, it may be applied by a nozzle dispensing method, a slit coating method, a bar coating method, or the like.

  In the above-described embodiment, the case where the all-solid-state lithium ion secondary battery having the structure shown in FIG. 1 is manufactured has been described. However, the present invention is not limited thereto, and the present invention is not limited to a linear active material layer (active material As long as it has a pattern), it can also be applied to the production of lithium ion secondary batteries having various structures.

  For example, the present invention can be applied as a method for manufacturing a lithium ion secondary battery having the structure shown in FIG. FIG. 8 is a schematic longitudinal sectional view of a lithium ion secondary battery manufactured in a modified embodiment of the present invention. In the lithium ion secondary battery 201 shown in FIG. 8, the negative electrode active material layer 112 is provided on one surface (the upper surface in FIG. 8) of the negative electrode current collector 110 by the battery electrode manufacturing method of the present invention. Thus, the negative electrode is configured. Moreover, the positive electrode active material layer 116 is provided on one surface (the lower surface in FIG. 8) of the positive electrode current collector 118 by the battery electrode manufacturing method of the present invention to constitute a positive electrode.

  Then, the negative electrode (the negative electrode active material layer 112 and the negative electrode current collector 110) and the positive electrode (the positive electrode active material layer 116 and the positive electrode current collector 118) are placed facing each other with a spacer 202 made of, for example, an insulating material. The lithium ion secondary is injected into the internal space formed by the negative electrode current collector 110, the spacer 202, and the positive electrode current collector 118, and the battery can is sealed after being put in the battery can. A battery 201 is configured. A separator may be interposed in the internal space.

1,201 ... Lithium ion secondary battery,
10, 110 ... negative electrode current collector,
12, 112 ... negative electrode active material layer,
12A ... negative electrode active material layer pattern,
14 ... solid electrolyte layer,
16, 116 ... positive electrode active material layer,
18, 118 ... positive electrode current collector,
20 ... Structure (negative electrode),
20A ... sheet-like negative electrode,
30 ... Unwinding roller,
32 ... Conveying roller,
34, 34a, 34b ... conveying rollers,
36 ... take-up roller,
36a, 36b ... conveying rollers,
38a, 38b ... conveying rollers,
40 ... Nozzle,
40x ... Vibration generator,
42 ... drying means,
44 ... Dry air,
46a, 46b ... rollers,
50 ... Rolled negative electrode,
52 ... heating and drying furnace,
60 ... rotary stage,
62 ... Nozzle,
64 ... Solid electrolyte material,
70: Structure,
72 ... Nozzle,
74 ... Doctor blade,
114 ... electrolyte,
202: Spacer.

Claims (6)

An application step of forming a linear active material pattern on the current collector by moving a nozzle for discharging the paste-like active material material in a linear shape relative to the current collector;
A drying step of drying the active material pattern;
A pressing step of pressing the dried active material pattern,
Discharging the active material from the nozzle while applying vibration to the nozzle in a direction substantially perpendicular to the length direction of the active material pattern in the application step;
A method for producing an electrode for a battery. In the coating step, the vibration frequency is 25 Hz to 10 kHz.
The battery electrode manufacturing method according to claim 1, wherein: In the coating step, the vibration amplitude is 30 to 400 μm,
The battery electrode manufacturing method according to claim 1, wherein: A nozzle that discharges a paste-like active material in a line;
Scanning means for moving the nozzle relative to the current collector to form a linear active material pattern on the current collector;
Drying means for drying the active material pattern formed on the current collector;
A vibration generator for applying vibration to the nozzle;
Including,
A battery electrode manufacturing apparatus. The vibration generating device includes a control unit capable of applying a vibration having a frequency of 25 Hz to 10 kHz to the nozzle;
The battery electrode manufacturing apparatus according to claim 4. The vibration generator includes a control unit capable of applying vibration with an amplitude of 30 to 400 μm to the nozzle;
The battery electrode manufacturing apparatus according to claim 4 or 5.

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