JP2012038439A - Method of manufacturing wound type electrode body, and wound type electrode body - Google Patents

Abstract

A method of manufacturing a wound electrode body that can be wound without using an adhesive or an adhesive tape, and a wound electrode body.
A strip-shaped positive electrode plate 32 coated with a positive electrode active material and a strip-shaped negative electrode plate 33 coated with a negative electrode active material are wound around a shaft core 20 with a separator 31 therebetween. In the manufacturing method of the rotary electrode body 10, the diffuser 100 is connected to one end of a cylindrical shaft core 20 having a plurality of small through holes 23 on the outer peripheral surface, and the separator 31 is brought into contact with the shaft core 20, thereby the diffuser. 100, the inside of the shaft core 20 is made lower in pressure than the outside so that the outside air is sucked from the through small holes 23 so that the separator 31 is adsorbed in the vicinity of the through small holes 23, and the separator 31 is wound around the shaft core 20. First, the positive electrode plate 32 and the negative electrode plate 33 are wound around the shaft core 20 while being disposed between the separators 31.
[Selection] Figure 4

Description

  The present invention relates to a method for manufacturing a wound electrode body, and more particularly to an attachment structure between a shaft core of a wound electrode body and a separator.

A wound type battery used for a lithium ion secondary battery, etc., forms a positive electrode and a negative electrode by coating an active material on a metal foil to be a positive electrode current collector and a metal foil to be a negative electrode current collector, respectively. Is formed by sandwiching a separator between the negative electrode and the negative electrode, arranging the separator on the outer peripheral side of the negative electrode, and winding the separator in a cylindrical shape.
However, in order to be mounted on an electric vehicle or a hybrid vehicle, a battery having a large capacity and a high output is required.

Patent Document 1 discloses a technique related to a cylindrical lithium ion battery.
Two separators, each coated with acrylic adhesive at the beginning of winding, are wound around the shaft core at least once around the axial center of the cylindrical shaft that serves as the core for the secondary battery. It is 40% or less of the outer peripheral surface area of the shaft core. An adhesive tape may be used instead of the adhesive. Then, a rolled aluminum foil coated with a positive electrode active material to be a positive electrode and a rolled copper foil coated with a negative electrode active material to be a negative electrode are arranged so as to be sandwiched between two separators, respectively. Thus, a lithium ion secondary battery is formed.

JP 2001-126769 A

However, in forming the secondary battery by applying the technique described in Patent Document 1, it is considered that there are problems described below.
A separator is fixed to the shaft core of the secondary battery using an adhesive or an adhesive tape. However, when such a fixing method using an adhesive or a pressure-sensitive adhesive tape is adopted, a process for applying the adhesive or the pressure-sensitive adhesive tape is required, which increases the cost of the secondary battery.
Moreover, there exists a level | step difference around the part which applied the adhesive agent or the adhesive tape because there is thickness of the adhesive agent or adhesive tape used in the case of fixation of this separator. Such a step may cause a difference in tension when winding the separator, the positive electrode, and the negative electrode with a predetermined tension, which may affect the battery performance.
Specifically, battery reaction unevenness due to uneven surface pressure due to the presence of the stepped portion is generated, and lithium is deposited, which may affect the life of the battery.

  Therefore, in order to solve such a problem, the present invention aims to provide a method for manufacturing a wound electrode body that can be wound without using an adhesive or an adhesive tape, and a wound electrode body. .

In order to achieve the above object, a method for manufacturing a wound electrode body according to an aspect of the present invention has the following characteristics.
(1) A method of manufacturing a wound electrode body in which a strip-shaped positive electrode coated with a positive electrode active material and a strip-shaped negative electrode coated with a negative electrode active material are wound around an axis through a separator. In
A plurality of through-holes on the outer peripheral surface, and one end of the shaft core provided with a flow path communicating with the through-holes, connecting a differential pressure generating means to contact the separator with the shaft core; The differential pressure generating means lowers the inside of the shaft core to a pressure lower than the outside, thereby sucking outside air from the through small hole so that the separator is adsorbed in the vicinity of the through small hole, and the separator is moved to the shaft. A winding type electrode body is formed by starting winding around a core and winding the positive electrode and the negative electrode between the separators while winding around the shaft core.

(2) In the manufacturing method of the wound electrode body according to (1),
The positive electrode, the negative electrode, and the separator are wound on the shaft core, and then the shaft core is removed from the wound electrode body.

In order to achieve the above object, the wound electrode body according to the present invention has the following characteristics.
(3) A strip-shaped positive electrode coated with a positive electrode active material, a strip-shaped negative electrode coated with a negative electrode active material, a separator separating the positive electrode and the negative electrode, and a shaft on which the positive electrode, the negative electrode, and the separator are wound. In a wound electrode body having a core,
The shaft core is provided with a plurality of through-holes on the outer peripheral surface and a flow path that communicates with the through-holes and connects a differential pressure generating means at one end, and the separator is adsorbed in the vicinity of the through-holes The separator is wound around the shaft core.

The following operations and effects can be obtained by the method for manufacturing a wound electrode body according to an aspect of the present invention having such characteristics.
The aspect of the invention described in the above (1) is that a strip-shaped positive electrode coated with a positive electrode active material and a strip-shaped negative electrode coated with a negative electrode active material are wound around an axis through a separator. In the manufacturing method of the wound electrode body to be formed, the differential pressure generating means is connected to one end of the shaft core having a plurality of through-holes on the outer peripheral surface and provided with a flow path communicating with the through-holes. The separator is brought into contact with the shaft core, the inside of the shaft core is made lower than the outside by the differential pressure generating means, the outside air is sucked from the small through holes, and the separator is adsorbed in the vicinity of the small through holes. The winding type electrode body is formed by starting winding around the shaft core and winding around the shaft core while arranging the positive electrode and the negative electrode between the separators.

A small through hole communicating with the flow path is provided on the outer peripheral surface of the shaft core having a flow path inside, and the separator is adsorbed to the shaft core by making the pressure inside the shaft lower than the outside by the differential pressure generating means. In this state, the separator, the positive electrode, and the negative electrode can be wound around the shaft core.
Since it is not necessary to use an adhesive or a pressure-sensitive adhesive tape for the shaft core as shown in the prior art, it is possible to prevent a step from being formed around the adhesive or the pressure-sensitive adhesive tape.
As the separator is wound around the shaft core, friction is generated on the surfaces of the separator, the positive electrode, and the negative electrode. If the separator is wound around the shaft core several times, suction by the differential pressure generating means is not required thereafter. It becomes.

As described above, since the separator, the positive electrode, and the negative electrode can be wound around the shaft core without a step, it is possible to suppress the occurrence of the difference in surface pressure as shown in the problem. Therefore, it is possible to prevent a decrease in battery life due to lithium deposition or the like.
In addition, since it is possible to reduce the process of applying the adhesive and attaching the adhesive tape, it is possible to contribute to cost reduction.

The aspect of the invention described in the above (2) is the wound electrode in the method for manufacturing a wound electrode body according to (1), in which the positive electrode, the negative electrode, and the separator are wound on the shaft core. The shaft core is removed from the body.
Since the shaft core and the separator are not fixed with an adhesive or an adhesive tape, an electrode body having no shaft core can be easily manufactured.

Moreover, the following operation | movement and an effect are acquired by the winding type electrode body by the aspect of this invention which has such a characteristic.
The aspect of the invention described in the above (3) includes a strip-shaped positive electrode coated with a positive electrode active material, a strip-shaped negative electrode coated with a negative electrode active material, a separator separating the positive electrode and the negative electrode, and a positive electrode, a negative electrode, and a separator. In the wound electrode body including a wound shaft core, the shaft core includes a plurality of through small holes on the outer peripheral surface, and a flow path that communicates with the through small holes and connects the differential pressure generating means at one end, The separator is wound around the shaft core in a state where the separator is adsorbed in the vicinity of the through hole.

Therefore, the separator can be adsorbed to the shaft core without an adhesive or adhesive tape, and the separator is wound by holding the separator in the vicinity of the small hole in the shaft core, thereby bonding the shaft core and the separator. It becomes possible to form a wound electrode body without bonding with an agent or an adhesive tape.
Accordingly, it is possible to prevent the occurrence of a step due to the use of an adhesive or an adhesive tape for the wound electrode body, and it is possible to prevent a decrease in battery life due to the step.

It is sectional drawing of the winding type electrode body of 1st Embodiment. It is a perspective view of a shaft core of a 1st embodiment. It is a side view of the winding body of 1st Embodiment. It is sectional drawing of the diffuser connected to the axial center of 1st Embodiment. It is a schematic cross section at the time of removing an axial core from a winding body of a 2nd embodiment.

First, a first embodiment of the present invention will be described.
(First embodiment)
FIG. 1 shows a cross-sectional view of a wound electrode body 10 of the first embodiment.
FIG. 2 is a perspective view of the shaft core 20.
The wound electrode body 10 includes an axis 20, a wound body 30, and a battery container 50. The shaft core 20 includes a cylindrical metal pipe portion 22 using an aluminum alloy and a cylindrical resin pipe portion 21 using a resin. A small through hole 23 is provided on the surface of the shaft core 20. The through small hole 23 is connected to an internal space 24 serving as a flow path. The through holes 23 are formed in a plurality of rows with a diameter of about several mm.
In the drawing, the through small holes 23 are provided at equal intervals so as to form two rows on the outer peripheral surface of the shaft core 20, but the intervals may be changed depending on conditions such as force and thickness for holding the separator 31 described later. Does not prevent you from increasing or decreasing the column.

FIG. 3 shows a side view of the wound body 30.
The wound body 30 is formed by winding a separator 31, a positive electrode plate 32, and a negative electrode plate 33 around the shaft core 20 in a plurality of layers.
The separator 31 is a polyolefin resin porous film having fine pores through which lithium ions can pass, and has a thickness of several tens of μm. The positive electrode plate 32 is formed by applying an active material mainly composed of a lithium transition metal oxide such as lithium cobalt oxide on the surface of an aluminum foil having a thickness of several tens of μm. The negative electrode plate 33 is made of a rolled copper foil having a thickness of several tens of μm coated with an active material mainly composed of carbon.

The positive electrode plate 32 and the negative electrode plate 33 are disposed so as to be sandwiched between the separators 31, and the wound body 30 is formed by winding several tens of times.
The battery container 50 is a cylindrical container that wraps the wound body 30, and has a function of sealing the wound body 30 inside in a state where the wound body 30 is provided on the shaft core 20.
In addition, regarding the active material used for the positive electrode plate 32 and the negative electrode plate 33 and the material and thickness used for the separator 31, it does not preclude appropriately adopting various combinations known at present. This is just an example.

Next, the formation process of the wound electrode body 10 will be described.
The separator 31, the positive electrode plate 32, and the negative electrode plate 33 are separately manufactured and wound, prepared as a roll material, and arranged in a winding process.
Then, after the shaft core 20 is fixed to the rotating shaft, one of the openings of the shaft core 20 is closed, and the diffuser 100 is connected to the other as differential pressure generating means.
FIG. 4 shows a cross-sectional view of the diffuser 100 connected to the shaft core 20.
FIG. 4 shows a state in which the vacuum port 101 of the diffuser 100 is connected to the other end of the shaft core 20 whose one end is covered with the sealing plug 150. Due to the structure of the diffuser 100, dry air supplied to the supply port 102 is discharged from the exhaust port 103, and air is also sucked from the vacuum port 101 with this momentum.

By disposing the separator 31 on the outer peripheral surface of the shaft core 20 with air being sucked from the vacuum port 101, the separator 31 is held on the outer peripheral surface of the shaft core 20 by the air sucked from the through hole 23. That is, since the differential pressure is generated between the inside and the outside of the shaft core 20 by the diffuser 100, the separator 31 is adsorbed and held on the outer peripheral surface of the shaft core 20. In this state, the separator 31 is wound around the shaft core 20.
Specifically, the separator 31 is wound around the shaft core 20 by rotating the shaft core 20 by a rotating shaft (not shown) with the diffuser 100 connected. A predetermined tension is applied to the separator 31, and the separator 31 is held against the shaft core 20 against the tension, so that the separator 31 can be wound without being displaced with respect to the shaft core 20. It is.

Further, when the separator 31 is wound one or more times, friction is generated due to the surface contact between the separators 31. Therefore, if the separator 31 is wound several times, the separator 31 can be undissolved as long as tension is applied.
Similarly, the second separator 31 is disposed so as to be adsorbed to the shaft core 20 until the separator 31 is wound a predetermined number of times while sandwiching the positive electrode plate 32 and the negative electrode plate 33 between the separators 31, The winding of the positive electrode plate 32 and the negative electrode plate 33 is continued.
And the winding body 30 is formed by fixing the separator 31 arrange | positioned in an outermost periphery using an adhesive tape etc. As shown in FIG.
Thereafter, the shaft core 20 and the wound body 30 are placed in the battery container 50 and sealed to form the wound electrode body 10.

Since the wound electrode body 10 of the first embodiment has the above-described configuration, the following operations and effects are achieved.
First, it is possible to contribute to extending the life of the wound electrode body 10.
The wound electrode body 10 of the first embodiment includes a strip-shaped positive electrode plate 32 coated with a positive electrode active material and a strip-shaped negative electrode plate 33 coated with a negative electrode active material around a shaft core 20 via a separator 31. In the manufacturing method of the wound electrode body 10 formed by winding, the diffuser 100 is connected to one end of a cylindrical shaft core 20 having a plurality of through-holes 23 on the outer peripheral surface, and the separator 31 is The separator is brought into a state in which the separator 31 is adsorbed in the vicinity of the through hole 23 by bringing the diffuser 100 into contact with the shaft core 20 and lowering the inside of the shaft core 20 with a lower pressure than the outside by the diffuser 100 to suck outside air from the through hole 23. 31 is started to be wound around the shaft core 20, and the positive electrode plate 32 and the negative electrode plate 33 are wound between the separators 31 while being wound around the shaft core 20.

By providing the through hole 23 in the shaft core 20 and connecting the diffuser 100 as a differential pressure generating means, the separator 31 can be adsorbed and held on the shaft core 20 without using an adhesive or an adhesive tape. .
As shown in the problem, when an adhesive or an adhesive tape is used at the start of winding of the separator 31, the separator 31, the positive electrode plate 32, and the negative electrode plate 33 are wound around the tens of turns to surround the adhesive portion. There is a possibility that a step may be formed, and this step may cause deterioration in quality and an effect on the life due to precipitation of lithium or the like.

However, in the wound electrode body 10 of the first embodiment, the separator 31 is held on the shaft core 20 by the differential pressure by the diffuser 100, and the separator 31 is held by the air drawn from the through small hole 23. There is no such step.
In addition, since the shape of the opening part of the through small hole 23 may be transferred to the surface of the separator 31 because it is held by the through small hole 23, compared with a step formed by an adhesive or an adhesive tape. The effect on the performance of the wound electrode body 10 is negligible.
Therefore, it is possible to contribute to the stabilization of the quality of the wound electrode body 10 and the extension of the lifetime.

Moreover, since it is not necessary to hold | maintain the separator 31 between the axis 20 and the winding body 30 using an adhesive agent or an adhesive tape, the application | coating process of an adhesive agent or the sticking process of an adhesive tape is not required, but a winding type It can be expected to reduce the manufacturing cost of the electrode body 10.
When holding the separator 31 with respect to the shaft core 20, the amount of air sucked from the vacuum port 101 of the diffuser 100 and the amount of air sucked from the through small hole 23 formed in the outer peripheral surface of the shaft core 20. Since the adsorption force is determined by the balance of the amounts, it is necessary to determine the opening area and the number of the through small holes 23 with reference to the tension applied to the separator 31.

Next, a second embodiment of the present invention will be described.
(Second Embodiment)
The wound electrode body 10 of the second embodiment is substantially the same as the configuration of the wound electrode body 10 of the first embodiment, but differs in that it does not have the shaft core 20. Different configurations will be described below.
In FIG. 5, the schematic cross section at the time of removing the axial core 20 from the winding body 30 of 2nd Embodiment is shown.
The wound electrode body 10 of the second embodiment starts winding in a state where the separator 31 is held with respect to the shaft core 20 using the diffuser 100 as shown in the first embodiment. After the formation, a step of extracting the shaft core 20 from the inside of the wound body 30 is provided.

Thus, the coreless wound electrode body 10 without the shaft core 20 can be formed.
In forming the wound electrode body 10, since the shaft core 20 and the separator 31 are not joined using an adhesive or an adhesive tape, the differential pressure generating means such as the diffuser 100 is removed from the shaft core 20. The shaft core 20 and the wound body 30 can be separated relatively easily.
In addition, since the shaft core 20 used for the wound electrode body 10 is sufficient as a dummy shaft core unlike the first embodiment, it has a movable part so that it can be easily removed from the wound body 30 or can be disassembled. The shaft core 20 may be used.

Next, a third embodiment of the present invention will be described.
(Third embodiment)
The wound electrode body 10 of the third embodiment is substantially the same as the configuration of the wound electrode body 10 of the first embodiment, but the configuration of the shaft 20 is different. Different parts will be described below.
The shaft core 20 used in the third embodiment uses a cylindrical porous body instead of a hollow material. The porous body is formed by combining a metal porous body formed by sintering or the like and a resin porous body.

Even with the shaft core 20 using such a porous body, it is possible to obtain the same effect as when the cylindrical shaft core 20 of the first embodiment is used.
That is, it is possible to wind the separator 31 while connecting the vacuum port 101 of the diffuser 100 to one end of the shaft core 20 using a porous body and sucking it, and the adhesive between the shaft core 20 and the separator 31. There is no need to dispose a material that causes a thickness such as an adhesive tape. Therefore, it is possible to contribute to extending the life of the wound electrode body 10.

Although the invention has been described according to the present embodiment, the invention is not limited to the embodiment, and by appropriately changing a part of the configuration without departing from the spirit of the invention. It can also be implemented.
For example, in the first embodiment, a cylindrical member is used for the shaft core 20, but the shaft member only needs to be hollow. For example, an elliptical tube or a rectangular tube has a flat shape. Even a cylinder can be substituted for the shaft core. Any structure that can wind the positive electrode plate 32, the negative electrode plate 33, and the separator 31 may be used.

  Further, the shaft core 20 is composed of a cylindrical metal pipe portion 22 using an aluminum alloy and a cylindrical resin pipe portion 21 using a resin, but further preparing a metal pipe using a copper alloy, etc. Does not preclude other configurations. Any member may be used as long as a member for insulation such as the resin pipe portion 21 is disposed so that the positive electrode side and the negative electrode side are not electrically connected. Further, when a porous body is used for the shaft core 20 as shown in the third embodiment, a method of combining a porous body and a pipe is also conceivable as long as the positive electrode side and the negative electrode side are not electrically connected.

DESCRIPTION OF SYMBOLS 10 Winding type electrode body 20 Axis core 21 Resin pipe part 22 Metal pipe part 23 Through small hole 24 Inner space 30 Winding body 31 Separator 32 Positive electrode plate 33 Negative electrode plate 50 Battery container 100 Diffuser 101 Vacuum port 102 Supply port 103 Exhaust port 150 Sealing stopper

Claims (3)

In the method of manufacturing a wound electrode body formed by winding a strip-shaped positive electrode coated with a positive electrode active material and a strip-shaped negative electrode coated with a negative electrode active material around an axis through a separator,
A differential pressure generating means is connected to one end of the shaft core having a plurality of through holes on the outer peripheral surface and provided with a flow path communicating with the through holes.
The separator is brought into contact with the shaft core, and the pressure inside the shaft core is made lower than the outside by the differential pressure generating means, so that outside air is sucked from the through small hole so that the separator is brought close to the through small hole. The adsorbed state is started, and the separator starts to be wound around the shaft core,
A method of manufacturing a wound electrode body, wherein the wound electrode body is formed by winding the positive electrode and the negative electrode between the separators while winding around the axis. In the manufacturing method of the wound electrode body according to claim 1,
After winding the said positive electrode, the said negative electrode, and the said separator to the said shaft core, the said shaft core is extracted from the said wound electrode body, The manufacturing method of the winding type electrode body characterized by the above-mentioned. A strip-shaped positive electrode coated with a positive electrode active material, a strip-shaped negative electrode coated with a negative electrode active material, a separator separating the positive electrode and the negative electrode, and a shaft core on which the positive electrode, the negative electrode, and the separator are wound. In a wound electrode body,
The shaft core includes a plurality of through-holes on an outer peripheral surface, a flow path that communicates with the through-holes and connects a differential pressure generating means at one end,
A wound electrode body, wherein the separator is wound around the shaft core in a state where the separator is adsorbed in the vicinity of the through hole.

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