JPH11176447A - Battery and manufacture thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electrode constitution, and a battery manufacturing method for reducing electrode winding shifting in a winding type battery. SOLUTION: For a positive electrode 8 and a negative electrode 9, collectors 80, 90 respectively comprising active material attachment zones 8a, 9a and non-attachment zones 8b, 9b are formed by rolling and pressing, and they are wound around a shaft core 2 via a separator 10. The electrodes 8, 9 are welded with end plates 13, 14 at the non-attachment zones 8b, 9b of the collectors 80, 90 extended along a winding direction to be continuous with a positive electrode terminal 3 and a negative electrode terminal 4. In the non-attachment zones 8b, 9b, plural slits 11 and holes 12 are formed to absorb electrode strain stresses.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a battery provided with an electrode formed by winding a current collector having an electrode active material attached thereto, and a method of manufacturing the battery.

[0002]

2. Description of the Related Art In a battery provided with an electrode formed by winding a current collector to which an electrode active material is attached (hereinafter referred to as a wound battery), a conventional method is used to transfer electrons to and from the battery electrode. For example, a rectangular metal foil is used as a current collector, an electrode obtained by attaching an electrode active material to the current collector is formed into a cylindrically wound electrode. The structure is such that lead wires made of are connected and connected to positive and negative terminals.

However, according to this method, when a large current flows, the resistance of the lead portion increases and the current concentrates on a portion close to the lead wire. However, there is a problem that the battery characteristics such as these deteriorate. In order to solve this problem, instead of attaching a lead wire to the current collector, the end of the metal foil of the current collector is used as a lead portion, and the upper and lower end surfaces of the wound current collector are formed. By welding to a metal plate or the like conducting to the positive and negative terminals, the resistance is reduced and the current distribution is made uniform.

[0004]

By the way, the electrode used in this method has a problem that the welding conditions at the time of welding at the end face cause the current collector to have an edge portion along the winding direction of the metal foil.
It is necessary to expose the metal part at least 2-3 mm from the end. As a method for manufacturing such an electrode, a method in which an active material (electrode material) is attached to a current collector and then the active material is peeled off only at a necessary portion, and a method in which an unattached portion is provided on the current collector when the active material is attached There is.

In the former method of removing the active material, the active material is firmly adhered to the current collector in order to prevent the cycle characteristics of the battery from being deteriorated if the adhesion to the active material is poor. It is considered that removing the strongly adhered active material is inefficient and is not suitable for mass production. On the other hand, in the method of providing an unattached portion on the current collector when the active material is attached, FIG.
As shown in FIG. 6, an active material attaching region 8a and a non-adhering region 8b are provided on a current collector 80 made of a metal foil, and the active material is applied by a coating member (comma coater) P1.
As shown in (b), rolling (press molding) is performed by a roll press P2 to improve the adhesive strength of the active material and the electrode density, and then cutting is performed. Then, FIG. 4 (a)
The electrode 8 is formed as shown in FIG.

[0006] Then, the electrode 8 is wound and assembled into a battery. At the time of winding, a winding shift occurs, and FIG.
As shown in (b), when the wound electrode 8 is assembled to the battery, the cylindrical end faces of the wound electrode 8 are not aligned in a plane, and a displacement (hereinafter referred to as a winding displacement) y occurs. By the way, FIG.
In (b), electrode 8 is a positive electrode, 9 is a negative electrode, 2 is a shaft core, 1
Although 0 indicates a separator, the sign may be reversed.

Such a winding deviation y is large (for example,
For example, the contact between the metal end plate that does not fit in the battery container or the metal end plate that conducts to the terminals of the positive and negative electrodes and the cylindrical end surface of the wound electrode 8 becomes non-uniform, and welding of the two is performed well. Problems such as not going will occur. Therefore, the smaller the winding deviation y, the better. The present inventors have studied the cause of the winding deviation y. As a result, in the above-mentioned rolling process, since the adhering region 8a and the non-adhering region 8b exist on the current collector 80, the difference in elongation between the two regions 8a and 8b during the rolling causes the difference as shown in FIG. It was found that the reason was that the electrode 8 itself was bent in an arc shape in the winding direction in the plane of the current collector 80 after rolling. When the electrode 8 having a large arc-shaped warp x is wound, the winding deviation y becomes large.

SUMMARY OF THE INVENTION In view of the above, it is an object of the present invention to provide an electrode configuration and a method of manufacturing a battery in a wound type battery, which reduce the winding deviation of the electrodes.

[0009]

Means for Solving the Problems The inventors of the present invention have developed an electrode formed by winding a current collector having a lead portion integrated therein, and having the current collector absorb the distortion caused by the arc-shaped warp x. Focusing on providing the absorbing section, the following technical means were adopted. That is, according to the first aspect of the present invention, the region (8) where the electrode active material is
a, 9a) and an electrode formed by winding a current collector (80, 90) formed by rolling a conductive foil having non-adhered regions (8b, 9b) to which no electrode active material is adhered. (8,
9), and the non-adhesion regions (8b, 9b) are provided with a current collector (8b).
0, 90) extending along the winding direction (81,
91), the edges (81, 9)
1) is characterized in that notches (11, 12) for absorbing distortion are formed.

Accordingly, the stress of the arc-shaped warp can be reduced by absorbing the stress in the notches (11, 12). Therefore, it is possible to provide a wound type battery in which winding deviations in the wound electrodes (8, 9) are reduced. Here, the notch is formed by the edge (81,
The slit (11) cut from the outer peripheral edge (82, 92) of the foil at 91) and the void formed inside the outer peripheral edge (82, 92) of the foil at the edge (81, 91). It can be composed of at least one of the holes (12).

When such slits (11) and holes (12) are formed in the current collectors (80, 90), the slits (11) and holes (12) pass through the electrolytic solution, and There is an additional effect that the liquid injection time and the aging time can be reduced. According to a third aspect of the present invention, in the slit (11) and the hole (12) according to the second aspect, the hole (12) is formed at an end point of the cut of the slit (11). . Thereby, the cut of the slit (11) stops at the hole (12),
It is possible to prevent the slit (11) from being extended more than necessary, and it is possible to improve the strength.

According to the study by the present inventors, the slit (11) has a cut length shorter than the width of the non-adhesion regions (8b, 9b) as in the invention according to claim 4. It was found that there was a sufficient effect of absorbing the strain.
The invention described in claim 5 has been made on a method of manufacturing a battery to achieve the object of the present invention.

That is, a conductive foil having an adhesion area (8a, 9a) where the electrode active material is adhered on the same surface of the battery and a non-adhesion area (8b, 9b) where the electrode active material is not adhered is rolled. Electrodes (8, 9) formed by winding the current collectors (80, 90) formed in such a manner that the non-adhesion regions (8b, 9b) are wound in the winding direction of the current collectors (80, 90). A method for manufacturing a battery provided at edges (81, 91) extending along the electrode, wherein an electrode active material is adhered to a foil, and an adhered area (8a, 9a) and a non-adhered area (8b, 9b) Forming a current collector (80, 90) having: and a current collector (80, 9) having both of these regions (8a, 9a, 8b, 9b).
0), forming notches (11, 12) at the edges (81, 91) for absorbing distortion, and both regions (8a, 9).
a, a step of rolling a current collector (80, 90) having a, 8b, 9b) and a step of winding the current collector (80, 90).

Here, the step of forming the notches (11, 12) may be performed before or after the rolling step. When the notches (11, 12) are formed before the rolling step, in the rolling step, the adhering areas (8a, 9a) and the non-adhering areas (8
The notch (11, 12) absorbs the distortion due to the difference in the elongation of the material from that of b, 9b), so that the arc-shaped warpage can be reduced. Therefore, it is possible to provide a wound battery in which winding deviation is reduced during winding.

On the other hand, after the rolling step, the notch (11, 1
When 2) is formed, the above-mentioned arc-shaped warpage stress generated in the rolling step can be absorbed by the cutouts (11, 12) to correct the electrode shape, thereby providing a wound type battery with reduced winding deviation. can do. In addition, the code | symbol in the parenthesis of each said means shows the correspondence with the concrete means of embodiment mentioned later.

[0016]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing a first embodiment of the present invention. The description will be made assuming that the wound type battery according to the present embodiment is applied to a lithium ion secondary battery. FIG.
The following shows the structure of the lithium ion secondary battery. Reference numeral 1 denotes a metal cylindrical container which defines a battery main body. Reference numeral 2 denotes a shaft core, which is disposed at the center of the container and serves as a core when winding the electrode. The shaft core 2 is configured so that the positive terminal 3 and the negative terminal 4 are connected to each other so as to be insulated from each other via the insulating portion 5. And each terminal 3, 4
Used as contacts with external terminals when using batteries. In addition, a hole 2a for injecting an electrolytic solution, which will be described later, is formed in the shaft core 2 (not shown in FIG. 1; see FIG. 5).

Reference numerals 6 and 7 denote plugs, which are inserted into the openings 3a and 4a of the terminals 3 and 4, respectively.
4a is sealed. The openings 3a and 4a of the terminals 3 and 4 serve as electrolyte injection holes.
Sealed with stoppers 6 and 7. Reference numeral 8 denotes a positive electrode, and LiMn ₂ O ₄ , LiN
A positive electrode active material such as iO ₂ or LiCoO ₂ is attached. Reference numeral 9 denotes a negative electrode in which a negative electrode active material of carbon-based particles such as graphite is adhered to a current collector 90 such as a metal foil (for example, a Cu foil).

The positive electrode 8 and the negative electrode 9 are wound around the shaft core 2 with a separator (for example, a polyethylene porous film) 10 for electrically insulating the electrodes 8 and 9 interposed between the electrodes 8 and 9. And stored in the container 1. Positive electrode 8
Has an attached region (hatched portion) 8a to which the positive electrode active material is attached and a non-attached region (non-hatched portion) 8b to which the cathode active material is not attached. The non-adhesion region 8b is provided with a current collector 80 along the winding direction.
At a predetermined width (for example, at least 2 to 3 mm) from the outer peripheral end 82 of the current collector. In the present embodiment, the non-adhesion region 8b and the edge 81
Matches.

The edge 81, that is, the non-adhesion region 8b
Are formed with a plurality of slits 11 and holes 12 along the winding direction, and are formed as cutouts for absorbing distortion. The slit 11 is formed by being cut from the outer peripheral end 82, and the hole 12 is formed as a circular hole at the end point of the cut of each slit 11 (that is, inside the outer peripheral end 82).

The notch may be only the slit 11 and only the hole 12. Here, slit 1
The present inventors also examined the sizes of the holes 1 and the holes 12 and the arrangement interval (the arrangement interval when arranged along the winding direction). Regarding the diameter of the circular hole 12, the edge 81
Although it depends on the width of the (non-adhesion area 8b), the diameter is 1 mm to 2 mm.
It is preferably 0 mm, and if it is smaller than 1 mm, the strain absorption is not sufficiently exhibited, and if it is larger than 20 mm, the edge 8
1 becomes weaker in strength, and a positive electrode side end plate 1
Failures such as deformation at the time of joining with No. 3 occur.

When only the slits 11 are provided, the arrangement interval is preferably in the range of 5 mm to 200 mm. When only the holes 12 are provided, the arrangement interval is 3 mm to 20 mm.
mm. The grounds are the same as the grounds for the above-described preferable range of the diameter of the hole 12. If the interval between the slits 11 or the holes 12 is too small, the edge 8
1 was weakened in strength, and too large, strain absorption was not sufficiently exhibited.

In the present embodiment, the slit 11 and the hole 1
Although both of the two are provided, the arrangement interval is determined based on the knowledge of the respective preferable arrangement interval ranges described above.
It is decided. For example, the hole 12 has a diameter of about φ6 mm, and the arrangement interval between the slit 11 and the hole 12 is 60 mm.
And The negative electrode 9 has an attachment region (hatched portion) 9a to which the anode active material is attached and a non-attached region (non-hatched portion) 9b to which the anode active material is not attached, on both surfaces of the current collector 90. The non-adhesion region 9b is a predetermined width (for example, at least 2-3 mm) from the outer peripheral end 92 of the current collector at the edge 91 of the current collector 90 along the winding direction.
It is provided with. In the present embodiment, the non-adhesion region 9b and the edge 91 match.

The edge 91, that is, the non-adhesion region 9b
Are formed with a plurality of slits 11 and holes 12 as notches similar to those formed in the edge 81 of the positive electrode 8. Further, the positive electrode 8 is provided at the outer peripheral end 82 of the edge portion 81 with the positive electrode side end face plate 1 electrically connected to the positive electrode terminal 3.
The negative electrode 9 is welded to the negative-electrode-side end face plate 14 that is connected to the negative electrode terminal 4 at the outer peripheral end 92 of the edge 91. That is, both poles 8 and 9 have edges 81 and 9
Reference numeral 1 denotes a lead portion for taking out electric charges, and the lead portion has no active material attached thereto.

Reference numerals 15 and 16 denote lids, each of which is a container 1.
The opening on the positive electrode terminal 3 side and the opening on the negative electrode terminal 4 side are closed, and the internal electrolytic solution is sealed. Gaskets 17 and 18 are interposed between the positive electrode terminal 3 and the lid 15 and between the negative electrode terminal 4 and the lid 16 for insulation. In the above configuration, when the battery is used, electrons from the positive electrode 8 are extracted from the edge portion 81 to the positive electrode side end plate 13 and the positive electrode terminal 3 and passed through an external load to the negative electrode terminal 4, the negative electrode side end plate 14 and the edge portion 91. To the negative electrode 4.

Next, a method for manufacturing the battery according to the present embodiment will be described with reference to FIGS. 2A and 2B are process diagrams of a method for manufacturing a battery according to the present embodiment. FIG. 2A illustrates a case where a notch forming step S3 is performed after a rolling step S2, and FIG. 2B illustrates a notch forming step before a rolling step S2. This represents the case where S3 is performed. FIG. 3 is an explanatory diagram illustrating the method for manufacturing the battery of the present embodiment.

In the process shown in FIG.
Steps S2, S3, and S4 are performed similarly for the positive electrode 8 and the negative electrode 9. In FIG. 3, the symbols outside the parentheses indicate the positive electrode 8.
The figures in parentheses indicate the negative electrode 9. First, the case where the notch forming step S3 is performed after the rolling step S2 (FIG. 2A) will be described. In addition, the numerical values of the materials, dimensions, and the like of the components shown below are examples, and the present embodiment is not limited to these.

The current collector 80 of the positive electrode 8 uses an Al foil (for example, a thickness of 15 μm). And Li as a positive electrode active material
A paste is prepared by mixing Mn ₂ O ₄ , graphite as a conductive agent, polyvinylidene fluoride (PVDF) as a binder, and N-methyl-2-pyrrolidone (NMP) as a solvent. In the active material application step S1, FIG.
As shown in (a), the above-mentioned paste is, for example, 75 μm on one side.
10 m at the center of the current collector 80 (the hatched portion in FIG. 3A), that is, on both sides of the attachment region 8a.
The above non-adhesion region 8b (the non-hatched portion in FIG. 3A) is provided, and is applied using an application member (comma coater) P1 (see FIG. 3A).
and b. Next, drying at 150 ° C. is performed. At this time, the density of the electrode (the density of the active material) is 1.6 g / cm ^3.
It is.

Thereafter, in the rolling step S2, the purpose is to improve the contact between the particles, the contact with the current collector 80 to increase the conductivity and the electrode strength, and to use the volume inside the battery effectively.
A rolling press is performed by a roll press P2 (FIG. 3)
(See (b)) Increase the electrode density. Specifically, by adjusting the electrode density from about 2.5 g / cm ³ to about 3.1 g / cm ³ , a battery having excellent battery capacity, cycle characteristics, and output characteristics can be obtained.

As shown in FIG. 3 (c), the notch forming step S3 is performed by cutting or punching with a metal cutter to form the edge 81 of the current collector 80 (the non-adhered area 8b).
A plurality of slits 11 and holes 12 as notches
To form Then, in the electrode shape correction step S4, the positive electrode 8 is deformed at the slit 11 and the hole 12 so as to reduce the arc-shaped warp x (see FIG. 4A) described in the section of the subject. Perform shape correction.

Similarly to the positive electrode 8, the negative electrode 9 is manufactured by performing an active material coating step S1, a rolling step S2, a notch forming step S3, and an electrode shape correcting step S4. The current collector 90 of the negative electrode 9 is C
U foil (for example, 10 μm in thickness) is used. Then, a paste was prepared by mixing MCMB (mesophase carbon microbeads), PVDF, and NMP as the negative electrode active material, and this paste was applied to a thickness of 45 μm on one side, and 130
The negative electrode 9 having a film thickness on one side of 35 μm and an electrode density of 1.4 g / cm ³ was prepared by drying at a temperature of ° C and a rolling press. And
Notch formation and shape correction are performed.

In the battery assembling step S5, the positive electrode 8 and the negative electrode 9 that have been subjected to the shape correction are connected to the shaft core 2 (for example, 25 μm in thickness) through a PP microporous separator 10 (for example, 25 μm in thickness) made by Tonen Tapils. (Diameter 8 mm). Here, for example, the positive electrode width can be 177 mm, the length is 3000 mm, the negative electrode width is 181 mm, and the length is 3160 mm. Then, the battery is assembled in the container 1, and the edges 81, 91 of the current collectors 80, 90 and the end plates 13, 14 are welded, injected with an electrolytic solution, sealed, and the like, thereby completing the battery of the present embodiment. .

On the other hand, when the notch forming step S3 is performed before the rolling step S2 (FIG. 2 (b)), the adhesion region 8
Since the slits 11 and the holes 12 absorb the distortion caused by the difference in the elongation of the material between the a and the non-adhesion region 8b, the arc-shaped warp x can be reduced during rolling. Thereafter, a battery assembling step S5 is performed to complete the battery of the present embodiment.

Therefore, the notch forming step S3 is replaced with the rolling step S
Regardless of whether it is performed before or after 2, the arc-shaped warp x of each of the electrodes 8, 9 can be similarly reduced. The effect of the slit 11 or the hole 12 will be described below. Here, FIG.
4A is a schematic view showing an arc-shaped warp x, and FIG. 4B is a schematic diagram showing a winding displacement y of the positive electrode 8 and the negative electrode 9 after the battery assembling step S5, that is, after winding. The unit of the arc-shaped warp x and the unit of the winding deviation y are mm / m and m, respectively.
m.

Edges 81, 91 of current collectors 80, 90, which are leads for joining with end face plates 13, 14, respectively.
When only the slit 11 is provided, the arc-shaped sled x is
The conventional 10 mm / m was reduced to 0.2 mm / m. In the battery in which the current collectors 80 and 90 were wound to form the positive electrode 8 and the negative electrode 9, the winding deviation y could be suppressed to 0.3 mm compared to the conventional 20 mm.

When only the holes 12 are provided at the edges 81 and 91 of the current collectors 80 and 90, the warp x on the arc is 0.8 mm.
/ M, and the winding deviation y was reduced to 0.4 mm. When both the slits 11 and the holes 12 are provided in the edges 81 and 91 of the current collectors 80 and 90, the arc-shaped sled x is 0 mm /
m, and the winding deviation y could be suppressed to 0.2 mm. Further, if the slit 11 alone is used, the electrodes 8 and 9 are likely to be cut in the slit direction, that is, the end point of the slit 11 is extended. However, such a problem can be prevented by the hole 12.

After the electrode is wound and welded at the end face, the electrolyte is injected. In this injection, conventionally, only the electrolyte flow path from the upper surface of the electrode end face is secured. It is just being done. However, in the present embodiment, by providing the hole 2a for injecting the electrolyte in the shaft core 2, the slit 11 and the hole 12 also secure the electrolyte flow path from the inside, and the injection time of the electrolyte can be shortened. . This is shown in FIG. FIG. 5 is an explanatory diagram showing a flow when the electrolyte solution flow path formed by the holes 12 is injected.

At the time of the injection of the electrolyte, the electrolyte injected from above the shaft core 2 passes through each of the slits 11 and the holes 12 through the hole 2a.
And flows between the positive electrode 8 and the negative electrode 9. Specifically, in the battery provided with the holes 12, the time for injecting a prescribed amount of the electrolyte can be reduced to 20 minutes compared to 40 minutes in the conventional battery. (Other Embodiments) The notch is the slit 1
It is not limited to 1 and the holes 12, and the shape is not limited. For example, a U-shaped or V-shaped notch may be used.

Further, in the above embodiment, the notches (11, 12) are formed at the current collectors 80, 90 of the poles 8, 9 by the edge portions 81, on the side of the end face plates 13, 14 to be welded. Although it is provided at 91, it may be provided at the opposite edges of the edges 81 and 91 of the current collectors 80 and 90. In this case, a non-adhesion area may be provided on the opposite edge.

When the notch forming step S3 is performed after the rolling step S2, the electrode shape correcting step S4 may be omitted. In this case, the electrodes (8, 9) are notched (11, 12) so as to reduce the winding deviation y during the winding in the battery assembling step S5 during the winding in the battery assembling step S5. What is necessary is just to wind while deforming. When the notch forming step S3 is performed before the rolling step S2, an electrode shape correcting step S4 may be further performed between the rolling step S2 and the battery assembling step S5.

In taking out electrons from the non-adhesion region, other than welding the end face plates 13 and 14 and the non-adhesion regions 8b and 9b as described above, the non-adhesion region 8
A current collecting ribbon (e.g., one made of Al for the positive electrode and one made of Cu for the negative electrode) is joined to each of the electrodes b and 9b by welding or the like so that the holes are not closed. It is good also as a structure which conducts to the child 3,4.

The extraction of the electrons is performed by welding the end face plates 13 and 14 with the non-adhesion regions 8b and 9b as described above, and the current collector ribbon is connected to the non-adhesion regions 8b and 9b of the current collectors 80 and 90. (The edge portions 81 and 91) may be used as a reinforcing member. In addition, the width of the edges 81 and 91 is the same as that of the non-adhesion region 8.
The edges 81, 91, which are larger than the widths of b, 9b, may also include the attachment areas 8a, 9a. In this case, the slits 11 and the holes 12 provided in the edges 81 and 91 are provided.
Extend to the attachment regions 8a, 9a and extend to both regions 8a, 8a.
It may be formed so as to straddle b, 9a, 9b.

The above embodiment is not limited to a lithium ion secondary battery, but can be applied to any wound battery.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram showing a configuration of a wound battery according to an embodiment of the present invention.

FIG. 2 is a process chart showing a method for manufacturing a battery according to the embodiment.

FIG. 3 is an explanatory diagram for explaining the manufacturing method of FIG. 2;

FIG. 4A is a schematic diagram showing an arc-shaped warpage of an electrode, and FIG. 4B is a schematic diagram showing a winding deviation of a battery.

FIG. 5 is an explanatory diagram showing a flow of an electrolyte at the time of injection in the embodiment.

FIG. 6 is an explanatory view showing a method for manufacturing a conventional wound battery.

[Explanation of symbols]

8 Positive electrode, 9 Negative electrode, 8a, 9a Adhered area, 8b, 9
b: non-adhesion area, 11: slit, 12: void, 80,
90 ... current collector, 81, 91 ... edge, 82, 92 ... outer peripheral end of current collector.

Claims (5)

[Claims] 1. A conductive foil having an attached area (8a, 9a) on the same surface to which an electrode active material is attached and a non-adhered area (8b, 9b) to which no electrode active material is attached is rolled. Electrodes (8, 9) formed by winding current collectors (80, 90) formed in such a manner that the non-adhesion regions (8b, 9b) are formed in the current collectors (80, 9).
0) of the edges (81, 91) extending along the winding direction
In the battery provided in (1), notches (11, 12) for absorbing distortion are formed in the edges (81, 91). 2. The notch is formed by the edge (81, 91).
In the outer peripheral end portions (82, 82) of the current collectors (80, 90),
92) and holes (81, 91) formed inside the outer peripheral ends (82, 92) of the current collectors (80, 90) at the edges (81, 91). The battery according to claim 1, comprising at least one of (12). 3. The slit (1) is formed by the hole (12).
3. The battery according to claim 2, wherein the battery is formed at the end point of the cut of 1). 4. The battery according to claim 2, wherein the slit (11) has a cut length shorter than a width of the non-adhesion region (8b, 9b). 5. A conductive foil having an adhesion area (8a, 9a) to which the electrode active material is adhered on the same surface and a non-adhesion area (8b, 9b) to which the electrode active material is not adhered is rolled. Electrodes (8, 9) formed by winding current collectors (80, 90) formed in such a manner that the non-adhesion regions (8b, 9b) are formed in the current collectors (80, 9).
0) of the edges (81, 91) extending along the winding direction
The electrode active material is attached to the foil, and the attachment area (8) is provided.
a, 9a) and forming the current collector (80, 90) having the non-attached areas (8b, 9b); and the current collector having both areas (8a, 9a, 8b, 9b). Forming notches (11, 12) at the edges (81, 91) of (80, 90) for absorbing strain; and forming the notches having both regions (8a, 9a, 8b, 9b). A method for producing a battery, comprising: a step of rolling a current collector (80, 90); and a step of winding the current collector (80, 90).