JP2000003722A - Battery and its manufacture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To further increase the battery capacity by making surplus spaces inside a battery can minimum. SOLUTION: A diameter D of a winding core part 40 of a winding group formed by winding a band positive electrode plate 20 and a band negative electrode plate 22 through an outside separator 24 and an inside separator 26 is set at 2 mm or less. In this case, a positive electrode lead 52 is led out of a position, corresponding to a position outside at 2 mm of radius or more from the center of a winding group 16, and a negative electrode collector provided outermost of the winding group and the inner wall surface of the battery can 12 are made to electrically contact with each other through a conductive elastic member 62.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a battery having an electrode group formed by winding a strip-shaped positive electrode plate and a strip-shaped negative electrode plate with a separator interposed therebetween, and a method of manufacturing the same.

[0002]

2. Description of the Related Art In recent years, in a cylindrical battery, in order to increase the battery capacity, in addition to the improvement of a positive electrode plate and a negative electrode plate, reduction of excess space in a battery can has been performed. .

As a method of reducing the excess space in the battery can, for example, a method has been proposed in which a groove of a beading portion (annular groove portion) is crushed after caulking (see, for example, Japanese Patent Application Laid-Open No. 9-50792).

In this method, an annular groove is formed in the vicinity of an opening of a battery can into which a winding group is put, and then an electrolyte is injected into the battery can. Thereafter, the gasket and the sealing member are incorporated, the end of the opening side of the battery can is bent inward to perform caulking, and the annular groove is crushed by compressing the caulked portion in the axial direction. .

According to this method, the internal volume of the battery can is effectively increased, and the height of the winding group and the amount of the electrolyte can be increased.

As a method of reducing the excess space in the battery can, in addition to the above-described method, for example, a method of physically winding a winding group at a high density (for example, Japanese Patent Laid-Open No. 10-1226).
No. 5) and a method of directly contacting the negative electrode plate with the inner wall of the battery can (see, for example, Japanese Patent No. 2695684).

[0007]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a battery and a method of manufacturing the same, which can minimize the extra space in the battery can and can further increase the battery capacity. With the goal.

[0008]

The battery according to the present invention has a winding group formed by winding a strip-shaped positive electrode plate and a strip-shaped negative electrode plate with a separator interposed therebetween so that the diameter of the core is 2 mm or less. Constitute.

As a result, not only the extra space on the inner wall surface of the battery can but also the extra space formed by the core of the winding group can be reduced, and the battery capacity can be further increased. .

In the above structure, it is preferable that the positive electrode lead is taken out from a position corresponding to a radius of 2 mm or more from the center of the winding group toward the outer periphery. The core diameter is 2
mm or less, if a conventional configuration in which the positive electrode lead is disposed on the winding core portion is adopted, the positive electrode lead is not well curved and its roundness is reduced, or the positive electrode lead is deformed and assembled. This is because there is a possibility of affecting the bending and welding of the positive electrode lead in the process.

In the above structure, an uncoated area of the active material may be provided at a position corresponding to a radius of at least 2 mm from the center of the winding group and closer to the outer periphery, and the positive electrode lead may be fixed to the uncoated area. . In this case, the positive electrode lead can be securely fixed to the positive electrode plate.

In the above structure, it is preferable that the outermost negative electrode current collector in the winding group is brought into contact with the inner wall of the can. This is because the diameter of the core part is 2 mm or less, so that it becomes impossible to insert a welding rod for resistance welding into the core part, thereby making it impossible to weld the negative electrode lead to the bottom of the can. It is. Therefore, it is possible to conduct electricity by eliminating the negative electrode lead and bringing the outermost negative electrode current collector in the winding group into contact with the inner wall of the can.

In this case, it is desirable that the outermost negative electrode current collector in the winding group and the inner wall of the can be electrically contacted via a conductive elastic member. In general, the contact between the outermost negative electrode current collector and the inner wall of the can in the winding group is ensured by the expansion of the winding group in a charged state. It is conceivable to make the outer diameter of the group approximately equal to the inner diameter of the can. However, when the outer diameter of the winding group is made smaller than the inner diameter of the can, or when the outer diameter of the winding group becomes smaller than the inner diameter of the can due to manufacturing variations, conduction is not achieved by the above-described method. May be sufficient.

As described above, when the outermost negative electrode current collector in the winding group is brought into contact with the inner wall of the can, the contact state is determined by the outer diameter of the winding group and the inner diameter of the can. By electrically contacting the outermost negative electrode current collector in the winding group and the inner wall of the can via a conductive elastic member, the outer diameter of the winding group is smaller than the inner diameter of the can. Even if it ’s small,
Conduction can be reliably achieved.

[0015] In the above structure, in order to ensure the contact between the inner wall of the can and the negative electrode current collector,
The hollow may be provided in the can, or another beading groove (annular groove) may be provided.

Further, in the above configuration, an uncoated area of the active material may be provided on the outermost periphery of the negative electrode current collector, and the elastic member may be fixed to the uncoated area. In this case, the elastic member can be securely fixed to the negative electrode current collector.

Further, in the above structure, an uncoated area of the active material may be provided from an end portion of the inner peripheral side of the negative electrode current collector to a portion corresponding to a fixed portion of the elastic member. The uncoated region is a portion that does not contribute to the battery reaction, and by not forming an active substance in the portion,
As a result, the volume of the active substance is reduced, and the portion contributing to the battery reaction can be packed more in the can.

As described above, even when the elastic member is provided, the can may be provided with a recess in order to ensure the contact between the inner wall of the can and the elastic member. May be provided.

Next, in the method for producing a battery according to the present invention, when the negative electrode sheet, the positive electrode sheet and the separator are wound to form a winding group, the negative electrode sheet is formed so that the diameter of the core becomes 2 mm or less. The sheet, the positive electrode sheet and the separator are wound.

As a result, not only the extra space on the inner wall surface of the battery can but also the extra space formed by the core of the winding group can be reduced, and the battery capacity can be further increased. .

In this case, of the positive electrode sheet, a positive electrode lead is stuck to a position corresponding to a radius of 2 mm or more from the center of the wound group when the group is formed into the wound group, and the outer periphery of the positive electrode sheet is formed. And a separator may be wound.

In the positive electrode sheet, an uncoated region of the active material is formed at a position corresponding to a radius of at least 2 mm from the center of the winding group when the winding group is formed, and the positive electrode sheet is formed in the uncoated region. The negative electrode sheet, the positive electrode sheet, and the separator may be wound by attaching a lead.

When the winding group is inserted into the can without attaching the negative electrode lead to the negative electrode sheet, the outermost negative electrode current collector of the winding group positively contacts the inner wall of the can. You may make it do.

In order to ensure the contact between the inner wall of the can and the negative electrode current collector, a recess may be formed in the can, or another beading groove may be formed.

In the above method, in the case where the wound group is formed in the negative electrode sheet, a conductive elastic member is attached to a portion corresponding to the outermost periphery thereof,
A positive electrode sheet and a separator are wound to form the winding group,
It is preferable that, when the winding group is inserted into the can, the negative electrode current collector at the outermost periphery of the winding group and the inner wall of the can be brought into contact with each other via the conductive elastic member.

In this case, when the wound group is formed in the negative electrode sheet, an uncoated area of the active material is formed in a portion corresponding to the outermost periphery thereof, and the elastic member is attached to the uncoated area. Then, the negative electrode sheet, the positive electrode sheet, and the separator may be wound.

In the inner peripheral side of the negative electrode sheet, an uncoated region of the active material may be formed from an end to a portion corresponding to a fixed portion of the elastic member.

In order to secure the contact between the inner wall of the can and the elastic member, a recess may be formed in the can or another beading groove may be formed.

[0029]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment in which a battery according to the present invention and a method of manufacturing the same are applied to, for example, a cylindrical battery (hereinafter simply referred to as a battery according to the embodiment) will be described with reference to FIGS. This will be described with reference to FIG.

As shown in FIG. 1, a battery 10 according to the present embodiment is sealed together with a battery can 12 having a cylindrical shape with a bottom and a non-aqueous electrolyte 14 containing a lithium salt in the battery can 12. A winding group 16 and a sealing body 18 are provided. The sealing body 18 is connected to the opening 12 of the battery can 12 through a gasket 30.
It is fixed to the end on the a side.

As shown in FIG. 2, the winding group 16 includes a strip-shaped positive electrode plate 20 having a layer mainly composed of a lithium-containing metal oxide, a mixture layer mainly composed of a negative electrode material, and a top surface of the mixture layer. A belt-like negative electrode plate 22 in which a metal material mainly composed of lithium is overlapped is wound around a belt-like outer separator 24 and an inner separator 26.

An annular groove 32 is formed in the battery can 12 near the opening 12a. In the battery can 12, a lower insulating plate 34 and an upper insulating plate 36 are provided for the winding group 16.

The battery 10 according to this embodiment
As shown in FIG. 2, the diameter D of the core part (space) 40 in the winding group 16 is 2 mm or less. When making this winding group 16, the winding group 16 is manufactured by winding the positive electrode plate 20, the negative electrode plate 22, and the separators 24 and 26 using a winding shaft having a diameter of 2 mm or less, or a plurality of winding groups. What is necessary is just to produce the said winding group 16 by surface winding with a touch roller. The outer separator 24 is provided with a wrapping tape 4 so that the winding state of the winding group 16 does not easily come off.
2 is stuck.

As shown in FIGS. 3A to 3D, the length relationship between the positive electrode plate 20, the negative electrode plate 22, the outer separator 24, and the inner separator 26 constituting the winding group 16 is as follows. Next to the separator 24 is the negative electrode plate 22, and the positive electrode plate 20 is set to be the shortest.

The positive electrode plate 20, the negative electrode plate 22,
When the outer separator 24 and the inner separator 26 are wound, each end of the outer separator 24 and the inner separator 26 is located at a winding start position (corresponding to the inner peripheral end of the winding group 16) P1. One end of the negative electrode plate 22 is located at a position P2 in the middle of winding advanced by La from the start position P1,
One end of the positive electrode plate 20 is located at a position P3 in the middle of winding, which is advanced by Lb (> La) from the start position P1.

The other end of the inner separator 26 is located at the winding end position (corresponding to the outer peripheral end of the winding group) P4.
The other end of the negative electrode plate 22 is located at a position P5 in the middle of winding, which is returned to the inner peripheral side by Lc from the terminal position P4, and a position P in the middle of winding, which is returned by Ld (> Lc) from the terminal position P4.
6, the other end of the outer separator 24 and the other end of the positive electrode plate 20 are located substantially in the same manner.

Therefore, the portion of the negative electrode plate 22 that does not face the positive electrode plate 20 (the other end of the negative electrode plate 22 is
0) and the portion facing the inner wall surface of the can is a portion that does not contribute to the battery reaction.

In the case where the positive electrode plate 20 is the winding group 16, the radius of the winding group 16 is at least 2 mm from the center of the winding group 16 and is closer to the outer periphery. An area 50 (see FIG. 3C) is provided, and the positive electrode lead 52 is fixed to the uncoated area 50. This fixation can be performed by ultrasonic welding or caulking. In this case, it is desirable to attach a resin tape 54 to the uncoated area 50 in order to protect the positive electrode lead 52. The positive electrode lead 52 extends toward the opening 12a of the battery can 12 through the opening 56 provided in the upper insulating plate 36, as shown in FIG.
To be welded.

When the positive electrode plate 20 is formed into a winding group 16, there is a portion which does not face the negative electrode plate 22 over a predetermined range from the inner end on the inner peripheral side, and this portion also has no active material. An application area 58 (see FIG. 3C) is provided.

On the other hand, as shown in FIG. 3D, the negative electrode plate 22 has an uncoated area 60 of the active material in a portion not contributing to the battery reaction outside the other end (a portion facing the inner wall surface of the battery can 12). A conductive elastic member 62 such as a copper foil is fixed to the uncoated region 60. For this fixation, ultrasonic welding or the like can be used. Further, the negative electrode plate 2
In No. 2, an uncoated region 64 of the active substance is provided in a portion not contributing to the battery reaction (a portion not facing the positive electrode plate 20) inside the other end.

Then, as shown in FIGS. 2 and 4, by putting the winding group 16 into the battery can 12, the elastic member 62 fixed to the negative electrode plate 22 is directly attached to the inner wall surface of the battery can 12. Will come into contact. That is, the elastic member 62
Will function as a negative electrode lead.

When assembling the battery 10 according to this embodiment, the lower insulating plate 34 is placed on the bottom of the battery can 12 and then the upper insulating plate 36 is placed on the upper end surface of the winding group 16. Then, the winding group 16 is inserted into the battery can 12.

Thereafter, usually, the negative electrode lead and the bottom of the can are welded to establish conduction between the negative electrode current collector and the battery can 12, but in the present embodiment, the negative electrode current collector and the battery Since the inner wall surface of the can 12 is brought into electrical contact with the conductive elastic member 62, conduction between the negative electrode current collector and the battery can 12 is achieved only by inserting the winding group 16 into the battery can 12. Therefore, the omission of the welding step can be realized.

When the insertion of the winding group 16 into the battery can 12 is completed, the annular groove 3 is formed near the opening 12 a of the battery can 12.
2 is formed, and the electrolyte 14 is injected into the battery can 12. Then, after welding the positive electrode lead 52 and the sealing body 18, the positive electrode lead 52 is folded and the sealing body 18 is attached, and then the end of the battery can 12 on the side of the opening 12 a is bent inward and caulked. By doing so, the battery 10 according to the present embodiment is completed.

As described above, the battery 10 according to the present embodiment
Since the diameter D of the core part 40 in the winding group 16 is set to 2 mm or less, not only the extra space on the inner wall surface of the battery can 12 but also the extra space formed by the core part 40 of the winding group 16. And the battery capacity can be further increased.

By the way, since the diameter D of the core portion 40 is 2 mm or less, if a conventional configuration in which the positive electrode lead 52 is disposed on the core portion 40 is adopted, the positive electrode lead 52 will not be well curved. The roundness is reduced, or the positive electrode lead 52 is deformed, and the positive electrode lead 52 in the assembling process is reduced.
Bending and welding may be affected.

However, in the present embodiment, since the positive electrode lead 52 is taken out from the center of the winding group 16 at a position corresponding to a radius of 2 mm or more and closer to the outer periphery, the above-described inconvenience does not occur. Moreover, the winding group 1
An active substance non-application area 50 is provided at a position corresponding to a radius of 2 mm or more from the center of the active substance to an outer periphery thereof.
Since the positive electrode lead 52 is fixed to the positive electrode plate 0, the positive electrode lead 52 can be securely fixed to the positive electrode plate 20.

If the diameter D of the core portion 40 is 2 mm or less, it becomes impossible to insert a welding rod for resistance welding into the core portion 40, thereby making it impossible to weld the negative electrode lead to the can bottom. May be possible.

However, in this embodiment, the negative electrode lead is eliminated, and the outermost negative electrode current collector in the winding group 16 and the inner wall surface of the battery can 12 are electrically connected via the conductive elastic member 62. Since the contact is made, conduction between the negative electrode current collector and the battery can 12 can be achieved, and it becomes unnecessary to weld the negative electrode lead to the bottom of the can.

Incidentally, the contact between the negative electrode current collector on the outermost periphery in the winding group 16 and the inner wall of the battery can 12 is usually ensured by the expansion of the winding group 16 in a charged state, but is ensured before charging. When making contact, it is conceivable to make the outer diameter of the winding group 16 substantially equal to the inner diameter of the battery can 12. However, when the outer diameter of the winding group 16 is smaller than the inner diameter of the battery can 12, or when the outer diameter of the winding group 16 is smaller than the inner diameter of the battery With the method described above, there is a possibility that conduction may be insufficient.

That is, when the outermost negative electrode current collector in the winding group 16 is brought into contact with the inner wall of the battery can 12, the contact state is determined by the outer diameter of the winding group 16 and the inner diameter of the battery can 12. That is, as in the present embodiment, the outermost negative electrode current collector in the winding group 16 and the inner wall surface of the battery can 12 are electrically contacted via the conductive elastic member 62. Even if the outer diameter of the winding group 16 is smaller than the inner diameter of the battery can 12, conduction can be reliably achieved.

In order to ensure conduction between the negative electrode current collector and the inner wall surface of the battery can 12, a recess may be provided in the battery can 12, or another beading groove (annular groove) may be formed. It may be provided. In this case, the elastic member 6
The depression or beading groove may be formed at a portion where the second member 2 is located, or the depression or beading groove may be formed at a portion where the elastic member 62 is not located.

In the present embodiment, the non-coated region 60 of the active material is provided on the outermost periphery of the negative electrode current collector, and the elastic member 62 is fixed to the non-coated region 60. The elastic member 62 can be securely fixed to the elastic member 62.

Further, in the present embodiment, the uncoated region 64 of the active material is provided from the other end of the negative electrode plate 22 to the portion corresponding to the fixed portion of the elastic member 62 on the inner peripheral side of the negative electrode current collector. Like that. These uncoated regions 60 and 64 are portions that do not contribute to the battery reaction. Since no active material is formed in these portions, the volume of the active material is reduced accordingly, and the portion that contributes to the battery reaction is reduced to the battery can 12. It is possible to pack more inside.

The battery and the method of manufacturing the same according to the present invention are not limited to the above-described embodiment, but may adopt various configurations without departing from the gist of the present invention.

[0056]

As described above, according to the battery and the method of manufacturing the same according to the present invention, the excess space in the battery can can be minimized, and the battery capacity can be further increased. Can be.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing a schematic configuration of a battery according to an embodiment.

FIG. 2 is a cross-sectional view illustrating a schematic configuration of a battery according to the present embodiment.

FIG. 3A is an explanatory view showing an inner separator;
FIG. 3B is an explanatory diagram showing an outer separator, FIG. 3C is an explanatory diagram showing a positive electrode plate, and FIG. 3D is an explanatory diagram showing a negative electrode plate.

FIG. 4 is a perspective view showing a winding group of the battery according to the present embodiment.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 10 ... Battery 12 ... Battery can 16 ... Winding group 20 ... Positive electrode plate 22 ... Negative electrode plate 24 ... Outer separator 26 ... Inner separator 40 ... Core part (space) 50, 58, 60, 64 ... Uncoated area 52 ... Positive electrode Lead 62: Elastic member

 ──────────────────────────────────────────────────続 き Continued on the front page F-term (reference) CC24 HH05

Claims (15)

[Claims] 1. A battery having a winding group formed by winding a strip-shaped positive plate and a strip-shaped negative plate with a separator interposed therebetween, wherein the core has a diameter of 2 mm or less. 2. The battery according to claim 1, wherein a positive electrode lead is taken out from a position corresponding to a radius of 2 mm or more from the center of the winding group toward the outer periphery. 3. The battery according to claim 1, further comprising a non-coated area of the active material at a position corresponding to a radius of at least 2 mm from the center of the winding group and closer to the outer circumference, and a positive electrode lead is fixed to the uncoated area. A battery comprising: 4. The battery according to claim 1, wherein the outermost negative electrode current collector in the winding group is in contact with the inner wall of the can. 5. The battery according to claim 4, wherein the can has a depression at a contact portion between an inner wall of the can and the negative electrode current collector to ensure the contact. 6. The battery according to claim 4, wherein the can has a beading groove at a contact portion between the inner wall of the can and the negative electrode current collector to ensure the contact. battery. 7. The battery according to claim 1, wherein the outermost negative electrode current collector in the winding group and the inner wall of the can are electrically contacted via a conductive elastic member. battery. 8. The battery according to claim 7, further comprising an uncoated area of the active material on the outermost periphery of the negative electrode current collector, wherein the elastic member is fixed to the uncoated area. battery. 9. The battery according to claim 8, wherein an active material-uncoated area is provided from an end portion to a portion corresponding to a fixed portion of the elastic member on an inner peripheral side of the negative electrode current collector. And batteries. 10. The battery according to claim 7, wherein the can has a recess at a contact portion between an inner wall of the can and the elastic member to ensure the contact. Battery. 11. The battery according to any one of claims 7 to 9, wherein the can has a beading groove at a contact portion between an inner wall of the can and the elastic member to ensure the contact. A battery comprising: 12. A winding core having a diameter of 2 m when winding a negative electrode sheet, a positive electrode sheet and a separator to form a winding group.
m, wherein the negative electrode sheet, the positive electrode sheet and the separator are wound so as to be not more than m. 13. The method for manufacturing a battery according to claim 12, wherein the positive electrode lead is placed at a position corresponding to a radius of 2 mm or more from the center of the wound group in the positive electrode sheet. A method for producing a battery, comprising attaching and winding the negative electrode sheet, the positive electrode sheet, and the separator. 14. The method for producing a battery according to claim 12, wherein the active material is located at a position corresponding to a radius of 2 mm or more from the center of the wound group in the positive electrode sheet. A method for producing a battery, comprising: forming an uncoated region; attaching a positive electrode lead to the uncoated region; and winding the negative electrode sheet, the positive electrode sheet, and a separator. 15. The method for manufacturing a battery according to claim 12, wherein when the winding group is inserted into a can without attaching a negative electrode lead to the negative electrode sheet, a positive end of the winding group is positively applied. A method for producing a battery, comprising contacting an outer peripheral negative electrode current collector with an inner wall of a can.