JP2001118562A - Method of forming lead - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily and surely form a plurality of leads in a radial manner that are led out in circumference and in a row. SOLUTION: In a lead-forming process for bending a plurality of leaf like leads 11a, 12a led out in the axial direction of a cylindrical accumulated layer electrode body, for example a battery main body 2 in the radial direction, it is formed by inserting a forming shaft of which leading edge is conical into a center hole 2h of the cylindrical accumulated layer electrode body and inclining the leaf-like leads 11a, 12a in the radial direction that its section is a circular from the axial direction of a battery body.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lead forming method for shaping leads in a non-aqueous electrolyte secondary battery or the like.

[0002]

2. Description of the Related Art In recent years, for example, in the fields of automobiles, home electric appliances, computers, etc., non-aqueous electrolyte secondary batteries, for example, lithium secondary batteries have high battery voltage and high energy density. As a power source for the battery, it has been increasingly used. Under such circumstances, it is necessary to improve the mass productivity of this battery manufacturing, and it is important that a high yield can be obtained. It is coming.

A nonaqueous electrolyte secondary battery 200 has a cylindrical outer can 20 as shown in FIG.
1, a battery main body 202 is accommodated, and a non-aqueous electrolyte is injected into an outer can 201. The battery main body 202 is impregnated with the non-aqueous electrolyte.

[0004] A battery body 202 has a laminated electrode body in which a film-shaped positive electrode 101 and a film-shaped negative electrode 102 are similarly laminated via a film-shaped separator 103, around a cylindrical, for example, cylindrical shaft 106. It has a configuration wound around.

[0005] At both ends of the cylindrical battery body 202, for example, a disk-shaped positive electrode current collector 204 and a negative electrode current collector 205 are formed.
The battery body 202 is accommodated in an outer can 201 formed of a bottomed cylindrical body such that the negative electrode current collector is located on the bottom side of the outer can 201, and the open end of the outer can 201 is secured. It is closed by a top cover 206 having a mechanism (not shown).

In a non-aqueous electrolyte secondary battery such as described above, for example, a lithium secondary battery, it is necessary to form the positive electrode lead 101a and the negative electrode lead 102a radially. Needed.

[0007] A conventional method for forming a foil-like lead constituting, for example, a lithium secondary battery will be described below with reference to the drawings. FIG. 11 shows a schematic plan view of a positive electrode 101 and a negative electrode 102 constituting a lithium secondary battery. As shown in FIG. 11, a positive electrode 101 and a negative electrode 102 are formed of an electrode foil 101b having a long shape.
And 102b, a positive electrode active material layer 101c and a negative electrode active material layer 102c are respectively applied.

The positive electrode 101 and the negative electrode 10
2 is formed at one side edge of each of the electrode foils 101b and 102b while maintaining a required interval, and a plurality of strip-shaped positive electrode leads 101a and negative electrode leads 102a are arranged between adjacent cuts 101d and 102d. Have been.

The positive electrode 101 and the negative electrode 102 shown in FIG. 11 are laminated with a separator 103 interposed therebetween to form a laminated electrode body 105 as shown in FIG. The laminated electrode body 105 has a cylindrical shape such as a cylindrical shaft 1.
06, a spirally wound structure is formed to form the cylindrical laminated electrode body 107 as shown in FIG. 13, that is, the battery body 202 shown in FIG.

A plurality of foil-like positive electrode leads 101a and negative electrode leads 102a protrude from the positive electrode 101 and the negative electrode 102 from both ends of the cylindrical laminated electrode body 107, that is, from both ends of the battery main body 202, respectively. I have. FIG. 13 shows only the lead-out side of the positive electrode lead 101a of the cylindrical laminated electrode body 107.

The foil-like leads 101a and 102a provided at both ends of the cylindrical laminated electrode body 107 radially bend their free ends outward. FIG. 14 shows a state in which a part thereof is bent. As described above, for example, in a non-aqueous electrolyte secondary battery, it is necessary to form the lead by bending the electrode lead to the outside, but this has conventionally been performed manually.

[0012]

However, as described above, when the leads 101a and 102a, which have been established at both ends of the cylindrical laminated electrode body 107, are radially manually bent and formed, these leads 101a are formed.
And 102a are extremely difficult to form accurately and radially.

That is, the leads 101a and 102b
At the end of each cylindrical laminated electrode body 107,
Normally, since about 200 trees are formed, it is technically extremely difficult to form them strictly one by one so that they all open radially. That is, a plurality of leads 101a and 102a are bundled and bent in the same direction, or the leads are twisted, and it is difficult to form the leads in an accurate radial shape. In particular, the leads are twisted or broken at the roots of the leads. This causes a short circuit after the battery is manufactured.

The inventor of the present invention has conducted intensive studies and has found that the forming of the positive electrode lead 101a and the negative electrode lead 102a can be performed easily and accurately in the radial direction from the axial direction of the cylindrical electrode assembly 107. The present invention provides a simple lead forming method.

[0015]

According to the lead forming method of the present invention, in a lead forming step of radially bending a plurality of foil-like leads led out from a cylindrical laminated electrode body substantially in the axial direction thereof, the lead forming step comprises the steps of: A forming shaft having a conical tip is inserted into the central hole of the laminated electrode body, and the foil lead is formed by tilting the foil lead in the radial direction from the axial direction of the cylindrical laminated electrode body.

According to the lead forming method of the present invention, in forming a lead in a manufacturing process of a non-aqueous electrolyte secondary battery, a large number of foil-shaped leads formed from both ends of a cylindrical laminated electrode body are pushed down by a forming shaft, By forming this radially, it is possible to shorten the forming time, to ensure the work, and to automate the work.

[0017]

DETAILED DESCRIPTION OF THE INVENTION A lead forming method according to the present invention is directed to a method of forming a plurality of foil-like leads, which are led out from a cylindrical laminated electrode body, for example, a battery body of a non-aqueous electrolyte secondary battery, substantially in the axial direction thereof. In the lead forming step of bending in the radial direction, the tip is inserted into the central hole of the cylindrical laminated electrode body, the conical forming shaft is inserted, and the standing foil-shaped lead is inserted from the axial direction of the cylindrical laminated electrode body. Forming is performed by tilting the section in the radial direction of the circle.

A case where the lead forming method of the present invention is applied to a non-aqueous electrolyte secondary battery will be described below with reference to the drawings. Note that the method of the present invention is not limited to the examples shown below. That is, a conventionally known battery,
Alternatively, the present invention can be applied to any device having a lead forming step of radially bending a lead of a plurality of leads, such as a condenser, in which a plurality of leads are led out in a cylindrical shape.

First, a non-aqueous electrolyte secondary battery will be described as a specific example to which the method of the present invention is applied. As shown in a schematic cross-sectional view of one example of this nonaqueous electrolyte secondary battery 10, for example, a battery body 2 is housed in a cylindrical outer can 1, and the nonaqueous electrolytic The liquid is injected, and the non-aqueous electrolyte is impregnated in the battery body.

FIG. 3 is a schematic perspective view of the battery main body 2. In the battery body 2 shown in FIG. 3, a film-shaped positive electrode 11 and a film-shaped negative electrode 12 as shown in FIG. The body 15 is configured. FIG.
As shown in FIG. 5, the positive electrode 11 and the negative electrode 12 have a long shape, and cuts are formed on each side edge at a required interval, and a strip is formed between these cuts. A plurality of thin foil-shaped positive electrode leads 11a and negative electrode leads 12a are arranged.

The laminated electrode body 15 is wound around, for example, a cylindrical shaft 16 having a center hole to form a cylindrical laminated electrode body, in this example, the battery body 2.

The positive electrode 11 is formed by coating a positive electrode active material 11c on both sides of a long electrode foil 11b made of, for example, an Al foil, and the negative electrode 12 is formed of a long electrode foil made of, for example, a Cu foil. A negative electrode active material 12c is applied to both surfaces of 12b.

The positive electrode active material 11c can be composed of, for example, an active material made of a lithium transition metal oxide.
The negative electrode active material 12c can be made of, for example, an active material made of, for example, carbon that is doped or dedoped with lithium.

A positive electrode lead 11a and a negative electrode lead 12a are arranged between the notches 11d and 12d adjacent to each other at one side edge of each of the electrode foils 11b and 12b of the positive electrode 11 and the negative electrode 12, respectively. Become composed.

The separator 13 is, for example, polyethylene,
A microporous membrane made of polypropylene can be applied.

The positive electrode lead 11a and the negative electrode lead 12
As shown in FIG. 3, a is a cylindrical cylindrical laminated electrode body wound around a shaft 16 in a state of being overlapped with a separator 13 interposed therebetween, that is, the battery body 2, It is made to be located at the end.

As shown in FIG. 1, a positive electrode lead 11a and a negative electrode lead 12a are electrically connected to both ends of the cylindrical battery body 2, for example, a disk-shaped positive current collector 4 and a negative current collector, respectively. The body 5 is placed. The battery body 2
A negative electrode current collector 5 is accommodated in an outer can 1 formed of a bottomed cylindrical body so as to be located on the bottom side of the outer can 1, and an open end of the outer can 1 is provided with a top cover having a safety resistor 40. 6 closed. The safety resistor 40 has a positive temperature characteristic, and prevents a large current from flowing when the positive and negative terminals are short-circuited by mistake.

On the inner surface of the top cover 6, for example, a sub disk 7 made of a conductive material such as a metal and having a swelling portion 7a swelling toward the inside of the outer can 1 is disposed at the center, for example. On the inner surface side, an insulating fixed substrate 8 is arranged, and through a through hole 8h formed in the center of the fixed substrate 8, the bulging portion 7a of the sub disk 7 faces the positive electrode current collector 4 side. Be placed.

The bulging portion 7a of the sub disk 7
Welded to the free end of the lead piece 11t via the safety valve 9,
When the pressure inside the outer can 1 exceeds a required pressure, the sub-disk 7 swells and deforms toward the open end of the outer can 1 due to the internal pressure,
The welded portion between the safety valve 9 and the sub-disk 7 is peeled off and is electrically interrupted. Further, when the internal pressure increases, a break occurs in a part of the top cover 6 where a mechanically weak portion such as a thin portion is formed, so that an abnormal increase in the internal pressure is released.

The non-aqueous electrolyte secondary battery 10 having such a structure
The method of forming the leads 11a and 12a of the present invention in the step of manufacturing the lead will be described below.

In the battery main body 2 shown in FIG. 3, a film-like positive electrode 11 and a film-like negative electrode 12 as shown in FIG. 2 are respectively laminated with a film-like separator 13 interposed therebetween. A laminated electrode body 15 is formed, and the laminated electrode body 15 is wound around a cylindrical shaft 16 having a center hole, for example, to form a cylindrical laminated electrode body as shown in FIG. 4, a battery body in this example. 2 are formed.
In FIG. 4, the illustration of the cylindrical shaft 16 is omitted.

From both ends of the battery body 2, a plurality of thin foil-shaped positive leads 11a and a plurality of negative leads 12a are formed.
“a” protrudes from the positive electrode 11 and the negative electrode 12, respectively, and stands. FIG. 4 shows only the lead-out side of the positive electrode lead 11 a of the battery main body 2.

At both ends of the battery body 2 shown in FIG.
The positive electrode lead 11 which is led out substantially in the axial center direction and has a forest
a and the negative electrode lead 12a need to be bent and formed in the outer circumferential direction of the circle of the cross section of the battery body 2, that is, in the radial direction of the cross section circle, but in the method of the present invention, these lead positive electrode lead 11a and negative electrode lead 12a are formed. In order to accurately and quickly form the 12a radially, a conical forming shaft is inserted into the center hole 2h of the battery body 2 to form a positive electrode lead.
The negative electrode lead is pushed down in the radial direction of the circle of the cross section of the battery body 2 by the forming shaft, and finally all the positive electrode lead 11a and the negative electrode lead 12a are formed. Hereinafter, the lead forming method of the present invention will be described in detail with reference to the drawings.

FIG. 5 is a schematic sectional view showing an example of the battery main body 2 and the forming shaft 30 applied to the method of the present invention. As shown in FIG. 5, the battery body 2 is held by the fixture 21 in a fixed state necessary for performing the lead forming. Next, the positive lead 11a and the negative lead 12a are pressed from the outer periphery by the annular lead pressing ring 22 to prevent scattering to the surroundings.

Next, the forming shaft 30 is inserted into the center hole 2h of the battery body 2. The forming shaft 30 has a distal end portion 30a having a conical shape.
Thus, the positive electrode lead 11a can be inserted into the center hole 2h without buckling inside the center hole 2h of the battery body 2.

As shown in FIG. 5, the forming shaft 30 has a multi-stage pressing mechanism 3 combined in a coaxial circle.
1 to 33 are provided. In this example, it is assumed that a three-stage pressing mechanism is used. That is,
A cylindrical first pressing mechanism 31 having a conical tip portion 30a as a central axis is provided, and the diameter of a center hole 32h of the first pressing mechanism 31 is provided on the outer peripheral portion of the first pressing mechanism 31. A second pressing mechanism 32 having substantially the same size as the diameter of the second pressing mechanism is provided. The second pressing mechanism is movable up and down in FIG. Similarly, a third pressing mechanism 33 is provided on the outer peripheral portion of the second pressing mechanism 32.
Is provided. The center hole 3 of the third pressing mechanism 33
The diameter of 3h is substantially the same as the diameter of the outermost peripheral portion of the second pressing mechanism 32, and is movable up and down in FIG.

The forming shaft 30 as described above
A method for performing lead forming will be described with reference to FIG.

First, the first pressing mechanism 31, which is a central axis and has a conical tip, is protruded and inserted into the central hole 2h of the battery body 2. Thereby, the innermost part of the positive electrode lead 11a is pressed and bent radially.

Next, as shown in FIG. 6, while the first pressing mechanism 31 of the forming shaft 30 is being inserted into the central hole 2h, the second pressing mechanism 32 having a cylindrical shape is protruded and pushed down, and The positive electrode lead 11a is further radially pushed and bent to expand toward the outer periphery. Next, as shown in FIG. 7, while pressing the positive electrode lead 11 a by the first pressing mechanism 31 and the second pressing mechanism 32 of the forming shaft 30, the cylindrical third pressing mechanism 33 is made to protrude. Is pressed down, and the positive electrode lead 11a is further radially pushed and bent so as to expand toward the outer peripheral side.

Next, as shown in FIG. 8, the lead 11a radially expanded by the ring-shaped fixing ring 35 is pressed to fix the shape. Then, the first pressing mechanism 31
The third pressing mechanism 33 is removed from the battery body 2, and the lead forming is completed as shown in FIG.

In one example of the lead forming method of the present invention described above, the forming shaft 3 for forming the positive electrode lead 11a or the negative electrode lead 12a is used.
Although a case has been described where 0 is a three-stage configuration, the method of the present invention is not limited to the above example. That is, as long as it is sufficient to form the foil leads radially, a single forming shaft may be used, or a multi-stage forming shaft may be used.

During the steps of the lead forming method of the present invention shown in FIG.
From the end side of the battery body 2 opposite to the side where 0 is inserted,
A gas supply pipe 50 is inserted into the central hole 2h of the battery main body 2, and a gas, for example, a predetermined amount of compressed air, for example, 3
It is also possible to adopt a configuration in which air of 00 [liter / min] is sent. In this way, by sending compressed air from the gas supply pipe 50, the forming shaft 30
The lead 11a on the side for inserting is pushed back to the outer peripheral side,
It is possible to avoid being bent into the center hole 2h and to improve the workability of lead forming.

The tip of the gas supply pipe 50 can be of any shape as long as it does not hinder workability. However, as shown in FIG. The negative electrode lead 12a can be inserted into the center hole 2h of the main body 2 without being pulled in.

[0044]

According to the lead forming method of the present invention, when applied to a cylindrical laminated electrode body, for example, a non-aqueous electrolyte secondary battery, a large number of batteries are drawn out from both ends of the battery main body 2 substantially in the axial direction. The leaf-shaped leads,
When forming radially, the central hole 2
By inserting the forming shaft 30 having a conical tip into the h and pushing the foil-shaped lead to the outer peripheral portion to fall down and fix it, it is possible to perform reliable and quick lead forming. As a result, buckling of the foil-shaped lead can be avoided, a short circuit in the battery fabrication can be effectively prevented, and the lead forming process time can be reduced, work can be reliably performed, and automation can be performed.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view of a non-aqueous electrolyte secondary battery.

FIG. 2 shows a schematic plan view of a positive electrode and a negative electrode.

FIG. 3 shows a state diagram in which a laminated electrode body in which a positive electrode and a negative electrode are laminated with a separator interposed therebetween is wound around a shaft.

FIG. 4 is a schematic perspective view of a battery main body in which a laminated electrode body is wound into a cylindrical shape, and leads are led out from both ends to form a forest.

FIG. 5 shows a step diagram of the lead forming method of the present invention.

FIG. 6 shows a step diagram of the lead forming method of the present invention.

FIG. 7 shows a step diagram of the lead forming method of the present invention.

FIG. 8 shows a step diagram of the lead forming method of the present invention.

FIG. 9 shows a step diagram of the lead forming method of the present invention.

FIG. 10 is a schematic perspective view of a non-aqueous electrolyte secondary battery.

FIG. 11 shows a schematic plan view of a positive electrode and a negative electrode.

FIG. 12 is a state diagram in which a laminated electrode body in which a positive electrode and a negative electrode are laminated with a separator interposed therebetween is wound around an axis.

FIG. 13 is a schematic perspective view of a cylindrical laminated electrode body (battery body) in which the laminated electrode body is wound in a cylindrical shape and leads are formed from both ends.

FIG. 14 is a process chart of a conventional lead forming method.

[Explanation of symbols]

Reference Signs List 1 outer can, 2 battery body, 2h center hole, 4 positive electrode current collector, 5 negative electrode current collector, 6 top cover, 7 sub disk, 7a bulging portion, 8 fixed substrate, 8h through hole, 9
Safety valve, 10 non-aqueous electrolyte secondary battery, 11, 101 positive electrode, 11a, 101a positive electrode lead, 11b electrode foil, 11c positive electrode active material, 11d cut, 11t
Lead piece, 12, 102 Negative electrode, 12a, 102a
Negative electrode lead, 12b electrode foil, 12c negative electrode active material,
12d cut, 13,103 separator, 15,
105 laminated electrode body, 16, 106 axes, 40 safety resistor, 107 cylindrical laminated electrode body, 21 fixture, 22
Lead pressing ring, 30 forming shaft, 30a
Tip, 31 first pressing means, 32 second pressing means, 32h central hole of second pressing means, 33 third pressing means, 33h central hole of third pressing means, 50 gas supply pipe, 200 Non-aqueous electrolyte secondary battery, 201 outer can,
202 Battery body, 204 Positive electrode current collector, 206 Top cover, 207 Lead

Continuation of the front page (72) Inventor Hiroshi Miura 6-35, Kita-Shinagawa, Shinagawa-ku, Tokyo F-term in Sony Corporation (reference) 5H022 AA09 BB02 BB28 CC08 CC12 CC20 CC22 KK03 5H029 AJ14 AK02 CJ03 CJ06 DJ05

Claims (14)

[Claims] In a lead forming step of radially bending a plurality of foil-like leads derived from a cylindrical laminated electrode body in a substantially axial direction thereof, a tip portion is formed in a central hole of the cylindrical laminated electrode body. A lead forming method, wherein a forming shaft having a conical shape is inserted, and the foil lead is tilted in a radial direction from the axial direction to form the lead. 2. The step of inserting the forming shaft toward the center hole of the cylindrical laminated electrode body, wherein the step of inserting the forming shaft starts from the end of the battery body opposite to the side where the forming shaft is inserted, and the center of the cylindrical laminated electrode body. 2. The lead forming method according to claim 1, wherein a gas supply pipe is inserted into the hole, and gas flows in from the gas supply pipe. 3. The lead forming method according to claim 2, wherein a tip portion of the gas supply pipe has a conical shape. 4. In the lead forming step of bending the foil lead in the radial direction, the forming shaft comprises a multi-stage pressing mechanism combined in a coaxial circle, and the foil lead is connected to the axial center. 2. Forming by tilting in multiple stages from the direction to the radial direction.
The lead forming method according to 1. 5. In a lead forming step of bending the foil lead in a radial direction, the forming shaft comprises a multi-stage pressing mechanism combined in a coaxial circle, and the foil lead is connected to the shaft center. 3. Forming by tilting in multiple stages from the direction to the radial direction.
The lead forming method according to 1. 6. A lead forming step of bending the foil-shaped lead in a radial direction, wherein the forming shaft comprises a multi-stage pressing mechanism combined in a coaxial circular shape, wherein the center shaft is a tip end portion. Protruding a first pressing mechanism having a conical shape, and a second cylindrical member having a center hole outside the first pressing mechanism and having a center hole substantially equal in diameter to the first pressing mechanism. And a step of projecting a cylindrical third pressing mechanism whose center hole is substantially equal to the outermost diameter of the second pressing mechanism outside the second pressing mechanism. 2. The lead forming method according to claim 1, comprising: 7. A lead forming step of bending the foil-shaped lead in a radial direction, wherein the forming shaft comprises a multi-stage pressing mechanism combined in a coaxial circular shape, wherein the center shaft is a tip end portion. Protruding a first pressing mechanism having a conical shape, and a second cylindrical member having a center hole outside the first pressing mechanism and having a center hole substantially equal in diameter to the first pressing mechanism. And a step of projecting a cylindrical third pressing mechanism whose center hole is substantially equal to the outermost diameter of the second pressing mechanism outside the second pressing mechanism. 3. The lead forming method according to claim 2, comprising: 8. A step of laminating a positive electrode having a plurality of positive electrode leads and a negative electrode having a plurality of negative electrode leads via a separator to obtain a laminated electrode body; Winding around a cylindrical shaft to obtain a battery main body, a step of projecting a plurality of positive electrode leads and a plurality of negative electrode leads from both ends of the battery main body, respectively, in a central hole of the battery main body, A step of inserting a conical forming shaft, tipping at least one of the positive electrode lead and the negative electrode lead in the outer circumferential direction of the cross section of the battery body, and forming the tip radially. Lead forming method. 9. A step of inserting a conical forming shaft toward the center hole of the battery main body, wherein the end portion of the battery main body is opposite to the side where the forming shaft is inserted. 9. The lead forming method according to claim 8, wherein a gas supply pipe is inserted into a central hole of the battery main body, and gas flows from the gas supply pipe. 10. The lead forming method according to claim 9, wherein a tip portion of the gas supply pipe has a conical shape. 11. A lead forming step of bending at least one of the positive electrode lead and the negative electrode lead in a radial direction, wherein the forming shaft comprises a multi-stage pressing mechanism combined in a coaxial circle. 9. The lead forming method according to claim 8, wherein at least one of the lead and the negative electrode lead is formed in a stepwise manner from an axial direction of the electrode body to a radial direction. 12. A lead forming step of bending at least one of the positive electrode lead and the negative electrode lead in a radial direction, wherein the forming shaft comprises a multi-stage pressing mechanism combined in a coaxial circle. 10. The lead forming method according to claim 9, wherein at least one of the lead and the negative electrode lead is formed in a stepwise manner from the axial direction of the electrode main body in a radial direction. 13. A lead forming step of bending at least one of the positive electrode lead and the negative electrode lead in a radial direction, wherein the forming shaft comprises a multi-stage pressing mechanism combined in a coaxial circle. A step of projecting a first pressing mechanism having a conical tip, and a center hole outside the first pressing mechanism is made substantially equal to a diameter of the first pressing mechanism. Projecting the cylindrical second pressing mechanism; and forming a cylindrical third pressing outside the second pressing mechanism with a center hole substantially equal to the outermost diameter of the second pressing mechanism. 9. The lead forming method according to claim 8, further comprising: a step of projecting a pressing mechanism. 14. A lead forming step of bending at least one of the positive electrode lead and the negative electrode lead in a radial direction, wherein the forming shaft comprises a multi-stage pressing mechanism combined in a coaxial circle. A step of projecting a first pressing mechanism having a conical tip, and a center hole outside the first pressing mechanism is made substantially equal to a diameter of the first pressing mechanism. Projecting the cylindrical second pressing mechanism; and forming a cylindrical third pressing outside the second pressing mechanism with a center hole substantially equal to the outermost diameter of the second pressing mechanism. The method according to claim 9, further comprising a step of projecting the pressing mechanism.