JP5364512B2 - Cylindrical battery - Google Patents

Description

  The present invention relates to a cylindrical battery.

  A cylindrical battery represented by a lithium secondary battery or the like has a structure in which one of current collecting members connected to a positive electrode or a negative electrode wound around an axis is connected to a lid and the other is connected to a battery container. In general, the positive electrode is connected to the lid and the negative electrode is connected to the battery container, but some have a reverse connection structure.

  The lid and the battery container are insulated by a gasket made of rubber or the like. In this case, a structure is known in which insulation is achieved by a gasket and at the same time a lid is held. An example of a method for manufacturing such a cylindrical battery is as follows. First, a substantially V-shaped groove is formed by deforming a part of the battery container so as to protrude inward by pressing or the like on the upper side of the cylindrical container. Form. Next, a cylindrical gasket is disposed above the groove, and an outer peripheral edge of a disc-shaped lid slightly smaller than the gasket is placed thereon. Then, the battery container and the gasket are caulked in the axial direction by a press or the like, and the lid and the gasket are fixed between one side edge of the battery container and the groove. By fixing the lid, the current collecting member connected to the lid is fixed, and thereby the power generation elements including the positive electrode and the negative electrode are fixed. (For example, see Patent Document 1)

JP 2009-104979 A (FIG. 3)

  In the case of the above structure, the current collecting member is held in the axial direction of the cylindrical battery by the gasket, but is not held in the direction perpendicular to the axial direction.

The cylindrical battery according to the present invention includes an electrode group in which a positive electrode and a negative electrode are wound around an axis through a separator, and is disposed on one end side and the other end side in the axial direction of the electrode group. A pair of current collectors connected to one and the other, an electrode group and a pair of current collectors are accommodated, a battery container connected to one of the pair of current collectors, and connected to the other of the pair of current collectors And a rubber gasket interposed between the outer peripheral edge of the lid and one side edge in the axial direction of the battery container, and fixed by caulking between the outer peripheral edge of the cover and the battery container; comprising the axial vertical holding means for holding a current collecting member connected to the lid against the external force acting in a direction perpendicular to the direction, and one side edge in the axial direction of the outer peripheral edge and the battery container cover The gasket interposed between and has an upper part that covers the upper surface side of the lid and a lower part that covers the lower surface side of the lid. A part of the lower part also serves as a vertical axis holding means, the current collecting member has a cylindrical side part, and the positive electrode or the negative electrode connected to the current collecting member has a number of lead parts, A part of the lower portion is in contact with a side portion of a current collecting member to which a large number of lead portions are connected, directly or via another member .

  According to the cylindrical battery of the present invention, the current collecting member can be reliably held against an external force acting in the axial direction, and is resistant to external forces such as shock and vibration acting in a direction perpendicular to the axial direction. Can be improved.

Sectional drawing which shows one Embodiment of the cylindrical battery of this invention. FIG. 2 is an external perspective view in which a part of an electrode group of the cylindrical battery shown in FIG. 1 is cut. FIG. 2 is an exploded perspective view of the cylindrical battery shown in FIG. 1. Sectional drawing which shows the 1st process of the sealing method using the gasket in the cylindrical battery of this invention. Sectional drawing which shows the process of following FIG. Sectional drawing which shows the process of following FIG. Sectional drawing which shows the process of following FIG. The principal part sectional drawing which shows the state before showing the 1st modification of this invention and crimping. FIG. 9 is an essential part cross-sectional view showing a state after caulking, showing a post-process of FIG. 8. The principal part sectional drawing which shows the 2nd modification of this invention and shows the state before crimping. FIG. 11 is a main part sectional view showing a state after caulking, showing a post-process of FIG. 10.

(Structure of cylindrical battery)
Hereinafter, an embodiment of a cylindrical battery of the present invention will be described with reference to the drawings by taking a lithium secondary battery as an example.
FIG. 1 is a cross-sectional view showing an embodiment of a cylindrical battery according to the present invention. FIG. 2 is a perspective view of an external appearance of a part of the electrode group of the cylindrical battery shown in FIG. 3 is an exploded perspective view of the cylindrical battery shown in FIG. However, in FIG. 3, the negative electrode current collector plate and the battery container are not shown.
The cylindrical battery 1 has dimensions of, for example, an outer diameter of 40 mmφ and a height of 100 mm.
This cylindrical battery 1 accommodates each component for power generation described below in a cylindrical battery container 2 with a bottom and a hat-shaped lid 3. The battery container 2 is deformed so that the open side portion protrudes inward, and a groove 2a is formed.

  Reference numeral 10 denotes an electrode group. As illustrated in FIG. 2, the electrode group 10 includes a shaft core 15, a positive electrode sheet (positive electrode) 11 wound around the shaft core 15, a negative electrode sheet (negative electrode) 12, and a positive electrode sheet 11 and a negative electrode sheet. 12 and a separator 13 disposed between the two.

  The positive electrode sheet 11 is formed of an aluminum foil, and a positive electrode processing portion 11a that has been subjected to a positive electrode treatment for applying a positive electrode active material or the like on both sides; Have A large number of positive electrode leads (lead portions) 11b1 are integrally formed at equal intervals in the positive electrode untreated portion 11b.

To describe an example of a method of forming a positive electrode sheet 11, the positive electrode sheet 11, using a typical lithium manganate (LiMn ₂ O ₄₎ as a positive electrode active material as a lithium-manganese complex oxide is prepared in the following manner . 10 parts by weight of flake graphite as a conductive agent and 5 parts by weight of polyvinylidene fluoride (PVDF) as a binder are added to 90 parts by weight of the positive electrode active material, and N-methyl-2 is used as a dispersion solvent. -The slurry in which pyrrolidone is added and kneaded is uniformly applied to both sides of an aluminum foil having a thickness of 20 µm, dried, then pressed and cut.

  The negative electrode sheet 12 is formed of a copper foil, and a negative electrode treatment portion 12a that has been subjected to a negative electrode treatment for applying a negative electrode active material or the like on both sides; Have In the negative electrode untreated portion 12b, a large number of negative electrode leads (lead portions) 12b1 are integrally formed at equal intervals.

  If an example of the formation method of the negative electrode sheet 12 is demonstrated, the negative electrode sheet 12 will be produced as follows using an amorphous carbon powder as a carbon material of a negative electrode active material. A slurry obtained by adding 10 parts by weight of polyvinylidene fluoride (PVDF) as a binder to 90 parts by weight of amorphous carbon powder, and adding and kneading N-methyl-2-pyrrolidone as a dispersion solvent to this is 10 μm thick. After uniformly applying to both sides of the rolled copper foil and drying, it is pressed and cut.

The separator 13 is, for example, a polyethylene porous film having a thickness of 40 μm.
The shaft core 15 has a hollow thin cylindrical shape extending in the axial direction (vertical direction in the drawing), and a positive electrode current collecting member 31 is press-fitted into the upper portion thereof. The positive electrode current collecting member 31 is formed of, for example, aluminum, and has a lower cylindrical portion 31b that is formed on the shaft core side of the disc-shaped base portion 31a so as to protrude from the lower surface side and press-fitted into the inner surface of the shaft core 15. It has an upper cylinder part (side part) 31c protruding to the upper surface side on the outer peripheral edge.

All the positive electrode leads 11 b 1 of the positive electrode sheet 11 are welded to the upper cylindrical portion 31 c of the positive electrode current collecting member 31. That is, as illustrated in FIG. 3, the positive electrode lead 11 b 1 is overlapped and joined to the upper cylindrical portion 31 c of the positive electrode current collecting member 31. Since each positive electrode lead 11b1 is very thin, a large current cannot be taken out by one. For this reason, a large number of positive electrode leads 11b1 are formed at predetermined intervals over the entire length from the start of winding to the shaft core 15 to the end of winding.
Since the positive electrode current collecting member 31 is oxidized by the electrolytic solution, the reliability can be improved by forming it with aluminum. As soon as the surface of aluminum is exposed by some processing, an aluminum oxide film is formed on the surface, and this aluminum oxide film can prevent oxidation by the electrolytic solution.
Further, by forming the positive electrode current collecting member 31 from aluminum, the positive electrode lead 11b1 of the positive electrode sheet 11 can be welded by ultrasonic welding or spot welding.

The negative electrode current collecting member 21 (see FIG. 1) is formed of, for example, copper, and has an inner peripheral cylindrical portion 21b that is press-fitted into the outer surface of the shaft core 15 on the shaft core side of the disc-shaped base portion 21a. The outer peripheral cylindrical portion 21c protrudes in the same direction as the inner peripheral cylindrical portion 21b.
All of the negative electrode leads 12b1 of the negative electrode sheet 12 are welded to the outer peripheral cylindrical portion 21c of the negative electrode current collecting member 21 by ultrasonic welding or spot welding. Since each negative electrode lead 12b1 is very thin, a large number of negative leads 12b1 are formed at predetermined intervals over the entire length from the start of winding to the shaft core 15 to take out a large current.

The negative electrode lead 12b1 of the negative electrode sheet 12 and the ring-shaped pressing member 22 are welded to the outer periphery of the outer peripheral cylindrical portion 21c of the negative electrode current collecting member 21. Since there are a large number of the negative electrode leads 12b1, they are brought into close contact with the outer periphery of the outer peripheral cylindrical portion 21c of the negative electrode current collecting member 21, and the holding member 22 is wound around the outer periphery of the negative electrode lead 12b1 to be temporarily fixed and welded in this state.
A negative electrode conducting lead 23 made of copper is welded to the lower surface of the negative electrode current collecting member 21.
The negative electrode conducting lead 23 is welded to the battery container 2 at the bottom of the battery container 2. The battery container 2 is formed of, for example, carbon steel having a thickness of 0.5 mm, and the surface thereof is plated with nickel. By using such a material, the negative electrode energizing lead 23 can be welded to the battery container 2 by resistance welding.

FIG. 7 is an enlarged view of a region A of the cylindrical battery 1 shown in FIG. In the following description, please refer to FIG. 7 together with FIGS.
The positive electrode lead 11b1 of the positive electrode sheet 11 and the ring-shaped pressing member 32 are welded to the outer periphery of the upper cylindrical portion 31c of the positive electrode current collecting member 31. Since there are a large number of positive electrode leads 11b1, they are brought into close contact with the outer periphery of the upper cylindrical portion 31c of the positive electrode current collecting member 31, and the holding member 32 is wound around the outer periphery of the positive electrode lead 11b1 and temporarily fixed, and welding is performed in this state.
A large number of positive leads 11 b 1 formed on the positive electrode sheet 11 constituting the electrode group 10 are welded to the upper cylindrical portion 31 c of the positive electrode current collector 31, so that the positive electrode current collector 31 is integrated with the electrode group 10. Composed.

  A first flexible connection member 33 formed by laminating a number of aluminum foils is joined to the upper surface of the base portion 31a of the positive electrode current collecting member 31 by welding a part thereof. The first flexible connecting member 33 can flow a large current by laminating and integrating a large number of aluminum foils, and is provided with flexibility. In other words, it is necessary to increase the thickness of the connecting member in order to pass a large current, but if it is formed of a single metal plate, the rigidity increases and the flexibility is impaired. Therefore, a large number of aluminum foils having a small thickness are laminated to give flexibility. The reason why the first flexible member 33 is required to be flexible will be described later.

As shown in FIG. 3, a ring-shaped insulating plate 41 made of an insulating resin material having a circular opening 41 a is mounted on the upper cylindrical portion 31 c of the positive electrode current collecting member 31.
The insulating plate 41 has an opening 41a and a side portion 41b protruding downward.
An aluminum inner lid 35 is fitted in the opening 41 a of the insulating material 41. A part of the second flexible connecting member 34 is welded to the inner lid 35 on the lower surface of the inner lid 35. The second flexible member 34 can flow a large current by laminating and integrating a large number of aluminum foils, and is provided with flexibility.

As shown in FIG. 3, the first flexible connecting member 33 and the second flexible connecting member 34 are fixed at one end side by welding, as shown in FIG. 3, before the electrolyte is injected into the battery container 2. The other end side is an open end. After injecting the electrolytic solution, the open ends of the first flexible connecting member 33 and the second flexible connecting member 34 are welded together as shown in FIG.
An opening 36 for welding the first flexible member 33 and the second flexible member 34 is formed in the inner lid 35.

Above the inner lid 35, there is disposed a cleavage valve 37 made of aluminum or the like whose peripheral portion is placed on the insulating plate 41 and whose central portion is in contact with the upper surface of the inner lid 35. The cleavage valve 37 has a cut 37a. The cleavage valve 37 is provided for ensuring the safety of the battery. When the internal pressure of the lithium battery increases, the cleavage valve 37 warps upward and is separated from the inner lid 35 to cut off the current supply as the first stage. As a second stage, when the internal pressure still rises, it has a function of cleaving at the cut 37a and releasing the internal gas.
The insulating plate 41 described above is interposed between the outer peripheral portion of the inner lid 35 and the peripheral edge side of the cleavage valve 37, so that only the central portion of the cleavage valve 37 is in contact with the inner lid 35 in the initial state.

A lid 3 is disposed on the upper surface of the cleavage valve 37. The lid 3 is formed of iron such as carbon steel plated with Ni, and has a disk-shaped peripheral portion 3a that contacts the cleavage valve 37 and a headless and bottomless cylindrical portion that protrudes upward from the peripheral portion 3a. It has a hat shape with 3b. A plurality of openings 3c are formed in the cylindrical portion 3b.
The upper and lower surfaces and outer peripheral side surfaces of the peripheral edge 3 a of the lid 3 are covered with the peripheral edge of the cleavage valve 37. The cleavage valve 37 is initially formed in a shape having a side wall 37b standing perpendicular to the disc-shaped base as shown in FIG. 3, and after the peripheral edge 3a of the lid 3 is mounted, It is caulked by a press or the like and is bent in a U shape so as to cover the upper surface side of the peripheral edge portion 3 a of the lid 3.
In addition, when the lid | cover 3 is formed with iron, when joining in series with another cylindrical battery, it can weld by another cylindrical battery formed with iron by spot welding.

A gasket 43 is provided to cover the upper and lower surfaces and the outer peripheral surface of the peripheral edge of the cleavage valve 37. As shown in FIG. 3, the gasket 43 initially includes an outer peripheral wall 43 b that is erected upward on the peripheral edge of the ring-shaped base 43 a, and an inner peripheral side that extends downward from the base 43 a. And a cylindrical portion 43c that is formed to hang substantially perpendicularly.
As will be described in detail later, the outer peripheral wall portion 43b of the gasket 43 is bent by a press or the like, and is processed so as to press the cleavage valve 37 and the lid 3 in the axial direction by the base portion 43a and the outer peripheral wall portion 43b. . At the same time, the corner 43d (FIG. 7) at the boundary between the base 43a and the cylinder 43c of the gasket 43 is brought into contact with the upper cylinder 31c of the positive current collector 31 so that the positive current collector 31 is axially moved. To move in the direction perpendicular to the. In other words, the positive electrode current collecting member 31 is held against an external force acting in the direction perpendicular to the axis.

A predetermined amount of non-aqueous electrolyte is injected into the battery container 2. As an example of the non-aqueous electrolyte, six electrolytes may be used in a mixed organic solvent in which ethylene carbonate (EC), dimethyl carbonate (DMC), and diethyl carbonate (DEC) are mixed at a volume ratio of 1: 1: 1. An example is one obtained by dissolving 1 mol / liter of lithium fluorophosphate (LiPF ₆ ).
Hereinafter, an example of a manufacturing method of the cylindrical battery having the above-described configuration will be described.

(Cylindrical battery manufacturing method)
A positive electrode sheet 11 having a positive electrode processing part 11a and a positive electrode unprocessed part 11b on which a large number of positive electrode leads 11b1 are formed is produced. Further, the negative electrode sheet 12 on which the negative electrode processing part 12a and a large number of negative electrode leads 12b1 are formed is prepared.
The electrode group 10 is produced by winding the positive electrode sheet 11 and the negative electrode sheet 12 around the shaft core 15 with the separator 13 between the two sheets.

  A negative electrode current collecting member 21 is attached to the lower portion of the shaft core 15 of the electrode group 10. The negative electrode current collector 21 is attached by fitting the inner peripheral cylinder portion 21 b of the negative electrode current collector 21 into the outer periphery of the shaft core 15. The negative electrode lead 12b1 is distributed almost uniformly around the entire periphery of the outer peripheral cylindrical portion 21c of the negative electrode current collecting member 21, and the presser member 22 is wound around the outer periphery of the negative electrode lead 12b1. Then, the negative electrode lead 12b1 and the presser ring 22 are welded to the negative electrode current collecting member 21 by ultrasonic welding or the like.

  A positive electrode current collecting member 31 having one end of the first flexible connecting member 33 welded to the upper surface side is attached to the upper portion of the shaft core 15. Spot welding can be used for welding of the first flexible connecting member 33 and the positive electrode current collecting member 31. The positive current collector 31 is attached to the shaft core 15 by fitting the lower cylindrical portion 31 b of the positive current collector 31 to the inner surface of the shaft 15.

  The positive electrode lead 11b1 is distributed almost uniformly around the entire circumference of the upper cylindrical portion 31c of the positive electrode current collecting member 31, and the presser member 32 is wound around the outer periphery of the positive electrode lead 11b1. Then, the positive electrode lead 11b1 and the presser ring 32 are welded to the positive electrode current collecting member 31 by ultrasonic welding or the like. In this way, the power generation unit 20 illustrated in FIG. 3 is produced.

The power generation unit 20 produced through the above-described steps is accommodated in a metal bottomed cylindrical member having a size that can accommodate the power generation unit 20. Although it is not necessary to add, the bottomed cylindrical member is the battery container 2.
Hereinafter, in order to simplify and clarify the description, this bottomed cylindrical member will be described as the battery container 2.
The negative electrode conducting lead 22 of the power generation unit 20 housed in the battery container 2 is welded to the battery container 2 by resistance welding.
Next, the battery container 2 is drawn, a part of the battery container 2 protrudes inward, and a substantially V-shaped groove 2a is formed on the outer surface. The groove 2 a of the battery container 2 is formed so as to be positioned in the upper end portion of the power generation unit 20, in other words, in the vicinity of the upper end portion of the positive electrode current collector 31.

A predetermined amount of electrolyte is injected into the battery container 2 in which the power generation unit 20 is accommodated.
When injecting the electrolytic solution, the first flexible connecting member 33 is bent at a position that does not interfere with the injection. Further, after the injection of the electrolytic solution is finished, it is deformed and its open end is arranged at a position corresponding to the opening 36 of the inner lid 35.

An inner lid 35 to which one end of the second flexible connecting member 34 is welded is attached to the insulating plate 41 and disposed on the positive electrode current collecting member 31. For welding of the second flexible connecting member 34 and the inner lid 35, ultrasonic welding can be used. The inner lid 35 and the insulating plate 41 are attached by press fitting, welding, adhesion, or the like. The positive electrode current collector 31 is placed on the upper cylinder part 31c of the positive electrode current collector 31 with the inner surface of the upper cylinder part 31c of the positive electrode current collector 31 fitted into the side part 41b of the insulating plate 41. Put.
The open end portion of the second flexible connection member 34 is positioned at a position corresponding to the opening portion 36 of the inner lid 35 and overlapped with the open end portion of the first flexible connection member 31.

  The open ends of the first flexible connection member 33 and the second flexible connection member 34 are welded together by spot welding or the like. When welding the first flexible connection member 33 and the second flexible connection member 34, as described above, the first flexible connection member 33 and the second flexible connection member 34 are deformed in order to displace the positions of the respective open ends. However, since each is formed by laminating a plurality of thin metal foils such as aluminum foils, it has sufficient flexibility for deformation.

Next, the lid 3 to which the cleavage valve 37 is fixed is placed on the insulating plate 41. The cleavage valve 37 and the lid 3 are fixed by caulking or the like. As shown in FIG. 3, since the side wall 37 b is initially formed perpendicular to the base portion 37 a in the cleavage valve 37, the peripheral edge portion 3 a of the lid 3 is disposed in the side wall 37 b of the cleavage valve 37. Then, the side wall 37b of the cleavage valve 37 is deformed by a press or the like so as to cover the upper and lower surfaces and the outer peripheral side surface of the peripheral edge of the lid 3 and press-contact.
Thereafter, the lid 3 and the battery container 2 are crimped, and the gasket 3 holds the lid 3, in other words, the positive electrode current collecting member 31 and the electrode group 10 in the axial direction, and the positive electrode current collecting member 31 is set in the axial direction. Processing to ensure that the vertical direction is maintained.
The method will be described with reference to FIGS. 4 to 7 showing an enlarged cross section of the region A shown in FIG.

  As shown in FIG. 4, a gasket 43 is disposed between the lid 3 to which the cleavage valve 37 is fixed by caulking and the battery container 2. The gasket 43 is formed of rubber and is not intended to be limited, but an example of one preferred material is ethylene propylene copolymer (EPDM). For example, when the battery container 2 is made of carbon steel having a thickness of 0.5 mm and the outer diameter is 40 mmΦ, the thickness of the gasket 43 is about 10 mm.

  In the state illustrated in FIG. 4, the gasket 43 remains inside the groove 2 a of the battery container 2. In addition, the position of the upper end of the power generation unit 20 corresponds to the upper part of the groove 2 a of the battery container 2.

  As described above, the gasket 43 is initially formed in a shape having the outer peripheral wall portion 43b above the base portion 43a on the ring and the cylindrical portion 43c projecting downward in the vertical direction to the base portion 43a. The outer peripheral wall 43b is also formed so as to protrude in a substantially vertical direction with respect to the base 43a. In this state, a radial clearance C1 exists between the positive electrode current collecting member 31 and the cylindrical portion 43c of the gasket 43, and a radial clearance C2 exists between the holding member 32 and the cylindrical portion 43c of the gasket 43. To do.

As shown in FIG. 4, with the lid 3 on which the cleavage valve 37 is caulked mounted on the gasket 43, as shown in FIG. The molding die 61 is pushed down in the axial direction of the battery container 2, and the outer peripheral wall 43 b of the gasket 43 is inclined inward along with the upper side edge of the battery container 2. As described above, when the outer peripheral wall portion 43b of the gasket 43 is inclined inward by pressing, the tube portion 43c of the gasket 43 rotates counterclockwise with respect to the axial direction.
The press working may be performed a plurality of times by changing from a press surface whose inclination is nearly vertical to a molding die whose inclination is gradually lowered so as to approach the horizontal.

FIG. 6 shows a state of a process of caulking the lid 3 and the gasket 43 using a molding die 62 having a horizontal press surface. In this step, a molding die 63 inclined at substantially the same angle as the inclined surface of the groove 2 a is disposed in the groove 2 a of the battery container 2, and the cleavage valve 37 is caulked between the molding dies 62 and 63. The lid 3 is caulked by compressing the gasket 43 and the upper side edge of the battery container 2 in the axial direction. By this caulking, the outer peripheral wall portion 43 b of the gasket 43 is bent in an L shape along the upper surface and outer peripheral side surface of the cleavage valve 37.
When compressed in this way, an internal stress is generated in the gasket 43, and the gasket 43 causes the base 43a and the outer peripheral wall 43b to extend in a direction perpendicular to the compression direction. For this reason, the clearance c1 between the positive electrode current collecting member 31 and the cylindrical portion 43c of the gasket 43 and the clearance c2 between the holding member 32 and the cylindrical portion 43c of the gasket 43 are both larger than those before the processing shown in FIG. Get smaller.

FIG. 7 shows a state further compressed in the axial direction from the state of FIG.
In this state, the upper side edge of the battery container 2 bites into the upper surface of the gasket 43.
Further, the base portion 43a and the outer peripheral wall portion 43b of the gasket 43 further extend in a direction perpendicular to the compression direction, and the corner portion 43d at the boundary portion between the base portion 43a and the cylindrical portion 43c is the outer surface of the upper cylindrical portion 31c of the positive electrode current collecting member 31. Abut. At the same time, the cylindrical portion 43 c of the gasket 43 is in close contact with the pressing member 32.
In this way, the lid 3 is held by the battery container 2 and the gasket 43, whereby the positive electrode current collecting member 31 and the electrode group 10 are firmly held in the direction perpendicular to the axial direction. Further, the corner portion 43d of the gasket 43 is in strong contact with the outer surface of the upper cylindrical portion 31c of the positive electrode current collecting member 31, so that the positive electrode current collecting member 31 and the electrode group 10 integrated with the positive electrode current collecting member 31 are It is firmly held in the direction perpendicular to the axial direction.
In the above description, the gasket 43 does not need to be in contact with or in close contact with the positive electrode current collecting member 43 and the pressing member 32, but only with respect to either one.

Table 1 shows the number of internal short-circuit occurrences after the gasket 43 is made of EPDM and the vibration test is performed using the Shore hardness Hs as a parameter.
Each of Examples 1 to 5 has the structure of the cylindrical battery illustrated in FIG. 1, and the Shore hardness Hs of the gasket 43 is 50 degrees, 60 degrees, 70 degrees, 80 degrees, and 90 degrees, respectively. is there. Further, as a comparative example, a cylindrical battery having a conventional structure having a clearance between the gasket and the positive electrode current collector and using an EPDM gasket having a shore hardness Hs of 70 degrees is manufactured, and the same vibration is produced. Post the results of the test.

The vibration test is in accordance with “JISC8713 sealed small secondary battery mechanical test” with a vibration frequency of 10 to 500 Hz, an amplitude of 0.35 mm peak or a maximum of 50 m / s ² , and the vibration axis is a cylinder whose effect is easy to verify. The direction perpendicular to the longitudinal (axis) direction was taken. The sweep rate was 1 octave / minute and repeated up to 100 cycles. The voltage was measured every 20 cycles to check for the presence of internal short circuits, and the number of internal short circuits in each battery was counted. The battery voltage was 2.7 V in the initial stage, the battery voltage was measured every 20 cycles, and the battery whose battery voltage was 2.5 V or less was regarded as an internal short circuit. In the test, 20 batteries were used for each example. The ambient temperature is 20 + 0.5-0.5 ° C. The number of internal short-circuit occurrences shown in Table 1 is a cumulative number.

  As listed in Table 1, in the comparative example, a battery in which an internal short circuit occurred from 40 cycles was confirmed, and in 60 cycles, an internal short circuit occurred in 7 batteries. In addition, at the end of 100 cycles, 19 of the total number of 20 were almost all, and an internal short circuit occurred. On the other hand, in all of Examples 1 to 5, none of the batteries generated an internal short circuit until 60 cycles. Therefore, it was confirmed that the reliability of each of the examples was improved with respect to the comparative example. Among them, in Examples 2 to 4 (Hs 60 to 80), there was no battery that caused a short circuit even after the end of 100 cycles.

Therefore, from the results in Table 1, it can be said that the Shore hardness Hs is most preferably 60 to 80 degrees. However, it should be considered that the optimum value of Hs varies depending on the clearance between the positive electrode current collecting member 31 and the gasket 43 in the initial state and the compressive force of the press.
As described above, according to the above embodiment, the positive electrode current collecting member 31 is strengthened against the external force acting in the axial direction by caulking the battery container 2 and the gasket 43 with the peripheral edge portion 3a of the lid 3 interposed therebetween. Hold. Further, the corner 43d at the boundary between the base 43a of the gasket 43 and the cylinder 43c is brought into contact with the upper cylinder 31c of the positive current collector 31 so that the positive current collector 31 and the positive current collector 43 are integrated with each other. The configured electrode group 10 can be securely held against external forces such as impact and vibration acting in a direction perpendicular to the axial direction, and durability can be improved.
In the above-described embodiment, the positive electrode current collector 31 is a method of performing the holding of the positive electrode current collector 31 in the axial direction and the vertical direction of the axis by the gasket 43 simultaneously. The axial holding of 31 and the holding in the direction perpendicular to the axis may be performed in separate steps. Next, such a modification is shown.

(Modification 1)
FIGS. 8 and 9 are cross-sectional views showing main parts of a first modification of the embodiment. FIG. 8 shows a state before caulking, and FIG. 9 shows a state after caulking. In the following description, the same members as those in the embodiment are denoted by the same reference numerals, and the description thereof is omitted.
8 and 9, the configuration different from the embodiment is that the first groove 2 a 1 and the second groove 2 a 2 are formed in the battery container 2, and that the positive electrode lead 11 b 1 welded to the positive electrode current collecting member 31 is formed. That is, there is no presser member 32 wound around.
When the outline of the process up to FIG. 8 is shown, like the case of the embodiment, after the power generation unit 20 is accommodated in the battery container 2, the first groove 2 a 1 is positioned at a position corresponding to the upper part of the gasket 43, and The second groove 2a2 is formed at a position corresponding to the lower portion of the gasket 43 simultaneously or by a separate process.

  After placing the lid 3 on which the gasket 43 and the cleavage valve 37 are caulked on the insulating plate 41, first, using the first groove 2a1, as in the case of the embodiment, by the press or the like, the cleavage valve 37 is used. The battery container 2 and the gasket 43 are compressed in the axial direction with the peripheral edge portion 3a of the lid 3 interposed therebetween. However, unlike the case of the embodiment, the compression of the battery container 2 remains in a state where the cylindrical portion 43 c of the gasket 43 does not contact the positive electrode lead 11 b 1 welded to the positive electrode current collecting member 31. That is, the first processing step in the first modification is performed to hold the positive electrode current collecting member 31 so as not to move in the axial direction.

Next, the second groove 2a2 of the battery container 2 is further deformed so as to protrude inward by a press or the like. As shown in FIG. 9, by this second processing step, the portion 2 b corresponding to the tip of the second groove 2 a 2 of the battery container 2 presses the cylindrical portion 43 c of the gasket 43, and the positive electrode current collecting member The positive electrode lead 11 b 1 welded to 31 is brought into contact with the positive electrode lead 11 b 1.
In this case, in FIG. 9, the cylinder part 43c of the gasket 43 is rotated clockwise with respect to the axial direction, contrary to the case of the embodiment. And the front end part side of the cylinder part 43c of the gasket 43 contact | abuts to the upper cylinder part 31c of the positive electrode current collection member 31, and hold | maintains the positive electrode current collection member 31 against the external force perpendicular | vertical to an axial direction.

  Also in the case of the modification 1, the same effect as the case of embodiment can be show | played. In addition, the process of holding the positive electrode current collector plate 31 in the axial direction using the first groove 2a1 of the battery case 2, and the positive electrode current collector plate 31 in the axial direction using the second groove 2a2 of the battery case 2 Since the process of holding in the vertical direction is performed in a separate process, each gasket 43 can be processed with an appropriate load. Therefore, the positive current collector 31 can be fixed with higher accuracy and reliability.

(Modification 2)
FIGS. 10 and 11 are cross-sectional views showing a main part of a second modification of the embodiment. FIG. 10 shows a state before caulking, and FIG. 11 shows a state after caulking. Also in the second modification, the same members as those in the embodiment are denoted by the same reference numerals, and the description thereof is omitted.
Also in the second modification shown in FIGS. 10 and 11, the first groove 2 a 1 and the second groove 2 a 2 are formed in the battery container 2 as in the first modification. However, in the first modification, compared to the structure in which the holding member 32 fitted around the positive electrode lead 11b1 welded to the positive electrode current collecting member 31 is not provided, in the second modification, the positive electrode lead 11b1 has a structure. Around the periphery, for example, a rubber ring 44 such as EPDM is mounted.

The ring 44 is attached in close contact with the outer surface of the positive electrode lead 11 b 1 welded to the positive electrode current collector 31 before the power generation unit 20 is accommodated in the battery container 2.
Referring to the outline of the process up to FIG. 10, after the power generation unit 20 with the ring 44 mounted around the positive electrode lead 11b1 is accommodated in the battery container 2, the first groove 2a1 and the second groove 2a2 are formed. .

  Then, by using the first groove 2a1, the battery container 2 and the gasket 43 are compressed in the axial direction by a press or the like so that the gasket 43 does not contact the positive electrode lead 11b1 welded to the positive electrode current collecting member 31. This first processing is performed to hold the positive electrode current collecting member 31 so as not to move in the axial direction, as in the first modification.

Next, the second groove 2a2 of the battery case 2 is deformed by a press or the like so as to protrude further inward. As shown in FIG. 11, due to this deformation, the portion 2 b corresponding to the tip of the second groove 2 a 2 of the battery container 2 comes into contact with the cylindrical portion 43 c of the gasket 43.
And the cylinder part 43c of the gasket 43 contact | abuts to the ring 44 in the position rotated slightly clockwise with respect to the axial direction. The ring 44 is pressed by the gasket 43 to press the positive current collector 31 and holds the positive current collector 31 against an external force perpendicular to the axial direction.

  Also in the case of the modification 2, the effect similar to embodiment can be show | played. Similarly to the first modification, the positive electrode current collecting plate 31 is held in the axial direction using the first groove 2a1 of the battery container 2, and the positive electrode current collector is used using the second groove 2a2 of the battery container 2. Since the process of holding the plate 31 in the direction perpendicular to the axial direction is performed in a separate process, the gasket 43 can be processed with an appropriate load. Moreover, in the case of the second modification, the structure is such that the positive electrode current collecting plate 31 is held via a rubber ring 44, and the rubber having the optimum value for the Shore hardness of the rubber can be freely used regardless of the gasket 43. You can choose. Therefore, the positive electrode current collecting plate 31 can be held with high accuracy and high reliability.

  In the above embodiment, the case of a lithium battery has been described. However, the present invention is not limited to a lithium battery, and may be applied to other cylindrical batteries such as a nickel metal hydride battery and a nickel cadmium battery. Can do.

  In the above embodiment, the case where the positive electrode current collecting member 31 is held by the gasket is shown. However, the negative electrode current collecting member can be held by the gasket. In a cylindrical battery having a current collecting member as a negative electrode, a lid connected to the negative electrode current collecting member is formed of an iron material such as carbon steel, and a battery container as a positive electrode is formed of aluminum. That is, in FIG. 1, the lead (positive electrode) 12b1, the current collecting member (positive electrode) 21, the current collecting lead (positive electrode) 22 and the battery container 2 are formed of aluminum, and the lead (negative electrode) 11b1 is formed of copper. The member (negative electrode) 31, the inner lid 35, the cleavage valve 37, and the lid 3 are formed of iron such as carbon steel. The lid 3 may be formed of aluminum. However, even in this case, the material is an example, and the material formed of other materials is also included in the present invention.

  In addition, the cylindrical battery of the present invention can be variously modified and configured within the scope of the invention. In short, the positive electrode and the negative electrode are wound around the shaft core via the separator. An electrode group, a pair of current collecting members disposed on one end side and the other end side in the axial direction of the electrode group, respectively connected to one and the other of the positive electrode and the negative electrode, and an electrode group and the pair of current collecting members A battery container housed and connected to one of the pair of current collecting members; a lid connected to the other of the pair of current collecting members; and an outer peripheral edge of the lid and one side edge in the axial direction of the battery container And a rubber gasket fixed by a pressure contact force acting on the outer peripheral edge of the lid and the battery container in the axial direction, and a collector connected to the lid against the external force acting in a direction perpendicular to the axial direction. What is necessary is just to comprise the axial perpendicular direction holding means holding an electric member.

DESCRIPTION OF SYMBOLS 1 Cylindrical battery 2 Battery container 2a Groove 2a1 1st groove 2a2 2nd groove 3 Lid 3a Peripheral part 3b Tube part 10 Electrode group 11 Positive electrode sheet (positive electrode)
11a Positive electrode processing part 11b Positive electrode non-processing part 11b1 Positive electrode lead 12 Negative electrode sheet (negative electrode)
12a Negative electrode processing part 12b Negative electrode unprocessed part 12b1 Negative electrode lead 13 Separator 15 Core 20 Power generation unit 21 Negative electrode current collecting member 31 Positive electrode current collecting member 35 Inner lid 37 Cleavage valve 41 Insulating plate 43 Gasket 43a Base part 43b Outer peripheral wall part 43c Tube part 44 rings

Claims (3)

An electrode group in which a positive electrode and a negative electrode are wound around an axis through a separator;
A pair of current collecting members disposed on one end side and the other end side in the axial direction of the electrode group, respectively connected to one and the other of the positive electrode and the negative electrode;
A battery container containing the electrode group and the pair of current collecting members and connected to one of the pair of current collecting members;
A lid connected to the other of the pair of current collecting members;
A rubber gasket interposed between the outer peripheral edge of the lid and one side edge in the axial direction of the battery container, and fixed by caulking between the outer peripheral edge of the lid and the battery container;
Comprising the axial vertical holding means against the external force acting in the axial direction perpendicular to retain the current collector member connected to the lid, a,
The gasket interposed between the outer peripheral edge of the lid and one side edge of the battery container in the axial direction has an upper portion covering the upper surface side of the lid and a lower portion covering the lower surface side of the lid, A part of the lower part also serves as the axial vertical direction holding means,
The current collecting member has a cylindrical side portion, the positive electrode or the negative electrode connected to the current collecting member has a number of lead portions, and a part of the lower portion of the gasket is connected to the number of lead portions. A cylindrical battery, wherein the cylindrical battery is in contact with a side portion of the current collecting member directly or via another member . 2. The cylindrical battery according to claim 1 , wherein a lower portion of the gasket includes a ring-shaped base portion and a cylindrical portion formed substantially perpendicular to the ring-shaped base portion, and the base portion and the cylindrical portion. However, the cylindrical battery is in contact with the current collecting member while being inclined in the axial direction. 3. The cylindrical battery according to claim 1, wherein the gasket has a Shore hardness of Hs 50 to 90 degrees.