JP4501361B2 - Secondary battery - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a secondary battery having a structure suitable for constituting a battery with a high capacity and high output of 5 A / h or more.
[0002]
[Prior art]
As for the batteries that serve as the power source for electric vehicles and hybrid vehicles that use both internal combustion engines and electric motors, power supply devices using lead-acid batteries or nickel-hydrogen batteries are currently in practical use. There is a demand for higher capacity and higher output, and lithium ion secondary batteries are expected as batteries that realize this. However, lithium ion secondary batteries are high energy density batteries that use flammable non-aqueous electrolytes. Therefore, when an electrical failure such as overcharge or external short circuit occurs, the current circuit is quickly shut off. It is necessary to provide a structure to Further, when the battery temperature rises due to some cause and the pressure inside the battery rises, it is necessary to provide a structure that releases the abnormal internal pressure to the outside and shuts off the current circuit before it reaches the limit pressure.
[0003]
FIG. 8 shows a configuration of discharge of abnormal internal pressure and current interruption in a lithium-ion secondary battery according to the prior art, and there is an abnormality in the sealing plate 62 that seals the opening of the cylindrical outer case 61 containing the power generation element. An internal pressure release structure and a current interruption structure are provided.
[0004]
The sealing plate 62 includes a cap 68 serving as an electrode terminal, a PTC element 67 formed in a ring shape, and a peripheral portion where a thin plate serving as an explosion-proof valve 66 is overlapped with an inner gasket 69, The disk holder 64 is folded together and caulked with a thin plate to be integrated. The sealing plate 62 seals the opening of the outer case 61 by being caulked and fixed to the outer case 61 via an outer gasket 63. The explosion-proof valve 66 is formed with an easily breakable portion 66a formed in a thin C shape and is welded to the current cut-off valve 65 at a welding point A at the center portion bulged toward the inside of the battery. Since the disk holder 64 is joined with the positive or negative lead drawn from the electrode plate group, the current circuit is capped from the disk holder 64 through the current cutoff valve 65, from the welding point A through the explosion-proof valve 66, and the PTC element 67. 68, and the cap 68 serves as a positive or negative terminal.
[0005]
When the secondary battery having the sealing plate 62 configured as described above is heated to a high temperature due to overcharge or external heating, the reaction between the positive and negative electrode active materials and the electrolytic solution, the evaporation of the electrolytic solution, Gas is generated by decomposition and the like, and an abnormal reaction is accelerated due to heat generated by them, and the pressure in the outer case 61 abnormally increases due to further temperature rise. The pressure rise in the outer case 61 extends from the opening formed in the disk holder 64 to the current cutoff valve 65 and pushes the current cutoff valve 65 outward, so that the increased internal pressure acts on the explosion-proof valve 66 welded thereto. To do. When the pushing-up pressure applied to the explosion-proof valve 66 exceeds a predetermined pressure, the bulging portion of the explosion-proof valve 66 is reversed, so that the welding with the current cutoff valve 65 at the welding point A is broken and the explosion-proof valve 66 and the current cutoff valve 65 are broken. When the connection between and the current circuit is cut off, the current circuit is cut off, and when the cause of the temperature rise is an electrical cause such as overcharging, the causal factor is eliminated. When the cause of the temperature rise is not electrical or when the internal pressure further rises, the explosion-proof valve 66 is broken from the easily breakable portion 66a, so that the gas in the outer case 61 is opened in the cap 68. The outer case 61 is prevented from being broken because it is discharged from the outside.
[0006]
A number of proposals have been made on the secondary battery in which the current interrupting structure and the explosion-proof structure as described above are provided on the sealing plate in addition to the one proposed by the present applicant (see Patent Document 1) (Patent Document 2). reference).
[0007]
[Patent Document 1]
Japanese Unexamined Patent Publication No. 09-129195 (pages 2 and 3, FIG. 1)
[0008]
[Patent Document 2]
Japanese Patent Laid-Open No. 08-315798 (pages 3 to 4, FIG. 1)
[0009]
[Problems to be solved by the invention]
The current interruption structure provided in the sealing plate according to the above prior art is effective for application to a relatively small lithium ion secondary battery, but has a high capacity and a high output as intended by the present invention. It cannot be said that it is suitable for application to secondary batteries. That is, the current path is the disk holder 64, the current cutoff valve 65, the explosion-proof valve 66, the PTC element 67, and the cap 68, and a contact resistance and a long current path are formed between them. There are problems that arise.
[0010]
Further, in order to apply such a structure of the sealing plate 62 to a high-capacity, high-power battery, there is a problem of sealing performance, and since there are many components, there are problems in that the number of assembling steps is large and the cost is high.
[0011]
In addition to the above-mentioned electrical factors such as overcharge, the cause of the battery going into an abnormal state is a mechanical or thermal factor. In a battery with a high energy density such as a lithium ion secondary battery, It is necessary to ensure the safety associated with them. In particular, it is an important issue in constructing a high capacity, high output battery. The electrical factors are the overcharge, external short circuit, and internal short circuit described above, and the thermal factor is the case when exposed to a high temperature environment, and the battery temperature rises. Since the internal pressure of the battery rises even if it is not in a state of being present, when the internal pressure rise rises to the limit, the current interrupting mechanism operates to stop the use of the secondary battery that has been exposed to high temperature and whose function has been reduced. In addition, as the internal pressure further increases, the explosion-proof valve operates to release the abnormal internal pressure to the outside and prevent the battery from bursting. Further, the mechanical factor is damage to the secondary battery due to crushing or the like, and suppresses occurrence of a failure when external pressure is applied. This can be solved by increasing the strength of the outer case, but the battery weight increases. Therefore, it is necessary to make the structure difficult to be crushed even by an external pressure and to prevent a failure from being caused by slight deformation.
[0012]
An object of the present invention is to provide a secondary battery provided with a current interrupting structure suitable for a high-capacity, high-power secondary battery having a reliable current interrupting function with a simple structure.
[0013]
[Means for Solving the Problems]
In order to achieve the above object, a secondary battery according to the present invention includes a positive electrode plate and a negative electrode plate that are wound in a cylindrical shape via a separator to form an electrode plate group, and a positive electrode plate at one end of the electrode plate group. Alternatively, one current collector plate connected to either one of the negative electrode plates and having a projecting portion at the center and having substantially the same diameter as the electrode plate group is disposed, and the one current collector plate is disposed at the other end of the electrode plate group. The other current collector plate that is connected to either the positive electrode plate or the negative electrode plate that is not connected and provided with an electrode terminal in the center is disposed, and a central opening that penetrates the protruding portion is formed in the one current collector plate. An electrode plate group is accommodated in an outer case formed in a bottomed cylindrical shape with an insulating spacer disposed so that one current collector plate is positioned on the bottom side, and the bottom of the outer case and one current collector plate between the projecting portion is welded at a predetermined welding strength, the electrolytic solution is impregnated into the electrode plate group, the outer casing Open end Ri Na is sealed by the sealing member by externally expose the electrode terminals, the bottom of the outer case with increase in the internal pressure of the battery, when the bulge exceeds a predetermined welding strength occurs, the bottom portion and the projecting portion It is characterized in that the battery current circuit is cut off by breaking the welded joint between and.
[0014]
According to the above configuration, when the battery internal pressure rises for some reason, the bottom of the outer case that is most likely to be deformed by the internal pressure rises outward. Since the bottom of the outer case is welded to the protruding part of the one current collector plate that penetrates the central opening of the spacer, the swelling of the bottom of the outer case is restrained by the one current collector plate via the spacer, but the welding strength On the other hand, when a bulge exceeding the width is generated, the weld between the protruding portion of the current collector plate and the outer case is broken. Since the outer case is connected to one current collector plate by welding to constitute one electrode of the battery, the current circuit of the secondary battery is cut off because the connection is broken due to breakage of the welded part. Therefore, since the current circuit is interrupted when the pressure in the outer case is abnormally increased due to an electrical cause such as overcharge, a high capacity, high output secondary battery can be configured with a simple structure.
[0015]
The spacer in the above configuration is preferably composed of anodized aluminum, a heat-resistant and electrolyte-resistant resin, a metal coated with a heat-resistant and electrolyte-resistant resin, or ceramic. Thus, when the bottom of the outer case is swollen, it is possible to obtain the strength to suppress the movement of the one current collecting plate following the bulge, and at the same time, the protrusion between the bottom of the outer case and the one current collecting plate. It is possible to configure so that the other parts are in an insulated state only by the welding part.
[0016]
The sealing member is provided with an opening for penetrating the electrode terminal and an explosion-proof means for releasing the abnormal internal pressure in the outer case to the outside, a lid plate fixed to the opening end of the outer case at the peripheral edge, and the lid High capacity by providing a sealing means for sealing between the electrode terminals, an insulating means for insulating between the lid and the electrode terminals, and a fixing means for fixing the electrode terminals to the lid. The opening end of the outer case containing the high-power generation element can be reliably sealed, and when the pressure inside the outer case rises abnormally, the abnormal internal pressure is released from the explosion-proof means to prevent the outer case from bursting. can do.
[0017]
In addition, by providing an insulating coating material that insulates the peripheral surface of the electrode plate group, insulation between the electrode plate group and the outer case can be ensured to prevent internal short circuit.
[0018]
In addition, by forming a cylindrical body in a cylindrical space formed at the center of the electrode plate group, the electrode plate group is deformed toward the cylindrical space when external pressure is applied to the outer case or due to internal pressure. It can be prevented from occurring.
[0019]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings to provide an understanding of the present invention. The present embodiment is an example embodying the present invention, and does not limit the technical scope of the present invention.
[0020]
FIG. 1 shows a configuration of a secondary battery 1 according to the present embodiment, which is configured as a lithium ion secondary battery. In the outer case 2 formed in a bottomed cylindrical shape, the electrode plate group 3 is accommodated together with the electrolyte, and on the bottom 2b side of the outer case 2, a positive electrode collector connected to the positive electrode plate constituting the electrode plate group 3 is accommodated. A protruding portion 14 a provided on the electric plate (one current collecting plate) 14 is welded, and a spacer 4 is interposed between the positive electrode current collecting plate 14 and the bottom of the outer case 2. Further, a negative electrode current collector plate (the other current collector plate) 5 is disposed on the other surface of the electrode plate group 3 so as to be connected to a negative electrode plate constituting the electrode plate group 3, and the negative electrode current collector plate 5 has a negative electrode terminal ( Electrode terminal) 11 is joined. The opening end of the outer case 2 exposes the negative electrode terminal 11 to the outside, and a cover plate 6, an O-ring (sealing means) 7, an insulating ring (insulating means) 8, and an insulating plate (insulating means) 9 A sealing member 20 made of is used to insulate and seal the cover plate 6 and the negative electrode terminal 11, and an insulating sealing state is fixed by a push nut (fixing means) 10. The flange portion 2a is caulked and fixed. With this configuration, the secondary battery 1 is configured with the outer case 2 as a positive electrode and the negative terminal 11 as a negative electrode.
[0021]
The electrode plate group 3 is formed in a cylindrical shape by winding a positive electrode plate and a negative electrode plate through a separator. Here, the positive electrode plate is obtained by applying a positive electrode mixture containing lithium cobalt oxide as a positive electrode active material and polyvinylidene fluoride as a binder on both surfaces of a positive electrode core material formed of an aluminum foil. Is formed. When the positive electrode mixture is applied to the positive electrode core material, the positive electrode mixture is not applied to the end side to which the positive electrode current collector plate 14 is joined, and the positive electrode core material is exposed to the end side. To do. The negative electrode plate is formed by applying a negative electrode mixture containing graphite as a negative electrode active material and polyvinylidene fluoride as a binder on both surfaces of a negative electrode core made of copper foil. When the negative electrode mixture is applied to the negative electrode core material, the negative electrode mixture is not applied to the end side to which the negative electrode current collector plate 5 is joined, and the negative electrode core material is exposed at the end side. To do.
[0022]
When the electrode plate group 3 configured as described above is accommodated in the outer case 2, the positive electrode current collector plate 14 is joined to one end face located on the bottom 2 b side of the outer case 2. As shown in FIG. 2, the positive electrode current collector plate 14 is formed with a protruding portion 14a protruding toward the bottom portion 2b on the surface of the outer casing 2 on the bottom 2b side at the center of the disc. A welded portion 14b protruding to the group 3 side is formed. As described above, since the positive electrode core material is exposed at one end of the positive electrode plate, when it is wound and formed in the electrode plate group 3, the positive electrode plate is spirally formed on one end surface of the electrode plate group 3. The core material is exposed. The positive collector plate 14 is pressed against the positive electrode plate of the electrode plate group 3 by pressing the welded portion 14b against the exposed positive electrode core material and welding the positive electrode core material and the welded portion 14b at a plurality of locations. Is connected in a state where there is little.
[0023]
Further, when the electrode plate group 3 is accommodated in the outer case 2, the negative electrode current collector plate 5 is joined to the other end surface located on the opening end side of the outer case 2. As shown in FIG. 3, the negative electrode current collector plate 5 is formed with a welded portion 5 a that protrudes in the diametrical direction toward the electrode plate group 3, and has two raised portions on the surface side facing the outside of the secondary battery 1. Part 5b is formed. As described above, since the negative electrode core material is exposed at the other end of the negative electrode plate, when it is wound and formed in the electrode plate group 3, the other end surface of the electrode plate group 3 is spirally formed on the other end surface. The core material is exposed. The negative electrode current collector plate 5 is pressed against the negative electrode plate of the electrode plate group 3 by pressing the welded part 5a against the exposed negative electrode core material and welding the negative electrode core material and the welded part 5a at a plurality of locations. Is connected in a state where there is little. A flange 11a formed on the negative electrode terminal 11 is fitted under the cut and raised portion 5b, and the gap between the cut and raised portion 5b and the flange 11a is welded to the negative electrode current collector plate 5. At the same time as the negative electrode terminal 11 is fixed, electrical connection is made.
[0024]
Further, the outer case 2 is formed by forming an aluminum plate into a bottomed cylindrical shape by deep drawing and, as shown in FIGS. 4 and 5, a flange portion 2 a that opens outward is formed at the opening end. When the electrode plate group 3 in which the positive electrode current collector plate 14 and the negative electrode current collector plate 5 are joined is inserted into the outer case 2, the spacer 4 is disposed on the bottom 2 b side of the outer case 2.
[0025]
As shown in FIG. 2, the spacer 4 has an opening 4a through which a protrusion 14a formed on the positive electrode current collector plate 14 passes, and the thickness of the spacer 4 is the height of the protrusion 14a. It is formed in the same way. The spacer 4 is insulative, heat resistance, and electrolyte resistance are required. Here, anodized aluminum is used, but the resin-coated metal or the whole is formed of resin or ceramic. You can also use what you did.
[0026]
As described above, when the spacer 4 is disposed on the bottom 2b of the outer case 2 and the electrode plate group 3 in which the positive electrode current collector plate 14 and the negative electrode current collector plate 5 are joined is inserted, the protruding portion 14a of the positive electrode current collector plate 14 is inserted. Passes through the opening 4 a of the spacer 4 and the top abuts against the bottom 2 b of the outer case 2. Laser welding is performed between the abutting protrusion 14a and the bottom 2b of the outer case 2 by laser light emitted from the outside of the bottom 2b. For this welding, electron beam welding can also be applied. An electrolyte solution is injected into the outer case 2 in which the electrode plate group 3 is accommodated, and the electrode plate group 3 is impregnated with the electrolyte solution.
[0027]
The electrolyte is a lithium salt such as lithium hexafluorophosphate (LiPF ₆ ) or lithium borofluoride (LiBF ₄ ) as a solute, ethylene carbonate (EC), propylene carbonate (PC), vinylene carbonate (VC), gamma butyrolactone. (GBL), dimethyl carbonate (DMC), diethyl carbonate (DEC), ethyl methyl carbonate (EMC) and other non-aqueous solvents.
[0028]
As shown in FIG. 4, the opening of the outer case 2 that accommodates the electrode plate group 3 impregnated with the electrolytic solution is sealed by a sealing member 20. In order to insulate and seal the outer case 2 from the negative electrode terminal 11, as shown in FIG. 5, after the O-ring 7 is arranged on the step of the negative electrode terminal 11 and the insulating ring 8 is arranged, the above-described opening is placed on the opening. The lid plate 6 is disposed so as to compress the O-ring 7, the insulating plate 9 is disposed thereon, and finally the push nut 10 is crimped to the negative electrode terminal 11. With this sealing structure, the negative electrode terminal 11 is insulated from the cover plate 6 by the cover plate 6, the insulating ring 8 and the insulating plate 9, and the sealed state with the negative electrode terminal 11 exposed to the outside from the exterior case 2 is the O-ring 7. Maintained by
[0029]
6 (a) and 6 (b), the cover plate 6 seals the opening of the outer case 2 by caulking the thin portion 6a formed around the cover plate 6 into the flange portion 2a of the outer case 2. To do. First, as shown in FIG. 6A, primary caulking is performed to bend the thin portion 6a of the cover plate 6 so as to wrap the flange portion 2a. Next, as shown in FIG. 6 (b), the opening of the outer case 2 is sealed by secondary caulking that bends the thin portion 6a enclosing the flange portion 2a and the flange portion 2a together. At this time, by applying a sealing agent to the peripheral surface of the thin-walled portion 6a, a fine gap is also sealed, so that complete sealing is achieved.
[0030]
As shown in FIG. 4, the cover plate 6 is provided with an explosion-proof valve 12, and when the pressure in the sealed outer case 2 abnormally rises, the internal pressure rises even after the current interrupting mechanism described later is activated. In this case, the explosion-proof valve 12 is opened so that the abnormally increased internal pressure can be released to the outside.
[0031]
When the charging / discharging circuit or control circuit to which the secondary battery 1 having the above configuration is connected is in a state where it is exposed to overcharge or the like, the positive and negative electrode active materials, the electrolyte solution, Reaction, decomposition of the electrolytic solution, and the like occur, and the pressure in the outer case 2 abnormally increases due to the generation of gas. Since the outer case 2 has a cylindrical shape, deformation mainly occurs at the bottom 2b when the internal pressure increases.
[0032]
As shown in FIG. 7A, the bottom 2b is a flat surface in a normal state, but bulges occur when the internal pressure of the outer case 2 rises abnormally. Since the bottom 2b of the outer case 2 is welded to the protruding portion 14a of the positive electrode current collector plate 14 at the center, the swelling due to the increase in internal pressure is centered on the welding point A as shown in FIG. It becomes a ring-shaped bulge. At this time, since the spacer 4 is disposed between the positive current collector 14 and the bottom 2b, the positive current collector 14 can be prevented from moving following the outward bulge of the bottom 2b. A ring-shaped bulge as shown in FIG. When the pressure in the outer case 2 further increases, the height of the ring-shaped bulge increases, and the movement of the positive electrode current collector plate 14 is suppressed by the spacer 4, so that the gap between the bottom 2b and the protrusion 14a at the welding point A is reduced. A force in the direction of breaking the weld acts on the steel. When the bulge of the bottom 2b exceeds the welding strength of the welding point A, as shown in FIG. 7C, the welding point A breaks and the bottom 2b becomes an arcuate bulge.
[0033]
Since the joint between the projecting portion 14a and the bottom portion 4b is broken at the welding point A, the electrical connection between the exterior case 2 serving as the positive electrode terminal and the positive electrode current collector plate 14 is interrupted. 1 is released from an overcharged state. As a result, the overcharge of the secondary battery 1 is stopped. However, when the internal pressure rises to the limit state when the internal pressure rises due to the rise of the battery temperature due to external heating or the state where the rise of the internal pressure does not stop, Since the explosion-proof valve 12 provided on the plate 6 is opened and the abnormal internal pressure is released to the outside, the secondary battery 1 is prevented from being ruptured.
[0034]
The cause of the battery's abnormal state is not only electrical factors such as overcharging as described above, but also mechanical or thermal factors. For batteries with high energy density, such as lithium ion secondary batteries, It is necessary to ensure the accompanying safety. In particular, it is an important issue in constructing a high capacity, high output battery. In the secondary battery 1 according to the present embodiment, when the outer peripheral surface of the electrode plate group 3 is covered with an insulating material such as a heat-shrinkable tube, the electrode plate group 3 is deformed by the external pressure applied to the outer case 2. The negative electrode plate of the electrode plate group 3 can be prevented from coming into contact with the outer case 2 and causing an internal short circuit. Further, when the positive electrode plate and the negative electrode plate are wound into a cylindrical shape via a separator, the cylindrical space generated in the center portion becomes a space in which the electrode plate group 3 is easily deformed by external pressure. It is preferable to insert an insulating cylindrical member into the cylindrical space to prevent the electrode group 3 from being deformed. You may comprise the said cylindrical member as a core which winds a positive electrode plate and a negative electrode plate through a separator.
[0035]
In the configuration described above, the outer case 2 is made of aluminum to reduce the weight, but it can also be formed by deep drawing a nickel plated plate or a stainless plate. In this case, the negative electrode plate constituting the electrode plate group 3 is connected to the outer case 2, the outer case 2 is used as the negative electrode, and the positive electrode plate constituting the electrode plate group is connected to the electrode terminal serving as the negative electrode terminal 11. The terminal 11 is changed to a positive terminal.
[0036]
Moreover, although this embodiment showed the example comprised to the lithium ion secondary battery, even if it applies the same structure to secondary batteries and primary batteries, such as a nickel-hydrogen storage battery, it will become effective.
[0037]
【The invention's effect】
As described above, according to the present invention, it is possible to configure a secondary battery having a current interrupting function that interrupts a current circuit when the internal pressure of the battery is abnormally increased with a simple configuration, and the internal resistance increases to provide the current interrupting function. Therefore, there is an effect that is suitable for constructing a high-capacity, high-power secondary battery that constitutes a power battery power source such as an automobile power source.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing a configuration of a secondary battery according to an embodiment.
FIG. 2 is a perspective view showing a configuration of a positive electrode current collector plate and a spacer.
FIG. 3 is a perspective view illustrating a configuration of a negative electrode current collector plate and a negative electrode terminal.
FIG. 4 is a perspective view showing a configuration of a sealing member.
FIG. 5 is a partial cross-sectional view showing a sealing structure that seals an opening of an exterior case.
FIG. 6 is a partial cross-sectional view showing a caulking structure between an outer case and a cover plate.
FIG. 7 is a cross-sectional view showing the operation of the current interrupting function step by step.
FIG. 8 is a cross-sectional view showing a configuration of a current interrupt mechanism according to the prior art.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Secondary battery 2 Exterior case 3 Electrode plate group 4 Spacer 5 Negative electrode current collector plate (the other current collector plate)
6 Lid 7 O-ring (sealing means)
8 Insulation ring (insulation means)
9 Insulation plate (insulation means)
10 Push nut (fixing means)
11 Negative terminal (electrode terminal)
14 Positive current collector (one current collector)
20 Sealing member

Claims (8)

A positive electrode plate and a negative electrode plate are wound into a cylindrical shape through a separator to form an electrode plate group,
One current collector plate is disposed at one end of the electrode plate group and connected to either the positive electrode plate or the negative electrode plate, and has a projecting portion at the center with the same diameter as the electrode plate group,
The other current collector plate provided with an electrode terminal in the center connected to either the positive electrode plate or the negative electrode plate to which the one current collector plate is not connected to the other end of the electrode plate group is disposed,
To position one collector plate on its bottom side into the exterior case formed in said one current collector plate to the protrusions by arranging a spacer of insulating the central opening formed to penetrate a bottomed cylindrical shape The electrode plate group is accommodated as
A gap between the bottom of the outer case and the protruding portion of the current collector plate is welded with a predetermined welding strength , the electrode plate group is impregnated with an electrolytic solution, and the open end of the outer case exposes the electrode terminal to the sealing Ri Na is sealed by members,
When the bulge exceeding the predetermined welding strength occurs at the bottom of the outer case due to the rise of the battery internal pressure, the weld joint between the bottom and the protrusion is broken and the battery current circuit is cut off. A secondary battery characterized by being configured .   The secondary battery according to claim 1, wherein the spacer is made of anodized aluminum.   The secondary battery according to claim 1, wherein the spacer is formed of a heat-resistant and electrolyte-resistant resin.   The secondary battery according to claim 1, wherein the spacer is formed by coating a metal with a heat-resistant and electrolyte-resistant resin.   The secondary battery according to claim 1, wherein the spacer is made of ceramic.   The sealing member is provided with an opening for penetrating the electrode terminal and an explosion-proof means for releasing the abnormal internal pressure in the outer case to the outside, a lid plate fixed to the opening end of the outer case at the peripheral edge, and the lid and the electrode terminal 2. The device according to claim 1, further comprising: a sealing unit that seals between the two, an insulating unit that insulates between the lid and the electrode terminal, and a fixing unit that fixes the electrode terminal to the lid. Next battery. The secondary battery according to claim 1, further comprising an insulating coating material for insulatingly coating a peripheral surface of the electrode plate group.   The secondary battery according to claim 1, wherein a cylindrical body is fitted into a cylindrical space formed at the center of the electrode plate group.

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