Electricity storage device

Abstract

This electricity storage device is provided with: an electrode body in which a positive electrode plate and a negative electrode plate are wound with a separator interposed therebetween; and a positive electrode collector plate that is disposed at the upper end of the electrode body in the axial direction (P) and that is joined to the positive electrode plate, the positive electrode collector plate having: a plate-shaped flange section that is joined to the positive electrode plate on a surface facing the positive electrode plate in the axial direction (P); and a column part protruding from the flange part toward the upper side in the axial direction (P) and capable of adjusting the length in the axial direction (P).

Description

Technical Field

[0001] The present invention relates to an electric storage device. Background Art

[0002] A cylindrical battery, one of the power storage devices, has an electrode body formed by winding a positive electrode plate and a negative electrode plate with a separator interposed therebetween. In addition, a large-diameter cylindrical battery sometimes has a structure in which a positive electrode collector plate is joined to an exposed portion of a positive electrode core material protruding from the electrode body (hereinafter referred to as an end face collector structure) (e.g., Patent Document 1).

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Application Publication No. 2005-203374 Summary of the invention

[0006] In the above-mentioned end face current collection structure, a certain high output can be expected. However, the end face current collection structure needs to further improve performance.

[0007] Therefore, an object of the present invention is to provide a high-output power storage device.

[0008] The present invention provides an energy storage device, which comprises: an electrode body, which is formed by winding a first electrode plate and a second electrode plate with a separator in between; and a collector plate, which is arranged at one axial end of the electrode body and is joined to the first electrode plate, and is characterized in that the collector plate has: a plate-shaped flange portion, the surface of the flange portion facing the first electrode plate in the axial direction is joined to the first electrode plate; and a column portion, which protrudes from the flange portion toward one side in the axial direction and can adjust the axial length.

[0009] According to the power storage device of the present invention, a high-output power storage device can be realized. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 It is a cross-sectional view showing a power storage device as an example of an embodiment.

[0011] Figure 2 It is a perspective view showing a positive electrode current collecting plate before being assembled in a power storage device as an example of an embodiment.

[0012] Figure 3 It is a perspective view showing a positive electrode current collecting plate assembled in a power storage device as an example of the embodiment.

[0013] Figure 4 yes Figure 2 Cross-sectional view in the AA direction.

[0014] Figure 5It is a perspective view showing a positive electrode current collector plate as another example of the embodiment.

[0015] Figure 6 It is a perspective view showing a positive electrode current collector plate as another example of the embodiment.

[0016] Figure 7 This is a flowchart showing the flow of a manufacturing process of a power storage device as an example of the embodiment.

[0017] Figure 8 It is a cross-sectional view showing a power storage device as another example of the embodiment. DETAILED DESCRIPTION

[0018] In the following description, specific shapes, materials, directions, numerical values, etc. are illustrative for easy understanding of the present invention and can be appropriately changed according to the application, purpose, specification, etc.

[0019] <Electricity storage device>

[0020] use Figure 1 An electric storage device 10 as an example of an embodiment will be described. The present invention is not limited to the electric storage device 10 , and may be a capacitor or the like including an electrode body 14 in which a positive electrode plate 11 and a negative electrode plate 12 are wound with a separator 13 interposed therebetween.

[0021] The power storage device 10 includes an electrode body 14 formed by winding a strip-shaped positive electrode plate 11 as a strip-shaped first electrode plate and a negative electrode plate 12 as a second electrode plate via a strip-shaped separator 13. The power storage device 10 can achieve high output, which will be described in detail later.

[0022] In addition, the power storage device 10 includes the above-mentioned electrode body 14, an electrolyte (not shown), an outer can 30 for storing the electrode body 14 and the electrolyte, and a sealing body 35 for sealing the opening of the outer can 30. Hereinafter, each component will be described according to the axial direction P, radial direction D, and circumferential direction R of the power storage device 10 (electrode body 14). In addition, in the axial direction P, the side where the sealing body 35 described later is provided is sometimes set as the upper side, and the bottom 30B side of the outer can 30 is set as the lower side for description.

[0023] The positive electrode plate 11 has a strip-shaped positive electrode core material and a positive electrode mixture layer formed on at least one surface of the positive electrode core material. For the positive electrode core material, a foil of a metal such as aluminum or aluminum alloy that is stable within the potential range of the positive electrode, a film that arranges the metal on the surface, etc. can be used. The positive electrode mixture layer includes a positive electrode active material, a conductive agent such as acetylene black, and a binder such as polyvinylidene fluoride. As an example, the positive electrode mixture layer is formed on both surfaces of the positive electrode core material. For the positive electrode active material, for example, a lithium transition metal composite oxide is used.

[0024] On the upper end side of the positive electrode plate 11 (one end side in the width direction of the positive electrode plate 11), there is a protruding positive electrode core material exposed portion 15 where no positive electrode mixture layer is provided on the positive electrode core material. On the upper side of the electrode body 14, there are provided a positive electrode collector plate 20 described in detail later and an upper insulating plate 18 arranged on the upper side of the positive electrode collector plate 20. The positive electrode collector plate 20 is joined to the positive electrode core material exposed portion 15 of the positive electrode plate 11. Thus, the positive electrode plate 11 is electrically connected to the positive electrode collector plate 20. In addition, the positive electrode collector plate 20 is joined to the bottom surface of the central portion of the cover 36, so that the positive electrode collector plate 20 and the cover 36 are electrically connected. Through this connection, the cover 36 functions as a positive external terminal. The upper insulating plate 18 prevents the positive electrode plate 11 from contacting the outer can 30.

[0025] The negative electrode plate 12 has a strip-shaped negative electrode core material and a negative electrode mixture layer formed on at least one surface of the negative electrode core material. For the negative electrode core material, foils of metals such as copper, copper alloy, nickel, nickel alloy, etc. that are stable within the potential range of the negative electrode, and films that arrange the metal on the surface layer, etc. can be used. The negative electrode mixture layer contains a negative electrode active material and a binder such as styrene-butadiene rubber (SBR). As an example, the negative electrode mixture layer is formed on both surfaces of the negative electrode core material. For the negative electrode active material, for example, graphite, silicon-containing compounds, etc. are used.

[0026] At the lower end side of the negative electrode plate 12 (one end side in the width direction of the negative electrode plate 12), a negative electrode core material exposed portion 16 where no negative electrode mixture layer is provided on the negative electrode core material is protruded. A negative electrode collector plate 17 is provided at the lower side of the electrode body 14, and the negative electrode core material exposed portion 16 is joined to the negative electrode collector plate 17. Thus, the negative electrode plate 12 and the negative electrode collector plate 17 are electrically connected. In addition, the negative electrode collector plate 17 is joined to the inner surface of the bottom 30B of the outer can 30, so that the negative electrode collector plate 17 and the outer can 30 are electrically connected. Through this connection, the outer can 30 functions as a negative electrode external terminal.

[0027] The electrolyte is a non-aqueous electrolyte, comprising a non-aqueous solvent and an electrolyte salt dissolved in the non-aqueous solvent. For the non-aqueous solvent, for example, esters, ethers, nitriles, amides, and mixed solvents of two or more thereof are used. The non-aqueous solvent may contain a halogen substituted substance formed by replacing at least a portion of the hydrogen of these solvents with a halogen atom such as fluorine. As an example of a non-aqueous solvent, ethylene carbonate (EC), ethyl methyl carbonate (EMC), dimethyl carbonate (DMC), and mixed solvents thereof, etc. can be cited. For the electrolyte salt, for example, a lithium salt such as LiPF is used.

[0028] The outer can 30 is a metal container with a bottom and a cylindrical shape with an opening on the upper end side, and has a cylindrical portion 30A formed in a cylindrical shape and a bottom 30B that is circular when viewed from above. The outer can 30 is usually made of a metal with iron as a main component. However, in particular, when the outer can 30 is electrically connected to the positive electrode plate 11, the outer can 30 may also be made of a metal with aluminum or the like as a main component. In the case where the outer can 30 is made of iron as a main component, a plating layer of nickel or the like may also be formed on the surface made of the iron. In addition, the cylindrical portion 30A of the outer can 30 has a groove 30C formed along the circumferential direction R of the cylindrical portion 30A. The groove 30C is formed near the opening of the outer can 30 and at a position of a predetermined length from the edge of the opening (the upper end of the outer can 30). The predetermined length is, for example, a length equivalent to 1% to 20% of the length of the axial direction P of the outer can 30.

[0029] In the present embodiment, a safety valve mechanism that operates when an abnormality occurs in the power storage device 10 is provided at the bottom 30B of the outer tank 30. On the other hand, no safety valve mechanism is provided at the sealing body 35. A groove-shaped thin-walled portion is formed at the bottom 30B, for example. When an abnormality occurs in the power storage device 10 and the internal pressure rises, when the bottom 30B is pushed out of the outer tank 30, the thin-walled portion is preferentially broken to form a gas discharge port at the bottom 30B.

[0030] The groove 30C is a portion of the barrel 30A that extends toward the inside of the outer can 30. For example, the barrel 30A is spun from the outside to form the groove 30C. In addition, the outer can 30 is reduced in diameter at the position where the groove 30C is formed, and a thin line-shaped groove 30C is formed on the outer peripheral surface of the barrel 30A. The cross section of the groove 30C has a substantially U-shaped shape, and is formed in an annular shape over the entire length of the circumferential direction R of the barrel 30A. The groove 30C is formed by processing the barrel 30A after the electrode body 14 is housed in the outer can 30.

[0031] The sealing body 35 has a cover 36 and a gasket 38, and is formed in a disc shape as a whole. The sealing body 35 is arranged on the groove 30C of the outer can 30 and is fixed to the opening of the outer can 30. The upper end of the opening is bent inward and is clamped relative to the sealing body 35 through the gasket 38. In other words, the sealing body 35 is fixed to the upper end of the outer can 30 through the groove 30C of the outer can 30 and the clamping part, and the opening of the outer can 30 is blocked. The clamping part is formed in an annular shape along the circumferential direction R of the outer can 30, and clamps the sealing body 35 together with the groove 30C.

[0032] The cover 36 is a disc-shaped metal member, which is exposed to the outside of the outer can 30 and forms the top surface of the power storage device 10. The cover 36 has a shape (raised portion) in which the central portion of the radial direction D protrudes to the outside of the power storage device 10. When a plurality of power storage devices 10 are modularized to form a battery pack, a wiring material is connected to the cover 36. Therefore, the cover 36 functions as an external terminal of the power storage device 10. In the present embodiment, the positive electrode collector plate 20 is electrically connected to the cover 36, and the cover 36 functions as a positive electrode external terminal.

[0033] The gasket 38 is provided on the outer periphery of the cap 36 . The gasket 38 is an annular resin member or rubber member for preventing the cap 36 from contacting the outer can 30 and ensuring insulation between the outer can 30 and the sealing body 35 .

[0034] <Positive electrode collector plate>

[0035] use Figure 2 to Figure 4 The positive electrode current collector plate 20 as an example of the embodiment will be described.

[0036] As described above, the positive electrode collector plate 20 is joined to the positive electrode core material of the positive electrode plate 11 and to the bottom surface of the central portion of the cover 36, so that the cover 36 functions as a positive electrode external terminal. In addition, the length of the axial direction P of the positive electrode collector plate 20 can be adjusted. Thus, the resistance of the positive electrode collector plate 20 can be reduced. As a result, the output of the power storage device 10 can be increased.

[0037] like Figure 2 As shown, the positive electrode collector plate 20 has: a flange portion 21, the surface of the flange portion 21 facing the positive electrode plate 11 (electrode body 14) in the axial direction P is joined to the positive electrode core material exposed portion 15 of the positive electrode plate 11; and a column portion 23, which protrudes from the flange portion 21 toward the upper side (cover 36 side) in the axial direction P, and can adjust the length in the axial direction P. In addition, Figure 2 The example shown is the positive electrode collector plate 20 before being assembled in the power storage device 10. After the positive electrode collector plate 20 is assembled in the power storage device 10, as shown in FIG. Figure 3 As in the illustrated example, the length of the column portion 23 in the axial direction P is shortened to the length of the gap between the electrode body 14 and the lid 36 .

[0038] The flange portion 21 is formed, for example, in a disc shape having substantially the same diameter as the electrode body 14 when viewed from the axial direction P. A plurality of joining grooves 22 as the second grooves are formed in the flange portion 21 along the radial direction D. The joining grooves 22 are joined to the exposed portion 15 of the positive electrode core material exposed from the positive electrode plate 11. The joining grooves 22 are formed in a substantially V-shape or a substantially U-shape protruding toward the electrode body 14 when viewed from the radial direction D. The plurality of joining grooves 22 are arranged at intervals in the circumferential direction R. Figure 2In the example shown, four engagement grooves 22 are arranged radially from the column 23 at intervals of 90 degrees. In addition, in the present embodiment, the engagement grooves 22 are configured to extend in four directions, but may also be configured to extend in one direction, two directions, three directions, or five directions or more. In addition, the flange portion 21 used in the power storage device 10 of the present invention may not necessarily be disc-shaped. It may also be a rectangular plate.

[0039] The column portion 23 is provided at the center portion of the flange portion 21 when viewed from the axial direction P, and is formed into a cylindrical shape extending along the axial direction P. In addition, the column portion 23 may also be a square column. The column portion 23 has a top portion 24 and a barrel portion 25, which are described in detail later. The top portion 24 abuts against the bottom surface of the center portion of the cover 36 after the positive electrode collector plate 20 is assembled to the power storage device 10, and is joined to the bottom surface of the center portion of the cover 36 by welding. The top portion 24 blocks one end of the barrel portion 25 in the axial direction P.

[0040] A plurality of slits 26 are formed on the lateral surface of the barrel 25. The slits 26 extend along the axial direction P. The slits 26 may extend from near the upper end to near the lower end of the barrel 25 in the axial direction P. The number of slits 26 is not particularly limited. Here, the portion of the barrel 25 located between adjacent slits 26 is provided as a side wall 27. The width of the side wall 27 may be greater than the width of the slit 26. Alternatively, the barrel 25 may be connected to the flange portion 21 on the outer circumferential surface of the other end in the axial direction P, and an opening may be formed at the other end. With this structure, the column 23 can be deformed more smoothly. In addition, by making the barrel 25 hollow, when the side wall 27 described later is bent inward in the radial direction D, the bent side wall 27 can also be accommodated in the barrel 25.

[0041] With the above structure, when the positive electrode collector plate 20 is assembled to the power storage device 10 (in the pressing step S13 described in detail later), the side wall 27 is bent outward in the radial direction D, thereby shortening the axial length P of the column portion 23 to the length of the gap between the electrode body 14 and the cover 36 .

[0042] According to the positive current collector plate 20, the positive electrode plate 11 and the cap 36 as the positive electrode external terminal are electrically connected only through the positive current collector plate 20, so that the resistance from the positive electrode plate 11 to the cap 36 can be reduced. Thus, the power storage device 10 can have a higher output.

[0043] The positive electrode current collector plate 20 can absorb variations in the gap between the electrode body 14 and the lid 36 of the power storage device 10 . In other words, the length of the column portion 23 in the axial direction P can be adjusted for each individual power storage device 10 .

[0044] The positive electrode collector plate 20 can be applied to power storage devices (for example, power storage device 50 described below) having different gaps between the electrode body 14 and the cover 36 of the power storage device 10. In other words, the versatility of the positive electrode collector plate 20 can be improved.

[0045] Furthermore, since no gap is generated between the positive collector plate 20 and the cover 36 after the positive collector plate 20 is assembled to the power storage device 10, welding defects between the positive collector plate 20 and the cover 36 can be reduced. The reliability of the power storage device 10 is improved.

[0046] Furthermore, according to the positive electrode collector plate 20 , since the positive electrode collector plate 20 is assembled without a gap between the electrode body 14 and the lid 36 , the positive electrode collector plate 20 is firmly fixed and held relative to the power storage device 10 in the axial direction P, and the vibration resistance and impact resistance of the power storage device 10 can be improved.

[0047] like Figure 4 As shown in the figure, an upper groove 27A as a first groove is formed on the outer circumferential surface of the upper end portion in the axial direction P of the side wall 27 (at the same position as the upper end portion in the axial direction P of the adjacent slit 26 in the axial direction P). In addition, a lower groove 27B as a first groove is formed on the outer circumferential surface of the lower end portion in the axial direction P of the side wall 27 (at the same position as the lower end portion in the axial direction P of the adjacent slit 26 in the axial direction P). Furthermore, a middle groove 27C as a first groove is formed on the inner circumferential surface of the central portion in the axial direction P of the side wall 27.

[0048] In addition, in the present embodiment, the upper groove 27A and the lower groove 27B are formed on the outer peripheral surface, but the present invention is not limited thereto. The upper groove 27A and the lower groove 27B may be formed on the inner peripheral surface. In addition, in the present embodiment, the middle groove 27C is formed on the inner peripheral surface, but the present invention is not limited thereto. The middle groove 27C may be formed on the outer peripheral surface.

[0049] By forming the upper groove 27A, the lower groove 27B and the middle groove 27C in the side wall 27, the side wall 27 is easily bent toward the outside in the radial direction D when the cover 36 is pressed when assembling the positive electrode current collector plate 20. In addition, in the current collector plate of the present invention, the side wall 27 can be easily bent toward the inside in the radial direction D by using the upper groove 27A and the lower groove 27B formed on the inner surface of the side wall 27 (cylindrical portion 25) and the middle groove 27C formed on the outer surface of the side wall 27 (cylindrical portion 25).

[0050] <Other embodiments (positive electrode current collector plate)>

[0051] use Figure 5 and Figure 6 A positive electrode current collector plate 20 as another example of the embodiment will be described.

[0052] Hereinafter, regarding the positive electrode current collector plate 20 as another example of the embodiment, only the positive electrode current collector plate 20 and the positive electrode current collector plate 20 will be described. Figure 2 to Figure 4 The positive electrode current collector plate 20 described in the above has a different structure, and the other structures are the same as those of the positive electrode current collector plate 20 described above, so the description is omitted.

[0053] like Figure 5 As shown, a plurality of slits 26 are formed in the barrel 25 of the column 23 of the positive electrode collector plate 20. The slits 26 are formed obliquely with respect to the axial direction P. The inclination angle of the slits 26 with respect to the axial direction P can be greater than 0° and less than 30°. With such slits 26, the length of the slits 26 per unit length of the axial direction P can be longer than the length of the slits 26 extending along the axial direction P. In addition, if the column 23 is cylindrical, the inclined plurality of slits 26 formed on the outer peripheral surface of the barrel 25 can be arranged in the circumferential direction R with the slits 26 of the same shape, and the deviation in the shape of the side wall 27 formed between a pair of slits 26 can also be suppressed. Compared with the case where the inclined slits 26 are formed on a plane, the deviation in the bending condition of each side wall 27 can be suppressed.

[0054] like Figure 6 As shown, the flange portion 21 of the positive electrode current collector plate 20 is formed with a notch 28. The notch 28 is formed in the flange portion 21 except for the joining groove 22. This facilitates the movement of the electrolyte in the outer can 30 and the movement of the gas generated by the decomposition of the electrolyte.

[0055] <Manufacturing process of power storage device>

[0056] use Figure 7 A process for manufacturing the power storage device 10 as an example of the embodiment will be described.

[0057] The manufacturing process of the power storage device 10 is a process for manufacturing the above-mentioned power storage device 10. Hereinafter, the process of assembling the positive electrode current collector plate 20 to the power storage device 10 will be described, and the description of other processes will be omitted. The manufacturing process of the power storage device 10 includes a first welding process S11, a liquid injection process S12, a pressing process S13, a caulking process S14, and a second welding process S15, which will be described in detail later.

[0058] In the first welding step S11, the positive electrode collector plate 20 is arranged at the upper end of the electrode body 14 in the axial direction P, and the positive electrode core material exposed portion 15 protruding from the electrode body 14 and the joint groove 22 of the flange portion 21 of the positive electrode collector plate 20 are joined by welding. At this time, the positive electrode core material exposed portion 15 protruding from the electrode body 14 can be welded in a state of being bent inward in the radial direction D. In the liquid injection step S12, the electrolyte is injected into the outer can 30 containing the electrode body 14 and the positive electrode collector plate 20.

[0059] In the pressing step S13, the cover 36 provided with the gasket 38 is pressed toward the positive electrode collector plate 20 so as to close the opening of the outer can 30. At this time, the column portion 23 of the positive electrode collector plate 20 is pressed and the side wall 27 is bent, thereby shortening the length of the column portion 23 in the axial direction P to the length of the gap between the electrode body 14 and the cover 36.

[0060] In the caulking step S14, the lid 36 and the gasket 38 are fixed to the opening of the outer can 30 by caulking the opening of the outer can 30. In the second welding step S15, the lid 36 and the top surface portion 24 of the column portion 23 of the positive electrode current collector plate 20 are joined by welding.

[0061] <Other embodiments (power storage device)>

[0062] use Figure 8 A power storage device 50 as another example of the embodiment will be described.

[0063] The power storage device 50 includes an electrode body 54 formed by winding a strip-shaped positive electrode plate 51 as a first electrode plate and a negative electrode plate 52 as a second electrode plate with a strip-shaped separator 53 interposed therebetween, an electrolyte (not shown), an outer can 55 for accommodating the electrode body 54 and the electrolyte, a rivet 56 as an external positive electrode terminal, and the above-mentioned positive electrode collector plate 20.

[0064] The rivet 56 is fixed to the opening formed on the upper end surface of the outer can 30 in the axial direction P via the insulating plate 57. The positive electrode collector plate 20 is joined to the bottom surface of the rivet 56 and the positive electrode plate 51, and the rivet 56 functions as a positive electrode external terminal. In addition, the joining between the bottom surface of the rivet 56 and the positive electrode collector plate 20 is achieved by inserting a welding tool from the through hole formed in the axial center of the electrode body 54 through the opening at the other end of the barrel 25, and making the welding tool abut against the lower surface of the top surface 24 to perform welding.

[0065] In addition, the present invention is not limited to the above-mentioned embodiment and its modified example, and various changes and improvements can be made within the scope of the matters described in the claims of the present application. It goes without saying that the collector plate having the flange portion 21 and the column portion 23 of the present invention is described as the positive electrode collector plate 20, but the collector plate of the present invention may also be the negative electrode collector plate 17. In addition, the column portion 23 of the collector plate of the present invention may also be joined to the outer can 30.

[0066] Description of Reference Numerals

[0067] 10, 50, power storage device; 11, 51, positive electrode plate; 12, 52, negative electrode plate; 13, 53, spacer; 14, 54, electrode body; 15, exposed portion of positive electrode core material; 16, exposed portion of negative electrode core material; 17, negative electrode collector plate; 18, upper insulating plate; 20, positive electrode collector plate; 21, flange portion; 22, joint groove (second groove); 23, column portion; 24, top portion; 25, barrel portion; 26, slit; 27, side wall; 27A, upper groove (first groove); 27B, lower groove (first groove); 27C, middle groove (first groove); 28, notch; 30, 55, outer can; 30A, barrel portion; 30B, bottom; 30C, groove; 35, sealing body; 36, cover; 38, gasket; 56, rivet; 57, insulating plate.

Claims

1. A power storage device comprising: an electrode body formed by winding a first electrode plate and a second electrode plate with a separator interposed therebetween; and a current collector plate disposed at one end of the electrode body in the axial direction and joined to the first electrode plate, wherein: The collector plate has: a plate-shaped flange portion, a surface of the flange portion facing the first electrode plate in the axial direction being joined to the first electrode plate; as well as The column portion protrudes from the flange portion toward one side in the axial direction and is capable of adjusting the length in the axial direction.

2. The power storage device according to claim 1, wherein The column portion includes a cylindrical tube portion and a top surface portion that blocks one axial end of the tube portion, and the column portion is connected to the flange portion at the other axial end side of the tube portion.

3. The power storage device according to claim 2, wherein: A plurality of slits are formed on the side circumference of the column portion. The slits are arranged along the circumferential direction of the side surface of the cylinder. When a portion of the side peripheral surface of the column portion remaining between the adjacent slits is used as a side wall, the length in the axial direction is adjusted by bending the side wall.

4. The power storage device according to claim 3, wherein: The slit extends in the axial direction.

5. The power storage device according to claim 3, wherein: The slit extends obliquely with respect to the axial direction.

6. The power storage device according to any one of claims 3 to 5, wherein: A first groove is formed in the side wall along the circumferential direction, The side wall is bent along the first groove.

7. The power storage device according to claim 6, wherein: The first grooves are formed at both end sides of the side wall in the axial direction.

8. The power storage device according to claim 6, wherein: The first groove is formed in a central portion of the side wall in the axial direction.

9. The power storage device according to any one of claims 2 to 8, wherein: The power storage device further includes an external terminal, and the top surface portion of the column portion is joined to the external terminal.

10. The power storage device according to any one of claims 2 to 7, wherein: The flange portion is provided with a second groove protruding toward the first electrode plate in a radial direction. The second groove is joined to the first electrode plate.

11. The power storage device according to any one of claims 2 to 10, wherein: The cylindrical portion of the column portion has an opening at the other end.

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