Power storage cell

Abstract

To further improve energy density.SOLUTION: In a power storage cell 1, a first electrode 11N of a wound electrode body 10 includes: a sheet-like collector 111N; and an electrode mixture layer 112N formed on the collector 111N. The collector 111N includes: a coated part 111NA which is coated with the electrode mixture layer 112N; and an uncoated part 111NB which is not coated with the electrode mixture layer 112N. The uncoated part 111NB protrudes from the coated part 111NA to one side in an axial direction Z of the wound electrode body 10. A case 20 houses the wound electrode body 10. The case 20 includes a cylindrical wall part 22 and a bottom part 23. The cylindrical wall part 22 is provided so as to cover an outer peripheral side of the wound electrode body 10. The bottom part 23 is disposed on one side in the axial direction Z and is connected to one end of the cylindrical wall part 22. The bottom part 23 is bonded to the uncoated part 111NB by welding from the outside of the case 20.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to an energy storage cell. [Background technology]

[0002] Patent Document 1 (JP Patent Publication 10-162854A) discloses a cylindrical battery with a spiral electrode group and a tabless-type current collection system. A roughly disk-shaped current collector is welded to the conductive edge of the negative electrode plate that protrudes outward from the upper and lower end faces of the electrode group. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 10-162854 Summary of the Invention [Problem to be solved by the invention]

[0004] In a power storage cell such as the cylindrical battery disclosed in Patent Document 1, there is room to further reduce the number of parts and further improve the energy density per unit volume of the cell.

[0005] The present disclosure has been made in consideration of the above problems, and has an object to provide an energy storage cell with further improved energy density. [Means for solving the problem]

[0006] The energy storage cell according to the present disclosure includes a wound electrode body and a case. The wound electrode body includes a wound first electrode and a wound second electrode. The first electrode includes a sheet-shaped current collector and an electrode mixture layer formed on the current collector. The current collector includes a coated portion coated with the electrode mixture layer and an uncoated portion not coated with the electrode mixture layer. The uncoated portion protrudes from the coated portion to one side in the axial direction of the wound electrode body. The case houses the wound electrode body. The case includes a cylindrical wall portion and a bottom portion. The cylindrical wall portion is provided so as to cover the outer periphery side of the wound electrode body. The bottom portion is disposed on one side in the axial direction and is connected to one end of the cylindrical wall portion. The bottom portion is joined to the uncoated portion by welding from the outside of the case.

[0007] According to the above configuration, the bottom of the case has a current collecting function for the first electrode. Therefore, a current collecting plate, which is a member different from the case, is not required for the first electrode, and the number of parts of the energy storage cell can be reduced. This increases the space in the case that can accommodate the wound electrode body, making it possible to accommodate a larger wound electrode body. As a result, the energy density of the energy storage cell is further improved. Effect of the Invention

[0008] According to the present disclosure, it is possible to provide a storage cell with further improved energy density. [Brief description of the drawings]

[0009] [Figure 1] 1 is a cross-sectional view showing a storage cell according to a first embodiment. [Diagram 2] FIG. 2 is a partially exploded perspective view of a wound electrode body. [Diagram 3] FIG. 1 is an exploded perspective view showing an electricity storage cell according to a first embodiment. [Figure 4] 4 is another exploded perspective view showing the energy storage cell according to the first embodiment. FIG. [Diagram 5] FIG. 6 is a cross-sectional view of a storage cell according to a second embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Hereinafter, a storage cell according to each embodiment of the present disclosure will be described with reference to the drawings. The same or corresponding parts in the drawings are denoted by the same reference characters, and description thereof will not be repeated.

[0011] (Embodiment 1) Fig. 1 is a cross-sectional view showing a storage cell according to embodiment 1. As shown in Fig. 1, the storage cell 1 according to embodiment 1 of the present disclosure includes a wound electrode body 10, a case 20, and a positive electrode current collector plate 30.

[0012] First, the wound electrode body 10 will be described. Fig. 2 is a perspective view showing a partially exploded wound electrode body. As shown in Fig. 1 and Fig. 2, the wound electrode body 10 is wound to have a cylindrical shape. Fig. 2 shows the wound electrode body 10 in a slightly unwound state.

[0013] The wound electrode body 10 includes a positive electrode 11P, a negative electrode 11N, and a separator 12. In the first embodiment, the negative electrode 11N is exemplified as the first electrode in the present disclosure, and the positive electrode 11P is exemplified as the second electrode. The first electrode may be a positive electrode, and the second electrode may be a negative electrode.

[0014] Positive electrode 11P and negative electrode 11N have a sheet-like outer shape. Wound electrode body 10 is composed of an electrode plate group in which positive electrode 11P and negative electrode 11N are wound with separator 12 interposed therebetween.

[0015] Separator 12 is provided between positive electrode 11P and negative electrode 11N. Separator 12 separates positive electrode 11P from negative electrode 11N while allowing ions (e.g., lithium ions) to move between positive electrode 11P (positive electrode active material) and negative electrode 11N (negative electrode active material).

[0016] Positive electrode 11P includes positive electrode current collector 111P and positive electrode mixture layer 112P. Positive electrode current collector 111P is made of, for example, aluminum.

[0017] The positive electrode mixture layer 112P is applied to both radial surfaces of the positive electrode current collector 111P (positive electrode coating portion 111PA described later). The positive electrode mixture layer 112P is in close contact with the separator 12. The positive electrode mixture layer 112P is formed by applying a positive electrode slurry to the surface of the positive electrode current collector 111P and drying it. The positive electrode slurry is a slurry prepared by kneading the materials of the positive electrode mixture layer 112P (such as a positive electrode active material and a binder) and a solvent. The thickness of the positive electrode mixture layer 112P is, for example, 0.1 μm or more and 1000 μm or less.

[0018] Positive electrode current collector 111P includes positive electrode coated portion 111PA and positive electrode uncoated portion 111PB. Positive electrode coated portion 111PA is a portion of positive electrode current collector 111P that is coated with positive electrode composite material layer 112P. In other words, positive electrode coated portion 111PA is a portion that is not exposed because it is covered with positive electrode composite material layer 112P.

[0019] The positive electrode uncoated portion 111PB is an exposed portion of the positive electrode current collector 111P that is not covered by the positive electrode composite layer 112P. The positive electrode uncoated portion 111PB is located on the first direction Z1 side along the axial direction Z relative to the positive electrode coated portion 111PA. Specifically, the positive electrode uncoated portion 111PB protrudes in the first direction Z1 side from the positive electrode coated portion 111PA. The positive electrode uncoated portion 111PB is bent radially inward about the winding axis α.

[0020] The positive electrode uncoated portion 111PB includes a plurality of extending portions 111PC. The extending portions 111PC are arranged in the winding direction of the wound electrode body 10.

[0021] Negative electrode 11N includes negative electrode current collector 111N and negative electrode mixture layer 112N. In the first embodiment, negative electrode current collector 111N is exemplified as the current collector in the present disclosure, and negative electrode mixture layer 112N is exemplified as the electrode mixture layer in the present disclosure.

[0022] The negative electrode current collector 111N has a sheet-like outer shape and is made of, for example, copper.

[0023] The negative electrode mixture layer 112N is formed on the negative electrode current collector 111N. Specifically, the negative electrode mixture layer 112N is applied to both radial surfaces of the negative electrode current collector 111N (negative electrode coating portion 111NA described later). The negative electrode mixture layer 112N is in close contact with the separator 12. The negative electrode mixture layer 112N is formed by applying a negative electrode slurry to the surface of the negative electrode current collector 111N and drying the coating. The negative electrode slurry is a slurry prepared by kneading the material of the negative electrode mixture layer 112N (negative electrode active material, binder, etc.) and a solvent. The thickness of the negative electrode mixture layer 112N is, for example, 0.1 μm or more and 1000 μm or less.

[0024] Negative electrode current collector 111N includes negative electrode coated portion 111NA and negative electrode uncoated portion 111NB. Negative electrode coated portion 111NA is a portion of negative electrode current collector 111N that is coated with negative electrode composite material layer 112N. In other words, negative electrode coated portion 111NA is a portion that is not exposed because it is covered with negative electrode composite material layer 112N.

[0025] The negative electrode uncoated portion 111NB is a portion that is not coated with the negative electrode composite layer 112N. In other words, the negative electrode uncoated portion 111NB is a portion of the negative electrode current collector 111N that is not covered with the negative electrode composite layer 112N and is exposed. The negative electrode uncoated portion 111NB is located on the second direction Z2 side along the axial direction from the negative electrode coated portion 111NA. The second direction Z2 is the opposite direction to the first direction Z1. The negative electrode uncoated portion 111NB protrudes from the negative electrode coated portion 111NA to one side in the axial direction Z of the wound electrode body 10. Specifically, the negative electrode uncoated portion 111NB protrudes from the negative electrode coated portion 111NA to the second direction Z2 side along the axial direction Z. The negative electrode uncoated portion 111NB is bent radially inward around the winding axis α.

[0026] The negative electrode uncoated portion 111NB includes a plurality of extending portions 111NC. The extending portions 111NC are arranged in the winding direction of the wound electrode body 10.

[0027] Next, the case 20 will be described. Fig. 3 is an exploded perspective view showing one of the storage cells according to the embodiment 1. Fig. 4 is another exploded perspective view showing the storage cell according to the embodiment 1.

[0028] 1, 3, and 4, the case 20 houses the wound electrode body 10. The case 20 includes a positive electrode terminal 21P, a negative electrode terminal 21N, a cylindrical wall portion 22, a bottom portion 23, a sealing plug 24, an external gasket 25, and an internal gasket 26. In the present embodiment, the negative electrode terminal 21N is exemplified as the external terminal in the present disclosure.

[0029] The positive electrode terminal 21P is disposed on the first direction Z1 side of the wound electrode body 10. The positive electrode terminal 21P includes a disk portion 211 and a rivet portion 212. The disk portion 211 is exposed to the outside. The rivet portion 212 is connected to the disk portion 211. The rivet portion 212 extends from the center of the disk portion 211 when viewed from the axial direction Z. The rivet portion 212 is located approximately on the winding axis α of the wound electrode body 10. The rivet portion 212 extends in the second direction Z2. The positive electrode terminal 21P is formed of aluminum, for example.

[0030] The negative electrode terminal 21N is provided so as to be perpendicular to the axial direction Z. A through hole 21Nh is provided in the negative electrode terminal 21N. Therefore, the negative electrode terminal 21N has an annular outer shape when viewed from the axial direction Z. The negative electrode terminal 21N is located between the disk portion 211 and the wound electrode body 10 in the axial direction Z. The rivet portion 212 is inserted through the through hole 21Nh. The rivet portion 212 extends to the inside of the case 20. The material constituting the negative electrode terminal 21N is not particularly limited, but is formed from aluminum, copper, stainless steel, or the like.

[0031] The cylindrical wall portion 22 is provided so as to cover the outer circumferential side of the wound electrode body 10. The cylindrical wall portion 22 covers the entire outer circumferential side of the wound electrode body 10. The cylindrical wall portion 22 has a cylindrical shape. An end portion of the cylindrical wall portion 22 on the first direction Z1 side is connected to the negative electrode terminal 21N. The negative electrode terminal 21N is formed integrally with the cylindrical wall portion 22. The material constituting the cylindrical wall portion 22 is not particularly limited, but is formed of a conductive material such as aluminum, copper, or stainless steel.

[0032] The bottom portion 23 is disposed on one side in the axial direction Z as viewed from the wound electrode body 10. When it is said that the negative electrode terminal 21N is connected to the other end of the cylindrical wall portion 22, it can be said that the bottom portion 23 is connected to one end of the cylindrical wall portion 22. Specifically, the bottom portion 23 is connected to the end portion of the cylindrical wall portion 22 on the second direction Z2 side.

[0033] The bottom 23 seals the opening of the cylindrical wall portion 22 on the second direction Z2 side. The bottom 23 is a sealing plate. The bottom 23 is joined to the cylindrical wall portion 22 by welding so that the negative electrode 11N is electrically connected to the negative electrode terminal 21N via the bottom 23 and the cylindrical wall portion 22. The outer peripheral edge of the bottom 23 is connected to the cylindrical wall portion 22 by welding such as laser welding. The material constituting the bottom 23 is not particularly limited, but is formed of a conductive material such as aluminum, copper, or stainless steel.

[0034] The bottom 23 is joined to the negative electrode uncoated portion 111NB by welding from the outside of the case 20. As a result, the bottom 23 is negatively charged. The cylindrical wall portion joined to the bottom 23 is also negatively charged. The negative electrode terminal 21N connected to the cylindrical wall portion 22 is also negatively charged. Note that in the energy storage cell 1, the bottom 23 can also be used as the negative electrode terminal.

[0035] The bottom portion 23 has an annular ridge portion 231, a plurality of radial ridge portions 232, and a plurality of welded portions 233. When viewed from the axial direction Z, the annular ridge portion 231 extends in an annular shape centered on the winding axis α of the wound electrode body 10. The annular ridge portion 231 protrudes toward the first direction Z1. That is, the annular ridge portion 231 protrudes toward the wound electrode body 10. The annular ridge portion 231 is in contact with the negative electrode uncoated portion 111NB of the negative electrode 11N.

[0036] The multiple radial protruding portions 232 are arranged so as to be spaced apart from each other in the circumferential direction centered on the winding axis α of the wound electrode body 10 as viewed from the axial direction Z. The multiple radial protruding portions 232 are arranged at equal intervals in the circumferential direction.

[0037] Each of the multiple radial ridge portions 232 extends in a radial direction centered on the winding axis α of the wound electrode body 10. The radial ridge portion 232 is continuous with the annular ridge portion 231.

[0038] The radial ridge portion 232 protrudes toward the first direction Z1. That is, the radial ridge portion 232 protrudes toward the wound electrode body 10. The radial ridge portion 232 is in contact with the negative electrode uncoated portion 111NB of the negative electrode 11N.

[0039] The welds 233 are portions of the bottom 23 that are joined to the negative electrode uncoated portion 111NB by welding. The welds 233 are formed by laser welding from the outside of the case 20 or the like. The welds 233 are formed on the annular convex stripe portion 231. In the annular convex stripe portion 231, the welds 233 are formed so as to extend along the circumferential direction. The welds 233 are formed on each of the radial convex stripes 232. In the radial convex stripe portion 232, the welds 233 are formed so as to extend along the radial direction. The annular convex stripe portion 231 and the radial convex stripes 232 may be thinner than other portions of the bottom 23. This makes it easier to form the welds 233.

[0040] A through hole 23h is formed in the bottom portion 23. The through hole 23h may be used to inject an electrolyte (not shown) to be contained in the case 20. The through hole 23h is formed in the center of the bottom portion 23 when viewed from the axial direction Z.

[0041] The sealing plug 24 is inserted into the through hole 23h of the bottom 23. This fixes the sealing plug 24 to the bottom 23. The sealing plug 24 and the through hole 23h can function as a pressure relief valve for releasing the pressure inside the case 20 when the pressure inside the case 20 becomes excessively high.

[0042] The external gasket 25 is disposed between the positive electrode terminal 21P and the negative electrode terminal 21N. The external gasket 25 is formed of an insulating material. Therefore, the external gasket 25 insulates the positive electrode terminal 21P from the negative electrode terminal 21N. The external gasket 25 covers the surface of the disk portion 211 on the second direction Z2 side. The rivet portion 212 penetrates the external gasket 25 in the axial direction Z. The external gasket 25 covers the inner surface in the radial direction of the through hole 21Nh of the negative electrode terminal 21N.

[0043] The internal gasket 26 covers the surface of the negative electrode terminal 21N on the second direction Z2 side. The internal gasket 26 is made of an insulating material. Therefore, the internal gasket 26 insulates the wound electrode body 10 from the negative electrode terminal 21N. The rivet portion 212 further penetrates the internal gasket 26 in the axial direction Z. Therefore, the rivet portion 212 is exposed to the inside of the case 20.

[0044] Next, a description will be given of the positive current collector 30. As shown in Figures 1 and 3, the positive current collector 30 is disposed inside the case 20. The positive current collector 30 is disposed on the side of the wound electrode body 10 in the first direction Z1.

[0045] The positive electrode current collector 30 is provided to electrically connect the positive electrode 11P and the positive electrode terminal 21P. The positive electrode current collector 30 is joined to the positive electrode uncoated portion 111PB of the positive electrode 11P by welding. As a result, the positive electrode current collector 30 is positively charged. The positive electrode current collector 30 is joined to the end of the rivet portion 212 of the positive electrode terminal 21P on the second direction Z2 side by welding. As a result, the positive electrode terminal 21P is positively charged.

[0046] An internal gasket 26 is disposed between the positive current collector plate 30 and the negative terminal 21N. This electrically insulates the positive current collector plate 30 and the negative terminal 21N from each other. The internal gasket 26 also extends to the outer periphery of the positive current collector plate 30. This also places the internal gasket 26 between the positive current collector plate 30 and the cylindrical wall portion 22. This electrically insulates the positive current collector plate 30 and the cylindrical wall portion 22 from each other.

[0047] The positive current collector plate 30 has a generally circular plate-like shape and includes a central portion 31, an outer peripheral edge portion 32, a plurality of spokes 33, and a plurality of pieces .

[0048] The central portion 31 is positioned so as to overlap the rivet portion 212 of the positive electrode terminal 21P when viewed from the axial direction Z. The central portion 31 is connected to the case 20, whereby the positive electrode current collector 30 is electrically connected to the positive electrode terminal 21P. Specifically, the central portion 31 is joined to the rivet portion 212 of the positive electrode terminal 21P by welding.

[0049] The outer peripheral edge portion 32 is provided on the outer peripheral edge of the positive electrode current collector plate 30. The outer peripheral edge portion 32 is located on the outer peripheral side of the central portion 31. The outer peripheral edge portion 32 extends in an annular shape with the central portion 31 as the center. The outer peripheral edge portion 32 may be in contact with the positive electrode uncoated portion 111PB of the positive electrode 11P. However, the outer peripheral edge portion 32 is not joined to the positive electrode uncoated portion 111PB.

[0050] The multiple spokes 33 are spaced apart from one another. The multiple spokes 33 are arranged at equal intervals in the circumferential direction centered on the central portion 31. The spokes 33 connect the central portion 31 and the outer peripheral edge portion 32. The spokes 33 have an outer shape such that the width dimension is approximately equal from the central portion 31 to the outer peripheral edge portion 32.

[0051] The pieces 35 are spaced apart from one another. The pieces 35 are arranged at equal intervals in the circumferential direction centered on the central portion 31. The spokes 33 and the pieces 35 are arranged such that the spokes 33 and the pieces 35 alternate in the circumferential direction centered on the central portion 31.

[0052] The piece 35 extends from the outer peripheral edge 32 toward the central portion 31. The piece 35 is connected to the positive electrode 11P. Specifically, the piece 35 is joined to the positive electrode uncoated portion 111PB of the positive electrode 11P by welding. FIG. 5 shows a schematic diagram of a path PP on the positive electrode current collector plate 30 from the joint between the piece 35 and the positive electrode uncoated portion 111PB to the joint between the central portion 31 and the rivet portion 212.

[0053] The piece 35 has a sectorial portion 351 and a neck portion 352. The sectorial portion 351 is joined to the positive electrode uncoated portion 111PB of the positive electrode 11P by welding. The tip of the sectorial portion 351 faces the central portion 31. The sectorial portion 351 extends toward the outer peripheral edge portion 32 so as to follow two adjacent spokes 33 on both sides in the circumferential direction. This makes the surface area of ​​the sectorial portion 351 relatively large, facilitating welding to the positive electrode uncoated portion 111PB of the positive electrode 11P.

[0054] The neck portion 352 connects the outer peripheral edge portion 32 and the sectorial portion 351. The neck portion 352 may contact the positive electrode uncoated portion 111PB of the positive electrode 11P. However, the neck portion 352 is not joined to the positive electrode uncoated portion 111PB of the positive electrode 11P. The dimension of the neck portion 352 in the circumferential direction is smaller than the dimension of the outer peripheral edge of the sectorial portion 351 in the circumferential direction. This makes it easier for the piece portion 35 to bend at the neck portion 352.

[0055] Here, an example of a method for welding the central portion 31 and the rivet portion 212 in this embodiment will be described. First, before the central portion 31 is welded to the rivet portion 212, the fan-shaped portion 351 of the piece portion 35 is welded to the positive electrode uncoated portion 111PB of the positive electrode 11P in advance. Next, a welding device is inserted from the second direction Z2 side of the wound electrode body 10 along the winding axis α of the wound electrode body 10. Then, while the welding device is pressed against the central portion 31 from the second direction Z2 side, the welding device welds the central portion 31 and the rivet portion 212 to each other. At this time, on the path PP, the connection portion between the spoke 33 and the central portion 31 and the connection portion between the spoke 33 and the outer circumferential edge portion 32 are largely deflected. This allows the central portion 31 to be easily displaced in the axial direction Z relative to the piece portion 35. Therefore, even if a welding device is pressed against the central portion 31, the bond between the piece portion 35 and the positive electrode uncoated portion 111PB is prevented from being destroyed due to the displacement of the central portion 31. As a result, the connection between the positive electrode current collector plate 30 and the case 20 is facilitated.

[0056] As described above, the energy storage cell 1 according to the first embodiment of the present disclosure includes a wound electrode body 10 and a case 20. The wound electrode body 10 includes a wound negative electrode 11N and a wound positive electrode 11P. The negative electrode 11N includes a sheet-shaped negative electrode current collector 111N and a negative electrode composite layer 112N formed on the negative electrode current collector 111N. The negative electrode current collector 111N includes a negative electrode coated portion 111NA coated with the negative electrode composite layer 112N, and a negative electrode uncoated portion 111NB not coated with the negative electrode composite layer 112N. The negative electrode uncoated portion 111NB protrudes from the negative electrode coated portion 111NA to one side in the axial direction Z of the wound electrode body 10. The case 20 accommodates the wound electrode body 10. The case 20 includes a cylindrical wall portion 22 and a bottom portion 23. The cylindrical wall portion 22 is provided so as to cover the outer peripheral side of the wound electrode body 10. The bottom portion 23 is disposed on one side in the axial direction Z and is connected to one end of the cylindrical wall portion 22. The bottom portion 23 is joined to the negative electrode uncoated portion 111NB by welding from the outside of the case 20.

[0057] According to the above configuration, the bottom 23 of the case 20 has a current collecting function for the negative electrode 11N. Therefore, a current collecting plate, which is a member different from the case 20, is not required for the negative electrode 11N, and the number of parts of the energy storage cell 1 can be reduced. This increases the space in the case 20 that can accommodate the wound electrode body 10, making it possible to accommodate a larger wound electrode body 10. As a result, the energy density of the energy storage cell 1 is further improved.

[0058] Furthermore, in this embodiment, the case 20 further includes a negative electrode terminal 21N connected to the other end of the cylindrical wall portion 22 and integrally formed with the cylindrical wall portion 22. The bottom portion 23 is joined to the cylindrical wall portion 22 by welding such that the negative electrode 11N is electrically connected to the negative electrode terminal 21N via the bottom portion 23 and the cylindrical wall portion 22.

[0059] Even when the negative electrode terminal 21N is relatively far from the bottom 23 as in the above configuration, the negative electrode 11N can be electrically connected to the negative electrode terminal 21N via the bottom 23 without using a member different from the case 20. As a result, the energy density of the storage cell 1 can be increased.

[0060] (Embodiment 2) Next, a description will be given of a storage cell according to a second embodiment of the present disclosure. In the second embodiment of the present disclosure, a part of the configuration of the case 20 differs from that of the first embodiment of the present disclosure. Therefore, the description of the same configuration and effects as those of the first embodiment of the present disclosure will not be repeated.

[0061] Fig. 5 is a cross-sectional view of a storage cell according to embodiment 2. As shown in Fig. 5, in embodiment 2 of the present disclosure, the negative electrode terminal 21Na is joined by welding to the other end of the cylindrical wall portion 22. The bottom portion 23a is integrally formed with the cylindrical wall portion 22 such that the negative electrode 11N is electrically connected to the negative electrode terminal 21Na via the bottom portion 23a and the cylindrical wall portion 22.

[0062] Even when the external terminal (negative electrode terminal 21Na) is relatively far from the bottom 23a as in the above configuration, the first electrode (negative electrode 11N) can be electrically connected to the external terminal (negative electrode terminal 21Na) via the bottom 23a without using a member different from the case 20. As a result, the energy density of the storage cell 1a can be increased. In this embodiment, the negative electrode terminal 21Na is exemplified as the external terminal in the present disclosure.

[0063] The case 20 further includes an annular weld 27a. The annular weld 27a is formed by joining the cylindrical wall 22 and the negative electrode terminal 21Na to each other by laser welding or the like. When viewed from the axial direction Z, the annular weld 27a extends in an annular shape along the outer circumferential edge of the negative electrode terminal 21Na.

[0064] The embodiments disclosed herein should be considered to be illustrative and not restrictive in all respects. The scope of the present disclosure is defined by the claims, not by the description of the embodiments described above, and is intended to include all modifications within the meaning and scope of the claims. [Explanation of symbols]

[0065] 1, 1a storage cell, 10 wound electrode body, 11N negative electrode, 111N negative electrode current collector, 111NA negative electrode coated portion, 111NB negative electrode uncoated portion, 112N negative electrode composite layer, 11P positive electrode, 111P positive electrode current collector, 111PA positive electrode coated portion, 111PB positive electrode uncoated portion, 112P positive electrode composite layer, 12 separator, 20 case, 21N, 21Na negative electrode terminal, 21P positive electrode terminal, 211 disk portion, 212 rivet portion, 22 cylindrical wall portion, 23, 23a bottom portion, 231 annular ridge portion, 232 radial ridge portion, 233 weld portion, 24 sealing plug, 25 external gasket, 26 internal gasket, 27a annular weld portion, 30 Positive current collecting plate, 31 central portion, 32 outer peripheral edge portion, 33 spokes, 35 one portion, 351 fan-shaped portion, 352 neck portion.

Claims

1. a wound electrode body including a wound first electrode and a wound second electrode; A case that houses the wound electrode body, The first electrode includes a sheet-shaped current collector and an electrode mixture layer formed on the current collector, the current collector includes a coated portion to which the electrode mixture layer is applied and an uncoated portion to which the electrode mixture layer is not applied, The uncoated portion protrudes from the coated portion to one side in the axial direction of the wound electrode body, the case includes a cylindrical wall portion provided to cover an outer circumferential side of the wound electrode body, and a bottom portion disposed on one side in the axial direction and connected to one end of the cylindrical wall portion, The bottom portion is joined to the uncoated portion by welding from the outside of the case.

2. the case further includes an external terminal connected to the other end of the cylindrical wall portion and integrally formed with the cylindrical wall portion, The energy storage cell according to claim 1 , wherein the bottom portion is joined to the cylindrical wall portion by welding such that the first electrode is electrically connected to the external terminal via the bottom portion and the cylindrical wall portion.

3. the case further includes an external terminal joined to the other end of the cylindrical wall portion by welding; The energy storage cell according to claim 1 , wherein the bottom portion is integrally formed with the cylindrical wall portion such that the first electrode is electrically connected to the external terminal via the bottom portion and the cylindrical wall portion.

Images