Battery cell

Abstract

The utility model relates to a single storage battery. In a storage cell according to the present disclosure, a first electrode of a wound electrode body 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 toward one side in the axial direction of the wound electrode body. The case accommodates the wound electrode body and includes a cylindrical wall portion and a bottom portion. The cylindrical wall portion is provided so as to cover the outer peripheral side of the wound electrode body. The bottom portion is disposed on one side in the axial direction, is connected to one end of the cylindrical wall portion, and is joined to the uncoated portion by welding.

Description

Technical Field

[0001] The present disclosure relates to a power storage cell. Background Art

[0002] Japanese Patent Application Laid-Open No. 10-162854 discloses a cylindrical battery having a spiral electrode group and a tabless current collection method. A generally disc-shaped current collector is welded to the conductive edge of the negative electrode plate, which protrudes outward from the upper and lower end surfaces of the electrode group. Utility Model Content

[0003] In a power storage cell (power storage unit) such as the cylindrical battery disclosed in Japanese Patent Application Laid-Open No. 10-162854, there is room for further reducing the number of components and further improving the energy density per unit volume of the cell.

[0004] The present disclosure has been made in view of the above-mentioned problems, and an object of the present disclosure is to provide a power storage cell capable of further improving energy density.

[0005] The electric storage cell according to the present disclosure includes a wound electrode body and a case.

[0006] The wound electrode body includes a wound first electrode and a wound second electrode.

[0007] The first electrode includes a sheet-shaped current collector and an electrode mixture layer formed on the current collector.

[0008] The current collector includes a coated portion coated with the electrode mixture layer and an uncoated portion not coated with the electrode mixture layer.

[0009] The uncoated portion protrudes from the coated portion toward one side in the axial direction of the wound electrode body.

[0010] The case accommodates the wound electrode body and includes a cylindrical wall portion and a bottom portion.

[0011] The cylindrical wall portion is provided so as to cover the outer peripheral side of the wound electrode body.

[0012] The bottom portion is arranged on one side in the axial direction and is connected to one end of the cylindrical wall portion.

[0013] The bottom portion is joined to the uncoated portion by welding from the outside of the housing.

[0014] With this configuration, the bottom of the casing serves as the current collector for the first electrode. Therefore, a separate current collector plate is no longer required for the first electrode, reducing the number of components in the battery cell. This increases the space within the casing for the wound electrode assembly, allowing for larger wound electrode assemblies. As a result, the energy density of the battery cell is further improved.

[0015] According to the present disclosure, it is possible to provide a power storage cell having a further improved energy density. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The features, advantages, and technical and industrial significance of exemplary embodiments of the present invention will be described below with reference to the accompanying drawings, in which like reference numerals represent like elements, and wherein:

[0017] Figure 1 is a cross-sectional view showing a power storage cell according to the first embodiment;

[0018] Figure 2 This is a perspective view showing a partially exploded wound electrode body;

[0019] Figure 3 This is an exploded perspective view showing the power storage cell according to the first embodiment;

[0020] Figure 4 is another exploded perspective view showing the power storage cell according to the first embodiment; and

[0021] Figure 5 It is a cross-sectional view of a power storage cell according to the second embodiment. DETAILED DESCRIPTION

[0022] Hereinafter, the power storage cells according to the various embodiments of the present disclosure will be described with reference to the accompanying drawings. The same or corresponding parts in the drawings are denoted by the same reference numerals, and their description will not be repeated.

[0023] Implementation Method 1

[0024] Figure 1 1 is a cross-sectional view showing the storage battery cell according to the first embodiment. Figure 1 As shown, the electricity storage cell 1 according to the first embodiment of the present disclosure includes a wound electrode body 10 , a case 20 , and a positive electrode current collecting plate 30 .

[0025] First, the wound electrode body 10 will be described. Figure 2 This is a perspective view showing a partially exploded wound electrode body. Figure 1 as well as Figure 2 As shown, the wound electrode body 10 is wound in a cylindrical shape. Figure 2 , a state in which the wound electrode body 10 is slightly unwound is shown.

[0026] 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 and the positive electrode 11P is exemplified as the second electrode. Alternatively, the first electrode may be a positive electrode and the second electrode may be a negative electrode.

[0027] The positive electrode 11P and the negative electrode 11N have a sheet-like outer shape. The wound electrode body 10 is composed of an electrode plate group in which the positive electrode 11P and the negative electrode 11N are wound with a separator 12 interposed therebetween.

[0028] The separator 12 is provided between the positive electrode 11P and the negative electrode 11N. The separator 12 allows ions (eg, lithium ions) to flow between the positive electrode 11P (positive electrode active material) and the negative electrode 11N (negative electrode active material) and separates the positive electrode 11P from the negative electrode 11N.

[0029] The positive electrode 11P includes a positive electrode current collector 111P and a positive electrode mixture layer 112P. The positive electrode current collector 111P is made of, for example, aluminum.

[0030] The positive electrode mixture layer 112P is applied to both radial surfaces of the positive electrode current collector 111P (the positive electrode coating portion 111PA described below). 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 the positive electrode slurry. Positive electrode slurry is a slurry prepared by mixing the materials (positive electrode active material, binder, etc.) of the positive electrode mixture layer 112P with a solvent. The thickness of the positive electrode mixture layer 112P is, for example, not less than 0.1 μm and not more than 1000 μm.

[0031] The positive electrode current collector 111P includes a positive electrode coating portion 111PA and a positive electrode uncoated portion 111PB. The positive electrode coating portion 111PA is the portion of the positive electrode current collector 111P coated with the positive electrode mixture layer 112P. In other words, the positive electrode coating portion 111PA is the portion covered by the positive electrode mixture layer 112P and not exposed.

[0032] The positive electrode uncoated portion 111PB is the exposed portion of the positive electrode current collector 111P that is not covered by the positive electrode mixture layer 112P. The positive electrode uncoated portion 111PB is located closer to the first direction Z1 along the axial direction Z than the positive electrode coated portion 111PA. Specifically, the positive electrode uncoated portion 111PB protrudes from the positive electrode coated portion 111PA in the first direction Z1. The positive electrode uncoated portion 111PB is bent radially inward about the winding axis α.

[0033] The positive electrode uncoated portion 111PB includes a plurality of extending portions 111PC. The plurality of extending portions 111PC are arranged along the winding direction of the wound electrode body 10.

[0034] The negative electrode 11N includes a negative electrode current collector 111N and a negative electrode mixture layer 112N. In the first embodiment, the negative electrode current collector 111N is exemplified as the current collector in the present disclosure, and the negative electrode mixture layer 112N is exemplified as the electrode mixture layer in the present disclosure.

[0035] The negative electrode current collector 111N has a sheet-like outer shape and is made of, for example, copper.

[0036] The negative electrode mixture layer 112N is formed on the negative electrode collector 111N. Specifically, the negative electrode mixture layer 112N is applied to both radial surfaces of the negative electrode 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 collector 111N and drying the negative electrode slurry. The negative electrode slurry refers to a slurry prepared by mixing the materials of the negative electrode mixture layer 112N (negative electrode active material, binder, etc.) with a solvent. The thickness of the negative electrode mixture layer 112N is, for example, not less than 0.1 μm and not more than 1000 μm.

[0037] The negative electrode current collector 111N includes a negative electrode coating portion 111NA and a negative electrode uncoated portion 111NB. The negative electrode coating portion 111NA is the portion of the negative electrode current collector 111N coated with the negative electrode mixture layer 112N. In other words, the negative electrode coating portion 111NA is the portion covered by the negative electrode mixture layer 112N and not exposed.

[0038] The negative electrode uncoated portion 111NB is a portion that is not coated with the negative electrode mixture 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 by the negative electrode mixture layer 112N and is exposed. The negative electrode uncoated portion 111NB is located closer to the second direction Z2 along the axial direction than 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 along the axial direction Z. The negative electrode uncoated portion 111NB is bent radially inward with the winding axis α as the center.

[0039] The negative electrode uncoated portion 111NB includes a plurality of extending portions 111NC. The plurality of extending portions 111NC are arranged along the winding direction of the wound electrode body 10.

[0040] Next, the housing 20 will be described. Figure 3 This is an exploded perspective view showing the power storage cell according to the first embodiment. Figure 4 This is another exploded perspective view showing the power storage cell according to the first embodiment.

[0041] like Figure 1 、 Figure 3 as well as Figure 4As shown, case 20 houses wound electrode assembly 10. 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 this embodiment, negative electrode terminal 21N is exemplified as an external terminal in the present disclosure.

[0042] The positive terminal 21P is arranged on the first direction Z1 side of the wound electrode body 10. The positive 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 in the axial direction Z. The rivet portion 212 is approximately located on the winding axis α of the wound electrode body 10. The rivet portion 212 extends to the second direction Z2 side. The positive terminal 21P is formed, for example, of aluminum.

[0043] The negative terminal 21N is arranged so as to be perpendicular to the axial direction Z. A through-hole 21Nh is provided in the negative terminal 21N. Therefore, the negative terminal 21N has an annular shape when viewed from the axial direction Z. The negative 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 into the interior of the shell 20. The material constituting the negative terminal 21N is not particularly limited, and is formed of aluminum, copper, stainless steel, or the like.

[0044] The cylindrical wall portion 22 is provided so as to cover the outer circumference of the wound electrode body 10. The cylindrical wall portion 22 covers the entire outer circumference of the wound electrode body 10. The cylindrical wall portion 22 has a cylindrical shape. The end 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 and is formed from a conductive material such as aluminum, copper, or stainless steel.

[0045] The bottom portion 23 is located on one side in the axial direction Z when viewed from the wound electrode body 10. Since 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 side in the second direction Z2.

[0046] The bottom portion 23 seals the opening of the cylindrical wall portion 22 on the second direction Z2 side. The bottom portion 23 serves as a sealing plate. The bottom portion 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 portion 23 and the cylindrical wall portion 22. The outer periphery of the bottom portion 23 is joined to the cylindrical wall portion 22 by welding such as laser welding. The material constituting the bottom portion 23 is not particularly limited and is formed from a conductive material such as aluminum, copper, or stainless steel.

[0047] Bottom 23 is joined to negative electrode uncoated portion 111NB by welding from the outside of case 20. This causes bottom 23 to be negatively charged. The cylindrical wall portion joined to bottom 23 is also negatively charged. Negative electrode terminal 21N connected to cylindrical wall portion 22 is also negatively charged. Furthermore, bottom 23 can also be used as a negative electrode terminal in storage cell 1.

[0048] The bottom portion 23 includes an annular ridge portion 231, multiple radial ridge portions 232, and multiple welded portions 233. The annular ridge portion 231 extends annularly centered around the winding axis α of the wound electrode body 10 when viewed in the axial direction Z. 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 contacts the negative electrode uncoated portion 111NB of the negative electrode 11N.

[0049] The plurality of radial ridges 232 are arranged spaced apart from each other in the circumferential direction centered on the winding axis α of the wound electrode body 10 when viewed from the axial direction Z. The plurality of radial ridges 232 are arranged at equal intervals in the circumferential direction.

[0050] Each of the plurality of radial ridges 232 extends in the radial direction centered on the winding axis α of the wound electrode body 10 . The radial ridges 232 are connected to the annular ridge 231 .

[0051] The radial ridges 232 protrude toward the first direction Z1. That is, the radial ridges 232 protrude toward the wound electrode body 10. The radial ridges 232 are in contact with the negative electrode uncoated portion 111NB of the negative electrode 11N.

[0052] The plurality of welded portions 233 are portions of the bottom portion 23 that are joined to the negative electrode uncoated portion 111NB by welding. The plurality of welded portions 233 are formed by laser welding or the like from the outside of the housing 20. The plurality of welded portions 233 are formed on the annular ridge portion 231. In the annular ridge portion 231, the plurality of welded portions 233 are formed so as to extend in the circumferential direction. The plurality of welded portions 233 are respectively formed on the plurality of radial ridge portions 232. In the radial ridge portion 232, the welded portions 233 are formed so as to extend in the radial direction. The annular ridge portion 231 and the plurality of radial ridge portions 232 can be thinner than other portions of the bottom portion 23. This facilitates the formation of the welded portions 233.

[0053] A through hole 23h is formed in the bottom portion 23. The through hole 23h can also be used to inject an electrolyte (not shown) 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.

[0054] The sealing plug 24 is inserted through the through hole 23h of the bottom 23. Thus, the sealing plug 24 is fixed 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 housing 20 when the pressure inside the housing 20 becomes excessively high.

[0055] 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 side in the second direction Z2. The rivet portion 212 penetrates the external gasket 25 in the axial direction Z. The external gasket 25 covers the radially inner surface of the through-hole 21Nh of the negative electrode terminal 21N.

[0056] The internal gasket 26 covers the surface of the negative electrode terminal 21N on the side in the second direction Z2. The internal gasket 26 is formed of an insulating material. Therefore, the internal gasket 26 insulates the wound electrode body 10 from the negative electrode terminal 21N. The rivet 212 also penetrates the internal gasket 26 in the axial direction Z. Therefore, the rivet 212 is exposed inside the case 20.

[0057] Next, the positive electrode collector plate 30 will be described. Figure 1 as well as Figure 3 As shown, the positive electrode current collector plate 30 is disposed in the case 20. The positive electrode current collector plate 30 is disposed on the first direction Z1 side of the wound electrode body 10.

[0058] The positive electrode collector plate 30 is provided to electrically connect the positive electrode 11P and the positive electrode terminal 21P. The positive electrode collector plate 30 is welded to the positive electrode uncoated portion 111PB of the positive electrode 11P. This positively charges the positive electrode collector plate 30. The positive electrode collector plate 30 is welded to the end of the rivet portion 212 of the positive electrode terminal 21P on the side in the second direction Z2. This positively charges the positive electrode terminal 21P.

[0059] An internal gasket 26 is disposed between the positive electrode collector plate 30 and the negative electrode terminal 21N. This electrically insulates the positive electrode collector plate 30 and the negative electrode terminal 21N from each other. Furthermore, the internal gasket 26 extends toward the outer periphery of the positive electrode collector plate 30. This also places the internal gasket 26 between the positive electrode collector plate 30 and the cylindrical wall portion 22. Consequently, the positive electrode collector plate 30 and the cylindrical wall portion 22 are electrically insulated from each other.

[0060] The positive electrode current collector plate 30 has a substantially disk-shaped outer shape and includes a central portion 31 , an outer peripheral portion 32 , a plurality of spokes 33 , and a plurality of tabs 35 .

[0061] The central portion 31 is located so as to overlap with 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, thereby electrically connecting the positive electrode current collector plate 30 and 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.

[0062] 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 periphery of the central portion 31. The outer peripheral edge portion 32 extends in a circular shape centered on the central portion 31. The outer peripheral edge portion 32 can contact the positive electrode uncoated portion 111PB of the positive electrode 11P. However, the outer peripheral edge portion 32 does not bond to the positive electrode uncoated portion 111PB.

[0063] The spokes 33 are spaced apart from each other. The spokes 33 are arranged at equal intervals in the circumferential direction around the center portion 31. The spokes 33 connect the center portion 31 to the outer peripheral portion 32. The spokes 33 have an outer shape with a substantially uniform width from the center portion 31 to the outer peripheral portion 32.

[0064] The plurality of pieces 35 are separated from each other. The plurality of pieces 35 are arranged at equal intervals in the circumferential direction around the center portion 31. The plurality of spokes 33 and the plurality of pieces 35 are arranged so that the spokes 33 and the pieces 35 are alternately arranged in the circumferential direction around the center portion 31.

[0065] The sheet portion 35 extends from the outer peripheral edge portion 32 toward the central portion 31. The sheet portion 35 is connected to the positive electrode 11P. Specifically, the sheet portion 35 is joined to the positive electrode uncoated portion 111PB of the positive electrode 11P by welding. Figure 5 , a path PP on the positive electrode current collecting plate 30 from the joining portion between the sheet portion 35 and the positive electrode uncoated portion 111PB to the joining portion between the central portion 31 and the rivet portion 212 is schematically shown.

[0066] The piece 35 includes a fan-shaped portion 351 and a head portion 352. The fan-shaped portion 351 is joined to the positive electrode uncoated portion 111PB of the positive electrode 11P by welding. The tip of the fan-shaped portion 351 faces the central portion 31. The fan-shaped portion 351 extends toward the outer peripheral edge portion 32 along two adjacent spokes 33 on both sides in the circumferential direction. This provides a relatively large surface area of ​​the fan-shaped portion 351, facilitating welding to the positive electrode uncoated portion 111PB of the positive electrode 11P.

[0067] The head portion 352 connects the outer peripheral edge portion 32 to the fan-shaped portion 351. The head portion 352 can contact the positive electrode uncoated portion 111PB of the positive electrode 11P. However, the head portion 352 does not engage with the positive electrode uncoated portion 111PB of the positive electrode 11P. The circumferential dimension of the head portion 352 is smaller than the circumferential dimension of the outer peripheral edge of the fan-shaped portion 351. This facilitates the bending of the sheet portion 35 in the head portion 352.

[0068] Here, an example of a method for welding the central portion 31 and the rivet portion 212 in this embodiment is described. First, before the central portion 31 and the rivet portion 212 are welded, the fan-shaped portion 351 of the sheet portion 35 is preliminarily welded to the positive electrode uncoated portion 111PB of the positive electrode 11P. 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 central portion 31 and the rivet portion 212 are welded to each other by the welding device. 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 peripheral edge portion 32 are greatly bent. As a result, the central portion 31 can be relatively easily displaced in the axial direction Z relative to the sheet portion 35. Therefore, even if the welding device is pressed against the center portion 31, the displacement of the center portion 31 can prevent the bond between the sheet portion 35 and the positive electrode uncoated portion 111PB from being broken.

[0069] As described above, the 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-like negative electrode current collector 111N and a negative electrode mixture layer 112N formed on the negative electrode current collector 111N. The negative electrode current collector 111N includes a negative electrode coating portion 111NA coated with the negative electrode mixture layer 112N and a negative electrode uncoated portion 111NB not coated with the negative electrode mixture layer 112N. The negative electrode uncoated portion 111NB protrudes from the negative electrode coating 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 circumference of the wound electrode body 10. The bottom portion 23 is arranged 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.

[0070] With the above-described configuration, the bottom 23 of the case 20 performs the current collecting function for the negative electrode 11N. Therefore, a current collector plate separate from the case 20 is unnecessary for the negative electrode 11N, reducing the number of components in the electrical storage cell 1. This increases the space within the case 20 available to accommodate the wound electrode assembly 10, enabling the storage of a larger wound electrode assembly 10. As a result, the energy density of the electrical storage cell 1 is further improved.

[0071] Furthermore, in this embodiment, case 20 further includes a negative electrode terminal 21N connected to the other end of cylindrical wall portion 22 and formed integrally with cylindrical wall portion 22. Bottom portion 23 is joined to cylindrical wall portion 22 by welding so that negative electrode 11N is electrically connected to negative electrode terminal 21N via bottom portion 23 and cylindrical wall portion 22.

[0072] Even when negative terminal 21N is relatively far from bottom 23 as in the above configuration, negative electrode 11N and negative terminal 21N can be electrically connected via bottom 23 without using a member separate from case 20. As a result, the energy density of storage cell 1 can be further increased.

[0073] Implementation Method 2

[0074] Next, a storage cell according to Embodiment 2 of the present disclosure will be described. Embodiment 2 of the present disclosure differs from Embodiment 1 of the present disclosure in that a portion of the configuration of case 20 is different. Therefore, descriptions of the same configurations and effects as those of Embodiment 1 will not be repeated.

[0075] Figure 5 : is a cross-sectional view of a storage battery cell according to Embodiment 2. Figure 5 As shown, in the second embodiment of the present disclosure, the negative electrode terminal 21Na is joined to the other end of the cylindrical wall portion 22 by welding. Furthermore, the bottom portion 23a is integrally formed with the cylindrical wall portion 22 so 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.

[0076] Even when the external terminal (negative electrode terminal 21Na) is relatively far from the bottom portion 23a as in the above-described configuration, the first electrode (negative electrode 11N) can be electrically connected to the external terminal (negative electrode terminal 21Na) via the bottom portion 23a without using a separate member from the case 20. As a result, the energy density of the power storage cell 1a can be further increased. In this embodiment, the negative electrode terminal 21Na is exemplified as an external terminal in this disclosure.

[0077] The case 20 further includes an annular weld portion 27a. The annular weld portion 27a is formed by joining the cylindrical wall portion 22 and the negative electrode terminal 21Na to each other by laser welding or the like. The annular weld portion 27a extends annularly along the outer periphery of the negative electrode terminal 21Na when viewed in the axial direction Z.

[0078] The embodiments disclosed herein are to be considered in all respects as illustrative and non-restrictive. The scope of the present disclosure is indicated not by the above description of the embodiments but by the claims, and is intended to include all modifications within the meaning and scope equivalent to the claims.

Claims

1. A storage battery comprising: a wound electrode body including a wound first electrode and a wound second electrode; and a housing for housing 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 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 toward one side in the axial direction of the wound electrode body. The case includes a cylindrical wall portion and a bottom portion, wherein the cylindrical wall portion is provided so as to cover the outer circumference of the wound electrode body, and the bottom portion is arranged 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 housing.

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

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

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