Electricity storage unit

Abstract

The present disclosure relates to a power storage unit. In an electricity storage unit, a collector plate includes a center portion, an outer peripheral edge portion, spokes, a first piece portion, and a second piece portion. The central portion is disposed so as to overlap the center of the wound electrode body when viewed from the axial direction. The outer peripheral edge portion is located on the outer peripheral side of the central portion. The collector plate is electrically connected to the first external terminal by being connected to the housing through either the outer peripheral edge portion or the central portion. The spokes connect the central portion and the outer peripheral edge portion. The first sheet portion extends from the central portion toward the outer peripheral edge portion and is connected to the first electrode. The second sheet portion extends from the outer peripheral edge portion toward the central portion and is connected to the first electrode.

Description

Technical Field

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

[0002] Japanese Patent No. 3324372 discloses a cylindrical battery in which an electrode assembly consisting of a positive electrode, a negative electrode, and a separator is spirally wound and housed in a battery container. A tabless method is described as a method for connecting the positive electrode lead. The lead of the current collector plate provided on the positive electrode is welded to the back of the lid. The overlapping lead of the negative electrode is spot welded to the inner bottom of the casing. Utility Model Content

[0003] Storage cells, such as the cylindrical batteries disclosed in Japanese Patent No. 3324372, are sometimes charged via rapid charging. During rapid charging, the temperature of the storage cell is expected to rise to a certain degree. However, to maintain the function of the storage cell, it is necessary to suppress excessive heat generation within the storage 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 unit that can appropriately generate heat when energized.

[0005] The storage cell disclosed herein comprises a wound electrode body, a casing and a collector plate. The wound electrode body comprises a first electrode and a second electrode. The casing houses the wound electrode body and comprises a first external terminal. The collector plate is arranged on one side of the wound electrode body in the axial direction within the casing. The collector plate is provided to separate the first electrode and the first external terminal. The collector plate comprises a central portion, an outer peripheral portion, spokes, a first sheet portion and a second sheet portion. The central portion is arranged so as to overlap with the center of the wound electrode body when viewed from the axial direction. The outer peripheral portion is located on the outer peripheral side of the central portion. The collector plate is electrically connected to the first external terminal by being connected to the casing via either the outer peripheral portion or the central portion. The spokes connect the central portion and the outer peripheral portion. The first sheet portion extends from the central portion toward the outer peripheral portion and is connected to the first electrode. The second sheet portion extends from the outer peripheral portion toward the central portion and is connected to the first electrode.

[0006] In the above configuration, first, for example, when the outer peripheral portion is connected to the housing, the path along the current collector plate, which connects in the order of the first sheet, central portion, spokes, and outer peripheral portion, is relatively long. Consequently, when power is applied to the storage cell, the current collector plate generates relatively high heat along this path. Meanwhile, the path along the current collector plate, which consists only of the second sheet and outer peripheral portion, is relatively short. Consequently, heat generated along this path during power application is relatively low. This allows for a storage cell that generates moderate heat during power application. Furthermore, second, for example, when the central portion is connected to the housing, the path along the current collector plate, which connects in the order of the second sheet, outer peripheral portion, spokes, and central portion, is relatively long. Consequently, when power is applied to the storage cell, the current collector plate generates relatively high heat along this path. Meanwhile, the path along the current collector plate, which consists only of the first sheet and central portion, is relatively short. Consequently, heat generated along this path during power application is relatively low. This allows for a storage cell that generates moderate heat during power application.

[0007] In the electricity storage unit according to the present disclosure, preferably, the first sheet portion and the second sheet portion are arranged with spokes interposed therebetween in a circumferential direction centered around the central portion.

[0008] According to the above configuration, the long paths on the collector plates that generate relatively high heat when current is applied and the short paths on the collector plates that generate relatively low heat are arranged circumferentially. This can reduce the circumferential dispersion of heat distribution on the collector plates when current is applied.

[0009] In the electricity storage unit according to the present disclosure, it is preferable that the first sheet portion and the second sheet portion are arranged in a radial direction centered on the central portion. According to this configuration, the first sheet portion and the second sheet portion can be arranged compactly.

[0010] In the electricity storage cell according to the present disclosure, it is preferable that the first piece portion and the second piece portion are welded to the first electrode 11A.

[0011] According to the above configuration, the first sheet portion and the second sheet portion are securely fixedly connected by the first electrode. Furthermore, the conductive path through the first sheet portion and the conductive path through the second sheet portion in the current collector plate are more securely formed.

[0012] In the electricity storage unit according to the present disclosure, the outer case preferably includes a cylindrical wall portion that covers the entire outer periphery of the wound electrode assembly. The outer peripheral edge portion is connected to the cylindrical wall portion, electrically connecting the current collector plate to the first external terminal.

[0013] According to the above configuration, the conductive path from the current collector plate to the first external terminal includes the cylindrical wall portion having a relatively large outer surface area. This allows heat generated in the conductive path during current flow to be easily dissipated from the outer surface of the cylindrical wall portion.

[0014] In the electricity storage unit according to the present disclosure, the first external terminal is preferably located so as to overlap with the central portion when viewed in the axial direction. The current collector plate is electrically connected to the first external terminal by connecting the central portion to the housing.

[0015] According to the above configuration, the conductive path from the current collector plate to the first external terminal can be shortened, and heat generation in the conductive path can be suppressed.

[0016] The foregoing and other objects, features, aspects and advantages of the present invention will become more apparent from the following detailed description of the present invention when taken in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 This is a perspective view showing the power storage unit according to the first embodiment.

[0018] Figure 2 It will Figure 1 A cross-sectional view of the power storage unit when viewed in the direction of the arrow on line II-II.

[0019] Figure 3 It will Figure 1 A cross-sectional view of the power storage unit when viewed in the direction of the arrow on line III-III.

[0020] Figure 4 This is a perspective view showing a partially exploded wound electrode body.

[0021] Figure 5 This is an exploded perspective view showing the power storage unit according to the first embodiment.

[0022] Figure 6 This is another exploded perspective view showing the power storage unit according to the first embodiment.

[0023] Figure 7 This is a plan view showing the negative electrode current collector plate in the first embodiment.

[0024] Figure 8 This is a cross-sectional view showing a power storage unit according to the second embodiment.

[0025] Figure 9 This is a plan view showing a negative electrode current collector plate in the second embodiment.

[0026] Figure 10 This is a cross-sectional view of a power storage unit according to the third embodiment.

[0027] Figure 11 This is another cross-sectional view of the power storage unit according to the third embodiment.

[0028] Figure 12This is an exploded perspective view showing the power storage unit according to the third embodiment.

[0029] Figure 13 This is another exploded perspective view showing the power storage unit according to the third embodiment.

[0030] Figure 14 This is a plan view showing a positive electrode current collecting plate in the third embodiment.

[0031] Figure 15 This is a cross-sectional view showing a power storage unit according to the fourth embodiment.

[0032] Figure 16 This is a plan view showing a positive electrode current collecting plate in the fourth embodiment.

[0033] Figure 17 This is a cross-sectional view of a power storage unit according to the fifth embodiment.

[0034] Figure 18 This is an exploded perspective view showing the power storage unit according to the fifth embodiment in an exploded manner. DETAILED DESCRIPTION

[0035] Hereinafter, the power storage unit according to each embodiment of the present disclosure will be described with reference to the attached drawings. Figure 1 The same or corresponding parts in the drawings are denoted by the same reference numerals, and their description will not be repeated.

[0036] (Implementation 1)

[0037] Figure 1 This is a perspective view showing the power storage unit according to the first embodiment. Figure 2 It will Figure 1 A cross-sectional view of the power storage unit when viewed in the direction of the arrow on line II-II. Figure 3 It will Figure 1 A cross-sectional view of the power storage unit when viewed in the direction of the arrow on line III-III.

[0038] like Figures 1 to 3 As shown, the storage cell 1 is a cylindrical battery. The storage cell 1 includes a wound electrode body 10, a case 20, a positive electrode collector plate 30P, and a negative electrode collector plate 30N. In the first embodiment, the negative electrode collector plate 30N is exemplified as the collector plate (30) in the present disclosure.

[0039] First, the wound electrode body 10 will be described. Figure 4 This is a perspective view showing a partially exploded wound electrode body. Figures 2 to 4 As shown, the wound electrode body 10 is wound in a cylindrical shape. Figure 4 , a state in which the winding of the wound electrode body 10 is slightly loosened is shown.

[0040] The wound electrode body 10 includes a positive electrode 11P, a negative electrode 11N, and a separator 12. The wound electrode body 10 is wound so that the positive electrode 11P, the negative electrode 11N, and the separator 12 surround the winding axis α. In the first embodiment, the negative electrode 11N is exemplified as the first electrode (11A) in the present disclosure, and the positive electrode 11P is exemplified as the second electrode (11B).

[0041] 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.

[0042] 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.

[0043] The positive electrode 11P includes a positive electrode current collector 111P and a positive electrode composite material (positive electrode mixture) layer 112P. The positive electrode current collector 111P is made of, for example, aluminum.

[0044] The positive electrode composite material 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 composite material layer 112P is in close contact with the separator 12. The positive electrode composite material 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 prepared by mixing the materials of the positive electrode composite material layer 112P (positive electrode active material, binder, etc.) with a solvent. The thickness of the positive electrode composite material layer 112P is, for example, not less than 0.1 μm and not more than 1000 μm.

[0045] 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 composite material layer 112P. In other words, the positive electrode coating portion 111PA is the portion not exposed due to being covered by the positive electrode composite material layer 112P.

[0046] 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 composite material 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.

[0047] The positive electrode uncoated portion 111PB includes a plurality of extension portions 111PC. The plurality of extension portions 111PC are arranged along the winding direction of the wound electrode body 10.

[0048] The negative electrode 11N includes a negative electrode current collector 111N and a negative electrode composite material (negative electrode mixture) layer 112N. The negative electrode current collector 111N is made of, for example, copper.

[0049] The negative electrode composite material layer 112N is applied to both radial surfaces of the negative electrode current collector 111N (negative electrode coating portion 111NA, described below). The negative electrode composite material layer 112N is in close contact with the separator 12. The negative electrode composite material layer 112N is formed by applying a negative electrode slurry to the surface of the negative electrode current collector 111N and drying it. The negative electrode slurry is prepared by mixing the materials of the negative electrode composite material layer 112N (negative electrode active material, binder, etc.) with a solvent. The thickness of the negative electrode composite material layer 112N is, for example, not less than 0.1 μm and not more than 1000 μm.

[0050] 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 not exposed due to being covered by the negative electrode mixture layer 112N.

[0051] The negative electrode uncoated portion 111NB is the exposed portion of the negative electrode current collector 111N that is not covered by the negative electrode composite material layer 112N. The negative electrode uncoated portion 111NB is located closer to the negative electrode coated portion 111NA in the second direction Z2 along the axial direction. The second direction Z2 is opposite to the first direction Z1. The negative electrode uncoated portion 111NB protrudes from the negative electrode coated portion 111NA in the second direction Z2 along the axial direction Z. The negative electrode uncoated portion 111NB is bent radially inward.

[0052] The negative electrode uncoated portion 111NB includes a plurality of extensions 111NC. The plurality of extensions 111NC are arranged along the winding direction of the wound electrode body 10.

[0053] Next, the housing 20 will be described. Figure 5 This is an exploded perspective view showing the power storage unit according to the first embodiment. Figure 6 This is another exploded perspective view showing the power storage unit according to the first embodiment.

[0054] like Figures 1 to 3 、 Figure 5 and Figure 6As shown, 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 sealing plate 23, a sealing plug 24, an external gasket 25, an internal gasket 26, and an annular gasket 27. In the first embodiment, the negative electrode terminal 21N is exemplified as the first external terminal (21A) in the present disclosure, and the positive electrode terminal 21P is exemplified as the second external terminal (21B) in the present disclosure.

[0055] The positive electrode terminal 21P is arranged 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 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 electrode terminal 21P is formed of, for example, aluminum.

[0056] 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 to the interior of the outer shell 20. The material constituting the negative terminal 21N is not particularly limited, but is formed of aluminum, copper, stainless steel, or the like.

[0057] The cylindrical wall portion 22 is provided on 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 cylindrical wall portion 22 is integrally formed with the negative electrode terminal 21N. The material constituting the cylindrical wall portion 22 is not particularly limited, but is formed from aluminum, copper, stainless steel, or the like.

[0058] A tightening (caulking) portion 22d is formed at the end portion of the cylindrical wall portion 22 on the second direction Z2 side. The tightening portion 22d is formed in an annular shape along the circumferential direction of the wound electrode body 10. Figure 5 and Figure 6 , the cylindrical wall portion 22 is shown in a state before the tightening portion 22d is formed.

[0059] The sealing plate 23 is connected to the end portion of the cylindrical wall portion 22 on the second direction Z2 side. The sealing plate 23 seals the opening of the cylindrical wall portion 22 on the second direction Z2 side. The tightening portion 22d is tightened to the outer peripheral edge of the sealing plate 23. Alternatively, the sealing plate 23 can be connected to the cylindrical wall portion 22 by welding such as laser welding. The material constituting the sealing plate 23 is not particularly limited, but is formed from aluminum, copper, stainless steel, or the like.

[0060] A through hole 23h is formed in the sealing plate 23. The through hole 23h can be used to inject an electrolyte (not shown) contained in the case 20. The through hole 23h is formed in the center of the sealing plate 23 when viewed in the axial direction Z.

[0061] The sealing plug 24 is inserted into the through hole 23h of the sealing plate 23. Thus, the sealing plug 24 is fixed to the sealing plate 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.

[0062] The external gasket 25 is positioned between the positive electrode terminal 21P and the negative electrode terminal 21N. The external gasket 25 is formed of an insulating material. Thus, 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 disc 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.

[0063] 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. Thus, the internal gasket 26 insulates the wound electrode assembly 10 from the negative electrode terminal 21N. The rivet portion 212 further penetrates the internal gasket 26 in the axial direction Z. Thus, the rivet portion 212 is exposed inside the outer case 20.

[0064] The annular gasket 27 has a circular ring shape. It covers the outer periphery of the sealing plate 23. It is positioned between the outer periphery of the sealing plate 23 and the constricting portion 22d of the cylindrical wall 22. The annular gasket 27 can be formed of either an insulating material or a conductive material. Furthermore, the housing 20 may not include the annular gasket 27.

[0065] In this embodiment, the sealing plate 23 is insulated from the cylindrical wall portion 22 by the annular gasket 27, but the sealing plate 23 may be electrically connected to the cylindrical wall portion 22. In this case, the sealing plate 23 may be a negative electrode terminal.

[0066] In addition, in the present embodiment, the portion of the housing 20 facing the first direction Z1 side is composed of the positive terminal 21P, the negative terminal 21N and the external gasket 25. However, as a part of the above-mentioned portion, the housing 20 may also have a top plate portion. The top plate portion may be located, for example, on the further inner peripheral side of the negative terminal 21N. The top plate portion may be arranged in a manner aligned with the positive terminal 21P in the axial direction Z. The top plate portion may be insulated from the negative terminal 21N. In addition, in the case where the sealing plate 23 becomes the negative terminal as described above, a top plate portion that replaces the negative terminal 21N and is electrically insulated from the sealing plate 23 may also be configured.

[0067] Next, the positive electrode collector plate 30P will be described. Figure 2 、 Figure 3 and Figure 5 As shown, the positive electrode current collector plate 30P is disposed in the case 20. The positive electrode current collector plate 30P is disposed on the first direction Z1 side of the wound electrode body 10.

[0068] The positive electrode current collector plate 30P is provided to electrically connect the positive electrode 11P and the positive electrode terminal 21P. The positive electrode current collector plate 30P is welded to the positive electrode uncoated portion 111PB of the positive electrode 11P. This positively charges the positive electrode current collector plate 30P. The positive electrode current collector plate 30P is welded to the end of the rivet portion 212 of the positive electrode terminal 21P on the second direction Z2 side. This positively charges the positive electrode terminal 21P.

[0069] An internal gasket 26 is placed between the positive current collector plate 30P and the negative terminal 21N. This electrically insulates the positive current collector plate 30P and the negative terminal 21N from each other. Furthermore, the internal gasket 26 extends to the outer periphery of the positive current collector plate 30P. Thus, the internal gasket 26 is also placed between the positive current collector plate 30P and the cylindrical wall portion 22. This electrically insulates the positive current collector plate 30P and the cylindrical wall portion 22 from each other.

[0070] The positive electrode current collector plate 30P has a substantially disk-shaped outer shape and includes a central portion 31P, an outer peripheral edge portion 32P, a plurality of spokes 33P, and a plurality of tabs 35P.

[0071] The central portion 31P 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 positive electrode current collector plate 30P is electrically connected to the positive electrode terminal 21P by connecting the central portion 31P to the outer casing 20. Specifically, the central portion 31P and the rivet portion 212 of the positive electrode terminal 21P are joined by welding.

[0072] The outer peripheral edge portion 32P is provided on the outer periphery of the positive electrode current collector plate 30P. The outer peripheral edge portion 32P is located on the outer periphery of the central portion 31P. The outer peripheral edge portion 32P extends in an annular shape centered on the central portion 31P. The outer peripheral edge portion 32P may also contact the positive electrode uncoated portion 111PB of the positive electrode 11P. However, the outer peripheral edge portion 32P does not bond to the positive electrode uncoated portion 111PB.

[0073] The spokes 33P are spaced apart from one another. The spokes 33P are arranged at equal intervals in the circumferential direction around the central portion 31P. The spokes 33P connect the central portion 31P and the outer peripheral portion 32P. The spokes 33P have an outer shape with a substantially uniform width from the central portion 31P to the outer peripheral portion 32P.

[0074] The plurality of segments 35P are spaced apart from each other. The plurality of segments 35P are arranged at equal intervals in the circumferential direction around the central portion 31P. The plurality of spokes 33P and the plurality of segments 35P are arranged so that the spokes 33P and the segments 35P are alternately arranged in the circumferential direction around the central portion 31P.

[0075] The piece 35P extends from the outer peripheral edge portion 32P toward the central portion 31P. The piece 35P is connected to the positive electrode 11P. Specifically, the piece 35P 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 30P from the joining portion between the sheet portion 35P and the positive electrode uncoated portion 111PB to the joining portion between the central portion 31P and the rivet portion 212 is schematically shown.

[0076] The piece 35P includes a fan-shaped portion 351P and a neck portion 352P. The fan-shaped portion 351P is joined to the positive electrode uncoated portion 111PB of the positive electrode 11P by welding. The tip of the fan-shaped portion 351P faces the central portion 31P. The fan-shaped portion 351P extends toward the outer peripheral edge portion 32P along two adjacent spokes 33P on either side in the circumferential direction. This gives the fan-shaped portion 351P a relatively large surface area, facilitating welding to the positive electrode uncoated portion 111PB of the positive electrode 11P.

[0077] Neck 352P connects outer peripheral edge 32P and fan-shaped portion 351P. Neck 352P may also contact positive electrode uncoated portion 111PB of positive electrode 11P. However, neck 352P does not engage with positive electrode uncoated portion 111PB of positive electrode 11P. The circumferential dimension of neck 352P is smaller than the circumferential dimension of the outer peripheral edge of fan-shaped portion 351P. As a result, sheet 35P is easily flexed at neck 352P.

[0078] Here, an example of a method for welding the central portion 31P to the rivet portion 212 in this embodiment will be described. First, before welding the central portion 31P to the rivet portion 212, the fan-shaped portion 351P of the sheet portion 35P is pre-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, with the welding device abutting the central portion 31P from the second direction Z2 side, the central portion 31P and the rivet portion 212 are welded together by the welding device. At this time, along the path PP, the connection portions between the spokes 33P and the central portion 31P, and the connection portions between the spokes 33P and the outer peripheral portion 32P, significantly flex. This allows the central portion 31P to be easily displaced relative to the sheet portion 35P in the axial direction Z. This prevents the bond between the sheet portion 35P and the positive electrode uncoated portion 111PB from being broken due to displacement of the central portion 31P, even if the welding device abuts against the central portion 31P. Furthermore, the connection between the positive electrode current collector plate 30P and the case 20 is facilitated.

[0079] Next, the negative electrode current collector plate 30N will be described. Figure 7 1 is a top view showing the negative electrode collector plate in Embodiment 1. Figure 2 、 Figure 3 、 Figure 6 and Figure 7 As shown, the negative electrode current collector plate 30N is disposed in the case 20. The negative electrode current collector plate 30N is disposed on one side in the axial direction Z of the wound electrode body 10, that is, on the second direction Z2 side.

[0080] The negative electrode current collector plate 30N is provided to electrically connect the negative electrode 11N and the negative electrode terminal 21N. The negative electrode current collector plate 30N is welded to the negative electrode uncoated portion 111NB of the negative electrode 11N. This imparts a negative charge to the negative electrode current collector plate 30N. The negative electrode current collector plate 30N is joined to the cylindrical wall portion 22 by being tightened together with the outer periphery of the sealing plate 23 and the annular gasket 27 by the tightening portion 22d. This imparts a negative charge to the negative electrode terminal 21N connected to the cylindrical wall portion 22.

[0081] The negative electrode current collector plate 30N has a generally circular outer shape. The negative electrode current collector plate 30N includes a central portion 31N, an outer peripheral portion 32N, a plurality of spokes 33N, a plurality of first sheet portions 34N, and a plurality of second sheet portions 35N. In the first embodiment, the central portion (31), the outer peripheral portion (32), the spokes (33), the first sheet portion (34), and the second sheet portion (35) in the present disclosure are exemplified by the above-mentioned components included in the negative electrode current collector plate 30N.

[0082] The central portion 31N is positioned so as to overlap with the center of the wound electrode body 10 when viewed in the axial direction Z. Specifically, the central portion 31N is located so as to overlap with the winding axis α when viewed in the axial direction Z. The central portion 31N may also contact the negative electrode uncoated portion 111NB of the negative electrode 11N. However, the central portion 31N is not bonded to the negative electrode uncoated portion 111NB.

[0083] A through-hole 31Nh is formed in the central portion 31N. When viewed from the axial direction Z, the through-hole 31N in the central portion 31N overlaps with the through-hole 23h in the sealing plate 23. This facilitates injection of electrolyte through the through-hole 23h. Furthermore, when the pressure within the housing 20 is released, the negative electrode current collector plate 30N is prevented from clogging the through-hole 23h in the sealing plate 23. The sealing plug 24 is also inserted through the through-hole 31Nh in the central portion 31N.

[0084] The outer peripheral edge portion 32N is provided on the outer peripheral edge of the negative electrode current collector plate 30N. The outer peripheral edge portion 32N is located on the outer peripheral side of the central portion 31N. The outer peripheral edge portion 32N extends in an annular shape with the central portion 31P as the center.

[0085] The negative electrode current collector plate 30N is electrically connected to the negative electrode terminal 21N by connecting either the outer peripheral edge portion 32N or the central portion 31N to the outer casing 20. In this embodiment, the negative electrode current collector plate 30N is electrically connected to the negative electrode terminal 21N by connecting the outer peripheral edge portion 32N to the cylindrical wall portion 22. Specifically, the outer peripheral edge portion 32N is joined to the cylindrical wall portion 22 by being tightened by the tightening portion 22d together with the outer peripheral edge of the sealing plate 23 and the annular gasket 27. Thus, the outer peripheral edge portion 32N is electrically connected to the negative electrode terminal 21N connected to the cylindrical wall portion 22.

[0086] The outer peripheral edge portion 32N includes an annular base portion 321 and a plurality of outermost peripheral portions 322. The annular base portion 321 extends annularly with the central portion 31N as the center. The annular base portion 321 is not connected to the cylindrical wall portion 22. In other words, the annular base portion 321 is not clamped to the cylindrical wall portion 22 by the clamping portion 22d.

[0087] The plurality of outermost peripheral portions 322 extend outward from the annular base portion 321. The plurality of outermost peripheral portions 322 are spaced apart from one another. The plurality of outermost peripheral portions 322 are arranged at equal intervals in the circumferential direction centered on the central portion 31P. The plurality of outermost peripheral portions 322 are connected to the cylindrical wall portion 22. In other words, the plurality of outermost peripheral portions 322 are tightened to the cylindrical wall portion 22 by the tightening portion 22d. By tightening and connecting the plurality of spaced-apart outermost portions 322 and the cylindrical wall portion 22, stress concentration acting on the outer peripheral edge portion 32N can be alleviated.

[0088] The spokes 33N are spaced apart from one another. The spokes 33N are arranged at equal intervals in the circumferential direction centered on the central portion 31N. The spokes 33N connect the central portion 31N and the outer peripheral portion 32N. The spokes 33N have an outer shape with a substantially uniform width from the central portion 31N to the outer peripheral portion 32N. The spokes 33N are radially aligned with the outermost portions 322. This prevents shear forces from acting between the annular base 321 and the outermost portion 322 when the spokes 33N flex in the axial direction Z.

[0089] The plurality of first pieces 34N are spaced apart from each other. The plurality of first pieces 34N are arranged at equal intervals in the circumferential direction around the central portion 31N. The plurality of first pieces 34N are adjacent to two spokes 33N on both sides in the circumferential direction.

[0090] The first piece 34N extends from the central portion 31N toward the outer peripheral edge portion 32N. The first piece 34N is connected to the negative electrode 11N. Specifically, the first piece 34N is joined to the negative electrode uncoated portion 111NB of the negative electrode 11N by welding. Figure 6 and Figure 7 The figure schematically illustrates the path on the negative electrode current collector plate 30N, namely the first path PN1, from the junction between the first piece portion 34N and the negative electrode uncoated portion 111NB to the junction between the outer peripheral edge portion 32N and the cylindrical wall portion 22. The first piece portion 34N extends along two adjacent spokes 33N. This provides a relatively large surface area for the first piece portion 34N, facilitating welding to the negative electrode uncoated portion 111NB of the negative electrode 11N.

[0091] The plurality of second segments 35N are spaced apart from one another. The plurality of second segments 35N are arranged at equal intervals in the circumferential direction centered on the central portion 31N. The plurality of second segments 35N are adjacent to two spokes 33N on either side of the circumference. In other words, the first segments 34N and the second segments 35N are arranged in the circumferential direction centered on the central portion 31N, sandwiching the spokes 33N between them.

[0092] The second piece 35N extends from the outer peripheral edge 32N toward the central portion 31N. The second piece 35N is connected to the negative electrode 11N. The second piece 35N and the negative electrode uncoated portion 111NB of the negative electrode 11N are joined by welding. Figure 6 and Figure 7 , schematically illustrates a path on the negative electrode current collector plate 30N, namely, the second path PN2, from the junction between the second sheet portion 35N and the negative electrode uncoated portion 111NB to the junction between the outer peripheral edge portion 32 and the cylindrical wall portion 22. Alternatively, the second sheet portion 35N may not be joined to the negative electrode uncoated portion 111NB by welding.

[0093] The second piece 35N includes a fan-shaped portion 351N and a neck portion 352N. The fan-shaped portion 351N is joined to the negative electrode uncoated portion 111NB of the negative electrode 11N by welding. The tip of the fan-shaped portion 351N faces the central portion 31N. The fan-shaped portion 351N extends along two adjacent spokes 33N on either side of the circumference. This gives the fan-shaped portion 351N a relatively large surface area, facilitating welding to the negative electrode uncoated portion 111NB of the negative electrode 11N.

[0094] The neck portion 352N connects the outer peripheral edge portion 32N and the fan-shaped portion 351N. The neck portion 352N may also contact the negative electrode uncoated portion 111NB of the negative electrode 11N. However, the neck portion 352N does not engage with the negative electrode uncoated portion 111NB of the negative electrode 11N. The circumferential dimension of the neck portion 352N is smaller than the circumferential dimension of the outer peripheral edge of the fan-shaped portion 351N. As a result, the second piece 35N is easily flexed at the neck portion 352N.

[0095] Here, an example of a method for joining the outermost peripheral portion 322 of the outer peripheral edge portion 32N and the cylindrical wall portion 22 by clamping is described. First, before the outermost peripheral portion 322 and the cylindrical wall portion 22 are joined by clamping, the fan-shaped portion 351N of the first piece 34N and the second piece 35N are pre-welded to the negative electrode uncoated portion 111NB of the negative electrode 11N. The cylindrical wall portion 22 is then clamped to form the clamping portion 22d. At this time, along the first path PN1, the connecting portions between the spokes 33N and the central portion 31N, and the connecting portions between the spokes 33N and the outer peripheral edge portion 32N, significantly deflect. This allows the outermost peripheral portion 322 to be easily displaced in the axial direction Z relative to the first piece 34N. This prevents the first sheet portion 34N from breaking its bond with the negative electrode uncoated portion 111NB even if the outer peripheral edge portion 32N is displaced in the axial direction Z when the outer peripheral edge portion 32N is connected to the cylindrical wall portion 22. Furthermore, connection between the negative electrode current collector plate 30N and the case 20 is facilitated.

[0096] On the other hand, the second path PN2 is shorter than the first path PN1. Therefore, when the negative electrode current collector plate 30N is energized, the second path PN2 becomes the main conductive path. The relatively short second path PN2 can reduce heat generation during energization.

[0097] As described above, the storage cell 1 according to the first embodiment of the present disclosure includes a wound electrode body 10, a casing 20, and a current collector plate 30. The wound electrode body 10 includes a first electrode 11A and a second electrode 11B. The casing 20 houses the wound electrode body 10 and includes a first external terminal 21A. The current collector plate 30 is arranged on one side of the wound electrode body 10 in the axial direction Z within the casing 20. The current collector plate 30 is provided to electrically connect the first electrode 11A and the first external terminal 21A. The current collector plate 30 includes a central portion 31, an outer peripheral portion 32, spokes 33, a first sheet portion 34, and a second sheet portion 35. The central portion 31 is arranged so as to overlap with the center of the wound electrode body 10 when viewed from the axial direction Z. The outer peripheral portion 32 is located on the outer peripheral side of the central portion 31. The current collector plate 30 is electrically connected to the first external terminal 21A by connecting either the outer peripheral portion 32 or the central portion 31 to the casing 20. Spokes 33 connect central portion 31 and outer peripheral portion 32. First piece 34 extends from central portion 31 toward outer peripheral portion 32 and is connected to first electrode 11A. Second piece 35 extends from outer peripheral portion 32 toward central portion 31 and is connected to first electrode 11A.

[0098] According to the above configuration, the connection between the current collector plate 30 and the case 20 becomes easy, and heat generation of the current collector plate 30 can be suppressed.

[0099] Furthermore, from another perspective, the above-described configuration allows the storage cell 1 to generate moderate heat when energized. For example, as in the first embodiment of the present disclosure, when the outer peripheral portion 32 is connected to the housing 20, the path PN1 on the current collector plate 30, which is connected in the order of the first sheet 34, the central portion 31, the spokes 33, and the outer peripheral portion 32, is relatively long. Consequently, when energized, the current collector plate 30 generates relatively large amounts of heat along this path PN1. On the other hand, the path on the current collector plate 30 consisting only of the second sheet 35 and the outer peripheral portion 32 is relatively short. Consequently, the heat generated along this path PN2 when energized is relatively small. Thus, a storage cell 1 capable of generating moderate heat when energized can be provided.

[0100] Furthermore, in the first embodiment of the present disclosure, the first piece portion 34 and the second piece portion 35 are arranged with the spoke 33 interposed therebetween in the circumferential direction around the central portion 31 .

[0101] With the above configuration, the long conductive paths (first paths PN1 in this embodiment) on the current collector plate 30, which generate relatively high amounts of heat when current is applied, and the short conductive paths (second paths PN2 in this embodiment) on the current collector plate 30, which generate relatively low amounts of heat, are arranged circumferentially. This reduces circumferential variations in the distribution of heat generated by the current collector plate 30 when current is applied.

[0102] Furthermore, in the first embodiment of the present disclosure, the first piece portion 34 and the second piece portion 35 are welded to the first electrode 11A.

[0103] With the above-described configuration, the first sheet portion 34 and the second sheet portion 35 are securely connected by the first electrode 11A. Furthermore, the conductive path (first path PN1 in this embodiment) and the conductive path (second path PN2 in this embodiment) through the first sheet portion 34 and through the second sheet portion 35 in the current collector plate 30 are more securely formed.

[0104] Furthermore, in the first embodiment of the present disclosure, the case 20 includes the cylindrical wall portion 22 that entirely covers the outer periphery of the wound electrode body 10. The outer peripheral edge portion 32 is connected to the cylindrical wall portion 22, thereby electrically connecting the current collector plate 30 to the first external terminal 21A.

[0105] According to the above configuration, the conductive path from the current collector plate 30 to the first external terminal 21A includes the relatively large outer surface area of ​​the cylindrical wall portion 22. This allows heat generated in the conductive path during current flow to be easily dissipated from the outer surface of the cylindrical wall portion 22.

[0106] (Implementation Method 2)

[0107] Next, the power storage cell according to the second embodiment of the present disclosure will be described. In the second embodiment of the present disclosure, the configuration of the first and second sheets of the negative electrode current collector plates differs from that of the first embodiment of the present disclosure. Therefore, the configuration and effects similar to those of the first embodiment of the present disclosure will not be repeated.

[0108] Figure 8 This is a cross-sectional view showing a power storage unit according to the second embodiment. Figure 9 This is a plan view showing a negative electrode current collector plate in the second embodiment.

[0109] like Figure 8 and Figure 9 As shown, in the electricity storage cell 1 a according to the second embodiment of the present disclosure, the first sheet portion 34 a and the second sheet portion 35 a are arranged in the radial direction centered on the central portion 31 .

[0110] According to the above configuration, the first sheet portion 34a and the second sheet portion 35a can be arranged compactly. Thus, for example, the number of the first sheet portion 34a and the number of the second sheet portion 35a are increased compared to the first embodiment.

[0111] The spokes 33 and the first pieces 34a are arranged alternately in the circumferential direction around the center portion 31. The spokes 33 and the second pieces 35a are arranged alternately in the circumferential direction around the center portion 31.

[0112] (Implementation 3)

[0113] Next, the power storage unit according to the third embodiment of the present disclosure will be described. The third embodiment of the present disclosure differs primarily from the first embodiment of the present disclosure in that the current collector plate is exemplified by a positive electrode current collector plate 30P. Therefore, the same configuration and effects as those of the third embodiment of the present disclosure will not be repeated.

[0114] Figure 10 This is a cross-sectional view of a power storage unit according to the third embodiment. Figure 11 This is another cross-sectional view of the power storage unit according to the third embodiment. Figure 12 This is an exploded perspective view showing the power storage unit according to the third embodiment. Figure 13 This is another exploded perspective view showing the power storage unit according to the third embodiment.

[0115] like Figures 10 to 13 As shown, in the power storage unit 1b according to the third embodiment of the present disclosure, the positive electrode 11Pb is exemplified as the first electrode (11Ab) in the present disclosure, and the negative electrode 11Nb is exemplified as the second electrode (11Ab) in the present disclosure. Furthermore, the positive electrode terminal 21Pb is exemplified as the first external terminal (21Ab) in the present disclosure, and the negative electrode terminal 21Nb is exemplified as the second external terminal (21Bb) in the present disclosure.

[0116] First, the positive electrode current collecting plate 30Pb in this embodiment will be described. Figure 14 : is a top view showing the positive electrode collector plate in Embodiment 3. Figures 10 to 12 and Figure 14 As shown, as the current collector plate (30b) in the present disclosure, the positive electrode current collector plate 30Pb is exemplified. As the central portion (31), the outer peripheral portion (32), the spokes (33), the first sheet portion (34b), and the second sheet portion (35b) in the present disclosure, the central portion (31P), the outer peripheral portion (32P), the spokes (33P), the first sheet portion (34Pb), and the second sheet portion (35Pb) included in the positive electrode current collector plate 30P are exemplified respectively.

[0117] In the third embodiment, the positive electrode current collecting plate 30P includes a plurality of first sheet portions 34Pb and a plurality of second sheet portions 35Pb.

[0118] The plurality of first pieces 34Pb are spaced apart from each other. The plurality of first pieces 34Pb are arranged at equal intervals in the circumferential direction around the central portion 31P. The plurality of first pieces 34Pb are adjacent to two spokes 33P on both sides in the circumferential direction.

[0119] The first piece portion 34Pb extends from the central portion 31P toward the outer peripheral edge portion 32P. The first piece portion 34Pb is connected to the positive electrode 11P. Specifically, the first piece portion 34Pb is joined to the positive electrode uncoated portion 111PB of the positive electrode 11P by welding. Figure 14 , schematically illustrates the path on the positive electrode current collector plate 30Pb, namely the first path PP1b, from the junction between the first sheet portion 34Pb and the positive electrode uncoated portion 111PB to the junction between the central portion 31P and the rivet portion 212. The first sheet portion 34Pb extends along two adjacent spokes 33P. This provides a relatively large surface area for the first sheet portion 34Pb, facilitating welding to the positive electrode uncoated portion 111PB of the positive electrode 11P. Alternatively, the first sheet portion 34Pb may be joined to the positive electrode uncoated portion 111PB without welding.

[0120] The plurality of second pieces 35Pb are spaced apart from one another. The plurality of second pieces 35Pb are arranged at equal intervals in the circumferential direction centered on the central portion 31P. Each of the plurality of second pieces 35Pb is adjacent to two spokes 33P on either side of the circumference. In other words, the first piece 34Pb and the second piece 35Pb are arranged in the circumferential direction centered on the central portion 31P, sandwiching the spokes 33P between them.

[0121] The second piece 35Pb extends from the outer peripheral edge portion 32P toward the central portion 31P. The second piece 35Pb is connected to the positive electrode 11P. The second piece 35Pb is joined to the positive electrode uncoated portion 111PB of the positive electrode 11P by welding. Figure 14 , a path on the positive electrode current collector plate 30P from the joining portion between the second sheet portion 35Pb and the positive electrode uncoated portion 111PB to the joining portion between the central portion 31P and the rivet portion 212 , that is, the second path PP2b is schematically shown.

[0122] The second piece 35Pb includes a fan-shaped portion 351P and a neck portion 352P. The fan-shaped portion 351P is joined to the positive electrode uncoated portion 111PB of the positive electrode 11P by welding. The tip of the fan-shaped portion 351P faces the central portion 31P. The fan-shaped portion 351P extends along two adjacent spokes 33P on either side of the circumference. This gives the fan-shaped portion 351P a relatively large surface area, facilitating welding to the positive electrode uncoated portion 111PB of the positive electrode 11P.

[0123] The neck portion 352P connects the outer peripheral edge portion 32P and the fan-shaped portion 351P. The neck portion 352P may also contact the positive electrode uncoated portion 111PB of the positive electrode 11P. However, the neck portion 352P does not engage with the positive electrode uncoated portion 111PB of the positive electrode 11P. The circumferential dimension of the neck portion 352P is smaller than the circumferential dimension of the outer peripheral edge of the fan-shaped portion 351P. As a result, the second piece 35Pb is easily flexed at the neck portion 352P.

[0124] Here, an example of a method for welding the central portion 31P to the rivet portion 212 in this embodiment will be described. First, before welding the central portion 31P to the rivet portion 212, the fan-shaped portions 351P of the first and second sheet portions 34Pb, 35Pb, are pre-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. With the welding device positioned against the central portion 31P from the second direction Z2 side, the central portion 31P and the rivet portion 212 are welded together by the welding device. At this time, along the second path PP2b, the connection portions between the spokes 33P and the central portion 31P, and between the spokes 33P and the outer peripheral portion 32P, significantly flex. This allows the central portion 31P to easily displace relative to the second sheet portion 35Pb in the axial direction Z. This prevents the second sheet portion 35Pb and the positive electrode uncoated portion 111PB from being broken due to displacement of the central portion 31P, even if the welding device abuts against the central portion 31P. Furthermore, the positive electrode current collector plate 30Pb and the case 20 are easily connected.

[0125] On the other hand, the first path PP1b is shorter than the second path PP2b. Therefore, when the positive electrode current collecting plate 30Pb is energized, the first path PP1b becomes the main conductive path. The relatively short first path PP1b can reduce heat generation during energization.

[0126] Next, the negative electrode current collector plate 30Nb in the third embodiment will be described. Figure 10 、 Figure 11 and Figure 13 As shown, in the third embodiment, the negative electrode current collector plate 30Nb includes a plurality of tab portions 34Nb.

[0127] The plurality of segments 34Nb are spaced apart from each other. The plurality of segments 34Nb are arranged at equal intervals in the circumferential direction centered on the central portion 31N. The plurality of spokes 33N and the plurality of segments 34Nb are arranged so that the spokes 33N and the segments 34Nb are alternately arranged in the circumferential direction centered on the central portion 31N.

[0128] The piece 34Nb extends from the central portion 31N toward the outer peripheral edge portion 32N. The piece 34Nb is connected to the negative electrode 11N. Specifically, the piece 34Nb is joined to the negative electrode uncoated portion 111NB of the negative electrode 11N by welding. Figure 13The figure schematically illustrates the path PNb on the negative electrode current collector plate 30N, from the junction between the tab portion 34Nb and the negative electrode uncoated portion 111NB to the junction between the outer peripheral edge portion 32N and the cylindrical wall portion 22. The tab portion 34Nb extends along two adjacent spokes 33N. This gives the tab portion 34Nb a relatively large surface area, facilitating welding to the negative electrode uncoated portion 111NB of the negative electrode 11N.

[0129] Here, an example of a method for joining the outermost peripheral portion 322 of the outer peripheral edge portion 32N to the cylindrical wall portion 22 by clamping will be described. First, before the outermost peripheral portion 322 and the cylindrical wall portion 22 are joined by clamping, the tab portion 34Nb is pre-welded to the negative electrode uncoated portion 111NB of the negative electrode 11N. The cylindrical wall portion 22 is then clamped, forming the clamping portion 22d. At this time, along the path PNb, the connecting portions of the spokes 33N and the central portion 31N, as well as the connecting portions of the spokes 33N and the outer peripheral edge portion 32N, significantly flex. This allows the outermost peripheral portion 322 to be easily displaced in the axial direction Z relative to the tab portion 34Nb. Consequently, even if the outer peripheral edge portion 32N displaces in the axial direction Z during connection to the cylindrical wall portion 22, the connection between the tab portion 34Nb and the negative electrode uncoated portion 111NB is prevented from being broken. Furthermore, the connection between the negative electrode current collector plate 30Nb and the outer case 20 becomes easy.

[0130] As described above, the storage cell 1b according to the third embodiment of the present disclosure includes a wound electrode body 10, a casing 20, and a collector plate 30b. The wound electrode body 10 includes a first electrode 11Ab and a second electrode 11B. The casing 20 houses the wound electrode body 10 and includes a first external terminal 21Ab. The collector plate 30b is arranged on one side of the wound electrode body 10 in the axial direction Z within the casing 20. The collector plate 30b is provided to electrically connect the first electrode 11Ab and the first external terminal 21Ab. The collector plate 30b includes a central portion 31, an outer peripheral portion 32, spokes 33, a first sheet portion 34b, and a second sheet portion 35b. The central portion 31 is arranged so as to overlap with the center of the wound electrode body 10 when viewed from the axial direction Z. The outer peripheral portion 32 is located on the outer peripheral side of the central portion 31. The current collector plate 30b is electrically connected to the first external terminal 21Ab via either the outer peripheral portion 32 or the central portion 31 connected to the housing 20. The spokes 33 connect the central portion 31 and the outer peripheral portion 32. The first piece 34b extends from the central portion 31 toward the outer peripheral portion 32 and is connected to the first electrode 11Ab. The second piece 35b extends from the outer peripheral portion 32 toward the central portion 31 and is connected to the first electrode 11Ab.

[0131] According to the above configuration, the connection between the current collector plate 30 b and the case 20 becomes easy, and heat generation of the current collector plate 30 b can be suppressed.

[0132] From another perspective, the above-described configuration allows the power storage cell 1b to generate moderate heat when power is supplied. For example, as in Embodiment 3 of the present disclosure, when the central portion 31 is connected to the housing 20, the path PP2b on the current collector plate 30b, which connects the second sheet portion 35b, the outer peripheral portion 32, the spokes 33, and the central portion 31 in this order, is relatively long. Consequently, when power is supplied to the power storage cell 1b, the current collector plate 30b generates relatively high heat along this path PP2b. On the other hand, the path PP1b on the current collector plate 30b, which consists solely of the first sheet portion 34b and the central portion 31, is relatively short. Consequently, heat generated along this path PP1b during power supply is relatively low. This provides a power storage cell 1b that generates moderate heat during power supply.

[0133] Furthermore, in the third embodiment of the present disclosure, the first piece portion 34 b and the second piece portion 35 b are arranged with the spoke 33 interposed therebetween in the circumferential direction around the central portion 31 .

[0134] With the above configuration, the long conductive paths (second paths PP2b in this embodiment) on the current collector plate 30b, which generate relatively high amounts of heat when current is applied, and the short conductive paths (first paths PP1b in this embodiment) on the current collector plate 30b, which generate relatively low amounts of heat, are aligned circumferentially. This reduces circumferential variations in the distribution of heat generated by the current collector plate 30b when current is applied.

[0135] Furthermore, in the third embodiment of the present disclosure, the first piece portion 34 b and the second piece portion 35 b are welded to the first electrode 11Ab.

[0136] With the above-described configuration, the first sheet portion 34b and the second sheet portion 35b are securely fixedly connected by the first electrode 11Ab. Furthermore, the conductive path (first path PP1b in this embodiment) and the conductive path (second path PP2b in this embodiment) through the first sheet portion 34b and through the second sheet portion 35b in the current collector plate 30b are more securely formed.

[0137] Furthermore, in the third embodiment of the present disclosure, the first external terminal 21Ab is located at a position overlapping the central portion 31 when viewed in the axial direction Z. Furthermore, the central portion 31 is connected to the case 20 , and the current collector plate 30b is electrically connected to the first external terminal 21Ab.

[0138] According to the above-described configuration, the conductive path from the current collector plate 30 b to the first external terminal 21Ab can be shortened, and heat generation in the conductive path can be suppressed.

[0139] (Implementation 4)

[0140] Next, the power storage cell according to the fourth embodiment of the present disclosure will be described. In the fourth embodiment of the present disclosure, the first and second sheets of the positive electrode current collector plate differ from those in the third embodiment of the present disclosure. Therefore, the same configuration and effects as in the third embodiment of the present disclosure will not be repeated.

[0141] Figure 15 This is a cross-sectional view showing a power storage unit according to the fourth embodiment. Figure 16 This is a plan view showing a positive electrode current collecting plate in the fourth embodiment.

[0142] like Figure 15 and Figure 16 As shown, in the electricity storage cell 1 c according to the fourth embodiment of the present disclosure, the first sheet portion 34 c and the second sheet portion 35 c are arranged in the radial direction centered on the central portion 31 .

[0143] According to the above configuration, the first sheet portion 34c and the second sheet portion 35c can be arranged compactly. Thus, for example, the number of the first sheet portion 34c and the number of the second sheet portion 35c are increased compared to the third embodiment.

[0144] The spokes 33 and the first pieces 34 c are arranged alternately in the circumferential direction around the center portion 31. The spokes 33 and the second pieces 35 c are arranged alternately in the circumferential direction around the center portion 31.

[0145] (Implementation 5)

[0146] Next, the power storage cell according to the fifth embodiment of the present disclosure will be described. The fifth embodiment of the present disclosure differs from the power storage cell 1b according to the third embodiment of the present disclosure in that it does not include a negative electrode current collector plate. Therefore, the same configuration and effects as those of the third embodiment of the present disclosure will not be repeated.

[0147] Figure 17 This is a cross-sectional view of a power storage unit according to the fifth embodiment. Figure 18 This is an exploded perspective view showing the power storage unit according to the fifth embodiment in an exploded manner.

[0148] like Figure 17 and Figure 18 As shown, in the power storage unit 1d according to the fifth embodiment, the casing 20 does not include an annular gasket.

[0149] The outer peripheral edge of the sealing plate 23d in this embodiment is connected to the cylindrical wall portion 22 by welding such as laser welding. Therefore, in this embodiment, the cylindrical wall portion 22 is not provided with a tightening portion.

[0150] In this embodiment, the sealing plate 23d is provided to electrically connect the negative electrode 11N and the negative electrode terminal 21N. The sealing plate 23d is welded to the negative electrode uncoated portion 111NB of the negative electrode 11N. This causes the sealing plate 23d to be negatively charged. Furthermore, the negative electrode terminal 21N connected to the cylindrical wall portion 22 is negatively charged. Alternatively, the sealing plate 23d may serve as the negative electrode terminal.

[0151] The sealing plate 23d includes an annular ridge 231, multiple radial ridges 232, and multiple welds 233. The annular ridge 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 231 protrudes toward the first direction Z1. That is, the annular ridge 231 protrudes toward the wound electrode body 10. The annular ridge 231 contacts the negative electrode uncoated portion 111NB of the negative electrode 11N.

[0152] 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.

[0153] The plurality of radial ridges 232 extend 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 .

[0154] 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.

[0155] The multiple welds 233 are portions of the sealing plate 23d that are welded to the negative electrode uncoated portion 111NB. The multiple welds 233 are formed on the annular ridge 231. In the annular ridge 231, the multiple welds 233 are formed to extend circumferentially. The multiple welds 233 are formed on each of the multiple radial ridges 232. In the radial ridges 232, the welds 233 are formed to extend radially. The annular ridge 231 and the multiple radial ridges 232 can be thinner than other portions of the sealing plate 23d. This facilitates the formation of the welds 233.

[0156] In the above description of the embodiments, it is also possible to combine mutually combinable configurations. For example, it is possible to combine a positive electrode current collector plate in one embodiment with a negative electrode current collector plate in another embodiment.

[0157] While the embodiments of the present invention have been described, the embodiments disclosed herein are intended to be illustrative in all respects and not restrictive. The scope of the present invention is indicated by the claims, and is intended to encompass all modifications within the meaning and scope equivalent to the claims.

Claims

1. A power storage unit, characterized in that: have: A wound electrode body comprising a first electrode and a second electrode; a housing for housing the wound electrode assembly and comprising a first external terminal; and a current collector plate disposed on one side of the wound electrode body in the axial direction within the casing and provided to electrically connect the first electrode and the first external terminal; The current collector plate includes a central portion, an outer peripheral portion, spokes, a first sheet portion, and a second sheet portion. The central portion is arranged so as to overlap with the center of the wound electrode body when viewed from the axial direction. The outer peripheral edge portion is located on the outer peripheral side of the central portion, The collector plate is electrically connected to the first external terminal via either the outer peripheral portion or the central portion connected to the housing. The spokes connect the central portion and the outer peripheral portion. The first piece extends from the central portion toward the outer peripheral edge portion and is connected to the first electrode. The second piece portion extends from the outer peripheral portion toward the central portion and is connected to the first electrode.

2. The power storage unit according to claim 1, wherein The first piece portion and the second piece portion are arranged with the spokes interposed therebetween in a circumferential direction centered on the central portion.

3. The power storage unit according to claim 1, wherein The first piece portion and the second piece portion are arranged in a radial direction centered on the central portion.

4. The power storage unit according to claim 1, wherein The first piece portion and the second piece portion are welded to the first electrode.

5. The power storage unit according to any one of claims 1 to 4, characterized in that The outer shell includes a cylindrical wall portion covering the entire outer circumference of the wound electrode body. The outer peripheral edge portion is connected to the cylindrical wall portion, so that the current collector plate is electrically connected to the first external terminal.

6. The power storage unit according to any one of claims 1 to 4, characterized in that The first external terminal is located at a position overlapping with the central portion when viewed from the axial direction. The central portion is connected to the housing, and the current collector plate is electrically connected to the first external terminal.

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