Energy storage cell

Abstract

To provide a power storage cell capable of generating heat appropriately when energized. [Solution] In a storage cell (1) according to the present disclosure, a current collector (30) includes a central portion (31), an outer peripheral edge portion (32), spokes (33), a first arm portion (34), and a second arm portion (35). The central portion (31) is disposed so as to overlap the center of the wound electrode body (10) when viewed from the axial direction (Z). The outer peripheral edge portion (32) is located on the outer peripheral side of the central portion (31). Either the outer peripheral edge portion (32) or the central portion (31) is connected to the case (20), thereby electrically connecting the current collector (30) to a first external terminal (21A). The spokes (33) connect the central portion (31) and the outer peripheral edge portion (32). The first arm portion (34) extends from the central portion (31) toward the outer peripheral edge portion (32) and is connected to the first electrode (11A). The second arm portion (35) extends from the outer peripheral edge portion (32) toward the central portion (31) and is connected to the first electrode (11A).

Description

[Technical Field]

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

[0002] Patent Document 1 discloses a cylindrical battery in which an electrode group consisting of a positive electrode, a negative electrode, and a separator is spirally wound and housed in a battery case. The battery uses a tabless method for connecting the positive electrode lead. The lead attached to the current collector of the positive electrode is welded to the back of the lid. The overlapping lead of the negative electrode is spot-welded to the bottom of the case. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 3324372 Summary of the Invention [Problem to be solved by the invention]

[0004] Energy storage cells such as the cylindrical battery disclosed in Patent Document 1 may be charged by rapid charging. When the energy storage cells are rapid charged, it is preferable that the temperature of the energy storage cells is elevated to a certain extent. However, in order to maintain the functionality of the energy storage cells, excessive heat generation in the energy storage cells needs to be suppressed.

[0005] The present disclosure has been made in consideration of the above-mentioned problems, and has an object to provide an electricity storage cell that can generate heat appropriately when energized. [Means for solving the problem]

[0006] An energy storage cell according to the present disclosure includes a wound electrode assembly, a case, and a current collector plate. The wound electrode assembly includes a first electrode and a second electrode. The case houses the wound electrode assembly and includes a first external terminal. The current collector plate is disposed within the case on one axial side of the wound electrode assembly. The current collector plate is provided to electrically connect the first electrode and the first external terminal. The current collector plate includes a central portion, an outer peripheral edge portion, spokes, a first arm portion, and a second arm portion. The central portion is disposed so as to overlap with the center of the wound electrode assembly when viewed from the axial direction. The outer peripheral edge portion is located on the outer peripheral side of the central portion. Either the outer peripheral edge portion or the central portion is connected to the case, thereby electrically connecting the current collector plate to the first external terminal. The spoke connects the central portion and the outer peripheral edge portion. The first arm portion extends from the central portion toward the outer peripheral edge portion and is connected to the first electrode. The second piece extends from the outer periphery toward the center and is connected to the first electrode.

[0007] In the above configuration, first, for example, when the outer peripheral edge portion is connected to the case, the path on the current collector plate, which is connected in this order from the first arm portion, the central portion, the spokes, and the outer peripheral edge portion, is relatively long. Therefore, when the energy storage cell is energized, the current collector plate generates a relatively large amount of heat along this path. On the other hand, the path on the current collector plate, which is composed only of the second arm portion and the outer peripheral edge portion, is relatively short. Therefore, heat generation along this path during energization is relatively small. This makes it possible to provide an energy storage cell that can generate a moderate amount of heat when energized. Second, for example, when the central portion is connected to the case, the path on the current collector plate, which is connected in this order from the second arm portion, the outer peripheral edge portion, the spokes, and the central portion, is relatively long. Therefore, when the energy storage cell is energized, the current collector plate generates a relatively large amount of heat along this path. On the other hand, the path on the current collector plate, which is composed only of the first arm portion and the central portion, is relatively short. Therefore, heat generation along this path during energization is relatively small. This makes it possible to provide an energy storage cell that can generate a moderate amount of heat when energized.

[0008] In the energy storage cell according to the present disclosure, the first arm and the second arm are preferably arranged side by side via spokes in the circumferential direction centered on the central portion.

[0009] According to the above configuration, the long paths on the current collector plate where heat generation is relatively large when current is applied and the short paths on the current collector plate where heat generation is relatively small are aligned in the circumferential direction, thereby reducing the uneven distribution of the heat generation amount when current is applied to the current collector plate in the circumferential direction.

[0010] In the energy storage cell according to the present disclosure, the first and second arms are preferably aligned in a radial direction centered on the central portion, allowing the first and second arms to be arranged compactly.

[0011] In the energy storage cell according to the present disclosure, the first arm and the second arm are preferably welded to the first electrode 11A.

[0012] According to the above configuration, the first arm and the second arm are reliably fixedly connected to the first electrode, which in turn more reliably forms a conductive path in the current collector plate passing through the first arm and the second arm.

[0013] In the energy storage cell according to the present disclosure, the case preferably includes a cylindrical wall portion that covers the entire outer periphery of the wound electrode body, and the outer periphery is connected to the cylindrical wall portion, thereby electrically connecting the current collector plate to the first external terminal.

[0014] According to the above configuration, the conductive path from the current collecting plate to the first external terminal includes a cylindrical wall portion having a relatively large outer surface area, and therefore, heat generated when electricity is passed through the conductive path can be easily dissipated from the outer surface of the cylindrical wall portion.

[0015] In the energy storage cell according to the present disclosure, the first external terminal is preferably positioned so as to overlap with the central portion when viewed in the axial direction, and the current collector plate is electrically connected to the first external terminal by connecting the central portion to the case.

[0016] 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. [Effects of the Invention]

[0017] According to the present disclosure, it is possible to provide an electricity storage cell that can generate heat appropriately when energized. [Brief explanation of the drawings]

[0018] [Figure 1] 1 is a perspective view showing a storage cell according to a first embodiment. [Figure 2] 2 is a cross-sectional view of the storage cell of FIG. 1 as viewed in the direction of the arrows along line II-II. [Figure 3] 3 is a cross-sectional view of the storage cell of FIG. 1 as viewed in the direction of the arrows along line III-III. [Figure 4] FIG. 2 is a partially exploded perspective view of a wound electrode body. [Figure 5] 1 is an exploded perspective view showing an energy storage cell according to a first embodiment. FIG. [Figure 6] FIG. 4 is another exploded perspective view showing the energy storage cell according to the first embodiment. [Figure 7] FIG. 2 is a plan view showing a negative electrode current collector plate in the first embodiment. [Figure 8] FIG. 4 is a cross-sectional view showing a storage cell according to a second embodiment. [Figure 9] FIG. 10 is a plan view showing a negative electrode current collector plate in the second embodiment. [Figure 10] FIG. 10 is a cross-sectional view of a storage cell according to a third embodiment. [Figure 11] FIG. 10 is another cross-sectional view of the energy storage cell according to the third embodiment. [Figure 12] FIG. 10 is an exploded perspective view showing an electricity storage cell according to a third embodiment. [Figure 13] FIG. 10 is another exploded perspective view showing the energy storage cell according to the third embodiment. [Figure 14] FIG. 10 is a plan view showing a positive electrode current collector plate in a third embodiment. [Figure 15] FIG. 10 is a plan view showing a storage cell according to a fourth embodiment. [Figure 16] FIG. 10 is a plan view showing a positive electrode current collector plate in Embodiment 4. [Figure 17] FIG. 10 is a cross-sectional view of a storage cell according to a fifth embodiment. [Figure 18] FIG. 10 is an exploded perspective view showing an energy storage cell according to a fifth embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0019] Hereinafter, a description will be given of a storage cell according to each embodiment of the present disclosure with reference to the drawings. The same or corresponding parts in the drawings are denoted by the same reference numerals, and the description thereof will not be repeated.

[0020] (Embodiment 1) Fig. 1 is a perspective view showing a storage cell according to embodiment 1. Fig. 2 is a cross-sectional view of the storage cell of Fig. 1 as seen in the direction of the arrows II-II. Fig. 3 is a cross-sectional view of the storage cell of Fig. 1 as seen in the direction of the arrows III-III.

[0021] 1 to 3, the energy storage cell 1 is a cylindrical battery. The energy storage cell 1 includes a wound electrode assembly 10, a case 20, a positive electrode current collector plate 30P, and a negative electrode current collector plate 30N. In the first embodiment, the negative electrode current collector plate 30N is exemplified as the current collector plate (30) in the present disclosure.

[0022] First, the wound electrode body 10 will be described. Fig. 4 is a perspective view showing a partially exploded wound electrode body. As shown in Figs. 2 to 4, the wound electrode body 10 is wound to form a cylindrical shape. Fig. 4 shows the wound electrode body 10 in a slightly unwound state.

[0023] The wound electrode body 10 includes a positive electrode 11P, a negative electrode 11N, and a separator 12. In the wound electrode body 10, the positive electrode 11P, the negative electrode 11N, and the separator 12 are wound around the periphery of the winding axis α. In the first embodiment, the negative electrode 11N is exemplified as the first electrode (11A) of the present disclosure, and the positive electrode 11P is exemplified as the second electrode (11B).

[0024] Positive electrode 11P and negative electrode 11N have a sheet-like outer shape. Wound electrode body 10 is composed of an electrode plate group in which positive electrode 11P and negative electrode 11N are wound with separator 12 interposed therebetween.

[0025] Separator 12 is provided between positive electrode 11P and negative electrode 11N. Separator 12 separates positive electrode 11P from negative electrode 11N while allowing ions (e.g., lithium ions) to move between positive electrode 11P (positive electrode active material) and negative electrode 11N (negative electrode active material).

[0026] Positive electrode 11P includes positive electrode current collector 111P and positive electrode composite material layer 112P. Positive electrode current collector 111P is made of, for example, aluminum.

[0027] The positive electrode mixture layer 112P is applied to both radial surfaces of the positive electrode current collector 111P (a positive electrode coated portion 111PA described later). The positive electrode mixture layer 112P is in close contact with the separator 12. The positive electrode mixture layer 112P is formed by applying a positive electrode slurry to the surface of the positive electrode current collector 111P and drying the coating. The positive electrode slurry is prepared by kneading the materials for the positive electrode mixture layer 112P (such as a positive electrode active material and a binder) with a solvent. The thickness of the positive electrode mixture layer 112P is, for example, 0.1 μm or more and 1000 μm or less.

[0028] Positive electrode current collector 111P includes positive electrode coated portion 111PA and positive electrode uncoated portion 111PB. Positive electrode coated portion 111PA is a portion of positive electrode current collector 111P that is coated with positive electrode composite material layer 112P. In other words, positive electrode coated portion 111PA is a portion that is not exposed because it is covered with positive electrode composite material layer 112P.

[0029] The positive electrode uncoated portion 111PB is an exposed portion of the positive electrode current collector 111P that is not covered by the positive electrode composite 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.

[0030] The positive electrode uncoated portion 111PB includes a plurality of extending portions 111PC. The extending portions 111PC are arranged in the winding direction of the wound electrode body 10.

[0031] Negative electrode 11N includes negative electrode current collector 111N and negative electrode composite material layer 112N. Negative electrode current collector 111N is made of, for example, copper.

[0032] The negative electrode mixture layer 112N is applied to both radial surfaces of the negative electrode current collector 111N (negative electrode coated portion 111NA described later). The negative electrode mixture layer 112N is in close contact with the separator 12. The negative electrode mixture layer 112N is formed by applying a negative electrode slurry to the surface of the negative electrode current collector 111N and drying the coating. The negative electrode slurry is prepared by kneading the materials for 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, 0.1 μm or more and 1000 μm or less.

[0033] Negative electrode current collector 111N includes a negative electrode coated portion 111NA and a negative electrode uncoated portion 111NB. Negative electrode coated portion 111NA is a portion of negative electrode current collector 111N that is coated with negative electrode composite material layer 112N. In other words, negative electrode coated portion 111NA is a portion that is not exposed because it is covered with negative electrode composite material layer 112N.

[0034] The negative electrode uncoated portion 111NB is an 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 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 in the second direction Z2 along the axial direction Z. The negative electrode uncoated portion 111NB is bent radially inward.

[0035] The negative electrode uncoated portion 111NB includes a plurality of extending portions 111NC. The extending portions 111NC are arranged in the winding direction of the wound electrode body 10.

[0036] Next, the case 20 will be described. Fig. 5 is an exploded perspective view showing the energy storage cell according to embodiment 1. Fig. 6 is another exploded perspective view showing the energy storage cell according to embodiment 1.

[0037] 1 to 3, 5, and 6, 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.

[0038] 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 located approximately on the winding axis α of the wound electrode body 10. The rivet portion 212 extends in the second direction Z2. The positive electrode terminal 21P is formed of, for example, aluminum.

[0039] The negative electrode terminal 21N is disposed so as to be perpendicular to the axial direction Z. A through hole 21Nh is provided in the negative electrode terminal 21N. Therefore, the negative electrode terminal 21N has an annular outer shape when viewed from the axial direction Z. The negative electrode terminal 21N is positioned between the disk portion 211 and the wound electrode body 10 in the axial direction Z. The rivet portion 212 is inserted into the through hole 21Nh. The rivet portion 212 extends to the inside of the case 20. The material constituting the negative electrode terminal 21N is not particularly limited, but is formed from aluminum, copper, stainless steel, or the like.

[0040] The cylindrical wall portion 22 is provided on the outer circumferential side of the wound electrode body 10. The cylindrical wall portion 22 covers the entire outer circumferential side of the wound electrode body 10. The cylindrical wall portion 22 has a cylindrical shape. 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 formed integrally with the negative electrode terminal 21N. There are no particular limitations on the material that constitutes the cylindrical wall portion 22, but it is formed from aluminum, copper, stainless steel, or the like.

[0041] A crimped portion 22d is formed at the end portion on the second direction Z2 side of the cylindrical wall portion 22. The crimped portion 22d is formed in an annular shape along the circumferential direction of the wound electrode body 10. Note that Figures 5 and 6 show the cylindrical wall portion 22 in a state before the crimped portion 22d is formed.

[0042] The sealing plate 23 is connected to the end 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 crimping portion 22d is crimped to the outer periphery of the sealing plate 23. The sealing plate 23 may 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 it is formed of aluminum, copper, stainless steel, or the like.

[0043] A through hole 23h is formed in the sealing plate 23. The through hole 23h may be used to inject an electrolyte (not shown) to be contained in the case 20. The through hole 23h is formed in the center of the sealing plate 23 when viewed from the axial direction Z.

[0044] The sealing plug 24 is inserted into the through-hole 23h of the sealing plate 23. This fixes the sealing plug 24 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 case 20 when the pressure inside the case 20 becomes excessively high.

[0045] The external gasket 25 is disposed between the positive electrode terminal 21P and the negative electrode terminal 21N. The external gasket 25 is formed of an insulating material. Therefore, the external gasket 25 insulates the positive electrode terminal 21P from the negative electrode terminal 21N. The external gasket 25 covers the surface of the disk portion 211 on the second direction Z2 side. The rivet portion 212 penetrates the external gasket 25 in the axial direction Z. The external gasket 25 covers the inner surface in the radial direction of the through-hole 21Nh of the negative electrode terminal 21N.

[0046] The internal gasket 26 covers the surface of the negative electrode terminal 21N on the second direction Z2 side. The internal gasket 26 is made of an insulating material. Therefore, the internal gasket 26 insulates the wound electrode body 10 from the negative electrode terminal 21N. The rivet portion 212 further penetrates the internal gasket 26 in the axial direction Z. Therefore, the rivet portion 212 is exposed to the inside of the case 20.

[0047] The annular gasket 27 has a circular outer shape. The annular gasket 27 covers the outer peripheral edge of the sealing plate 23. The annular gasket 27 is disposed between the outer peripheral edge of the sealing plate 23 and the crimped portion 22d of the cylindrical wall portion 22. The annular gasket 27 may be made of an insulating material or a conductive material. The case 20 does not necessarily have to include the annular gasket 27.

[0048] 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 the negative electrode terminal.

[0049] Furthermore, in this embodiment, the portion of the case 20 facing the first direction Z1 is composed of the positive electrode terminal 21P, the negative electrode terminal 21N, and the external gasket 25. However, the case 20 may further include a top plate portion as part of the above-described portion. The top plate portion may be located, for example, further inward from the negative electrode terminal 21N. The top plate portion may be arranged so as to be aligned with the positive electrode terminal 21P in the axial direction Z. The top plate portion may be insulated from the negative electrode terminal 21N. Furthermore, when the sealing plate 23 serves as the negative electrode terminal as described above, a top plate portion electrically insulated from the sealing plate 23 may be arranged in place of the negative electrode terminal 21N.

[0050] Next, the positive current collector plate 30P will be described. As shown in Figures 2, 3, and 5, the positive current collector plate 30P is disposed inside the case 20. The positive current collector plate 30P is disposed on the first direction Z1 side of the wound electrode body 10.

[0051] The positive electrode current collector 30P is provided to electrically connect the positive electrode 11P and the positive electrode terminal 21P. The positive electrode current collector 30P is joined by welding to the positive electrode uncoated portion 111PB of the positive electrode 11P. As a result, the positive electrode current collector 30P is positively charged. The positive electrode current collector 30P is joined by welding to the end of the rivet portion 212 of the positive electrode terminal 21P on the second direction Z2 side. As a result, the positive electrode terminal 21P is positively charged.

[0052] An internal gasket 26 is disposed 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. The internal gasket 26 also extends to the outer periphery of the positive current collector plate 30P. This also places the internal gasket 26 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.

[0053] The positive current collector plate 30P has a substantially circular disk-like shape and includes a central portion 31P, an outer peripheral edge portion 32P, a plurality of spokes 33P, and a plurality of pieces 35P.

[0054] The central portion 31P is positioned so as to overlap the rivet portion 212 of the positive electrode terminal 21P when viewed from the axial direction Z. The central portion 31P is connected to the case 20, thereby electrically connecting the positive electrode current collector plate 30P to the positive electrode terminal 21P. Specifically, the central portion 31P is joined to the rivet portion 212 of the positive electrode terminal 21P by welding.

[0055] The outer peripheral edge portion 32P is provided on the outer peripheral edge of the positive electrode current collector plate 30P. The outer peripheral edge portion 32P is located on the outer peripheral side of the central portion 31P. The outer peripheral edge portion 32P extends in an annular shape with the central portion 31P as the center. The outer peripheral edge portion 32P may contact the positive electrode uncoated portion 111PB of the positive electrode 11P. However, the outer peripheral edge portion 32P is not joined to the positive electrode uncoated portion 111PB.

[0056] The multiple spokes 33P are spaced apart from one another. The multiple 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 edge portion 32P. The spokes 33P have an outer shape such that the width dimension is approximately equal from the central portion 31P to the outer peripheral edge portion 32P.

[0057] The pieces 35P are spaced apart from one another and are arranged at equal intervals in the circumferential direction around the central portion 31P. The spokes 33P and the pieces 35P are arranged so that the spokes 33P and the pieces 35P alternate in the circumferential direction around the central portion 31P.

[0058] The piece portion 35P extends from the outer peripheral edge portion 32P toward the central portion 31P. The piece portion 35P is connected to the positive electrode 11P. Specifically, the piece portion 35P is joined to the positive electrode uncoated portion 111PB of the positive electrode 11P by welding. FIG. 5 schematically shows a path PP on the positive electrode current collector plate 30P from the joint between the piece portion 35P and the positive electrode uncoated portion 111PB to the joint between the central portion 31P and the rivet portion 212.

[0059] The piece 35P has a sectorial portion 351P and a neck portion 352P. The sectorial portion 351P is joined to the positive electrode uncoated portion 111PB of the positive electrode 11P by welding. The tip of the sectorial portion 351P faces the central portion 31P. The sectorial portion 351P extends toward the outer peripheral edge portion 32P so as to follow the two adjacent spokes 33P on both sides in the circumferential direction. This makes the surface area of ​​the sectorial portion 351P relatively large, facilitating welding to the positive electrode uncoated portion 111PB of the positive electrode 11P.

[0060] The neck portion 352P connects the outer peripheral edge portion 32P and the sectorial portion 351P. The neck portion 352P may contact the positive electrode uncoated portion 111PB of the positive electrode 11P. However, the neck portion 352P is not joined to 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 sectorial portion 351P. This makes it easier for the piece portion 35P to bend at the neck portion 352P.

[0061] Here, an example of a method for welding the central portion 31P and 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 piece portion 35P is welded to the positive electrode uncoated portion 111PB of the positive electrode 11P in advance. Next, a welding device is inserted from the second direction Z2 side of the wound electrode body 10 along the winding axis a of the wound electrode body 10. Then, while the welding device is pressed against the central portion 31P from the second direction Z2 side, the welding device welds the central portion 31P and the rivet portion 212 to each other. At this time, on the path PP, the connection portion between the spoke 33P and the central portion 31P and the connection portion between the spoke 33P and the outer peripheral edge portion 32P are significantly deflected. This allows the central portion 31P to be easily displaced in the axial direction Z relative to the piece portion 35P. Therefore, even if a welding device is pressed against the central portion 31P, the bond between the piece portion 35P and the positive electrode uncoated portion 111PB is prevented from being destroyed due to displacement of the central portion 31P, which in turn makes it easier to connect the positive electrode current collector plate 30P and the case 20.

[0062] Next, the negative electrode current collector 30N will be described. Fig. 7 is a plan view showing the negative electrode current collector in embodiment 1. As shown in Figs. 2, 3, 6, and 7, the negative electrode current collector 30N is disposed inside the case 20. The negative electrode current collector 30N is disposed on one side in the axial direction Z of the wound electrode body 10, i.e., on the second direction Z2 side.

[0063] 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 30N is joined to the negative electrode uncoated portion 111NB of the negative electrode 11N by welding. As a result, the negative electrode current collector 30N is negatively charged. The negative electrode current collector 30N is joined to the cylindrical wall portion 22 by being crimped together with the outer peripheral edge of the sealing plate 23 and the annular gasket 27 at the crimping portion 22d. As a result, the negative electrode terminal 21N connected to the cylindrical wall portion 22 is negatively charged.

[0064] The negative electrode current collector plate 30N has a substantially circular outer shape. The negative electrode current collector plate 30N includes a central portion 31N, an outer peripheral edge portion 32N, a plurality of spokes 33N, a plurality of first arm portions 34N, and a plurality of second arm portions 35N. In the first embodiment, the central portion (31), the outer peripheral edge portion (32), the spokes (33), the first arm portion (34), and the second arm portion (35) of the present disclosure each exemplify each of the above components included in the negative electrode current collector plate 30N.

[0065] The central portion 31N is disposed so as to overlap the center of the wound electrode body 10 when viewed from the axial direction Z. Specifically, the central portion 31N is positioned so as to overlap with the winding axis α when viewed from the axial direction Z. The central portion 31N may be in contact with the negative electrode uncoated portion 111NB of the negative electrode 11N. However, the central portion 31N is not joined to the negative electrode uncoated portion 111NB.

[0066] 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 makes it easy to inject the electrolyte through the through-hole 23h. Furthermore, when releasing the pressure inside the case 20, the negative electrode current collector plate 30N can be prevented from blocking 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.

[0067] 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 its center.

[0068] 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 case 20. In the present 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 crimped together with the outer peripheral edge of the sealing plate 23 and the annular gasket 27 at the crimping portion 22d. As a result, the outer peripheral edge portion 32N is electrically connected to the negative electrode terminal 21N connected to the cylindrical wall portion 22.

[0069] The outer peripheral edge portion 32N has an annular base portion 321 and a plurality of outermost peripheral portions 322. The annular base portion 321 extends annularly around the central portion 31N. The annular base portion 321 is not connected to the cylindrical wall portion 22. In other words, the annular base portion 321 is not crimped to the cylindrical wall portion 22 by the crimping portion 22d.

[0070] Each of the outermost peripheral portions 322 extends from the annular base portion 321 toward the outer periphery. The outermost peripheral portions 322 are spaced apart from one another. The outermost peripheral portions 322 are arranged at equal intervals in the circumferential direction around the central portion 31P. The outermost peripheral portions 322 are connected to the cylindrical wall portion 22. That is, the outermost peripheral portions 322 are crimped to the cylindrical wall portion 22 by crimping portions 22d. By connecting the outermost peripheral portions 322 that are spaced apart from one another to the cylindrical wall portion 22 by crimping, stress concentration on the outer peripheral edge portion 32N can be alleviated.

[0071] The spokes 33N are spaced apart from one another. The spokes 33N are arranged at equal intervals in the circumferential direction around the central portion 31N. The spokes 33N connect the central portion 31N and the outer peripheral edge portion 32N. The spokes 33N are spaced apart from one another from the central portion 31N to the outer peripheral edge portion 32N. The spokes 33N have outer diameters such that the width dimensions are approximately equal. The multiple spokes 33N are aligned radially with the multiple outermost portions 322. This makes it possible to suppress shear force from acting between the annular base portion 321 and the outermost portions 322 when the spokes 33N are bent in one direction in the axial direction Z.

[0072] The multiple first pieces 34N are spaced apart from one another and are arranged at equal intervals in the circumferential direction around the central portion 31N. Each of the multiple first pieces 34N is adjacent to two spokes 33N on each side in the circumferential direction.

[0073] The first arm portion 34N extends from the central portion 31N toward the outer peripheral edge portion 32N. The first arm portion 34N is connected to the negative electrode 11N. Specifically, the first arm portion 34N is joined to the negative electrode uncoated portion 111NB of the negative electrode 11N by welding. FIGS. 6 and 7 schematically show a first path PN1, which is a path on the negative electrode current collector plate 30N from the joint between the first arm portion 34N and the negative electrode uncoated portion 111NB to the joint between the outer peripheral edge portion 32N and the cylindrical wall portion 22. The first arm portion 34N extends along two adjacent spokes 33N. This increases the surface area of ​​the first arm portion 34N, facilitating welding to the negative electrode uncoated portion 111NB of the negative electrode 11N.

[0074] The second arm portions 35N are spaced apart from one another. The second arm portions 35N are arranged at equal intervals in the circumferential direction centered on the central portion 31N. Each of the second arm portions 35N is adjacent to two spokes 33N on each side in the circumferential direction. In other words, the first arm portion 34N and the second arm portion 35N are arranged in the circumferential direction centered on the central portion 31N, with the spokes 33N interposed between them.

[0075] The second arm 35N extends from the outer peripheral edge 32N toward the central portion 31N. The second arm 35N is connected to the negative electrode 11N. The second arm 35N is joined to the negative electrode uncoated portion 111NB of the negative electrode 11N by welding. FIGS. 6 and 7 schematically show a second path PN2, which is a path on the negative electrode current collector plate 30N from the joint between the second arm 35N and the negative electrode uncoated portion 111NB to the joint between the outer peripheral edge 32 and the cylindrical wall portion 22. The second arm 35N does not have to be joined to the negative electrode uncoated portion 111NB by welding.

[0076] The second arm 35N has a sectorial portion 351N and a neck portion 352N. The sectorial portion 351N is joined to the negative electrode uncoated portion 111NB of the negative electrode 11N by welding. The tip of the sectorial portion 351N faces the center portion 31N. The sectorial portion 351N extends along two adjacent spokes 33N on both sides in the circumferential direction. This makes the surface area of ​​the sectorial portion 351N relatively large, facilitating welding to the negative electrode uncoated portion 111NB of the negative electrode 11N.

[0077] The neck portion 352N connects the outer peripheral edge portion 32N and the sectorial portion 351N. The neck portion 352N may contact the negative electrode uncoated portion 111NB of the negative electrode 11N. However, the neck portion 352N is not joined to 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 sectorial portion 351N. This makes it easier for the second arm portion 35N to flex at the neck portion 352N.

[0078] Here, an example of a method of joining the outermost peripheral portion 322 of the outer peripheral edge portion 32N to the cylindrical wall portion 22 by crimping will be described. First, before joining the outermost peripheral portion 322 to the cylindrical wall portion 22 by crimping, the fan-shaped portions 351N of the first arm portion 34N and the second arm portion 35N are welded to the negative electrode uncoated portion 111NB of the negative electrode 11N in advance. Thereafter, the cylindrical wall portion 22 is crimped to form the crimped portion 22d. At this time, the connection portions between the spokes 33N and the central portion 31N and the connection portions between the spokes 33N and the outer peripheral edge portion 32N on the first path PN1 are significantly bent. As a result, the outermost peripheral portion 322 can be easily displaced in the axial direction Z relative to the first arm portion 34N. Therefore, when the outer peripheral edge portion 32N is connected to the cylindrical wall portion 22, even if the outer peripheral edge portion 32N is displaced in the axial direction Z, the bond between the first arm portion 34N and the negative electrode uncoated portion 111NB is prevented from being destroyed. Consequently, the negative electrode current collector plate 30N and the case 20 can be easily connected.

[0079] On the other hand, the second path PN2 is shorter than the first path PN1. Therefore, when current is applied to the negative electrode current collector plate 30N, the second path PN2 becomes the main conduction path. The relatively short second path PN2 can reduce heat generation during current application.

[0080] As described above, the energy storage cell 1 according to the first embodiment of the present disclosure includes a wound electrode assembly 10, a case 20, and a current collector 30. The wound electrode assembly 10 includes a first electrode 11A and a second electrode 11B. The case 20 houses the wound electrode assembly 10 and includes a first external terminal 21A. The current collector 30 is disposed within the case 20 on one side of the wound electrode assembly 10 in the axial direction Z. The current collector 30 is provided to electrically connect the first electrode 11A and the first external terminal 21A. The current collector 30 includes a central portion 31, an outer peripheral edge portion 32, spokes 33, a first arm portion 34, and a second arm portion 35. The central portion 31 is disposed so as to overlap the center of the wound electrode assembly 10 when viewed from the axial direction Z. The outer peripheral edge portion 32 is located on the outer peripheral side of the central portion 31. Either the outer peripheral edge portion 32 or the central portion 31 is connected to the case 20, thereby electrically connecting the current collecting plate 30 to the first external terminal 21A. The spokes 33 connect the central portion 31 to the outer peripheral edge portion 32. The first arm portion 34 extends from the central portion 31 toward the outer peripheral edge portion 32 and is connected to the first electrode 11A. The second arm portion 35 extends from the outer peripheral edge portion 32 toward the central portion 31 and is connected to the first electrode 11A.

[0081] According to the above configuration, the current collector plate 30 and the case 20 can be easily connected, and heat generation of the current collector plate 30 can be suppressed.

[0082] From another perspective, the above configuration allows the energy storage cell 1 to generate heat moderately when energized. As in the first embodiment of the present disclosure, when the outer peripheral edge portion 32 is connected to the case 20, for example, the path PN1 on the current collector plate 30, which is connected in this order from the first arm portion 34, the central portion 31, the spokes 33, and the outer peripheral edge portion 32, is relatively long. Therefore, 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, which is composed only of the second arm portion 35 and the outer peripheral edge portion 32, is relatively short. Therefore, the heat generated along this path PN2 when energized is relatively small. This makes it possible to provide an energy storage cell 1 that can generate heat moderately when energized.

[0083] Furthermore, in the first embodiment of the present disclosure, the first piece 34 and the second piece 35 are arranged side by side via the spokes 33 in the circumferential direction centered on the central portion 31 .

[0084] According to the above configuration, a long conductive path (first path PN1 in this embodiment) on the current collecting plate 30, which generates a relatively large amount of heat when current is applied, and a short path (second path PN2 in this embodiment) on the current collecting plate 30, which generates a relatively small amount of heat, are aligned in the circumferential direction. This makes it possible to reduce the uneven distribution of the amount of heat generated by the current collecting plate 30 when current is applied, in the circumferential direction.

[0085] Furthermore, in the first embodiment of the present disclosure, the first arm portion 34 and the second arm portion 35 are welded to the first electrode 11A.

[0086] According to the above configuration, the first arm 34 and the second arm 35 are reliably fixedly connected to the first electrode 11A. Consequently, a conductive path (first path PN1 in this embodiment) passing through the first arm 34 of the current collector plate 30 and a conductive path (second path PN2 in this embodiment) passing through the second arm 35 are more reliably formed.

[0087] Furthermore, in the first embodiment of the present disclosure, the case 20 includes a cylindrical wall portion 22 that covers the entire outer periphery of the wound electrode body 10. The outer periphery edge portion 32 is connected to the cylindrical wall portion 22, whereby the current collector plate 30 is electrically connected to the first external terminal 21A.

[0088] According to the above configuration, the conductive path from the current collector plate 30 to the first external terminal 21A includes the cylindrical wall portion 22 having a relatively large outer surface area. Therefore, heat generated when electricity is passed through the conductive path can be easily dissipated from the outer surface of the cylindrical wall portion 22.

[0089] (Embodiment 2) Next, a description will be given of a storage cell according to a second embodiment of the present disclosure. In the second embodiment of the present disclosure, the configurations of the first and second arms of the negative electrode current collector plate differ from those of the first embodiment of the present disclosure. Therefore, the description of the same configurations and effects as those of the first embodiment of the present disclosure will not be repeated.

[0090] Fig. 8 is a cross-sectional view showing a storage cell according to embodiment 2. Fig. 9 is a plan view showing a negative electrode current collector plate according to embodiment 2.

[0091] As shown in FIGS. 8 and 9, in the energy storage cell 1a according to the second embodiment of the present disclosure, the first arm 34a and the second arm 35a are aligned in the radial direction with the central portion 31 as the center.

[0092] According to the above configuration, the first pieces 34a and the second pieces 35a can be arranged compactly. As a result, for example, the number of first pieces 34a and the number of second pieces 35a are greater than in the first embodiment.

[0093] The multiple spokes 33 and the multiple first arm portions 34a are arranged so that the spokes 33 and the first arm portions 34a are alternately arranged in the circumferential direction centered on the central portion 31. The multiple spokes 33 and the multiple second arm portions 35a are arranged so that the spokes 33 and the second arm portions 35a are alternately arranged in the circumferential direction centered on the central portion 31.

[0094] (Embodiment 3) Next, a description will be given of an energy storage cell according to a third embodiment of the present disclosure. The third embodiment of the present disclosure differs from the first embodiment of the present disclosure mainly in that the current collector plate in the present disclosure is exemplified by a positive electrode current collector plate 30P. Therefore, the description of the same configuration and effects as those of the third embodiment of the present disclosure will not be repeated.

[0095] Fig. 10 is a cross-sectional view of the energy storage cell according to embodiment 3. Fig. 11 is another cross-sectional view of the energy storage cell according to embodiment 3. Fig. 12 is an exploded perspective view of the energy storage cell according to embodiment 3. Fig. 13 is another exploded perspective view of the energy storage cell according to embodiment 3.

[0096] 10 to 13, in the energy storage cell 1b according to the second embodiment of the present disclosure, the first electrode (11Ab) in the present disclosure is exemplified by a positive electrode 11Pb, and the second electrode (11Ab) in the present disclosure is exemplified by a negative electrode 11Nb. Furthermore, the first external terminal (21Ab) in the present disclosure is exemplified by a positive electrode terminal 21Pb, and the second external terminal (21Bb) in the present disclosure is exemplified by a negative electrode terminal 21Nb.

[0097] First, the positive current collector plate 30Pb in this embodiment will be described. FIG. 14 is a plan view showing a positive current collector plate in embodiment 3. As shown in FIGS. 10 to 12 and 14, the positive current collector plate 30Pb is exemplified as the current collector plate (30b) in the present disclosure. The central portion (31), outer peripheral edge portion (32), spokes (33), first piece portion (34b), and second piece portion (35b) in the present disclosure are (31P), outer peripheral edge portion (32P), spokes (33P), first piece portion (34Pb), and second piece portion (35Pb) included in the positive current collector plate 30P. Each is exemplified.

[0098] In the second embodiment, the positive electrode current collector plate 30P includes a plurality of first arm portions 34Pb and a plurality of second arm portions 35Pb.

[0099] The first arm portions 34Pb are spaced apart from one another and are arranged at equal intervals in the circumferential direction around the central portion 31P. Each of the first arm portions 34Pb is adjacent to two spokes 33P on each side in the circumferential direction.

[0100] The first arm portion 34Pb extends from the central portion 31P toward the outer peripheral edge portion 32P. The first arm portion 34Pb is connected to the positive electrode 11P. Specifically, the first arm portion 34Pb is joined to the positive electrode uncoated portion 111PB of the positive electrode 11P by welding. FIG. 14 schematically shows a first path PP1b, which is a path on the positive electrode current collector plate 30Pb from the joint between the first arm portion 34Pb and the positive electrode uncoated portion 111PB to the joint between the central portion 31P and the rivet portion 212. The first arm portion 34Pb extends along two adjacent spokes 33P. This relatively increases the surface area of ​​the first arm portion 34Pb, facilitating welding to the positive electrode uncoated portion 111PB of the positive electrode 11P. The first arm portion 34Pb does not have to be joined to the positive electrode uncoated portion 111PB by welding.

[0101] The second arm portions 35Pb are spaced apart from one another. The second arm portions 35Pb are arranged at equal intervals in the circumferential direction centered on the central portion 31P. Each of the second arm portions 35Pb is adjacent to two spokes 33P on each side in the circumferential direction. That is, the first arm portions 34Pb and the second arm portions 35Pb are arranged in the circumferential direction centered on the central portion 31P, with the spokes 33P interposed between them.

[0102] The second arm portion 35Pb extends from the outer peripheral edge portion 32P toward the central portion 31P. The second arm portion 35Pb is connected to the positive electrode 11P. The second arm portion 35Pb is joined to the positive electrode uncoated portion 111PB of the positive electrode 11P by welding. FIG. 14 schematically shows a second path PP2b, which is a path on the positive electrode current collector plate 30P from the joint between the second arm portion 35Pb and the positive electrode uncoated portion 111PB to the joint between the central portion 31P and the rivet portion 212.

[0103] The second arm 35Pb has a sectorial portion 351P and a neck portion 352P. The sectorial portion 351P is joined to the positive electrode uncoated portion 111PB of the positive electrode 11P by welding. The tip of the sectorial portion 351P faces the center portion 31P. The sectorial portion 351P extends along the two adjacent spokes 33P on both sides in the circumferential direction. This makes the surface area of ​​the sectorial portion 351P relatively large, facilitating welding to the positive electrode uncoated portion 111PB of the positive electrode 11P.

[0104] The neck portion 352P connects the outer peripheral edge portion 32P and the sectorial portion 351P. The neck portion 352P may contact the positive electrode uncoated portion 111PB of the positive electrode 11P. However, the neck portion 352P is not joined to 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 sectorial portion 351P. This makes it easier for the second arm portion 35Pb to bend at the neck portion 352P.

[0105] Here, an example of a method for welding the central portion 31P and the rivet portion 212 in this embodiment will be described. First, before the central portion 31P is welded to the rivet portion 212, the fan-shaped portions 351P of the first arm portion 34Pb and the second arm portion 35Pb are welded in advance 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 a of the wound electrode body 10. Then, while the welding device is pressed against the central portion 31P from the second direction Z2 side, the welding device welds the central portion 31P and the rivet portion 212 to each other. At this time, on the second path PP2b, the spoke 33P and the central portion 31P are welded to each other. The connection portion between the spoke 33P and the outer peripheral edge portion 32P and the second arm portion 35Pb is significantly bent. This allows the central portion 31P to be easily displaced in the axial direction Z relative to the second arm portion 35Pb. Therefore, even if a welding device is pressed against the central portion 31P, the displacement of the central portion 31P prevents the bond between the second arm portion 35Pb and the positive electrode uncoated portion 111PB from being destroyed. This in turn makes it easier to connect the positive electrode current collector plate 30Pb to the case 20.

[0106] On the other hand, the first path PP1b is shorter than the second path PP2b. Therefore, when current is applied to the positive current collector plate 30Pb, the first path PP1b serves as the main conductive path. The relatively short first path PP1b can reduce heat generation during current application.

[0107] Next, a description will be given of the negative electrode current collector plate 30Nb in embodiment 3. As shown in Fig. 10, Fig. 11 and Fig. 13, in embodiment 3, the negative electrode current collector plate 30Nb includes a plurality of pieces 34Nb.

[0108] The pieces 34Nb are spaced apart from one another and are arranged at equal intervals in the circumferential direction around the central portion 31N. The spokes 33N and the pieces 34Nb are arranged so that the spokes 33N and the pieces 34Nb alternate in the circumferential direction around the central portion 31N.

[0109] The piece portion 34Nb extends from the central portion 31N toward the outer peripheral edge portion 32N. The piece portion 34Nb is connected to the negative electrode 11N. Specifically, the piece portion 34Nb is joined to the negative electrode uncoated portion 111NB of the negative electrode 11N by welding. FIG. 13 schematically shows a path PNb, which is a path on the negative electrode current collector plate 30N from the joint between the piece portion 34Nb and the negative electrode uncoated portion 111NB to the joint between the outer peripheral edge portion 32N and the cylindrical wall portion 22. The piece portion 34Nb extends along two adjacent spokes 33N. This makes the surface area of ​​the piece portion 34Nb relatively large, facilitating welding to the negative electrode uncoated portion 111NB of the negative electrode 11N.

[0110] 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 crimping will be described. First, before joining the outermost peripheral portion 322 to the cylindrical wall portion 22 by crimping, the piece portion 34Nb is welded to the negative-electrode uncoated portion 111NB of the negative electrode 11N in advance. Then, the cylindrical wall portion 22 is crimped to form the crimped portion 22d. At this time, the connection portion between the spoke 33N and the central portion 31N and the connection portion between the spoke 33N and the outer peripheral edge portion 32N on the path PNb are significantly deflected. This allows the outermost peripheral portion 322 to be easily displaced in the axial direction Z relative to the piece portion 34Nb. Therefore, 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, destruction of the bond between the piece portion 34Nb and the negative-electrode uncoated portion 111NB is suppressed. This in turn makes it easier to connect the negative electrode current collector plate 30Nb and the case 20.

[0111] As described above, the energy storage cell 1b according to the third embodiment of the present disclosure includes a wound electrode assembly 10, a case 20, and a current collector 30b. The wound electrode assembly 10 includes a first electrode 11Ab and a second electrode 11B. The case 20 houses the wound electrode assembly 10 and includes a first external terminal 21Ab. The current collector 30b is disposed on one side of the wound electrode assembly 10 in the axial direction Z within the case 20. The current collector 30b is provided to electrically connect the first electrode 11Ab and the first external terminal 21Ab. The current collector 30b includes a central portion 31, an outer peripheral edge portion 32, spokes 33, a first arm 34b, and a second arm 35b. The central portion 31 is disposed so as to overlap with the center of the wound electrode assembly 10 when viewed from the axial direction Z. The outer peripheral edge portion 32 is located on the outer peripheral side of the central portion 31. When either the outer peripheral edge portion 32 or the central portion 31 is connected to the case 20, the current collector plate 30b is electrically connected to the first external terminal 21Ab. The spokes 33 connect the central portion 31 and the outer peripheral edge portion 32. The first piece 34b extends from the central portion 31 toward the outer peripheral edge 32 and is connected to the first electrode 11Ab. The second piece 35b extends from the outer peripheral edge 32 toward the central portion 31 and is connected to the first electrode 11Ab.

[0112] According to the above configuration, the current collector plate 30b can be easily connected to the case 20, and heat generation from the current collector plate 30b can be suppressed.

[0113] From another perspective, the above configuration allows the energy storage cell 1b to generate heat moderately when energized. For example, when the central portion 31 is connected to the case 20 as in the third embodiment of the present disclosure, the path PP2b on the current collector 30b, which is connected in this order from the second arm 35b, the outer peripheral edge 32, the spokes 33, and the central portion 31, is relatively long. Therefore, when energized, the current collector 30b generates relatively large amounts of heat along the path PP2b. Meanwhile, the path PP1b on the current collector 30b, which is formed only from the first arm 34b and the central portion 31, is relatively short. Therefore, the heat generated along the path PP1b when energized is relatively small. This makes it possible to provide an energy storage cell 1b that can generate heat moderately when energized.

[0114] Furthermore, in the third embodiment of the present disclosure, the first piece 34b and the second piece 35b are arranged side by side via the spokes 33 in the circumferential direction around the central portion 31.

[0115] According to the above configuration, a long conductive path (second path PP2b in this embodiment) on the current collector 30b, which generates a relatively large amount of heat when current is applied, and a short path (first path PP1b in this embodiment) on the current collector 30b, which generates a relatively short amount of heat, are aligned in the circumferential direction, thereby reducing the uneven distribution of the amount of heat generated by the current collector 30b when current is applied.

[0116] Furthermore, in the third embodiment of the present disclosure, the first piece 34b and the second piece 35b are welded to the first electrode 11Ab.

[0117] With the above configuration, the first arm 34b and the second arm 35b are securely connected to the first electrode 11Ab, which in turn more reliably forms a conductive path (first path PP1b in this embodiment) that passes through the first arm 34b of the current collector plate 30b, and a conductive path (second path PP2b in this embodiment) that passes through the second arm 35b.

[0118] Furthermore, in the third embodiment of the present disclosure, the first external terminal 21Ab is positioned so as to overlap the central portion 31b when viewed from the axial direction Z. Furthermore, the central portion 31b is connected to the case 20, whereby the current collecting plate 30b is electrically connected to the first external terminal 21Ab.

[0119] According to the above configuration, the conductive path from the current collector plate 30b to the first external terminal 21Ab can be shortened, and heat generation in the conductive path can be suppressed.

[0120] (Embodiment 4) Next, a description will be given of a storage cell according to a fourth embodiment of the present disclosure. In the fourth embodiment of the present disclosure, the first and second arm portions of the positive electrode current collector plate differ from those of the third embodiment of the present disclosure. Therefore, the description of the same configuration and effects as those of the third embodiment of the present disclosure will not be repeated.

[0121] Fig. 15 is a plan view showing a storage cell according to embodiment 4. Fig. 16 is a plan view showing a positive electrode current collector plate according to embodiment 4.

[0122] As shown in FIGS. 15 and 16, in the energy storage cell 1c according to the fourth embodiment of the present disclosure, the first arm 34c and the second arm 35c are aligned in the radial direction with the central portion 31 as the center.

[0123] According to the above configuration, the first pieces 34c and the second pieces 35c can be arranged compactly. As a result, the number of first pieces 34c and the number of second pieces 35c are greater than in the third embodiment, for example.

[0124] The multiple spokes 33 and the multiple first arm portions 34c are arranged so that the spokes 33 and the first arm portions 34c are alternately arranged in the circumferential direction centered on the central portion 31. The multiple spokes 33 and the multiple second arm portions 35c are arranged so that the spokes 33 and the second arm portions 35c are alternately arranged in the circumferential direction centered on the central portion 31.

[0125] (Embodiment 5) Next, a description will be given of a storage cell according to a fifth embodiment of the present disclosure. The fifth embodiment of the present disclosure differs from the storage cell 1b according to the third embodiment of the present disclosure in that a negative electrode current collector plate is not provided. Therefore, the configuration and effects of the fifth embodiment of the present disclosure will not be described repeatedly.

[0126] Fig. 17 is a cross-sectional view of the energy storage cell according to embodiment 5. Fig. 18 is an exploded perspective view showing the energy storage cell according to embodiment 5.

[0127] As shown in FIGS. 17 and 18, in an energy storage cell 1d according to the fifth embodiment, the case 20 does not include an annular gasket.

[0128] In this embodiment, the outer peripheral edge of the sealing plate 23d 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 crimped portion.

[0129] 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 joined to the negative electrode uncoated portion 111NB of the negative electrode 11N by welding. 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. Note that the sealing plate 23d may also be the negative electrode terminal.

[0130] The sealing plate 23d has an annular ridge portion 231, multiple radial ridge portions 232, and multiple welds 233. When viewed from the axial direction Z, the annular ridge portion 231 extends in an annular shape centered on the winding axis α of the wound electrode body 10. The annular ridge portion 231 protrudes toward the first direction Z1. In other words, 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.

[0131] The multiple radial ridge portions 232 are arranged so as to be spaced apart from each other in the circumferential direction centered on the winding axis α of the wound electrode body 10 when viewed from the axial direction Z. The multiple radial ridge portions 232 are arranged at equal intervals in the circumferential direction.

[0132] Each of the plurality of radial ridges 232 extends in a radial direction centered on the winding axis α of the wound electrode body 10. The radial ridges 232 are continuous with the annular ridges 231.

[0133] The radial ridge portion 232 protrudes in the first direction Z1. That is, the radial ridge portion 232 protrudes toward the wound electrode body 10. The radial ridge portion 232 contacts the negative electrode uncoated portion 111NB of the negative electrode 11N.

[0134] The plurality of welded portions 233 are portions of the sealing plate 23d that are joined to the negative electrode uncoated portion 111NB by welding. The plurality of welded portions 233 are formed on the annular ridge portion 231. In the annular ridge portion 231, the multiple welds 233 are formed to extend along the circumferential direction. The multiple welds 233 are formed on each of the multiple radial ridge portions 232. In the radial ridge portion 232, the welds 233 are formed to extend along the radial direction. The annular ridge portion 231 and the multiple radial ridge portions 232 may be thinner than other portions of the sealing plate 23d. This makes it easier to form the welds 233.

[0135] In the above-described embodiments, configurations that can be combined may be combined with each other. For example, a positive electrode current collector plate in one embodiment may be combined with a negative electrode current collector plate in another embodiment.

[0136] The embodiments disclosed herein should be considered to be illustrative in all respects and not restrictive. The scope of the present disclosure is defined by the claims, not by the description of the above embodiments, and is intended to include all modifications within the meaning and scope of the claims. [Explanation of symbols]

[0137] 1, 1a, 1b, 1c, 1d storage cell, 10 wound electrode body, 11A, 11Ab first electrode, 11B, 11Bb second electrode, 11P, 11Pb positive electrode, 111PA positive electrode coated portion, 111PB positive electrode uncoated portion, 111PC extension portion, 112P positive electrode composite layer, 11N, 11Nb negative electrode, 111N negative electrode current collector, 111NA negative electrode coated portion, 111NB negative electrode uncoated portion, 111NC111P positive electrode current collector, 112N negative electrode composite layer, 12 separator, 20 case, 21A, 21Ab first external terminal, 21B, 21Bb second external terminal, 21P, 21Pb positive electrode terminal, 211 disk portion, 212 Rivet part: 21N, 21Nb Negative electrode terminal, 22 cylindrical wall portion, 22d crimping portion, 23, 23d sealing plate, 231 annular ridge portion, 232 radial ridge portion, 233 welded portion, 24 sealing plug, 25 outer gasket, 26 inner gasket, 27 annular gasket, 30, 30b current collector plate, 30N, 30Nb negative electrode current collector plate, 30P, 30Pb positive electrode current collector plate, 31, 31N, 31P, 31b center portion, 32, 32N, 32P outer peripheral edge portion, 321 annular base portion, 322 outermost peripheral portion, 33, 33N, 33P spokes, 34Nb, 35P piece portion, 34, 34N, 34Pb, 34a, 34b, 34c 1st piece, 35,35N,35Pb,35a,35b,35c 2nd piece, 351N,351P fan-shaped part, 352N,352P neck.

Claims

1. a wound electrode body including a first electrode and a second electrode; a case that houses the wound electrode body and includes a first external terminal; a current collector plate disposed on one side of the wound electrode body in the axial direction within the case, and provided to electrically connect the first electrode and the first external terminal, The current collecting plate is The center and A peripheral edge portion; Spokes and A first piece; a second piece; the central portion is disposed so as to overlap the center of the wound electrode body when viewed in the axial direction, the outer peripheral edge portion is located on the outer peripheral side of the central portion, the current collecting plate is electrically connected to the first external terminal by connecting either the outer peripheral edge portion or the central portion to the case; the spokes connect the central portion and the outer circumferential edge portion; the first piece extends from the central portion toward the outer peripheral edge portion and is connected to the first electrode; The second arm extends from the outer peripheral edge toward the central portion and is connected to the first electrode.

2. The energy storage cell according to claim 1 , wherein the first arm and the second arm are arranged side by side via the spoke in a circumferential direction centered on the central portion.

3. The energy storage cell according to claim 1 , wherein the first arm and the second arm are aligned in a radial direction with the central portion as a center.

4. The energy storage cell according to claim 1 , wherein the first piece and the second piece are welded to the first electrode.

5. the case includes a cylindrical wall portion that covers the entire outer circumferential side of the wound electrode body, The energy storage cell according to claim 1 , wherein the outer peripheral edge portion is connected to the cylindrical wall portion, thereby electrically connecting the current collector plate to the first external terminal.

6. the first external terminal is positioned so as to overlap the central portion when viewed from the axial direction, The energy storage cell according to claim 1 , wherein the central portion is connected to the case, thereby electrically connecting the current collector plate to the first external terminal.

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