Energy storage cell

Abstract

To provide an energy storage cell that generates a moderate amount of heat when powered on. [Solution] In the energy storage cell 1 according to this disclosure, the current collector plate 30 includes a central portion 31, an outer peripheral edge portion 32, spokes 33, a first piece portion 34, and a second piece portion 35. The central portion 31 is positioned so as to coincide with 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. The current collector plate 30 is electrically connected to the first external terminal 21A by connecting either the outer peripheral edge portion 32 or the central portion 31 to the case 20. The spokes 33 connect the central portion 31 and the outer peripheral edge portion 32. The first piece 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 piece 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 a storage battery cell. 【Background Art】 【0002】 Patent Document 1 discloses a cylindrical battery in which an electrode group composed of a positive electrode, a negative electrode, and a separator is wound in a spiral shape and housed in a battery case. As a connection method for the lead portion of the positive electrode, a tabless method is shown. The lead portion provided on the current collector plate of the positive electrode is welded to the back surface of the lid. The overlapping lead portions of the negative electrode and the inner bottom of the case are spot welded. 【Prior Art Documents】 【Patent Documents】 【0003】 【Patent Document 1】 Japanese Patent No. 3324372 【Summary of the Invention】 【Problems to be Solved by the Invention】 【0004】 Storage battery cells such as the cylindrical battery disclosed in Patent Document 1 may be charged by rapid charging. When the storage battery cell is rapidly charged, it is preferable that the temperature of the storage battery cell rises to a certain extent. However, in order to maintain the function of the storage battery cell, it is necessary to suppress excessive heat generation in the storage battery cell. 【0005】 The present disclosure has been made in view of the above problems, and an object thereof is to provide a storage battery cell that can generate heat moderately during energization. 【Means for Solving the Problems】 【0006】 A storage cell according to this disclosure comprises a wound electrode body, a case, and a current collector plate. The wound electrode body includes a first electrode and a second electrode. The case houses the wound electrode body and includes a first external terminal. The current collector plate is located within the case on one side of the wound electrode body in the axial direction. 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 edge portion, spokes, a first piece portion, and a second piece portion. The central portion is positioned to coincide with the center of the wound electrode body when viewed from the axial direction. The outer edge portion is located on the outer periphery of the central portion. The current collector plate is electrically connected to the first external terminal by either the outer edge portion or the central portion being connected to the case. The spokes connect the central portion and the outer edge portion. The first piece portion extends from the central portion toward the outer edge portion and is connected to the first electrode. The second piece extends from the outer edge toward the center and is connected to the first electrode. 【0007】 In the above configuration, firstly, when the outer edge is connected to the case, the path on the current collector plate, consisting of the first piece, central part, spokes, and outer edge in that order, becomes 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 consisting only of the second piece and outer edge becomes relatively short. Therefore, the amount of heat generated in this path when energized is relatively small. This makes it possible to provide an energy storage cell that generates a moderate amount of heat when energized. Secondly, when the central part is connected to the case, the path on the current collector plate, consisting of the second piece, outer edge, spokes, and central part in that order, becomes 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 consisting only of the first piece and central part becomes relatively short. Therefore, the amount of heat generated in this path when energized is relatively small. This makes it possible to provide an energy storage cell that generates a moderate amount of heat when energized. 【0008】 In the energy storage cell according to this disclosure, preferably, the first piece and the second piece are arranged via spokes in the circumferential direction centered on the central portion. 【0009】 According to the above configuration, long paths on the current collector plate that generate relatively large amounts of heat when energized and short paths on the current collector plate that generate relatively small amounts of heat are arranged relative to each other in the circumferential direction. This makes it possible to reduce the uneven distribution of heat generated by the current collector plate in the circumferential direction when energized. 【0010】 In the energy storage cell according to this disclosure, preferably, the first piece and the second piece are arranged radially with respect to the central part. With this configuration, the first piece and the second piece can be arranged compactly. 【0011】 In the energy storage cell according to this disclosure, preferably, the first piece and the second piece are welded to the first electrode 11A. 【0012】 With the above configuration, the first and second pieces are securely fixed and connected by the first electrode. Consequently, the conductive paths through the first piece and the conductive paths through the second piece in the current collector plate are more reliably formed. 【0013】 In the energy storage cell according to this disclosure, preferably, the case includes a cylindrical wall portion that covers the entire outer circumference of the wound electrode body. The outer peripheral edge 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 collector plate to the first external terminal includes a cylindrical wall portion with a relatively large outer surface area. Therefore, the heat generated when current 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 this disclosure, preferably, the first external terminal is positioned so as to overlap with the central portion when viewed from the axial direction. The central portion is connected to the case, thereby electrically connecting the current collector plate to the first external terminal. 【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, a power storage cell that can moderately generate heat when energized can be provided. 【Brief Description of the Drawings】 【0018】 [Figure 1] It is a perspective view showing a power storage cell according to Embodiment 1. [Figure 2] It is a cross-sectional view of the power storage cell of FIG. 1 seen in the direction of the arrow along line II-II. [Figure 3] It is a cross-sectional view of the power storage cell of FIG. 1 seen in the direction of the arrow along line III-III. [Figure 4] It is a perspective view showing a wound electrode body partially disassembled. [Figure 5] It is an exploded perspective view showing a power storage cell according to Embodiment 1. [Figure 6] It is another exploded perspective view showing a power storage cell according to Embodiment 1. [Figure 7] It is a plan view showing a negative electrode current collector plate in Embodiment 1. [Figure 8] It is a cross-sectional view showing a power storage cell according to Embodiment 2. [Figure 9] It is a plan view showing a negative electrode current collector plate in Embodiment 2. [Figure 10] It is a cross-sectional view of a power storage cell according to Embodiment 3. [Figure 11] It is another cross-sectional view of a power storage cell according to Embodiment 3. [Figure 12] It is an exploded perspective view showing a power storage cell according to Embodiment 3. [Figure 13] It is another exploded perspective view showing a power storage cell according to Embodiment 3. [Figure 14] It is a plan view showing a positive electrode current collector plate in Embodiment 3. [Figure 15] It is a plan view showing a power storage cell according to Embodiment 4. [Figure 16] It is a plan view showing a positive electrode current collector plate in Embodiment 4. [Figure 17] It is a cross-sectional view of a power storage cell according to Embodiment 5. [Figure 18] This is an exploded perspective view showing a disassembled energy storage cell according to Embodiment 5. [Modes for carrying out the invention] 【0019】 Hereinafter, energy storage cells according to each embodiment of this disclosure will be described with reference to the drawings. The same or corresponding parts in the drawings are denoted by the same reference numerals, and their descriptions will not be repeated. 【0020】 (Embodiment 1) Figure 1 is a perspective view showing a storage cell according to Embodiment 1. Figure 2 is a cross-sectional view of the storage cell of Figure 1 taken in the direction of the arrow II-II. Figure 3 is a cross-sectional view of the storage cell of Figure 1 taken in the direction of the arrow III-III. 【0021】 As shown in Figures 1 to 3, the energy storage cell 1 is a cylindrical battery. The energy storage cell 1 comprises a wound electrode body 10, a case 20, a positive electrode current collector plate 30P, and a negative electrode current collector plate 30N. In Embodiment 1, the negative electrode current collector plate 30N is exemplified as the current collector plate (30) in this disclosure. 【0022】 First, let's describe the wound electrode body 10. Figure 4 is a perspective view showing the wound electrode body in a partially disassembled state. As shown in Figures 2 to 4, the wound electrode body 10 is wound into a cylindrical shape. In Figure 4, the state in which the winding of the wound electrode body 10 has slightly unraveled is illustrated. 【0023】 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 such that the positive electrode 11P, the negative electrode 11N, and the separator 12 surround the winding axis α. In Embodiment 1, the negative electrode 11N is exemplified as the first electrode (11A) in this disclosure, and the positive electrode 11P is exemplified as the second electrode (11B). 【0024】 The positive electrode 11P and the negative electrode 11N have a sheet-like outer shape. The wound electrode body 10 is composed of a group of electrode plates in which the positive electrode 11P and the negative electrode 11N are wound around a separator 12. 【0025】 The separator 12 is placed between the positive electrode 11P and the negative electrode 11N. The separator 12 separates the positive electrode 11P (positive electrode active material) and the negative electrode 11N (negative electrode active material) while allowing ions (for example, lithium ions) to move between them. 【0026】 The positive electrode 11P includes a positive electrode current collector 111P and a positive electrode composite layer 112P. The positive electrode current collector 111P is made of, for example, aluminum. 【0027】 The positive electrode composite layer 112P is coated on both radial surfaces of the positive electrode current collector 111P (positive electrode coated portion 111PA, described later). The positive electrode composite layer 112P is in close contact with the separator 12. The positive electrode composite layer 112P is formed by coating the surface of the positive electrode current collector 111P with a positive electrode slurry and drying it. The positive electrode slurry is a slurry prepared by kneading the materials of the positive electrode composite layer 112P (positive electrode active material, binder, etc.) with a solvent. The thickness of the positive electrode composite layer 112P is, for example, 0.1 μm or more and 1000 μm or less. 【0028】 The positive electrode current collector 111P includes a positive electrode coated portion 111PA and a positive electrode uncoated portion 111PB. The positive electrode coated portion 111PA is the part of the positive electrode current collector 111P to which the positive electrode composite material layer 112P is coated. In other words, the positive electrode coated portion 111PA is the part that is not exposed because it is covered by the positive electrode composite material layer 112P. 【0029】 The uncoated positive electrode portion 111PB is the portion of the positive electrode current collector 111P that is not covered by the positive electrode composite layer 112P and is exposed. The uncoated positive electrode portion 111PB is located on the first direction Z1 side along the axial direction Z, compared to the coated positive electrode portion 111PA. Specifically, the uncoated positive electrode portion 111PB protrudes from the coated positive electrode portion 111PA on the first direction Z1 side. The uncoated positive electrode portion 111PB is bent radially inward. 【0030】 The uncoated positive electrode portion 111PB includes a plurality of extensions 111PC. The plurality of extensions 111PC are aligned along the winding direction of the wound electrode body 10. 【0031】 The negative electrode 11N includes a negative electrode current collector 111N and a negative electrode composite layer 112N. The negative electrode current collector 111N is made of, for example, copper. 【0032】 The negative electrode composite layer 112N is coated on both radial surfaces of the negative electrode current collector 111N (the negative electrode coated portion 111NA described later). The negative electrode composite layer 112N is in close contact with the separator 12. The negative electrode composite layer 112N is formed by coating the surface of the negative electrode current collector 111N with a negative electrode slurry and drying it. The negative electrode slurry is a slurry prepared by kneading the materials of the negative electrode composite layer 112N (such as negative electrode active material and binder) with a solvent. The thickness of the negative electrode composite layer 112N is, for example, 0.1 μm or more and 1000 μm or less. 【0033】 The negative electrode current collector 111N includes a negative electrode coated portion 111NA and a negative electrode uncoated portion 111NB. The negative electrode coated portion 111NA is the part of the negative electrode current collector 111N to which the negative electrode composite material layer 112N is coated. In other words, the negative electrode coated portion 111NA is the part that is not exposed because it is covered by the negative electrode composite material layer 112N. 【0034】 The uncoated negative electrode portion 111NB is the portion of the negative electrode current collector 111N that is not covered by the negative electrode composite layer 112N and is exposed. The uncoated negative electrode portion 111NB is located in a second direction Z2 along the axial direction, compared to the coated negative electrode portion 111NA. The second direction Z2 is the opposite direction to the first direction Z1. The uncoated negative electrode portion 111NB protrudes from the coated negative electrode portion 111NA in the second direction Z2 along the axial direction Z. The uncoated negative electrode portion 111NB is bent radially inward. 【0035】 The uncoated negative electrode portion 111NB includes a plurality of extensions 111NC. The plurality of extensions 111NC are aligned along the winding direction of the wound electrode body 10. 【0036】 Next, we will describe Case 20. Figure 5 is an exploded perspective view showing a storage cell according to Embodiment 1. Figure 6 is another exploded perspective view showing a storage cell according to Embodiment 1. 【0037】 As shown in Figures 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 Embodiment 1, the negative electrode terminal 21N is exemplified as the first external terminal (21A) in this disclosure, and the positive electrode terminal 21P is exemplified as the second external terminal (21B) in this disclosure. 【0038】 The positive electrode terminal 21P is located 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 positioned perpendicular to the axial direction Z. The negative electrode terminal 21N is provided with a through hole 21Nh. Therefore, the negative electrode terminal 21N has an annular outer shape when viewed from the axial direction Z. The negative electrode terminal 21N is located between the disk portion 211 and the wound electrode body 10 in the axial direction Z. The rivet portion 212 is inserted through the through hole 21Nh. The rivet portion 212 extends into the interior of the case 20. The material constituting the negative electrode terminal 21N is not particularly limited, but it is formed from aluminum, copper, or stainless steel, etc. 【0040】 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 it is formed from aluminum, copper, or stainless steel, etc. 【0041】 A crimped portion 22d is formed at the end of the cylindrical wall portion 22 on the second direction Z2 side. The crimped portion 22d is formed in an annular shape along the circumferential direction of the wound electrode body 10. Figures 5 and 6 show the cylindrical wall portion 22 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 edge of the sealing plate 23. The sealing plate 23 may also 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 from aluminum, copper, or stainless steel, etc. 【0043】 The sealing plate 23 has a through hole 23h formed therein. The through hole 23h may 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 from the axial direction Z. 【0044】 The sealing plug 24 is inserted through a through hole 23h in 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 to release pressure inside the case 20 when the pressure inside the case 20 becomes excessively high. 【0045】 The external gasket 25 is positioned between the positive terminal 21P and the negative terminal 21N. The external gasket 25 is made of an insulating material. Therefore, the external gasket 25 insulates the positive terminal 21P and the negative terminal 21N. The external gasket 25 covers the second direction Z2 side surface of the disk portion 211. The rivet portion 212 penetrates the external gasket 25 in the axial direction Z. The external gasket 25 covers the radial inner surface of the through hole 21Nh of the negative terminal 21N. 【0046】 The internal gasket 26 covers the second direction Z2 side surface of the negative electrode terminal 21N. 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 inside the case 20. 【0047】 The annular gasket 27 has an annular outer shape. The annular gasket 27 covers the outer edge of the sealing plate 23. The annular gasket 27 is positioned between the outer 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. Note that 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 an 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 terminal. 【0049】 Furthermore, in this embodiment, the portion of the case 20 facing the first direction Z1 is composed of a positive terminal 21P, a negative terminal 21N, and an external gasket 25. However, as part of the above portion, the case 20 may further have a top plate portion. The top plate portion may be located, for example, further inward from the negative terminal 21N. The top plate portion may be arranged in line with the positive terminal 21P in the axial direction Z. The top plate portion may be insulated from the negative terminal 21N. Also, if the sealing plate 23 becomes the negative terminal as described above, a top plate portion electrically insulated from the sealing plate 23 may be provided instead of the negative terminal 21N. 【0050】 Next, the positive electrode current collector plate 30P will be described. As shown in Figures 2, 3, and 5, the positive electrode current collector plate 30P is located inside the case 20. The positive electrode current collector plate 30P is located on the first direction Z1 side of the wound electrode body 10. 【0051】 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 joined to the unpainted positive electrode portion 111PB of the positive electrode 11P by welding. As a result, the positive electrode current collector plate 30P is positively charged. The positive electrode current collector plate 30P is also joined to the end of the rivet portion 212 of the positive electrode terminal 21P on the second direction Z2 side by welding. As a result, the positive electrode terminal 21P is positively charged. 【0052】 An internal gasket 26 is placed between the positive electrode current collector plate 30P and the negative electrode terminal 21N. This electrically insulates the positive electrode current collector plate 30P and the negative electrode terminal 21N from each other. Furthermore, the internal gasket 26 extends to the outer circumference of the positive electrode current collector plate 30P. As a result, the internal gasket 26 is also placed between the positive electrode current collector plate 30P and the cylindrical wall portion 22. Therefore, the positive electrode current collector plate 30P and the cylindrical wall portion 22 are electrically insulated from each other. 【0053】 The positive electrode current collector plate 30P has a roughly disc-shaped outer form. The positive electrode current collector plate 30P includes a central portion 31P, an outer peripheral edge portion 32P, a plurality of spokes 33P, and a plurality of side portions 35P. 【0054】 The central portion 31P is positioned so as to overlap with the rivet portion 212 of the positive terminal 21P when viewed from the axial direction Z. The central portion 31P is connected to the case 20, thereby electrically connecting the positive current collector plate 30P to the positive terminal 21P. Specifically, the central portion 31P is joined to the rivet portion 212 of the positive 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 be in contact with the unpainted positive electrode portion 111PB of the positive electrode 11P. However, the outer peripheral edge portion 32P is not joined to the unpainted positive electrode portion 111PB. 【0056】 Multiple spokes 33P are spaced apart from each other. Multiple spokes 33P are arranged at equal intervals in the circumferential direction with respect to the central portion 31P. Spokes 33P connect the central portion 31P and the outer edge portion 32P. Spokes 33P have an outer shape such that their width is approximately equal from the central portion 31P to the outer edge portion 32P. 【0057】 Multiple side sections 35P are spaced apart from each other. Multiple side sections 35P are arranged at equal intervals in the circumferential direction with respect to the central section 31P. Multiple spokes 33P and multiple side sections 35P are arranged such that the spokes 33P and side sections 35P alternate in the circumferential direction with respect to the central section 31P. 【0058】 The outer edge portion 32P extends from the outer edge portion 32P toward the central portion 31P. The outer edge portion 35P is connected to the positive electrode 11P. Specifically, the outer edge portion 35P is joined to the unpainted positive electrode portion 111PB of the positive electrode 11P by welding. Figure 5 schematically shows the path PP on the positive electrode current collector plate 30P from the joint between the outer edge portion 35P and the unpainted positive electrode portion 111PB to the joint between the central portion 31P and the rivet portion 212. 【0059】 The single piece 35P has a fan-shaped portion 351P and a neck portion 352P. The fan-shaped portion 351P is joined to the unpainted positive electrode 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 both sides in the circumferential direction. This makes the surface area of ​​the fan-shaped portion 351P relatively large, facilitating welding to the unpainted positive electrode portion 111PB of the positive electrode 11P. 【0060】 The neck portion 352P connects the outer peripheral edge portion 32P and the fan-shaped portion 351P. The neck portion 352P may be in contact with the uncoated positive electrode portion 111PB of the positive electrode 11P. However, the neck portion 352P is not joined to the uncoated positive electrode 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. This makes it easier for one side portion 35P to bend at the neck portion 352P. 【0061】 Here, an example of a welding method between 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 portion 351P of the side portion 35P is welded in advance to the uncoated positive electrode portion 111PB of the positive electrode 11P. Next, a welding device is inserted from the second direction Z2 side of the wound electrode body 10 along the winding axis α of the wound electrode body 10. Then, while the welding device is pressed against the central portion 31P from the second direction Z2 side, the central portion 31P and the rivet portion 212 are welded to each other by the welding device. At this time, along 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, bend significantly. As a result, the central portion 31P can be easily displaced in the axial direction Z relative to the side portion 35P. Therefore, even if a welding device is pressed against the central part 31P, the displacement of the central part 31P prevents the joint between the single part 35P and the unpainted positive electrode part 111PB from being destroyed. Consequently, the connection between the positive electrode current collector plate 30P and the case 20 becomes easier. 【0062】 Next, the negative electrode current collector plate 30N will be described. Figure 7 is a plan view showing the negative electrode current collector plate in Embodiment 1. As shown in Figures 2, 3, 6, and 7, the negative electrode current collector plate 30N is located inside the case 20. The negative electrode current collector plate 30N is located on one side of the wound electrode body 10 in the axial direction Z, 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 plate 30N is joined to the unpainted negative electrode portion 111NB of the negative electrode 11N by welding. As a result, the negative electrode current collector plate 30N is negatively charged. The negative electrode current collector plate 30N is joined to the cylindrical wall portion 22 by crimping it together with the outer edge of the sealing plate 23 and the annular gasket 27 at the crimp 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 pieces 34N, and a plurality of second pieces 35N. In Embodiment 1, the above-mentioned components included in the negative electrode current collector plate 30N are exemplified as the central portion (31), outer peripheral edge portion (32), spokes (33), first piece (34), and second piece (35) in this disclosure. 【0065】 The central portion 31N is positioned so as to coincide with 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 coincide with the winding axis α when viewed from the axial direction Z. The central portion 31N may be in contact with the uncoated portion 111NB of the negative electrode 11N. However, the central portion 31N is not joined to the uncoated portion 111NB of the negative electrode. 【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 pour the electrolyte through the through-hole 23h. In addition, when releasing the pressure inside the case 20, it is possible to prevent the negative electrode current collector plate 30N 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 the center. 【0068】 The negative electrode current collector plate 30N is electrically connected to the negative electrode terminal 21N by either the outer peripheral edge 32N or the central portion 31N being connected to the case 20. In this embodiment, the negative electrode current collector plate 30N is electrically connected to the negative electrode terminal 21N by the outer peripheral edge 32N being connected to the cylindrical wall portion 22. Specifically, the outer peripheral edge 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 32N is electrically connected to the negative electrode terminal 21N which is 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 in an annular shape from the central portion 31N. The annular base portion 321 is not connected to the cylindrical wall portion 22. That is, the annular base portion 321 is not crimped to the cylindrical wall portion 22 by the crimping portion 22d. 【0070】 Each of the multiple outermost portions 322 extends outward from the annular base 321. The multiple outermost portions 322 are spaced apart from each other. The multiple outermost portions 322 are arranged at equal intervals in the circumferential direction with respect to the central portion 31P. The multiple outermost portions 322 are connected to the cylindrical wall portion 22. That is, the multiple outermost portions 322 are crimped to the cylindrical wall portion 22 by crimping portions 22d. By connecting the multiple outermost portions 322 and the cylindrical wall portion 22, which are spaced apart from each other, by crimping, stress concentration on the outer edge portion 32N can be alleviated. 【0071】 Multiple spokes 33N are spaced apart from each other. Multiple spokes 33N are arranged at equal intervals in the circumferential direction with respect to the central portion 31N. The spokes 33N connect the central portion 31N and the outer peripheral portion 32N. The spokes 33N have an outer diameter such that the width dimension is approximately equal from the central portion 31N to the outer peripheral portion 32N. Each of the multiple spokes 33N is aligned with multiple outermost portions 322 in the radial direction. This makes it possible to suppress the shear force acting between the annular base portion 321 and the outermost portion 322 when the spokes 33N bend in one direction of the axial direction Z. 【0072】 The multiple first pieces 34N are spaced apart from each other. The multiple first pieces 34N are arranged at equal intervals in the circumferential direction with respect to the central piece 31N. Each of the multiple first pieces 34N is adjacent to two spokes 33N on each side in the circumferential direction. 【0073】 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 unpainted negative electrode portion 111NB of the negative electrode 11N by welding. Figures 6 and 7 schematically show the first path PN1, which is the path on the negative electrode current collector plate 30N from the joint between the first piece 34N and the unpainted negative electrode portion 111NB to the joint between the outer peripheral edge portion 32N and the cylindrical wall portion 22. The first piece 34N extends along two adjacent spokes 33N. This makes the surface area of ​​the first piece 34N relatively large, facilitating welding to the unpainted negative electrode portion 111NB of the negative electrode 11N. 【0074】 The multiple second pieces 35N are spaced apart from each other. The multiple second pieces 35N are arranged at equal intervals in the circumferential direction with respect to the central piece 31N. Each of the multiple second pieces 35N is adjacent to two spokes 33N on each side in the circumferential direction. That is, the first piece 34N and the second pieces 35N are arranged in the circumferential direction with respect to the central piece 31N via the spokes 33N. 【0075】 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 is joined to the unpainted negative electrode portion 111NB of the negative electrode 11N by welding. Figures 6 and 7 schematically show the second path PN2, which is the path on the negative electrode current collector plate 30N from the joint between the second piece 35N and the unpainted negative electrode portion 111NB to the joint between the outer peripheral edge 32 and the cylindrical wall portion 22. Note that the second piece 35N does not necessarily have to be joined to the unpainted negative electrode portion 111NB by welding. 【0076】 The second piece 35N has a fan-shaped portion 351N and a neck portion 352N. The fan-shaped portion 351N is joined to the unpainted negative electrode 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 both sides in the circumferential direction. This makes the surface area of ​​the fan-shaped portion 351N relatively large, facilitating welding to the unpainted negative electrode portion 111NB of the negative electrode 11N. 【0077】 The neck portion 352N connects the outer peripheral edge portion 32N and the fan-shaped portion 351N. The neck portion 352N may be in contact with the uncoated negative electrode portion 111NB of the negative electrode 11N. However, the neck portion 352N is not joined to the uncoated negative electrode 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. This makes it easier for the second piece portion 35N to bend in the neck portion 352N. 【0078】 Here, an example of a method for joining the outermost part 322 of the outer peripheral edge 32N to the cylindrical wall 22 by crimping will be described. First, before the outermost part 322 is joined to the cylindrical wall 22 by crimping, the fan-shaped parts 351N of the first piece 34N and the second piece 35N are welded in advance to the unpainted negative electrode portion 111NB of the negative electrode 11N. After that, the cylindrical wall 22 is crimped to form the crimped portion 22d. At this time, on the first path PN1, 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 32N, bend significantly. As a result, the outermost part 322 can be easily displaced in the axial direction Z relative to the first piece 34N. Therefore, even if the outer peripheral edge 32N is displaced in the axial direction Z when it is connected to the cylindrical wall portion 22, the joint between the first piece 34N and the uncoated negative electrode portion 111NB is prevented from breaking. Consequently, the connection between the negative electrode current collector plate 30N and the case 20 becomes easier. 【0079】 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 the heat generated when energized. 【0080】 As described above, the energy storage cell 1 according to Embodiment 1 of the present disclosure comprises a wound electrode body 10, a case 20, and a current collector plate 30. The wound electrode body 10 includes a first electrode 11A and a second electrode 11B. The case 20 houses the wound electrode body 10 and includes a first external terminal 21A. The current collector plate 30 is located within the case 20 on one side of the wound electrode body 10 in the axial direction Z. 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 edge portion 32, spokes 33, a first piece portion 34, and a second piece portion 35. The central portion 31 is positioned to coincide with 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 periphery side of the central portion 31. The current collector plate 30 is electrically connected to the first external terminal 21A by either the outer edge portion 32 or the central portion 31 being connected to the case 20. The spoke 33 connects the central portion 31 and the outer edge portion 32. The first piece portion 34 extends from the central portion 31 toward the outer edge portion 32 and is connected to the first electrode 11A. The second piece portion 35 extends from the outer edge portion 32 toward the central portion 31 and is connected to the first electrode 11A. 【0081】 According to the above configuration, the connection between the current collector plate 30 and the case 20 is made easier, and the heat generated by the current collector plate 30 can be suppressed. 【0082】 Furthermore, from another perspective, the above configuration allows the energy storage cell 1 to generate a moderate amount of heat when energized. As in Embodiment 1 of this disclosure, for example, when the outer peripheral edge 32 is connected to the case 20, the path PN1 on the current collector plate 30, which consists of the first piece 34, the central part 31, the spoke 33, and the outer peripheral edge 32 in that order, becomes relatively long. Therefore, when the energy storage cell 1 is energized, the current collector plate 30 generates a relatively large amount of heat along the path PN1. On the other hand, the path on the current collector plate 30, which consists only of the second piece 35 and the outer peripheral edge 32, becomes relatively short. Therefore, the amount of heat generated along the path PN2 when energized is relatively small. This makes it possible to provide an energy storage cell 1 that can generate a moderate amount of heat when energized. 【0083】 Furthermore, in Embodiment 1 of the present disclosure, the first piece 34 and the second piece 35 are arranged via spokes 33 in the circumferential direction centered on the central portion 31. 【0084】 According to the above configuration, a long conductive path on the current collector plate 30 that generates relatively large amounts of heat when energized (first path PN1 in this embodiment) and a short path on the current collector plate 30 that generates relatively small amounts of heat (second path PN2 in this embodiment) are arranged circumferentially. This makes it possible to reduce the uneven distribution of heat generated by the current collector plate 30 when energized in the circumferential direction. 【0085】 Furthermore, in Embodiment 1 of this disclosure, the first piece 34 and the second piece 35 are welded to the first electrode 11A. 【0086】 With the above configuration, the first piece 34 and the second piece 35 are securely fixed and connected by the first electrode 11A. Consequently, the conductive path through the first piece 34 (first path PN1 in this embodiment) and the conductive path through the second piece 35 (second path PN2 in this embodiment) in the current collector plate 30 are more reliably formed. 【0087】 Furthermore, in Embodiment 1 of this disclosure, the case 20 includes a cylindrical wall portion 22 that covers the entire outer circumference 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. 【0088】 According to the above configuration, the conductive path from the current collector plate 30 to the first external terminal 21A includes a cylindrical wall portion 22 with a relatively large outer surface area. Therefore, the heat generated when current 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 power storage cell according to Embodiment 2 of this disclosure will be described. In Embodiment 2 of this disclosure, the configuration of the first and second pieces of the negative electrode current collector plate differs from that of Embodiment 1 of this disclosure. Therefore, the same configuration and effects as in Embodiment 1 of this disclosure will not be repeated in this description. 【0090】 Figure 8 is a cross-sectional view showing a storage cell according to Embodiment 2. Figure 9 is a plan view showing the negative electrode current collector plate in Embodiment 2. 【0091】 As shown in Figures 8 and 9, in the energy storage cell 1a according to Embodiment 2 of the present disclosure, the first piece 34a and the second piece 35a are aligned radially with respect to the central portion 31. 【0092】 According to the above configuration, the first piece 34a and the second piece 35a can be arranged compactly. As a result, for example, the number of first pieces 34a and second pieces 35a is greater compared to Embodiment 1. 【0093】 Furthermore, the multiple spokes 33 and multiple first pieces 34a are arranged so that the spokes 33 and first pieces 34a alternate in the circumferential direction centered on the central part 31. The multiple spokes 33 and multiple second pieces 35a are arranged so that the spokes 33 and second pieces 35a alternate in the circumferential direction centered on the central part 31. 【0094】 (Embodiment 3) Next, a power storage cell according to Embodiment 3 of the present disclosure will be described. Embodiment 3 of the present disclosure differs from Embodiment 1 of the present disclosure mainly in that the current collector plate in the present disclosure is exemplified as a positive electrode current collector plate 30P. Therefore, the same configuration and effects as in Embodiment 1 of the present disclosure will not be repeated in the description. 【0095】 Figure 10 is a cross-sectional view of one energy storage cell according to Embodiment 3. Figure 11 is a cross-sectional view of another energy storage cell according to Embodiment 3. Figure 12 is an exploded perspective view showing one energy storage cell according to Embodiment 3. Figure 13 is another exploded perspective view showing one energy storage cell according to Embodiment 3. 【0096】 As shown in Figures 10 to 13, in the energy storage cell 1b according to Embodiment 3 of the present disclosure, a positive electrode 11Pb is exemplified as the first electrode (11Ab) in the present disclosure, and a negative electrode 11Nb is exemplified as the second electrode (11Ab) in the present disclosure. Furthermore, a positive electrode terminal 21Pb is exemplified as the first external terminal (21Ab) in the present disclosure, and a negative electrode terminal 21Nb is exemplified as the second external terminal (21Bb) in the present disclosure. 【0097】 First, the positive electrode current collector plate 30Pb in this embodiment will be described. Figure 14 is a plan view showing the positive electrode current collector plate in Embodiment 3. As shown in Figures 10 to 12 and Figure 14, the positive electrode current collector plate 30Pb is exemplified as the current collector plate (30b) in this disclosure. The central portion (31P), outer edge portion (32P), spoke (33), first piece portion (34b), and second piece portion (35b) in this disclosure are exemplified as the central portion (31P), outer edge portion (32P), spoke (33P), first piece portion (34Pb), and second piece portion (35Pb) included in the positive electrode current collector plate 30P, respectively. 【0098】 In Embodiment 3, the positive electrode current collector plate 30P includes a plurality of first pieces 34Pb and a plurality of second pieces 35Pb. 【0099】 The multiple first pieces 34Pb are spaced apart from each other. The multiple first pieces 34Pb are arranged at equal intervals in the circumferential direction with respect to the central part 31P. Each of the multiple first pieces 34Pb is adjacent to two spokes 33P on each side in the circumferential direction. 【0100】 The first piece 34Pb extends from the central portion 31P toward the outer edge portion 32P. The first piece 34Pb is connected to the positive electrode 11P. Specifically, the first piece 34Pb is joined to the unpainted positive electrode portion 111PB of the positive electrode 11P by welding. Figure 14 schematically shows the first path PP1b, which is the path on the positive electrode current collector plate 30Pb from the joint between the first piece 34Pb and the unpainted positive electrode portion 111PB to the joint between the central portion 31P and the rivet portion 212. The first piece 34Pb extends along two adjacent spokes 33P. This makes the surface area of ​​the first piece 34Pb relatively large, facilitating welding to the unpainted positive electrode portion 111PB of the positive electrode 11P. Furthermore, the first piece 34Pb does not necessarily have to be joined to the uncoated positive electrode portion 111PB by welding. 【0101】 The multiple second pieces 35Pb are spaced apart from each other. The multiple second pieces 35Pb are arranged at equal intervals in the circumferential direction with respect to the central portion 31P. Each of the multiple second pieces 35Pb is adjacent to two spokes 33P on each of its circumferential sides. That is, the first piece 34Pb and the second piece 35Pb are arranged in the circumferential direction with respect to the central portion 31P via the spokes 33P. 【0102】 The second piece 35Pb extends from the outer edge 32P toward the central part 31P. The second piece 35Pb is connected to the positive electrode 11P. The second piece 35Pb is joined to the unpainted positive electrode portion 111PB of the positive electrode 11P by welding. Figure 14 schematically shows the second path PP2b, which is the path on the positive electrode current collector plate 30P from the joint between the second piece 35Pb and the unpainted positive electrode portion 111PB to the joint between the central part 31P and the rivet portion 212. 【0103】 The second piece 35Pb has a fan-shaped portion 351P and a neck portion 352P. The fan-shaped portion 351P is joined to the unpainted positive electrode 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 both sides in the circumferential direction. This makes the surface area of ​​the fan-shaped portion 351P relatively large, facilitating welding to the unpainted positive electrode portion 111PB of the positive electrode 11P. 【0104】 The neck portion 352P connects the outer peripheral edge portion 32P and the fan-shaped portion 351P. The neck portion 352P may be in contact with the uncoated positive electrode portion 111PB of the positive electrode 11P. However, the neck portion 352P is not joined to the uncoated positive electrode 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. This makes it easier for the second piece portion 35Pb to bend at the neck portion 352P. 【0105】 Here, an example of a welding method between 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 piece 34Pb and the second piece 35Pb are welded in advance to the uncoated positive electrode portion 111PB of the positive electrode 11P. Next, a welding device is inserted from the second direction Z2 side of the wound electrode body 10 along the winding axis α of the wound electrode body 10. Then, while the welding device is pressed against the central portion 31P from the second direction Z2 side, the central portion 31P and the rivet portion 212 are welded to each other by the welding device. At this time, on the second path PP2b, 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, bend significantly. As a result, the central portion 31P can be easily displaced in the axial direction Z relative to the second portion 35Pb. Therefore, even if a welding device is pressed against the central portion 31P, the displacement of the central portion 31P prevents the joint between the second portion 35Pb and the uncoated positive electrode portion 111PB from being destroyed. Consequently, the connection between the positive electrode current collector plate 30Pb and the case 20 becomes easier. 【0106】 On the other hand, the first path PP1b is shorter than the second path PP2b. Therefore, when the positive electrode current collector plate 30Pb is energized, the first path PP1b becomes the main conductive path. The relatively short first path PP1b can reduce the heat generated when energized. 【0107】 Next, the negative electrode current collector plate 30Nb in Embodiment 3 will be described. As shown in Figures 10, 11, and 13, in Embodiment 3, the negative electrode current collector plate 30Nb includes a plurality of pieces 34Nb. 【0108】 Multiple side pieces 34Nb are spaced apart from each other. Multiple side pieces 34Nb are arranged at equal intervals in the circumferential direction with respect to the central part 31N. Multiple spokes 33N and multiple side pieces 34Nb are arranged such that the spokes 33N and side pieces 34Nb alternate in the circumferential direction with respect to the central part 31N. 【0109】 The single piece 34Nb extends from the central part 31N toward the outer peripheral edge 32N. The single piece 34Nb is connected to the negative electrode 11N. Specifically, the single piece 34Nb is joined to the unpainted negative electrode portion 111NB of the negative electrode 11N by welding. Figure 13 schematically shows path PNb, which is the path on the negative electrode current collector plate 30N from the joint between the single piece 34Nb and the unpainted negative electrode portion 111NB to the joint between the outer peripheral edge 32N and the cylindrical wall portion 22. The single piece 34Nb extends along two adjacent spokes 33N. This makes the surface area of ​​the single piece 34Nb relatively large, facilitating welding to the unpainted negative electrode portion 111NB of the negative electrode 11N. 【0110】 Here, an example of a method for joining the outermost part 322 of the outer peripheral edge 32N to the cylindrical wall 22 by crimping will be described. First, before the outermost part 322 is joined to the cylindrical wall 22 by crimping, one piece 34Nb is welded in advance to the unpainted negative electrode portion 111NB of the negative electrode 11N. After that, the cylindrical wall 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 32N, bends significantly on the path PNb. As a result, the outermost part 322 can be easily displaced in the axial direction Z relative to the one piece 34Nb. Therefore, even if the outer peripheral edge 32N is displaced in the axial direction Z when it is connected to the cylindrical wall 22, the failure of the joint between the one piece 34Nb and the unpainted negative electrode portion 111NB is suppressed. This, in turn, makes it easier to connect the negative electrode current collector plate 30Nb to the case 20. 【0111】 As described above, the energy storage cell 1b according to Embodiment 3 of the present disclosure comprises a wound electrode body 10, a case 20, and a current collector plate 30b. The wound electrode body 10 includes a first electrode 11Ab and a second electrode 11B. The case 20 houses the wound electrode body 10 and includes a first external terminal 21Ab. The current collector plate 30b is located within the case 20 on one side of the wound electrode body 10 in the axial direction Z. The current collector plate 30b is provided to electrically connect the first electrode 11Ab and the first external terminal 21Ab. The current collector plate 30b includes a central portion 31, an outer peripheral edge portion 32, spokes 33, a first piece portion 34b, and a second piece portion 35b. The central portion 31 is positioned to coincide with 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 periphery side of the central portion 31. The current collector plate 30b is electrically connected to the first external terminal 21Ab by either the outer peripheral edge portion 32 or the central portion 31 being connected to the case 20. The spoke 33 connects the central portion 31 and the outer peripheral edge portion 32. The first piece portion 34b extends from the central portion 31 toward the outer peripheral edge portion 32 and is connected to the first electrode 11Ab. The second piece portion 35b extends from the outer peripheral edge portion 32 toward the central portion 31 and is connected to the first electrode 11Ab. 【0112】 According to the above configuration, the connection between the current collector plate 30b and the case 20 is made easier, and the heat generated by the current collector plate 30b can be suppressed. 【0113】 Furthermore, from another perspective, the above configuration allows the energy storage cell 1b to generate a moderate amount of heat when energized. As in Embodiment 3 of this disclosure, for example, when the central portion 31 is connected to the case 20, the path PP2b on the current collector plate 30b, which consists of the second piece portion 35b, the outer edge portion 32, the spoke 33, and the central portion 31 in that order, becomes relatively long. Therefore, when the energy storage cell 1b is energized, the current collector plate 30b generates a relatively large amount of heat on the path PP2b. On the other hand, the path PP1b on the current collector plate 30b, which consists only of the first piece portion 34b and the central portion 31, becomes relatively short. Therefore, the amount of heat generated on the path PP1b when energized is relatively small. This makes it possible to provide an energy storage cell 1b that can generate a moderate amount of heat when energized. 【0114】 Furthermore, in Embodiment 3 of the present disclosure, the first piece 34b and the second piece 35b are arranged via spokes 33 in the circumferential direction centered on the central portion 31. 【0115】 According to the above configuration, a long conductive path on the current collector plate 30b that generates relatively large amounts of heat when energized (the second path PP2b in this embodiment) and a short path on the current collector plate 30b that generates relatively short amounts of heat (the first path PP1b in this embodiment) are arranged relative to each other in the circumferential direction. This makes it possible to reduce the bias in the distribution of heat generated by the current collector plate 30b when energized in the circumferential direction. 【0116】 Furthermore, in Embodiment 3 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 piece 34b and the second piece 35b are securely fixed and connected by the first electrode 11Ab. Consequently, the conductive path via the first piece 34b (first path PP1b in this embodiment) and the conductive path via the second piece 35b (second path PP2b in this embodiment) in the current collector plate 30b are more reliably formed. 【0118】 Furthermore, in Embodiment 3 of this disclosure, the first external terminal 21Ab is positioned so as to overlap with the central portion 31 when viewed from the axial direction Z. Also, the central portion 31 is connected to the case 20, thereby electrically connecting the current collector plate 30b 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 power storage cell according to Embodiment 4 of this disclosure will be described. In Embodiment 4 of this disclosure, the first and second pieces of the positive electrode current collector plate differ from those in Embodiment 3 of this disclosure. Therefore, the same configuration and effects as in Embodiment 3 of this disclosure will not be repeated in the description. 【0121】 Figure 15 is a plan view showing a power storage cell according to Embodiment 4. Figure 16 is a plan view showing a positive electrode current collector plate in Embodiment 4. 【0122】 As shown in Figures 15 and 16, in the energy storage cell 1c according to Embodiment 4 of the present disclosure, the first piece 34c and the second piece 35c are aligned radially with respect to the central portion 31. 【0123】 According to the above configuration, the first piece 34c and the second piece 35c can be arranged compactly. As a result, for example, the number of first piece 34c and second piece 35c is greater compared to Embodiment 3. 【0124】 Furthermore, the multiple spokes 33 and multiple first pieces 34c are arranged so that the spokes 33 and first pieces 34c alternate in the circumferential direction centered on the central part 31. The multiple spokes 33 and multiple second pieces 35c are arranged so that the spokes 33 and second pieces 35c alternate in the circumferential direction centered on the central part 31. 【0125】 (Embodiment 5) Next, a power storage cell according to Embodiment 5 of this disclosure will be described. Embodiment 5 of this disclosure differs from power storage cell 1b according to Embodiment 3 of this disclosure in that a negative electrode current collector plate is not provided. Therefore, the same configuration and effects as those of Embodiment 3 of this disclosure will not be repeated in the description. 【0126】 Figure 17 is a cross-sectional view of the energy storage cell according to Embodiment 5. Figure 18 is an exploded perspective view showing the energy storage cell according to Embodiment 5 in an exploded state. 【0127】 As shown in Figures 17 and 18, in the energy storage cell 1d according to Embodiment 5, the case 20 does not include an annular gasket. 【0128】 In this embodiment, the outer 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 crimping 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 uncoated negative electrode portion 111NB of the negative electrode 11N by welding. As a result, the sealing plate 23d is negatively charged. The negative electrode terminal 21N, which is connected to the cylindrical wall portion 22, is also negatively charged. Note that the sealing plate 23d may also be the negative electrode terminal. 【0130】 The sealing plate 23d has an annular projection 231, a plurality of radial projections 232, and a plurality of welded parts 233. The annular projection 231 extends in an annular shape around the winding axis α of the wound electrode body 10 when viewed from the axial direction Z. The annular projection 231 protrudes toward the first direction Z1. That is, the annular projection 231 protrudes toward the wound electrode body 10. The annular projection 231 is in contact with the uncoated negative electrode portion 111NB of the negative electrode 11N. 【0131】 The multiple radial protrusions 232 are arranged 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 protrusions 232 are arranged at equal intervals in the circumferential direction. 【0132】 Each of the multiple radially oriented protrusions 232 extends radially around the winding axis α of the wound electrode body 10. The radially oriented protrusions 232 are connected to the annular protrusions 231. 【0133】 The radially protruding portion 232 protrudes toward the first direction Z1. That is, the radially protruding portion 232 protrudes toward the wound electrode body 10. The radially protruding portion 232 is in contact with the uncoated portion 111NB of the negative electrode 11N. 【0134】 Multiple welds 233 are portions of the sealing plate 23d that are joined to the uncoated negative electrode portion 111NB by welding. Multiple welds 233 are formed on the annular protrusion 231. On the annular protrusion 231, multiple welds 233 are formed to extend along the circumferential direction. Multiple welds 233 are formed on each of the multiple radial protrusions 232. On the radial protrusions 232, multiple welds 233 are formed to extend along the radial direction. The annular protrusion 231 and the multiple radial protrusions 232 may be thinner than other parts of the sealing plate 23d. This facilitates the formation of the welds 233. 【0135】 In the above-described embodiments, the combinatable configurations may be combined with each other. For example, it is possible to combine the positive electrode current collector plate in one embodiment with the negative electrode current collector plate in another embodiment. 【0136】 The embodiments disclosed herein should be considered in all respects to be illustrative and not restrictive. The scope of this disclosure is indicated by the claims rather than by the description of the embodiments above, and all modifications within the meaning and scope equivalent to the claims are intended to be included. [Explanation of Symbols] 【0137】 1,1a,1b,1c,1d Energy storage cell, 10 Winding electrode body, 11A,11Ab First electrode, 11B,11Bb Second electrode, 11P,11Pb Positive electrode, 111PA Coated positive electrode section, 111PB Uncoated positive electrode section, 111PC,111NC Extension section, 112P Positive electrode composite layer, 11N,11Nb Negative electrode, 111N Negative electrode current collector, 111NA Negative electrode coated section, 111NB Negative electrode uncoated section, 111P 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 Disc section, 212 Rivet section, 21N, 21Nb Negative terminal, 22 Cylindrical wall section, 22d Crimped section, 23, 23d Sealing plate, 231 Annular protrusion section, 232 Radial protrusion section, 233 Welded section, 24 Sealing plug, 25 External gasket, 26 Internal gasket, 27 Annular gasket, 30, 30b Current collector plate, 30N, 30Nb Negative current collector plate, 30P, 30Pb Positive current collector plate, 31, 31N, 31P Central section, 32, 32N, 32P Outer edge section, 321 Annular base section, 322 Outermost section, 33, 33N, 33P Spoke, 34Nb, 35P Side section, 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

[Claim 1] A wound electrode body including a first electrode and a second electrode, A case for housing the aforementioned wound electrode body, The case comprises a current collector plate positioned on one side in the axial direction of the wound electrode body, The case further includes a cylindrical wall portion, an annular gasket, and a sealing plate. The cylindrical wall portion is located on the outer circumference side of the wound electrode body. A crimped portion is formed at the end of the cylindrical wall portion. The annular gasket is located between the crimped portion and the outer edge of the sealing plate. The aforementioned current collector plate is The central part, Outer edge and, Spokes and, Including a part, A through hole is formed in the central part, The aforementioned outer peripheral edge is located on the outer peripheral side of the central portion. The outer peripheral edge is connected to the crimped portion, The spokes connect the central portion and the outer peripheral edge portion. The aforementioned piece extends from the outer peripheral edge toward the central portion when viewed from the axial direction and is connected to the first electrode. A storage cell in which the spokes are bent in a concave manner toward the sealing plate and connected to the sealing plate. [Claim 2] The aforementioned outer peripheral edge includes an annular base and a plurality of outermost peripheral portions. Each of the aforementioned plurality of outermost portions extends outward from the annular base, The aforementioned multiple outermost parts are spaced apart from each other. The energy storage cell according to claim 1, wherein the plurality of outermost portions are connected to the crimped portion. [Claim 3] The aforementioned piece includes a fan-shaped portion and a neck portion, The fan-shaped portion is joined to the first electrode by welding. The neck portion connects the outer peripheral edge portion and the fan-shaped portion. The energy storage cell according to claim 1 or claim 2, wherein the dimension of the neck portion in the circumferential direction of the outer peripheral edge is smaller than the dimension of the fan-shaped portion in the circumferential direction. [Claim 4] The aforementioned piece includes a neck portion connected to the outer peripheral edge and an inner peripheral edge located opposite the neck portion. The energy storage cell according to claim 1 or claim 2, wherein the inner periphery extends in an arc shape so as to be concave toward the neck portion. [Claim 5] The aforementioned sealing plate has through holes connected to it. The case further includes a sealing plug that seals the through hole formed in the sealing plate, The energy storage cell according to claim 1 or claim 2, wherein the inner space of the through hole formed in the central part and the inner space of the through hole formed in the sealing plate are aligned in the axial direction.

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