Energy storage cell

Abstract

To suppress a short circuit in an internal part of a cell case 20.SOLUTION: In a power storage cell 1 based on the present disclosure, a winding electrode body 10 contains: a first electrode 11P; and a second electrode 11N. A first collector member 30 is connected to the first electrode 11P. A second collector member 40 is connected to the second electrode 11N. A lid 22 contains: a first external terminal 221P; and a second external terminal 221N. The first external terminal 221P is arranged so as to be overlapped with a radial direction center of the winding electrode body 10 in view of a shaft direction Z. The second external terminal 221N is fixed to a case main body 21. The first collector member 30 is connected to the first external terminal 221P. The second collector member 40 is arranged between the case main body 21 and the second external terminal 221N. The second collector member 40 is connected to the second external terminal 221N so as to be fixed to the case main body 21 with the second external terminal 221N.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present disclosure relates to a storage battery cell.

Background Art

[0002] Patent Document 1 discloses a conventional non-aqueous electrolyte secondary battery as a storage battery cell. In this non-aqueous electrolyte secondary battery, a negative electrode and a positive electrode are wound through a porous separator and inserted into a cylindrical container. Leads are taken out from the positive electrode and the negative electrode. The cylindrical container is made of stainless steel. A container lid is welded to the opening of the container at the peripheral edge. Positive and negative terminals are provided at a part of the container lid.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] When both a positive terminal and a negative terminal are provided on the lid as in the storage battery cell disclosed in Patent Document 1, the distance between the positive lead and the negative lead inside the container becomes relatively short. As a result, for example, there is a risk that the leads may contact each other and cause a short circuit.

[0005] The present disclosure has been made in view of the above problems, and an object thereof is to provide a storage battery cell capable of suppressing a short circuit inside a cell case.

Means for Solving the Problems

[0006] A storage cell according to the first aspect of this disclosure comprises a wound electrode body, a cell case, a first current collector member, and a second current collector member. The wound electrode body includes a first electrode and a second electrode. The cell case houses the wound electrode body. The first current collector member is connected to the first electrode. The second current collector member is connected to the second electrode. The cell case includes a case body and a lid. The case body has an opening that opens on one side in the axial direction of the wound electrode body when viewed from the wound electrode body. The lid closes the opening of the case body. The lid includes a first external terminal and a second external terminal. The first external terminal is positioned to coincide with the radial center of the wound electrode body when viewed from the axial direction. The second external terminal is fixed to the case body. The first current collector member is positioned on the one side in the axial direction of the wound electrode body. The first current collector member is connected to the first external terminal. The second current collector is positioned on one side of the wound electrode body in the axial direction. The second current collector is positioned between the case body and the second external terminal. The second current collector is joined to the second external terminal by being fixed to the case body together with the second external terminal.

[0007] According to the above configuration, the second external terminal and the second current collector are joined to each other at a position relatively far from the first current collector connected to the first external terminal. Therefore, short circuits between the first current collector and the second current collector can be suppressed. Accordingly, according to the above configuration, it is possible to provide a power storage cell in which short circuits inside the cell case are suppressed.

[0008] A storage cell according to a second aspect of the present disclosure comprises a wound electrode body, a cell case, a first current collector member, and a second current collector member. The wound electrode body includes a first electrode and a second electrode. The cell case houses the wound electrode body. The first current collector member is connected to the first electrode. The second current collector member is connected to the second electrode. The cell case includes a case body and a lid. The case body is conductive and has an opening that opens on one side of the wound electrode body in the axial direction when viewed from the wound electrode body. The lid closes the opening of the case body. The lid includes a first external terminal and a second external terminal. The first external terminal is positioned to coincide with the radial center of the wound electrode body when viewed from the axial direction. The second external terminal is directly bonded to the case body. The first current collector member is positioned on the one side of the wound electrode body in the axial direction. The first current collector is connected to the first external terminal. The second current collector is located on the other side of the wound electrode body in the axial direction. The second current collector is directly connected to the case body.

[0009] According to the above configuration, the second external terminal and the second current collector are electrically connected to each other via the case body at a position relatively far from the first current collector connected to the first external terminal. Therefore, short circuits between the first current collector and the second current collector can be suppressed. Accordingly, according to the above configuration, it is possible to provide a power storage cell in which short circuits inside the cell case are suppressed. [Effects of the Invention]

[0010] According to this disclosure, short circuits inside the cell case can be suppressed. [Brief explanation of the drawing]

[0011] [Figure 1] This is a perspective view showing a storage cell according to Embodiment 1. [Figure 2] Figure 1 is a cross-sectional view of the energy storage cell as seen in the direction of the arrow along line II-II. [Figure 3] This is a cross-sectional view showing a storage cell according to Embodiment 2. [Modes for carrying out the invention]

[0012] 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.

[0013] (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, viewed in the direction of the arrow line II-II.

[0014] As shown in Figures 1 and 2, the energy storage cell 1 according to Embodiment 1 is a cylindrical battery. The energy storage cell 1 comprises a wound electrode body 10, a cell case 20, a first current collector 30, and a second current collector 40.

[0015] First, the wound electrode body 10 will be described. As shown in Figure 2, 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.

[0016] In Embodiment 1, a positive electrode 11P is exemplified as the first electrode in this disclosure. In Embodiment 1, a negative electrode 11N is exemplified as the second electrode in this disclosure. However, the first electrode may be a negative electrode. The second electrode may be a positive electrode.

[0017] 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.

[0018] 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.

[0019] The positive electrode 11P includes a positive electrode current collector foil 111P and a positive electrode composite material layer 112P. The positive electrode current collector foil 111P is formed of, for example, aluminum or the like.

[0020] The positive electrode composite material layer 112P is coated on both radial surfaces of the positive electrode current collector foil 111P. The positive electrode composite material layer 112P is in close contact with the separator 12. The positive electrode composite material layer 112P is formed by coating a positive electrode slurry on the surface of the positive electrode current collector foil 111P and drying it. The positive electrode slurry is a slurry prepared by kneading the materials (such as positive electrode active material and binder) of the positive electrode composite material layer 112P and a solvent. The thickness of the positive electrode composite material layer 112P is, for example, 0.1 μm or more and 1000 μm or less.

[0021] The negative electrode 11N includes a negative electrode current collector foil 111N and a negative electrode composite material layer 112N. The negative electrode current collector foil 111N is formed of, for example, copper or the like.

[0022] The negative electrode composite material layer 112N is coated on both radial surfaces of the negative electrode current collector foil 111N. The negative electrode composite material layer 112N is in close contact with the separator 12. The negative electrode composite material layer 112N is formed by coating a negative electrode slurry on the surface of the negative electrode current collector foil 111N and drying it. The negative electrode slurry is a slurry prepared by kneading the materials (such as negative electrode active material and binder) of the negative electrode composite material layer 112N and a solvent. The thickness of the negative electrode composite material layer 112N is, for example, 0.1 μm or more and 1000 μm or less.

[0023] Next, the cell case 20 will be described. As shown in FIGS. 1 and 2, the cell case 20 houses the wound electrode body 10. The cell case 20 includes a case body 21 and a lid 22.

[0024] The case body 21 has an opening 211 that opens on one side (the first direction Z1 side) in the axial direction Z of the wound electrode body 10 when viewed from the wound electrode body 10. Specifically, the opening 211 opens on the first direction Z1 side of the case body 21. The case body 21 has a bottomed cylindrical outer shape.

[0025] The case body 21 further includes a crimped portion 212 formed by crimping the end of one side (first direction Z1 side) of the wound electrode body 10. The crimped portion 212 extends in an annular shape along the opening 211.

[0026] The case body 21 further includes a cylindrical wall portion 213, a bottom portion 214, and a sealing layer 215.

[0027] The cylindrical wall portion 213 is provided to cover the outer circumference of the wound electrode body 10. The cylindrical wall portion 213 covers the entire outer circumference of the wound electrode body 10. The cylindrical wall portion 213 has a cylindrical shape. The cylindrical wall portion 213 may have a rectangular cylindrical outer shape. The cylindrical wall portion 213 is located in the second direction Z2 in the axial direction Z when viewed from the crimping portion 212. The cylindrical wall portion 213 is integrally molded with the crimping portion 212.

[0028] The bottom portion 214 is positioned in the second direction Z2, which is along the axial direction Z, when viewed from the wound electrode body 10. The bottom portion 214 is connected to the end of the cylindrical wall portion 213 on the second direction Z2 side. In this embodiment, the bottom portion 214 is formed integrally with the cylindrical wall portion 213. The bottom portion 214 may be molded as a separate component from the cylindrical wall portion 213. In this case, the outer peripheral edge of the bottom portion 214 may be joined to the cylindrical wall portion 213 by laser welding or the like.

[0029] A through-hole 214h is formed in the bottom portion 214. The through-hole 214h may be provided for injecting electrolyte (not shown) contained within the cell case 20. A sealing plug 216 is inserted through the through-hole 214h of the bottom portion 214. This fixes the sealing plug 216 to the bottom portion 214. The sealing plug 216 and the through-hole 214h can function as pressure relief valves to release the pressure inside the cell case 20 when the pressure inside the cell case 20 becomes excessively high.

[0030] The crimped portion 212, the cylindrical wall portion 213, and the bottom portion 214 are electrically conductive. The crimped portion 212, the cylindrical wall portion 213, and the bottom portion 214 are made of aluminum or an aluminum alloy, copper, or stainless steel.

[0031] The sealing layer 215 is positioned radially inward of the crimped portion 212. In this embodiment, the sealing layer 215 forms the opening 211. The sealing layer 215 extends along the crimped portion 212. The sealing layer 215 has an annular outer shape. The sealing layer 215 has electrical insulating properties.

[0032] The lid 22 closes the opening 211 of the case body 21. The lid 22 includes a positive external terminal 221P, a negative external terminal 221N, and an insulating member 222. In Embodiment 1, the positive external terminal 221P is exemplified as the first external terminal in this disclosure. In Embodiment 1, the negative external terminal 221N is exemplified as the second external terminal in this disclosure. However, the first external terminal may be a negative external terminal, or the second external terminal may be a positive external terminal.

[0033] The positive electrode external terminal 221P is positioned so as to coincide with the radial center of the wound electrode body 10 when viewed from the axial direction Z. The positive electrode external terminal 221P is made of, for example, aluminum, copper, or stainless steel.

[0034] The positive electrode external terminal 221P is located on the first direction Z1 side of the wound electrode body 10. The positive electrode external terminal 221P includes a disk portion 221PA and a rivet portion 221PB.

[0035] The disk portion 221PA is exposed to the outside. The disk portion 221PA is located opposite the wound electrode body 10 when viewed from the negative electrode external terminal 221N.

[0036] The rivet portion 221PB is connected to the disk portion 221PA. The rivet portion 221PB extends from the center of the disk portion 221PA when viewed from the axial direction Z. The rivet portion 221PB is located approximately on the winding axis α of the winding electrode body 10. The rivet portion 221PB extends in the second direction Z2 when viewed from the disk portion 221PA.

[0037] The negative electrode external terminal 221N has a plate-like outer shape. Specifically, the negative electrode external terminal 221N has a roughly circular disc-like outer shape. The negative electrode external terminal 221N is positioned perpendicular to the axial direction Z. The negative electrode external terminal 221N is provided with a through hole 221Nh. Therefore, the negative electrode external terminal 221N has an annular outer shape when viewed from the axial direction Z. The rivet portion 221PB of the positive electrode external terminal 221P is inserted through the through hole 221Nh. As a result, the rivet portion 221PB extends into the interior of the cell case 20.

[0038] The negative external terminal 221N is made of aluminum or an aluminum alloy, copper, or stainless steel.

[0039] The negative external terminal 221N is fixed to the case body 21. Details of how the negative external terminal 221N is fixed to the case body will be described later.

[0040] The first current collector 30 is connected to the positive electrode 11P. Specifically, the first current collector 30 is provided so as to protrude from the positive electrode current collector foil 111P of the positive electrode 11P to one side in the axial direction Z (the first direction Z1 side). For this reason, the first current collector 30 is positioned on the aforementioned one side in the axial direction Z (the first direction Z1 side) of the wound electrode body 10.

[0041] The first current collector 30 is connected to the positive electrode external terminal 221P. Specifically, the first current collector 30 is joined to the rivet portion 221PB of the positive electrode external terminal 221P by welding.

[0042] The first current collector 30 has a tab-lead shape, but the shape of the first current collector 30 is not particularly limited. The first current collector 30 may be a plate-shaped member extending in a plane direction perpendicular to the axial direction Z. The first current collector 30 is conductive. The material constituting the first current collector 30 is not particularly limited. The first current collector 30 may include metal contained in the positive electrode current collector foil 111P or the positive electrode external terminal 221P.

[0043] The second current collector 40 is connected to the negative electrode 11N. Specifically, the second current collector 40 is provided so as to protrude from the negative electrode current collector foil 111N of the negative electrode 11N on one side in the axial direction Z (the first direction Z1 side). For this reason, the second current collector 40 is positioned on the aforementioned one side in the axial direction Z (the first direction Z1 side) of the wound electrode body 10.

[0044] The second current collector 40 is positioned between the case body 21 and the negative electrode external terminal 221N. The second current collector 40 is joined to the negative electrode external terminal 221N by being fixed to the case body 21 together with the negative electrode external terminal 221N. Specifically, the second current collector 40 is fixed to the crimped portion 212 together with the negative electrode external terminal 221N. In other words, the second current collector 40 is fixed to the case body 21 by being crimped together with the negative electrode external terminal 221N.

[0045] More specifically, the sealing layer 215 is positioned between the negative electrode external terminal 221N and the second current collector 40 and the crimped portion 212. The sealing layer 215 is provided to cover the outer periphery of the negative electrode external terminal 221N and the end of the second current collector 40 opposite to the negative electrode 11N side.

[0046] The second current collector 40 has a tab-lead shape, but the shape of the second current collector 40 is not particularly limited. The second current collector 40 may be a plate-shaped member extending in a plane direction perpendicular to the axial direction Z. The second current collector 40 is conductive. The material constituting the second current collector 40 is not particularly limited. The second current collector 40 may contain metal included in the negative electrode current collector foil 111N or the negative electrode external terminal 221N.

[0047] The energy storage cell 1 according to this embodiment may further include a first internal insulating member 50, a second internal insulating member 60, and a third internal insulating member 70.

[0048] The first internal insulating member 50 is provided on the inner surface of the negative electrode external terminal 221N. The first internal insulating member 50 is provided between the negative electrode external terminal 221N and the first current collector member 30. The first internal insulating member 50 is provided to insulate the negative electrode external terminal 221N from the first current collector member 30.

[0049] The second internal insulating member 60 is housed in the cell case 20. The second internal insulating member 60 is provided on the first direction Z1 side of the wound electrode body 10. In the axial direction Z, the second internal insulating member 60 is positioned between the wound electrode body 10 and the crimped portion 212. The second internal insulating member 60 has a first through hole 61 and a second through hole 62. The first current collector member 30 is inserted through the first through hole 61. The second current collector member 40 is inserted through the second through hole 62.

[0050] The third internal insulating member 70 is housed in the cell case 20. The third internal insulating member 70 is provided on the second direction Z2 side of the wound electrode body 10. The third internal insulating member 70 is provided between the bottom portion 214 and the wound electrode body 10. The third internal insulating member 70 is provided to insulate the bottom portion 214 from the wound electrode body 10.

[0051] As described above, the energy storage cell 1 according to Embodiment 1 of the present disclosure comprises a wound electrode body 10, a cell case 20, a first current collector member 30, and a second current collector member 40. The wound electrode body 10 includes a positive electrode 11P (first electrode) and a negative electrode 11N (second electrode). The cell case 20 houses the wound electrode body 10. The first current collector member 30 is connected to the positive electrode 11P. The second current collector member 40 is connected to the negative electrode 11N. The cell case 20 includes a case body 21 and a lid 22. The case body 21 has an opening 211 that opens on one side of the wound electrode body 10 in the axial direction Z when viewed from the wound electrode body 10. The lid 22 closes the opening 211 of the case body 21. The cover 22 includes a positive external terminal 221P (first external terminal) and a negative external terminal 221N (second external terminal). The positive external terminal 221P is positioned so as to coincide with the radial center of the wound electrode body 10 when viewed from the axial direction Z. The negative external terminal 221N is fixed to the case body 21. The first current collector member 30 is positioned on the one side of the wound electrode body 10 in the axial direction Z. The first current collector member 30 is connected to the positive external terminal 221P. The second current collector member 40 is positioned on the one side of the wound electrode body 10 in the axial direction Z. The second current collector member 40 is positioned between the case body 21 and the negative external terminal 221N. The second current collector member 40 is fixed to the case body 21 together with the negative external terminal 221N and is thus joined to the negative external terminal 221N.

[0052] According to the above configuration, the negative external terminal 221N (second external terminal) and the second current collector 40 are joined to each other at a position relatively far from the first current collector 30 which is connected to the positive external terminal 221P (first external terminal). Therefore, short circuits between the first current collector 30 and the second current collector 40 can be suppressed. Accordingly, according to the above configuration, it is possible to provide a power storage cell 1 in which short circuits inside the cell case 20 are suppressed.

[0053] Furthermore, in this embodiment, the case body 21 further includes a crimped portion 212 formed by crimping the end of one side of the wound electrode body 10. The second current collector member 40 is fixed to the crimped portion 212 together with the negative electrode external terminal 221N (second external terminal).

[0054] When the case body 21 is connected to the lid 22 by welding, there is a possibility that foreign matter may enter the cell case 20. However, with the above configuration, the entry of foreign matter into the cell case 20 is suppressed compared to when the case body 21 is connected to the lid 22 by welding. Therefore, with the above configuration, it is possible to provide a storage cell 1 in which short circuits inside the cell case 20 are further suppressed.

[0055] Furthermore, in this embodiment, the case body 21 further includes an electrically insulating sealing layer 215 disposed between the negative electrode external terminal 221N (second external terminal) and the second current collector member 40 and the crimped portion 212.

[0056] According to the above configuration, it is possible to prevent a short circuit between the negative external terminal 221N (second external terminal) and the positive electrode 11P (first electrode) or a component electrically connected to the positive electrode 11P via the case body 21.

[0057] (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 second current collector differs mainly 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.

[0058] Figure 3 is a cross-sectional view showing a storage cell according to Embodiment 2. As shown in Figure 3, in Embodiment 2, the case body 21a does not include the crimped portion and sealing layer shown in Embodiment 1. The end of the cylindrical wall portion 213a on the first direction Z1 side forms an opening 211. In this embodiment, the case body 21a is conductive overall.

[0059] The negative electrode external terminal 221Na is directly joined to the case body 21a. The negative electrode external terminal 221Na is directly joined to the opening 211 of the case body 21a (cylindrical wall portion 213a). The negative electrode external terminal 221Na is joined to the case body 21a by welding. The negative electrode external terminal 221Na is joined to the opening 211 of the case body 21a (cylindrical wall portion 213a) by welding. A welded joint 217 is formed between the negative electrode external terminal 221Na and the case body 21a (cylindrical wall portion 213a).

[0060] The second current collector member 40a is provided so as to protrude from the negative electrode current collector foil 111N of the negative electrode 11N toward the other side in the axial direction Z (the second direction Z2 side). For this reason, the second current collector member 40a is positioned toward the other side in the axial direction Z (the second direction Z2 side) of the wound electrode body 10.

[0061] The second current collector 40a is directly connected to the case body 21a. The second current collector 40a may be joined to the case body 21a by welding or other means. The second current collector 40a is connected to the bottom 214. The second current collector 40a may be connected to the cylindrical wall portion 213a. The second current collector 40a may be connected to both the bottom 214 and the cylindrical wall portion 213a.

[0062] In this embodiment, the second internal insulating member 60a does not necessarily have a second through-hole as shown in Embodiment 1. On the other hand, the third internal insulating member 70a has a third through-hole 71. The second current collector member 40a is inserted through the third through-hole 71.

[0063] As described above, the energy storage cell 1a according to Embodiment 2 of the present disclosure comprises a wound electrode body 10, a cell case 20, a first current collector member 30, and a second current collector member 40a. The wound electrode body 10 includes a positive electrode 11P (first electrode) and a negative electrode 11N (second electrode). The cell case 20 houses the wound electrode body 10. The first current collector member 30 is connected to the positive electrode 11P. The second current collector member 40a is connected to the negative electrode 11N. The cell case 20 includes a case body 21a and a lid 22. The case body 21a is conductive and has an opening 211 that opens on one side of the wound electrode body 10 in the axial direction Z when viewed from the wound electrode body 10. The lid 22 closes the opening 211 of the case body 21a. The cover 22 includes a positive external terminal 221P (first external terminal) and a negative external terminal 221Na (second external terminal). The positive external terminal 221P is positioned to coincide with the radial center of the wound electrode body 10 when viewed from the axial direction Z. The negative external terminal 221Na is directly bonded to the case body 21a. The first current collector 30 is positioned on one side of the wound electrode body 10 in the axial direction Z. The first current collector 30 is connected to the positive external terminal 221P. The second current collector 40a is positioned on the other side of the wound electrode body 10 in the axial direction Z. The second current collector 40a is directly connected to the case body 21a.

[0064] According to the above configuration, the negative external terminal 221Na (second external terminal) and the second current collector 40a are electrically connected to each other via the case body 21a at a position relatively far from the first current collector 30 connected to the positive external terminal 221P (first external terminal). Therefore, short circuits between the first current collector 30 and the second current collector 40a can be suppressed. Accordingly, according to the above configuration, it is possible to provide a power storage cell 1a in which short circuits inside the cell case 20 are suppressed.

[0065] Furthermore, in this embodiment, the negative electrode external terminal 221Na (second external terminal) is joined to the case body 21a by welding.

[0066] With the above configuration, the distance between the wound electrode body 10 and the lid 22 can be reduced compared to the case where the negative electrode external terminal 221Na (second external terminal) is joined by crimping the case body 21a. Therefore, the energy density of the energy storage cell 1a can be improved.

[0067] In the descriptions of each embodiment described above, the combinable configurations may be combined with each other.

[0068] 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]

[0069] 1,1a Energy storage cell, 10 Winded electrode body, 11N Negative electrode, 111N Negative electrode current collector foil, 112N Negative electrode composite layer, 11P Positive electrode, 111P Positive electrode current collector foil, 112P Positive electrode composite layer, 12 Separator, 20 Cell case, 21,21a Case body, 211 Opening, 212 Crimping part, 213,213a Cylindrical wall part, 214 Bottom part, 215 Seal layer, 216 Sealing plug, 217 Welded part, 22 Lid, 221N,221Na Negative electrode external terminal, 221P Positive electrode external terminal, 221PA Disc part, 221PB Rivet part, 222 Insulating member, 30 First current collector member, 40,40a Second current collector member, 50 First internal insulating member, 60,60a Second internal insulating member, 61 first through hole, 62 second through hole, 70, 70a third internal insulating member, 71 third through hole.

Claims

1. A wound electrode body including a first electrode and a second electrode, A cell case for housing the aforementioned wound electrode body, A first current collector connected to the first electrode, The device comprises a second current collector connected to the second electrode, The aforementioned cell case includes a case body and a lid. The case body has an opening that, when viewed from the wound electrode body, opens on one side in the axial direction of the wound electrode body. The case body further includes a crimped portion and a cylindrical wall portion, The crimping portion extends in an annular shape along the opening, The cylindrical wall portion covers the entire outer circumference of the wound electrode body and is integrally molded with the crimped portion. The lid closes the opening of the case body. The cover includes a first external terminal and a second external terminal. The first external terminal is positioned such that it coincides with the radial center of the wound electrode body when viewed from the axial direction. The second external terminal is fixed to the case body, The case body further includes an electrically insulating sealing layer disposed between the second external terminal and the crimped portion, The first current collector is positioned on one side of the wound electrode body in the axial direction and is connected to the first external terminal. The second current collector is positioned on one side of the wound electrode body in the axial direction and between the seal layer and the second external terminal, and is joined to the second external terminal by being fixed together with the seal layer and the second external terminal to the crimping portion. A storage cell in which the crimped portion and the cylindrical wall portion are electrically insulated from the second external terminal.

2. The first external terminal includes a disk portion and a rivet portion, The disk portion is exposed to the outside and is located opposite to the wound electrode body when viewed from the second external terminal. The rivet portion is connected to the disk portion and extends from the center of the disk portion when viewed from the axial direction toward the wound electrode body. The second external terminal is provided with a through hole through which the rivet portion is inserted. The first current collector is joined to the rivet portion by welding. The energy storage cell according to claim 1, wherein the cover further includes an insulating member disposed between the disc portion and the rivet portion and the second external terminal.

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