Power storage cell

Abstract

To improve the reliability of a power storage cell furthermore.SOLUTION: In a power storage cell 1, a first wound electrode assembly 10 includes a first positive electrode 11P and a first negative electrode 11N. A second wound electrode assembly 20 includes a second positive electrode 21P and a second negative electrode 21N. The second positive electrode 21P is not in contact with the first positive electrode 11P. The second negative electrode 21N is not in contact with the first negative electrode 11N. The second wound electrode assembly 20 is formed by being wound around the first wound electrode assembly 10 on the outer peripheral side of the first wound electrode assembly 10. A positive electrode current collector member 40 is electrically connected to both the first positive electrode 11P and the second positive electrode 21P. A negative electrode current collector member 50 is electrically connected to both the first negative electrode 11N and the second negative electrode 21N.SELECTED DRAWING: Figure 1

Description

[Technical field]

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

[0002] Patent Document 1 (JP Patent Publication No. 11-273743) discloses a conventional cylindrical nonaqueous electrolyte secondary battery in which a spirally wound electrode body is housed together with a nonaqueous electrolyte in a cylindrical battery can. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 11-273743 Summary of the Invention [Problem to be solved by the invention]

[0004] For example, in a storage cell such as the secondary battery disclosed in Patent Document 1, pressure may be applied to the case from the outer periphery of the case. In this case, the case deforms and further presses the electrode assembly inside. This may cause the electrode assembly to break, and the storage cell may lose its original function. There is room for further improvement in the reliability of the storage cell.

[0005] The present disclosure has been made in consideration of the above-mentioned problems, and has an object to provide a power storage cell with improved reliability. [Means for solving the problem]

[0006] The energy storage cell according to the present disclosure includes a first wound electrode body, a second wound electrode body, a case, a positive electrode current collector, and a negative electrode current collector. The first wound electrode body includes a first positive electrode and a first negative electrode. The second wound electrode body includes a second positive electrode and a second negative electrode. The second positive electrode is not in contact with the first positive electrode. The second negative electrode is not in contact with the first negative electrode. The second wound electrode body is formed by being wound around the first wound electrode body on the outer periphery side of the first wound electrode body. The case houses the first wound electrode body and the second wound electrode body. The positive electrode current collector is housed in the case. The positive electrode current collector is disposed on one side of the first wound electrode body and the second wound electrode body in the axial direction of the first wound electrode body. The positive electrode current collecting member is electrically connected to both the first positive electrode and the second positive electrode. The negative electrode current collecting member is housed in a case. The negative electrode current collecting member is disposed on the other side of the first wound electrode body and the second wound electrode body in the axial direction. The negative electrode current collecting member is electrically connected to both the first negative electrode and the second negative electrode.

[0007] According to the above configuration, even if pressure is applied to the case from the outer periphery side of the case and the second wound electrode body is broken, the first wound electrode body can function normally together with the positive and negative current collecting members, thereby further improving the reliability of the energy storage cell. Effect of the Invention

[0008] According to the present disclosure, it is possible to provide a storage cell with improved reliability. [Brief description of the drawings]

[0009] [Figure 1] FIG. 2 is a cross-sectional view showing a storage cell according to one embodiment. [Diagram 2] 3 is a partially exploded perspective view showing a first wound electrode body, a second wound electrode body, and a heat insulating member. FIG. [Diagram 3] FIG. 2 is an exploded perspective view showing an energy storage cell according to an embodiment. [Figure 4] FIG. 2 is another exploded perspective view showing the energy storage cell according to the embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Hereinafter, a storage cell according to an embodiment of the present disclosure will be described with reference to the drawings. The same or corresponding parts in the drawings are denoted by the same reference characters, and description thereof will not be repeated.

[0011] Fig. 1 is a cross-sectional view showing an electric storage cell according to one embodiment. As shown in Fig. 1, an electric storage cell 1 according to one embodiment of the present disclosure is a cylindrical battery. The electric storage cell 1 includes a first wound electrode body 10, a second wound electrode body 20, a case 30, a positive electrode current collecting member 40, a negative electrode current collecting member 50, and a heat insulating member 60.

[0012] First, the first wound electrode body 10 will be described. Fig. 2 is a perspective view showing a partially exploded view of the first wound electrode body, the second wound electrode body, and the heat insulating member. As shown in Figs. 1 and 2, the first wound electrode body 10 is wound to have a cylindrical shape. Fig. 2 shows the first wound electrode body 10 in a slightly unwound state.

[0013] The first wound electrode body 10 includes a first positive electrode 11P, a first negative electrode 11N, and a first separator 12. The first wound electrode body 10 is wound so that the first positive electrode 11P, the first negative electrode 11N, and the first separator 12 surround the periphery of the winding axis α.

[0014] The first positive electrode 11P and the first negative electrode 11N have a sheet-like outer shape. The first wound electrode body 10 is composed of an electrode plate group in which the first positive electrode 11P and the first negative electrode 11N are wound with a first separator 12 interposed therebetween.

[0015] The first separator 12 is provided between the first positive electrode 11P and the first negative electrode 11N. The first separator 12 separates the first positive electrode 11P from the first negative electrode 11N while allowing ions (e.g., lithium ions) to move between the first positive electrode 11P (positive electrode active material) and the first negative electrode 11N (negative electrode active material).

[0016] First positive electrode 11P includes first positive electrode current collector foil 111P and first positive electrode composite material layer 112P. First positive electrode current collector foil 111P is made of, for example, aluminum.

[0017] The first positive electrode mixture layer 112P is applied to both radial surfaces of the first positive electrode current collector foil 111P (first positive electrode coated portion 111PA described later). The first positive electrode mixture layer 112P is in close contact with the first separator 12. The first positive electrode mixture layer 112P is formed by applying a positive electrode slurry to the surface of the first positive electrode current collector foil 111P and drying it. The positive electrode slurry is a slurry prepared by kneading the materials of the first positive electrode mixture layer 112P (such as a positive electrode active material and a binder) and a solvent. The thickness of the first positive electrode mixture layer 112P is, for example, 0.1 μm or more and 1000 μm or less.

[0018] The first positive current collector foil 111P includes a first positive coated portion 111PA and a first positive uncoated portion 111PB. The first positive coated portion 111PA is a portion of the first positive current collector foil 111P that is coated with the first positive composite material layer 112P. In other words, the first positive coated portion 111PA is a portion that is not exposed because it is covered with the first positive composite material layer 112P.

[0019] The first positive electrode uncoated portion 111PB is an exposed portion of the first positive electrode current collector foil 111P that is not covered by the first positive electrode composite layer 112P. The first positive electrode uncoated portion 111PB is located on the first direction Z1 side along the axial direction Z relative to the first positive electrode coated portion 111PA. Specifically, the first positive electrode uncoated portion 111PB protrudes in the first direction Z1 from the first positive electrode coated portion 111PA. The first positive electrode uncoated portion 111PB is bent radially inward.

[0020] The first positive electrode uncoated portion 111PB includes a plurality of extending portions 111PC. The extending portions 111PC are arranged along the winding direction of the first wound electrode body 10.

[0021] First negative electrode 11N includes first negative electrode current collector foil 111N and first negative electrode composite material layer 112N. First negative electrode current collector foil 111N is made of, for example, copper.

[0022] The first negative electrode mixture layer 112N is applied to both radial surfaces of the first negative electrode current collector foil 111N (first negative electrode coated portion 111NA described later). The first negative electrode mixture layer 112N is in close contact with the first separator 12. The first negative electrode mixture layer 112N is formed by applying a negative electrode slurry to the surface of the first negative electrode current collector foil 111N and drying it. The negative electrode slurry is a slurry prepared by kneading the materials of the first negative electrode mixture layer 112N (negative electrode active material, binder, etc.) and a solvent. The thickness of the first negative electrode mixture layer 112N is, for example, 0.1 μm or more and 1000 μm or less.

[0023] The first negative electrode current collector foil 111N includes a first negative electrode coated portion 111NA and a first negative electrode uncoated portion 111NB. The first negative electrode coated portion 111NA is a portion of the first negative electrode current collector foil 111N that is coated with the first negative electrode composite material layer 112N. In other words, the first negative electrode coated portion 111NA is a portion that is not exposed because it is covered with the first negative electrode composite material layer 112N.

[0024] The first negative electrode uncoated portion 111NB is an exposed portion of the first negative electrode current collector foil 111N that is not covered by the first negative electrode composite layer 112N. The first negative electrode uncoated portion 111NB is located closer to the second direction Z2 along the axial direction than the first negative electrode coated portion 111NA. The second direction Z2 is the opposite direction to the first direction Z1. The first negative electrode uncoated portion 111NB protrudes from the first negative electrode coated portion 111NA in the second direction Z2 along the axial direction Z. The first negative electrode uncoated portion 111NB is bent radially inward.

[0025] The first negative electrode uncoated portion 111NB includes a plurality of extending portions 111NC. The extending portions 111NC are arranged along the winding direction of the first wound electrode body 10.

[0026] Next, the second wound electrode body 20 will be described. As shown in Fig. 1 and Fig. 2, the second wound electrode body 20 is formed by winding around the first wound electrode body 10 on the outer periphery side of the first wound electrode body 10. The second wound electrode body 20 is wound to have a cylindrical shape. Fig. 2 shows the second wound electrode body 20 in a slightly unwound state.

[0027] The second wound electrode body 20 includes a second positive electrode 21P, a second negative electrode 21N, and a second separator 22. In the second wound electrode body 20, the second positive electrode 21P, the second negative electrode 21N, and the second separator 22 are wound so as to surround the winding axis α, similar to the first wound electrode body 10.

[0028] The second positive electrode 21P is not in contact with the first positive electrode 11P. The second positive electrode 21P is formed of a member that is discontinuous with the first positive electrode 11P. The second negative electrode 21N is not in contact with the first negative electrode 11N. The second negative electrode 21N is formed of a member that is discontinuous with the first negative electrode 11N. In this embodiment, the second separator 22 is formed of a member that is discontinuous with the first separator 12. However, the second separator 22 may be formed of an integral member together with the first separator 12.

[0029] Except for the configuration described above, the second wound electrode body 20 can have a configuration similar to that of the first wound electrode body 10. Except for the configuration described above, the second positive electrode 21P, the second negative electrode 21N, and the second separator 22 for the second wound electrode body 20 have configurations similar to those of the first positive electrode 11P, the first negative electrode 11N, and the first separator 12 for the first wound electrode body 10, respectively.

[0030] The second positive electrode 21P includes a second positive electrode current collector foil 211P and a second positive electrode composite layer 212P. The second positive electrode current collector foil 211P and the second positive electrode composite layer 212P for the second positive electrode 21P have the same configuration as the first positive electrode current collector foil 111P and the first positive electrode composite layer 112P for the first positive electrode 11P, respectively. The second positive electrode current collector foil 211P includes a second positive electrode coated portion 211PA and a second positive electrode uncoated portion 211PB. The second positive electrode coated portion 211PA and the second positive electrode uncoated portion 211PB for the second positive electrode current collector foil 211P have the same configuration as the first positive electrode coated portion 111PA and the first positive electrode uncoated portion 111PB for the first positive electrode current collector foil 111P, respectively. The second positive electrode uncoated portion 211PB includes a plurality of extending portions 211PC, similar to the first positive electrode uncoated portion 111PB.

[0031] The second negative electrode 21N includes a second negative electrode current collector foil 211N and a second negative electrode composite layer 212N. The second negative electrode current collector foil 211N and the second negative electrode composite layer 212N for the second negative electrode 21N have the same configuration as the first negative electrode current collector foil 111N and the first negative electrode composite layer 112N for the first negative electrode 11N, respectively. The second negative electrode current collector foil 211N includes a second negative electrode coated portion 211NA and a second negative electrode uncoated portion 211NB. The second negative electrode coated portion 211NA and the second negative electrode uncoated portion 211NB for the second negative electrode current collector foil 211N have the same configuration as the first negative electrode coated portion 111NA and the first negative electrode uncoated portion 111NB for the first negative electrode current collector foil 111N, respectively. The second negative electrode uncoated portion 211NB includes a plurality of extending portions 211NC, similar to the plurality of extending portions 111NC for the first negative electrode uncoated portion 111NB.

[0032] Next, the case 30 will be described. Fig. 3 is an exploded perspective view showing an energy storage cell according to one embodiment. Fig. 4 is another exploded perspective view showing an energy storage cell according to one embodiment. As shown in Figs. 1, 3, and 4, the case 30 accommodates the first wound electrode body 10 and the second wound electrode body 20.

[0033] The case 30 includes a positive electrode terminal 31P, a negative electrode terminal 31N, a cylindrical wall portion 32, a sealing plate 33, a sealing plug 34, an outer gasket 35, an inner gasket 36, and an annular gasket 37.

[0034] The positive electrode terminal 31P is exposed to the outside of the case 30. The positive electrode terminal 31P is disposed on the first direction Z1 side of the first wound electrode body 10. The positive electrode terminal 31P includes a disk portion 311 and a rivet portion 312. The disk portion 311 is exposed to the outside. The rivet portion 312 is connected to the disk portion 311. The rivet portion 312 extends from the center of the disk portion 311 when viewed from the axial direction Z. The rivet portion 312 is located approximately on the winding axis α of the first wound electrode body 10. The rivet portion 312 extends to the second direction Z2 side. The positive electrode terminal 31P is formed of aluminum, for example.

[0035] The negative electrode terminal 31N is provided so as to be perpendicular to the axial direction Z. A through hole 31Nh is provided in the negative electrode terminal 31N. Therefore, the negative electrode terminal 31N has an annular outer shape when viewed from the axial direction Z. The negative electrode terminal 31N is located between the disk portion 311 and the first wound electrode body 10 and the second wound electrode body 20 in the axial direction Z. The rivet portion 312 is inserted through the through hole 31Nh. The rivet portion 312 extends to the inside of the case 30. The material constituting the negative electrode terminal 31N is not particularly limited, but is formed from aluminum, copper, stainless steel, or the like.

[0036] The cylindrical wall portion 32 is provided on the outer circumferential side of the second wound electrode body 20. The cylindrical wall portion 32 covers the entire outer circumferential side of the second wound electrode body 20. The cylindrical wall portion 32 has a cylindrical shape. An end portion of the cylindrical wall portion 32 on the first direction Z1 side is connected to the negative electrode terminal 31N. The cylindrical wall portion 32 is formed integrally with the negative electrode terminal 31N. The material constituting the cylindrical wall portion 32 is not particularly limited, but is formed of aluminum, copper, stainless steel, or the like.

[0037] A crimped portion 32d is formed at the end portion on the second direction Z2 side of the cylindrical wall portion 32. The crimped portion 32d is formed in an annular shape along the circumferential direction of the second wound electrode body 20. Note that Fig. 4 shows the cylindrical wall portion 32 in a state before the crimped portion 32d is formed.

[0038] The sealing plate 33 is connected to an end of the cylindrical wall portion 32 on the second direction Z2 side. The sealing plate 33 seals the opening of the cylindrical wall portion 32 on the second direction Z2 side. The crimping portion 32d is crimped to the outer periphery of the sealing plate 33. The sealing plate 33 may be connected to the cylindrical wall portion 32 by welding such as laser welding. The material constituting the sealing plate 33 is not particularly limited, but it is formed of aluminum, copper, stainless steel, or the like.

[0039] A through hole 33h is formed in the sealing plate 33. The through hole 33h may be used to inject an electrolyte (not shown) to be contained in the case 30. The through hole 33h is formed in the center of the sealing plate 33 when viewed from the axial direction Z.

[0040] The sealing plug 34 is inserted into the through hole 33h of the sealing plate 33. This fixes the sealing plug 34 to the sealing plate 33. The sealing plug 34 and the through hole 33h can function as a pressure relief valve for releasing the pressure inside the case 30 when the pressure inside the case 30 becomes excessively high.

[0041] The external gasket 35 is disposed between the positive electrode terminal 31P and the negative electrode terminal 31N. The external gasket 35 is formed of an insulating material. Therefore, the external gasket 35 insulates the positive electrode terminal 31P from the negative electrode terminal 31N. The external gasket 35 covers the surface of the disk portion 311 on the second direction Z2 side. The rivet portion 312 penetrates the external gasket 35 in the axial direction Z. The external gasket 35 covers the inner surface in the radial direction of the through hole 31Nh of the negative electrode terminal 31N.

[0042] The internal gasket 36 covers the surface of the negative electrode terminal 31N on the second direction Z2 side. The internal gasket 36 is made of an insulating material. Therefore, the internal gasket 36 insulates the first wound electrode body 10 and the second wound electrode body 20 from the negative electrode terminal 31N. The rivet portion 312 further penetrates the internal gasket 36 in the axial direction Z. Therefore, the rivet portion 312 is exposed to the inside of the case 30.

[0043] The annular gasket 37 has a circular outer shape. The annular gasket 37 covers the outer peripheral edge of the sealing plate 33. The annular gasket 37 is disposed between the outer peripheral edge of the sealing plate 33 and the crimped portion 32d of the cylindrical wall portion 32. The annular gasket 37 may be made of an insulating material or a conductive material. The case 30 may not include the annular gasket 37.

[0044] In this embodiment, the sealing plate 33 is insulated from the cylindrical wall portion 32 by the annular gasket 37, but the sealing plate 33 may be electrically connected to the cylindrical wall portion 32. In this case, the sealing plate 33 may be the negative electrode terminal.

[0045] In addition, in this embodiment, the portion of the case 30 facing the first direction Z1 side is composed of the positive electrode terminal 31P, the negative electrode terminal 31N, and the external gasket 35. However, as a part of the above-mentioned portion, the case 30 may further have a top plate portion. The top plate portion may be located, for example, further inwardly of the negative electrode terminal 31N. The top plate portion may be arranged so as to be aligned with the positive electrode terminal 31P in the axial direction Z. The top plate portion may be insulated from the negative electrode terminal 31N. In addition, when the sealing plate 33 serves as the negative electrode terminal as described above, a top plate portion electrically insulated from the sealing plate 33 and the cylindrical wall portion 32 may be arranged instead of the negative electrode terminal 31N.

[0046] Next, the positive current collecting member 40 will be described. As shown in Figures 1 and 3, the positive current collecting member 40 is housed in a case 30. The positive current collecting member 40 is disposed on the first direction Z1 side of the first wound electrode body 10 and the second wound electrode body 20 in the axial direction Z of the first wound electrode body 10.

[0047] An internal gasket 36 is disposed between the positive current collecting member 40 and the negative terminal 31N. This electrically insulates the positive current collecting member 40 and the negative terminal 31N from each other. The internal gasket 36 also extends to the outer circumferential side of the positive current collecting member 40. This also places the internal gasket 36 between the positive current collecting member 40 and the cylindrical wall portion 32. This electrically insulates the positive current collecting member 40 and the cylindrical wall portion 32 from each other.

[0048] The positive current collecting member 40 has a plate-like outer shape. The positive current collecting member 40 has a substantially circular outer shape. The positive current collecting member 40 includes a plurality of first positive electrode connection portions 41, a plurality of second positive electrode connection portions 42, a terminal connection portion 43, a plurality of first fuse portions 44, a plurality of second fuse portions 45, an outer peripheral edge portion 46, and a plurality of positive electrode spoke portions 47.

[0049] Each of the multiple first positive electrode connecting parts 41 is connected to the first positive electrode 11P. Specifically, each of the multiple first positive electrode connecting parts 41 is joined to the first positive electrode uncoated part 111PB of the first positive electrode 11P by welding. The multiple first positive electrode connecting parts 41 are spaced apart from each other. The multiple first positive electrode connecting parts 41 are arranged at equal intervals in the circumferential direction around the terminal connecting part 43.

[0050] Each of the multiple second positive electrode connecting parts 42 is connected to the second positive electrode 21P. Specifically, each of the multiple second positive electrode connecting parts 42 is joined to the second positive electrode uncoated part 211PB of the second positive electrode 21P by welding. The multiple second positive electrode connecting parts 42 are spaced apart from each other. The multiple second positive electrode connecting parts 42 are arranged at equal intervals in the circumferential direction centered on the terminal connecting part 43. The multiple first positive electrode connecting parts 41 and the multiple second positive electrode connecting parts 42 are arranged alternately in the circumferential direction.

[0051] The terminal connection portion 43 is connected to the positive electrode terminal 31P. Specifically, the terminal connection portion 43 is joined to the rivet portion 312 of the positive electrode terminal 31P by welding. As a result, in this embodiment, the positive electrode terminal 31P is electrically connected to the positive electrode current collecting member 40. The terminal connection portion 43 is positioned so as to overlap with the rivet portion 312 of the positive electrode terminal 31P when viewed from the axial direction Z. The terminal connection portion 43 is electrically connected to the first positive electrode connection portion 41 and the second positive electrode connection portion 42. However, in this embodiment, the terminal connection portion 43 is disposed so as to be spaced apart from the first positive electrode connection portion 41 and the second positive electrode connection portion 42.

[0052] The multiple first fuse portions 44 are connected to the multiple first positive electrode connection portions 41, respectively. Each first fuse portion 44 is located opposite the terminal connection portion 43 when viewed from the corresponding first positive electrode connection portion 41. The dimension of the first fuse portion 44 in the circumferential direction is smaller than the dimension of the edge of the first positive electrode connection portion 41 facing the outer circumferential side in the circumferential direction. The thickness of the first fuse portion 44 is preferably smaller than the thickness of the first positive electrode connection portion 41.

[0053] The second fuse portions 45 are connected to the second positive electrode connecting portions 42, respectively. Each second fuse portion 45 is located opposite the terminal connecting portion 43 as viewed from the corresponding second positive electrode connecting portion 42. The dimension of the second fuse portion 45 in the circumferential direction is smaller than the dimension of the edge of the second positive electrode connecting portion 42 facing the outer circumferential side in the circumferential direction. The thickness of the second fuse portion 45 is preferably smaller than the thickness of the second positive electrode connecting portion 42.

[0054] The outer peripheral edge portion 46 is provided on the outer peripheral edge of the positive electrode current collecting member 40. The outer peripheral edge portion 46 is provided on the outer peripheral side of the plurality of first positive electrode connecting portions 41 and the plurality of second positive electrode connecting portions 42. The outer peripheral edge portion 46 is separated from the plurality of first positive electrode connecting portions 41 and the plurality of second positive electrode connecting portions 42. The outer peripheral edge portion 46 is connected to the plurality of first fuse portions 44 and the plurality of second fuse portions 45. The outer peripheral edge portion 46 extends in an annular shape with the terminal connecting portion 43 as the center.

[0055] The positive electrode spoke portions 47 are spaced apart from one another. Each of the positive electrode spoke portions 47 connects the terminal connection portion 43 and the outer circumferential edge portion 46. Each of the positive electrode spoke portions 47 extends in a radial direction centered on the terminal connection portion 43. Each of the positive electrode spoke portions 47 is disposed between a first positive electrode connection portion 41 and a second positive electrode connection portion 42 that are adjacent to each other in the circumferential direction.

[0056] Therefore, the conductive path PP1 from the first positive electrode connection portion 41 to the terminal connection portion 43 in the positive electrode current collecting member 40 passes through the first fuse portion 44, the outer circumferential edge portion 46, and the positive electrode spoke portion 47 (see FIG. 3). The first fuse portion 44 is disposed in the conductive path PP1 from the first positive electrode connection portion 41 to the terminal connection portion 43 in the positive electrode current collecting member 40.

[0057] Furthermore, the conductive path PP2 from the second positive electrode connection portion 42 to the terminal connection portion 43 in the positive electrode current collecting member 40 passes through the second fuse portion 45, the outer circumferential edge portion 46, and the positive electrode spoke portion 47 (see FIG. 3). The second fuse portion 45 is disposed in the conductive path PP2 from the second positive electrode connection portion 42 to the terminal connection portion 43 in the positive electrode current collecting member 40.

[0058] The first fuse portion 44 is provided so as not to be located on the conductive path PP2 from the second positive electrode connection portion 42 to the terminal connection portion 43 in the positive electrode current collecting member 40. The second fuse portion 45 is provided so as not to be located on the conductive path PP1 from the first positive electrode connection portion 41 to the terminal connection portion 43 in the positive electrode current collecting member 40.

[0059] In this embodiment, the positive current collecting member 40 has the above-mentioned configuration and is therefore electrically connected to both the first positive electrode 11P and the second positive electrode 21P. As a result, the positive current collecting member 40 is positively charged. The positive current collecting member 40 is also electrically connected to the positive terminal 31P. As a result, the positive terminal 31P is positively charged.

[0060] The positive current collecting member 40 is not limited to a plate-shaped member as described above. The positive current collecting member 40 may be composed of a plurality of tab leads. One tab lead may electrically connect the first positive electrode 11P and the positive electrode terminal 31P, and another tab lead may electrically connect the second positive electrode 21P and the positive electrode terminal 31P. Furthermore, a first fuse portion 44 may be provided in one tab lead, and a second fuse portion 45 may be provided in the other tab lead.

[0061] Next, the negative current collecting member 50 will be described. As shown in Fig. 1 and Fig. 4, the negative current collecting member 50 is housed in the case 30. The negative current collecting member 50 is disposed on the second direction Z2 side of the first wound electrode body 10 and the second wound electrode body 20 in the axial direction Z. The negative current collecting member 50 is electrically connected to both the first negative electrode 11N and the second negative electrode 21N. The configuration of the negative current collecting member 50 is not particularly limited.

[0062] The negative electrode current collecting member 50 in this embodiment is joined to the cylindrical wall portion 32 by being crimped together with the outer circumferential edge of the sealing plate 33 and the annular gasket 37 at the crimping portion 32d.

[0063] The negative electrode current collecting member 50 has a plate-like outer shape. The negative electrode current collecting member 50 has a substantially circular outer shape. The negative electrode current collecting member 50 includes a plurality of first negative electrode connecting portions 51, a plurality of second negative electrode connecting portions 52, a case connecting portion 53, a central portion 54, and a plurality of negative electrode spoke portions 55.

[0064] Each of the multiple first negative electrode connecting portions 51 is connected to the first negative electrode 11N. Specifically, each of the multiple first negative electrode connecting portions 51 is joined to the first negative electrode uncoated portion 111NB of the first negative electrode 11N by welding. The multiple first negative electrode connecting portions 51 are spaced apart from each other. The multiple first negative electrode connecting portions 51 are arranged at equal intervals in the circumferential direction around the central portion 54.

[0065] Each of the multiple second negative electrode connecting parts 52 is connected to the second negative electrode 21N. Specifically, each of the multiple second negative electrode connecting parts 52 is joined to the second negative electrode uncoated part 211NB of the second negative electrode 21N by welding. The multiple second negative electrode connecting parts 52 are spaced apart from each other. The multiple second negative electrode connecting parts 52 are arranged at equal intervals in the circumferential direction centered on the central part 54. The multiple first negative electrode connecting parts 51 and the multiple second negative electrode connecting parts 52 are arranged alternately in the circumferential direction.

[0066] The case connection portion 53 is connected to the cylindrical wall portion 32. Specifically, the case connection portion 53 is joined to the cylindrical wall portion 32 by crimping the outer periphery of the sealing plate 33 and the annular gasket together at the crimping portion 32d. As a result, in this embodiment, the negative electrode terminal 31N is electrically connected to the negative electrode current collecting member 50 via the cylindrical wall portion 32. The case connection portion 53 is provided on the outer periphery of the negative electrode current collecting member 50. The case connection portion 53 is provided on the further outer periphery side of the multiple first negative electrode connection portions 51 and the multiple second negative electrode connection portions 52. The case connection portion 53 is separated from the multiple first negative electrode connection portions 51 and the multiple second negative electrode connection portions 52. The case connection portion 53 extends in an annular shape with the central portion 54 as the center.

[0067] The central portion 54 is positioned so as to overlap the first wound electrode body 10 in the axial direction Z. The central portion 54 is provided on the inner circumferential side of the multiple first negative electrode connecting portions 51 and the multiple second negative electrode connecting portions 52. The central portion 54 is connected to the multiple first negative electrode connecting portions 51 and the multiple second negative electrode connecting portions 52.

[0068] The negative electrode spoke portions 55 are spaced apart from one another. Each of the negative electrode spoke portions 55 connects the central portion 54 and the case connection portion 53. Each of the negative electrode spoke portions 55 extends in a radial direction centered on the central portion 54. Each of the negative electrode spoke portions 55 is disposed between the first negative electrode connection portion 51 and the second negative electrode connection portion 52 that are adjacent to each other in the circumferential direction.

[0069] Therefore, in the negative electrode collecting member 50, the conductive path PN1 from the first negative electrode connection portion 51 to the case connection portion 53, and the conductive path PN2 from the second negative electrode connection portion 52 to the case connection portion 53 both pass through the central portion 54 and the negative electrode spoke portion 55.

[0070] The negative electrode current collecting member 50 is not limited to the plate-shaped member as described above. The negative electrode current collecting member 50 may be composed of a plurality of tab leads. One tab lead may electrically connect the first negative electrode 11N and the negative electrode terminal 31N, and another tab lead may electrically connect the second negative electrode 21N and the negative electrode terminal 31N. In addition, when the sealing plate 33 serves as the negative electrode terminal or when the sealing plate 33 is electrically connected to the negative electrode terminal 31N, the first negative electrode 11N and the second negative electrode 21N may be directly joined to the sealing plate 33 by welding or the like.

[0071] Finally, the heat insulating member 60 will be described. As shown in Figs. 1 to 4, the heat insulating member 60 has a cylindrical outer shape. The heat insulating member 60 is disposed between the second wound electrode body 20 and the second wound electrode body 20 in the radial direction of the first wound electrode body 10. The heat insulating member 60 is preferably formed from a material having electrical insulation properties. For example, a resin composition such as a foamed resin can be used for the heat insulating member 60.

[0072] As described above, the energy storage cell 1 according to an embodiment of the present disclosure includes a first wound electrode body 10, a second wound electrode body 20, a case 30, a positive electrode current collector 40, and a negative electrode current collector 50. The first wound electrode body 10 includes a first positive electrode 11P and a first negative electrode 11N. The second wound electrode body 20 includes a second positive electrode 21P and a second negative electrode 21N. The second positive electrode 21P is not in contact with the first positive electrode 11P. The second negative electrode 21N is not in contact with the first negative electrode 11N. The second wound electrode body 20 is formed by being wound around the first wound electrode body 10 on the outer periphery side of the first wound electrode body 10. The case 30 accommodates the first wound electrode body 10 and the second wound electrode body 20. The positive electrode current collecting member 40 is housed in the case 30. The positive electrode current collecting member 40 is disposed on one side of the first wound electrode body 10 and the second wound electrode body 20 in the axial direction Z of the first wound electrode body 10. The positive electrode current collecting member 40 is electrically connected to both the first positive electrode 11P and the second positive electrode 21P. The negative electrode current collecting member 50 is housed in the case 30. The negative electrode current collecting member 50 is disposed on the other side of the first wound electrode body 10 and the second wound electrode body 20 in the axial direction Z. The negative electrode current collecting member 50 is electrically connected to both the first negative electrode 11N and the second negative electrode 21N.

[0073] According to the above configuration, even if pressure is applied to the case 30 from the outer periphery side of the case 30 and the second wound electrode body 20 breaks, the first wound electrode body 10 can function normally together with the positive electrode current collecting member 40 and the negative electrode current collecting member 50. This further improves the reliability of the energy storage cell 1.

[0074] In this embodiment, the case 30 includes a positive electrode terminal 31P. The positive electrode terminal 31P is exposed to the outside of the case 30. The positive electrode terminal 31P is electrically connected to the positive electrode current collecting member 40. The positive electrode current collecting member 40 includes a first positive electrode connection portion 41, a second positive electrode connection portion 42, a terminal connection portion 43, and a first fuse portion 44. The first positive electrode connection portion 41 is connected to the first positive electrode 11P. The second positive electrode connection portion 42 is connected to the second positive electrode 21P. The terminal connection portion 43 is connected to the positive electrode terminal 31P. The first fuse portion 44 is disposed in a conductive path PP1 from the first positive electrode connection portion 41 to the terminal connection portion 43 in the positive electrode current collecting member 40.

[0075] The first wound electrode body 10 is located on the inner circumferential side of the second wound electrode body 20, and therefore heat is relatively difficult to dissipate. However, according to the above configuration, when the first wound electrode body 10 generates excessive heat, the first fuse portion 44 is cut. A short circuit in the first wound electrode body 10 is suppressed. This further improves the safety of the energy storage cell 1.

[0076] In this embodiment, the positive current collecting member 40 includes a second fuse portion 45. The second fuse portion 45 is disposed in the conductive path PP2 from the second positive electrode connecting portion 42 to the terminal connecting portion 43 in the positive current collecting member 40.

[0077] According to the above configuration, when the second wound electrode body 20 collapses and an excessive current flows through the second wound electrode body 20, the second fuse portion 45 is cut off. A short circuit in the second wound electrode body 20 is suppressed. This further improves the safety of the energy storage cell 1.

[0078] In this embodiment, the first fuse portion 44 is provided so as not to be located on the conductive path PP2 from the second positive electrode connection portion 42 to the terminal connection portion 43 in the positive electrode current collecting member 40. The second fuse portion 45 is provided so as not to be located on the conductive path PP1 from the first positive electrode connection portion 41 to the terminal connection portion 43 in the positive electrode current collecting member 40.

[0079] According to the above configuration, a short circuit is individually suppressed in the first wound electrode body 10 and in the second wound electrode body 20. This further improves both the reliability and safety of the energy storage cell 1.

[0080] Moreover, in this embodiment, the energy storage cell 1 further includes a cylindrical heat insulating member 60. The heat insulating member 60 is disposed between the second wound electrode body 20 and the second wound electrode body 20 in the radial direction of the first wound electrode body 10.

[0081] According to the above configuration, when the first wound electrode body 10 generates excessive heat, the heat generated from the first wound electrode body 10 can be prevented from being transmitted to the second wound electrode body 20. The first fuse portion 44 is cut. A short circuit in the first wound electrode body 10 is prevented. This allows the second wound electrode body 20 to function normally together with the positive electrode current collecting member 40 and the negative electrode current collecting member 50. This further improves the reliability of the energy storage cell 1.

[0082] The embodiments disclosed herein should be considered to be illustrative and not restrictive in all respects. The scope of the present disclosure is defined by the claims, not by the description of the above-mentioned embodiments, and is intended to include all modifications within the meaning and scope of the claims. [Explanation of symbols]

[0083] 1 storage cell, 10 first wound electrode body, 11N first negative electrode, 111N first negative electrode current collector foil, 111NA first negative electrode coated portion, 111NB first negative electrode uncoated portion, 112N first negative electrode composite layer, 11P first positive electrode, 111P first positive electrode current collector foil, 111PA first positive electrode coated portion, 111PB first positive electrode uncoated portion, 112P first positive electrode composite layer, 12 first separator, 20 second wound electrode body, 21N second negative electrode, 211N second negative electrode current collector foil, 211NA second negative electrode coated portion, 211NB second negative electrode uncoated portion, 212N second negative electrode composite layer, 21P second positive electrode, 211P second positive electrode current collector foil, 211PA second positive electrode coated portion, 211PB second positive electrode uncoated portion, 212P second positive electrode composite layer, 22 second separator, 30 case, 31N negative electrode terminal, 31P positive electrode terminal, 311 disk portion, 312 rivet portion, 32 cylindrical wall portion, 32d crimping portion, 33 sealing plate, 34 sealing plug, 35 external gasket, 36 internal gasket, 37 annular gasket, 40 positive electrode current collecting member, 41 first positive electrode connection portion, 42 second positive electrode connection portion, 43 terminal connection portion, 44 first fuse portion, 45 second fuse portion, 46 outer periphery, 47 positive electrode spoke portion, 50 negative electrode current collecting member, 51 first negative electrode connection portion, 52 second negative electrode connection portion, 53 case connection portion, 54 center portion, 55 negative electrode spoke portion, 60 heat insulating member.

Claims

1. a first wound electrode body including a first positive electrode and a first negative electrode; a second wound electrode body including a second positive electrode not in contact with the first positive electrode and a second negative electrode not in contact with the first negative electrode, the second wound electrode body being wound around the first wound electrode body on the outer periphery side of the first wound electrode body; a case that accommodates the first wound electrode body and the second wound electrode body; a positive electrode current collecting member that is housed in the case, that is disposed on one side of the first wound electrode body and the second wound electrode body in the axial direction of the first wound electrode body, and that is electrically connected to both the first positive electrode and the second positive electrode; a negative electrode current collecting member that is housed in the case, that is arranged on the other side of the first wound electrode body and the second wound electrode body in the axial direction, and that is electrically connected to both the first negative electrode and the second negative electrode.

2. the case includes a positive terminal exposed to an outside of the case and electrically connected to the positive current collecting member, The positive electrode current collecting member is A first positive electrode connector connected to the first positive electrode; A second positive electrode connector connected to the second positive electrode; A terminal connection portion connected to the positive electrode terminal; The energy storage cell according to claim 1 , further comprising: a first fuse portion disposed in a conductive path from the first positive electrode connection portion to the terminal connection portion in the positive electrode current collecting member.

3. the case includes a positive terminal exposed to an outside of the case and electrically connected to the positive current collecting member, The positive electrode current collecting member is A first positive electrode connector connected to the first positive electrode; A second positive electrode connector connected to the second positive electrode; A terminal connection portion connected to the positive electrode terminal; The energy storage cell according to claim 1 , further comprising: a second fuse portion disposed in a conductive path from the second positive electrode connection portion to the terminal connection portion in the positive electrode current collecting member.

4. a second fuse portion disposed in a conductive path from the second positive electrode connection portion to the terminal connection portion in the positive electrode current collecting member, the first fuse portion is provided so as not to be located on a conductive path from the second positive electrode connection portion to the terminal connection portion of the positive electrode current collecting member, The energy storage cell according to claim 2 , wherein the second fuse portion is provided so as not to be located on a conductive path from the first positive electrode connection portion to the terminal connection portion of the positive electrode current collecting member.

5. 5 . The energy storage cell according to claim 1 , further comprising a cylindrical heat insulating member arranged between the second wound electrode body and the second wound electrode body in a radial direction of the first wound electrode body.

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