Energy 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 a storage battery cell.

Background Art

[0002] Patent Document 1 (Japanese Patent Laid-Open No. 11-273743) discloses a conventional cylindrical non-aqueous electrolyte secondary battery. In the cylindrical non-aqueous electrolyte secondary battery, a spiral electrode body is housed together with a non-aqueous electrolyte in a cylindrical battery can.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] For example, in a storage battery cell such as the secondary battery disclosed in Patent Document 1, pressure may be applied to the case from the outer peripheral side of the case. In this case, when the case is deformed, the case further presses the internal electrode body. As a result, the electrode body may be crushed, and the storage battery cell may lose its original function. There is still room for further improvement in the reliability of 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 with improved reliability.

Means for Solving the Problems

[0006] A storage cell according to this disclosure comprises 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 winding around the first wound electrode body on its outer circumference. 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 positioned 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 collector is electrically connected to both the first and second positive electrodes. The negative electrode current collector is housed in a case. The negative electrode current collector is positioned on the other side of the first and second wound electrode bodies in the axial direction. The negative electrode current collector is electrically connected to both the first and second negative electrodes.

[0007] With the above configuration, even if pressure is applied to the case from the outer periphery and the second wound electrode body breaks, the first wound electrode body can still function normally together with the positive electrode current collector and the negative electrode current collector. This further improves the reliability of the energy storage cell. [Effects of the Invention]

[0008] According to this disclosure, it is possible to provide energy storage cells with improved reliability. [Brief explanation of the drawing]

[0009] [Figure 1] This is a cross-sectional view showing a power storage cell according to one embodiment. [Figure 2] This is a perspective view showing the first wound electrode body, the second wound electrode body, and the heat insulating member in a partially disassembled state. [Figure 3] This is an exploded perspective view showing a storage cell according to one embodiment. [Figure 4] This is another exploded perspective view showing a storage cell according to one embodiment. [Modes for carrying out the invention]

[0010] Hereinafter, an energy storage cell according to one 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 numerals, and their descriptions will not be repeated.

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

[0012] First, the first wound electrode body 10 will be described. Figure 2 is a perspective view showing the first wound electrode body, the second wound electrode body, and the heat insulating member in a partially disassembled state. As shown in Figures 1 and 2, the first wound electrode body 10 is wound into a cylindrical shape. In Figure 2, the state in which the winding of the first wound electrode body 10 has slightly unraveled is illustrated.

[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 such that the first positive electrode 11P, the first negative electrode 11N, and the first separator 12 surround 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 a group of electrode plates in which the first positive electrode 11P and the first negative electrode 11N are wound around a first separator 12.

[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 (positive electrode active material) and the first negative electrode 11N (negative electrode active material) while allowing ions (for example, lithium ions) to move between them.

[0016] The first positive electrode 11P includes a first positive electrode current collector foil 111P and a first positive electrode composite material layer 112P. The first positive electrode current collector foil 111P is formed of, for example, aluminum or the like.

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

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

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

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

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

[0022] The first negative electrode composite material layer 112N is coated on both radial surfaces of the first negative electrode current collector foil 111N (the first negative electrode coating portion 111NA described later). The first negative electrode composite material layer 112N is in close contact with the first separator 12. The first negative electrode composite material layer 112N is formed by coating a negative electrode slurry on 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 (negative electrode active material, binder, etc.) of the first negative electrode composite material layer 112N and a solvent. The thickness of the first negative electrode composite material 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 coating portion 111NA and a first non-coated portion 111NB of the negative electrode. The first negative electrode coating portion 111NA is the portion of the first negative electrode current collector foil 111N where the first negative electrode composite material layer 112N is coated. In other words, the first negative electrode coating portion 111NA is the portion that is not exposed because it is covered by the first negative electrode composite material layer 112N.

[0024] The first non-coated portion 111NB of the negative electrode is the portion of the first negative electrode current collector foil 111N that is not covered by the first negative electrode composite material layer 112N and is exposed. The first non-coated portion 111NB of the negative electrode is located on the Z2 side in the second direction along the axial direction, which is the opposite direction of the first direction Z1. The first non-coated portion 111NB of the negative electrode protrudes from the first negative electrode coating portion 111NA toward the Z2 side in the second direction along the axial direction Z. The first non-coated portion 111NB of the negative electrode is bent radially inward.

[0025] The first non-coated portion 111NB of the negative electrode includes a plurality of extending portions 111NC. The plurality of 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 Figures 1 and 2, the second wound electrode body 20 is formed by winding around the first wound electrode body 10 on its outer circumference. The second wound electrode body 20 is wound to form a cylindrical shape. Figure 2 shows the second wound electrode body 20 in a state where the winding has slightly unraveled.

[0027] The second wound electrode body 20 includes a second positive electrode 21P, a second negative electrode 21N, and a second separator 22. The second wound electrode body 20 is wound so that the second positive electrode 21P, the second negative electrode 21N, and the second separator 22 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 material that is discontinuous from 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 material that is discontinuous from the first negative electrode 11N. In this embodiment, the second separator 22 is formed of a material that is discontinuous from the first separator 12. However, the second separator 22 may be formed of a material that is integral with the first separator 12.

[0029] Except for the configuration described above, the second wound electrode body 20 may have the same configuration as 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 of the second wound electrode body 20 have the same configuration as the first positive electrode 11P, the first negative electrode 11N, and the first separator 12 of 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 relative to 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 relative to the first positive electrode 11P. 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 relative to 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 relative to the first positive electrode current collector foil 111P. The second uncoated positive electrode portion 211PB, like the first uncoated positive electrode portion 111PB, includes a plurality of extensions 211PC.

[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 have the same configuration as the first negative electrode current collector foil 111N and the first negative electrode composite layer 112N, respectively, for the second negative electrode 21N. 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 have the same configuration as the first negative electrode coated portion 111NA and the first negative electrode uncoated portion 111NB, respectively, for the first negative electrode current collector foil 111N. The second uncoated negative electrode portion 211NB includes multiple extensions 211NC, similar to the multiple extensions 111NC to the first uncoated negative electrode portion 111NB.

[0032] Next, we will describe case 30. Figure 3 is an exploded perspective view showing a storage cell according to one embodiment. Figure 4 is another exploded perspective view showing a storage cell according to one embodiment. As shown in Figures 1, 3, and 4, case 30 houses the first wound electrode body 10 and the second wound electrode body 20.

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

[0034] The positive terminal 31P is exposed to the outside of the case 30. The positive terminal 31P is located on the first direction Z1 side of the first wound electrode body 10. The positive 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 in the second direction Z2 side. The positive terminal 31P is formed of, for example, aluminum.

[0035] The negative electrode terminal 31N is positioned perpendicular to the axial direction Z. The negative electrode terminal 31N is provided with a through hole 31Nh. 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 in the axial direction Z between the disk portion 311 and the first wound electrode body 10 and the second wound electrode body 20. The rivet portion 312 is inserted through the through hole 31Nh. The rivet portion 312 extends into the interior of the case 30. The material constituting the negative electrode terminal 31N is not particularly limited, but it is formed from aluminum, copper, or stainless steel, etc.

[0036] The cylindrical wall portion 32 is provided on the outer circumference of the second wound electrode body 20. The cylindrical wall portion 32 covers the entire outer circumference of the second wound electrode body 20. The cylindrical wall portion 32 has a cylindrical shape. The end 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 integrally formed with the negative electrode terminal 31N. The material constituting the cylindrical wall portion 32 is not particularly limited, but it is formed from aluminum, copper, or stainless steel, etc.

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

[0038] The sealing plate 33 is connected to the 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 edge of the sealing plate 33. The sealing plate 33 may also 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 from aluminum, copper, or stainless steel, etc.

[0039] The sealing plate 33 has a through hole 33h formed therein. The through hole 33h may be used to inject an electrolyte (not shown) 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 through 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 to release the pressure inside the case 30 when the pressure inside the case 30 becomes excessively high.

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

[0042] The internal gasket 36 covers the second direction Z2 side surface of the negative electrode terminal 31N. 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 inside the case 30.

[0043] The annular gasket 37 has an annular outer shape. The annular gasket 37 covers the outer edge of the sealing plate 33. The annular gasket 37 is positioned between the outer 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. Note that the case 30 does not necessarily have to include the annular gasket 37.

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

[0045] Furthermore, in this embodiment, the portion of the case 30 facing the first direction Z1 is composed of a positive terminal 31P, a negative terminal 31N, and an external gasket 35. However, as part of the above portion, the case 30 may further have a top plate portion. The top plate portion may be located, for example, further inward from the negative terminal 31N. The top plate portion may be arranged in line with the positive terminal 31P in the axial direction Z. The top plate portion may be insulated from the negative terminal 31N. Also, if the sealing plate 33 becomes the negative terminal as described above, a top plate portion electrically insulated from the sealing plate 33 and the cylindrical wall portion 32 may be provided instead of the negative terminal 31N.

[0046] Next, the positive electrode current collector 40 will be described. As shown in Figures 1 and 3, the positive electrode current collector 40 is housed in the case 30. The positive electrode current collector 40 is positioned 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 placed between the positive electrode current collector 40 and the negative electrode terminal 31N. This electrically insulates the positive electrode current collector 40 and the negative electrode terminal 31N from each other. Furthermore, the internal gasket 36 extends to the outer circumference of the positive electrode current collector 40. As a result, the internal gasket 36 is also placed between the positive electrode current collector 40 and the cylindrical wall portion 32. Therefore, the positive electrode current collector 40 and the cylindrical wall portion 32 are electrically insulated from each other.

[0048] The positive electrode current collector 40 has a plate-like outer shape. The positive electrode current collector 40 has a roughly circular disc-like outer shape. The positive electrode current collector 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 connection portions 41 is connected to the first positive electrode 11P. Specifically, each of the multiple first positive electrode connection portions 41 is joined to the uncoated portion 111PB of the first positive electrode 11P by welding. The multiple first positive electrode connection portions 41 are spaced apart from each other. The multiple first positive electrode connection portions 41 are arranged at equal intervals in the circumferential direction centered on the terminal connection portion 43.

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

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

[0052] Multiple first fuse sections 44 are connected to each of the multiple first positive electrode connection sections 41. Each first fuse section 44 is located opposite the terminal connection section 43 when viewed from the corresponding first positive electrode connection section 41. The circumferential dimensions of the first fuse section 44 are smaller than the circumferential dimensions of the edge of the first positive electrode connection section 41 facing the outer circumference. Preferably, the thickness of the first fuse section 44 is thinner than the thickness of the first positive electrode connection section 41.

[0053] Multiple second fuse sections 45 are connected to each of the multiple second positive electrode connection sections 42. Each second fuse section 45 is located opposite the terminal connection section 43 when viewed from the corresponding second positive electrode connection section 42. The circumferential dimensions of the second fuse section 45 are smaller than the circumferential dimensions of the edge of the second positive electrode connection section 42 facing the outer circumference. Preferably, the thickness of the second fuse section 45 is thinner than the thickness of the second positive electrode connection section 42.

[0054] The outer peripheral edge portion 46 is provided on the outer peripheral edge of the positive electrode current collector member 40. The outer peripheral edge portion 46 is provided further outward from the plurality of first positive electrode connection portions 41 and the plurality of second positive electrode connection portions 42. The outer peripheral edge portion 46 is spaced apart from the plurality of first positive electrode connection portions 41 and the plurality of second positive electrode connection 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 connection portion 43 as the center.

[0055] The multiple positive electrode spokes 47 are spaced apart from each other. Each of the multiple positive electrode spokes 47 connects the terminal connection portion 43 to the outer peripheral edge portion 46. Each of the multiple positive electrode spokes 47 extends radially from the terminal connection portion 43. Each of the multiple positive electrode spokes 47 is positioned between the first positive electrode connection portion 41 and the second positive electrode connection portion 42, which 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 collector member 40 passes through the first fuse portion 44, the outer peripheral edge portion 46, and the positive electrode spoke portion 47 (see Figure 3). The first fuse portion 44 is located in the conductive path PP1 from the first positive electrode connection portion 41 to the terminal connection portion 43 in the positive electrode current collector 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 collector member 40 passes through the second fuse portion 45, the outer peripheral edge portion 46, and the positive electrode spoke portion 47 (see Figure 3). The second fuse portion 45 is located in the conductive path PP2 from the second positive electrode connection portion 42 to the terminal connection portion 43 in the positive electrode current collector member 40.

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

[0059] In this embodiment, the positive electrode current collector 40, having the configuration described above, is electrically connected to both the first positive electrode 11P and the second positive electrode 21P. As a result, the positive electrode current collector 40 is positively charged. The positive electrode current collector 40 is also electrically connected to the positive electrode terminal 31P. As a result, the positive electrode terminal 31P is positively charged.

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

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

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

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

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

[0065] Each of the multiple second negative electrode connection portions 52 is connected to the second negative electrode 21N. Specifically, each of the multiple second negative electrode connection portions 52 is joined to the uncoated portion 211NB of the second negative electrode 21N by welding. The multiple second negative electrode connection portions 52 are spaced apart from each other. The multiple second negative electrode connection portions 52 are arranged at equal intervals in the circumferential direction centered on the central portion 54. The multiple first negative electrode connection portions 51 and the multiple second negative electrode connection portions 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 both the outer peripheral edge of the sealing plate 33 and the annular gasket at the crimping portion 32d. As a result, in this embodiment, the negative electrode terminal 31N is electrically connected to the negative electrode current collector member 50 via the cylindrical wall portion 32. The case connection portion 53 is provided on the outer peripheral edge of the negative electrode current collector member 50. The case connection portion 53 is provided further outward from the plurality of first negative electrode connection portions 51 and the plurality of second negative electrode connection portions 52. The case connection portion 53 is spaced apart from the plurality of first negative electrode connection portions 51 and the plurality of 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 to overlap with the first wound electrode body 10 in the axial direction Z. The central portion 54 is provided on the inner circumference side of the plurality of first negative electrode connection portions 51 and the plurality of second negative electrode connection portions 52. The central portion 54 is connected to the plurality of first negative electrode connection portions 51 and the plurality of second negative electrode connection portions 52.

[0068] The multiple negative electrode spokes 55 are spaced apart from each other. Each of the multiple negative electrode spokes 55 connects the central portion 54 to the case connection portion 53. Each of the multiple negative electrode spokes 55 extends radially from the central portion 54. Each of the multiple negative electrode spokes 55 is positioned between the first negative electrode connection portion 51 and the second negative electrode connection portion 52, which are adjacent to each other in the circumferential direction.

[0069] Therefore, in the negative electrode current collector 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 collector 50 is not limited to the plate-shaped member described above. The negative electrode current collector 50 may be composed of multiple tab leads. One tab lead may electrically connect the first negative electrode 11N to the negative electrode terminal 31N, while other tab leads may electrically connect the second negative electrode 21N to the negative electrode terminal 31N. Furthermore, if the sealing plate 33 is the negative electrode terminal, or if 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 Figures 1 to 4, the heat insulating member 60 has a cylindrical outer shape. The heat insulating member 60 is located in the radial direction of the first wound electrode body 10. 1 wound electrode body 10 It is positioned between the second wound electrode body 20. The heat insulating member 60 is preferably made of an electrically insulating material. The heat insulating member 60 can be made of a resin composition such as foamed resin.

[0072] As described above, an energy storage cell 1 according to one embodiment of the present disclosure comprises a first wound electrode body 10, a second wound electrode body 20, a case 30, a positive electrode current collector member 40, and a negative electrode current collector member 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 winding around the first wound electrode body 10 on its outer circumference. The case 30 houses the first wound electrode body 10 and the second wound electrode body 20. The positive electrode current collector 40 is housed in the case 30. The positive electrode current collector 40 is positioned 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 collector 40 is electrically connected to both the first positive electrode 11P and the second positive electrode 21P. The negative electrode current collector 50 is housed in the case 30. The negative electrode current collector 50 is positioned 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 collector 50 is electrically connected to both the first negative electrode 11N and the second negative electrode 21N.

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

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

[0075] Since the first wound electrode body 10 is located on the inner circumference side of the second wound electrode body 20, it is relatively difficult to dissipate heat from it. However, with the above configuration, if the first wound electrode body 10 overheats, the first fuse section 44 will blow. Short circuits in the first wound electrode body 10 are suppressed. This further improves the safety of the energy storage cell 1.

[0076] Furthermore, in this embodiment, the positive electrode current collector 40 includes a second fuse portion 45. The second fuse portion 45 is located in the conductive path PP2 of the positive electrode current collector 40, from the second positive electrode connection portion 42 to the terminal connection portion 43.

[0077] According to the above configuration, if the second wound electrode body 20 collapses and an excessive current flows through the second wound electrode body 20, the second fuse section 45 will be blown. Short circuits in the second wound electrode body 20 are suppressed. This further improves the safety of the energy storage cell 1.

[0078] Furthermore, 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 collector 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 collector member 40.

[0079] With the above configuration, short circuits in the first wound electrode body 10 and the second wound electrode body 20 are suppressed individually. This further improves both the reliability and safety of the energy storage cell 1.

[0080] Furthermore, in this embodiment, the energy storage cell 1 further comprises a cylindrical heat insulating member 60. The heat insulating member 60 is located in the radial direction of the first wound electrode body 10. 1 wound electrode body 10 It is positioned between the second wound electrode body 20.

[0081] According to the above configuration, if the first wound electrode body 10 generates excessive heat, the transfer of heat from the first wound electrode body 10 to the second wound electrode body 20 can be suppressed. The first fuse 44 is blown. Short circuits in the first wound electrode body 10 are suppressed. As a result, the second wound electrode body 20 can function normally together with the positive electrode current collector 40 and the negative electrode current collector 50. This further improves the reliability of the energy storage cell 1.

[0082] 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]

[0083] 1 Energy storage cell, 10 First wound electrode body, 11N First negative electrode, 111N First negative electrode current collector foil, 111NA First negative electrode coated section, 111NB First negative electrode uncoated section, 112N First negative electrode composite layer, 11P First positive electrode, 111P First positive electrode current collector foil, 111PA First positive electrode coated section, 111PB First positive electrode uncoated section, 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 section, 211NB Second negative electrode uncoated section, 212N Second negative electrode composite layer, 21P Second positive electrode, 211P Second positive electrode current collector foil, 211PA Second positive electrode coated section, 211PB 212P Uncoated part of the second positive electrode, 22 Second separator, 30 Case, 31N Negative terminal, 31P Positive terminal, 311 Disc part, 312 Rivet part, 32 Cylindrical wall part, 32d Crimped part, 33 Sealing plate, 34 Sealing plug, 35 External gasket, 36 Internal gasket, 37 Annular gasket, 40 Positive current collector, 41 First positive connection part, 42 Second positive connection part, 43 Terminal connection part, 44 First fuse part, 45 Second fuse part, 46 Outer edge part, 47 Positive spoke part, 50 Negative current collector, 51 First negative connection part, 52 Second negative connection part, 53 Case connection part, 54 Central part, 55 Negative spoke part, 60 Heat insulation member.

Claims

1. A first wound electrode body including a first positive electrode and a first negative electrode, A second wound electrode body is formed by winding around the first wound electrode body on the outer circumference of the first wound electrode body, including a second positive electrode that is not in contact with the first positive electrode and a second negative electrode that is not in contact with the first negative electrode, with the first wound electrode body as the center. A case for housing the first wound electrode body and the second wound electrode body, A positive electrode current collector member is housed in the case and positioned on one side of the first and second wound electrode bodies in the axial direction of the first wound electrode body, and is electrically connected to both the first positive electrode and the second positive electrode. A power storage cell comprising a negative electrode current collector member housed in the case and positioned on the other side of the first wound electrode body and the second wound electrode body in the axial direction, and electrically connected to both the first negative electrode and the second negative electrode.

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

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

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

5. The energy storage cell according to any one of claims 1 to 4, further comprising a cylindrical heat insulating member disposed between the first wound electrode body and the second wound electrode body in the radial direction of the first wound electrode body.

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