Power storage cell

Abstract

To suppress a short circuit in an internal part of a cell case.SOLUTION: A power storage cell 1 based on the present disclosure comprises: a winding electrode body 10; and a cell case 20. The winding electrode body 10 contains: a positive electrode 11P; and a negative electrode 11N. The cell case 20 houses the winding electrode body 10. The cell case 20 contains: a case main body 21; and a lid 22. The case main body 21 opens to one direction. The lid 22 blocks the case main body 21. The lid 22 contains: a positive electrode external terminal 221P; a negative electrode external terminal 221N; and an insulation member 222. The positive electrode external terminal 221P is directly connected to the case main body 21. The negative electrode external terminal 221N is electrically connected to the negative electrode 11N. The insulation member 222 electrically insulates the positive electrode external terminal 221P and the negative electrode external terminal 221N. The positive electrode external terminal 221P is electrically connected to the positive electrode 11P via the case main body 21.SELECTED DRAWING: Figure 1

Description

[Technical field]

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

[0002] Patent Document 1 discloses a conventional non-aqueous electrolyte secondary battery as a storage cell. In this non-aqueous electrolyte secondary battery, a negative electrode and a positive electrode are wound with a porous separator interposed therebetween and inserted into a cylindrical container. Leads are taken out from the positive electrode and the negative electrode. The cylindrical container is made of stainless steel. A container lid is welded to the opening of the container at its periphery. A positive electrode terminal and a negative electrode terminal are provided on a part of the container lid. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 3322321 Summary of the Invention [Problem to be solved by the invention]

[0004] When both the positive and negative terminals are provided on the lid, as in the case of the storage cell disclosed in Patent Document 1, the positive and negative leads in the container are relatively close to each other, which may cause the leads to come into contact with each other and cause a short circuit, for example.

[0005] The present disclosure has been made in consideration of the above problems, and has an object to provide an energy storage cell that can suppress short circuits inside the cell casing. [Means for solving the problem]

[0006] A power storage cell according to the present disclosure includes a wound electrode body and a cell case. The wound electrode body includes a positive electrode and a negative electrode. The cell case houses the wound electrode body. The cell case includes a case body and a lid. The case body is open in one direction. The lid closes the case body. The lid includes a positive electrode external terminal, a negative electrode external terminal, and an insulating member. The positive electrode external terminal is directly joined to the case body. The negative electrode external terminal is electrically connected to the negative electrode. The insulating member electrically insulates the positive electrode external terminal from the negative electrode external terminal. The positive electrode external terminal is electrically connected to the positive electrode via the case body.

[0007] According to the above configuration, there is no need to provide a positive current collecting member such as a tab lead between the wound electrode body and the lid. Therefore, the positive current collecting member does not come into contact with a negatively charged member between the wound electrode body and the lid. As a result, a short circuit inside the cell case can be suppressed. Effect of the Invention

[0008] According to the present disclosure, short circuits inside the cell casing can be suppressed. [Brief description of the drawings]

[0009] [Figure 1] 1 is a cross-sectional view showing a storage cell according to a first embodiment. [Diagram 2] FIG. 2 is a partially exploded perspective view of a wound electrode body. [Diagram 3] 1 is an exploded perspective view partially illustrating a storage cell according to a first embodiment. FIG. [Figure 4] 4 is another exploded perspective view partially showing the electricity storage cell according to the first embodiment. FIG. [Diagram 5] FIG. 4 is a cross-sectional view showing a storage cell according to a second embodiment. [Figure 6] FIG. 11 is an exploded perspective view partially showing a storage cell according to a second embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Hereinafter, a storage cell according to each 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] (Embodiment 1) Fig. 1 is a cross-sectional view showing an energy storage cell according to embodiment 1. As shown in Fig. 1, the energy storage cell 1 according to embodiment 1 of the present disclosure includes a wound electrode body 10, a cell case 20, a negative electrode current collecting member 30, and an internal gasket 40.

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

[0013] The wound electrode body 10 includes a positive electrode 11P, a negative electrode 11N, and a separator 12. The positive electrode 11P and the negative electrode 11N have a sheet-like outer shape. The wound electrode body 10 is composed of an electrode plate group in which the positive electrode 11P and the negative electrode 11N are wound with the separator 12 interposed therebetween.

[0014] Separator 12 is provided between positive electrode 11P and negative electrode 11N. Separator 12 separates positive electrode 11P from negative electrode 11N while allowing ions (e.g., lithium ions) to move between positive electrode 11P (positive electrode active material) and negative electrode 11N (negative electrode active material).

[0015] Positive electrode 11P includes positive electrode current collector foil 111P and positive electrode mixture layer 112P. Positive electrode current collector foil 111P is made of aluminum or an aluminum alloy.

[0016] The positive electrode mixture layer 112P is laminated on the positive electrode current collector foil 111P. Specifically, the positive electrode mixture layer 112P is coated on both radial surfaces of the positive electrode current collector foil 111P (positive electrode coated portion 111PA described later). The positive electrode mixture layer 112P is in close contact with the separator 12. In this embodiment, the outer surface in the radial direction of the wound electrode body 10 is composed of the positive electrode 11P. Specifically, the outer surface in the radial direction of the wound electrode body 10 is composed of the positive electrode current collector foil 111P. That is, the positive electrode mixture layer 112P is not laminated on the outer surface of the positive electrode current collector foil 111P located outermost in the radial direction of the wound electrode body 10.

[0017] Positive electrode mixture layer 112P is formed by applying a positive electrode slurry to the surface of positive electrode current collector foil 111P and drying it. The positive electrode slurry is a slurry prepared by kneading the materials of positive electrode mixture layer 112P (positive electrode active material, binder, etc.) with a solvent. The thickness of positive electrode mixture layer 112P is, for example, 0.1 μm or more and 1000 μm or less.

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

[0019] The positive electrode uncoated portion 111PB is an exposed portion of the positive electrode current collector foil 111P that is not covered by the positive electrode composite layer 112P. The positive electrode uncoated portion 111PB is located on the second direction Z2 side of the positive electrode coated portion 111PA. The second direction Z2 is the opposite direction to the first direction Z1 along the axial direction Z. Specifically, the positive electrode uncoated portion 111PB protrudes in the second direction Z2 from the positive electrode coated portion 111PA. The positive electrode uncoated portion 111PB is bent radially inward about the winding axis α.

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

[0021] Negative electrode 11N includes negative electrode current collector foil 111N and negative electrode composite layer 112N. Negative electrode current collector foil 111N has a sheet-like outer shape. Negative electrode current collector foil 111N is made of, for example, copper.

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

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

[0024] The negative electrode uncoated portion 111NB is a portion that is not coated with the negative electrode composite layer 112N. In other words, the negative electrode uncoated portion 111NB is a portion of the negative electrode current collector foil 111N that is not covered with the negative electrode composite layer 112N and is exposed. The negative electrode uncoated portion 111NB is located on the first direction Z1 side along the axial direction from the negative electrode coated portion 111NA. The negative electrode uncoated portion 111NB protrudes from the negative electrode coated portion 111NA to one side in the axial direction Z of the wound electrode body 10. Specifically, the negative electrode uncoated portion 111NB protrudes from the negative electrode coated portion 111NA to the first direction Z1 side along the axial direction Z. The negative electrode uncoated portion 111NB is bent radially inward around the winding axis α.

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

[0026] Next, the cell case 20 will be described. FIG. 3 is one exploded perspective view partially showing the energy storage cell according to embodiment 1. FIG. 4 is another exploded perspective view partially showing the energy storage cell according to embodiment 1. As shown in FIGS. 1, 3, and 4, the cell case 20 houses the wound electrode body 10. The cell case 20 includes a case body 21 and a lid 22.

[0027] The case body 21 is open in one direction. Specifically, the case body 21 is open on the first direction Z1 side. The case body 21 has a cylindrical shape with a bottom. The case body 21 is made of aluminum or an aluminum alloy.

[0028] The case body 21 is directly joined to the positive current collector foil 111P. Specifically, the case body 21 is joined to the positive uncoated portion 111PB (the multiple extending portions 111NC) by welding. On the second direction Z2 side of the wound electrode body 10, the case body 21 is directly joined to the positive current collector foil 111P.

[0029] The case body 21 includes a cylindrical wall portion 211 and a bottom portion 212. The cylindrical wall portion 211 is provided so as to cover the outer peripheral side of the wound electrode body 10. The cylindrical wall portion 211 covers the entire outer peripheral side of the wound electrode body 10. The cylindrical wall portion 211 has a cylindrical shape. The cylindrical wall portion 211 may have a rectangular cylindrical outer shape. The inner peripheral surface of the cylindrical wall portion 211 is in close contact with the positive electrode 11P constituting the outer surface in the radial direction of the wound electrode body 10. Specifically, the inner peripheral surface of the cylindrical wall portion 211 is in contact with the positive electrode current collector foil 111P. However, the inner peripheral surface of the cylindrical wall portion 211 may be in contact with the positive electrode composite layer 112P. The inner peripheral surface of the cylindrical wall portion 211 may be in contact with the separator 12.

[0030] The bottom 212 is disposed on one side in the axial direction Z as viewed from the wound electrode body 10. Specifically, the bottom 212 is disposed on the second direction Z2 side along the axial direction Z as viewed from the wound electrode body 10. The bottom 212 is connected to an end of the cylindrical wall portion 211 on the second direction Z2 side. In this embodiment, the bottom 212 is integrally formed with the cylindrical wall portion 211. The bottom 212 may be molded as a separate member from the cylindrical wall portion 211. At this time, the outer peripheral edge of the bottom 212 may be joined to the cylindrical wall portion 211 by laser welding or the like. The bottom 212 is electrically connected to the cylindrical wall portion 211.

[0031] The bottom 212 is joined to the positive electrode uncoated portion 111PB by welding from the outside of the cell case 20. This causes the bottom 212 to be positively charged. The cylindrical wall portion 211 connected to the bottom 212 is also positively charged. Note that the bottom 212 of the energy storage cell 1 can also be used as a positive electrode terminal.

[0032] The bottom portion 212 has an annular ridge portion 212A, a plurality of radial ridge portions 212B, and a plurality of welded portions 212C. When viewed from the axial direction Z, the annular ridge portion 212A extends in an annular shape centered on the winding axis α of the wound electrode body 10. The annular ridge portion 212A protrudes toward the first direction Z1. That is, the annular ridge portion 212A protrudes toward the wound electrode body 10. The annular ridge portion 212A is in contact with the positive electrode uncoated portion 111PB of the positive electrode 11P.

[0033] The multiple radial convex streaks 212B are arranged so as to be spaced apart from each other in the circumferential direction centered on the winding axis α of the wound electrode body 10 as viewed from the axial direction Z. The multiple radial convex streaks 212B are arranged at equal intervals in the circumferential direction.

[0034] Each of the multiple radial ridge portions 212B extends in a radial direction centered on the winding axis α of the wound electrode body 10. The radial ridge portion 212B is continuous with the annular ridge portion 212A.

[0035] The radial ridge portion 212B protrudes toward the first direction Z1. That is, the radial ridge portion 212B protrudes toward the wound electrode body 10. The radial ridge portion 212B is in contact with the positive electrode uncoated portion 111PB of the positive electrode 11P.

[0036] The welds 212C are portions of the bottom 212 that are joined to the positive electrode uncoated portion 111PB by welding. The welds 212C are formed by laser welding from the outside of the cell case 20. The welds 212C are formed on the annular ridge portion 212A. On the annular ridge portion 212A, the welds 212C are formed to extend along the circumferential direction. The welds 212C are formed on each of the radial ridge portions 212B. On the radial ridge portion 212B, the welds 212C are formed to extend along the radial direction. The annular ridge portion 212A and the radial ridge portions 212B may be thinner than other portions of the bottom 212. This makes it easier to form the welds 212C.

[0037] A through hole 212h is formed in the bottom portion 212. The through hole 212h may be used to inject an electrolyte (not shown) contained in the cell case 20. The through hole 212h is formed in the center of the bottom portion 212 when viewed from the axial direction Z.

[0038] The sealing plug 213 is inserted into the through-hole 212h of the bottom 212. This fixes the sealing plug 213 to the bottom 212. The sealing plug 213 and the through-hole 212h can function as a pressure relief valve for releasing the pressure inside the cell casing 20 when the pressure inside the cell casing 20 becomes excessively high.

[0039] The lid 22 closes the case body 21. The lid 22 includes a positive external terminal 221P, a negative external terminal 221N, and an insulating member 222.

[0040] The positive external terminal 221P has a plate-like outer shape. Specifically, the positive external terminal 221P has a substantially disk-like outer shape. The positive external terminal 221P is provided so as to be perpendicular to the axial direction Z. A through hole 221Ph is provided in the positive external terminal 221P. Therefore, the positive external terminal 221P has an annular outer shape when viewed from the axial direction Z. The positive external terminal 221P is made of aluminum or an aluminum alloy.

[0041] The positive electrode external terminal 221P is directly joined to the case body 21 (cylindrical wall portion 211). As a result, the positive electrode external terminal 221P connected to the case body 21 (cylindrical wall portion 211) is also positively charged. Therefore, in this embodiment, the positive electrode external terminal 221P is electrically connected to the positive electrode 11P via the case body 21. The positive electrode external terminal 221P may be joined to the cylindrical wall portion 211 by crimping an end of the cylindrical wall portion 211.

[0042] The positive external terminal 221P is joined to the end of the case body 21 (the cylindrical wall portion 211) on the first direction Z1 side by welding such as laser welding, thereby forming an annular welded portion 22A between the cylindrical wall portion 211 and the positive external terminal 221P.

[0043] The negative electrode external terminal 221N is electrically connected to the negative electrode 11N via a negative electrode current collecting member 30 (described later). The negative electrode external terminal 221N is made of, for example, aluminum, copper, or stainless steel.

[0044] The negative electrode external terminal 221N is disposed on the first direction Z1 side of the wound electrode body 10. The negative electrode external terminal 221N includes a disk portion 221NA and a rivet portion 221NB.

[0045] The disk portion 221NA is exposed to the outside. The disk portion 221NA is located on the opposite side of the wound electrode body 10 from the positive external terminal 221P.

[0046] The rivet portion 221NB is connected to the disk portion 221NA. The rivet portion 221NB extends from the center of the disk portion 221NA when viewed from the axial direction Z. The rivet portion 221NB is located approximately on the winding axis α of the wound electrode body 10. The rivet portion 221NB extends toward the second direction Z2 when viewed from the disk portion 221NA. The rivet portion 221NB is inserted into the through hole 221Ph. The rivet portion 221NB extends into the inside of the cell case 20.

[0047] The insulating member 222 electrically insulates the positive external terminal 221P and the negative external terminal 221N. The insulating member 222 is disposed between the positive external terminal 221P and the negative external terminal 221N. The insulating member 222 covers the surface of the disk portion 221NA on the second direction Z2 side. The rivet portion 221NB penetrates the insulating member 222 in the axial direction Z. The insulating member 222 covers the inner surface in the radial direction of the through hole 221Ph of the positive external terminal 221P.

[0048] Next, the negative current collecting member 30 will be described. As shown in Fig. 1 and Fig. 4, the negative current collecting member 30 is disposed in the cell case 20. The negative current collecting member 30 is disposed on the first direction Z1 side of the wound electrode body 10. In this embodiment, the negative current collecting member 30 has a plate-like outer shape, but may be a tab-shaped lead.

[0049] The negative electrode current collecting member 30 is provided to electrically connect the negative electrode 11N and the negative electrode external terminal 221N. The negative electrode current collecting member 30 is joined to the negative electrode uncoated portion 111NB of the negative electrode 11N by welding. As a result, the negative electrode current collecting member 30 is negatively charged. The negative electrode current collecting member 30 is joined to an end of the rivet portion 221NB of the negative electrode external terminal 221N on the second direction Z2 side by welding. As a result, the negative electrode external terminal 221N is negatively charged.

[0050] The negative current collecting member 30 has a substantially circular disk-like shape and includes a central portion 31, an outer peripheral edge portion 32, a plurality of spokes 33, and a plurality of pieces .

[0051] The central portion 31 is positioned so as to overlap the rivet portion 221NB of the negative external terminal 221N when viewed from the axial direction Z. The central portion 31 is joined to the rivet portion 221NB of the negative external terminal 221N by welding.

[0052] The outer peripheral edge portion 32 is provided on the outer peripheral edge of the negative electrode current collecting member 30. The outer peripheral edge portion 32 is located on the outer peripheral side of the central portion 31. The outer peripheral edge portion 32 extends in an annular shape with the central portion 31 as the center. The outer peripheral edge portion 32 may be in contact with the negative electrode uncoated portion 111NB of the negative electrode 11N. However, the outer peripheral edge portion 32 is not joined to the negative electrode uncoated portion 111NB.

[0053] The multiple spokes 33 are spaced apart from one another. The multiple spokes 33 are arranged at equal intervals in the circumferential direction centered on the central portion 31. The spokes 33 connect the central portion 31 and the outer peripheral edge portion 32. The spokes 33 have an outer shape such that the width dimension is approximately equal from the central portion 31 to the outer peripheral edge portion 32.

[0054] The pieces 34 are spaced apart from one another. The pieces 34 are arranged at equal intervals in the circumferential direction centered on the central portion 31. The spokes 33 and the pieces 34 are arranged such that the spokes 33 and the pieces 34 alternate in the circumferential direction centered on the central portion 31.

[0055] The piece portion 34 extends from the outer peripheral edge portion 32 toward the central portion 31. The piece portion 34 is connected to the negative electrode 11N. Specifically, the piece portion 34 is joined to the negative electrode uncoated portion 111NB of the negative electrode 11N by welding. Fig. 4 shows a schematic diagram of a path PN on the negative electrode current collecting member 30 from the joint portion between the piece portion 34 and the negative electrode uncoated portion 111NB to the joint portion between the central portion 31 and the rivet portion 221NB.

[0056] The piece 34 has a sectorial portion 341 and a neck portion 342. The sectorial portion 341 is joined to the negative electrode uncoated portion 111NB of the negative electrode 11N by welding. The tip of the sectorial portion 341 faces the central portion 31. The sectorial portion 341 extends toward the outer peripheral edge portion 32 so as to follow two adjacent spokes 33 on both sides in the circumferential direction. This makes the surface area of ​​the sectorial portion 341 relatively large, facilitating welding to the negative electrode uncoated portion 111NB of the negative electrode 11N.

[0057] The neck portion 342 connects the outer peripheral edge portion 32 and the sectorial portion 341. The neck portion 342 may contact the negative electrode uncoated portion 111NB of the negative electrode 11N. However, the neck portion 342 is not joined to the negative electrode uncoated portion 111NB of the negative electrode 11N. The circumferential dimension of the neck portion 342 is smaller than the circumferential dimension of the outer peripheral edge of the sectorial portion 341. This makes it easier for the piece portion 34 to bend at the neck portion 342.

[0058] Here, an example of a method for welding the central portion 31 and the rivet portion 221NB in ​​this embodiment will be described. First, before the central portion 31 is welded to the rivet portion 221NB, the fan-shaped portion 341 of the piece portion 34 is welded to the negative electrode uncoated portion 111NB of the negative electrode 11N in advance. Next, a welding device is inserted from the second direction Z2 side of the wound electrode body 10 along the winding axis α of the wound electrode body 10. Then, while the welding device is pressed against the central portion 31 from the second direction Z2 side, the welding device welds the central portion 31 and the rivet portion 221NB to each other. At this time, on the path PN, the connection portion between the spoke 33 and the central portion 31 and the connection portion between the spoke 33 and the outer circumferential edge portion 32 are largely deflected. This allows the central portion 31 to be easily displaced in the axial direction Z relative to the piece portion 34. Therefore, even if a welding device is pressed against the central portion 31, the bond between the piece portion 34 and the negative electrode uncoated portion 111NB is prevented from being destroyed due to displacement of the central portion 31. This in turn facilitates connection between the negative electrode current collecting member 30 and the negative electrode external terminal 221N.

[0059] The internal gasket 40 is housed in the cell case 20. The internal gasket 40 covers the surface of the positive electrode external terminal 221P on the second direction Z2 side. The internal gasket 40 is formed of an insulating material. Therefore, the internal gasket 40 insulates the wound electrode body 10 from the positive electrode external terminal 221P. The rivet portion 221NB penetrates the internal gasket 40 in the axial direction Z.

[0060] Specifically, the internal gasket 40 is disposed between the negative current collecting member 30 and the positive external terminal 221P. As a result, the negative current collecting member 30 and the positive external terminal 221P are electrically insulated from each other. The internal gasket 40 also extends to the outer circumferential side of the negative current collecting member 30. As a result, the internal gasket 40 is also disposed between the negative current collecting member 30 and the cylindrical wall portion 211. As a result, the negative current collecting member 30 and the cylindrical wall portion 211 are electrically insulated from each other.

[0061] As described above, the energy storage cell 1 according to the first embodiment of the present disclosure includes the wound electrode body 10 and the cell case 20. The wound electrode body 10 includes a positive electrode 11P and a negative electrode 11N. The cell case 20 accommodates the wound electrode body 10. The cell case 20 includes a case body 21 and a lid 22. The case body 21 is open in one direction. The lid 22 closes the case body 21. The lid 22 includes a positive electrode external terminal 221P, a negative electrode external terminal 221N, and an insulating member 222. The positive electrode external terminal 221P is directly joined to the case body 21. The negative electrode external terminal 221N is electrically connected to the negative electrode 11N. The insulating member 222 electrically insulates the positive electrode external terminal 221P from the negative electrode external terminal 221N. The positive electrode external terminal 221P is electrically connected to the positive electrode 11P via the case body 21.

[0062] According to the above configuration, there is no need to provide a positive current collecting member such as a tab lead between the wound electrode body 10 and the lid 22. Therefore, the positive current collecting member does not come into contact with a negatively charged member between the wound electrode body 10 and the lid 22. As a result, a short circuit inside the cell case 20 can be suppressed.

[0063] In this embodiment, the positive electrode 11P includes a positive electrode current collector foil 111P and a positive electrode composite layer 112P. The positive electrode current collector foil 111P is made of aluminum or an aluminum alloy. The positive electrode composite layer 112P is laminated on the positive electrode current collector foil 111P. The case body 21 is directly joined to the positive electrode current collector foil 111P. The case body 21 is made of aluminum or an aluminum alloy. The positive electrode external terminal 221P is made of aluminum or an aluminum alloy.

[0064] According to the above configuration, the case body 21 is directly joined to the positive current collector foil 111P, so that the weight of the case body 21 can be reduced. Since the case body 21 is made of aluminum or an aluminum alloy, the weight of the case body 21 can be further reduced. Since the case body 21 and the positive current collector foil 111P are both made of aluminum or an aluminum alloy and are directly joined to each other, the contact resistance can be reduced. Furthermore, since the positive external terminal 221P and the case body 21 are made of aluminum or an aluminum alloy, the contact resistance can be further reduced.

[0065] (Embodiment 2) Next, a description will be given of a storage cell according to embodiment 2 of the present disclosure. The storage cell according to embodiment 2 of the present disclosure differs from embodiment 1 of the present disclosure in that it further includes a positive electrode current collecting member. Therefore, description will not be repeated of configurations and effects similar to those of embodiment 1 of the present disclosure.

[0066] Fig. 5 is a cross-sectional view showing the storage cell according to embodiment 2. Fig. 6 is an exploded perspective view partially showing the storage cell according to embodiment 2.

[0067] As shown in Fig. 5 and Fig. 6, the power storage cell 1a further includes a positive current collecting member 50. The positive current collecting member 50 is disposed between the wound electrode body 10 and the case body 21 on the side opposite to the lid 22 as viewed from the wound electrode body 10. The positive current collecting member 50 is made of aluminum or an aluminum alloy. The positive current collecting member 50 is directly joined to the positive current collecting foil 111P. The positive current collecting member 50 is connected to the case body 21.

[0068] According to the above configuration, while suppressing an internal short circuit between the wound electrode body 10 and the lid 22, the positive current collecting member 50 increases the degree of freedom in the manner of connection between the case body 21 and the positive electrode 11P. Note that the positive current collecting member 50, the positive current collecting foil 111P, and the case body 21 are all made of aluminum or an aluminum alloy, and are connected to each other, thereby suppressing an increase in contact resistance.

[0069] In this embodiment, the positive current collecting member 50 has a plate-like outer shape, but may be a tab-like lead. The positive current collecting member 50 is joined to the positive electrode uncoated portion 111PB of the positive electrode 11P by welding. As a result, the positive current collecting member 50 is positively charged. The positive current collecting member 50 may or may not be joined to the case main body 21 (bottom 212) by welding. However, the positive current collecting member 50 is in close contact with the bottom 212. As a result, the case main body 21 is also positively charged.

[0070] The positive current collecting member 50 includes a central portion 51, an outer peripheral edge portion 52, a plurality of spokes 53, and a plurality of pieces 54, similar to the negative current collecting member 30. However, in the positive current collecting member 50, each piece 54 extends from the central portion 51 toward the outer peripheral edge portion 52. The pieces 54 are connected to the positive electrode 11P. Specifically, the pieces 54 are joined to the positive electrode uncoated portion 111PB of the positive electrode 11P by welding.

[0071] 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 embodiments described above, and is intended to include all modifications within the meaning and scope of the claims. [Explanation of symbols]

[0072] 1,1a storage cell, 10 wound electrode body, 11N negative electrode, 111N negative electrode current collector foil, 111NA negative electrode coated portion, 111NB negative electrode uncoated portion, 112N negative electrode composite layer, 11P positive electrode, 111P positive electrode current collector foil, 111PA positive electrode coated portion, 111PB positive electrode uncoated portion, 112P positive electrode composite layer, 12 separator, 20 cell case, 21 case body, 211 cylindrical wall portion, 212 bottom portion, 212A annular ridge portion, 212B radial ridge portion, 212C welded portion, 213 sealing plug, 22 lid, 22A annular welded portion, 221N negative electrode external terminal, 221NA disk portion, 221NB rivet portion, 221P positive electrode external terminal, 222 Insulating member, 30 negative electrode current collecting member, 31 central portion, 32 outer peripheral edge portion, 33 spokes, 34 piece portion, 341 sector portion, 342 neck portion, 40 internal gasket, 50 positive electrode current collecting member, 51 central portion, 52 outer peripheral edge portion, 53 spokes, 54 piece portion.

Claims

1. A wound electrode body including a positive electrode and a negative electrode; A cell case that houses the wound electrode body, The cell case includes a case body that opens in one direction and a lid that closes the case body, the lid includes a positive electrode external terminal directly joined to the case body, a negative electrode external terminal electrically connected to the negative electrode, and an insulating member that electrically insulates the positive electrode external terminal from the negative electrode external terminal, The positive electrode external terminal is electrically connected to the positive electrode via the case body.

2. The positive electrode includes a positive electrode current collector foil and a positive electrode mixture layer, The positive electrode current collector foil is made of aluminum or an aluminum alloy, the positive electrode mixture layer is laminated on the positive electrode current collector foil, the case body is directly joined to the positive electrode current collector foil, The case body is made of aluminum or an aluminum alloy. The energy storage cell according to claim 1 , wherein the positive electrode external terminal is formed from aluminum or an aluminum alloy.

3. The battery further includes a positive electrode current collecting member disposed between the wound electrode body and the case body on the opposite side of the lid from the wound electrode body, The positive electrode includes a positive electrode current collector foil and a positive electrode mixture layer, The positive electrode current collector foil is made of aluminum or an aluminum alloy, the positive electrode mixture layer is laminated on the positive electrode current collector foil, The positive electrode current collecting member is formed of aluminum or an aluminum alloy, the positive electrode current collecting member is directly joined to the positive electrode current collecting foil, The positive electrode current collecting member is connected to the case body, The case body is made of aluminum or an aluminum alloy. The energy storage cell according to claim 1 , wherein the positive electrode external terminal is formed from aluminum or an aluminum alloy.

Images