Electric storage cell

Abstract

To provide a power storage cell in which, when a plurality of metal pieces are provided at an end of a wound electrode body in an axial direction, penetration of an electrolyte into a separator can be prevented from being hindered by the metal pieces.SOLUTION: The electric storage cell 100 includes a wound electrode body 1 that includes a positive electrode plate 10 (first electrode), a negative electrode plate 20 (second electrode), and separators 30. The positive electrode plate 10 includes a plurality of partial side 1a (metal pieces) provided on the side 11d at the end in the Z direction (axial direction). A through-hole 11d (opening) is formed in each partial 11f.SELECTED DRAWING: Figure 3

Description

[Technical Field]

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

[0002] U.S. Patent Application Publication No. 2020 / 0144676 (Patent Document 1) discloses a cell in which a first substrate, a separator, and a second substrate are wound around a central axis. The first substrate has a tabless structure without conductive tabs. Multiple metal pieces are provided at the axial end of the first substrate as conductive portions. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] US Patent Publication No. 2020 / 0144676 Summary of the Invention [Problem to be solved by the invention]

[0004] In the cell of Patent Document 1, as described above, multiple metal pieces are provided at the axial end of the first substrate. The multiple metal pieces are provided so as to cover the axial end of the cell. Therefore, the metal pieces may hinder the flow of the electrolyte, making it difficult for the electrolyte to penetrate into the separator.

[0005] The present disclosure has been made to solve the above-mentioned problems, and its purpose is to provide a storage cell that can prevent the penetration of electrolyte into the separator from being hindered by metal pieces when multiple metal pieces are provided at the ends of a wound electrode body in the axial direction. [Means for solving the problem]

[0006] A first aspect of the present disclosure provides an energy storage cell including a wound electrode assembly including a first electrode, a second electrode, and a separator disposed between the first and second electrodes, and a case that houses the wound electrode assembly. The wound electrode assembly is configured such that the first electrode, the second electrode, and the separator are wound around the winding axis. At least one of the first electrode and the second electrode includes a plurality of metal pieces provided at an end of the wound electrode assembly in the axial direction along which the winding axis extends. At least one of the plurality of metal pieces has at least one opening formed therein. The opening includes both a hole and a notch.

[0007] In the energy storage cell according to the first aspect of the present disclosure, as described above, at least one of the metal pieces has at least one opening formed therein. This allows the electrolyte to flow to the separator side through the opening. As a result, it is possible to prevent the metal piece from interfering with the penetration of the electrolyte into the separator.

[0008] In the energy storage cell according to the first aspect, the at least one opening preferably includes a plurality of openings. With this configuration, the electrolyte can flow to the separator side through the plurality of openings. As a result, it is possible to further prevent the penetration of the electrolyte into the separator from being hindered by metal pieces.

[0009] In the energy storage cell according to the first aspect, the at least one opening is preferably provided in each of the plurality of metal pieces. With this configuration, the electrolyte can flow to the separator side through the opening provided in each of the plurality of metal pieces. This makes it possible to further suppress the metal pieces from interfering with the penetration of the electrolyte into the separator, compared to when openings are provided only in some of the plurality of metal pieces.

[0010] In the energy storage cell according to the first aspect, each of the plurality of metal pieces preferably includes an axis crossing portion extending intersecting the axial direction. The at least one opening is provided in the axis crossing portion. With this configuration, since the axis crossing portion is provided so as to extend intersecting the axial direction, the electrolyte flowing from one side in the axial direction of the wound electrode body can easily flow through the opening.

[0011] In the energy storage cell according to the first aspect, the first electrode preferably includes a first current collector and a first electrode material layer coated on a portion of the first current collector and facing the separator in the radial direction of the wound electrode body. The first current collector has a first coated portion coated with the first electrode material layer and a first uncoated portion located at an end on one side of the first coated portion in the axial direction and not coated with the first electrode material layer. The first uncoated portion includes a plurality of metal pieces. This configuration allows the electrolyte to flow through openings provided in the first uncoated portion not coated with the first electrode material layer. This makes it possible to prevent the first electrode material layer from peeling off due to the flow of the electrolyte.

[0012] In the energy storage cell according to the first aspect, the second electrode preferably includes a second current collector and a second electrode material layer coated on a portion of the second current collector and facing the separator in the radial direction of the wound electrode body. The second current collector has a second coated portion coated with the second electrode material layer and a second uncoated portion located at the other end of the second coated portion in the axial direction and not coated with the second electrode material layer. The second uncoated portion includes a plurality of metal pieces. This configuration allows the electrolyte to flow through openings provided in the second uncoated portion not coated with the second electrode material layer. This makes it possible to prevent the second electrode material layer from peeling off due to the flow of the electrolyte.

[0013] In the energy storage cell according to the first aspect, the at least one opening preferably includes at least one of a through hole and a notch. With this configuration, the electrolyte can easily flow through the through hole and the notch.

[0014] A second aspect of the present disclosure provides an energy storage cell including a wound electrode assembly including a first electrode, a second electrode, and a separator disposed between the first and second electrodes, and a case that houses the wound electrode assembly. The wound electrode assembly is configured such that the first electrode, the second electrode, and the separator are wound around the winding axis. At least one of the first electrode and the second electrode includes a plurality of metal pieces provided at an end of the wound electrode assembly in the axial direction along which the winding axis extends. Each of the plurality of metal pieces includes a radial portion that extends in a predetermined direction along the radial direction of the wound electrode assembly. Some of the radial portions of the plurality of metal pieces have a length in the predetermined direction that is smaller than the remaining radial portions of the plurality of metal pieces.

[0015] In the energy storage cell according to the second aspect of the present disclosure, as described above, some of the metal pieces have a radial length in a predetermined direction that is shorter than the remaining metal pieces. This allows the radial lengths of some of the metal pieces to be relatively short, forming gaps between the metal pieces. As a result, the electrolyte can flow through these gaps toward the separator. This prevents the metal pieces from interfering with the penetration of the electrolyte into the separator. [Effects of the Invention]

[0016] According to the present disclosure, when a plurality of metal pieces are provided at the ends of the wound electrode body in the axial direction, it is possible to prevent the metal pieces from interfering with the penetration of the electrolyte into the separator. [Brief explanation of the drawings]

[0017] [Figure 1] 1 is a cross-sectional view showing the configuration of a storage cell according to a first embodiment. [Figure 2] FIG. 1 is a schematic perspective view showing the configuration of a wound electrode body according to a first embodiment. [Figure 3] FIG. 2 is a partial enlarged view of the positive electrode side of FIG. [Figure 4] FIG. 2 is a partially enlarged view of the negative electrode side of FIG. [Figure 5] FIG. 2 is a plan view showing the configuration of a positive electrode plate according to the first embodiment. [Figure 6] FIG. 2 is a plan view showing the configuration of a negative electrode plate according to the first embodiment. [Figure 7] FIG. 6 is a partially enlarged view of the vicinity of an uncoated portion of the positive electrode in FIG. 5. [Figure 8] FIG. 10 is a cross-sectional view showing the configuration of the positive electrode side of a wound electrode body according to a second embodiment. [Figure 9] FIG. 10 is a cross-sectional view showing the configuration of the negative electrode side of a wound electrode body according to a second embodiment. [Figure 10] FIG. 4 is a partially enlarged view of the vicinity of an uncoated portion of a positive electrode according to a modified example of the first embodiment. [Figure 11] FIG. 4 is a plan view showing the configuration of a positive electrode plate according to a modified example of the first embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0018] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. In the drawings, the same or corresponding parts are designated by the same reference numerals, and description thereof will not be repeated.

[0019] [First embodiment] 1 is a cross-sectional view showing the overall configuration of an energy storage cell 100 according to an embodiment of the present disclosure. The energy storage cell 100 is, for example, a lithium-ion battery mounted on a vehicle. Note that the uses and types of the energy storage cell 100 are not limited to the above examples.

[0020] The energy storage cell 100 includes a wound electrode assembly 1, a case 2, a positive electrode terminal 3, a positive electrode current collector plate 4, an external gasket 5, an internal gasket 6, and a negative electrode current collector plate .

[0021] The wound electrode body 1 is housed in a case 2. The case 2 has a cylindrical shape. That is, the energy storage cell 100 is a cylindrical battery. The case 2 is made of copper or aluminum.

[0022] The wound electrode body 1 includes a positive electrode plate 10, a negative electrode plate 20, and a separator 30. The separator 30 is provided between the positive electrode plate 10 and the negative electrode plate 20. The separator 30 separates the positive electrode plate 10 and the negative electrode plate 20 while allowing ions (e.g., lithium ions) to move between the positive electrode plate 10 (positive electrode active material) and the negative electrode plate 20 (negative electrode active material). The wound electrode body 1 is composed of an electrode plate group in which the positive electrode plate 10 and the negative electrode plate 20 are wound with the separator 30 interposed therebetween. The positive electrode plate 10 and the negative electrode plate 20 are examples of the "first electrode" and the "second electrode," respectively, of the present disclosure.

[0023] As shown in Fig. 2, the wound electrode body 1 is formed by winding a positive electrode plate 10, a negative electrode plate 20, and a separator 30 around a winding axis α. In Fig. 2, the wound electrode body 1 is shown in a slightly unwound state so that the wound state of the wound electrode body 1 can be easily understood.

[0024] 1, the positive electrode terminal 3 includes a disk portion 3a and a rivet portion 3b. The rivet portion 3b is connected to the disk portion 3a. The rivet portion 3b is provided so as to extend from the center of the disk portion 3a toward the Z2 side. The positive electrode terminal 3 is made of aluminum.

[0025] 3, the disk portion 3a is disposed on the upper surface 2a (surface on the Z1 side) of the case 2. A through hole 2b is provided in the upper surface 2a of the case 2. The rivet portion 3b extends from the disk portion 3a, which is disposed outside the case 2, through the through hole 2b to the inside of the case 2.

[0026] The positive current collector 4 is housed in the case 2. The positive current collector 4 is welded to a positive electrode uncoated portion 11b (described later) of the positive plate 10 on the Z1 side of the wound electrode body 1. As a result, the positive current collector 4 is positively charged. The positive current collector 4 is welded to an end 3c on the Z2 side of the rivet portion 3b. As a result, the positive terminal 3 is positively charged.

[0027] The external gasket 5 is disposed between the disk portion 3a of the positive electrode terminal 3 and the upper surface 2a of the case 2. This insulates the positive electrode terminal 3 from the case 2.

[0028] The internal gasket 6 is disposed inside the case 2, between the case 2 and the positive current collector plate 4. This insulates the case 2 from the positive current collector plate 4. The rivet portion 3b penetrates the internal gasket 6 and comes into contact with the positive current collector plate 4.

[0029] The positive electrode plate 10 includes a positive electrode current collector 11 and a positive electrode composite layer 12. The positive electrode composite layer 12 is applied to both surfaces in the radial direction (R direction) of the positive electrode current collector 11 (a positive electrode coated portion 11a described below). The positive electrode composite layer 12 faces the separator 30 in the R direction. The positive electrode current collector 11 and the positive electrode composite layer 12 are examples of a "first current collector" and a "first electrode material layer," respectively.

[0030] Positive electrode current collector 11 is made of, for example, aluminum. Positive electrode mixture layer 12 is formed by applying a positive electrode slurry to the surface of positive electrode current collector 11 and drying it. The positive electrode slurry is prepared by kneading materials for positive electrode mixture layer 12 (such as a positive electrode active material and a binder) with a solvent. Positive electrode mixture layer 12 is in close contact with separator 30. The thickness of positive electrode mixture layer 12 is, for example, 0.1 μm or more and 1000 μm or less.

[0031] The positive electrode current collector 11 includes a positive electrode coated portion 11a and a positive electrode uncoated portion 11b. The positive electrode coated portion 11a is a portion of the positive electrode current collector 11 that is coated with a positive electrode composite layer 12. The positive electrode coated portion 11a is sandwiched between separators 30. The positive electrode coated portion 11a is an example of a "first coated portion" in the present disclosure. The positive electrode uncoated portion 11b is an example of a "first uncoated portion" in the present disclosure.

[0032] The positive electrode uncoated portion 11b is a portion of the positive electrode current collector 11 that is not coated with the positive electrode composite layer 12. The positive electrode uncoated portion 11b is located on the Z1 side of the positive electrode coated portion 11a. Specifically, the positive electrode uncoated portion 11b protrudes from the positive electrode coated portion 11a toward the Z1 side. The positive electrode uncoated portion 11b (portion 11d, described below) is provided at the end 1a on the Z1 side of the wound electrode body 1. The Z1 side is an example of "one side in the axial direction" in the present disclosure.

[0033] The positive electrode uncoated portion 11b includes a portion 11c extending along the Z direction and a portion 11d extending along the R direction. The positive electrode uncoated portion 11b is bent radially inward. The positive electrode uncoated portion 11b is bent into an L shape. The portion 11d of the positive electrode uncoated portion 11b is in contact with the positive electrode current collector plate 4. This causes the positive electrode current collector plate 4 to be positively charged. The positive electrode uncoated portion 11b (portion 11d) is joined to the positive electrode current collector plate 4 by welding. The portion 11d is an example of the "metal piece" and "axial intersection portion" of the present disclosure.

[0034] A plurality of portions 11d of the positive electrode uncoated portion 11b are arranged side by side along the winding direction of the wound electrode body 1. A slit 11e (see FIG. 5) is provided between adjacent portions 11d in the winding direction. Adjacent portions 11d in the R direction (radial direction) are arranged so as to partially overlap each other. Note that portions 11c of the positive electrode uncoated portion 11b are arranged so as to extend in the winding direction. In other words, each of the plurality of portions 11d is connected to one portion 11c.

[0035] As shown in FIG. 4, the negative electrode current collector 7 is housed in the case 2. The negative electrode current collector 7 is welded to a negative electrode uncoated portion 21b (described later) of the negative electrode plate 20 on the Z2 side of the wound electrode body 1. As a result, the negative electrode current collector 7 is negatively charged. The negative electrode current collector 7 is in contact with the case 2. As a result, the case 2 is negatively charged.

[0036] The negative electrode plate 20 includes a negative electrode current collector 21 and a negative electrode composite layer 22. The negative electrode composite layer 22 is applied to both radially opposite surfaces (R direction) of the negative electrode current collector 21 (a negative electrode coated portion 21a described below). The negative electrode composite layer 22 faces the separator 30 in the R direction. The negative electrode current collector 21 and the negative electrode composite layer 22 are examples of the "second current collector" and the "second electrode material layer" of the present disclosure, respectively.

[0037] Negative electrode current collector 21 is made of, for example, copper. Negative electrode mixture layer 22 is formed by applying a negative electrode slurry to the surface of negative electrode current collector 21 and drying the coating. The negative electrode slurry is prepared by kneading materials for negative electrode mixture layer 22 (negative electrode active material, binder, etc.) with a solvent. Negative electrode mixture layer 22 is in close contact with separator 30. The thickness of negative electrode mixture layer 22 is, for example, 0.1 μm or more and 1000 μm or less.

[0038] The negative electrode current collector 21 includes a negative electrode coated portion 21a and a negative electrode uncoated portion 21b. The negative electrode coated portion 21a is a portion of the negative electrode current collector 21 that is coated with a negative electrode composite layer 22. The negative electrode coated portion 21a is sandwiched between separators 30. The negative electrode coated portion 21a is an example of a "second coated portion" in the present disclosure. The negative electrode uncoated portion 21b is an example of a "second uncoated portion" in the present disclosure.

[0039] The negative electrode uncoated portion 21b is a portion of the negative electrode current collector 21 that is not coated with the negative electrode composite material layer 22. The negative electrode uncoated portion 21b is located on the Z2 side of the negative electrode coated portion 21a. Specifically, the negative electrode uncoated portion 21b protrudes from the negative electrode coated portion 21a toward the Z2 side. The negative electrode uncoated portion 21b is provided at the end 1b on the Z2 side of the wound electrode body 1. The Z2 side is an example of the "other axial side" in the present disclosure.

[0040] The negative electrode uncoated portion 21b includes a portion 21c extending along the Z direction and a portion 21d extending along the R direction. The negative electrode uncoated portion 21b is bent radially inward. The negative electrode uncoated portion 21b is bent into an L shape. The portion 21d of the negative electrode uncoated portion 21b is in contact with the negative electrode current collector plate 7. This causes the negative electrode current collector plate 7 to be negatively charged. The negative electrode uncoated portion 21b (portion 21d) is joined to the negative electrode current collector plate 7 by welding. The portion 21d is an example of a "metal piece" and an "axial intersection portion" of the present disclosure.

[0041] A plurality of portions 21d of the negative electrode uncoated portion 21b are arranged side by side along the winding direction of the wound electrode body 1. A slit 21e (see FIG. 6) is provided between the portions 21d adjacent to each other in the winding direction. The portions 21d adjacent to each other in the R direction are provided so as to partially overlap each other. The portions 21c of the negative electrode uncoated portion 21b are provided so as to extend in the winding direction. That is, each of the plurality of portions 21d is connected to one portion 21c.

[0042] In conventional energy storage cell configurations, the uncoated portions are provided to cover the axial ends of the wound electrode body, which can hinder the flow of electrolyte and make it difficult for the electrolyte to penetrate the separator.

[0043] Therefore, in the first embodiment, a through hole 11f is formed in each of the multiple portions 11d as shown in Fig. 3. Since the multiple portions 11d extend so as to intersect (substantially perpendicular to) the axial direction (Z direction), the axial direction of the through hole 11f is the penetration direction. Note that the through hole 11f is an example of an "opening" in the present disclosure.

[0044] A plurality of through holes 11f are provided in each of the plurality of portions 11d. At least some of the plurality of through holes 11f are provided at positions overlapping with the separator 30 in the Z direction. This allows the electrolyte solution that has flowed through the through holes 11f to efficiently flow to the separator 30. Note that the positions of the through holes 11f are not limited to the above example.

[0045] 4, a through-hole 21f is formed in each of the plurality of portions 21d. Since the plurality of portions 21d extend so as to intersect (substantially perpendicular to) the axial direction (Z direction), the axial direction of the through-hole 21f is the penetration direction. Note that the through-hole 21f is an example of an "opening" in the present disclosure.

[0046] A plurality of through holes 21f are provided in each of the plurality of portions 21d. At least some of the plurality of through holes 21f are provided at positions overlapping with the separator 30 in the Z direction. This allows the electrolyte solution that has flowed through the through holes 21f to flow efficiently to the separator 30.

[0047] 5 is a plan view of the positive electrode current collector 11 in an unwound state. As shown in FIG. 5, five through holes 11f are formed in each of the multiple portions 11d. The positive electrode uncoated portion 11b is not formed in the inner portion 11g of the wound positive electrode current collector 11 (for example, the portion corresponding to the innermost wound portion), but is provided on the outer periphery side of the inner portion 11g. The X direction shown in FIGS. 5 to 7 corresponds to the winding direction of the wound electrode body 1.

[0048] Fig. 6 is a plan view of the negative electrode current collector 21 in an unwound state. As shown in Fig. 6, five through holes 21f are formed in each of the multiple portions 21d. Note that the negative electrode uncoated portions 21b are not formed in the inner portion 21g of the winding (for example, the portion corresponding to the innermost winding) of the negative electrode current collector 21, but are provided on the outer peripheral side of the inner portion 21g.

[0049] Fig. 7 is a partially enlarged view of Fig. 5. As shown in Fig. 7, each of the plurality of through holes 11f has a circular shape. Specifically, the plurality of through holes 11f has a perfect circular shape with a diameter r. Note that the shape of the through holes 11f is not limited to the above example. Furthermore, the shape of the through hole 21f is the same as that of the through hole 11f, and therefore is not shown in the figure.

[0050] Furthermore, the slit 11e has a width W in the X direction. The diameter r of the through hole 11f is smaller than the width W of the slit 11e. Note that the diameter r may be equal to or larger than the width W. Furthermore, although detailed illustrations are omitted, the through hole 21f and the slit 21e have the same size (shape) as the through hole 11f and the slit 11e, respectively.

[0051] As described above, in the first embodiment, a through-hole 11f is formed in each of the multiple portions 11d of the positive electrode uncoated portion 11b. This allows the electrolyte to be introduced into the separator 30 through the through-hole 11f, even if the separator 30 is covered by the positive electrode uncoated portion 11b. As a result, even if excess electrolyte is squeezed out due to expansion of the wound electrode body 1 during charge and discharge, the electrolyte can be quickly returned to the wound electrode body 1. Furthermore, it is possible to prevent the resistance of the wound electrode body 1 from deteriorating due to a shortage of electrolyte inside the wound electrode body 1.

[0052] [Second embodiment] A second embodiment of the present disclosure will be described with reference to Figures 8 and 9. In the second embodiment, unlike the first embodiment in which through holes are formed in each of the positive electrode uncoated portion 11b and the negative electrode uncoated portion 21b, no through holes are formed in each of the positive electrode uncoated portion and the negative electrode uncoated portion. The same components as in the first embodiment are denoted by the same reference numerals and will not be described repeatedly.

[0053] 8, the energy storage cell 200 differs from the energy storage cell 100 of the first embodiment in that it includes a wound electrode body 31 instead of the wound electrode body 1. The wound electrode body 31 is housed in a case 2.

[0054] The wound electrode body 31 includes a positive electrode plate 110, a negative electrode plate 120, and a separator 30. The separator 30 is provided between the positive electrode plate 110 and the negative electrode plate 120. The positive electrode plate 110 and the negative electrode plate 120 are examples of the "first electrode" and the "second electrode" of the present disclosure, respectively.

[0055] The wound electrode body 31 is formed by winding a positive electrode plate 110, a negative electrode plate 120, and a separator 30 around a winding axis β.

[0056] The positive electrode plate 110 includes a positive electrode current collector 111 and a positive electrode composite layer 12. The positive electrode current collector 111 includes a positive electrode coated portion 11a and a positive electrode uncoated portion 111b. The positive electrode uncoated portion 111b (portion 111d described below) is provided at the end portion 31a on the Z1 side of the wound electrode body 31.

[0057] The positive electrode uncoated portion 111b includes a portion 11c extending along the Z direction and a portion 111d extending along the R direction. The positive electrode uncoated portion 111b is bent radially inward. The positive electrode uncoated portion 111b is bent in an L-shape. The portion 111d is an example of the "metal piece" and "radial portion" of the present disclosure.

[0058] A plurality of portions 111d of the positive electrode uncoated portion 111b are arranged side by side along the winding direction of the wound electrode body 31. That is, each of the plurality of portions 111d is connected to one portion 11c extending in the winding direction.

[0059] In the second embodiment, some of the multiple portions 111d have a smaller length in the radial direction (the direction in which the portions 111d extend in FIG. 8) than the remaining portions of the multiple portions 111d. The length L1 of the portions 111d is smaller than the length L2 of the remaining portions 111d. As a result, a gap S1 is formed between the portions 111d of length L1 and the portions 111d of length L2, which are arranged side by side in the radial direction. The gap S1 (opening) may be formed at a position overlapping with the separator 30 in the axial direction (Z direction). The direction in which the portions 111d extend in FIG. 8 is an example of the "predetermined direction" in the present disclosure.

[0060] The positional relationship between the portion 111d of length L1 and the portion 111d of length L2 is not limited to the example shown in Fig. 8. For example, the portion 111d of length L1 may be disposed at a position closest to the winding axis β among the multiple portions 111d.

[0061] 9, the negative electrode plate 120 includes a negative electrode current collector 121 and a negative electrode composite layer 22. The negative electrode current collector 121 includes a negative electrode coated portion 21a and a negative electrode uncoated portion 121b. The negative electrode uncoated portion 121b (portion 121d described below) is provided at the end 31b on the Z2 side of the wound electrode body 31.

[0062] The negative electrode uncoated portion 121b includes a portion 21c extending along the Z direction and a portion 121d extending along the R direction. The negative electrode uncoated portion 121b is bent radially inward. The negative electrode uncoated portion 121b is bent in an L-shape. The portion 121d is an example of the "metal piece" and "radial portion" of the present disclosure.

[0063] A plurality of portions 121d of negative electrode uncoated portion 121b are arranged side by side along the winding direction, that is, each of the plurality of portions 121d is connected to one portion 21c extending in the winding direction.

[0064] In the second embodiment, some of the multiple portions 121d have a shorter length in the radial direction (the direction in which the portions 121d extend in FIG. 9) than the remaining portions of the multiple portions 121d. The length L11 of the portions 121d is shorter than the length L12 of the remaining portions 121d. As a result, a gap S2 (opening) is formed between the portions 121d of length L11 and the portions 121d of length L12, which are arranged side by side in the radial direction. The gap S2 may be formed at a position overlapping the separator 30 in the axial direction (Z direction). The direction in which the portions 121d extend in FIG. 9 is an example of the "predetermined direction" in the present disclosure.

[0065] The positional relationship between the portion 121d of length L11 and the portion 121d of length L12 is not limited to the example shown in Fig. 9. For example, the portion 121d of length L11 may be disposed at a position closest to the winding axis β among the multiple portions 121d.

[0066] As described above, in the second embodiment, some of the plurality of portions 111d (121d) have a length in the extension direction of the portions 111d (121d) that is shorter than the remaining portion of the plurality of portions 111d (121d). As a result, when the portions 111d (121d) having different lengths are aligned in the radial direction, gaps S1 (S2) are formed between the portions 111d (121d). This allows the electrolyte to flow through the gaps S1 (S2) toward the separator 30.

[0067] In the first embodiment, an example in which a plurality of through holes 11f (21f) are provided in the portion 11d (21d) has been described, but the present disclosure is not limited to this. Only one through hole 11f (21f) may be provided in the portion 11d (21d).

[0068] In the first embodiment, an example was shown in which the through-hole 11f (21f) is provided in each of the multiple portions 11d (21d), but the present disclosure is not limited to this. The through-hole 11f (21f) may be provided in some of the multiple portions 11d (21d). For example, the through-hole 11f (21f) may be provided in only one portion 11d (21d).

[0069] In the first embodiment, an example in which the through-hole 11f (21f) is provided in the portion 11d (21d) is shown, but the present disclosure is not limited to this. A through-hole may be provided in the portion 11c (21c). Also, a through-hole may be provided in each of the portion 11d (21d) and the portion 11c (21c).

[0070] In the first embodiment, an example in which the through hole 11f (21f) is provided in the portion 11d (21d) has been described, but the present disclosure is not limited to this. An opening other than a through hole may be provided. In the example shown in FIG. 10, a notch 211a is provided in the portion 211d. The notch 211a is provided at the end 211b (the radially inner end) of the portion 211d. A plurality of the notches 211a (two in FIG. 10) are provided side by side in the winding direction (the X direction in FIG. 10). The same may be true for the negative electrode side. Both a through hole and a notch may be formed. The portion 211d is an example of an "axial portion" and a "metal piece" in the present disclosure. The notch 211a is an example of an "opening" in the present disclosure.

[0071] In the first embodiment, an example in which multiple portions 11d are connected to a single portion 11c extending in the axial direction is shown, but the present disclosure is not limited to this. As shown in FIG. 11, each of the multiple portions 11d may be connected to a portion 111c (corresponding to portion 11c) extending in the axial direction. In the example shown in FIG. 11, a slit 111e is formed between multiple metal pieces formed by portion 11c and portion 11d. Note that a similar configuration may also be used on the negative electrode side.

[0072] In the first embodiment, an example was shown in which through-holes were formed in both the positive electrode uncoated portion 11b and the negative electrode uncoated portion 21b, but the present disclosure is not limited to this. Through-holes may be formed in only one of the positive electrode uncoated portion 11b and the negative electrode uncoated portion 21b.

[0073] In the second embodiment, the length of some of the positive electrode side portions 111d and the negative electrode side portions 121d are shorter than the length of the remaining portions, but the present disclosure is not limited to this. The length of only one of the positive electrode side portions 111d and the negative electrode side portions 121d may be shorter than the length of the remaining portions.

[0074] In the first (second) embodiment, the positive electrode uncoated portion 11b (111b) and the negative electrode uncoated portion 21b (121b) are each bent radially inward, but the present disclosure is not limited to this. At least one of the positive electrode uncoated portion 11b (111b) and the negative electrode uncoated portion 21b (121b) may be bent radially outward.

[0075] The configurations of the above-described embodiment and the above-described modifications may be combined with each other.

[0076] The embodiments disclosed herein should be considered to be illustrative in all respects and not restrictive. The scope of the present disclosure is defined by the claims, not by the description of the above embodiments, and is intended to include all modifications within the meaning and scope of the claims. [Explanation of symbols]

[0077] 1, 31 Wound electrode body, 1a, 1b, 31a, 31b End, 2 Case, 10, 110 Positive electrode plate (first electrode), 11 Positive electrode current collector (first current collector), 11a Positive electrode coated portion (first coated portion), 11b Positive electrode uncoated portion (first uncoated portion), 11d, 21d, 211d Portion (metal piece) (axial intersection portion), 11f, 21f Through hole (opening), 12 Positive electrode composite layer (first electrode material layer), 20, 120 Negative electrode plate (second electrode), 21 Negative electrode current collector (second current collector), 21a Negative electrode coated portion (second coated portion), 21b Negative electrode uncoated portion (second uncoated portion), 22 Negative electrode composite layer (second electrode material layer), 30 Separator, 100, 200 Energy storage cell, 111d, 121d part (metal piece) (radial part), 211a notch (opening), L1, L2, L11, L12 length, R direction (radial direction), Z direction (axial direction), α, β winding axis.

Claims

1. a wound electrode body including a first electrode, a second electrode, and a separator disposed between the first electrode and the second electrode; a case that houses the wound electrode body, the wound electrode body is formed by winding the first electrode, the second electrode, and the separator around a winding axis, At least one of the first electrode and the second electrode includes a plurality of metal pieces provided at an end of the wound electrode body in an axial direction in which the winding axis extends, each of the plurality of metal pieces includes a radial portion extending in a predetermined direction along the radial direction of the wound electrode body; A storage cell, wherein some of the radial portions of the plurality of metal pieces have a length in the predetermined direction that is smaller than that of the remaining radial portions of the plurality of metal pieces.

2. a wound electrode body including a first electrode, a second electrode, and a separator disposed between the first electrode and the second electrode; a case that houses the wound electrode body, the wound electrode body is formed by winding the first electrode, the second electrode, and the separator around a winding axis, At least one of the first electrode and the second electrode includes a plurality of metal pieces provided at an end of the wound electrode body in an axial direction in which the winding axis extends, each of the plurality of metal pieces includes a radial portion extending in a predetermined direction along the radial direction of the wound electrode body; At least one notch is formed in the radial portion of at least one of the plurality of metal pieces, The at least one notch is formed at an end of the radial portion on an open side in the predetermined direction.

3. a wound electrode body including a first electrode, a second electrode, and a separator disposed between the first electrode and the second electrode; a case that houses the wound electrode body, the wound electrode body is formed by winding the first electrode, the second electrode, and the separator around a winding axis, At least one of the first electrode and the second electrode includes a plurality of metal pieces provided at an end of the wound electrode body in an axial direction in which the winding axis extends, each of the plurality of metal pieces includes a radial portion extending in a predetermined direction along the radial direction of the wound electrode body; At least one opening is formed in the radial portion of at least one of the plurality of metal pieces, The at least one opening is formed in the center of the radial portion when the radial portion is viewed from a position spaced apart from the wound electrode body in the axial direction.

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