Power storage cell

Abstract

To provide a power storage cell capable of increasing permeation of an electrolyte solution into a wound electrode body.SOLUTION: A power storage cell 10 includes a wound electrode body 100 including a positive electrode and a negative electrode that are wound, a housing 200 that accommodates the wound electrode body 100 and an electrolyte solution internally, and a sealing part 250. The housing 200 includes an outer tubular part 210 disposed on the outside in a radial direction of the wound electrode body 100, and an inner tubular part 240 penetrating a hollow part of the wound electrode body 100 in an axial direction of the wound electrode body 100. The wound electrode body 100 and the electrolyte solution are disposed between the outer tubular part 210 and the inner tubular part 240. The inner tubular part 240 includes a plurality of hole parts 241h. The sealing part 250 includes a part disposed inside the inner tubular part 240 so as to seal the hole parts 241h.SELECTED DRAWING: Figure 1

Description

[Technical field]

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

[0002] Japanese Patent Laid-Open Publication No. 2001-093566 (Patent Document 1) discloses a cylindrical battery characterized in that the core material of the cylindrical battery is made of a hollow material, and air can pass through the hollow part of this hollow material. Patent Document 1 states that the above configuration can promote the heat dissipation effect and prevent the performance deterioration of the cylindrical battery. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2001-093566 A Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the configuration of Patent Document 1, sufficient consideration is not given to the permeation of the electrolyte, and there is concern that it may be difficult to make the electrolyte permeate the electrode assembly evenly.

[0005] The present disclosure has been made in consideration of the above-mentioned problems, and an object of the present disclosure is to provide an electricity storage cell that is capable of increasing the permeability of an electrolyte into a wound electrode body. [Means for solving the problem]

[0006] The energy storage cell according to the present embodiment includes a wound electrode body including wound positive and negative electrodes, a housing that accommodates the wound electrode body and an electrolyte, and a sealing portion. The housing includes an outer tube portion disposed radially outside the wound electrode body, and an inner tube portion that penetrates a hollow portion of the wound electrode body in the axial direction of the wound electrode body. The wound electrode body and the electrolyte are disposed between the outer tube portion and the inner tube portion. A plurality of holes are provided in the inner tube portion. The sealing portion includes a portion disposed inside the inner tube portion so as to seal the plurality of holes.

[0007] In the storage cell based on the above embodiment, the sealing portion may have a first portion arranged inside the inner cylindrical portion at one end side of the inner cylindrical portion in a direction parallel to the axial direction, and a second portion extending inside the inner cylindrical portion along a direction parallel to the axial direction so as to seal the multiple holes.

[0008] In the energy storage cell according to the present embodiment, the housing may include a first end face located at one end side in a direction parallel to the axial direction and a second end face located at the other end side in a direction parallel to the axial direction, and the second portion may have an abutment portion abutting against the second end face. Effect of the Invention

[0009] According to the present disclosure, it is possible to provide an electricity storage cell capable of increasing the permeability of an electrolyte into a wound electrode body. [Brief description of the drawings]

[0010] [Figure 1] 1 is a cross-sectional view of a storage cell according to an embodiment. [Diagram 2] 5A and 5B are diagrams showing a state in which an electrolyte solution is injected into the electricity storage cell according to the embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. In the embodiments described below, the same or common parts are denoted by the same reference characters in the drawings, and the description thereof will not be repeated.

[0012] Fig. 1 is a cross-sectional view of a storage cell according to an embodiment. A storage cell 10 according to the embodiment will be described with reference to Fig. 1. The storage cell 10 is, for example, a lithium ion battery mounted on a vehicle. Note that the use and type of the storage cell are not limited to the above examples.

[0013] 1, the energy storage cell 10 is a cylindrical battery, more specifically, a cylindrical battery. The energy storage cell 10 includes a wound electrode body 100, a housing 200, and a sealing portion 250.

[0014] The wound electrode body 100 includes a positive electrode plate 110 as a positive electrode, a negative electrode plate 120 as a negative electrode, a separator 130, a positive electrode tab lead 140, and a negative electrode tab lead 150. The positive electrode plate 110 and the negative electrode plate 120 are wound around a winding axis parallel to the axial direction Z with the separator 130 interposed therebetween.

[0015] The separator 130 is provided between the positive electrode plate 110 and the negative electrode plate 120. The separator 130 separates the positive electrode plate 110 from the negative electrode plate 120 while allowing ions (e.g., lithium ions) to move between the positive electrode plate 110 (positive electrode active material) and the negative electrode plate 120 (negative electrode active material).

[0016] The positive electrode plate 110 includes a positive electrode current collector and a positive electrode composite layer. The positive electrode composite layer is applied to a portion of the positive electrode current collector. That is, the positive electrode current collector includes a coated portion to which the positive electrode composite layer is applied and an uncoated portion to which the positive electrode composite layer is not applied.

[0017] The positive electrode current collector is made of, for example, aluminum. The positive electrode mixture layer is formed by applying a positive electrode slurry to the surface of the positive electrode current collector and drying it. The positive electrode slurry is prepared by kneading the materials for the positive electrode mixture layer (such as a positive electrode active material and a binder) with a solvent. The positive electrode mixture layer is in close contact with the separator 130. The thickness of the positive electrode mixture layer is, for example, 0.1 μm or more and 1000 μm or less.

[0018] The negative electrode plate 120 includes a negative electrode current collector and a negative electrode composite layer. The negative electrode composite layer is applied to a portion of the negative electrode current collector. That is, the negative electrode current collector includes a coated portion to which the negative electrode composite layer is applied and an uncoated portion to which the negative electrode composite layer is not applied.

[0019] The negative electrode current collector is made of, for example, copper foil. The negative electrode mixture layer is formed by applying a negative electrode slurry to the surface of the negative electrode current collector and drying it. The negative electrode slurry is a slurry prepared by kneading the materials of the negative electrode mixture layer (negative electrode active material, binder, etc.) with a solvent. The negative electrode mixture layer is in close contact with the separator 130. The thickness of the negative electrode mixture layer is, for example, 0.1 μm or more and 1000 μm or less.

[0020] The negative electrode tab lead 150 is provided so as to protrude from the negative electrode current collector of the negative electrode plate 120 to one side in the axial direction Z (the Z1 side).

[0021] The positive electrode tab lead 140 is provided so as to protrude from the positive electrode current collector of the positive electrode plate 110 to the other side in the axial direction Z (the Z2 side).

[0022] The housing 200 accommodates the wound electrode body 100 and the electrolyte inside. The housing 200 has a substantially cylindrical shape, and a sealing portion 250, which will be described later, is disposed in the hollow portion of the housing 200.

[0023] The housing 200 includes an outer cylindrical portion 210 , a first end 230 , a second end 220 , and an inner cylindrical portion 240 .

[0024] The outer cylinder portion 210 is cylindrical and extends along the axial direction Z. The outer cylinder portion 210 constitutes an outer peripheral wall portion of the housing 200. The outer cylinder portion 210 is disposed on the radially outer side of the wound electrode body 100 in the radial direction R. The outer cylinder portion 210 is formed of copper, aluminum, or the like. The outer cylinder portion 210 is in contact with a current collector of the negative electrode plate 120 disposed on the outermost periphery of the wound electrode body 100.

[0025] The first end 230 is located on one side in a direction parallel to the axial direction Z. The first end 230 covers the wound electrode body 100 from one side in the axial direction Z. The first end 230 has a disk shape. A through hole (first through hole) 231 that penetrates in a direction parallel to the axial direction Z is provided in the center of the first end 230.

[0026] The first end portion 230 has an outer surface 230a. The outer surface 230a constitutes a first end face of the housing 200. The outer surface 230a is located on one end side of the housing 200 in a direction parallel to the axial direction Z.

[0027] The periphery of the first end portion 230 is connected to the outer tubular portion 210. The first end portion 230 is integrally formed with the outer tubular portion 210. The first end portion 230 is formed from copper, aluminum, or the like.

[0028] The first end 230 is in contact with the negative electrode tab lead 150. This electrically connects the negative electrode tab lead 150 and the first end 230. As a result, the first end 230 and the outer cylinder portion 210, as well as a crimped portion 224 described later, are negatively charged.

[0029] The second end 220 is located on the other side in the direction parallel to the axial direction Z. The second end 220 covers the wound electrode body 100 from the other side in the axial direction Z. The second end 220 is provided with a through hole (second through hole) 221 that penetrates in a direction parallel to the axial direction Z. The second end 220 has an outer surface 220a. The outer surface 220a forms a second end face of the housing 200. The outer surface 220a is located on the other end side of the housing 200 in the direction parallel to the axial direction Z.

[0030] The second end 220 includes an outer cap 222 , an insulating layer 223 , and a crimping portion 224 .

[0031] The external cap 222 functions as an external terminal. A bus bar is electrically connected to the external cap 222. The external cap 222 is provided with a weak portion 225 (thin portion).

[0032] External cap 222 is easily broken from weak portion 225 when the internal pressure of housing 200 increases. This allows gas to be quickly discharged to the outside of housing 200. Through hole 221 is provided in external cap 222. External cap 222 is made of copper, aluminum, or the like.

[0033] The insulating layer 223 is disposed so as to cover the outer peripheral edge of the outer cap 222. The insulating layer 223 is provided so as to insulate the outer cap 222 from the crimping portion 224.

[0034] The crimping portion 224 is connected to an end of the outer tube portion 210 located on the opposite side to the side on which the first end portion 230 is located in a direction parallel to the axial direction Z. The crimping portion 224 is molded integrally with the outer tube portion 210. The crimping portion 224 crimps the outer periphery of the outer cap 222 (and the conductive film 510 described later) via the insulating layer 223. The crimping portion 224 is formed of copper, aluminum, or the like.

[0035] The inner cylinder portion 240 extends along the axial direction Z from the through hole 231 toward the through hole 221. The inner cylinder portion 240 penetrates the hollow portion of the wound electrode body 100 in the axial direction Z. The inner cylinder portion 240 is disposed on the inside of the wound electrode body 100 in the radial direction R. In other words, the wound electrode body 100 (and the electrolyte) is disposed between the outer cylinder portion 210 and the inner cylinder portion 240.

[0036] The inner cylinder portion 240 has a core portion 241, a first insulating end portion 243, and a second insulating end portion 242. The inner cylinder portion 240 is provided with a plurality of holes 241h.

[0037] The core 241 is made of a hollow core material and constitutes most of the inner cylinder 240. The core 241 is disposed on the inside in the radial direction R of the wound electrode body 100. The core 241 may be used as a core material when the electrode plate group is wound to form the wound electrode body 100. The core 241 may be made of a metal such as copper or aluminum.

[0038] The core 241 is provided with a plurality of holes 241h penetrating in the radial direction. The plurality of holes 241h are provided at intervals in the circumferential direction and in a direction parallel to the axial direction Z. The plurality of holes 241h function as injection ports when injecting an electrolyte solution.

[0039] The first insulating end 243 is located on one side (Z1 side) of the core 241 in a direction parallel to the axial direction Z. The first insulating end 243 insulates the core 241 from the first end 230. The core 241 is fixed to the first end 230 via the first insulating end 243. Specifically, a fitting portion that fits into the first insulating end 243 is provided around the through hole 231 in the first end 230, and the core 241 is fixed to the first end 230 by fitting the first insulating end 243 into the fitting portion.

[0040] The second insulating end 242 is disposed on the other side (Z2 side) of the core 241 in a direction parallel to the axial direction Z. The second insulating end 242 insulates the core 241 from the second end 220. The core 241 is fixed to the second end 220 via the second insulating end 242. Specifically, a fitting portion that fits into the second insulating end 242 is provided around the through hole 221 in the second end 220, and the fitting portion is fitted into the second insulating end 242, whereby the core 241 is fixed to the second end 220.

[0041] The sealing portion 250 is for sealing the multiple holes 241h. The sealing portion 250 includes a first portion 251 and a second portion 252.

[0042] The first portion 251 is disposed inside the inner cylinder portion 240 on one end side of the inner cylinder portion 240 in a direction parallel to the axial direction Z. The first portion 251 is disposed closer to the first end portion 230 than the hole portion 241h that is located furthest on one side in a direction parallel to the axial direction Z among the plurality of holes 241h. The first portion 251 seals, for example, from the through hole 231 to the hole portion 241h that is located furthest on one side in a direction parallel to the axial direction Z among the plurality of holes 241h inside the inner cylinder portion 240.

[0043] The second portion 252 includes an extension portion that extends inside the inner cylinder portion 240 from the first portion 251 to the through hole 221 in a direction parallel to the axial direction Z, and an abutment portion 253. The extension portion is disposed inside the inner cylinder portion 240 so as to seal the multiple holes 241h. The outer surface of the extension portion is in close contact with the inner surface of the core portion 241, thereby sealing the multiple holes 241h. As a result, it is possible to suppress leakage of the electrolyte from inside the housing 200 through the inside of the inner cylinder portion 240 to the outside. The abutment portion 253 abuts against the outer surface 220a of the second end portion 220 from the outside of the housing 200. The outer shape of the abutment portion 253 is larger than the outer shape of the through hole 221.

[0044] The energy storage cell 10 further includes a positive insulating plate 300, a negative insulating plate 400, and a current interrupt device 500.

[0045] The negative insulating plate 400 is accommodated in the housing 200. The negative insulating plate 400 is provided so as to insulate the wound electrode body 100 (more specifically, the positive electrode plate 110 and the separator 130) from the housing 200. The negative insulating plate 400 is provided so as to cover the positive electrode plate 110, the negative electrode plate 120, and the separator 130 from the one side (Z1 side).

[0046] The negative insulating plate 400 has a through hole 410. The negative tab lead 150 is inserted into the through hole 410. This electrically connects the negative tab lead 150 and the first end 230. The inner cylinder portion 240 (more specifically, the core portion 241 and the first insulating end 243) is also inserted into the through hole 410.

[0047] The positive-side insulating plate 300 is accommodated in the housing 200. The positive-side insulating plate 300 is provided so as to insulate the wound electrode body 100 (more specifically, the negative electrode plate 120 and the separator 130) from the housing 200. The positive-side insulating plate 300 is provided so as to cover the positive electrode plate 110, the negative electrode plate 120, and the separator 130 from the other side (Z2 side).

[0048] The positive-side insulating plate 300 has a first through hole 310 and a second through hole 320. The positive electrode tab lead 140 is inserted through the first through hole 310, and is thereby in contact with a conductive film 510, which will be described later. This electrically connects the positive electrode tab lead 140 and the conductive film 510. The inner cylinder portion 240 (core portion 241) is inserted through the second through hole 320.

[0049] The current interruption device 500 is an element that interrupts a current path by utilizing an increase in cell internal pressure caused by gas generated due to overcharging of the energy storage cell 10. The current interruption device 500 is provided so as to seal the opening on the other side (Z2 side) of the outer tubular portion 210. The current interruption device 500 has a conductive film 510, a gasket 520, and a bottom disk 530.

[0050] The conductive film 510 is provided so as to seal the opening on the other side (Z2 side) of the outer cylinder portion 210. The conductive film 510 is in contact with the positive electrode tab lead 140. As a result, the conductive film 510 is positively charged. The conductive film 510 is also electrically connected to the external cap 222 by a connection member (not shown). As a result, the external cap 222 is also positively charged.

[0051] The conductive film 510 has a weak portion 511 (thin portion) similar to the external cap 222. When the internal pressure of the housing 200 increases, the conductive film 510 is easily broken from the weak portion 511. When the conductive film 510 breaks due to the increase in internal pressure, the contact between the conductive film 510 and the positive electrode tab lead 140 is released. This causes the positive charge of the conductive film 510 to be released, and also the positive charge of the external cap 222 to be released. As a result, charging and discharging of the energy storage cell 10 is stopped.

[0052] The gasket 520 is located on the wound electrode body 100 side of the conductive film 510. The bottom disk 530 is connected to the conductive film 510 via the gasket 520.

[0053] Of the inner tube portion 240, the core portion 241 and the second insulating end portion 242 penetrate the current interruption device 500. Specifically, the core portion 241 and the second insulating end portion 242 penetrate the conductive film 510, the gasket 520, and the bottom disk 530.

[0054] 2 is a diagram showing a state in which an electrolyte solution is injected into a power storage cell according to an embodiment. As shown in FIG. 2, when injecting an electrolyte solution, for example, the space inside the inner cylinder portion 240 is used. Specifically, in a state in which the second portion 252 of the sealing portion 250 is not disposed inside the inner cylinder portion 240, but the first portion 251 is disposed, the electrolyte solution is injected into the inner space of the inner cylinder portion 240 from the through hole 221. By disposing the first portion 251, it is possible to prevent the electrolyte solution from leaking from the through hole 231.

[0055] The electrolyte injected into the inner space of the inner cylinder portion 240 passes through each of the multiple holes 241h and permeates the inside of the wound electrode body 100 from the inside to the outside of the wound electrode body 100, as shown by arrow AR1. This can increase the permeability of the electrolyte into the wound electrode body 100. Note that, in addition to the above, the electrolyte may be injected into the housing 200 through an injection port provided in the housing 200.

[0056] Next, after injecting the electrolyte, the second part 252 is inserted into the inner cylinder part 240 so that the abutting part 253 abuts against the outer surface 220a. As a result, the electrolyte located inside the inner cylinder part 240 is pushed by the second part 252 and moves into the housing 200 through the multiple holes 241h. In addition, the multiple holes 241h are sealed by the second part 252. By stopping the insertion of the second part 252 with the abutting part 253 abutting against the outer surface 220a as described above, it is possible to prevent the first part 251 from being excessively pushed by the second part 252 and coming off from the inside of the inner cylinder part 240, or the second part 252 and the second end part 220 from being deformed due to an excessive load being applied to them.

[0057] The embodiments disclosed herein are illustrative and not restrictive in all respects. The scope of the present invention is defined by the claims, and includes all modifications within the meaning and scope of the claims. [Explanation of symbols]

[0058] 10 storage cell, 100 wound electrode body, 110 positive electrode plate, 120 negative electrode plate, 130 separator, 140 positive electrode tab lead, 150 negative electrode tab lead, 200 housing, 210 outer cylinder portion, 220 second end portion, 220a outer surface, 221 through hole, 222 outer cap, 223 insulating layer, 224 crimping portion, 225 weak portion, 230 first end portion, 230a outer surface, 231 through hole, 240 inner cylinder portion, 241 core portion, 242 second insulating end portion, 243 first insulating end portion, 250 sealing portion, 251 first portion, 241h hole portion, 252 second portion, 253 abutment portion, 300 positive side insulating plate, 310 first through hole, 320 second through hole, 400 Negative insulating plate, 410 through hole, 500 current interrupter, 510 conductive film, 511 frangible portion, 520 gasket, 530 bottom disk.

Claims

1. A wound electrode body including wound positive and negative electrodes; a housing that contains the wound electrode body and an electrolyte; A sealing portion, The housing includes an outer cylinder portion disposed radially outside the wound electrode body, and an inner cylinder portion penetrating a hollow portion of the wound electrode body in an axial direction of the wound electrode body, the wound electrode body and the electrolyte are disposed between the outer cylinder portion and the inner cylinder portion, The inner cylinder portion is provided with a plurality of holes, The sealing portion includes a portion disposed inside the inner cylinder portion so as to seal the plurality of holes.

2. 2. The energy storage cell according to claim 1, wherein the sealing portion has a first portion arranged inside the inner cylindrical portion at one end side of the inner cylindrical portion in a direction parallel to the axial direction, and a second portion extending inside the inner cylindrical portion along a direction parallel to the axial direction so as to seal the multiple holes.

3. the housing includes a first end surface located on one end side in a direction parallel to the axial direction and a second end surface located on the other end side in the direction parallel to the axial direction, The energy storage cell according to claim 2 , wherein the second portion has an abutment portion that abuts against the second end surface from an outside of the housing.

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