Energy 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] This disclosure relates to a storage battery cell.

Background Art

[0002] Japanese Patent Application Laid-Open No. 2001-093566 (Patent Document 1) discloses a cylindrical battery characterized in that the core material of the cylindrical battery is a hollow material, and air can pass through the hollow portion of the hollow material. Patent Document 1 describes that with the above configuration, the heat dissipation effect can be promoted and the deterioration of the performance of the cylindrical battery can be prevented.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in the configuration of Patent Document 1, the penetration of the electrolytic solution is not sufficiently considered, and there is a concern that it may be difficult to uniformly penetrate the electrolytic solution into the electrode body.

[0005] This disclosure has been made in view of the above problems, and an object of this disclosure is to provide a storage battery cell capable of enhancing the permeability of the electrolytic solution to the wound electrode body.

Means for Solving the Problems

[0006] The energy storage cell according to this embodiment comprises a wound electrode body including a wound positive electrode and a wound negative electrode, a housing that houses the wound electrode body and an electrolyte, and a sealing portion. The housing includes an outer cylindrical portion positioned radially outward from the wound electrode body and an inner cylindrical portion that penetrates the hollow portion of the wound electrode body in the axial direction. The wound electrode body and the electrolyte are arranged between the outer cylindrical portion and the inner cylindrical portion. The inner cylindrical portion is provided with a plurality of holes. The sealing portion includes a portion positioned inside the inner cylindrical portion to seal the plurality of holes.

[0007] In the energy storage cell according to the above embodiment, the sealing portion may have a first portion located inside the inner cylinder portion at one end of the inner cylinder portion in a direction parallel to the axial direction, and a second portion extending inside the inner cylinder portion in a direction parallel to the axial direction so as to seal the plurality of holes.

[0008] In the energy storage cell according to the above embodiment, the housing may include a first end face located at one end in a direction parallel to the axial direction, and a second end face located at the other end in a direction parallel to the axial direction. The second portion may have a contact portion that abuts against the second end face. [Effects of the Invention]

[0009] According to this disclosure, it is possible to provide an energy storage cell that can improve the permeability of the electrolyte to the wound electrode body. [Brief explanation of the drawing]

[0010] [Figure 1] This is a cross-sectional view of an energy storage cell according to an embodiment. [Figure 2] This figure shows the process of injecting electrolyte into a storage cell according to an embodiment. [Modes for carrying out the invention]

[0011] The embodiments of this disclosure will be described in detail below with reference to the drawings. In the embodiments described below, the same or common parts are denoted by the same reference numerals in the drawings, and their descriptions will not be repeated.

[0012] Figure 1 is a cross-sectional view of a storage cell according to an embodiment. Referring to Figure 1, the storage cell 10 according to the embodiment will be described. The storage cell 10 is, for example, a lithium-ion battery installed in a vehicle. Note that the applications and types of storage cells are not limited to the above example.

[0013] As shown in Figure 1, the energy storage cell 10 is a cylindrical battery, more specifically a cylindrical battery. The energy storage cell 10 comprises 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 the positive electrode, a negative electrode plate 120 as the 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 between them.

[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 (positive electrode active material) and the negative electrode plate 120 (negative electrode active material) while allowing ions (for example, lithium ions) to move between them.

[0016] The positive electrode plate 110 includes a positive electrode current collector and a positive electrode composite layer. The positive electrode composite layer is coated onto 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] For the positive electrode current collector, for example, aluminum or the like is used. The positive electrode composite 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 a slurry prepared by kneading the materials of the positive electrode composite layer (positive electrode active material, binder, etc.) and a solvent. The positive electrode composite layer is in close contact with the separator 130. The thickness of the positive electrode composite 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 part of the negative electrode current collector. That is, the negative electrode current collector includes a coated portion where the negative electrode composite layer is applied and an uncoated portion where the negative electrode composite layer is not applied.

[0019] For the negative electrode current collector, for example, a copper foil or the like is used. The negative electrode composite 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 composite layer (negative electrode active material and binder, etc.) and a solvent. The negative electrode composite layer is in close contact with the separator 130. The thickness of the negative electrode composite 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 project from the negative electrode current collector of the negative electrode plate 120 to one side (Z1 side) in the axial direction Z.

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

[0022] The housing 200 houses the wound electrode body 100 and the electrolytic solution inside. The housing 200 has a substantially cylindrical shape, and a sealing portion 250 described later is arranged in the hollow portion of the housing 200.

[0023] The housing 200 includes an outer cylindrical portion 210, a first end portion 230, a second end portion 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 the outer peripheral wall of the housing 200. The outer cylinder portion 210 is positioned radially R outward of the wound electrode body 100. The outer cylinder portion 210 is made of copper or aluminum, or the like. The outer cylinder portion 210 is in contact with the current collector of the negative electrode plate 120, which is positioned on the outermost periphery of the wound electrode body 100.

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

[0026] The first end portion 230 has an outer surface 230a. This outer surface 230a constitutes the 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 first end portion 230 has a periphery connected to the outer cylinder portion 210. The first end portion 230 is integrally molded with the outer cylinder portion 210. The first end portion 230 is made of copper or aluminum, or the like.

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

[0029] The second end portion 220 is located on the other side in a direction parallel to the axial direction Z. The second end portion 220 covers the wound electrode body 100 from the other side in the axial direction Z. The second end portion 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 portion 220 has an outer surface 220a. This outer surface 220a constitutes the second end face of the housing 200. The outer surface 220a is located on the other end side of the housing 200 in a direction parallel to the axial direction Z.

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

[0031] The external cap 222 functions as an external terminal. A busbar is electrically connected to the external cap 222. The external cap 222 is provided with a fragile portion 225 (thin-walled portion).

[0032] The outer cap 222 is designed to break easily, starting from a weak point 225, when the internal pressure of the housing 200 increases. This allows gas to be quickly released to the outside of the housing 200. A through hole 221 is provided in the outer cap 222. The outer cap 222 is made of copper or aluminum, among other materials.

[0033] The insulating layer 223 is positioned to cover the outer edge of the outer cap 222. The insulating layer 223 is provided to insulate the outer cap 222 from the crimped portion 224.

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

[0035] The inner cylinder portion 240 extends axially Z from the through hole 231 to 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 located radially R inside the wound electrode body 100. In other words, the wound electrode body 100 (and electrolyte) is located 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 also provided with a plurality of holes 241h.

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

[0038] The core portion 241 is provided with a plurality of holes 241h that penetrate radially. The plurality of holes 241h are spaced apart in the circumferential direction and in a direction parallel to the axial direction Z. These plurality of holes 241h function as inlet ports when injecting electrolyte.

[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 is provided around the through hole 231 of the first end 230 that fits into the first insulating end 243, and the core 241 is fixed to the first end 230 by fitting the first insulating end 243 into this fitting portion.

[0040] The second insulating end 242 is positioned 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 is provided around the through hole 221 of the second end 220 that fits into the second insulating end 242, and the core 241 is fixed to the second end 220 when this fitting portion is fitted into the second insulating end 242.

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

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

[0043] The second portion 252 includes an extended portion that extends along the inside of 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 a contact portion 253. The extended portion is positioned inside the inner cylinder portion 240 to seal the multiple holes 241h. The outer surface of the extended portion is in close contact with the inner surface of the core portion 241, thereby sealing the multiple holes 241h. As a result, leakage of electrolyte from inside the housing 200 through the inside of the inner cylinder portion 240 to the outside can be suppressed. The contact portion 253 is in contact with the outer surface 220a of the second end portion 220 from the outside of the housing 200. The outer shape of the contact 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 housed in the housing 200. The negative insulating plate 400 is provided 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 to cover the positive electrode plate 110, the negative electrode plate 120, and the separator 130 from one side (the Z1 side).

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

[0047] The positive side insulating plate 300 is housed in the housing 200. The positive side insulating plate 300 is provided 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 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 in contact with the conductive film 510, which will be described later. As a result, the positive electrode tab lead 140 and the conductive film 510 are electrically connected. 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 the current path by utilizing the increase in internal pressure of the energy storage cell 10 caused by gas generated due to overcharging of the energy storage cell 10. The current interruption device 500 is provided to seal the opening on the other side (Z2 side) of the outer cylinder portion 210. The current interruption device 500 includes a conductive film 510, a gasket 520, and a bottom disk 530.

[0050] The conductive film 510 is provided 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 outer cap 222 by a connecting member (not shown). As a result, the outer cap 222 is also positively charged.

[0051] The conductive film 510, like the outer cap 222, is provided with a weak portion 511 (thin-walled portion). The conductive film 510 is prone to breaking starting from the weak portion 511 when the internal pressure of the housing 200 increases. 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. As a result, the positive charge of the conductive film 510 is eliminated, as is the positive charge of the outer cap 222. Consequently, the charging and discharging of the energy storage cell 10 is stopped.

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

[0053] The core portion 241 and the second insulating end portion 242 of the inner cylinder portion 240 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] Figure 2 shows the process of injecting electrolyte into a storage cell according to an embodiment. As shown in Figure 2, when injecting electrolyte, for example, the space inside the inner cylinder portion 240 is used. Specifically, the electrolyte is injected into the space inside the inner cylinder portion 240 from the through hole 221 with the first portion 251 of the sealing portion 250 positioned inside the inner cylinder portion 240, without the second portion 252 of the sealing portion 250 being positioned. The presence of the first portion 251 prevents the electrolyte from leaking out from the through hole 231.

[0055] The electrolyte injected into the inner space of the inner cylinder portion 240 permeates through each of the multiple holes 241h, moving from the inside to the outside of the wound electrode body 100, as shown by arrow AR1. This enhances the permeability of the electrolyte into the wound electrode body 100. In addition to the above, the electrolyte may also be injected into the housing 200 from an inlet provided in the housing 200.

[0056] Next, after injecting the electrolyte, the second portion 252 is inserted into the inner cylinder portion 240 so that the contact portion 253 contacts the outer surface 220a. As a result, the electrolyte that was located inside the inner cylinder portion 240 is pushed by the second portion 252 and moves into the housing 200 through the multiple holes 241h. In addition, the multiple holes 241h are sealed by the second portion 252. By stopping the insertion of the second portion 252 while the contact portion 253 is in contact with the outer surface 220a as described above, it is possible to prevent the first portion 251 from being excessively pushed by the second portion 252 and detaching from the inside of the inner cylinder portion 240, and to prevent excessive load from being placed on the second portion 252 and the second end portion 220, which would cause deformation of the second portion 252 and the second end portion 220.

[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 all modifications are made in the sense and scope equivalent to the claims. [Explanation of Symbols]

[0058] 10 Energy storage cell, 100 Winding 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, 220 Second end, 220a Outer surface, 221 Through hole, 222 Outer cap, 223 Insulating layer, 224 Crimped part, 225 Weak part, 230 First end, 230a Outer surface, 231 Through hole, 240 Inner cylinder, 241 Core, 242 Second insulating end, 243 First insulating end, 250 Sealing part, 251 First part, 241h Hole, 252 Second part, 253 Contact part, 300 Positive side insulating plate, 310 First through hole, 320 Second through hole, 400 Negative insulating plate, 410 through hole, 500 current interruption device, 510 conductive film, 511 weak point, 520 gasket, 530 bottom disc.

Claims

[Claim 1] A wound electrode body including a wound positive electrode and a wound negative electrode, A housing that contains the wound electrode body and the electrolyte, It comprises a sealing part, The housing includes an outer cylindrical portion positioned radially outward of the wound electrode body and an inner cylindrical portion that penetrates the hollow portion of the wound electrode body in the axial direction of the wound electrode body. The wound electrode body and the electrolyte are arranged between the outer cylinder and the inner cylinder. The inner cylinder portion is provided with a plurality of holes, The sealing portion includes a portion positioned inside the inner cylinder portion so as to seal the plurality of holes, The sealing portion has a first portion located inside the inner cylinder portion at one end of the inner cylinder portion in a direction parallel to the axial direction, and a second portion extending inside the inner cylinder portion in a direction parallel to the axial direction so as to seal the plurality of holes. The housing includes a first end face located at one end in a direction parallel to the axial direction, and a second end face located at the other end in a direction parallel to the axial direction. The second portion is a storage cell having a contact portion that contacts the second end face from the outside of the housing.

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