Electricity storage unit

Abstract

The utility model provides an electric power storage unit capable of improving the permeability of electrolyte to a wound electrode body. An electricity storage cell (10) is provided with a wound electrode body (100) comprising a positive electrode and a negative electrode that are wound, a case (200) that houses the wound electrode body (100) and an electrolyte solution therein, and a sealing part (250), the case (200) comprising an outer cylinder part (210) provided on the outside in the radial direction of the wound electrode body (100) and an inner cylinder part (240) that penetrates through the hollow part of the wound electrode body (100) in the axial direction of the wound electrode body (100). The wound electrode body (100) and the electrolyte are provided between the outer cylinder section (210) and the inner cylinder section (240), the inner cylinder section (240) is provided with a plurality of hole sections (241h), and the sealing section (250) includes a portion provided on the inside of the inner cylinder section (240) to seal the plurality of hole sections (240).

Description

Technical Field

[0001] The utility model relates to a power storage unit. Background Art

[0002] Japanese Patent Publication No. 2001-093566 (Patent Document 1) discloses a cylindrical battery, which is characterized in that the core material of the cylindrical battery is a hollow material, allowing air to pass through the hollow part of the hollow material. Patent Document 1 records that the above-mentioned structure can promote the heat dissipation effect and prevent the performance of the cylindrical battery from deteriorating.

[0003] However, in the configuration of Patent Document 1, the penetration of the electrolyte solution is not fully considered, and there is a concern that the electrolyte solution may have difficulty in uniformly penetrating into the electrode body. Utility Model Content

[0004] The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide a power storage unit capable of improving the permeability of an electrolyte solution into a wound electrode body.

[0005] The storage unit of the utility model comprises: a wound electrode body including a wound positive electrode and a wound negative electrode, a shell that accommodates the wound electrode body and an electrolyte inside, and a sealing portion. The shell includes an outer cylinder portion arranged on the radially outer side of the wound electrode body, and an inner cylinder 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 portion and the inner cylinder portion. A plurality of holes are provided in the inner cylinder portion. The sealing portion includes a portion arranged on the inner side of the inner cylinder portion to seal the plurality of holes.

[0006] In the storage unit of the utility model, the above-mentioned sealing part may have: a first part, which is arranged on the inner side of the above-mentioned inner cylinder part at one end side of the above-mentioned inner cylinder part in a direction parallel to the above-mentioned axial direction; and a second part, which extends on the inner side of the above-mentioned inner cylinder part along a direction parallel to the above-mentioned axial direction to seal the above-mentioned multiple hole parts.

[0007] In the storage unit of the present invention, the above-mentioned shell may include a first end face located on one end side in a direction parallel to the above-mentioned axial direction and a second end face located on the other end side in a direction parallel to the above-mentioned axial direction, and the above-mentioned second part may have an abutting portion abutting against the above-mentioned second end face from the outside of the above-mentioned shell.

[0008] According to the present invention, it is possible to provide a power storage cell capable of improving the permeability of an electrolyte solution into a wound electrode body. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1 This is a cross-sectional view of a power storage unit according to one embodiment.

[0010] Figure 2 It is a diagram showing a state where an electrolyte solution is injected into a power storage unit according to an embodiment. DETAILED DESCRIPTION

[0011] The following is a detailed description of the embodiments of the present invention with reference to the accompanying drawings. In the embodiments shown below, the same or corresponding parts in the drawings are denoted by the same reference numerals, and their description is omitted.

[0012] Figure 1 2 is a cross-sectional view of a power storage unit according to one embodiment. Figure 1 Next, the power storage unit 10 of the embodiment will be described. The power storage unit 10 is, for example, a lithium-ion battery mounted on a vehicle. In addition, the use and type of the power storage unit are not limited to the above examples.

[0013] like Figure 1 As shown, the power storage cell 10 is a tubular battery, more specifically, a cylindrical battery. The power storage cell 10 includes a wound electrode body 100 , a case 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 disposed 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 and allows ions (e.g., lithium ions) to pass between the positive electrode plate 110 (positive electrode active material) and the negative electrode plate 120 (negative electrode active material). The positive electrode plate 110 includes a positive electrode collector and a positive electrode composite material layer. The positive electrode composite material layer is coated on a portion of the positive electrode collector. That is, the positive electrode collector includes a coated portion coated with the positive electrode composite material layer and an uncoated portion not coated with the positive electrode composite material layer.

[0016] For example, aluminum or the like can be used as the positive electrode collector. The positive electrode composite material layer is formed by applying the positive electrode slurry to the surface of the positive electrode collector and drying it. The positive electrode slurry refers to a slurry prepared by kneading the materials of the positive electrode composite material layer (positive electrode active material, binder, etc.) with a solvent. The positive electrode composite material layer is in close contact with the separator 130. The thickness of the positive electrode composite material layer is, for example, greater than 0.1 μm and less than 1000 μm.

[0017] The negative electrode plate 120 includes a negative electrode collector and a negative electrode composite material layer. The negative electrode composite material layer is coated on a portion of the negative electrode collector. That is, the negative electrode collector includes a coated portion coated with the negative electrode composite material layer and an uncoated portion not coated with the negative electrode composite material layer.

[0018] For example, copper foil can be used as the negative electrode collector. The negative electrode composite material layer is formed by applying the negative electrode slurry to the surface of the negative electrode collector and drying it. The negative electrode slurry refers to a slurry prepared by mixing the materials of the negative electrode composite material layer (negative electrode active material, binder, etc.) with a solvent. The negative electrode composite material layer is in close contact with the separator 130. The thickness of the negative electrode composite material layer is, for example, greater than 0.1 μm and less than 1000 μm.

[0019] The negative electrode tab lead 150 is provided so as to protrude from the negative electrode collector of the negative electrode plate 120 toward one side ( Z1 side) in the axial direction Z.

[0020] The positive electrode tab lead 140 is provided so as to protrude from the positive electrode collector of the positive electrode plate 110 toward the other side ( Z2 side) in the axial direction Z.

[0021] The case 200 accommodates the wound electrode body 100 and the electrolyte solution therein. The case 200 has a substantially cylindrical shape, and a sealing portion 250 described below is provided in a hollow portion of the case 200 .

[0022] The housing 200 includes an outer cylinder portion 210 , a first end portion 230 , a second end portion 220 , and an inner cylinder portion 240 .

[0023] The outer cylinder 210 is cylindrical and extends in the axial direction Z. The outer cylinder 210 constitutes the outer peripheral wall of the case 200. The outer cylinder 210 is arranged outside the radial direction R of the wound electrode body 100. The outer cylinder 210 is formed of copper or aluminum. The outer cylinder 210 is in contact with the collector of the negative electrode plate 120 arranged on the outermost periphery of the wound electrode body 100.

[0024] 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 231 penetrating in a direction parallel to the axial direction Z is provided in the center of the first end portion 230 .

[0025] The first end 230 has an outer surface 230a. The outer surface 230a constitutes a first end surface 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.

[0026] The periphery of the first end portion 230 is connected to the outer cylinder portion 210. The first end portion 230 is formed integrally with the outer cylinder portion 210. The first end portion 230 is formed of copper, aluminum or the like.

[0027] The first end portion 230 contacts the negative electrode tab lead 150. Thus, the negative electrode tab lead 150 is electrically connected to the first end portion 230. Therefore, the first end portion 230, the outer cylinder portion 210, and the rivet portion 224 described later are all negatively charged.

[0028] 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. A through hole (second through hole) 221 penetrating in a direction parallel to the axial direction Z is provided on the second end portion 220. The second end portion 220 has an outer surface 220a. The outer surface 220a constitutes a second end face of the shell 200. The outer surface 220a is located on the other end side of the shell 200 in a direction parallel to the axial direction Z.

[0029] The second end portion 220 has an outer cover 222 , an insulating layer 223 , and a rivet portion 224 .

[0030] The external cover 222 functions as an external terminal. A bus bar is electrically connected to the external cover 222. The external cover 222 is provided with a fragile portion 225 (thin wall portion).

[0031] When the internal pressure of the housing 200 increases, the outer cover 222 is easily broken from the fragile portion 225. As a result, the gas is rapidly discharged to the outside of the housing 200. The through hole 221 is provided in the outer cover 222. The outer cover 222 is formed of copper, aluminum or the like.

[0032] The insulating layer 223 covers the outer peripheral end of the outer cover 222. The insulating layer 223 insulates the outer cover 222 from the rivet portion 224.

[0033] The rivet portion 224 is connected to the end of the outer cylinder portion 210 located on the opposite side to the first end portion 230 in the direction parallel to the axial direction Z. The rivet portion 224 is formed integrally with the outer cylinder portion 210. The rivet portion 224 rivets the outer peripheral edge of the outer cover 222 (and the conductive film 510 described later) via the insulating layer 223. The rivet portion 224 is formed of copper, aluminum, or the like.

[0034] The inner cylinder portion 240 extends from the through hole 231 to the through hole 221 along the axial direction Z. 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 inner side of the radial direction R of the wound electrode body 100. In other words, the wound electrode body 100 (and the electrolyte) are disposed between the outer cylinder portion 210 and the inner cylinder portion 240.

[0035] The inner cylinder portion 240 includes a core portion 241, a first insulating end portion 243, and a second insulating end portion 242. In addition, the inner cylinder portion 240 is provided with a plurality of holes 241h.

[0036] The core 241 is made of a hollow core material and constitutes most of the inner cylinder 240. The core 241 is disposed inside the radial direction R of the wound electrode body 100. The core 241 can be used as a core material when the electrode plate group is wound to form the wound electrode body 100. The core 241 can be made of a metal such as copper or aluminum.

[0037] 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 a direction parallel to the circumferential direction and the axial direction Z. The plurality of holes 241h function as injection ports when injecting electrolyte.

[0038] The first insulating end portion 243 is located on one side (Z1 side) of the core portion 241 in a direction parallel to the axial direction Z. The first insulating end portion 243 insulates the core portion 241 from the first end portion 230. The core portion 241 is fixed to the first end portion 230 via the first insulating end portion 243. Specifically, a fitting portion that fits with the first insulating end portion 243 is provided around the through hole 231 in the first end portion 230, and the core portion 241 is fixed to the first end portion 230 by fitting the first insulating end portion 243 into the fitting portion.

[0039] The second insulating end portion 242 is provided on the other side (Z2 side) of the core portion 241 in a direction parallel to the axial direction Z. The second insulating end portion 242 insulates the core portion 241 from the second end portion 220. The core portion 241 is fixed to the second end portion 220 via the second insulating end portion 242. Specifically, a fitting portion that fits with the second insulating end portion 242 is provided around the through hole 221 in the second end portion 220, and the core portion 241 is fixed to the second end portion 220 by fitting the fitting portion to the second insulating end portion 242.

[0040] The sealing part 250 is used to seal the plurality of holes 241 h and includes a first portion 251 and a second portion 252 .

[0041] The first portion 251 is provided inside the inner cylinder portion 240 at one end side of the inner cylinder portion 240 in a direction parallel to the axial direction Z. The first portion 251 is located closer to the first end portion 230 than the hole portion 241h located closest to the direction parallel to the axial direction Z among the plurality of hole portions 241h. The first portion 251 seals, for example, from the through hole 231 to the hole portion 241h located closest to the direction parallel to the axial direction Z among the plurality of hole portions 241h inside the inner cylinder portion 240.

[0042] The second part 252 includes an extension portion and abutment portion 253 extending from the first part 251 to the through hole 221 along a direction parallel to the axial direction Z on the inner side of the inner cylinder 240. The extension portion is arranged on the inner side of the inner cylinder 240 to seal a plurality of hole portions 241h. The outer surface of the extension portion is in close contact with the inner surface of the core 241, thereby sealing a plurality of hole portions 241h. Therefore, it is possible to suppress the electrolyte from leaking from the inside of the housing 200 through the inside of the inner cylinder 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.

[0043] The power storage unit 10 further includes a positive-side insulating plate 300 , a negative-side insulating plate 400 , and a current interrupt device (Current Interrupt Device) 500 .

[0044] The negative insulating plate 400 is accommodated in the case 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 case 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 the one side (Z1 side).

[0045] The negative side insulating plate 400 has a through hole 410. The negative electrode tab lead 150 is inserted through the through hole 410. Thus, the negative electrode tab lead 150 is electrically connected to the first end portion 230. The inner cylinder portion 240 (more specifically, the core portion 241 and the first insulating end portion 243) is also inserted through the through hole 410.

[0046] The positive insulating plate 300 is accommodated in the case 200. The positive insulating plate 300 is used to insulate the wound electrode body 100 (more specifically, the negative electrode plate 120 and the separator 130) from the case 200. The positive 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).

[0047] 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 to contact the conductive film 510 described later. Thus, the positive electrode tab lead 140 is electrically connected to the conductive film 510. The inner cylinder 240 (core 241) is inserted through the second through hole 320.

[0048] The current interruption device 500 is an element that interrupts the current path by utilizing the increase in the cell internal pressure caused by the gas generated by overcharging of the power storage cell 10. The current interruption device 500 is provided to seal the opening on the other side (Z2 side) of the outer cylinder 210. The current interruption device 500 includes a conductive film 510, a gasket 520, and a chassis 530.

[0049] The conductive film 510 is provided so as to seal the opening of the other side (Z2 side) of the outer cylinder 210. The conductive film 510 is in contact with the positive electrode tab lead 140. Thus, the conductive film 510 is positively charged. In addition, the conductive film 510 is electrically connected to the outer cover 222 via a connecting member (not shown). Thus, the outer cover 222 is also positively charged.

[0050] The conductive film 510 is provided with a fragile portion 511 (thin-walled portion) similarly to the external cover 222. When the internal pressure of the housing 200 rises, the conductive film 510 is easily broken from the fragile portion 511. When the conductive film 510 is broken due to the increase in the 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, and the positive charge of the external cover 222 is also eliminated. Therefore, the charging and discharging of the storage cell 10 is stopped.

[0051] The gasket 520 is located on the wound electrode body 100 side of the conductive film 510. The chassis 530 is connected to the conductive film 510 via the gasket 520.

[0052] The core portion 241 and the second insulating end portion 242 in 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 chassis 530.

[0053] Figure 2 1 is a diagram showing a state where an electrolyte is injected into a power storage unit according to one embodiment. Figure 2 As shown, when injecting the electrolyte, for example, the space inside the inner cylinder 240 is used. Specifically, in a state where the second portion 252 of the sealing portion 250 is not provided inside the inner cylinder 240, but the first portion 251 is provided, the electrolyte is injected from the through hole 221 into the inner space of the inner cylinder 240. By providing the first portion 251, it is possible to prevent the electrolyte from leaking from the through hole 231.

[0054] The electrolyte injected into the inner space of the inner cylinder 240 passes through the plurality of holes 241h, and penetrates into the wound electrode body 100 from the inside to the outside of the wound electrode body 100 as indicated by arrows AR1. This can improve the permeability of the electrolyte into the wound electrode body 100. In addition to the above method, the electrolyte may be injected into the case 200 from an injection port provided in the case 200.

[0055] Next, after the electrolyte is injected, the second part 252 is inserted into the inner side of the inner cylinder 240 so that the contact part 253 contacts the outer surface 220a. As a result, the electrolyte located inside the inner cylinder 240 is pushed by the second part 252 and moves into the housing 200 through the plurality of holes 241h. In addition, the plurality of holes 241h are sealed by the second part 252. As described above, by stopping the insertion of the second part 252 in a state where the contact part 253 contacts the outer surface 220a, it is possible to prevent the first part 251 from being excessively pushed by the second part 252 and detaching from the inner side of the inner cylinder 240, or to prevent the second part 252 and the second end 220 from being deformed due to excessive load being applied to the second part 252 and the second end 220.

Claims

1. A power storage unit, characterized in that: have: A wound electrode body comprising a wound positive electrode and a wound negative electrode; a housing for accommodating the wound electrode body and the electrolyte; and Sealing part; The case includes an outer cylindrical portion provided on the radially outer side of the wound electrode body and an inner cylindrical portion penetrating 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 disposed between the outer cylinder and the inner cylinder. The inner cylinder is provided with a plurality of holes. The sealing portion includes a portion provided inside the inner cylinder portion to seal the plurality of hole portions.

2. The power storage unit according to claim 1, characterized in that: The sealing portion includes: a first portion, which is arranged on the inner side of the inner cylinder portion at one end side of the inner cylinder portion in a direction parallel to the axial direction; and a second portion, which extends on the inner side of the inner cylinder portion in a direction parallel to the axial direction to seal the multiple hole portions.

3. The power storage unit according to claim 2, characterized in that: The housing includes a first end surface located at one end side in a direction parallel to the axial direction and a second end surface located at the other end side in a direction parallel to the axial direction. The second portion has a contact portion that contacts the second end surface from the outside of the housing.

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