Electricity storage unit

Abstract

The utility model relates to an electric power storage unit, which is provided with a winding electrode body and a shell, wherein the winding electrode body comprises a positive electrode and a negative electrode; the case includes: a peripheral wall portion disposed on an outer peripheral side of the wound electrode body and extending in a cylindrical shape in an axial direction of the wound electrode body; and a cover part which is provided at one end of the peripheral wall part in the axial direction and closes the one end. And the cover part is provided with a through hole for communicating the inside and the outside of the shell. The cap portion includes: a positive electrode terminal positioned on an outer side of the case when viewed from the through hole; an insulating portion positioned between the housing and the positive electrode terminal in the axial direction to insulate the housing and the positive electrode terminal from each other; and a connecting member inserted through the through hole and connecting the positive electrode terminal and the positive electrode to each other. Either the circumferential surface of the connecting member facing the through-hole in the radial direction of the wound electrode body or the inner wall of the through-hole facing the connecting member is covered with an insulating material. As a result, the insulation between the battery case and the terminal of the electrode can be improved.

Description

Technical Field

[0001] The utility model relates to an electricity storage unit. Background Art

[0002] For example, Japanese Patent Application Laid-Open No. 11-121041 discloses a structure of a power storage unit in which an electrode terminal is provided in a battery case.

[0003] The above-mentioned electric storage cells have a structure in which an insulator or the like is provided so that the electrode terminals and the battery case do not come into contact with each other. However, in order to suppress a decrease in the performance of the electric storage cells, further improvement in insulation is required. Utility Model Content

[0004] The utility model is completed in order to solve the above-mentioned technical problems, and its purpose is to provide a storage unit which improves the insulation between a battery case and an electrode terminal.

[0005] The utility model relates to a storage unit, which has a wound electrode body including a positive electrode and a negative electrode and a shell for accommodating the wound electrode body. The shell includes: a peripheral wall portion, which is arranged on the outer peripheral side of the wound electrode body and extends in a cylindrical shape along the axial direction of the wound electrode body; and a cover portion, which is arranged at one end of the peripheral wall portion in the axial direction and closes the one end. The cover portion is provided with a through hole connecting the inside and outside of the shell. The cover portion includes: a positive terminal, which is located on the outer side of the shell when viewed from the through hole; an insulating portion, which is located between the shell and the positive terminal in the axial direction to insulate the shell and the positive terminal from each other; and a connecting member, which is inserted into the through hole to connect the positive terminal and the positive electrode to each other. Either the circumferential surface of the connecting member opposite to the through hole in the radial direction of the wound electrode body and the inner wall of the through hole opposite to the connecting member are covered with an insulating material. Thereby, the insulation between the battery shell and the electrode terminal can be improved.

[0006] Since the insulating material is present between the surface of the connecting member and the inner wall of the through hole, the insulation between the case including the lid provided on the peripheral wall and the positive electrode terminal connected to the wound electrode body via the connecting member can be improved.

[0007] In the present invention, the insulating material may abut against the other of the inner wall of the through hole and the surface in the circumferential direction of the connecting member.

[0008] In this way, since the circumferential surface of the connection member and the inner wall of the through hole are covered with the insulating material, the insulation between the case and the positive electrode terminal can be improved.

[0009] Furthermore, in the present invention, the insulating material may have a predetermined thickness and cover the surface of the connecting member in the circumferential direction.

[0010] In this way, since the surface of the connecting member in the circumferential direction is covered with the insulating material, the insulation between the case and the positive electrode terminal can be improved.

[0011] In addition, in the present invention, the insulating material may have a predetermined thickness and cover the inner wall of the through hole.

[0012] In this way, since the inner wall of the through hole is covered with the insulating material, the insulation between the case and the positive electrode terminal can be improved.

[0013] According to the present invention, it is possible to provide a power storage unit in which the insulation between a battery case and an electrode terminal is improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a cross-sectional view showing an example of the structure of the power storage unit according to the present embodiment.

[0015] Figure 2 It is a perspective schematic diagram showing an example of the structure of a wound electrode body in this embodiment.

[0016] Figure 3 It is a plan view showing an example of the structure of the positive electrode current collector plate in this embodiment.

[0017] Figure 4 It is a plan view showing an example of the structure of the negative electrode current collector plate in this embodiment.

[0018] Figure 5 for Figure 1 A magnified view of the area near the positive electrode collector plate.

[0019] Figure 6 It is a partial enlarged view of the vicinity of the positive electrode current collector plate in a modified example.

[0020] Figure 7 This is a partial enlarged view of the vicinity of the positive electrode collector plate in another modified example. DETAILED DESCRIPTION

[0021] The following describes the embodiments of the present invention in detail with reference to the accompanying drawings. In addition, the same or corresponding parts in the drawings are marked with the same reference numerals, and the description is not repeated.

[0022] Figure 1 1 is a cross-sectional view showing an example of the structure of the power storage unit 100 according to the present embodiment. Figure 1 As shown, the electricity storage cell 100 includes a wound electrode body 1 , a case 2 , a positive electrode terminal 3 , a positive electrode collector plate 4 , an outer gasket 5 , an inner gasket 6 , a negative electrode collector plate 7 , a polymer ring 8 , and a sealing plug 9 .

[0023] The wound electrode body 1 is accommodated in a case 2. The case 2 has a cylindrical shape. The wound electrode body 1 is wound so as to have a cylindrical shape like the case 2. That is, the power storage unit 100 is a cylindrical battery. In addition, the case 2 is formed of copper, aluminum, or the like.

[0024] The shell 2 includes a top plate portion 2a, a peripheral wall portion 2c and a sealing plate 2d. The peripheral wall portion 2c is arranged on the outer peripheral side of the wound electrode body 1 and has a cylindrical shape. The top plate portion 2a is connected to the end of the peripheral wall portion 2c on the Z1 side in the Z direction. The top plate portion 2a is formed integrally with the peripheral wall portion 2c. The top plate portion 2a covers (closes) the opening on the Z1 side of the peripheral wall portion 2c. The sealing plate 2d is connected to the end of the peripheral wall portion 2c on the Z2 side in the Z direction. The sealing plate 2d covers (closes) the opening on the Z2 side of the peripheral wall portion 2c. A riveted portion 2e riveted to the outer peripheral edge of the sealing plate 2d is formed at the end of the peripheral wall portion 2c on the Z2 side. The riveted portion 2e is formed in a circular ring shape. In addition, the top plate portion 2a is an example of a "cover portion" of the utility model.

[0025] The wound electrode body 1 includes a positive electrode sheet 10, a negative electrode sheet 20, and a separator 30. The separator 30 is provided between the positive electrode sheet 10 and the negative electrode sheet 20. The separator 30 enables ions (e.g., lithium ions) to travel between the positive electrode sheet 10 (positive electrode active material) and the negative electrode sheet 20 (negative electrode active material), and separates the positive electrode sheet 10 from the negative electrode sheet 20. The wound electrode body 1 is composed of an electrode plate group in which the positive electrode sheet 10 and the negative electrode sheet 20 are wound with the separator 30 interposed therebetween.

[0026] The positive electrode sheet 10 includes a positive electrode current collector 11 and a positive electrode composite material layer 12. The positive electrode composite material layer 12 is applied to both radial surfaces of the positive electrode current collector 11 (more specifically, the positive electrode coating portion 11a). The positive electrode composite material layer 12 is in close contact with the separator 30.

[0027] The positive electrode current collector 11 is formed of, for example, aluminum, etc. The positive electrode composite material layer 12 is formed by applying a positive electrode slurry to the surface of the positive electrode current collector 11 and drying it. The positive electrode slurry is a slurry prepared by kneading the materials of the positive electrode composite material layer 12 (positive electrode active material and binder, etc.) with a solvent.

[0028] The positive electrode current collector 11 includes a positive electrode coating portion 11 a and a positive electrode uncoated portion 11 b. The positive electrode coating portion 11 a is a portion of the positive electrode current collector 11 on which the positive electrode mixture layer 12 is coated (an unexposed portion).

[0029] The positive electrode uncoated portion 11b is an exposed portion of the positive electrode current collector 11 that is not covered by the positive electrode mixture layer 12. The positive electrode uncoated portion 11b is located closer to the Z1 side than 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.

[0030] The positive electrode uncoated portion 11b is bent radially inward by contacting the positive electrode collector plate 4 disposed on the Z1 side. The positive electrode collector plate 4 is thereby positively charged. The positive electrode uncoated portion 11b is joined to the positive electrode collector plate 4 by welding.

[0031] The negative electrode sheet 20 includes a negative electrode current collector 21 and a negative electrode composite material layer 22. The negative electrode composite material layer 22 is applied to both radial surfaces of the negative electrode current collector 21 (more specifically, the negative electrode coating portion 21a). The negative electrode composite material layer 22 is in close contact with the separator 30.

[0032] The negative electrode current collector 21 is formed of, for example, copper, etc. The negative electrode composite material layer 22 is formed by applying negative electrode slurry to the surface of the negative electrode current collector 21 and drying it. The negative electrode slurry is a slurry prepared by kneading the materials of the negative electrode composite material layer 22 (negative electrode active material and binder, etc.) with a solvent.

[0033] The negative electrode current collector 21 includes a negative electrode coating portion 21 a and a negative electrode uncoated portion 21 b. The negative electrode coating portion 21 a is a portion of the negative electrode current collector 21 coated with the negative electrode mixture layer 22 (an unexposed portion).

[0034] The negative electrode uncoated portion 21b is a portion of the negative electrode current collector 21 that is not covered by the negative electrode mixture layer 22 and is exposed. The negative electrode uncoated portion 21b is located closer to the Z2 side than the negative electrode coated portion 21a. Specifically, the negative electrode uncoated portion 21b protrudes from the negative electrode coated portion 21a to the Z2 side.

[0035] The negative electrode uncoated portion 21b is bent radially inward by contacting the negative electrode collector plate 7 disposed on the Z2 side. As a result, the negative electrode collector plate 7 is negatively charged. The negative electrode uncoated portion 21b is joined to the negative electrode collector plate 7 by welding.

[0036] Figure 2 1 is a perspective schematic diagram showing an example of the structure of the wound electrode body 1 in this embodiment. Figure 2 As shown in FIG. 1 , the positive electrode sheet 10 , the negative electrode sheet 20 , and the separator 30 of the wound electrode body 1 are wound so as to surround the periphery of the winding axis α. Figure 2 In FIG. 1 , for convenience, the wound electrode body 1 is shown in a state where the winding is slightly unwound so that the wound state of the wound electrode body 1 can be easily understood.

[0037] Refer again Figure 1 The positive terminal 3 includes a disk portion 3a and a rivet portion 3b. The disk portion 3a is exposed by being arranged outside the housing 2. The rivet portion 3b is connected to the disk portion 3a. The rivet portion 3b is arranged to extend from the center of the disk portion 3a to the Z2 side. In addition, the positive terminal 3 is formed of aluminum. The rivet portion 3b is an example of a "connecting member" of the present utility model.

[0038] The plate portion 3a is disposed on the top plate portion 2a of the housing 2. The top plate portion 2a is arranged to be perpendicular to the Z direction. A through hole 2b (see FIG. 2 ) is provided on the top plate portion 2a to connect the inside and the outside of the housing 2. Figure 5 ). The rivet portion 3b extends from the disk portion 3a disposed outside the housing 2 through the through hole 2b to the inside of the housing 2. In addition, the Z direction is an example of the "axial direction" of the present invention.

[0039] The positive electrode collector plate 4 is housed in the housing 2. The positive electrode collector plate 4 (sheet portion 4d described later) is welded to the positive electrode uncoated portion 11b of the positive electrode sheet 10. As a result, the positive electrode collector plate 4 is positively charged. The positive electrode collector plate 4 is welded to the end portion 3c on the Z2 side of the rivet portion 3b. As a result, the positive terminal 3 is positively charged.

[0040] The external gasket 5 is provided outside the case 2. Specifically, the external gasket 5 is disposed between the disk portion 3a of the positive electrode terminal 3 and the top plate portion 2a of the case 2. The positive electrode terminal 3 is thereby insulated from the case 2. The external gasket 5 is an example of the "insulating portion" of the present invention.

[0041] The inner gasket 6 is provided inside the case 2. Specifically, the inner gasket 6 is disposed between the case 2 and the positive electrode collector plate 4. Thus, the case 2 and the positive electrode collector plate 4 are insulated. In addition, the rivet portion 3b penetrates the inner gasket 6 and contacts the positive electrode collector plate 4.

[0042] The negative electrode collector plate 7 is housed in the case 2. The negative electrode collector plate 7 (sheet portion 7d described later) is welded to the negative electrode uncoated portion 21b of the negative electrode sheet 20. Thus, the negative electrode collector plate 7 is negatively charged. In addition, the negative electrode collector plate 7 is in contact with the case 2. Thus, the case 2 is negatively charged.

[0043] The polymer ring 8 is provided between the outer peripheral edge of the sealing plate 2d and the caulking portion 2e formed on the peripheral wall portion 2c. The polymer ring 8 has a circular ring shape.

[0044] The through hole 2f provided at the center of the sealing plate 2d is closed by the sealing plug 9. The sealing plug 9 is provided so as to penetrate the through hole 2f and the through hole 7g provided at the center of the negative electrode current collector plate 7.

[0045] Figure 3 FIG. 4 is a top view showing an example of the structure of the positive electrode collector plate 4 in this embodiment. Figure 3 As shown, the positive electrode current collector plate 4 has a disc shape and includes a central portion 4a, spokes 4b, an outer peripheral edge portion 4c, and a tab portion 4d.

[0046] The center portion 4a is provided at the center of the positive electrode current collector plate 4. The rivet portion 3b is joined to the center portion 4a. The spokes 4b are provided to extend radially outward from the center portion 4a. Six spokes 4b are provided at equal angular intervals around the center portion 4a of the positive electrode current collector plate 4.

[0047] The outer peripheral portion 4c is provided at the outer peripheral edge of the positive electrode current collector plate 4. Six spokes 4b connect the outer peripheral portion 4c and the central portion 4a, respectively. The spokes 4b are formed to bend in the Z direction. In addition, the central portion 4a of the positive electrode current collector plate 4 moves (displaces) the most in the Z direction.

[0048] Through holes 4e are formed between the spokes 4b adjacent to each other in the circumferential direction. That is, six through holes 4e are formed. A sheet 4d is provided inside each of the six through holes 4e. The six sheets 4d are connected to the outer peripheral edge 4c via connecting portions 4f. In addition, the six sheets 4d have a shape that gradually tapers toward the radial inside.

[0049] Figure 4 FIG. 2 is a top view showing an example of the structure of the negative electrode collector plate 7 in this embodiment. Figure 4 As shown, the negative electrode current collector plate 7 has a disc shape and includes a central portion 7a, spokes 7b, an outer peripheral edge portion 7c, and a tab portion 7d.

[0050] The center portion 7a is provided at the center of the negative electrode current collector plate 7. The spokes 7b are provided so as to extend radially outward from the center portion 7a. Six spokes 7b are provided at equal angular intervals around the center portion 7a of the negative electrode current collector plate 7.

[0051] The outer peripheral portion 7c is provided at the outer peripheral edge of the negative electrode current collector plate 7. Six spokes 7b connect the outer peripheral portion 7c and the central portion 7a, respectively. Each spoke 7b is formed to bend in the Z direction. The outer peripheral portion 7c of the negative electrode current collector plate 7 moves (displaces) the most in the Z direction.

[0052] Through holes 7e are formed between the spokes 7b adjacent to each other in the circumferential direction. That is, six through holes 7e are formed. The sheet portions 7d are arranged at positions corresponding to the six through holes 7e. Specifically, the six sheet portions 7d are respectively arranged on the inner sides of the corresponding through holes 7e. The six sheet portions 7d are respectively connected to the central portion 7a through the connecting portions 7f. In addition, the six sheet portions 7d have a shape that gradually tapers toward the radial inner side.

[0053] In the storage cell 100 having the above structure, the outer gasket 5 of the insulator is provided to prevent the positive terminal 3 from contacting the case 2 . However, in order to suppress the performance degradation of the storage cell 100 , it is required to further improve the insulation between the positive terminal 3 and the case 2 .

[0054] Therefore, in the present embodiment, either the surface of the rivet portion 3 b facing the through hole 2 b in the radial direction of the wound electrode body 1 or the inner wall of the through hole 2 b facing the rivet portion 3 b is covered with an insulating material.

[0055] In this way, since insulating material exists between the surface of the rivet portion 3b and the inner wall of the through hole 2b, the insulation between the case 2 including the top plate portion 2a provided on the peripheral wall portion 2c and the positive electrode terminal 3 connected to the wound electrode body 1 via the rivet portion 3b can be improved.

[0056] The following uses Figure 1 and Figure 5 This will be described in more detail. Figure 5 for Figure 1 A partial enlarged view of the vicinity of the positive electrode collector plate 4. Figure 1 and Figure 5 As shown, in this embodiment, a hollow cylindrical insulating material 40 is provided in a manner covering the entire circumference of the rivet portion 3b of the positive terminal 3 around the axis. The hollow cylindrical insulating material 40 is provided in a manner penetrating the external gasket 5, the top plate portion 2a, and the internal gasket 6. Furthermore, the outer peripheral portion of the hollow cylindrical insulating material 40 abuts against the inner wall of the through hole of the external gasket 5, the inner wall of the through hole 2b of the top plate portion 2a, and the inner wall of the through hole of the internal gasket 6. The end 3c of the rivet portion 3b is welded to the positive electrode collector plate 4.

[0057] By covering the entire circumference of the rivet portion 3b around the axis with the insulating material 40, the insulation between the rivet portion 3b and the inner wall of the through hole 2b (i.e., the top plate portion 2a) is improved. The insulation between the positive terminal 3 and the housing 2 is thereby improved. As an insulating material, any known insulating material is sufficient, and there is no particular limitation, for example, various resins such as silicon or ceramics can also be used. The insulating material 40 is preliminarily covered on the rivet portion 3b in a manner such as to form a predetermined hollow cylindrical shape. For example, in a state where an internal gasket 6 and a positive electrode collector plate 4 are provided on the inner side of the top plate portion 2a, and an external gasket 5 is provided on the outer side of the top plate portion 2a, the rivet portion 3b of the positive terminal 3 is provided in a state where the entire circumference is covered by the insulating material 40, penetrating the through hole of the external gasket 5, the through hole 2b of the top plate portion 2a, and the through hole of the internal gasket 6. Then, the end 3c of the rivet portion 3b is welded to the positive electrode collector plate 4.

[0058] As described above, according to the storage battery cell 100 of the present embodiment, since the insulating material 40 is present between the surface of the rivet portion 3b and the inner wall of the through hole 2b, the insulation between the case 2 including the top plate portion 2a provided on the peripheral wall portion 2c and the positive electrode terminal 3 connected to the wound electrode body 1 via the rivet portion 3b can be improved. Therefore, a storage battery cell having improved insulation between the battery case and the electrode terminal can be provided.

[0059] Modifications are described below.

[0060] In the above-mentioned embodiment, the case where the insulating material 40 is pre-covered on the entire circumference of the rivet portion 3b is described as an example, but for example, a gap portion may be formed on the entire circumference of the axis of the rivet portion 3b, and the insulating material 40 may be injected into the gap portion to cover the rivet portion 3b, or a structure in which the entire circumference of the inner wall of the through hole 2b is pre-covered in an annular shape with the insulating material 40, and the rivet portion 3b is inserted into the inner through hole formed by the insulating material 40.

[0061] Furthermore, in the above-mentioned embodiment, a situation is described in which the surface of the rivet portion 3b and the inner wall of the through hole 2b are covered with the insulating material 40 and the insulating material 40 abuts against the inner wall of the through hole 2b, but as long as at least one of the surface of the rivet portion 3b and the inner wall of the through hole 2b is covered with the insulating material 40, it is also possible that the insulating material 40 does not abut against the other side.

[0062] For example, the circumferential surface of the rivet portion 3b may be covered with an insulating member having a predetermined thickness. The predetermined thickness is a thickness capable of ensuring insulation between the rivet portion 3b and the inner wall of the through hole 2b, and is set, for example, through experiments. Figure 6 FIG. 4 is a partial enlarged view of the vicinity of the positive electrode collector plate 4 in a modified example. Figure 6 As shown, it can also be replaced by Figure 1 The insulating material 40 is not provided, and the circumferential surface of the rivet portion 3b is covered with a hollow cylindrical insulating material 41 having a predetermined thickness, and a hollow cylindrical gasket 42 is provided in a manner to fill the gap between the insulating material 41 and the inner wall of the through hole 2b. In this way, the insulation between the positive terminal 3 and the case 2 can also be improved.

[0063] Alternatively, the inner wall of the through hole 2b may be covered with an insulating member having a predetermined thickness. Figure 7 FIG. 4 is a partial enlarged view of the vicinity of the positive electrode collector plate 4 in another modified example. Figure 7 As shown, it can also be replaced by Figure 1 The insulating material 40 is not provided, and the inner wall of the through hole 2b is covered with a hollow cylindrical insulating material 43 having a predetermined thickness, and a hollow cylindrical gasket 44 is provided in a manner to fill the gap between the inner peripheral portion of the insulating material 43 and the surface of the rivet portion 3b. In this way, the insulation between the positive terminal 3 and the case 2 can also be improved.

[0064] In addition, all or part of the above-mentioned variations can be appropriately combined for implementation. It should be considered that the embodiments disclosed this time are illustrative rather than restrictive in all aspects. The scope of the utility model is not represented by the above description, but by the technical solution, and is intended to include all changes within the meaning and scope equivalent to the technical solution.

Claims

1. A power storage unit, characterized in that: The invention comprises a wound electrode body including a positive electrode and a negative electrode and a casing for accommodating the wound electrode body. The housing comprises: a peripheral wall portion, arranged on the outer peripheral side of the wound electrode body, and extending in a cylindrical shape along the axial direction of the wound electrode body; and A cover portion is provided at one end of the peripheral wall portion in the axial direction to close the one end. The cover is provided with a through hole connecting the inside and the outside of the housing. The cover portion comprises: a positive terminal located on the outer side of the housing when viewed from the through hole; an insulating portion located between the case and the positive terminal in the axial direction so as to insulate the case and the positive terminal from each other; and a connecting member inserted into the through hole to connect the positive electrode terminal and the positive electrode to each other, Either one of a circumferential surface of the connecting member facing the through hole in the radial direction of the wound electrode body and an inner wall of the through hole facing the connecting member is covered with an insulating material.

2. The power storage unit according to claim 1, characterized in that: The insulating material is in contact with the other of the inner wall of the through hole and the surface in the circumferential direction of the connecting member.

3. The power storage unit according to claim 1, characterized in that: The insulating material has a predetermined thickness and covers a surface of the connecting member in a circumferential direction.

4. The power storage unit according to claim 1, characterized in that: The insulating material has a predetermined thickness and covers the inner wall of the through hole.

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