Secondary batteries

Abstract

To provide a secondary battery that can secure the insulating property between a lid member and an electrode terminal while the size is reduced.SOLUTION: In a secondary battery 1, an upper part 13a of an electrode terminal 13 is disposed to fall within the range where a concave part 22 is formed with respect to a plane direction of an upper surface 12a of a lid member 12, a resin member 15 is disposed between the upper part 13a of the electrode terminal 13 and the concave part 22, and on the upper surface 12a of the lid member 12, at a position between a top surface part 21 and the concave part 22 in the plane direction of the upper surface 12a, an intermediate part 24 is formed at the position between the top surface part 21 and the concave part 22 with respect to a plate thickness direction of the lid member 12.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present disclosure relates to secondary batteries. [Background technology]

[0002] In a secondary battery disclosed in Patent Document 1 as a conventional technique, an electrode terminal is provided in a recess of a lid member that seals the opening of a container body, and a gasket is provided between the lid member and the electrode terminal to ensure insulation between the lid member and the electrode terminal. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2019-179664 Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the secondary battery disclosed in Patent Document 1, the electrode terminals are formed outside the recessed portion in the planar direction of the upper surface of the lid member, which results in a large lid member and electrode terminals, resulting in a large secondary battery.

[0005] Therefore, the present disclosure has been made to solve the above-mentioned problems, and aims to provide a secondary battery that can be miniaturized while ensuring insulation between the lid member and the electrode terminals. [Means for solving the problem]

[0006] One aspect of the present disclosure made to solve the above problems includes a case having an opening and accommodating an electrode body, a plate-shaped lid member sealing the opening, and an electrode terminal provided on the lid member and connected to the electrode body, the lid member having a first surface which is a surface on one side in a plate thickness direction of the lid member and a second surface which is a surface on the other side in the plate thickness direction of the lid member, a top surface portion and a recessed portion formed at a position closer to the second surface than the top surface portion in the plate thickness direction of the lid member, and the electrode terminal passes through a through hole formed in the lid member at the position of the recessed portion and is connected to the lid member. In the secondary battery arranged across the first surface side to the second surface side of the member, a portion of the electrode terminal arranged on the first surface side with respect to the lid member is arranged so as to fall within a range in which the recess is formed in a surface direction of the first surface, a resin member is arranged between the portion of the electrode terminal arranged on the first surface side with respect to the lid member and the recess, and an intermediate portion is formed on the first surface of the lid member at a position between the top surface portion and the recess in the surface direction of the first surface, and at a position between the top surface portion and the recess in a plate thickness direction of the lid member. the intermediate portion is formed at a position outside a portion of the electrode terminal that is disposed on the first surface side with respect to the cover member in a planar direction of the first surface; It is characterized by:

[0007] According to this aspect, the electrode terminal is disposed within the recess in the planar direction of the first surface of the lid member, and therefore the lid member and the electrode terminal can be made smaller, thereby enabling the secondary battery to be made smaller.

[0008] Furthermore, since the lid member has an intermediate portion between the top surface and the recess, the distance between the top surface of the lid member and the electrode terminal, and the distance between the intermediate portion of the lid member and the electrode terminal can be increased, thereby ensuring insulation between the lid member and the electrode terminal.

[0009] Furthermore, when the lid member is formed, for example, by press processing, the stress acting on the lid member is dispersed to the middle part and is less likely to concentrate in the recess, thereby suppressing the occurrence of cracks in the recess and improving the dimensional accuracy of the lid member.

[0010] In the above aspect, it is preferable that a tapered or chamfered portion is formed at the boundary between the recess and the intermediate portion.

[0011] According to this aspect, the distance between the lid member and the electrode terminal can be increased by the amount of the chamfered or tapered portion formed, thereby ensuring better insulation between the lid member and the electrode terminal.

[0012] In the above aspect, it is preferable that the intermediate portion is formed over the entire circumferential direction of the outer periphery of the recess.

[0013] According to this aspect, the distance between the lid member and the electrode terminal can be increased all around the periphery of the recess, so that insulation between the lid member and the electrode terminal can be more effectively ensured.

[0014] In the above aspect, it is preferable that the intermediate portion is formed on a part of the outer periphery of the recess in the circumferential direction.

[0015] According to this aspect, it is only necessary to form the intermediate portion around only a portion of the recess, which reduces the burden and number of steps involved in molding the lid member and improves the productivity of secondary batteries. [Effects of the Invention]

[0016] According to the secondary battery of the present disclosure, insulation between the lid member and the electrode terminals can be ensured while being miniaturized. [Brief explanation of the drawings]

[0017] [Figure 1] 1 is an overall perspective view of a secondary battery according to an embodiment of the present invention; [Figure 2] 2 is a cross-sectional view of an electrode terminal and its surrounding area according to the present embodiment. FIG. [Figure 3] 10A and 10B are diagrams showing an example in which a chamfered portion is formed at the boundary between the recess and the intermediate portion; [Figure 4] 10A and 10B are diagrams showing an example in which a tapered portion is formed at the boundary between a recess and an intermediate portion; [Figure 5] FIG. 2 is a top view of the lid member of the present embodiment. [Figure 6] FIG. 10 is a top view of a modified cover member. [Figure 7] FIG. 10 is a top view of a modified cover member. [Figure 8] FIG. 1 is a cross-sectional view of an electrode terminal and its surrounding area according to a conventional technique. [Figure 9] FIG. 1 is a cross-sectional view of an electrode terminal and its surrounding area according to a conventional technique. DETAILED DESCRIPTION OF THE INVENTION

[0018] Hereinafter, an embodiment of the secondary battery of the present disclosure will be described.

[0019] <Overview of secondary batteries> 1, the secondary battery 1 of this embodiment has a case 11 with an opening 11a and a lid member 12 that seals the opening 11a. The case 11 and the lid member 12 are made of metal (for example, aluminum).

[0020] The lid member 12 is formed in a plate shape (for example, a rectangular plate shape). As shown in Figures 1 and 2, the lid member 12 has an upper surface 12a which is a surface on one side in the plate thickness direction of the lid member 12 (i.e., the up-and-down direction in Figure 2), and a lower surface 12b which is a surface on the other side in the plate thickness direction of the lid member 12. The upper surface 12a is an example of a "first surface" in the present disclosure, and the lower surface 12b is an example of a "second surface" in the present disclosure.

[0021] 1, two electrode terminals 13 are provided on the cover member 12. Of the two electrode terminals 13, one electrode terminal 13 is a positive electrode terminal and the other electrode terminal 13 is a negative electrode terminal. The two electrode terminals 13 are connected to an electrode body 14 housed in the case 11.

[0022] 2, a top surface 21 and a recess 22 are formed on the top surface 12a of the lid member 12. The recess 22 is a portion recessed downward on the top surface 12a, i.e., a portion formed at a position closer to the bottom surface 12b than the top surface 21 in the thickness direction of the lid member 12. The electrode terminal 13 is disposed across the lid member 12 from the top surface 12a to the bottom surface 12b, passing through a through hole 23 formed at the position of the recess 22.

[0023] Furthermore, a resin member 15 is disposed between the upper portion 13a of the electrode terminal 13 and the recessed portion 22 of the lid member 12. Here, the upper portion 13a of the electrode terminal 13 refers to the portion of the electrode terminal 13 that is disposed on the upper surface 12a side of the lid member 12. The resin member 15 insulates the recessed portion 22 of the lid member 12 from the upper portion 13a of the electrode terminal 13. The resin member 15 includes a bottom wall portion 15a and a side wall portion 15b, and a through hole 15c is formed in the bottom wall portion 15a. The bottom wall portion 15a and the side wall portion 15b accommodate the upper portion 13a of the electrode terminal 13, and the electrode terminal 13 passes through the through hole 15c.

[0024] Furthermore, a resin member 16 is disposed between the lower surface 12b of the cover member 12 and the lower portion 13b of the electrode terminal 13. Here, the lower portion 13b of the electrode terminal 13 refers to the portion of the electrode terminal 13 that is disposed on the lower surface 12b side of the cover member 12.

[0025] <Reducing the size of secondary batteries and ensuring insulation between the lid member and electrode terminals> 2, in this embodiment, the upper portion 13a of the electrode terminal 13 is disposed so as to fit within the area where the recess 22 is formed in the planar direction of the upper surface 12a of the lid member 12 (i.e., the left-right direction in FIG. 2). By making the electrode terminal 13 and the resin member 15 smaller than the recess 22 in this way, the height of the upper portion 13a of the electrode terminal 13 can be reduced, and the secondary battery 1 can be made smaller.

[0026] 8, in the prior art, top surface 21 is formed on top surface 12a of lid member 12 up to the vicinity of electrode terminal 13, and distance L between top surface 21 and electrode terminal 13 is short, which may result in insulative properties between lid member 12 and electrode terminal 13. Furthermore, when lid member 12 is formed by, for example, press working, stress tends to concentrate and act on outer peripheral edge 22a of recess 22, i.e., the corner at the boundary between top surface 21 and recess 22, which may result in cracks in recess 22.

[0027] 9, one prior art approach has been to increase the distance L between the top surface 21 and the electrode terminal 13 by widening the recess 22 of the cover member 12 to move the top surface 21 away from the electrode terminal 13. However, even in this case, when the cover member 12 is formed by, for example, press working, stress tends to concentrate on the outer peripheral edge 22a of the recess 22, which could cause cracks in the recess 22. Furthermore, the narrower area of ​​the top surface 21 could reduce the strength of the cover member 12.

[0028] In contrast to this, in this embodiment, as shown in Fig. 2, in addition to the top surface portion 21 and the recessed portion 22, an intermediate portion 24 is formed on the top surface 12a of the lid member 12. This intermediate portion 24 is formed at a position between the top surface portion 21 and the recessed portion 22 in the planar direction of the top surface 12a. The intermediate portion 24 is also formed at a position between the top surface portion 21 and the recessed portion 22 in the thickness direction of the lid member 12. In this way, the intermediate portion 24 is formed at a height position between the top surface portion 21 and the recessed portion 22, and a step-shaped intermediate portion 24 is formed between the top surface portion 21 and the recessed portion 22.

[0029] In this embodiment, by forming intermediate portion 24 on top surface 12a of lid member 12 in this manner, distance L1 between top surface portion 21 of lid member 12 and electrode terminal 13 can be made longer than in the prior art shown in Fig. 8. Furthermore, distance L2 between intermediate portion 24 of lid member 12 and electrode terminal 13 can be made longer by the step between top surface portion 21 and intermediate portion 24. Therefore, insulation between lid member 12 and electrode terminal 13 can be ensured.

[0030] Furthermore, when the lid member 12 is formed by, for example, press working, the stress acting on the lid member 12 is dispersed to the middle portion 24 as well, and is less likely to be concentrated on the outer peripheral edge portion 22a of the recess 22. This makes it possible to suppress the occurrence of cracks in the recess 22 and also improve the dimensional accuracy of the lid member 12.

[0031] 3, a chamfered portion 25 is formed at the boundary between the recess 22 and the intermediate portion 24. This chamfered portion 25 is a portion having a chamfered shape at the corner of the end portion on the intermediate portion 24 side at the boundary between the recess 22 and the intermediate portion 24.

[0032] 4, a tapered portion 26 may be formed at the boundary between the recess 22 and the intermediate portion 24 instead of the chamfered portion 25. The tapered portion 26 is a tapered portion (i.e., an inclined portion) that connects the recess 22 and the intermediate portion 24.

[0033] In this manner, in this embodiment, the chamfered portion 25 or the tapered portion 26 is formed at the boundary between the recess 22 and the intermediate portion 24, which increases the distance between the cover member 12 and the electrode terminal 13, thereby further ensuring insulation between the cover member 12 and the electrode terminal 13. Furthermore, by optimizing the metal flow when the cover member 12 is press-formed, the dimensional accuracy of the cover member 12 and productivity can be improved.

[0034] As shown in FIG. 5, the intermediate portion 24 is formed around the entire circumferential direction of the outer periphery of the recess 22 when the upper surface 12a of the lid member 12 is viewed from above.

[0035] This makes it possible to increase the distance between the cover member 12 and the electrode terminal 13 all around the periphery of the recess 22, thereby ensuring insulation between the cover member 12 and the electrode terminal 13 more effectively.

[0036] As a modified example, the intermediate portion 24 may be formed on a portion of the circumferential outer periphery of the recess 22 when the upper surface 12a of the lid member 12 is viewed from above. For example, as shown in Fig. 6, when the upper surface 12a of the lid member 12 is viewed from above, the intermediate portion 24 may be formed along a long side portion of the periphery of the recess 22, which is formed in a substantially rectangular shape. Alternatively, for example, as shown in Fig. 7, when the upper surface 12a of the lid member 12 is viewed from above, the intermediate portion 24 may be formed along a short side portion of the periphery of the recess 22, which is formed in a substantially rectangular shape.

[0037] In this way, it is only necessary to form the intermediate portion 24 on only a part of the periphery of the recess 22, so the burden and number of steps required to form the lid member 12 can be reduced, and the productivity of the secondary battery 1 can be improved.

[0038] It should be noted that the above-described embodiments are merely examples and do not limit the present disclosure in any way. It goes without saying that various improvements and modifications are possible within the scope of the gist of the present disclosure. [Explanation of symbols]

[0039] 1 Secondary battery 11 cases 11a opening 12 Lid member 12a Top side 12b Bottom side 13 Electrode terminal 13a Upper 13b lower part 14 Electrode body 15 Resin parts 15a Bottom wall 15b Side wall part 15c through hole 16 Resin parts 21 Top section 22 recess 22a Outer edge 23 through hole 24 Middle section 25 Chamfered section 26 Tapered section L,L1,L2 distance

Claims

1. a case having an opening and accommodating the electrode assembly; a plate-shaped lid member that seals the opening; an electrode terminal provided on the cover member and connected to the electrode body; and The lid member includes a first surface which is a surface on one side in a plate thickness direction of the lid member, and a second surface which is a surface on the other side in the plate thickness direction of the lid member, a top surface portion and a recess portion formed on the first surface of the lid member at a position closer to the second surface than the top surface portion in a plate thickness direction of the lid member, the electrode terminal is disposed through a through hole formed in the lid member at the position of the recess, from the first surface side to the second surface side of the lid member; a portion of the electrode terminal that is disposed on the first surface side of the lid member is disposed within a range in which the recess is formed in a planar direction of the first surface, a resin member is disposed between the recess and a portion of the electrode terminal that is disposed on the first surface side of the lid member; an intermediate portion is formed on the first surface of the lid member at a position between the top surface portion and the recessed portion in a surface direction of the first surface, and at a position between the top surface portion and the recessed portion in a plate thickness direction of the lid member; the intermediate portion is formed at a position outside a portion of the electrode terminal that is disposed on the first surface side with respect to the lid member in a planar direction of the first surface; A secondary battery characterized by:

2. 2. The secondary battery of claim 1, a tapered or chamfered portion is formed at the boundary between the recess and the intermediate portion; A secondary battery characterized by:

3. 3. The secondary battery of claim 1, the intermediate portion is formed over the entire circumferential direction of the outer periphery of the recess; A secondary battery characterized by:

4. 3. The secondary battery of claim 1, the intermediate portion is formed on a portion of the outer periphery of the recess in the circumferential direction; A secondary battery characterized by:

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