Battery

Abstract

Provided is a battery in which deterioration in sealing performance due to deterioration of compression of a gasket over time is suppressed. The cover member has, around the through-hole, a first convex portion protruding toward the inside of the exterior body, and a first concave portion following the first convex portion toward the through-hole side. The flange portion of the current collection terminal has, around the shaft portion, a second protruding portion protruding toward the cover member side at a position facing the first protruding portion, and a second recessed portion formed at a position facing the first recessed portion and following the second protruding portion toward the shaft portion side. The flange portion of the gasket is sandwiched between the flange portion and the cover member (exterior body) and deforms (compressively deforms) by bearing a compressive load. A space is formed between the flange portion and the first recessed portion and between the flange portion and the second recessed portion at a position where the first recessed portion of the cover member and the second recessed portion of the flange portion face each other, so that a compressive load is not received.

Description

Technical Field

[0001] This disclosure relates to batteries. Background Technology

[0002] Japanese Patent Application Publication No. 2011-243559 (Patent Document 1) discloses a secondary battery having a sealing member (sealing gasket) held between a battery cover and an external lead-out terminal (connecting pin). In this Patent Document 1, by providing a first protrusion on the surface of the battery cover or connecting pin that is pressed against the sealing gasket, and further providing a second protrusion on its inner side, leakage is prevented over a long period of time.

[0003] Existing technical documents

[0004] Patent documents

[0005] Patent Document 1: Japanese Patent Application Publication No. 2011-243559 Summary of the Invention

[0006] The problem that the invention aims to solve

[0007] In Patent Document 1, the sealing portion of the gasket surrounded between the first and second protrusions does not flow, thus increasing the pressure on the gasket and slowing down the rate of pressure reduction, thereby preventing leakage over a long period. However, since the gasket (sealing member) is compressed (pressed) throughout, the resilience (elastic force) of the gasket (sealing member) decreases due to years of compression deterioration, potentially worsening the sealing performance.

[0008] The purpose of this disclosure is to suppress the deterioration of sealing performance caused by the compression and deterioration of the gasket over the years.

[0009] Methods for solving problems

[0010] The battery disclosed herein includes a battery element, an outer casing, current collector terminals, and a sealing gasket. The outer casing houses the battery element. The current collector terminals include a flange portion disposed inside the outer casing and a shaft portion that passes through a through hole formed in the outer casing and protrudes to the outside of the outer casing. The sealing gasket includes a flange portion disposed between the flange portion and the outer casing, and a cylindrical portion disposed between the inner circumferential surface of the through hole and the shaft portion. The outer casing has a first protrusion protruding toward the interior of the outer casing and a first recess continuing toward the through hole side after the first protrusion around the through hole. The flange portion has a second protrusion protruding toward the outer casing side at a position opposite to the first protrusion and a second recess formed at a position opposite to the first recess and continuing toward the shaft side after the second protrusion around the shaft portion.

[0011] According to this configuration, the flange portion of the sealing gasket is clamped by the flange portion and the outer body and deformed under compressive load (compression deformation). At positions where the first and second recesses face each other, spaces are formed between the flange portion and the first recess, and between the flange portion and the second recess, thus preventing them from bearing compressive load. Since the portions of the flange portion that do not bear compressive load are not compressed, the reduction in resilience caused by years of compression degradation can be suppressed. Therefore, at the connection points between the first and first recesses, and between the second and second recesses, the reduction in resilience caused by years of compression degradation can be suppressed, thereby preventing deterioration of the sealing performance.

[0012] Invention Effects

[0013] According to this disclosure, it is possible to suppress the deterioration of sealing performance caused by the compression and deterioration of the sealing gasket over the years. Attached Figure Description

[0014] Figure 1 This is a cross-sectional view showing the internal structure of the sealed battery according to this embodiment.

[0015] Figure 2 yes Figure 1 An enlarged view of region II shown.

[0016] Figure 3 yes Figure 2 An enlarged view of region III shown.

[0017] Figure 4 It is before the nut is tightened and connected to the shaft. Figure 2 An enlarged view of region III shown.

[0018] Figure 5 It is a diagram illustrating the behavior associated with the expansion and contraction of the gasket.

[0019] Explanation of reference numerals in the attached figures

[0020] 13 Through hole, 20 Battery element, 24 Enclosure, 27 Sealing gasket, 28 Cylindrical part, 29 Flange part, 30 Outer body, 31 Housing, 32 Cover component, 32a First protrusion, 32b First recess, 33 Shaft part, 34 Flange part, 34a Second protrusion, 34b Second recess, 35 Opposing surface, 36 Opposing surface, 40 External terminal, 45 Current collector terminal, 46 Current collector terminal component, 47 Conductive plate, 48 Current collector plate, 50 Insulator, 51 Nut, 100 Sealed battery. Detailed Implementation

[0021] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. Furthermore, identical or equivalent parts in the drawings will be labeled with the same reference numerals, and their descriptions will not be repeated. The dimensional relationships (length, width, thickness, etc.) in the drawings do not reflect actual dimensional relationships.

[0022] Figure 1 This is a cross-sectional view showing the internal structure of the sealed battery 100 according to this embodiment. The sealed battery 100 can be used as a battery pack, for example, by combining multiple units in series. The sealed battery 100 includes a battery element 20, an outer casing 30, a conductive plate 47, external terminals 40, and a current collector terminal member 46. The battery element 20 is constructed by stacking positive and negative electrode plates separated by a separator. The battery element 20 may also be an electrode body made of a wound body.

[0023] The outer casing 30 internally houses the battery element 20. The outer casing 30 has a housing 31 and a cover member 32. The housing 31 is a generally rectangular box shape that opens in one direction and has a bottom 60. The battery element 20 is housed together with the electrolyte inside the housing 31.

[0024] The cover member 32 has a flat plate shape, which has a generally rectangular plan view. The cover member 32 is disposed at an opening formed in the housing 31. The cover member 32 is provided to block the opening in the housing 31. A through hole 13 is formed in the cover member 32. The cover member 32 and the housing 31 form a sealed space for accommodating the battery element 20. The cover member 32 and the housing 31 are made of a metallic material such as aluminum.

[0025] A conductive plate 47 is disposed on the exterior of the outer casing 30. The conductive plate 47 is a conductive plate-shaped member formed in the shape of a crank when viewed from the front. External terminals 40 are disposed on the exterior of the outer casing 30. Two external terminals 40 are provided in the sealed battery 100. One is an external terminal 40 for the positive electrode, and the other is an external terminal 40 for the negative electrode. The external terminals 40 are disposed through the conductive plate 47 and are electrically connected to the conductive plate 47.

[0026] The current collector terminal component 46 includes a current collector plate 48 and a current collector terminal 45. The current collector plate 48 is disposed inside the housing 31 and is electrically connected to the electrodes of the battery element 20. The current collector plate 48 is assembled integrally with the current collector terminal 45. The current collector plate 48 and the current collector terminal 45 are electrically connected.

[0027] The current collector terminal 45 is connected to the conductive plate 47 on the outside of the outer casing 30. The current collector terminal 45 is provided through the through hole 13 of the cover member 32 and the conductive plate 47. The current collector terminal 45 extends from the inside of the outer casing 30 (sealed battery 100) to the outside.

[0028] Figure 2 yes Figure 1 An enlarged view of region II is shown. The current collector terminal 45 has a shaft portion 33 and a flange portion (current collector head) 34. In this embodiment, the shaft portion 33 has a cylindrical shape.

[0029] The shaft portion 33 protrudes from the flange portion 34. The shaft portion 33 passes through the through hole 13 of the cover member 32 and protrudes to the outside of the outer body 30. The shaft portion 33 is provided outside the outer body 30 in such a way that it passes through the conductive plate 47 and the insulator 50. A threaded portion 33a is formed at the end of the shaft portion 33 that protrudes to the outside of the outer body 30.

[0030] Flange 34 is disposed inside housing 31. Flange 34 has a flange shape extending radially outward from the root of shaft 33. The diameter of flange 34 is larger than the diameter of through hole 13. Flange 34 has opposing surface 35 opposite to gasket 27. Opposing surface 35 abuts against gasket 27.

[0031] The sealing gasket 27 is electrically insulating and is interposed between the cover member 32 and the current collector terminal 45. The sealing gasket 27 serves as a sealing material between the cover member 32 and the current collector terminal 45. Thus, the interior of the outer casing 30 is sealed. The sealing gasket 27 can be formed, for example, from an elastic resin or rubber material such as PFA (perfluoroalkoxyfluoropolymer) or EPDM (ethylene propylene diene monomer rubber).

[0032] The sealing gasket 27 has a cylindrical portion 28, a flange portion 29, and a surrounding portion 24. The cylindrical portion 28 has a hollow cylindrical shape. The cylindrical portion 28 protrudes from the flange portion 29. The cylindrical portion 28 is inserted into the through hole 13 and is disposed between the inner circumferential surface of the through hole 13 and the shaft portion 33.

[0033] The flange portion 29 has a flange shape that extends radially outward from the cylindrical portion 28. The flange portion 29 is disposed between the cover member 32 and the flange portion 34. The flange portion 29 is fixed between the cover member 32 and the current collector terminal 45 in a state of compression deformation.

[0034] The surrounding portion 24 has a hollow cylindrical shape. The surrounding portion 24 protrudes from the outer periphery of the flange portion 29 toward the bottom 60 and is disposed around the flange portion 34.

[0035] An insulator 50 is disposed on the outside of the outer casing 30 and between the cover member 32 and the conductive plate 47. The insulator 50 is disposed between the cover member 32 and... Figure 1 The external terminals 40 are shown. An insulator 50, formed of insulating material, electrically insulates the cover member 32 from the external terminals 40 and the conductive plate 47. The conductive plate 47 is mounted on the insulator 50. (As shown) Figure 1 As shown, the external terminal 40 and the current collector terminal 46 are electrically connected via a conductive plate 47.

[0036] Figure 3 yes Figure 2 An enlarged view of region III is shown. (Refer to...) Figure 3The cover member 32 has a facing surface 36 opposite to the sealing gasket 27. A first protrusion 32a is formed on the facing surface 36 of the cover member 32, protruding toward the interior of the outer body 30. The first protrusion 32a is formed around the through hole 13. On the cover member 32, a first recess 32b is formed on the side of the through hole 13, following the first protrusion 32a (continuously with the first protrusion 32a). The first recess 32b is recessed toward the exterior of the outer body 30. The first recess 32b is formed around the through hole 13. The cover member 32 has a first protrusion 32a and a first recess 32b on the facing surface 36.

[0037] The flange portion 34 of the current collector terminal 45 has a second protrusion 34a and a second recess 34b on the surface (opposing surface 35) opposite to the flange portion 29 of the sealing gasket 27. The second protrusion 34a is positioned opposite to the first protrusion 32a and protrudes outward toward the outer surface of the outer casing 30. The second recess 34b is positioned opposite to the first recess 32b and recesses inward toward the inner surface of the outer casing 30. The second recess 34b is formed on the shaft portion 33 side, following the second protrusion 34a (continuously with the second protrusion 34a). The second protrusion 34a and the second recess 34b are formed around the shaft portion 33.

[0038] Reference Figure 2 The nut 51 is screwed into the threaded portion 33a of the shaft portion 33. The nut 51 has a flange 51a with a diameter larger than that of the shaft portion 33. The flange 51a is in contact with the conductive plate 47.

[0039] By screwing the nut 51 onto the shaft portion 33, the flange 51a presses down on the conductive plate 47. By pressing the conductive plate 47 down on the flange 51a, the gasket 27, the cover member 32, the insulator 50, and the conductive plate 47 are clamped by the nut 51 and the flange portion 34. As a result, the gasket 27 is compressed, and the flange portion 29 is pressed tightly against the opposing surface 35.

[0040] Figure 4 It is before the nut 51 is fastened to the shaft 33. Figure 2 An enlarged view of region III is shown. The flange 29 of the gasket 27 has a substantially uniform thickness (wall thickness) before compression. The cylindrical portion 28 is inserted around the shaft portion 33. The surrounding portion 24 covers a portion of the periphery of the flange portion 34.

[0041] When nut 51 is tightened to the shaft 33, due to compressive load, such as Figure 3As shown, the flange portion 29 of the sealing gasket 27 is compressed and deformed (compression deformation). This forms a sealing surface between the cover member 32 and the flange portion 29, and between the flange portion 34 and the flange portion 29. In the region where the first protrusion 32a and the second protrusion 34a face each other, the amount of compression (deformation) of the flange portion 29 (sealing gasket 27) increases. In the first recess 32b and the second recess 34b, a portion of the flange portion 29 is not compressed (no compressive load is applied), and a space C is formed between the flange portion 29 and the cover member 32 (first recess 32b), and between the flange portion 29 and the flange portion 34 (second recess 34b).

[0042] By compressing the sealing gasket 27 (flange 29), the internal and external sealing of the outer casing 30 can be ensured. In the compressed portion of the sealing gasket 27, due to years of compression deterioration, the resilience (elastic force) of the sealing gasket decreases, and the sealing performance sometimes deteriorates.

[0043] The portion of flange 29 that does not bear compressive load (the portion facing space C) is not compressed, thus suppressing the decrease in resilience caused by years of compression degradation. Therefore, at the connection between the first protrusion 32a and the first recess 32b (corner: refer to the area K1 enclosed by the dashed line), and at the connection between the second protrusion 34a and the second recess 34b (corner: refer to the area K2 enclosed by the dashed line), it is difficult for the resilience caused by years of compression degradation to occur, and the resilience (elastic force) can be maintained even after years, thus suppressing the deterioration of the seal.

[0044] The outer casing 30 (cover member 32) is formed of a metal material such as aluminum. The current collector terminal 45 (flange portion 34) is formed of a conductive metal material such as aluminum alloy or copper alloy. The flange portion 29 (sealing gasket 27) is formed of a resin material such as PFA or EPDM, or a rubber material. Therefore, the coefficients of thermal expansion (linear expansion coefficients) of the cover member 32 and the flange portion 29 are different, and the coefficients of thermal expansion (linear expansion coefficients) of the flange portion 34 and the flange portion 29 are also different. (Generally, the coefficient of thermal expansion of metal materials is greater than that of resin materials.) The battery (sealed battery 100) generates heat during charging and discharging, and the temperatures of the cover member 32, the current collector terminal 45, and the sealing gasket 27 rise. As the temperature rises, the expansion amount of the cover member 32 differs from that of the sealing gasket 27. As the temperature rises, the expansion amount of the flange portion 34 differs from that of the sealing gasket 27. Furthermore, when the temperature decreases (during cooling), the shrinkage of the cover member 32 differs from that of the sealing gasket 27, and the shrinkage of the flange portion 34 also differs from that of the sealing gasket 27. Due to these differences, the sealing surfaces of the cover member 32 and the flange portion 29, as well as the sealing surfaces of the flange portion 34 and the flange portion 29, may shift, potentially deteriorating the sealing performance.

[0045] Figure 5This diagram illustrates the actions associated with the expansion and contraction of the sealing gasket 27. (See diagram for example.) Figure 5 As indicated by arrow (A), when the flange portion 29 shifts relative to the cover member 32 and the flange portion 34 towards the shaft portion 33 due to the expansion and contraction of the sealing gasket 27, the flange portion 29 is pressed against the side surface S1 of the first protrusion 32a and the side surface S2 of the second protrusion 34a, thereby suppressing the deterioration of the sealing performance. Figure 5 As shown in (B), when the flange portion 29 is offset relative to the cover member 32 and the flange portion 34 in the opposite direction to the shaft portion 33 due to the expansion and contraction of the sealing gasket 27, the flange portion 29 is pressed against the side surface S3 of the first protrusion 32a and the side surface S4 of the second protrusion 34a, which can suppress the deterioration of the sealing performance.

[0046] According to this embodiment, the cover member 32 has a first protrusion 32a protruding toward the interior of the outer casing 30 (sealed battery 100) and a first recess 32b continuing toward the through hole 13 after the first protrusion 32a. The flange portion 34 of the current collector terminal 45 has a second protrusion 34a protruding toward the cover member 32 (outer casing 30) at a position opposite to the first protrusion 32a and a second recess 34b formed at a position opposite to the first recess 32b and continuing toward the shaft portion 33 after the second protrusion 34a. The flange portion 29 of the sealing gasket 27 is clamped by the flange portion 34 and the cover member 32 (outer casing 30) and deformed by compressive load (compression deformation). At the positions where the first recess 32b of the cover member 32 and the second recess 34b of the flange portion 34 face each other, spaces C are formed between the flange portion 29 and the first recess 32b, and between the flange portion 29 and the second recess 34b, thus preventing them from being subjected to compressive loads. The portion of the flange portion 29 that does not bear compressive loads is not compressed, thereby suppressing the reduction in resilience caused by years of compression degradation. Therefore, at the connection K1 between the first protrusion 32a and the first recess 32b, and at the connection K2 between the second protrusion and the second recess, the reduction in resilience caused by years of compression degradation can be suppressed, thus preventing the deterioration of the sealing performance.

[0047] In this embodiment, when the temperature of the sealed battery 100 rises or cools down, even if the sealing surfaces of the cover member 32 and the flange portion 29 and the flange portion 34 and the flange portion 29 shift due to the expansion and contraction of the sealing gasket 27, the flange portion 29 is pressed against the side surface S1 of the first protrusion 32a and the side surface S2 of the second protrusion 34a, or the side surface S3 of the first protrusion 32a and the side surface S4 of the second protrusion 34a, thereby suppressing the deterioration of the sealing performance.

[0048] In the above embodiment, the nut 51 is fastened (screwed) to the threaded portion 33a formed in the shaft portion 33 of the current collector terminal 45, and the tightening torque of the nut 51 applies a compressive load to the sealing gasket 27 (flange portion 29). However, a compressive load can also be applied to the sealing gasket 27 by riveting or other methods to achieve a tight fit.

[0049] The embodiments disclosed herein should be considered illustrative rather than restrictive in all respects. The scope of this disclosure is defined not by the description of the embodiments above, but by the claims, and is intended to include all modifications within the meaning and scope equivalent to the claims.

Claims

1. A battery comprising: Battery components; The outer casing houses the battery element; The current collector terminal includes a flange portion disposed inside the outer casing and a shaft portion passing through a through hole formed in the outer casing and protruding to the outside of the outer casing; and The sealing gasket includes a flange portion disposed between the flange portion and the outer body, and a cylindrical portion disposed between the inner circumferential surface of the through hole and the shaft portion. The outer casing has a first protrusion protruding toward the interior of the outer casing around the through hole and a first recess continuing toward the through hole side after the first protrusion. The flange portion has a second protrusion protruding toward the outer body side at a position opposite to the first protrusion and a second recess formed at a position opposite to the first recess and continuing toward the shaft side after the second protrusion.

2. The battery according to claim 1, The flange portion of the sealing gasket is fixed in a compressed and deformed state between the outer body and the flange portion, and has an uncompressible portion at the position opposite to the first recess and the second recess.

3. The battery according to claim 1 or 2, The coefficient of thermal expansion of the current collector terminal is different from that of the sealing gasket.

4. The battery according to claim 3, The outer casing includes a housing having an opening and accommodating the battery element, and a cover member that seals the opening. The through hole is formed in the cover member. The coefficient of thermal expansion of the current collector terminal is different from that of the sealing gasket.

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