Battery pack

Abstract

To provide a technique for suppressing contact between an upper case and parts inside a pack in a battery pack.SOLUTION: The battery pack includes a plurality of batteries, a case having a case body that partitions a compartment that accommodates the plurality of batteries and a flange portion that extends outward from the top of the case body, and a seal member that seals the flange portion. The case has a lower case that has a lower case body with a concave shape that constitutes the case body and a lower flange that constitutes the flange portion and an upper case that covers an opening and has an upper case body that constitutes the case body and an upper flange that constitutes the flange portion. The lower flange and upper flange each have an end portion where the seal member is arranged and an opposing unit that connects the end portion and the case body and extends outward from the top portion. The end portion is slanted with respect to the opposing unit.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present disclosure relates to a battery pack. [Background technology]

[0002] Conventionally, there are known battery packs that are mounted on vehicles, etc. For example, Patent Document 1 discloses a battery pack that includes a secondary battery housed in the battery pack, an upper flange provided on an upper case, a lower flange provided on a lower case, and a seal member disposed between the upper flange and the lower flange. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2022-165836 Summary of the Invention [Problem to be solved by the invention]

[0004] In a battery pack, if the pressure inside the battery pack increases due to, for example, a large amount of gas containing hydrogen being generated from the secondary battery, the pressure inside the battery pack may cause the upper case to deform, bulging upward. In this case, part of the upper case body that forms the housing chamber that houses the battery pack may be displaced inward. This may cause interference between the upper case and internal components arranged inside the battery pack. [Means for solving the problem]

[0005] The present disclosure can be realized in the following forms.

[0006] (1) According to a first aspect of the present disclosure, there is provided a battery pack including: a case body defining a chamber for accommodating a plurality of batteries; a case having a flange portion extending outward from an upper portion of the case body; and a seal member sealing the flange portion, wherein the case includes a lower case having an opening formed at an upper end portion, the lower case having a concave-shaped lower case body constituting the case body and a lower flange constituting the flange portion; and an upper case covering the opening, the upper case having an upper case body constituting the case body and an upper flange constituting the flange portion, the lower flange and the upper flange each having an end portion where the seal member is disposed and an opposing portion connecting the end portion to the case body and extending outward from the upper portion, the end portion being inclined relative to the opposing portion. According to this configuration, the flange portion has an opposing portion that projects outward from the case body, so even if the pressure inside the battery pack increases and the upper case deforms so as to bulge upward, the upper case body can be prevented from deforming inward into the storage chamber, thereby reducing the possibility of interference between the upper case and internal components of the pack. (2) In the above embodiment, the end portion may have a boundary portion that is a boundary between the end portion and the opposing portion, and may be bent at the boundary portion so that the end portion is inclined with respect to the opposing portion. According to this configuration, when the pressure inside the battery pack increases and the upper case deforms by expanding upward, the upper case deforms upward starting from the boundary, thereby reducing the possibility of interference between the upper case and internal components of the pack. (3) In the above embodiment, the end portion may extend from the opposing portion toward a side where the bottom of the lower case body is located, and may be inclined with respect to the opposing portion. According to this configuration, the end portion is located lower than the opposing portion, i.e., closer to the bottom of the lower case body, thereby preventing the case from becoming too tall. (4) In the above embodiment, the end portion may be bent at a right angle to the facing portion, and may be inclined relative to the facing portion. According to this configuration, the end portion is bent at a right angle to the opposing portion, thereby making it possible to prevent the size of the case in a direction perpendicular to the height direction from increasing. The present disclosure can be realized in various forms, and in addition to the forms described above, can also be realized in the form of a battery pack manufacturing method, etc. [Brief explanation of the drawings]

[0007] [Figure 1] A view of the battery pack from above. [Figure 2] FIG. 2 is a schematic cross-sectional view of the battery pack taken along line II-II. [Figure 3] 10 is an explanatory diagram showing deformation of an upper case when the internal pressure of a conventional battery pack increases. [Figure 4] 5A and 5B are explanatory diagrams showing deformation of the upper case when the internal pressure increases in the first embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0008] A. First embodiment: FIG. 1 is a view of a battery pack 1 as seen from above. The battery pack 1 includes a case 9, multiple modules 3 arranged in the case 9, and a bus bar 5 that electrically connects the multiple modules 3. The case 9 has a case body 90 that defines a storage chamber 8 that houses the multiple modules 3. Each of the multiple modules 3 includes multiple secondary batteries 4. The secondary batteries 4 are, for example, lithium-ion batteries. The bus bar 5 is a pack internal component and a high-voltage component. The battery pack 1 also includes a pressure release valve 7 formed in the case body 90. Note that the secondary batteries 4 are not limited to lithium-ion batteries and may be other batteries such as nickel-metal hydride batteries. The pressure release valve 7 is provided at any position in an upper case body 210 of the case body 90, which will be described later.

[0009] Fig. 2 is a schematic diagram showing a cross section taken along line II-II of the battery pack 1 in Fig. 1. In addition to a case main body 90, the case 9 has a flange portion 30 that protrudes outward from the top of the case main body 90. The case 9 has a lower case 100 and an upper case 200. The lower case 100 and the upper case 200 are made of metal.

[0010] The lower case 100 has an opening formed at its upper end. The lower case 100 has a concave lower case main body 110 that constitutes the case main body 90, and a lower flange 120 that constitutes the flange portion 30. The lower flange 120 protrudes outward from the lower case main body 110. In this embodiment, the module 3 is fixed to the lower case main body 110 using a bracket and adhesive (not shown).

[0011] Upper case 200 is shaped to cover the opening of lower case 100. Upper case 200 has an upper case main body 210 that constitutes case main body 90, and an upper flange 220 that constitutes flange portion 30. Upper flange 220 protrudes outward from upper case main body 210 and faces lower flange 120.

[0012] The battery pack 1 further includes a seal member 10 that seals the flange portion 30. The seal member 10 seals the gap between the lower case 100 and the upper case 200, thereby hermetically sealing the battery pack 1. More specifically, the seal member 10 seals the gap between the lower flange 120 and the upper flange 220. The seal member 10 is, for example, a gasket. Note that the seal member 10 is not limited to a gasket and may be an adhesive or the like.

[0013] The flange portion 30 includes an end portion 22 where the seal member 10 is disposed, an opposing portion 24 that connects the end portion 22 and the case body 90 and protrudes outward from the upper portion of the case body 90, and a boundary portion 26 that is the boundary between the end portion 22 and the opposing portion 24. The boundary portion 26 is an area where the flange portion 30 bends.

[0014] The lower flange 120 includes a lower flange end portion 122 that constitutes the end portion 22, a lower flange opposing portion 124 that constitutes the opposing portion 24, and a lower flange boundary portion 126 that constitutes the boundary portion 26.

[0015] The upper flange 220 includes an upper flange end portion 222 that constitutes the end portion 22 , an upper flange opposing portion 224 that constitutes the opposing portion 24 , and an upper flange boundary portion 226 that constitutes the boundary portion 26 .

[0016] The lower flange end portion 122 and the upper flange end portion 222 are parallel to each other. The lower flange opposing portion 124 and the upper flange opposing portion 224 are also parallel to each other.

[0017] In this embodiment, the facing portion 24 extends in a direction perpendicular to the direction in which the bottom of the lower case body 110 and the upper case body 210 face each other, i.e., perpendicular to the up-down direction of the battery pack 1. The perpendicular direction is the horizontal direction when the battery pack 1 is placed on a horizontal surface. The end portion 22 extends from the facing portion 24 toward the side where the bottom of the lower case body 110 is located. Furthermore, the flange portion 30 is bent at a right angle at the boundary portion 26, and the end portion 22 is inclined at a right angle relative to the facing portion 24. Here, the "right angle" corresponds to an angle within the range of 90±10°.

[0018] In this embodiment, the bus bar 5 is located between the side surface of the case body 90 (specifically, the side surface of the lower case body 110) and the module 3. In this embodiment, in the height direction of the battery pack 1, a portion of the bus bar 5 is at a height position overlapping with the upper part of the module 3. The bus bar 5 is also disposed at a predetermined distance from the bottom of the lower case body 110.

[0019] 3 is an explanatory diagram showing deformation of an upper case 200t when the internal pressure of a conventional battery pack 1t increases. The conventional flange portion 30t of the battery pack 1t is not located at the top of the case body 90t, but is located in the middle of the case body 90t.

[0020] The flange portion 30t consists of an end portion 22t and an opposing portion 24t, and does not include the boundary portion 26. The lower flange 120t includes a lower flange end portion 122t that constitutes the end portion 22t, and a lower flange opposing portion 124t that constitutes the opposing portion 24t. The upper flange 220t includes an upper flange end portion 222t that constitutes the end portion 22t, and an upper flange opposing portion 224t that constitutes the opposing portion 24t. The upper case main body 210t includes a top portion 211t and a side portion 212t. The other configurations are the same as those in FIG. 2.

[0021] In FIG. 3, for example, if a secondary battery 4 constituting the module 3 short-circuits, a large amount of hydrogen-containing gas may be generated inside the battery pack 1t in a short period of time. In this case, even if the battery pack 1t is equipped with a pressure release valve 7, hydrogen gas and other gases may accumulate inside the battery pack 1t, exceeding the release capacity of the pressure release valve 7. In FIG. 3, because hydrogen-containing gas is lighter than air, it accumulates in the upper space S1 inside the housing chamber 8t. As a result, when the internal pressure of the battery pack 1t exceeds a specified value, the top portion 211t of the upper case main body 210t deforms upward. Meanwhile, the side portion 212t of the upper case main body 210t is affected by the deformation of the top portion 211t and deforms in a direction approaching the bus bar 5. This may cause interference between the upper case 200t and the bus bar 5, resulting in a short circuit.

[0022] Fig. 4 is an explanatory diagram showing deformation of upper case 200 when internal pressure rises in this embodiment. The configuration of a part of case main body 90 and flange portion 30 in Fig. 4 is the same as that in Fig. 2. Note that the bending point of upper flange boundary portion 226 that constitutes boundary portion 26 is referred to as bending point a.

[0023] In FIG. 4 , for example, if a secondary battery 4 constituting the module 3 short-circuits, a large amount of gas containing hydrogen is generated inside the battery pack 1 in a short period of time. As a result, hydrogen gas and other gases exceed the release capacity of the pressure release valve 7 and accumulate in the upper space S2 of the storage chamber 8. When the internal pressure of the battery pack 1 exceeds a predetermined value due to the generation of gas, the upper case main body 210 deforms upward. At this time, the upper case 200 deforms upward from a bending point a of the upper flange boundary portion 226 constituting the boundary portion 26 of the upper flange 220 located on the outer side of the upper case main body 210. This prevents the upper case main body 210 from deforming inward of the storage chamber 8, thereby reducing the possibility of interference between the upper case 200 and the bus bar 5. This prevents a short circuit between the upper case 200 and the bus bar 5.

[0024] As described above, in the battery pack 1 of this embodiment, as shown in Fig. 2, the flange portion 30 has the opposing portion 24 that protrudes outward from the top of the case body 90. Therefore, even if the pressure inside the battery pack 1 increases and the upper case 200 deforms so as to bulge upward, the upper case body 210 can be prevented from deforming inwardly of the accommodating chamber 8. This reduces the possibility of interference between the upper case 200 and the bus bar 5. Therefore, a short circuit between the upper case 200 and the bus bar 5 can be prevented.

[0025] In addition, in the battery pack 1 of this embodiment, the flange portion 30 is bent at a right angle at the boundary portion 26, so that the opposing portion 24 and the end portion 22 are inclined at a right angle. This prevents the height of the case 9 from increasing. Furthermore, it prevents the distance from the case main body 90 to the end portion 22, that is, the dimension in the direction perpendicular to the case main body 90, from increasing. This allows a more compact battery pack 1 to be designed.

[0026] B. Other Embodiments: (B1) In the first embodiment described above, the battery pack 1 is provided with the pressure release valve 7. In contrast, the battery pack 1 does not necessarily have to be provided with the pressure release valve 7.

[0027] (B2) In the first embodiment described above, the in-pack component is the bus bar 5. However, the in-pack component does not have to be the bus bar 5.

[0028] (B3) In the first embodiment described above, the flange portion 30 is bent at a right angle at the boundary portion 26, and the opposing portion 24 and the end portion 22 are inclined at a right angle. In contrast, the flange portion 30 does not have to be bent at a right angle at the boundary portion 26, and the opposing portion 24 and the end portion 22 do not have to be inclined at a right angle.

[0029] The present disclosure is not limited to the above-described embodiments and can be realized in various configurations without departing from the spirit thereof. For example, the technical features of the embodiments corresponding to the technical features in each aspect described in the Summary of the Invention section can be appropriately replaced or combined to solve some or all of the above-described problems or achieve some or all of the above-described effects. Furthermore, if a technical feature is not described as essential in this specification, it can be appropriately deleted. [Explanation of symbols]

[0030] 1,1t...battery pack, 3...module, 4...secondary battery, 5...bus bar, 7...pressure release valve, 8...accommodation chamber, 9...case, 10...sealing member, 22,22t...end, 24,24t...opposing portion, 26...boundary portion, 30,30t...flange portion, 90,90t...case main body, 100...lower case, 110...lower case main body, 120,120t...lower flange, 122,122t...lower Flange end, 124, 124t...lower flange opposing portion, 126...lower flange boundary portion, 200, 200t...upper case, 210, 210t...upper case main body, 211t...top portion, 212t...side portion, 220, 220t...upper flange, 222, 222t...upper flange end, 224, 224t...upper flange opposing portion, 226...upper flange boundary portion

Claims

1. A battery pack, Multiple batteries and a case having a case body defining a chamber for accommodating the plurality of batteries and a flange portion extending outward from an upper portion of the case body; a seal member that seals the flange portion, The case is a lower case having an opening formed at an upper end thereof, the lower case having a concave-shaped lower case main body constituting the case main body, and a lower flange constituting the flange portion; an upper case covering the opening, the upper case having an upper case main body constituting the case main body and an upper flange constituting the flange portion; The lower flange and the upper flange each include: an end portion where the sealing member is disposed; an opposing portion that connects the end portion and the case main body and that protrudes outward from the upper portion, The end portion is inclined relative to the opposing portion.

2. 2. The battery pack according to claim 1, a boundary portion that is a boundary between the end portion and the opposing portion, The battery pack is bent at the boundary portion, so that the end portion is inclined relative to the opposing portion.

3. 2. The battery pack according to claim 1, The end portion extends from the opposing portion toward a side where the bottom of the lower case body is located, and is inclined relative to the opposing portion.

4. The battery pack according to any one of claims 1 to 3, The end portion is bent at a right angle to the opposing portion and is inclined relative to the opposing portion.

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