Battery pack

Abstract

A battery pack (1) of the present application includes a plurality of battery cells (100) arranged along a first direction, and a case (200) having an internal space (230) that houses the plurality of battery cells. The case (200) includes a first member (210), a second member (220) that forms the internal space (230) together with the first member (210), and a seal portion (240) that seals a joint portion of the first member (210) and the second member (220). The first member (210) has a first portion (211) that abuts against the seal portion (240). The second member (220) has a second portion (220) that opposes the first portion (211) across the seal portion (240). When an expansion pressure of the internal space (230) acts on the case (200), a force in a shearing direction acts on the seal portion (240) that is sandwiched by the first portion (210) and the second portion (220).

Description

Technical Field

[0001] This technology relates to battery packs. Background Technology

[0002] There have been ongoing efforts to improve the water resistance of battery packs. For example, Japanese Patent Application Publication No. 2011-100619 discloses a battery pack that includes a sealing component, which is clamped at the joint surface between the outer casing and the cover plate to seal the joint interface in a waterproof state. Summary of the Invention

[0003] Previous designs assumed the subsequent disassembly of the casing. Furthermore, there was room for improvement in the casing's resistance to expansion pressure. The objective of this technology is to provide a battery pack with greater resistance to expansion pressure relative to the casing.

[0004] The battery pack of this technology includes: a plurality of battery cells arranged along a first direction; and a housing having an internal space for accommodating the plurality of battery cells. The housing includes a first component, a second component forming the internal space together with the first component, and a sealing portion sealing the joint between the first component and the second component. The first component has a first portion abutting against the sealing portion. The second component has a second portion opposing the first portion across the sealing portion. When the expansion pressure of the internal space acts on the housing, a shear force acts on the sealing portion clamped by the first portion and the second portion.

[0005] The above and other objects, features, aspects and advantages of the present invention will become clear from the following detailed description relating to the present invention, taken in conjunction with the accompanying drawings. Attached Figure Description

[0006] Figure 1 It is an exploded 3D diagram showing the structure of the battery pack.

[0007] Figure 2 This is a diagram showing the battery cells included in a battery module.

[0008] Figure 3 This is a diagram showing the simplified shape of the casing of the battery pack involved in Comparative Example 1.

[0009] Figure 4 It means Figure 3 A cross-sectional view of the shape of section IV.

[0010] Figure 5 This is a diagram showing the simplified shape of the casing of the battery pack involved in Comparative Example 2.

[0011] Figure 6 It means Figure 5 A cross-sectional view of the shape of section VI.

[0012] Figure 7 This is a diagram showing a simplified shape of the casing of a battery pack according to one embodiment.

[0013] Figure 8 It means Figure 7 A cross-sectional view of the shape of section VIII.

[0014] Figure 9 This is a diagram showing the state of the battery pack before the casing is assembled according to Embodiment 1.

[0015] Figure 10 This is a diagram showing the state of the battery pack after the casing is assembled according to Embodiment 1.

[0016] Figure 11 This is a diagram showing the state of the battery pack before the casing is assembled according to Embodiment 2.

[0017] Figure 12 This is a diagram showing the state of the battery pack after the casing is assembled according to Embodiment 2.

[0018] Figure 13 This is a diagram showing the state of the battery pack before the casing is assembled according to Embodiment 3.

[0019] Figure 14 This is a diagram showing the state of the battery pack after the casing is assembled according to Embodiment 3.

[0020] Figure 15 This is a diagram showing the state of the battery pack before the casing is assembled according to Embodiment 4.

[0021] Figure 16 This is a diagram showing the state of the battery pack after the casing is assembled according to Embodiment 4.

[0022] Figure 17 This is a diagram showing the state of the battery pack before the casing is assembled according to Embodiment 5.

[0023] Figure 18 This is a diagram showing the state of the battery pack after the casing is assembled according to Embodiment 5.

[0024] Figure 19 This is a diagram showing the state of the battery pack before the casing is assembled according to Embodiment 6.

[0025] Figure 20 This is a diagram showing the state of the battery pack after the casing is assembled according to Embodiment 6.

[0026] Figure 21 This is a diagram showing the state of the battery pack before the casing is assembled according to Embodiment 7.

[0027] Figure 22 This is a diagram showing the state of the battery pack after the casing is assembled according to Embodiment 7. Detailed Implementation

[0028] The following describes the implementation of this technology. Furthermore, there are instances where the same or equivalent parts are labeled with the same reference numerals without repeating their description.

[0029] Furthermore, in the embodiments described below, when numbers, quantities, etc., are mentioned, the scope of this technology is not necessarily limited to those numbers, quantities, etc., unless specifically stated otherwise. Additionally, in the embodiments described below, each structural element is not necessarily essential to this technology, unless specifically stated otherwise. Furthermore, this technology is not necessarily limited to achieving all the effects mentioned in these embodiments.

[0030] Furthermore, in this specification, the terms "comprise," "include," and "have" are open-ended. That is, when a structure is included, other structures besides that structure may be included, or they may not be included.

[0031] Furthermore, when using geometric terms and terms indicating positional or directional relationships, such as "parallel," "orthogonal," "tilted at 45°," "coaxial," or "along," these terms allow for some degree of error or variation. When using terms indicating relative positional relationships, such as "upper side" or "lower side," these terms are used to indicate relative positional relationships in a given state. Depending on the orientation of each mechanism (e.g., reversing the overall orientation of the mechanism), the relative positional relationships can be reversed or rotated to any angle.

[0032] In this specification, "battery" is not limited to lithium-ion batteries and may include other batteries such as nickel-metal hydride batteries. In this specification, "electrode" can be collectively referred to as positive electrode and negative electrode. Additionally, "electrode plate" can be collectively referred to as positive electrode plate and negative electrode plate.

[0033] Figure 1 This is an exploded perspective view showing the structure of battery pack 1. Battery pack 1 includes multiple battery cells 100, a housing 200, a heat-conducting component 300, and a cooling plate 400.

[0034] Multiple battery cells 100 are stacked along the Y-axis (first direction). A housing 200 houses the multiple battery cells 100. The housing 200 can be, for example, a cast part (die-cast) made of a metal material such as aluminum or magnesium, or a stamped part made of a carbon-containing material. The housing 200 is not limited to the above-described form; it can be used as long as it meets the specified characteristics in terms of strength, heat dissipation, and thermal conductivity. For example, the housing 200 can also be made of resin.

[0035] The heat conduction element 300 is disposed between the battery cell 100 and the housing 200 to facilitate the transfer of heat generated in the battery cell 100 to the housing 200.

[0036] The cooling plate 400 (heat dissipation promotion mechanism) promotes heat dissipation from the housing 200. As an example, the cooling plate 400 is a water-cooled cooling unit including a flow path for coolant flow; however, the heat dissipation promotion mechanism is not limited to a water-cooled cooling device. For example, forced air cooling or natural heat dissipation methods (heat sinks, etc.) can also be used. Furthermore, the housing 200 and the cooling plate 400 can be integrated, or the cooling plate 400 can be provided inside the housing 200. Heat dissipation from the battery cell 100 is not limited to indirect heat dissipation via the housing 200; direct heat dissipation from the battery cell 100 is also possible.

[0037] Figure 2 This is a diagram representing battery cell 100. (Example) Figure 2 As shown, the battery cell 100 includes electrode terminals 110 and a housing 120. The electrode terminals 110 include a positive terminal 111 and a negative terminal 112. The electrode terminals 110 are formed on the housing 120. Electrode bodies (not shown) and electrolyte are housed in the housing 120.

[0038] The shell 120 is formed into a cubic shape with flat surfaces. The shell 120 has an extending top surface 121 and a bottom surface 122 along the X-Y plane. The top surface 121 and the bottom surface 122 are opposite each other along the Z-axis direction (second direction).

[0039] As an example, battery cell 100 is a lithium-ion battery. Battery cell 100 can also be other batteries such as nickel-metal hydride batteries. In addition, the battery cell involved in this technology is not limited to a square battery cell; for example, it can also be a cylindrical battery cell.

[0040] Figure 3 This is a diagram showing the simplified shape of the casing 200A involved in Comparative Example 1. Figure 4 It means Figure 3 A cross-sectional view of the shape of section IV.

[0041] like Figure 3As shown, the housing 200A includes a first component 210A and a second component 220A that together with the first component 210A forms an internal space 230A.

[0042] like Figure 4 As shown, a sealing portion 240A is provided to seal the joint between the first component 210A and the second component 220A. The first component 210A has a first portion 211A that abuts against the sealing portion 240A, and the second component 220A has a second portion 221A that faces the first portion 211A across the sealing portion 240A.

[0043] The sealing part 240A is configured along an X-Y plane orthogonal to the Z-axis direction. When the pressure inside the internal space 230A of the housing 200A increases, the peeling direction ( Figure 4 The force (in the direction of arrow A) acts on the sealing part 240A, which is clamped by the first part 211A of the first component 210A and the second part 221A of the second component 220A.

[0044] Figure 5 This is a diagram showing a simplified shape of the casing of the battery pack involved in Comparative Example 2. Figure 6 It means Figure 5 A cross-sectional view of the shape of section VI.

[0045] exist Figure 5 , Figure 6 In Comparative Example 2 shown, the sealing portion 240A is also configured along an X-Y plane orthogonal to the Z-axis direction. When the pressure in the internal space 230A increases, the peeling direction ( Figure 6 The force (in the direction of arrow A) acts on the sealing part 240A, which is clamped by the first part 211A of the first component 210A and the second part 221A of the second component 220A.

[0046] Figure 7 This is a diagram showing a simplified shape of the casing 200 of the battery pack according to this embodiment. Figure 8 It means Figure 5 A cross-sectional view of the shape of section VIII.

[0047] like Figure 7 As shown, the housing 200 has an internal space 230 for accommodating multiple battery cells 100. The housing 200 includes a first component 210 and a second component 220 that together with the first component 210 forms the internal space 230. The first component 210 constitutes the cover of the housing 200, and the second component 220 constitutes the bottom of the housing 200.

[0048] like Figure 8As shown, a sealing portion 240 is provided to seal the joint between the first component 210 and the second component 220. The first component 210 has a first portion 211 that abuts against the sealing portion 240, and the second component 220 has a second portion 221 that is opposite to the first portion 211 across the sealing portion 240.

[0049] A sealing portion 240 is provided along the side wall portion of the housing 200. The side wall portion of the housing 200 is a portion that extends in the Z-axis direction substantially parallel to the side surface of the battery unit 100. The sealing portion 240 is provided along the Z-axis direction. The sealing portion 240 is provided around the entire circumference of the housing 200 in the X-Y plane. In this way, the internal space 230 of the housing 200 is sealed.

[0050] For example, if thermal runaway occurs in one of the multiple battery cells 100 and gas is ejected from the casing 120, the pressure in the internal space 230 of the casing 200 increases. The increased pressure in the internal space 230 acts as an expansion pressure on the casing 200. At this time, the shear direction ( Figure 8 The force (in the direction of arrow A) acts on the sealing part 240, which is held by the first part 211 of the first component 210 and the second part 221 of the second component 220.

[0051] In the battery pack according to this embodiment, when expansion pressure acts on the casing 200, the sealing portion 240 is subjected to a shear force rather than a peeling force. This results in greater durability compared to the case where a peeling force is applied to the sealing portion 240. In the battery packs of Comparative Examples 1 and 2, subsequent disassembly (removal of the first component 210A from the second component 220A) is predetermined after the casing 200A is assembled. In contrast, the casing 200 according to this embodiment is obtained based on a transformation of the concept that does not necessarily presuppose the disassembly of the casing 200.

[0052] Figure 9 , Figure 10 This is a diagram showing the housing 200 involved in Embodiment 1. Figure 9 This indicates the state before the outer casing is assembled (200). Figure 10 This indicates the state after the outer casing 200 is assembled.

[0053] exist Figure 9 , Figure 10 In the illustrated embodiment 1, the first portion 211 of the first component 210 is located outside the housing 200 relative to the second portion 221 of the second component 220. The first portion 211 and the second portion 221 extend parallel to each other. Both the first portion 211 and the second portion 221 are formed to extend in the Z-axis direction.

[0054] Figure 11 , Figure 12This is a diagram showing the housing 200 involved in Embodiment 2. Figure 11 This indicates the state before the outer casing is assembled (200). Figure 12 This indicates the state after the outer casing 200 is assembled.

[0055] exist Figure 11 , Figure 12 In Embodiment 2, similar to Embodiment 1, the first portion 211 of the first component 210 is also located outside the housing 200 relative to the second portion 221 of the second component 220. The first portion 211 is formed to extend in the Z-axis direction. The second portion 221 is inclined relative to the Z-axis direction in a manner that it faces inward toward the front end side and toward the inside of the housing 200. Therefore, the first portion 211 and the second portion 221 move away from each other (the distance between them increases) from the root side (bottom side of the housing 200) of the second portion 221 toward the front end side (cover side of the housing 200) of the second portion 221. By inclining the second portion 221 as described above, it is easier to combine the first component 210 and the second component 220. In addition, the sealing portion 240 can be supported from the bottom side of the housing 200 by the second portion 221, thus preventing the sealing material from falling off when the first component 210 and the second component 220 are combined.

[0056] Figure 13 , Figure 14 This is a diagram showing the housing 200 involved in Embodiment 3. Figure 13 This indicates the state before the outer casing is assembled (200). Figure 14 This indicates the state after the outer casing 200 is assembled.

[0057] exist Figure 13 , Figure 14 In Embodiment 3, similar to Embodiments 1 and 2, the first portion 211 of the first component 210 is also located outside the housing 200 relative to the second portion 221 of the second component 220. The first portion 211 is inclined relative to the Z-axis direction, moving outward from the housing 200 towards the front end side. The second portion 221 is formed to extend in the Z-axis direction. Therefore, the first portion 211 and the second portion 221 move away from each other (the spacing increases) from the root side (cover side of the housing 200) of the first portion 211 towards the front end side (bottom side of the housing 200). By inclining the first portion 211 as described above, the combination of the first component 210 and the second component 220 is facilitated. Furthermore, compared to the construction of Embodiment 2, the components of Embodiment 3 are easier to manufacture.

[0058] Figure 15 , Figure 16 This is a diagram showing the housing 200 involved in Embodiment 4. Figure 15 This indicates the state before the outer casing is assembled (200). Figure 16This indicates the state after the outer casing 200 is assembled.

[0059] exist Figure 15 , Figure 16 In Embodiment 4, the first portion 211 of the first component 210 is located inside the housing 200 relative to the second portion 221 of the second component 220. The first portion 211 is formed to extend in the Z-axis direction. The second portion 221 is inclined relative to the Z-axis direction in such a way that it faces outward from the housing 200 as it moves toward the front end side. Therefore, the first portion 211 and the second portion 221 move away from each other (the distance between them increases) from the root side (bottom side of the housing 200) of the second portion 221 toward the front end side (cover side of the housing 200) of the second portion 221. By inclining the second portion 221 as described above, it is easier to combine the first component 210 and the second component 220. In addition, the sealing portion 240 can be supported from the bottom side of the housing 200 by the second portion 221, thus preventing the sealing material from falling off when the first component 210 and the second component 220 are combined. Furthermore, the structure of Embodiment 4 is the same as that of Embodiment 3, and the components are easier to manufacture compared to the structure of Embodiment 2. Furthermore, since the first part 211 and the second part 221 are formed with the end of the sealing part 240 exposed to the cover side of the housing 200, the sealing part 240 can be confirmed from the upper side (cover side) of the housing 200 when the first part 210 and the second part 220 are combined, and the alignment is easy.

[0060] Figure 17 , Figure 18 This is a diagram showing the housing 200 involved in Embodiment 5. Figure 17 This indicates the state before the outer casing is assembled (200). Figure 18 This indicates the state after the outer casing 200 is assembled.

[0061] exist Figure 17 , Figure 18In Embodiment 5, as in Embodiment 4, the first portion 211 of the first component 210 is also located inside the housing 200 relative to the second portion 221 of the second component 220. The second portion 221 of the second component 220 is formed such that its front end is located away from the bottom of the housing 200. The second portion 221 is inclined relative to the Z-axis direction in such a way that it faces outward from the housing 200 as it faces the front end. The first portion 211 is formed to extend in the Z-axis direction. Therefore, the first portion 211 and the second portion 221 move away from each other (the spacing increases) from the root side (cover side of the housing 200) of the first portion 211 toward the front end side (bottom side of the housing 200). By inclining the second portion 221 as described above, it is easier to combine the first component 210 and the second component 220. Furthermore, since the first part 211 and the second part 221 are formed such that the end of the sealing part 240 is exposed to the cover side of the housing 200, the sealing part 240 can be seen from the upper side (cover side) of the housing 200 when the first part 210 and the second part 220 are combined, and the alignment is easy.

[0062] Figure 19 , Figure 20 This is a diagram showing the housing 200 involved in Embodiment 6. Figure 19 This indicates the state before the outer casing is assembled (200). Figure 20 This indicates the state after the outer casing 200 is assembled.

[0063] exist Figure 19 , Figure 20 In Embodiment 6, as in Embodiment 5, the second portion 221 of the second component 220 is also formed such that its front end is located away from the bottom of the housing 200. Both the first portion 211 and the second portion 221 are inclined relative to the Z-axis direction, such that they are inclined towards the outside of the housing 200 as they are towards the front end side. The first portion 211 and the second portion 221 approach each other (the gap decreases) from the root side (the cover side of the housing 200) of the first portion 211 and the second portion 221 towards the front end side (the bottom side of the housing 200). By inclining the second portion 221 as described above, the sealing portion 240 can be supported from the bottom side of the housing 200 by the second portion 221, thus preventing the sealing material from falling off when the first component 210 and the second component 220 are combined.

[0064] Figure 21 , Figure 22 This is a diagram showing the housing 200 involved in Embodiment 7. Figure 21 This indicates the state before the outer casing is assembled (200). Figure 22 This indicates the state after the outer casing 200 is assembled.

[0065] exist Figure 21 , Figure 22In the illustrated embodiment 7, the first portion 211 of the first component 210 is located inside the housing 200 relative to the second portion 221 of the second component 220. A protrusion 222 is formed on the sidewall of the second component 220, protruding toward the internal space 230. When the first component 210 and the second component 220 are assembled, the front end of the first portion 211 abuts against the protrusion 222.

[0066] To ensure a tight seal, the thickness of the sealing portion 240 after combining the first component 210 and the second component 220 should be as small as possible, for example, preferably less than 10 mm.

[0067] The length of the sealing portion 240 in the Z-axis direction after combining the first component 210 and the second component 220 is appropriately determined according to the characteristics of the sealing material and the size of the housing 200, but it is preferably about 100 mm or less.

[0068] The sealing part 240 can be formed of, for example, the following materials.

[0069] (1) Gel-like materials

[0070] (a) Sikaflex221 (polyurethane-based) moisture-curing type [manufactured by Sika]

[0071] Chemical resistance: Resistant to fresh water, seawater, lime water, sewage, dilute acids, and dilute alkali solutions.

[0072] Hardness (CQP023-1 / ISO868): Shore A40

[0073] Tensile strength (CQP036-1 / ISO37): 1.8 MPa

[0074] Elongation at break (CQP036-1 / ISO37): 500%

[0075] Tear strength (CQP045-1 / ISO34): 7 N / mm

[0076] Long-term heat resistance temperature (CQP513-1): +90℃

[0077] Short-term heat resistance temperature: approximately +120℃ for up to 1 day, approximately +140℃ for up to 1 hour.

[0078] Application temperature range: -40℃~+90℃

[0079] (b) BESIL9339 (silicone-based) room temperature curing type [manufactured by BEGINOR]

[0080] Hardness (GB / T531-2008): Shore A40

[0081] Tensile strength (CQP036-1 / ISO37): 2.8 MPa

[0082] Elongation at break (GB / T528-2009): 500%

[0083] Shear strength (GB / T7124-2008): 2.3 MPa

[0084] Application temperature range: -60℃ to +250℃

[0085] (c)DOWSILEA-4700 (Silicone-based) Room Temperature Curing Type [Toray Industries]

[0086] Hardness: JIS type A19

[0087] Tensile strength (CQP036-1 / ISO37): 3.7 MPa

[0088] Elongation at break (GB / T528-2009): 630%

[0089] Application temperature range: -45~150℃

[0090] (d) SU-3802 (Carbamate-based) Room temperature curing type [Made with Sanyou Resin]

[0091] Chemical resistance: LLC, engine oil

[0092] Hardness: ASTM D2240, Type A43

[0093] Elastic modulus (DMS method): 2.4 MPa

[0094] Tensile strength (JISK6301): 1.5 MPa

[0095] Elongation at break (JISK6301): 100%

[0096] (e) MS650 (Modified Silane) Moisture-Curing Type [Henkel]

[0097] Hardness (ISO 868, Durometer A): Shore A 60

[0098] Tensile strength (ISO 37): 3.0 MPa

[0099] Elongation at break (ISO 37): 180%

[0100] Shear strength (DIN EN 1465): 2.0 MPa

[0101] Application temperature range: -40℃~+90℃

[0102] (f) EAE-60HP (Epoxy) Room Temperature Curing Type [Henkel]

[0103] Chemical resistance: organic solvents

[0104] Hardness (ISO 868, Durometer D): 80

[0105] Tensile strength (ISO 527-2): 35 MPa

[0106] Elongation at break (ISO 527-3): 9%

[0107] (2) Reworkable materials (a) TB3081J (acrylic) UV-curable [tribond]

[0108] Heat resistance, cold resistance

[0109] Hardness (3TS-215-01, Hardness Tester A): A27

[0110] Elastic modulus (3TS-501-04): 2.1 MPa

[0111] Tensile strength (3TS-320-01): 1.8 MPa

[0112] Elongation at break (3TS-320-01): 180%

[0113] Application temperature range: -40℃~+120℃

[0114] (b) Loctite AA5884 (Acrylic) UV Curing Type [Henkel] Chemical Resistance: Oil Resistance

[0115] Hardness (ISO 868, Durometer A): A55-65

[0116] Tensile strength (ISO 37): 4.0 MPa

[0117] Elongation at break (ISO 37): 200%

[0118] Application temperature range: -40℃ to +150℃

[0119] (c) ACG-576 (Acrylic) UV Curing Type [Sekisui Chemicals]

[0120] Chemical resistance: Oil resistance

[0121] Hardness (Durometer A): 30

[0122] Tensile strength (ISO 37): 2.1 MPa

[0123] Elongation at break (ISO 37): 285%

[0124] According to the battery pack 1 of this embodiment, the size of the sealing portion 240 can be reduced to reduce the cost of the materials used to form the sealing portion 240, and the fastening members of the first component 210 and the second component 220 used to obtain the durability of the casing 200 can be omitted. Therefore, the manufacturing cost of the battery pack 1 can be reduced without compromising the sealing performance of the casing 200.

[0125] Embodiments of the present invention have been described, but all points of the embodiments disclosed herein should be considered illustrative and not intended to limit the invention. The scope of the invention is defined by the claims and is intended to include all equivalents thereof and all modifications within the scope thereof.

Claims

1. A battery pack, wherein, The battery pack includes: Multiple battery cells are arranged along the first direction; and The casing has an internal space for accommodating the multiple battery cells. The housing includes a first component, a second component that forms the internal space together with the first component, and a sealing portion that seals the joint between the first component and the second component. The first component has a first portion that abuts against the sealing portion. The second component has a second portion that is opposite to the first portion across the sealing portion. The first part is located inside the outer casing relative to the second part. A protrusion is formed on the side wall of the second component, protruding toward the internal space. The first component and the second component are combined such that the front end of the first part abuts against the protrusion. When the expansion pressure of the internal space acts on the outer shell, the shear force acts on the sealing portion clamped by the first part and the second part.

2. The battery pack according to claim 1, wherein, The plurality of battery cells each have a top surface on which electrode terminals are provided, and a bottom surface opposite the top surface along a second direction orthogonal to the first direction. The housing includes a bottom located on the bottom side of the plurality of battery cells, a cover portion opposite to the bottom along the second direction, and a sidewall portion located between the bottom and the cover portion. The sealing portion is formed along the sidewall portion.

3. The battery pack according to claim 2, wherein, The second component is located on the bottom side of the housing relative to the first component. The second part of the second component is formed to be inclined in a direction relative to the second direction, such that it supports the sealing portion from the bottom side.

4. The battery pack according to claim 2 or 3, wherein, The first part and the second part are formed such that the end of the sealing part is exposed toward the cover side of the housing.

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