Battery pack

Abstract

A battery pack (1) is provided with a plurality of battery cells (100) and a case (200) having a first space (200A) for housing the plurality of battery cells (100), the case (200) comprising a main body (210) having a bottom surface and a bottom surface cover (230) facing the bottom surface of the main body (210) from the outside side, and the main body (210) and the bottom surface cover (230) are fastened to each other at a plurality of fastening parts (240) including a first fastening part and a second fastening part. The main body (210) has a recessed portion facing the bottom cover (230), a second space (210B) is formed between the recessed portion and the bottom cover (230), the second space (210B) communicates with the first space (200A), the housing (200) has an opening (200B) that communicates the second space (210B) with the outside of the housing (200), and the opening (200B) is located between the first fastening portion and the second fastening portion.

Description

Technical Field

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

[0002] A battery pack having a gas discharge path provided in a casing is known in the art. Examples of the prior art include Japanese Unexamined Patent Application Publication No. 2022-510652, Japanese Unexamined Patent Application Publication No. 2023-124435, and Japanese Unexamined Patent Application Publication No. 2023-124436. Summary of the invention

[0003] From the viewpoint of suppressing structural complexity and suppressing deformation of the case during gas discharge, there is still room for improvement in conventional battery packs.

[0004] The present technology aims to provide a battery pack that can suppress deformation of a casing during gas discharge with a simple structure.

[0005] This technology provides the following battery packs.

[0006] [1] A battery pack, wherein the battery pack comprises: a plurality of battery cells; and a shell having a first space for accommodating the plurality of battery cells, the shell comprising a main body having a bottom surface and a bottom cover facing the bottom surface of the main body from the outside, the main body and the bottom cover being fastened to each other at a plurality of fastening portions including a first fastening portion and a second fastening portion, the main body having a recess facing the bottom cover, a second space being formed between the recess and the bottom cover, the second space being connected to the first space, and the shell having an opening for connecting the second space to the outside of the shell, the opening being located between the first fastening portion and the second fastening portion.

[0007] [2] The battery pack according to [1], wherein the main body is formed of a cast component.

[0008] [3] The battery pack described in [1] or [2], wherein the bottom cover is formed of a plate-like member.

[0009] [4] The battery pack described in [1] or [2], wherein the bottom cover has another recessed portion facing the recessed portion of the body.

[0010] [5] The battery pack according to any one of [1] to [4], wherein the battery pack further comprises a gas-permeable membrane member, the membrane member being arranged so as to block a connection between the first space and the second space.

[0011] [6] The battery pack according to [5], wherein the membrane member opens the communication portion when the pressure in the first space exceeds a predetermined pressure.

[0012] [7] The battery pack according to any one of claims [1] to [6], wherein a third space for a coolant passage is formed between the bottom surface of the main body and the bottom cover.

[0013] The foregoing and other objects, features, configurations and advantages of the present invention will become more apparent from the following detailed description of the present invention when taken in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a three-dimensional diagram of the battery pack.

[0015] Figure 2 It is a three-dimensional diagram of the battery pack contained in the battery pack.

[0016] Figure 3 This is a perspective view of a battery cell included in a battery pack.

[0017] Figure 4 It is a bottom view of the shell body of the battery pack.

[0018] Figure 5 yes Figure 4 V-V section view in.

[0019] Figure 6 It is a perspective view showing the vicinity of the opening of the duct.

[0020] Figure 7 yes Figure 6 Section view VII-VII in the figure.

[0021] Figure 8 This is a diagram showing the bottom surface of the casing body, illustrating the periphery of the duct. DETAILED DESCRIPTION

[0022] Hereinafter, embodiments of the present technology will be described. In addition, the same reference numerals are given to the same or corresponding parts, and their description may not be repeated.

[0023] In addition, in the embodiments described below, when the number, amount, etc. are mentioned, unless otherwise specified, the scope of the present technology is not necessarily limited to the number, amount, etc. In addition, in the following embodiments, each component is not an essential component for the present technology unless otherwise specified. In addition, the present technology is not limited to a configuration that necessarily exerts all the effects mentioned in the embodiments.

[0024] In addition, in this specification, the descriptions such as “comprise”, “include”, and “have” are not limiting. That is, when a certain structure is included, other structures other than the structure may be included or not.

[0025] In addition, in this specification, when geometrical terms and terms indicating position and direction relationships such as "parallel", "orthogonal", "oblique 45°", "coaxial", "along" and the like are used, these terms allow for manufacturing errors or slight variations. In this specification, when terms such as "upper side" and "lower side" are used to indicate relative positional relationships, these terms are used as terms indicating relative positional relationships in one state, and the relative positional relationships can be reversed or rotated to any angle depending on the installation direction of each mechanism (for example, turning the entire mechanism upside down, etc.).

[0026] In this specification, "battery" is not limited to lithium-ion batteries, but may also include other batteries such as nickel-hydrogen batteries and sodium-ion batteries. In this specification, positive electrodes and negative electrodes may be collectively referred to as "electrodes".

[0027] In this specification, "battery unit" is not limited to square structure, and may also include cylindrical, soft-pack, blade-shaped and other shaped units. "Battery unit" can be installed in hybrid electric vehicles (HEV: Hybrid Electric Vehicle), plug-in hybrid electric vehicles (PHEV: Plug-in Hybrid Electric Vehicle) and pure electric vehicles (BEV: Battery Electric Vehicle). However, the use of "battery unit" is not limited to vehicle use.

[0028] Figure 1 FIG. 1 is a perspective view of a battery pack according to the present embodiment. Figure 1 As shown, the battery pack 1 includes a case 200 . The battery pack 10 is accommodated in an internal space 200A (first space) of the case 200 .

[0029] exist Figure 1 In the example, the battery pack 10 includes three battery packs 11, 12, and 13. The battery pack 11 (first stack), the battery pack 12 (second stack), and the battery pack 13 (third stack) include a plurality of battery cells arranged in the Y-axis direction (first direction), and are arranged in parallel with each other in the X-axis direction (second direction).

[0030] The housing 200 includes a main body 210, an upper cover 220, and a bottom cover 230. The main body 210, the upper cover 220, and the bottom cover 230 are fastened to each other at a plurality of fastening portions 240 each consisting of bolts or the like.

[0031] The internal space 200A of the housing 200 is formed by the main body 210 and the upper cover 220. A refrigerant passage 210A and an exhaust duct 210B (see FIG. 2 ) described below are formed between the bottom surface of the main body 210 and the bottom cover 230. Figure 4 , Figure 5 ).

[0032] like Figure 1 As shown, the housing 200 is provided with an opening 200B for communicating the exhaust duct 210B with the outside of the housing 200, an inlet 200C for allowing the refrigerant to pass through the refrigerant passage 210A, and an outlet 200D for allowing the refrigerant to exit from the refrigerant passage 210A.

[0033] Figure 2 It is a perspective view of the battery pack 10 . Figure 2 The battery pack 10 shown includes battery cells 100 and insulating members 100A (cell spacers). The battery cells 100 and the insulating members 100A are alternately arranged along the Y-axis direction (first direction).

[0034] The battery cells 100 are rectangular battery cells, and a plurality of battery cells 100 are provided along the Y-axis direction. The plurality of battery cells 100 are electrically connected to each other via bus bars (not shown).

[0035] The insulating member 100A is provided between the plurality of battery cells 100. The insulating member 100A prevents unintended conduction of the adjacent battery cells 100. The insulating member 100A ensures electrical insulation of the adjacent battery cells 100.

[0036] By housing the battery pack 10 in the housing 20, a Figure 1 The battery pack 1 may be a structure in which the wall surface 22 of the housing 20 directly supports the stack of battery cells 100 and insulating members 100A (Cell-to-Pack structure, i.e., module-free structure), or a structure in which a battery module including a plurality of battery cells 100 and insulating members 100A is accommodated in the housing 20 (Cell-Module-Pack structure, i.e., conventional module structure).

[0037] Figure 3 is a perspective view showing the battery unit 100. Figure 3 As shown, the battery cell 100 has a square shape. The battery cell 100 has an electrode terminal 110 , a battery case 120 , and a gas discharge valve 130 .

[0038] The electrode terminal 110 is formed on the battery case 120. The electrode terminal 110 includes a positive terminal 111 and a negative terminal 112 arranged along the X-axis direction (second direction) orthogonal to the Y-axis direction (first direction). The positive terminal 111 and the negative terminal 112 are provided to be separated from each other in the X-axis direction.

[0039] The battery case 120 has a rectangular parallelepiped shape and forms the appearance of the battery cell 100. The battery case 120 includes a case body 120A that accommodates an electrode body and an electrolyte (not shown) and a sealing plate 120B that seals the opening of the case body 120A. The sealing plate 120B is joined to the case body 120A by welding.

[0040] The battery case 120 has an upper surface 121 , a lower surface 122 , a first side surface 123 , a second side surface 124 , and two third side surfaces 125 .

[0041] The upper surface 121 is a plane perpendicular to the Z-axis direction (third direction) (perpendicular to the Y-axis direction and the X-axis direction). The electrode terminal 110 is arranged on the upper surface 121. The lower surface 122 faces the upper surface 121 along the Z-axis direction.

[0042] Each of the first side surface 123 and the second side surface 124 is composed of a plane orthogonal to the Y-axis direction. Each of the first side surface 123 and the second side surface 124 has the largest area among the multiple side surfaces of the battery case 120. Each of the first side surface 123 and the second side surface 124 has a rectangular shape when viewed in the Y-axis direction. Each of the first side surface 123 and the second side surface 124 has a rectangular shape with the X-axis direction as the long side direction and the Z-axis direction as the short side direction when viewed in the Y-axis direction.

[0043] The plurality of battery cells 100 are stacked such that the first side surfaces 123 and the second side surfaces 124 face each other between the battery cells 100 and 100 adjacent to each other in the Y-axis direction. Thus, the positive terminals 111 and the negative terminals 112 are alternately arranged in the Y-axis direction of the stacked plurality of battery cells 100.

[0044] The gas discharge valve 130 is provided on the upper surface 121 . When the temperature of the battery cell 100 rises (thermal runaway) and the internal pressure of the battery case 120 becomes higher than a predetermined value due to the gas generated inside the battery case 120 , the gas discharge valve 130 discharges the gas to the outside of the battery case 120 .

[0045] Figure 4 is a bottom view of the main body 210 of the housing 200, Figure 5 yes Figure 4 V-V section view in.

[0046] like Figure 4, Figure 5 As shown, a recessed portion facing the bottom cover 230 is formed in the main body 210 , and the recessed portion constitutes the refrigerant passage 210A and the exhaust duct 210B.

[0047] The main body 210 is a casting component made of a metal such as aluminum. The upper cover 220 and the bottom cover 230 are plate-shaped members made of a metal such as aluminum. However, the bottom cover 230 may be made of a casting component, and another concave portion facing the concave portion of the main body 210 may be provided, and the two concave portions facing each other may be combined to form the refrigerant passage 210A and the exhaust duct 210B.

[0048] The coolant passage 210A (third space) is formed between the bottom surface of the main body 210 and the bottom cover 230. The coolant passage 210A is formed to extend in the Y-axis direction directly below each of the battery packs 11, 12, and 13. Figure 4 In the example of FIG. 1 , the first portion 211A is formed directly below the battery pack 11, the second portion 212A is formed directly below the battery pack 12, and the third portion 213A is formed directly below the battery pack 13. The refrigerant flowing into the refrigerant passage 210A from the inlet portion 200C flows through the first portion 211A, then flows through the second portion 212A, and then flows through the third portion 213A, and then flows out from the outlet portion 200D to the outside of the housing 200. By making the refrigerant (e.g., water) flow directly below the battery packs 11, 12, and 13, the cooling of the battery unit 100 is promoted.

[0049] An exhaust duct 210B (second space) serving as an exhaust passage is formed between the bottom surface of the main body 210 and the bottom cover 230. The exhaust duct 210B is connected to the internal space 200A of the housing 200, and is also connected to the outside of the housing 200 through the opening 200B. A breathable breathing membrane 250 (membrane member) is provided in a manner that blocks the connecting portion between the internal space 200A of the housing 200 and the exhaust duct 210B. When the pressure of the internal space 200A does not exceed a predetermined pressure, the breathing membrane 250 allows air components to pass through while suppressing the intrusion of moisture into the internal space 200A. When the pressure of the internal space 200A exceeds a predetermined pressure (when the pressure rises abnormally), the breathing membrane 250 ruptures, and the connecting portion between the internal space 200A and the exhaust duct 210B is opened, thereby promoting the discharge of gas and the like from the internal space 200A.

[0050] The main body 210 and the bottom cover 230 are fastened to each other at the fastening portion 260 provided between the first portion 211A and the second portion 212A and between the second portion 212A and the third portion 213A. In other words, the refrigerant passage 210A is provided on both sides of the fastening portion 260 in the X-axis direction so as to extend in the Y-axis direction.

[0051] Figure 6 2 is a perspective view showing the vicinity of the opening 200B of the exhaust duct 210B. Figure 7 yes Figure 6 Section view VII-VII in the figure. Figure 8 It is a diagram showing the bottom surface of the main body 210 and illustrating the periphery of the exhaust duct 210B.

[0052] like Figures 6 to 8 As shown, the opening 200B of the exhaust duct 210B is located between the two fastening parts 240 (the first fastening part and the second fastening part). When the pressure of the internal space 200A of the housing 200 rises and the gas is discharged through the exhaust duct 210B, the housing 200 (bottom cover 230) is deformed around the opening 200B, and it is necessary to suppress the discharge from unexpected parts. On the other hand, from the perspective of reducing manufacturing costs and saving space when mounted on a vehicle, it is also necessary to suppress the complexity of the structure of the housing 200.

[0053] In the battery pack 1 according to the present embodiment, as described above, by providing the opening 200B of the exhaust duct 210B between the two fastening portions 240 , an increase in the number of components can be suppressed, while deformation of the case 200 and discharge from an unexpected position can be suppressed.

[0054] The embodiments of the present invention have been described above, but the embodiments disclosed this time should be considered to be illustrative in all aspects and not restrictive. The scope of the present invention is indicated by the claims, and is intended to include all modifications within the meaning and scope equivalent to the claims.

Claims

1. A battery pack, wherein: The battery pack has: a plurality of battery cells; and a housing having a first space for accommodating the plurality of battery cells; The housing includes a main body having a bottom surface and a bottom surface cover facing the bottom surface of the main body from the outside. The main body and the bottom cover are fastened to each other at a plurality of fastening parts including a first fastening part and a second fastening part. The main body has a recessed portion facing the bottom cover, a second space is formed between the recessed portion and the bottom cover, and the second space is communicated with the first space. The housing has an opening that allows the second space to communicate with the outside of the housing, and the opening is located between the first fastening portion and the second fastening portion.

2. The battery pack according to claim 1, wherein: The main body is composed of a cast component.

3. The battery pack according to claim 1 or 2, wherein: The bottom cover is composed of a plate-shaped member.

4. The battery pack according to claim 1 or 2, wherein: The bottom cover has another recessed portion facing the recessed portion of the main body.

5. The battery pack according to claim 1 or 2, wherein: The battery pack further includes a gas-permeable film member provided so as to block a communication portion between the first space and the second space.

6. The battery pack according to claim 5, wherein: The membrane member opens the communication portion when the pressure of the first space exceeds a predetermined pressure.

7. The battery pack according to claim 1 or 2, wherein: A third space for a refrigerant passage is formed between the bottom surface of the main body and the bottom surface cover.

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