Battery pack

Abstract

To provide a battery pack which can suppress deformation of a case at the time of gas discharge by a simple configuration.SOLUTION: The battery pack includes: a plurality of battery cells; and a case having a first space for storing the battery cells. The case includes a body with an opening and a bottom cover facing the bottom surface of the body from the outside. The body and the bottom cover are fastened to each other in a plurality of fastening parts including a first fastening part and a second fastening part.The body part has a recessed part facing the bottom cover. A second space is formed between the recessed part and the bottom cover. The second space leads to the first space. The case has an opening for allowing the second space and the outside of the case to lead to each other. The opening is located between the first fastening part and the second fastening part.SELECTED DRAWING: Figure 6

Description

[Technical field]

[0001] The present technology relates to battery packs. [Background technology]

[0002] Battery packs having a gas exhaust path in the case have been known for some time. Prior art includes JP-T-2022-510652 (Patent Document 1), JP-A-2023-124435 (Patent Document 2), and JP-A-2023-124436 (Patent Document 3). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Special Publication No. 2022-510652 [Patent Document 2] JP 2023-124435 A [Patent Document 3] JP 2023-124436 A Summary of the Invention [Problem to be solved by the invention]

[0004] From the viewpoint of suppressing deformation of the case when gas is discharged while suppressing an increase in structural complexity, there is still room for improvement in conventional battery packs.

[0005] An object of the present technology is to provide a battery pack that is capable of suppressing deformation of the case when gas is discharged using a simple structure. [Means for solving the problem]

[0006] The present technology provides the following battery pack.

[0007] [1] A battery pack comprising: a plurality of battery cells; and a case having a first space for housing the plurality of battery cells, the case including 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 parts including a first fastening part and a second fastening part, 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 in communication with the first space, the case having an opening connecting the second space to the outside of the case, the opening being located between the first fastening part and the second fastening part.

[0008] [2] The battery pack according to [1], wherein the main body is made of a cast part.

[0009] [3] The battery pack according to [1] or [2], wherein the bottom cover is made of a plate-shaped member.

[0010] [4] The battery pack described in [1] or [2], wherein the bottom cover has another recess facing the recess of the main body.

[0011] [5] The battery pack described in any one of [1] to [4], further comprising a breathable membrane member arranged to block the communication portion between the first space and the second space.

[0012] [6] The battery pack described in [5], wherein the membrane member opens the communication portion when the pressure in the first space exceeds a predetermined pressure.

[0013] [7] The battery pack described in any one of [1] to [6], wherein a third space for a refrigerant passage is formed between the bottom surface of the main body and the bottom cover. Effect of the Invention

[0014] According to the present technology, in a battery pack, deformation of the case when gas is discharged can be suppressed with a simple structure. [Brief description of the drawings]

[0015] [Figure 1] FIG. 2 is a perspective view of the battery pack. [Diagram 2] FIG. 2 is a perspective view of a battery pack included in the battery pack. [Diagram 3] FIG. 2 is a perspective view of a battery cell included in a battery pack. [Figure 4] FIG. 4 is a bottom view of the case body of the battery pack. [Diagram 5] 5 is a cross-sectional view of FIG. 4 . [Figure 6] FIG. 4 is a perspective view showing the vicinity of an opening of a duct. [Figure 7] 7 is a cross-sectional view taken along line VII-VII in FIG. 6. [Figure 8] 1 is a diagram showing the bottom surface of the case body, illustrating the periphery of the duct. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] Hereinafter, embodiments of the present technology will be described. Note that the same or corresponding parts are denoted by the same reference characters, and description thereof will not be repeated.

[0017] In the embodiments described below, when referring to the number, amount, etc., the scope of the present technology is not necessarily limited to the number, amount, etc., unless otherwise specified. In addition, in the following embodiments, each component is not necessarily essential to the present technology, unless otherwise specified. In addition, the present technology is not necessarily limited to those that achieve all of the effects and advantages mentioned in the present embodiment.

[0018] In this specification, the words "comprise", "include" and "have" are open-ended, i.e., when a certain configuration is included, other configurations may or may not be included.

[0019] Furthermore, when geometric terms and terms expressing positional and directional relationships, such as "parallel," "orthogonal," "45° diagonal," "coaxial," and "along" are used in this specification, these terms allow for manufacturing errors and slight variations. When terms expressing relative positional relationships, such as "upper side" and "lower side," are used in this specification, these terms are used to indicate relative positional relationships in one state, and the relative positional relationships can be inverted or rotated to any angle depending on the installation direction of each mechanism (for example, by turning the entire mechanism upside down).

[0020] In this specification, the term "battery" is not limited to lithium ion batteries, but may include other batteries such as nickel-metal hydride batteries and sodium ion batteries. In this specification, the term "electrode" may collectively refer to a positive electrode and a negative electrode.

[0021] In this specification, the term "battery cell" is not necessarily limited to a rectangular shape, and may include cells of other shapes, such as a cylindrical shape, a pouch shape, and a blade shape. Also, the "battery cell" can be mounted in hybrid electric vehicles (HEVs), plug-in hybrid electric vehicles (PHEVs), and battery electric vehicles (BEVs). However, the use of the "battery cell" is not limited to in-vehicle use.

[0022] Fig. 1 is a perspective view of a battery pack according to the present embodiment. As shown in Fig. 1, the battery pack 1 includes a case 200. An assembled battery 10 is housed in an internal space 200A (first space) of the case 200.

[0023] 1, 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) each include a plurality of battery cells aligned in the Y-axis direction (first direction) and are arranged to line up with each other in the X-axis direction (second direction).

[0024] The case 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 by a plurality of fastening parts 240 each formed of a bolt or the like.

[0025] Main body 210 and upper cover 220 form an internal space 200A of case 200. Between the bottom surface of main body 210 and bottom cover 230, a refrigerant passage 210A and an exhaust duct 210B (see FIGS. 4 and 5), which will be described later, are formed.

[0026] As shown in FIG. 1, case 200 is provided with opening 200B that connects exhaust duct 210B to the outside of case 200, inlet portion 200C for the refrigerant to refrigerant passage 210A, and outlet portion 200D for the refrigerant from refrigerant passage 210A.

[0027] Fig. 2 is a perspective view of the battery pack 10. The battery pack 10 shown in Fig. 2 includes battery cells 100 and insulating members 100A (inter-cell separators). The battery cells 100 and the insulating members 100A are arranged alternately along the Y-axis direction (first direction).

[0028] 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).

[0029] The insulating member 100A is provided between multiple battery cells 100. The insulating member 100A prevents unintended electrical conduction between adjacent battery cells 100. The insulating member 100A ensures electrical insulation between adjacent battery cells 100.

[0030] 1 is constructed by housing the battery assembly 10 in the case 200. The battery pack 1 may have a cell-to-pack structure in which a stack of battery cells 100 and insulating members 100A is directly supported by the wall of the case 200, or may have a cell-module-pack structure in which a battery module including a plurality of battery cells 100 and insulating members 100A is housed in the case 200.

[0031] Fig. 3 is a perspective view showing the battery cell 100. As shown in Fig. 3, the battery cell 100 has a rectangular shape. The battery cell 100 has an electrode terminal 110, a battery case 120, and a gas release valve 130.

[0032] The electrode terminal 110 is formed on the battery case 120. The electrode terminal 110 has a positive electrode terminal 111 and a negative electrode terminal 112 aligned along an X-axis direction (second direction) perpendicular to a Y-axis direction (first direction). The positive electrode terminal 111 and the negative electrode terminal 112 are spaced apart from each other in the X-axis direction.

[0033] The battery case 120 has a rectangular parallelepiped shape and forms the external appearance of the battery cell 100. The battery case 120 includes a case body 120A that houses an electrode assembly 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.

[0034] 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.

[0035] 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 terminals 110 are disposed on the upper surface 121. The lower surface 122 faces the upper surface 121 along the Z-axis direction.

[0036] Each of the first side surface 123 and the second side surface 124 is formed of a plane perpendicular 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 being the longitudinal direction and the Z-axis direction being the lateral direction when viewed in the Y-axis direction.

[0037] The multiple battery cells 100 are stacked such that the first side surfaces 123 and the second side surfaces 124 of the battery cells 100 adjacent to each other in the Y-axis direction face each other. As a result, the positive electrode terminals 111 and the negative electrode terminals 112 are arranged alternately in the Y-axis direction in which the multiple battery cells 100 are stacked.

[0038] The gas exhaust 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 exceeds a predetermined value due to gas generated inside the battery case 120, the gas exhaust valve 130 exhausts the gas to the outside of the battery case 120.

[0039] FIG. 4 is a bottom view of main body 210 of case 200, and FIG. 5 is a cross-sectional view taken along line VV in FIG.

[0040] As shown in FIGS. 4 and 5, a recess is formed in main body 210 facing bottom cover 230, and this recess constitutes refrigerant passage 210A and exhaust duct 210B.

[0041] Main body 210 is a cast part made of a metal such as aluminum. Top cover 220 and bottom cover 230 are plate-shaped members made of a metal such as aluminum. However, bottom cover 230 may be made of a cast part, and another recess may be provided opposite the recess of main body 210, and the two opposing recesses may be joined to form refrigerant passage 210A and exhaust duct 210B.

[0042] The refrigerant passage 210A (third space) is formed between the bottom surface of the main body 210 and the bottom cover 230. The refrigerant passage 210A is formed to extend in the Y-axis direction directly below each of the assembled batteries 11, 12, and 13. In the example of FIG. 4, a first portion 211A is formed directly below the assembled battery 11, a second portion 212A is formed directly below the assembled battery 12, and a third portion 213A is formed directly below the assembled battery 13. The refrigerant that flows into the refrigerant passage 210A from the inlet portion 200C flows through the first portion 211A, then the second portion 212A, and then the third portion 213A, and then flows out of the case 200 from the outlet portion 200D. The cooling of the battery cells 100 is promoted by the refrigerant (e.g., water) flowing directly below the assembled batteries 11, 12, and 13.

[0043] An exhaust duct 210B (second space) as an exhaust passage is formed between the bottom surface of the main body 210 and the bottom cover 230. The exhaust duct 210B communicates with the internal space 200A of the case 200 and also communicates with the outside of the case 200 via an opening 200B. A breathable breathable membrane 250 (membrane member) is provided to block the communication between the internal space 200A of the case 200 and the exhaust duct 210B. When the pressure of the internal space 200A does not exceed a predetermined pressure, the breathable membrane 250 allows air components to pass through while suppressing the intrusion of moisture into the internal space 200A. When the pressure of the first space exceeds the predetermined pressure (when it abnormally rises), the breathable membrane 250 breaks, opening the communication between the internal space 200A and the exhaust duct 210B, and facilitating the discharge of gas and the like from the internal space 200A.

[0044] The main body 210 and the bottom cover 230 are also fastened to each other at fastening parts 260 provided between the first part 211A and the second part 212A and between the second part 212A and the third part 213A. In other words, the refrigerant passages 210A are provided to extend in the Y-axis direction on both sides of the fastening parts 260 in the X-axis direction.

[0045] Fig. 6 is a perspective view showing the vicinity of opening 200B of exhaust duct 210B, and Fig. 7 is a cross-sectional view taken along line VII-VII in Fig. 6. Fig. 8 is a diagram showing the bottom surface of main body 210, showing the periphery of exhaust duct 210B.

[0046] As shown in Figures 6 to 8, opening 200B of exhaust duct 210B is located between two fastening parts 240 (first fastening part and second fastening part). When the pressure in internal space 200A of case 200 rises and gas or the like is exhausted through exhaust duct 210B, it is necessary to prevent case 200 (bottom cover 230) from deforming around opening 200B and causing exhaust from an unintended part. On the other hand, from the viewpoint of reducing manufacturing costs and saving space when mounted on a vehicle, it is also necessary to prevent the structure of case 200 from becoming complicated.

[0047] In the battery pack 1 of this embodiment, as described above, by adopting a structure in which the opening 200B of the exhaust duct 210B is provided between the two fastening portions 240, it is possible to suppress an increase in the number of parts while suppressing deformation of the case 200 and suppressing ejection from an unintended position.

[0048] Although the embodiment of the present technology has been described above, the embodiment disclosed herein should be considered as illustrative and not restrictive in all respects. The scope of the present technology is defined by the claims, and it is intended to include all modifications within the scope and meaning equivalent to the claims. [Explanation of symbols]

[0049] 1 battery pack, 10, 11, 12, 13 assembled battery, 100 battery cell, 100A insulating member, 110 electrode terminal, 111 positive electrode terminal, 112 negative electrode terminal, 120 battery case, 120A case body, 120B sealing plate, 121 upper surface, 122 lower surface, 123 first side surface, 124 second side surface, 125 third side surface, 130 gas release valve, 200 case 200A internal space, 200B opening, 200C inlet portion, 200D outlet portion, 210 main body, 210A refrigerant passage, 210B exhaust duct, 211A first portion, 212A second portion, 213A third portion, 220 upper cover, 230 bottom cover, 240, 260 fastening portion, 250 breathing membrane.

Claims

1. A plurality of battery cells; a case having a first space for housing the plurality of battery cells; the case includes a main body having a bottom surface and a bottom cover facing the bottom surface of the main body from an external side; The main body and the bottom cover are fastened to each other at a plurality of fastening portions including a first fastening portion and a second fastening portion, The main body has a recess facing the bottom cover, a second space is formed between the recess and the bottom cover, and the second space is in communication with the first space; The case has an opening that connects the second space with the outside of the case, the opening being located between the first fastening portion and the second fastening portion.

2. The battery pack of claim 1 , wherein the body is made of a cast part.

3. 3. The battery pack according to claim 1, wherein the bottom cover is made of a plate-like member.

4. 3. The battery pack according to claim 1, wherein the bottom cover has another recess facing the recess of the main body.

5. 3. The battery pack according to claim 1, further comprising a breathable film member provided to close 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 a pressure in the first space exceeds a predetermined pressure.

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

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