Battery module

Abstract

To provide a battery module capable of preventing short circuits caused by water droplets due to condensation, and the like.SOLUTION: A battery module 3 includes: a first battery group 1 having multiple cells 11; a second battery group 2 having multiple cells 11 with a safety valve 12; a cooler 20 placed between the first battery group 1 and the second battery group 2; and a protective material placed between the cooler 20 and the second battery group 2 covering a part of the second battery group 2 facing the cooler 20. The protective material is configured so that the plate thickness of the thin-walled portion facing the safety valve 12 is thinner than the plate thickness of the area other than the thin-walled portion.SELECTED DRAWING: Figure 1

Description

[Technical Field]

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

[0002] Battery modules in which multiple cells are connected using bus bars are known. For example, Japanese Patent Application Laid-Open Publication No. 2022-083610 (Patent Document 1) discloses a configuration in which bus bars that electrically connect adjacent secondary batteries have connection portions connected to external terminals and protruding portions that protrude upward from the connection portions, and voltage detection terminals are connected to the protruding portions. This configuration prevents moisture due to condensation or the like from adhering or remaining at the boundary between the bus bars and the voltage detection terminals. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2022-083610 Summary of the Invention [Problem to be solved by the invention]

[0004] When a cooler is provided in the battery module as described above, water droplets due to condensation or the like adhere to the cooler. Therefore, depending on the relative positions of the battery module and the cooler, the water droplets adhering from the cooler may migrate to the battery module, or, when multiple battery modules are installed, the water droplets may migrate to other battery modules. As a result, the adhering water droplets may cause short circuits between bus bars or cells in the battery module.

[0005] The present disclosure has been made to solve the above-mentioned problems, and its purpose is to provide a battery module that suppresses short circuits caused by water droplets resulting from condensation or the like. [Means for solving the problem]

[0006] A battery module according to an aspect of the present disclosure includes a first battery group including a plurality of cells, a second battery group including a plurality of cells each having a safety valve, a cooler provided between the first battery group and the second battery group, and a protective member covering a portion of the second battery group facing the cooler. The protective member is configured so that a thickness of a predetermined first region facing the safety valve is thinner than a thickness of a second region other than the first region.

[0007] In this way, the protective member can prevent water droplets that have formed on the cooler due to condensation or the like from moving to the second battery module. Furthermore, since the plate thickness of the first region facing the safety valve is configured to be thinner than the plate thickness of the second region, even if the gas pressure increases when the gas is released from the safety valve to the outside of the cell, an opening is more likely to be formed in the first region, allowing the gas from the safety valve to be released to the outside of the battery module in a predetermined direction.

[0008] In one embodiment, the first group of batteries is installed above the second group of batteries, and the cooler is installed below the first group of batteries.

[0009] In this way, even if water droplets that have formed on the cooler due to condensation or the like drip, the protective member can prevent them from adhering to the second battery module.

[0010] In yet another embodiment, the protective member is provided with a guide member that forms a flow path for the gas from the safety valve to the first region. The guide member is configured to have a thickness greater than the thickness of the first region.

[0011] In this way, when gas inside the cell is released to the outside of the cell through the safety valve, the pressure of the gas can be applied to the first region, making it easier to form an opening such as a crack in the first region, and therefore the gas from the safety valve can be released to the outside of the battery module in a predetermined direction. [Effects of the Invention]

[0012] According to the present disclosure, it is possible to provide a battery module that suppresses short circuits caused by water droplets due to condensation or the like. [Brief explanation of the drawings]

[0013] [Figure 1] 1A and 1B are diagrams for explaining the configuration of a battery module according to the present embodiment. [Figure 2] FIG. 2 is a diagram illustrating an example of a configuration of a protection member. [Figure 3] FIG. 10 is a diagram showing an example of the positional relationship between a cooler, a protective member, and a second battery group. [Figure 4] 10A and 10B are diagrams for explaining the function of the protective member when gas is generated from the safety valve. [Figure 5] 10A and 10B are diagrams for explaining the function of the protective member when the pressure of the gas released from the safety valve increases. DETAILED DESCRIPTION OF THE INVENTION

[0014] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. In the drawings, the same or corresponding parts are designated by the same reference numerals, and description thereof will not be repeated.

[0015] The configuration of a battery module 3 according to this embodiment will be described below. FIG. 1 is a diagram illustrating the configuration of a battery module 3 according to this embodiment. The battery module 3 is configured, for example, by combining a plurality of battery groups. The battery module 3 may be used, for example, as a stationary power storage device or as an in-vehicle power storage device. In this embodiment, the battery module 3 will be described as including, for example, a first battery group 1, a second battery group 2, and a cooler 20, as shown in FIG. 1.

[0016] Both the first battery group 1 and the second battery group 2 are composed of a plurality of cells. In this embodiment, the first battery group 1 and the second battery group 2 are each composed of the same number of stacked cells. In the following explanation, an example of the configuration of the second battery group 2 will be described as a representative example, but since the configuration of the first battery group 1 is similar to the configuration of the second battery group 2, detailed explanation thereof will not be repeated.

[0017] The second battery group 2 is formed by stacking a predetermined number of cells 11. The cells 11 are rechargeable secondary battery cells, and secondary batteries include, for example, lithium-ion secondary batteries and nickel-metal hydride secondary batteries. The cells 11 have, for example, a rectangular exterior. A safety valve 12, a positive terminal 13, and a negative terminal 14 are provided on the top surface of the cell 11. The multiple cells 11 are stacked, for example, such that the positive terminal 13 of any one cell 11 and the negative terminal 14 of the cell 11 adjacent to that cell 11 are aligned in the stacking direction. The positive terminal 13 of any one cell 11 and the negative terminal 14 of the cell 11 adjacent to that cell 11 are electrically connected by a bus bar 15. Therefore, except for the cell 11 at one end in the stacking direction and the cell 11 at the other end, the positive terminal 13 of each cell 11 is electrically connected to the negative terminal 14 of the adjacent cell 11 on one side using a bus bar 15, and the negative terminal 14 of each cell 11 is electrically connected to the positive terminal 13 of the adjacent cell 11 on the other side using a bus bar 15. The positive terminal 13 of each cell 11 at one end in the stacking direction is electrically connected to the negative terminal 14 of the adjacent cell 11 using a bus bar 15, and the negative terminal 14 is connected to the positive terminal of another battery group or an electrical load. The negative terminal 14 of each cell 11 at the other end in the stacking direction is electrically connected to the positive terminal 13 of the adjacent cell 11 using a bus bar 15, and the positive terminal 13 is connected to the negative terminal of another battery group or an electrical load. The second battery group 2 includes a housing 10 that fixes the relative positions of the multiple cells 11 and is configured to have a rectangular shape as a whole. In FIG. 1, the longitudinal direction of the second battery group 2 coincides with the stacking direction of the cells 11.

[0018] A cooler 20 is provided below the first battery group 1. The cooler 20 is, for example, a heat exchanger for exchanging heat with the first battery group 1. The cooler 20 is, for example, configured with a heat sink and cooling fins. In addition to the heat sink and cooling fins, the cooler 20 may further include a cooling medium, a medium passage through which the cooling medium flows, and a pump for circulating the cooling medium. The cooling medium may be a gas or a liquid. FIG. 1 shows the first battery group 1 positioned directly above the second battery group 2. For convenience of explanation, FIG. 1 shows the first battery group 1 and the second battery group 2 spaced apart from each other, but the first battery group 1 and the second battery group 2 are actually positioned so as to maintain an appropriate distance between them as a battery module 3.

[0019] In the battery module 3 configured as described above, water droplets due to condensation or the like may adhere to the cooler 20. When the cooler 20 uses a cooling medium, water droplets due to condensation or the like are particularly likely to adhere to the cooler 20. Therefore, depending on the relative positions of the second battery group 2 and the cooler 20, water droplets adhering from the cooler 20 may move to the second battery group 2. More specifically, when the cooler 20 is provided directly above the second battery group 2 as in the present embodiment, if water droplets adhering to the cooler 20 due to condensation or the like fall onto the second battery group 2. As a result, water droplets may penetrate between the bus bars 15 or between the cells 11 of the second battery group 2, causing a short circuit.

[0020] Therefore, in this embodiment, a protective member is provided that covers the portion of the second battery group 2 that faces the cooler 20, and the protective member is configured so that the thickness of a predetermined first region that faces the safety valve 12 of the cell 11 of the second battery group 2 is thinner than the thickness of a second region other than the first region.

[0021] In this way, the protective member can prevent water droplets adhering to the cooler 20 from moving to the second battery group 2. Furthermore, when gas inside the cells 11 is released to the outside of the cells 11 through the safety valve 12, an opening is more likely to be formed in a predetermined area due to the pressure of the gas, so that the gas from the safety valve 12 can be released to the outside of the second battery group 2 in a predetermined direction.

[0022] Fig. 2 is a diagram showing an example of the configuration of the protective member 30. The protective member 30 is made of an insulating material such as resin. As shown in Fig. 2, the protective member 30 has a shape that covers the entire upper surface on which the bus bars 15 and various terminals of the second battery group 2 are provided.

[0023] More specifically, the protective member 30 has a flat portion 31, a bent portion 32, a thin portion 33, a first guide portion 34, and a second guide portion 35.

[0024] The flat portion 31 is made of a flat member having a horizontal plane. The bent portion 32 is connected to both ends of the flat portion 31 in the width direction (the direction perpendicular to the longitudinal direction of the second battery group 2) and is made of a plate-shaped member bent in a stepped shape. One end of the bent portion 32, which is different from the end connected to the flat portion 31, is located outside the end of the second battery group 2 in the width direction. In other words, the flat portion 31 and bent portion 32 of the protective member 30 cover the entire top surface of the second battery group 2.

[0025] The thin-walled portion 33 is set in a predetermined region (corresponding to a first region) in the center of the flat portion 31. For example, when the protective member 30 is provided on the upper surface of the second battery group 2, the predetermined region is set in a position facing each of the safety valves 12 of the multiple cells 11 that make up the second battery group 2. The protective member 30 is configured so that the thickness of the thin-walled portion 33 is thinner than the thickness of the flat portion 31 in a region (corresponding to a second region) other than the predetermined region.

[0026] Each of the first and second guide portions 34 and 35 protrudes downward from the lower center of the flat portion 31. The first and second guide portions 34 and 35 are strip-shaped members that are continuously formed from one longitudinal end to the other. The connection portion of the first guide portion 34 with the flat portion 31 and the connection portion of the second guide portion 35 with the flat portion 31 are positioned so as to sandwich the thin portion 33. Therefore, the protruding strip-shaped members of the first and second guide portions 34 and 35 face each other. Therefore, when the protective member 30 is provided on the top surface of the second battery group 2, a space is formed that is surrounded by the thin portion 33, the first and second guide portions 34 and 35, and the top surface of the second battery group 2, including the plurality of safety valves 12.

[0027] The thickness of the thin-walled portion 33 is set by experiment, etc., so that when gas is released from the safety valve 12 and the pressure in the above-mentioned space exceeds a threshold value, a crack will appear in the thin-walled portion 33, forming a tear (opening).

[0028] The operation of the battery module 3 according to this embodiment will be described with reference to FIGS. 3, 4 and 5. FIG.

[0029] FIG. 3 is a diagram illustrating an example of the positional relationship between the cooler 20, the protective member 30, and the second battery group 2. FIG. 3 shows a cross-sectional view of the cooler 20 and the second battery group 2, taken along a plane including the vertical and width directions, with the protective member 30 attached. As shown in FIG. 3, the first battery group 1 is disposed directly above the second battery group 2, and the cooler 20 is provided on the bottom surface of the first battery group 1. As described above, the protective member 30 is provided so as to cover the entire top surface of the second battery group 2. Therefore, the cooler 20 is positioned directly above the protective member 30. With this configuration, even if water droplets due to condensation or the like adhere to the cooler 20 and drip onto the second battery group 2 below, the protective member 30 prevents the dripped water droplets from moving to the second battery group 2.

[0030] FIG. 4 is a diagram illustrating the function of the protective member 30 when gas is generated from the safety valve 12. FIG. 4 shows a cross-sectional view of the cooler 20 and the second battery group 2 with the protective member 30 installed, taken along a plane including the vertical and width directions. Gas may be generated in one of the cells 11 due to deterioration or other reasons, causing an increase in the internal pressure of the cell 11. When the internal pressure of the cell 11 reaches or exceeds a certain value, the gas is released from the safety valve 12, as shown in FIG. 4. The gas released from the safety valve 12 remains in the space surrounded by the thin-walled portion 33, the first guide portion 34, the second guide portion 35, and the top surface of the second battery group 2 including the safety valve 12.

[0031] FIG. 5 is a diagram illustrating the function of the protective member 30 when the pressure of the gas released from the safety valve 12 increases. FIG. 5 shows a cross-sectional view of the cooler 20 and the second battery group 2 with the protective member 30 installed, taken along a plane including the vertical and width directions. When the pressure in the space described above exceeds a threshold value, the thin-walled portion 33 deforms and forms a tear (opening) because the thickness of the thin-walled portion 33 is thinner than the thicknesses of the two members constituting the first guide portion 34 and the second guide portion 35. This allows the gas released from the safety valve 12 to flow out to the top of the protective member 30.

[0032] As described above, in the battery module 3 according to the present embodiment, the protective member 30 can prevent water droplets adhering to the cooler 20 from adhering to the second battery group 2. Furthermore, since the thickness of the thin-walled portion 33 facing the safety valve 12 is configured to be thinner than the thickness of the region other than the thin-walled portion 33, when gas is released from the safety valve 12 to the outside of the cells 11, an opening is more likely to be formed in the thin-walled portion 33 due to the pressure of the gas. This allows the gas from the safety valve 12 to be released directly above the protective member 30. Therefore, a battery module can be provided that prevents short circuits caused by water droplets due to condensation or the like.

[0033] Furthermore, since the first battery group 1 is installed above the second battery group 2 and the cooler 20 is installed below the first battery group 1, the protective member 30 can prevent water droplets adhering to the cooler 20 from dripping and moving to the second battery group 2.

[0034] Furthermore, the protective member 30 is provided with a first guide portion 34 and a second guide portion 35 that form a gas flow path from the safety valve 12 to the thin-walled portion 33, and the thicknesses of the first guide portion 34 and the second guide portion 35 are configured to be thicker than the thickness of the thin-walled portion 33. This allows the pressure of the gas to act on the thin-walled portion 33 when the gas is released from the safety valve 12 to the outside of the cells 11. This makes it easier to form an opening in the thin-walled portion 33. As a result, the gas from the safety valve 12 can be released in a predetermined direction of the second battery group 2 (directly above the protective member 30).

[0035] Modifications will be described below. In the above-described embodiment, the first battery group 1 is provided directly above the second battery group 2, and the cooler 20 is provided on the bottom surface of the first battery group 1. However, the positional relationship between the first battery group 1, the second battery group 2, and the cooler 20 is not limited to this positional relationship.

[0036] Any positional relationship is acceptable as long as, without the protective member 30, water droplets adhering to the cooler 20 can move to the upper surface of the second battery group 2. Therefore, for example, the first battery group 1 and the second battery group 2 may be arranged horizontally, with the cooler 20 provided between the first battery group 1 and the second battery group 2. In such a configuration, even if water droplets adhere to the cooler 20 and are scattered toward the second battery group 2 by wind from traveling or cooling air, the bent portion 32 at the end of the protective member 30 will prevent the water droplets from moving to the upper surface of the second battery group 2.

[0037] Furthermore, in the above-described embodiment, it has been described that the thin-walled portion 33 is set as a continuous area along the stacking direction from a position directly above the safety valve 12 of the cell 11 at one end of the stacking direction among the multiple cells 11 included in the second battery group 2 to a position directly above the safety valve 12 of the cell 11 at the other end. However, for example, it is also possible to set as the thin-walled portion 33 of the protective member 30 an area of ​​a predetermined shape (for example, circular or rectangular) directly above each safety valve 12 of the multiple cells 11 included in the second battery group 2.

[0038] Furthermore, in the above embodiment, the plate thickness of the thin-walled portion 33 is made thinner than the plate thickness of the other areas to make it easier to form an opening, but, for example, the plate thickness of the thin-walled portion 33 may be made thinner than the plate thickness of the other areas, and the thin-walled portion 33 may be made of a separate member made of the same material as the other areas, or a separate member made of a different material. In this way, it becomes possible to reuse the protective member 30 by replacing the member of the thin-walled portion 33 with a new member after a tear or the like is formed.

[0039] Furthermore, in the above-described embodiment, the battery module 3 has been described as including the first battery group 1, the second battery group 2, and the cooler 20 as an example. However, the battery module 3 may further include battery groups other than the first battery group 1 and the second battery group 2, or may further include coolers other than the cooler 20. In this case, the protective member 30 may be provided on the battery group (including the second battery group 2) to which water droplets adhering to each cooler may move. In this way, it is possible to prevent water droplets from adhering to the battery group on which the protective member 30 is provided.

[0040] Furthermore, in the above embodiment, the space formed by the first guide portion 34, the second guide portion 35, the thin portion 33 of the protective member 30, and the upper surface of the second battery group 2 is described as being connected in the stacking direction (longitudinal direction). However, the space may be divided into multiple spaces by a partition plate. For example, a partition plate may be provided between the first guide portion 34 and the second guide portion 35 of the protective member 30 to separate the space directly above the safety valve 12 of one of the cells 11 from the space directly above the safety valve 12 of an adjacent cell 11. In this way, when gas is generated from the safety valve 12 of one of the multiple cells 11, an opening is formed in the thin portion 33 directly above, making it possible to quickly identify the cell 11 from which gas has been generated.

[0041] The above-described modifications may be implemented in whole or in part in appropriate combination. The embodiments disclosed herein should be considered to be illustrative in all respects and not restrictive. The scope of the present invention is defined by the claims, not by the above description, and is intended to include all modifications within the meaning and scope of the claims. [Explanation of symbols]

[0042] 1 first battery group, 2 second battery group, 3 battery module, 10 housing, 11 cell, 12 safety valve, 13 positive terminal, 14 negative terminal, 15 bus bar, 20 cooler, 30 protective member, 31 flat portion, 32 bent portion, 33 thin portion, 34 first induction portion, 35 second induction portion.

Claims

1. a first battery group including a plurality of cells; a second battery group including a plurality of cells each having a safety valve; a cooler provided between the first battery group and the second battery group; a protective member covering a portion of the second battery group facing the cooler, The protective member is configured such that a thickness of a predetermined first region facing the safety valve is thinner than a thickness of a second region other than the first region.

2. the first battery group is installed above the second battery group, The battery module according to claim 1 , wherein the cooler is installed below the first battery group.

3. the protective member is provided with a guide member that forms a gas flow path from the safety valve to the first region, The battery module according to claim 1 , wherein the guide member is configured to have a thickness greater than a thickness of the first region.

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