Battery module

Abstract

To provide a battery module capable of suppressing an electrical short circuit caused by ejection from a battery cell.SOLUTION: A battery includes a plurality of battery cells arranged in a first direction and a cover member provided on the plurality of battery cells. Each of the plurality of battery cells includes a housing having a gas release valve and an electrode terminal provided on the housing. The cover member includes a first region and a second region having a strength lower than that of the first region. The first region is located above at least one of the electrode terminals. The second region is located above at least one of the gas release valves and includes a notch formed in the cover member.SELECTED DRAWING: Figure 4

Description

[Technical field]

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

[0002] There is a conventional technique for opening a part of an exterior can to release internal gas when pressure inside the exterior can of a battery cell constituting a battery module increases.Similarly, there is a conventional technique for opening a part of a pack case to release internal gas when pressure inside a battery pack case increases. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2012-104471 A [Patent Document 2] JP 2014-041841 A [Patent Document 3] JP 2014-060165 A Summary of the Invention [Problem to be solved by the invention]

[0004] In a battery module having a structure in which a cover member is provided over multiple battery cells, when part of the exterior can is opened due to an increase in pressure inside the exterior can of the battery cells, the cover member is blown off by gas ejected from inside the exterior can, exposing the bus bars, voltage detection wires, etc. If metal-containing ejected material from inside the exterior can adheres to the exposed bus bars, voltage detection wires, etc., an electrical short circuit may occur.

[0005] An object of the present technology is to provide a battery module that can suppress electrical short circuits caused by ejection from a battery cell. [Means for solving the problem]

[0006] The present technology provides the following battery module. [1] A battery module comprising: a plurality of battery cells arranged in a first direction; and a cover member provided on the plurality of battery cells, each of the plurality of battery cells including a housing having a gas exhaust valve and an electrode terminal provided on the housing; the cover member including a first region and a second region having a lower strength than the first region, the first region being located over at least one electrode terminal, the second region being located over at least one gas exhaust valve, and including a cutout portion formed in the cover member.

[0007] [2] The battery module described in [1], wherein the second region extends in the first direction so as to be located above at least a plurality of the gas release valves.

[0008] [3] The battery module described in [1] or [2], wherein the cutout portion is formed so as to surround an upper region of the gas release valve. Effect of the Invention

[0009] According to the present technology, by providing a second region with a relatively low strength on the gas exhaust valve in a cover member provided on a plurality of battery cells, the cover member located in the second region can be selectively destroyed when gas is exhausted, and the first region located on the electrode terminal can be protected. As a result, electrical short circuits caused by ejection from the battery cells can be suppressed. [Brief description of the drawings]

[0010] [Figure 1] FIG. 2 is a diagram showing a basic configuration of a battery module. [Diagram 2] FIG. 2 is a perspective view showing a battery cell. [Diagram 3] FIG. 2 is a perspective view showing a state in which a wiring module is provided on a battery module. [Figure 4] FIG. 2 is a top view of the battery module. [Diagram 5] 1A and 1B are diagrams illustrating a state in which gas is discharged from a battery cell. [Figure 6] 6 is a diagram showing a schematic view of the periphery of a second region of the plate member. FIG. [Figure 7] FIG. 11 is a perspective view showing a modified example of the second region. [Figure 8] 8 is a cross-sectional view showing a second region shown in FIG. 7. [Figure 9] FIG. 11 is a cross-sectional view (part 1) showing a further modified example of the second region of the plate member. [Figure 10] FIG. 11 is a cross-sectional view (part 2) showing a further modified example of the second region of the plate member. [Figure 11] FIG. 11 is a cross-sectional view (part 3) showing a further modified example of the second region of the plate member. [Figure 12] FIG. 11 is a cross-sectional view (part 4) showing a further modified example of the second region of the plate member. [Figure 13] FIG. 13 is a fifth cross-sectional view showing a further modified example of the second region of the plate member. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] 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.

[0012] 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.

[0013] 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.

[0014] 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).

[0015] 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 positive and negative electrodes. In addition, the term "electrode plate" may collectively refer to positive and negative plates.

[0016] In this specification, a "battery cell" can be mounted in a hybrid electric vehicle (HEV), a plug-in hybrid electric vehicle (PHEV), an electric vehicle (BEV), etc. However, the use of the "battery cell" is not limited to being mounted in a vehicle.

[0017] 1 is a diagram showing the basic configuration of a battery pack 1. As shown in FIG. 1, the battery pack 1 includes a battery cell 100, an end plate 200, and a restraining member 300.

[0018] The multiple battery cells 100 are arranged side by side in the Y-axis direction (first direction). This forms a stack of the battery cells 100. The battery cells 100 include electrode terminals 110. Separators (not shown) are interposed between the multiple battery cells 100. The multiple battery cells 100 sandwiched between the two end plates 200 are pressed by the end plates 200 and are restrained between the two end plates 200.

[0019] The end plates 200 are disposed on both ends of the battery pack 1 in the Y-axis direction. The end plates 200 are fixed to a base such as a case that houses the battery pack 1. The restraining members 300 connect the two end plates 200 to each other.

[0020] By fixing the restraining member 300 to the end plate 200 while a compressive force in the Y-axis direction is applied to the stack of multiple battery cells 100 and end plates 200, and then releasing the compressive force, a tensile force acts on the restraining member 300 connecting the two end plates 200. In reaction to this, the restraining member 300 presses the two end plates 200 in a direction that brings them closer to each other.

[0021] Fig. 2 is a perspective view showing the battery cell 100. As shown in Fig. 2, the battery cell 100 has a rectangular shape. The battery cell 100 has an electrode terminal 110 and a housing 120 (external can). In other words, the battery cell 100 is a rectangular secondary battery cell.

[0022] The electrode terminal 110 is formed on the housing 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.

[0023] The housing 120 has a rectangular parallelepiped shape and forms the external appearance of the battery cell 100. The housing 120 includes a case body 120A that contains an electrode body and an electrolyte (not shown), and a sealing plate 120B that seals an opening of the case body 120A. The sealing plate 120B is joined to the case body 120A by welding.

[0024] The housing 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. The housing 120 is provided with a gas exhaust valve 126.

[0025] 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.

[0026] 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 housing 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 long side direction and the Z-axis direction being the short side direction when viewed in the Y-axis direction.

[0027] 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.

[0028] Gas exhaust valve 126 is provided on top surface 121. When the temperature of battery cell 100 rises (thermal runaway) and the internal pressure of housing 120 exceeds a predetermined value due to gas generated inside housing 120, gas exhaust valve 126 exhausts the gas to the outside of housing 120.

[0029] Fig. 3 is a perspective view showing a state in which a wiring module is provided on the battery pack 1. As shown in Fig. 3, a plate member 400 is placed on the battery pack 1, and a flexible printed circuit board 500 is provided on the plate member 400. The flexible printed circuit board 500 can be electrically connected to an external device via a connector 600. A cover member 700 is provided on the plate member 400 so as to cover the flexible printed circuit board 500. Note that instead of the flexible printed circuit board 500, an electric wire or a flexible flat cable (FFC) may be used as a voltage detection line.

[0030] 4 is a top view of the battery module. As shown in FIG. 4, a cover member 700 provided on a plurality of battery cells 100 includes a first region 710 and a second region 720.

[0031] The first region 710 extends in the Y-axis direction so as to be located above the multiple electrode terminals 110. The first region 710 only needs to be formed so as to be located above at least one electrode terminal 110.

[0032] The second region extends in the Y-axis direction so as to be located above the multiple gas exhaust valves 126. The second region 720 may be formed so as to be located above at least one gas exhaust valve 126. The second region 720 is formed so as to have a lower strength than the first region 710.

[0033] 5 is a diagram showing a schematic diagram of a state in which gas is discharged from the battery cell 100. As shown in FIG. 5, when the gas discharge valve 126 is opened due to an increase in the internal pressure of the casing 120 of the battery cell 100, the gas ejected from the gas discharge valve 126 blows off the cover member 700, exposing live members such as the bus bar and the voltage detection wire. If a metal-containing ejection from inside the casing 120 adheres to the live members, an electrical short circuit may occur. These live members are electrically connected to the electrode terminal 110 of the battery cell 100, and therefore are located away from the center in the X-axis direction (second direction).

[0034] In contrast, in the battery module according to the present embodiment, in the cover member 700 provided on the plurality of battery cells 100, the second region 720 having a relatively low strength is provided on the gas release valve 126. Therefore, when gas is ejected from the gas release valve 126, the second region 720 of the cover member 700 located on the gas release valve 126 can be selectively destroyed. As a result, the first region 710 located on the electrode terminal 110 can be protected, that is, the first region 710 can be maintained on the live member. Therefore, an electrical short circuit caused by the ejection from the battery cell 100 adhering to the live member can be suppressed.

[0035] Fig. 6 is a diagram showing a schematic view of the periphery of the second region 720. In the example shown in Fig. 6, the cover member 700 has a notch 721 formed so as to surround the upper region of the gas exhaust valve 126. This allows the second region 720 to be selectively destroyed when gas is ejected from the gas exhaust valve 126, thereby protecting the first region 710 of the cover member.

[0036] Fig. 7 is a perspective view showing a modified example of second region 720. Fig. 8 is a cross-sectional view showing second region 720 shown in Fig. 7. In the modified example of Figs. 7 and 8, a substantially circular groove portion 722 is formed in cover member 700, so that second region 720 is selectively destroyed when gas is ejected from gas exhaust valve 126, thereby protecting first region 710 of the cover member.

[0037] 9 to 13 are cross-sectional views showing further modified examples of second region 420. As shown in Fig. 9 and Fig. 10, second region 720 may be configured by forming thin-walled portion 723 in a part of cover member 700, or as shown in Fig. 11, second region 720 may be configured by forming groove portion 722 having a cross-sectional shape different from that in Fig. 8.

[0038] As shown in FIG. 12, the second region 720 may be formed by removably providing a separate part 724 (lid) made of other material such as resin, rubber, etc. in a hole in the cover member 700, or as shown in FIG. 13, the second region 720 may be formed by attaching a separate part 725 made of other material such as tape, net, etc. in a hole provided in the cover member 700.

[0039] Also, the second region 720 may be formed by making the second region 720 of the cover member 700 out of a material having a relatively lower strength than the first region 710 .

[0040] 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]

[0041] 1 battery pack, 100 battery cell, 110 electrode terminal, 111 positive electrode terminal, 112 negative electrode terminal, 120 housing, 120A case body, 120B sealing plate, 121 upper surface, 122 lower surface, 123 first side surface, 124 second side surface, 125 third side surface, 126 gas exhaust valve, 200 end plate, 300 restraining member, 400 plate member, 420 second region, 500 flexible printed circuit board, 600 connector, 700 cover member, 710 first region, 720 second region, 721 cutout portion, 722 groove portion, 723 thin portion, 724, 725 separate parts.

Claims

1. A plurality of battery cells arranged in a first direction; a cover member provided on the plurality of battery cells; Each of the plurality of battery cells includes a housing having a gas release valve and an electrode terminal provided on the housing; The cover member includes a first region and a second region having a strength lower than that of the first region, the first region is located on at least one of the electrode terminals; The second region is located above at least one of the gas release valves and includes a cutout portion formed in the cover member.

2. The battery module according to claim 1 , wherein the second region extends in the first direction so as to be located above at least a plurality of the gas release valves.

3. The battery module according to claim 1 , wherein the cutout portion is formed so as to surround an upper region of the gas release valve.

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