Battery pack

Abstract

The utility model relates to a battery pack which is carried on a vehicle and is provided with a plurality of battery units and a middle part, the plurality of battery units are arranged along the arrangement direction and are restrained along the arrangement direction, and the middle part is arranged between at least one group of adjacent battery units in the plurality of battery units and is used for supporting the battery units. And an elastic member having two plates facing each other in contact with the group of adjacent battery cells, and an elastic body connecting the two plates, the elastic body being made of a thermoplastic resin and generating an elastic force along the arrangement direction. As a result, when one battery cell in the battery pack is overheated, it is possible to prevent chain overheating without increasing the width of the entire battery pack.

Description

Technical Field

[0001] The utility model relates to a battery pack mounted on a vehicle. Background Art

[0002] Patent Document 1 discloses a battery pack capable of suppressing the development of chain heat generation between battery cells.

[0003] Patent Document 1: Japanese Patent Application Publication No. 2020-77493

[0004] One of the technical problems related to batteries is overheating caused by abnormal heat generation of battery cells due to degradation or short circuit, etc. Furthermore, the occurrence of chain overheating that is transmitted to surrounding cells is also a technical problem.

[0005] As a countermeasure against chained overheating, for example, in Patent Document 1, a restraining plate made of a thermoplastic resin is provided between battery cells, and an elastic body is provided inside the restraining plate. When the temperature rises too high, the restraining plate melts, and the elastic body inside the restraining plate is exposed. The elastic force (repulsive force) of the exposed elastic body is used to keep the battery cells away from each other, thereby preventing chained overheating.

[0006] However, in order for the above mechanism to work, the elastic force that moves the battery cells away from each other must be greater than the restraining force that restrains the entire battery pack. Meeting this condition means that the width of the entire battery pack is also increased.

[0007] For example, when multiple battery packs described in Patent Document 1 are mounted on an electric vehicle, it is necessary to ensure space for the battery packs as a whole. If there is no such space, the battery packs will be constrained when overheating occurs, and the battery cells cannot be moved away from each other. As a result, it is difficult to prevent chain overheating. In addition, ensuring space means that the number of batteries that can be mounted is reduced. Utility Model Content

[0008] In view of the above situation, the technical problem to be solved by the present invention is how to prevent chain overheating in a battery cell in a battery pack without increasing the width of the battery pack as a whole.

[0009] The utility model relates to a battery pack mounted on a vehicle. The battery pack comprises a plurality of battery cells and an intermediate component. The plurality of battery cells are arranged along an arrangement direction and are constrained along the arrangement direction. The intermediate component is arranged between at least one group of adjacent battery cells among the plurality of battery cells, and comprises two opposite plates and an elastic body connecting the two plates. The two opposite plates are connected to a group of adjacent battery cells. The elastic body is composed of a thermoplastic resin and generates an elastic force along the arrangement direction.

[0010] The elastomer composed of thermoplastic resin receives heat from the plate that has become hot due to overheating, and thus plasticizes and loses its load-bearing function. On the other hand, the battery pack is constrained by a certain restraining force. The battery cell expands due to the high temperature, but the space between the two plates can be used to absorb the dimensional change of the battery cell that has become hot. That is, the two opposing plates are close to each other, but the contact between the two is avoided or suppressed. Therefore, direct heat conduction from the battery cell that has become hot to the battery cell adjacent to the battery cell can be suppressed, and the change in the width of the entire battery pack can be avoided or suppressed. Therefore, the battery loading capacity of the vehicle can be increased in a safe way.

[0011] Furthermore, the heat resistance of the elastomer only needs to be such that it plasticizes at an excessively high temperature, so it is not necessary to exert an elastic force equal to or greater than the restraining force at an excessively high temperature as in Patent Document 1. This lowers the criteria for selecting materials and can reduce costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 A three-dimensional diagram of a battery pack.

[0013] Figure 2A and Figure 2B It is a schematic diagram for explaining the detailed structure of the intermediate component and its effect.

[0014] Figure 3A and Figure 3B It is a schematic diagram showing a modified example of the intermediate member. DETAILED DESCRIPTION

[0015] The embodiments of the present invention will be described with reference to the accompanying drawings.

[0016] Figure 1 1 is a perspective view of a battery pack 1. In this figure, a plurality of battery cells 10 are arranged along an arrangement direction X. An intermediate component 20 is arranged between each battery cell 10A to 10F. Here, the intermediate component 20 is used as a means to solve the technical problem proposed in the utility model. The detailed structure of the intermediate component 20 will be described later. Figure 1 In the embodiment, the intermediate member 20 is used between the battery cell 10C and the battery cell 10D. The restraining plates 31 are respectively provided at both ends of the arrangement so as to be in contact with the battery cells 10A and 10F located at the ends of the arrangement. The restraining plates 31 are connected and fixed to each other by restraining bands 32. The restraining plates 31 and the restraining bands 32 are joined by mechanical joining using bolts or the like. That is, the battery pack 1 is configured such that the arrangement body including the plurality of battery cells 10 and the intermediate member 20 is pressed along the arrangement direction X by the restraining plates 31 and the restraining bands 32.

[0017] For example, by mounting a plurality of battery packs 1 on a vehicle, the vehicle can be used as a power source for electric vehicles such as BEV, PEV, and HEV. The battery cell is a chargeable and dischargeable secondary battery, such as a lithium ion secondary battery.

[0018] Figure 2A and Figure 2B It is a schematic diagram for explaining the detailed structure and effect of the intermediate member 20. Figure 2A This is the state before the battery cell 10 is overheated. The intermediate component 20 includes two plates 21 and an elastic body 22. The plates 21 are made of metal and are arranged in contact with the battery cells 10 and face each other. The elastic body 22 is arranged in such a way that its length direction is along the arrangement direction, and connects the two plates 21. The material of the elastic body 22 is a thermoplastic resin. The shape of the elastic body 22 is, for example, a spring shape.

[0019] The elastic body 22 plays a role in pushing the plate 21 outward, that is, toward the restraining plate 31 . That is, the battery cell 10 is fixed so as to be pressed against the restraining plate 31 by the elastic body 22 .

[0020] Figure 2B This shows that the battery cell 10A has overheated. The heat generated in the battery cell 10A is transferred to the adjacent battery cell 10B, further to the battery cell 10C, and then to the plate 21A. In addition, the battery cells 10A to 10C expand as the temperature rises.

[0021] The elastomer 22 made of thermoplastic resin plasticizes under the heat received from the high-temperature plate 21A and loses its load-bearing function. On the other hand, although the restraining plate 31 and the restraining belt 32 are affected by the high temperature, they have a certain restraining force. Therefore, the dimensional changes caused by the expansion of the battery cells 10A to 10C are mainly absorbed between the plate 21A and the plate 21B. Therefore, even after the temperature is raised, it is easy to form a space between the plates 21, and it is difficult to generate direct heat conduction to the battery cell 10D on the opposite side. This can prevent the chain overheating of the battery pack 1 and help improve the overall safety of the vehicle.

[0022] The dimensional changes caused by the expansion of the battery cells 10A to 10C are absorbed mainly between the plates 21A and 21B, which means that the width of the entire battery pack 1 (the length along the arrangement direction X) is not easy to change. Therefore, even if a plurality of battery packs 1 are mounted on a vehicle, adjacent battery packs 1 are not easy to contact each other, that is, heat is not easy to transfer. Therefore, it can be said that the battery loading capacity of the vehicle can be increased in a safe way.

[0023] Figure 3A and Figure 3B It is a schematic diagram showing a modified example of the intermediate member 20 . Figure 3AThe figure shows the state of the battery pack 1 before overheating. In the battery pack 1 shown in the figure, the plate 21 has a convex portion 21a.

[0024] Figure 3B 2 shows the state of the battery pack 1 after the temperature is increased. As in the above example, the elastic body 22 is plasticized and the battery cells 10A to 10C expand. Here, the expansion amount of the battery cells 10A to 10C is considered to be greater than Figure 2B When the plates 21 are large and opposite to each other, they are in contact with each other. As shown in the figure, when the plates 21 have convex parts 21a, the convex parts 21a are in contact with each other, and the path of heat conduction is a limited path through the convex parts 21a. On the other hand, when there are no convex parts 21a, the plates 21 are in contact with each other over the entire surface, which easily causes heat conduction, resulting in a high risk of chain overheating. Therefore, by having convex parts 21a, it is possible to reduce heat conduction when the plates 21 are in contact with each other, which helps prevent chain overheating.

Claims

1. A battery pack mounted on a vehicle, characterized in that: Having a plurality of battery cells and an intermediate component, The plurality of battery cells are arranged along an arrangement direction and are constrained along the arrangement direction. The intermediate component is disposed between at least one group of adjacent battery cells among the plurality of battery cells, and has two plates facing each other and an elastic body connecting the two plates. The two plates are connected to the group of adjacent battery cells, The elastic body is made of thermoplastic resin and generates elastic force along the arrangement direction.

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