Battery pack protection structure

Abstract

To provide technology that protects the battery pack from impacts from the road surface. [Solution] The battery pack protection structure includes at least a carbon fiber reinforced plastic member and a glass fiber reinforced plastic member. If the battery pack protection structure includes a metal frame, the fiber-reinforced plastic member is incorporated into a space provided within the metal frame.

Description

Technical Field

[0001] The present disclosure relates to a battery pack protection structure for protecting an in-vehicle battery pack.

Background Art

[0002] Patent Document 1 discloses a battery pack protection structure for an electric vehicle. The battery pack protection structure is made of a plastic composite material in which a plastic base material and reinforcing fibers are mixed.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] Since the battery pack mounted on an electric vehicle is often housed in the lower part of the vehicle body, it is likely to be impacted from the road surface side by falling objects (stones, metal pieces, etc.) on the road surface.

[0005] One object of the present disclosure is to provide a technique for protecting a battery pack from an impact applied from the road surface side.

Means for Solving the Problems

[0006] A first aspect relates to a battery pack protection structure for protecting an in-vehicle battery pack. The battery pack protection structure includes at least a carbon fiber reinforced plastic member and a glass fiber reinforced plastic member.

[0007] A second aspect relates to a battery pack protection structure for protecting an in-vehicle battery pack. The battery pack protection structure includes a metal frame and a fiber reinforced plastic member. The fiber-reinforced plastic component is incorporated into a space provided within the metal frame. [Effects of the Invention]

[0008] From the first perspective, by using glass fiber reinforced plastic members, which have excellent rigidity, and carbon fiber reinforced plastic members, which have excellent lightweight properties, both improvements in structural performance and weight reduction can be obtained for the battery pack protection structure.

[0009] From a second perspective, a metal frame and fiber-reinforced plastic components are combined. This allows for the use of conventional metalworking techniques, minimizing the need for additional specialized equipment for plastic molding. Furthermore, the appropriate use of fiber-reinforced plastic components improves the structural performance of the battery pack protection structure. [Brief explanation of the drawing]

[0010] [Figure 1] This is a schematic diagram of the battery pack installed in the vehicle. [Figure 2] This is a cross-sectional view showing an example of the configuration of a battery pack protection structure. [Figure 3] This is a cross-sectional view showing an example of a battery pack protection structure including a metal frame. [Figure 4] This is a cross-sectional view showing another example of a battery pack protection structure including a metal frame. [Modes for carrying out the invention]

[0011] Embodiments of this disclosure will be described with reference to the attached drawings.

[0012] 1. Battery pack for vehicles Figure 1 is a schematic diagram of a battery pack 10 mounted on a vehicle 1. The battery pack 10 is used as a power source for electric vehicles such as BEVs, PHEVs, and HEVs. In the drawing, the X direction indicates the direction in which the vehicle 1 moves forward. The Y direction indicates the left direction when viewing the vehicle 1 from above. The Z direction indicates the upward direction of the vehicle 1. These directions are set for the convenience of explanation and do not necessarily limit the embodiment. For example, in Figure 1, the battery cells 30, which will be described later, are stacked along the Y direction. However, the actual loading direction is not limited to the Y direction and may be, for example, the X direction.

[0013] The battery pack 10 comprises one or more battery stacks 20 (hereinafter simply referred to as battery stacks 20). Each battery stack 20 is composed of multiple battery cells 30 (also called single cells) stacked on top of each other. The battery cells 30 are rechargeable secondary batteries, such as lithium-ion secondary batteries. The battery pack 10 also typically includes a case (a so-called battery case) that covers the battery stacks 20. The battery case (not shown in the figure) is made of aluminum alloy or steel and serves to protect the battery cells 30 from external loads. The vehicle 1 is driven by the rotation of a motor powered by electricity stored in the battery pack 10 (more specifically, the battery cells 30). Generally, the battery pack 10 is housed in the underside (under the floor) of the vehicle 1.

[0014] 2. Battery pack protection The battery pack 10 of vehicle 1 needs to be adequately protected from external impacts. For example, an impact can cause a short circuit, which can trigger various thermal decomposition reactions inside the battery cells 30. As a result, the temperature continues to rise, posing a risk of ignition. In particular, lithium-ion secondary batteries commonly used in electric vehicles contain flammable electrolytes, so measures to suppress the risk of ignition are necessary. Therefore, protecting the battery pack 10 from impacts and preventing phenomena that trigger temperature increases, such as short circuits, is an essential consideration for enhancing the safety of vehicle 1.

[0015] As mentioned above, since the battery pack 10 is often housed under the floor of the vehicle 1, it is especially important to protect the battery pack 10 from impacts to the underside of the vehicle (i.e., impacts applied in the Z direction from the road surface). Impacts to the underside of the vehicle occur, for example, when the vehicle 1 bounces up objects (metal fragments, stones, etc.) on the road surface, and these objects hit the underside of the vehicle. Therefore, in this embodiment, a structure for protecting the battery pack 10 from impacts to the underside of the vehicle (battery pack protection structure 40) will be described in detail.

[0016] Figure 2 is a cross-sectional view showing an example of the configuration of the battery pack protection structure 40. The battery pack protection structure 40 includes a fiber-reinforced plastic member 42. Fiber-reinforced plastics (FRP) are composite materials of resin plastic and fiber material, and have high strength and high rigidity. Examples of resin plastics include polyester resin, epoxy resin, vinyl ester resin, phenolic resin, etc. Examples of fiber material include glass fiber, aramid fiber, carbon fiber, Zylon fiber, polyethylene fiber, boron fiber, etc. Hereinafter, "fiber-reinforced plastic member 42" will be referred to as "FRP member 42".

[0017] Specific examples of FRP members 42 include carbon fiber reinforced plastic members 42c and glass fiber reinforced plastic members 42g. Carbon fiber reinforced plastics (CFRP) are fiber-reinforced plastics in which carbon fibers are used as the fiber material. Glass fiber reinforced plastics (GFRP) are fiber-reinforced plastics in which glass fibers are used as the fiber material. Hereinafter, "carbon fiber reinforced plastic member 42c" and "glass fiber reinforced plastic member 42g" will be referred to as "CFRP member 42c" and "GFRP member 42g," respectively.

[0018] Generally, the GFRP member 42g has high rigidity but a large weight compared to the CFRP member 42c. That is, when the GFRP member 42g with excellent rigidity is used in the battery pack protection structure 40, the weight of the entire vehicle body tends to increase. The increase in vehicle body weight can shorten the cruising range or accelerate tire wear. Therefore, in the battery pack protection structure 40, if a lighter CFRP member 42c is used in combination with the GFRP member 42g, the effects of both improving the rigidity by the GFRP member 42g and reducing the weight by the CFRP member 42c can be obtained.

[0019] In FIG. 2, the GFRP member 42g is disposed on the side closer to the road surface (the side farther from the battery pack 10) than the CFRP member 42c. In other words, the CFRP member 42c is disposed on the side closer to the battery pack 10 (the side farther from the road surface) than the GFRP member 42g. In this arrangement, since the GFRP member 42g exists at the portion directly receiving the impact from the road surface, the effect of improving the impact resistance performance is high. Also, on the battery pack 10 side, since it does not directly receive the impact, a lighter CFRP member 42c is disposed. That is, with the arrangement as shown in FIG. 2, the effects of both improving the rigidity and reducing the weight are particularly显著地发挥出来.

[0020] The battery pack protection structure 40 may include a metal frame 41. FIG. 3 is a cross-sectional view showing a configuration example of the battery pack protection structure 40 including the metal frame 41. Typically, the metal frame 41 is made of steel, an aluminum alloy, or the like. The metal frame 41 forms a plurality of layers, and a space is provided between each layer. The FRP member 42 is disposed so as to be incorporated into the space provided in the metal frame 41. The FRP member 42 is manufactured in a shape that can fit into the space of the metal frame 41.

[0021] The effect of combining the metal frame 41 and the FRP member 42 is explained as follows. As shown in Patent Document 1, when the entire battery pack protection structure is made of plastic, special equipment for plastic molding is required. On the other hand, the metal frame 41 can be manufactured using conventional metal processing technology. In other words, by utilizing conventional technology and minimizing the need for additional special equipment, the structural performance of the battery pack protection structure 40 can be improved by using the FRP member 42 in appropriate places. The type of FRP member 42 in this case is not particularly limited. That is, it is not necessarily required to use CFRP member 42c or GFRP member 42g.

[0022] Figure 4 is a cross-sectional view showing another configuration example of the battery pack protection structure 40 including the metal frame 41. Figure 4 shows an example in which the FRP member 42 in Figure 3 includes a CFRP member 42c and a GFRP member 42g. In other words, Figure 4 can be said to be a combination of the examples in Figures 2 and 3. In this case as well, as shown in the figure, by arranging the GFRP member 42g on the road surface side and the CFRP member 42c on the battery pack 10 side, the effects of both increased rigidity and weight reduction are particularly pronounced. [Explanation of symbols]

[0023] 1: Vehicle, 10: Battery pack, 20: Battery stack, 30: Battery cell, 40: Battery pack protection structure, 41: Metal frame, 42: Fiber-reinforced plastic component, 42c: Carbon fiber-reinforced plastic component, 42g: Glass fiber-reinforced plastic component

Claims

1. A battery pack protection structure that protects a battery pack installed in a vehicle, Includes at least carbon fiber reinforced plastic members and glass fiber reinforced plastic members Battery pack protection structure.

2. A battery pack protection structure according to claim 1, The glass fiber reinforced plastic member is positioned further away from the battery pack than the carbon fiber reinforced plastic member. Battery pack protection structure.

3. A battery pack protection structure that protects a battery pack installed in a vehicle, Metal frame, Fiber-reinforced plastic components and Includes, The fiber-reinforced plastic member is incorporated into a space provided within the metal frame. Battery pack protection structure.

4. A battery pack protection structure according to claim 3, The fiber-reinforced plastic member includes at least a carbon fiber-reinforced plastic member and a glass fiber-reinforced plastic member. Battery pack protection structure.

5. A battery pack protection structure according to claim 4, The glass fiber reinforced plastic member is positioned further away from the battery pack than the carbon fiber reinforced plastic member. Battery pack protection structure.

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