Bottom protective plate and battery case

Abstract

To provide a bottom protective plate and a battery case with enhanced impact resistance and deformation resistance.SOLUTION: The bottom protective plate comprises an upper skin, a lower skin, and an intermediate layer. The lower skin and the upper skin are arranged with a gap therebetween. The intermediate layer is disposed so as to be sandwiched between the upper skin and the lower skin. Here, the thickness of the upper skin is greater than that of the lower skin.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] This application claims priority from a Chinese patent application bearing application number 202420589608.1 filed with the China Patent Office on March 25, 2024, and from an international application bearing application number PCT / CN2024 / 115855 filed on August 30, 2024, and incorporates all of the contents of said application by reference.

[0002] The present application relates to the field of battery technology, and in particular to a bottom protection plate and a battery box. [Background technology]

[0003] In battery technology, it is often necessary to use a bottom protection plate to protect the power battery from external foreign objects while the vehicle is in operation.

[0004] In the related art, the bottom protection plate is usually an aluminum alloy plate or a steel plate that is integrally die-cast. Summary of the Invention [Problem to be solved by the invention]

[0005] However, the manufacturing cost of the integral die-cast bottom protection plate is relatively high, and its impact resistance is relatively low, so that when subjected to an external impact, the bottom protection plate is easily deformed, which may damage the internal battery cells. [Means for solving the problem]

[0006] The present application provides a bottom protection plate, which includes an upper skin, a lower skin, and an intermediate layer, the lower skin and the upper skin being spaced apart, and the intermediate layer being sandwiched between the upper skin and the lower skin, wherein the thickness of the upper skin is greater than the thickness of the lower skin.

[0007] The present application further provides a battery box, which includes the above-mentioned bottom protective plate. [Effects of the Invention]

[0008] According to the bottom protection plate provided in the present application, the bottom protection plate has a multi-layer structure including an upper skin, an intermediate layer, and a lower skin, thereby improving the strength of the bottom protection plate and enhancing its impact resistance and deformation resistance. By making the thickness of the upper skin greater than that of the lower skin, the upper skin can better withstand deformation in the thickness direction, ensuring that the bottom protection plate meets the usage requirements. Meanwhile, the amount of material used for the lower skin can be reduced, making the entire bottom protection plate thinner and lighter. This reduces manufacturing costs while ensuring that the overall strength of the bottom protection plate meets the standard. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is a perspective schematic view of a bottom protection plate provided in an embodiment of the present application; FIG. [Figure 2] 1 is an exploded structural schematic diagram of a bottom protection plate provided in an embodiment of the present application; [Figure 3] 2 is a schematic diagram showing the structure of the bottom protection plate provided in the embodiment of the present application after being deformed under force. FIG. [Figure 4] 2 is a schematic diagram showing the structure of the bottom protection plate provided in the embodiment of the present application after being deformed under force. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0010] 1 to 4, an embodiment of the present application provides a bottom protection plate. The bottom protection plate includes an upper skin 10, a lower skin 20, and an intermediate layer 30. The lower skin 20 and the upper skin 10 are spaced apart from each other. The intermediate layer 30 is sandwiched between the upper skin 10 and the lower skin 20. Here, the thickness of the upper skin 10 is greater than the thickness of the lower skin 20.

[0011] In the present embodiment, the bottom protection plate has a multi-layer structure including the upper skin 10, the intermediate layer 30, and the lower skin 20, thereby improving the strength of the bottom protection plate and enhancing its impact resistance and deformation resistance. By making the thickness of the upper skin 10 greater than that of the lower skin 20, the upper skin 10 can better withstand deformation in the thickness direction, ensuring that the bottom protection plate meets the usage requirements, while reducing the amount of material used in the lower skin 20, making the entire bottom protection plate thinner and lighter. This reduces manufacturing costs while ensuring that the overall strength of the bottom protection plate meets the standard.

[0012] As can be seen, when the bottom protection plate is subjected to an external impact force, the impact force first acts on the lower skin 20. If the lower skin 20 can withstand deformation due to the impact force, the bottom protection plate can be prevented from being deformed by the external impact force. If the lower skin 20 is deformed due to an excessive impact force, the lower skin 20 can dissipate some of the energy of the impact force, thereby reducing the impact force received by the intermediate layer 30 and the upper skin 10 and making the intermediate layer 30 and the upper skin 10 less likely to deform. Thus, by forming a bottom protection plate with a multi-layer structure, the external impact force received can be gradually reduced, reducing the amount of deformation of the innermost upper skin 10, and improving the deformation resistance of the entire bottom protection plate, thereby preventing damage to the battery cells.

[0013] Furthermore, by making the thickness of the upper skin 10 greater than that of the lower skin 20, the intermediate layer 30 is positioned lower, allowing the intermediate layer 30 to quickly respond to resistance to deformation caused by external impact forces and ensuring resistance to deformation in the Z direction. Based on the design of a structure with non-uniform thickness, the mechanical properties of the upper skin 10, intermediate layer 30, and lower skin 20 are fully utilized, so that they have better protective performance than a bottom protection plate with a structure with uniform thickness.

[0014] In some embodiments, both the upper skin 10 and the lower skin 20 are resin layers, with a mesh fiber structure embedded within the resin layer. Embedding the mesh fiber structure within the resin layer can form a continuous fiber reinforced resin matrix composite layer. The upper skin 10 and the lower skin 20 are both continuous fiber reinforced resin matrix composite layers, and an intermediate layer 30 is sandwiched between the upper skin 10 and the lower skin 20 to form a multi-layered bottom protection plate, thereby improving the energy absorption effect of the bottom protection plate. This allows the bottom protection plate to have excellent deformation resistance in both the horizontal and thickness directions, ensuring excellent strength, as well as wear resistance and insulating and corrosion protection performance.

[0015] By using a composite material layer of continuous fiber reinforced resin to form the upper skin 10 and the lower skin 20, the upper skin 10 and the lower skin 20 have a density of 2150 kg / m 3 (kilograms per cubic meter) and has excellent tensile strength. When the bottom protection plate is deformed by an external force, the upper skin 10 and the lower skin 20 exhibit excellent deformation resistance in the XY directions (horizontal directions) and also in the Z-axis direction (thickness direction), thereby preventing damage to the battery cells.

[0016] As can be seen, when the bottom protection plate is deformed by an external force collision, the force is transmitted in the direction from the lower skin 20 to the upper skin 10, and the mesh fiber structure distributes the force in the X and Y directions, making the deformation in the Z direction relatively small. Meanwhile, since the thickness of the upper skin 10 is relatively large, the upper skin 10 can better withstand the deformation in the Z direction.

[0017] As shown in Figures 3 and 4, the bottom protection plate has a multi-layer structure consisting of an upper skin 10, an intermediate layer 30, and a lower skin 20, making the bottom protection plate more suitable for impact resistance. When the lower skin 20 receives an impact force, the mesh fiber structure of the lower skin 20 disperses the force in the X and Y directions, and the intermediate layer 30, located in the middle, has a larger impact-bearing area. The high strength and low toughness of the intermediate layer 30 itself allow the force to be quickly dispersed in the X and Y directions, causing deformation over a wider area of ​​the intermediate layer 30, but keeping the deformation in the Z direction relatively small. When the force is transmitted to the upper skin 10, the thicker mesh fiber structure of the upper skin 10 pulls the intermediate layer 30 closer, allowing it to withstand deformation of the entire bottom protection plate in the Z direction. This reduces deformation of the entire bottom protection plate in the Z direction and protects the internal structure of the battery pack. Furthermore, by making the thickness of the upper skin 10 greater than that of the lower skin 20, the intermediate layer 30 is positioned lower, allowing the intermediate layer 30 to quickly respond to resistance to deformation caused by external impact forces and ensuring resistance to deformation in the Z direction. Based on the structural design with non-uniform thickness, the material mechanical properties of the upper skin 10, intermediate layer 30 and lower skin 20 are fully utilized, so that they have better protective performance than a bottom protection plate with a structure of uniform thickness.

[0018] Here, by making the bottom protection plate, which is a multi-layer structure formed by the upper skin 10, the middle layer 30, and the lower skin 20, a flat plate structure, the bottom protection plate does not have a shape and does not have any suspension points, which prevents the vehicle from rolling over uncontrollably when a bottom collision occurs.

[0019] In some embodiments, the resin layer comprises one or more of a polyvinyl chloride layer, a polypropylene layer, a polyurethane layer, a polyamide layer, a polycarbonate layer, a polyethylene plastic layer, and a polyphenylene ether layer, where multiple resin layers are provided, and where multiple resin layers are provided in a stacked configuration; and / or the mesh fiber structure comprises one or more of a glass fiber layer, a continuous aramid fiber layer, a basalt fiber layer, and a carbon fiber layer, where multiple mesh fiber structures are provided, and where multiple mesh fiber structures are provided in a stacked configuration.

[0020] As can be seen, the continuous fiber reinforced resin matrix composite layer includes a resin layer and a mesh fiber structure embedded in the resin layer. By embedding the mesh fiber structure in the resin layer, the structure of the resin layer can be strengthened, providing the upper skin 10 and the lower skin 20 with excellent tensile strength.

[0021] Here, the mesh fiber structure includes one or more of a glass fiber layer, a continuous aramid fiber layer, a basalt fiber layer, and a carbon fiber layer. The mesh fiber structures of the upper skin 10 and the lower skin 20 may be the same type of fiber layer or different types of fiber layers. If the upper skin 10 has multiple mesh fiber structures, the multiple mesh fiber structures in the upper skin 10 may be the same type of fiber layer or different types of fiber layers, and the multiple mesh fiber structures may be stacked sequentially layer by layer. If the lower skin 20 has multiple fiber layers, the multiple fiber layers in the lower skin 20 may be the same type of fiber layer or different types of fiber layers, and the multiple mesh fiber structures may be stacked sequentially layer by layer.

[0022] Here, the resin layer includes one or more of a polyvinyl chloride layer, a polypropylene layer, a polyurethane layer, a polyamide layer, a polycarbonate layer, a polyethylene plastic layer, and a polyphenylene ether layer. The resin layers of the upper skin 10 and the lower skin 20 may be the same type of resin layer or different types of resin layers. When the upper skin 10 has multiple resin layers, the multiple resin layers in the upper skin 10 may be the same type of resin layer or different types of resin layers, and the multiple resin layers may be laminated sequentially layer by layer. When the lower skin 20 has multiple resin layers, the multiple resin layers in the lower skin 20 may be the same type of resin layer or different types of resin layers, and the multiple resin layers may be laminated sequentially layer by layer.

[0023] The material selection for the upper skin 10 and the lower skin 20 gives the upper skin 10 and the lower skin 20 excellent tensile strength and their density is 2150 kg / m 3 Furthermore, the upper skin 10 and the lower skin 20 have excellent deformation resistance in both the X and Y directions, can withstand deformation in the Z direction, and are also provided with abrasion resistance, insulation, and corrosion resistance. This reduces the weight and thickness of the upper skin 10 and the lower skin 20, thereby contributing to a thinner and lighter design for the bottom protection plate.

[0024] For example, if the resin layer is a polyvinyl chloride layer and the mesh fiber structure is a glass fiber layer, the glass fiber layer may be directly embedded in the polyvinyl chloride layer to form a continuous fiber reinforced resin composite material layer as the upper skin 10 and the lower skin 20.

[0025] For example, when the resin layer is a polyvinyl chloride layer and a polypropylene layer laminated together and the mesh fiber structure is a glass fiber layer, one glass fiber layer may be embedded in each of the polyvinyl chloride layer and the polypropylene layer to form a continuous fiber reinforced resin composite material layer, which serves as the upper skin 10 and the lower skin 20. Alternatively, one glass fiber layer may be embedded between the polyvinyl chloride layer and the polypropylene layer to form a continuous fiber reinforced resin composite material layer, which serves as the upper skin 10 and the lower skin 20.

[0026] For example, if the resin layer is a polyvinyl chloride layer and the mesh fiber structure is a laminated glass fiber layer and a carbon fiber layer, the laminated glass fiber layer and the carbon fiber layer may be embedded in the polyvinyl chloride layer to form a continuous fiber reinforced resin composite material layer, which may serve as the upper skin 10 and the lower skin 20.

[0027] For example, when the resin layer is a polyvinyl chloride layer and a polypropylene layer laminated together, and the mesh fiber structure is a glass fiber layer and a carbon fiber layer laminated together, the polyvinyl chloride layer and the polypropylene layer may each be embedded with a glass fiber layer and a carbon fiber layer laminated together to form a continuous fiber reinforced resin composite material layer, which serves as the upper skin 10 and the lower skin 20. Alternatively, the glass fiber layer and the carbon fiber layer laminated together may be embedded between the polyvinyl chloride layer and the polypropylene layer to form a continuous fiber reinforced resin composite material layer, which serves as the upper skin 10 and the lower skin 20.

[0028] In some embodiments, the thickness of the upper skin 10 is between two and three times the thickness of the lower skin 20, and / or the thickness of the upper skin 10 is between 1.2 millimeters and 3 millimeters.

[0029] By setting the thickness of the upper skin 10 to be two to three times the thickness of the lower skin 20, it is possible to ensure that the upper skin 10 has excellent resistance to deformation in the Z direction. As a result, it is possible to prevent an increase in the weight and cost of the bottom protection plate due to the upper skin 10 being too thick.

[0030] It can be seen that if the thickness of the upper skin 10 is only 1.5 times that of the lower skin 20, the deformation resistance of the upper skin 10 in the Z direction cannot meet the usage requirements, which may result in a certain safety risk for the battery pack. If the thickness of the upper skin 10 is four times that of the lower skin 20, the material usage and weight of the upper skin 10 will be relatively large, which will result in an increase in the weight, cost, and thickness of the entire bottom protection plate, which is disadvantageous to the design of a thin, lightweight, and low-cost bottom protection plate.

[0031] Illustratively, the thickness of the upper skin 10 may be 1.2 millimeters, 1.8 millimeters, 2 millimeters, 2.4 millimeters, 3 millimeters, or any value therebetween, and the thickness of the lower skin 20 may be 0.4 millimeters, 0.6 millimeters, 1 millimeter, 1.5 millimeters, or any value therebetween.

[0032] In some embodiments, the intermediate layer 30 is a steel plate, and the thickness of the intermediate layer 30 is between 0.8 millimeters and 1.2 millimeters.

[0033] By using a steel plate as the intermediate layer 30, the steel plate can transmit the force of the lower skin 20 in its own XY directions and withstand deformation in the Z direction to a certain extent, thereby providing a protective effect to the battery cells.

[0034] For example, the thickness of the intermediate layer 30 may be 0.8 mm, 1 mm, 1.2 mm, or any value therebetween. If the thickness of the intermediate layer 30 is less than 0.8 mm, the steel plate's resistance to deformation in the Z direction may not meet the usage requirements, which may result in a certain safety risk for the battery pack. If the thickness of the intermediate layer 30 is greater than 1.2 mm, the steel plate will be relatively heavy, resulting in an increase in the overall weight, cost, and thickness of the bottom protection plate, which is disadvantageous to the design of a thin, lightweight, and low-cost bottom protection plate.

[0035] For example, the intermediate layer 30 may be a DP780 steel plate, a DP980 steel plate, a DP1180 steel plate, a DP1310 steel plate, a DP1470 steel plate, an HC1200 / 1500MS steel plate, or an HC1350 / 1700MS steel plate. This allows the intermediate layer 30 to have a tensile strength of 800 MPa to 1700 MPa (megapascals) and a yield strength of 800 MPa to 1500 MPa, and has advantages such as low toughness, high wear resistance, and high rigidity. This allows the intermediate layer 30 to have excellent resistance to puncture and deformation in the Z direction.

[0036] As can be seen, when the lower skin 20 is subjected to an impact force, the mesh fiber structure of the lower skin 20 disperses the force in the X and Y directions, and the intermediate layer 30 located in the middle has a larger impact-bearing area. The high strength and low toughness of the steel plate itself allow the force to be quickly dispersed in the X and Y directions of the steel plate, causing deformation over a wider area of ​​the steel plate, thereby reducing the amount of deformation of the steel plate in the Z direction. When the force is transmitted from the steel plate to the upper skin 10, the thicker mesh fiber structure of the upper skin 10 pulls the steel plate in and can withstand the Z direction deformation of the entire bottom protection plate. This reduces the Z direction deformation of the entire bottom protection plate and protects the internal structure of the battery pack. Furthermore, by making the thickness of the upper skin 10 greater than that of the lower skin 20, the steel plate can be positioned lower, allowing the steel plate to quickly respond to deformation caused by external impact forces and ensure resistance to deformation in the Z direction.

[0037] In some embodiments, there is an adhesive layer between the intermediate layer 30 and the upper skin 10 and / or there is an adhesive layer between the intermediate layer 30 and the lower skin 20 .

[0038] Based on the fact that the intermediate layer 30 is a steel plate and the upper skin 10 and lower skin 20 are composite material layers of continuous fiber reinforced resin, and taking advantage of the characteristics of polymer materials, which are highly polar and easy to adhere, a highly reliable connection can be formed between the upper skin 10, intermediate layer 30 and lower skin 20 by the adhesive method, thereby ensuring the structural stability of the bottom protection plate.

[0039] For example, when the upper skin 10, the intermediate layer 30, and the lower skin 20 are bonded together, an adhesive may be applied between the upper skin 10 and the intermediate layer 30, and another adhesive may be applied between the lower skin 20 and the intermediate layer 30. Then, by heat and pressure processing, the adhesive area between the upper skin 10, the intermediate layer 30, and the lower skin 20 is increased, and after bonding, the adhesive is cured to form an adhesive layer.

[0040] For example, when the upper skin 10, the intermediate layer 30, and the lower skin 20 are bonded together, a solid film may be placed between the upper skin 10 and the intermediate layer 30, or between the lower skin 20 and the intermediate layer 30. Thereafter, in order to bond the upper skin 10, the intermediate layer 30, and the lower skin 20 together, the solid film is softened by heat and pressure processing, and after bonding, is re-hardened to form an adhesive layer.

[0041] By connecting the upper skin 10 and the lower skin 20 to both the upper and lower sides of the intermediate layer 30 by adhesive and hot pressing, the bottom protection plate does not require surface treatment after molding, thereby ensuring that the bottom protection plate has excellent strength and rigidity, as well as the advantages of light weight and low cost.

[0042] As shown in Figures 1 and 2, in some embodiments, a buffer portion 40 is provided on the side of the upper skin 10 away from the intermediate layer 30. The buffer portion 40 supports the battery cells and can provide a certain amount of buffering effect during the battery pack assembly process and after the battery pack is installed in the vehicle. For example, during the battery pack assembly process, the buffer portion 40 supports the tray, facilitating the welding and fixing of the tray, and can also provide a buffering effect during the tray welding process. When the vehicle travels on an uneven road surface, the buffer portion 40 provides a buffering effect, thereby preventing damage to the battery cells.

[0043] Here, as long as the buffer effect of the buffer section 40 is ensured, the buffer section 40 may be set to a shape such as a cylindrical body, a rectangular parallelepiped, a prism, or an elliptical cylinder.

[0044] The buffer portion 40 may be adhered to the upper skin 10 by an adhesive method.

[0045] In some embodiments, the number of buffer portions 40 is set to be plural, and the plural buffer portions 40 are arranged at intervals on the upper skin 10. The plural buffer portions 40 may be arranged in an array or randomly on the upper surface of the upper skin 10. For example, the total number of buffer portions 40 is set to 24, and the 24 buffer portions 40 are uniformly arranged on the upper surface of the upper skin 10 in a 4*6 pattern. For example, the total number of buffer portions 40 is set to 18, and the 18 buffer portions 40 are randomly arranged on the upper surface of the upper skin 10.

[0046] In some embodiments, buffer portion 40 includes one or more of a silicone rubber buffer portion, a polyurethane buffer portion, an ethylene-vinyl acetate buffer portion, a polypropylene buffer portion, and an ethylene propylene diene rubber buffer portion, wherein the thickness of buffer portion 40 is between 5 millimeters and 20 millimeters.

[0047] When a plurality of buffer portions 40 are provided, the buffer portions 40 may be made of the same or different materials. By selecting silicone rubber, polyurethane, ethylene-vinyl acetate, polypropylene, and ethylene propylene diene rubber for the buffer portions 40, the buffer portions 40 can provide good shock absorption and buffering effects, thereby ensuring the safety of the battery pack.

[0048] For example, the thickness of the buffer portion 40 may be 5 mm, 10 mm, 15 mm, or 20 mm, or any value therebetween. If the thickness of the buffer portion 40 is less than 5 mm, the impact absorption and buffering effect of the buffer portion 40 may be reduced, and as a result, the battery cells may not be protected. If the thickness of the buffer portion 40 is greater than 20 mm, the space occupied by the buffer portion 40 in the thickness direction may increase, resulting in an increase in the overall thickness of the battery pack structure, which is disadvantageous for designing a thin and lightweight battery pack.

[0049] This eliminates the need for molds in the manufacturing process, saving mold costs and simplifying the process, reducing process costs. This reduces the weight of the bottom protection plate, which is in line with the concept of lightweight vehicle design and is beneficial for increasing the range of the finished vehicle. The multi-layer structure design of the bottom protection plate gives it excellent impact resistance, disperses external forces in the X and Y directions, and reduces deformation in the Z direction, providing effective protection for the battery pack.

[0050] Meanwhile, an embodiment of the present application further provides a battery box, which includes a bottom protective plate.

[0051] In the present embodiment, the bottom protection plate has a multi-layer structure including the upper skin 10, the intermediate layer 30, and the lower skin 20, thereby improving the strength of the bottom protection plate and enhancing its impact resistance and deformation resistance. By making the thickness of the upper skin 10 greater than that of the lower skin 20, the upper skin 10 can better withstand deformation in the thickness direction, ensuring that the bottom protection plate meets the usage requirements, while reducing the amount of material used in the lower skin 20, making the entire bottom protection plate thinner and lighter. This reduces manufacturing costs while ensuring that the overall strength of the bottom protection plate meets the standard. [Explanation of symbols]

[0052] 10: Upper skin 20: Lower skin 30: Middle class 40: Buffer section

Claims

1. The upper skin and a lower skin spaced apart from the upper skin; an intermediate layer disposed so as to be sandwiched between the upper skin and the lower skin, wherein the thickness of the upper skin is greater than the thickness of the lower skin; Bottom protection plate.

2. the thickness of the upper skin is two to three times the thickness of the lower skin, and / or the thickness of the upper skin is 1.2 to 3 millimeters; The bottom protector of claim 1 .

3. The upper skin and the lower skin are both resin layers, and a mesh fiber structure is embedded in the resin layer. The bottom protector of claim 1 .

4. The resin layer comprises one or more of a polyvinyl chloride layer, a polypropylene layer, a polyurethane layer, a polyamide layer, a polycarbonate layer, a polyethylene plastic layer, and a polyphenylene ether layer; and / or the mesh fiber structure comprises one or more of a glass fiber layer, a continuous aramid fiber layer, a basalt fiber layer, and a carbon fiber layer. The bottom protector of claim 3 .

5. When a plurality of types of resin layers are provided, the plurality of types of resin layers are provided so as to be stacked, and / or when a plurality of types of mesh fiber structures are provided, the plurality of types of mesh fiber structures are provided so as to be stacked. The bottom protector of claim 4.

6. The intermediate layer is a steel plate, and the thickness of the intermediate layer is 0.8 mm to 1.2 mm. The bottom protector of claim 1 .

7. There is an adhesive layer between the intermediate layer and the upper skin, and / or there is an adhesive layer between the intermediate layer and the lower skin. The bottom protector of claim 6.

8. a buffer portion is provided on the side of the upper skin away from the intermediate layer, wherein the number of the buffer portions is set to be plural, and the plural buffer portions are arranged at intervals on the upper skin; The bottom protector of claim 1 .

9. the buffer portion includes at least one of a silicone rubber buffer portion, a polyurethane buffer portion, an ethylene-vinyl acetate buffer portion, a polypropylene buffer portion, and an ethylene propylene diene rubber buffer portion; The bottom protector of claim 8.

10. The thickness of the buffer portion is 5 mm to 20 mm. The bottom protector of claim 8.

11. A bottom protection plate according to any one of claims 1 to 10, battery box.

Images