Bottom protective plate, battery pack and electrical equipment

Abstract

To provide a bottom protective plate that improves the protective effect of battery cells. [Solution] A bottom protective plate, a battery pack, and an electrical device are provided, the bottom protective plate comprising a protective outer layer 10, an impact-resistant layer 20, and an energy-absorbing layer 30. The protective outer layer comprises a first fiber-reinforced composite layer 11 and a second fiber-reinforced composite layer 12 spaced apart, the impact-resistant layer is provided between the first fiber-reinforced composite layer and the second fiber-reinforced composite layer, and the energy-absorbing layer is provided sandwiched between the first fiber-reinforced composite layer and the impact-resistant layer.

Description

Technical Field

[0001] This application claims the priority of a Chinese patent application with application number 202422199581.8 filed with the Chinese Patent Office on September 6, 2024, the priority of a Chinese patent application with application number 202422211865.4 filed with the Chinese Patent Office on September 9, 2024, and the priority based on an international application with application number PCT / CN2024 / 136952 filed on December 5, 2024, and incorporates by reference all the contents described in those applications.

[0002] This application relates to the field of battery technology, specifically to a bottom protection plate, a battery pack, and an electrical device.

Background Art

[0003] In related technologies, a bottom protection plate is provided at the bottom of a battery pack. The bottom protection plate is configured to protect the battery cells inside the battery pack and prevent safety accidents caused by damage to the battery pack when the bottom of the battery pack is subjected to the impact of foreign objects.

Summary of the Invention

Problems to be Solved by the Invention

[0004] Conventional bottom protection plates have relatively weak impact resistance, and the impact force is easily transmitted to the battery cells inside the battery pack through the bottom protection plate, resulting in damage to the battery cells.

Means for Solving the Problems

[0005] In a first aspect, an embodiment of this application provides a bottom protection plate, which includes a protection outer layer, an impact-resistant layer, and an energy absorption layer. The protection outer layer includes a first fiber-reinforced composite layer and a second fiber-reinforced composite layer provided at intervals. The impact-resistant layer is provided between the first fiber-reinforced composite layer and the second fiber-reinforced composite layer, and the energy absorption layer is provided so as to be sandwiched between the first fiber-reinforced composite layer and the impact-resistant layer.

[0006] In a second embodiment, the embodiment of the present application provides a battery pack, the battery pack including the bottom protective plate described above.

[0007] In a third aspect, an embodiment of the present application provides an electrical device, the electrical device including the battery pack described above. [Effects of the Invention]

[0008] In the embodiments of the present invention, the bottom protective plate includes a protective outer layer, an impact-resistant layer, and an energy-absorbing layer. The protective outer layer includes a first fiber-reinforced composite layer and a second fiber-reinforced composite layer, and the impact-resistant layer and the energy-absorbing layer are provided between the first fiber-reinforced composite layer and the second fiber-reinforced composite layer. This not only provides the bottom protective plate with insulating, abrasion-resistant, and puncture-resistant properties, but also protects the impact-resistant layer and the energy-absorbing layer, preventing them from corroding. The impact-resistant layer can withstand external impact forces and disperse impact forces concentrated at one location to different locations, preventing foreign objects from directly piercing the bottom protective plate. The energy-absorbing layer absorbs the impact energy of the impact-resistant layer, preventing the impact-resistant layer from undergoing significant deformation or being punctured, and also preventing the impact force from being transmitted to the battery cells in the battery pack, thereby improving the protective effect on the battery cells.

[0009] The battery pack provided in this application has all the effects of the invention relating to the bottom protective plate described above, and a detailed explanation is omitted here.

[0010] The electrical equipment provided in this application has all the effects of the above-described inventions relating to battery packs, and such explanations are omitted here. [Brief explanation of the drawing]

[0011] [Figure 1] This is a schematic perspective view relating to the bottom protective plate provided in the embodiment of the present application. [Figure 2] This is an exploded view showing the structure of the bottom protective plate provided in the embodiment of the present application. [Figure 3]This is a cross-sectional view showing the structure of the bottom protective plate provided in the embodiment of the present application. [Figure 4] This is a schematic diagram showing the structure of the energy absorption layer in the bottom protective plate provided in the embodiment of the present application. [Figure 5] This is a cross-sectional view showing the structure of the battery pack provided in the embodiment of the present application. [Modes for carrying out the invention]

[0012] To address the problem of external impact forces being easily transmitted to the battery cells in the battery pack via the bottom protective plate, according to a first aspect of the present invention, a bottom protective plate 100 is provided as shown in Figures 1 to 3, the bottom protective plate 100 includes a protective outer layer 10, an impact-resistant layer 20, and an energy-absorbing layer 30. Here, the protective outer layer 10 includes a first fiber-reinforced composite layer 11 and a second fiber-reinforced composite layer 12, the impact-resistant layer 20 is provided between the first fiber-reinforced composite layer 11 and the second fiber-reinforced composite layer 12, and the energy-absorbing layer 30 is provided sandwiched between the first fiber-reinforced composite layer 11 and the impact-resistant layer 20.

[0013] Specifically, in this embodiment, the protective outer layer 10 is composed of a first fiber-reinforced composite layer 11 and a second fiber-reinforced composite layer 12. The first fiber-reinforced composite layer 11 and the second fiber-reinforced composite layer 12 form the surface structure of the bottom protective plate 100. Both the first fiber-reinforced composite layer 11 and the second fiber-reinforced composite layer 12 are composite materials formed by a molding process such as winding, compression molding, or extrusion molding of a reinforcing fiber material and a matrix material. The reinforcing fibers may be glass fibers, carbon fibers, aramid fibers, etc., and the matrix material may be resin, metal, ceramic, etc. The reinforcing fibers and matrix materials used in the first fiber-reinforced composite layer 11 and the second fiber-reinforced composite layer 12 may be the same or different, and the specific configuration may be flexibly set as needed.

[0014] Furthermore, fiber-reinforced composite materials possess properties such as high strength, lightweight, and corrosion resistance. When the reinforcing fibers in a fiber-reinforced composite material are glass fibers or aramid fibers and the matrix material is resin, the fiber-reinforced composite material exhibits even better insulation properties. Therefore, by making the first fiber-reinforced composite layer 11 and the second fiber-reinforced composite layer 12 the surface structure of the bottom protective plate 100, the bottom protective plate 100 not only has insulation, abrasion resistance, and puncture resistance, but also protects the impact-resistant layer 20 and the energy-absorbing layer 30, preventing corrosion of the impact-resistant layer 20 and the energy-absorbing layer 30. Consequently, there is no need to apply an insulating coating to the surface of the bottom protective plate 100, and manufacturing costs can be reduced.

[0015] As shown in Figure 5, by attaching the bottom protective plate 100 to the casing 210 of the battery pack 200, the first fiber-reinforced composite layer 11 can be brought closer to the battery cells 220 than the second fiber-reinforced composite layer 12, meaning that the battery cells 220 can be placed directly on the first fiber-reinforced composite layer 11.

[0016] As shown in Figure 2 or Figure 3, the bottom protective plate 100 of the present invention further includes an impact-resistant layer 20, which has a certain degree of strength and toughness to withstand external impact forces, and its specific material may be a metal plate with a certain degree of strength, such as a steel plate or an alloy plate (for example, a titanium alloy or a magnesium-aluminum alloy). If there is a protruding stone on the road surface on which the automobile is traveling, the stone may rub against the bottom of the battery pack 200, and at that time the bottom protective plate 100 will be subjected to an impact force from the stone, but because the impact-resistant layer 20 has a certain degree of strength, it can prevent the bottom protective plate 100 from being pierced when subjected to an external impact force. In addition, because the impact-resistant layer 20 has a certain degree of toughness, when the impact-resistant layer 20 is subjected to an external impact force, the impact-resistant layer 20 will undergo a certain degree of deformation, and thereby the impact force can be distributed to different locations.

[0017] Exemplary, in one embodiment, the impact-resistant layer 20 is a steel plate, and to improve impact resistance, the impact-resistant layer 20 may be made of super-strong steel (for example, steel of type DP1470).

[0018] As shown in Figure 2 or Figure 3, the bottom protective plate 100 of the present invention further includes an energy absorption layer 30, which absorbs the impact energy of the impact-resistant layer 20, preventing external impact forces from being directly transmitted to the battery cells 220 in the battery pack 200, thereby improving the protective effect on the battery cells 220.

[0019] In this embodiment, the energy absorption layer 30 may be made from one or more of the following materials: balsa wood, high-density polyurethane foam, porous metal energy-absorbing material (aluminum honeycomb, foamed aluminum, etc.), and polymer material (EVA foam material, etc.). In short, the energy absorption layer 30 may be made from a material that has a certain degree of deformability, and when an impact force is transmitted to the energy absorption layer 30, the energy absorption layer 30 absorbs the impact energy by deforming itself, thereby preventing the impact force from being transmitted to the battery cells 220 in the battery pack 200.

[0020] As shown in Figures 3 and 5, in this embodiment, the energy absorption layer 30 is located between the first fiber-reinforced composite layer 11 and the impact-resistant layer 20. That is, the energy absorption layer 30 is closer to the battery cell 220 than the impact-resistant layer 20, which makes it possible to more effectively prevent the impact force of the impact-resistant layer 20 from being transmitted to the battery cell 220.

[0021] As can be understood from above, in the embodiments of the present application, the bottom protection plate 100 includes a protection outer layer, a shock-resistant layer 20, and an energy absorption layer 30. The protection outer layer includes a first fiber reinforced composite layer 11 and a second fiber reinforced composite layer 12. By providing the shock-resistant layer 20 and the energy absorption layer 30 between the first fiber reinforced composite layer 11 and the second fiber reinforced composite layer 12, the bottom protection plate 100 not only has insulation, wear resistance, and puncture resistance, but also protects the shock-resistant layer 20 and the energy absorption layer 30, and can prevent the shock-resistant layer 20 and the energy absorption layer 30 from being corroded. The shock-resistant layer 20 can withstand an external impact force, disperse the impact force concentrated at a certain position to different positions, and prevent foreign objects from directly breaking through the bottom protection plate 100. By absorbing the impact energy of the shock-resistant layer 20, the energy absorption layer 30 can not only prevent the shock-resistant layer 20 from undergoing large deformation or being broken through, but also prevent the impact force from being transmitted to the battery cells 220 in the battery pack 200, and can improve the protection effect on the battery cells 220.

[0022] Exemplarily, in one embodiment, the energy absorption layer 30 is made of balsa wood. Specifically, balsa wood is one of the lightest woods in the world, with a weight of only 0.1 gram per cubic centimeter. The lightweight property of balsa wood makes it easy to deform when receiving an impact, which contributes to the ability to absorb and disperse impact energy. In addition, the microstructure of balsa wood has porosity, and these gaps and channels function as "buffer regions" for energy absorption and dispersion when receiving an impact, slow down the transmission speed of the shock wave, and can reduce the destructive effect of the impact energy on the material. Balsa wood undergoes elastic deformation or plastic deformation when receiving an impact, and these deformation processes themselves absorb a large amount of impact energy. Although balsa wood is lightweight, its structure is robust and not easily completely broken under impact, so it can absorb energy while maintaining a certain degree of structural integrity.

[0023] Therefore, in this embodiment, by manufacturing the energy absorption layer 30 with balsa wood, not only can the impact energy of the impact-resistant layer 20 be more effectively absorbed, but also the structure of the bottom protection plate 100 can be made more robust and less likely to be damaged.

[0024] Exemplarily, in one embodiment, the protective outer layer 10, the impact-resistant layer 20, and the energy absorption layer 30 are combined by the Resin Transfer Molding (RTM) method to form the bottom protection plate 100. Specifically, in this embodiment, the impact-resistant layer 20 is manufactured with a steel plate, the energy absorption layer 30 is manufactured with balsa wood, and the protective outer layer 10, the impact-resistant layer 20, and the energy absorption layer 30 are combined by the Resin Transfer Molding method to form the bottom protection plate 100.

[0025] Here, the Resin Transfer Molding method is an advanced composite material forming technology, and its basic principle is to inject resin into a closed mold and infiltrate and cure the reinforcing material. Specifically, during molding, first, the protective outer layer 10, the impact-resistant layer 20, and the energy absorption layer 30 are laid in the cavity of the mold, and then, by a resin injection machine, the resin adhesive is injected into the cavity with a certain pressure. The resin fully penetrates between the fiber reinforcing material and each layer (that is, the protective outer layer 10, the impact-resistant layer 20, and the energy absorption layer 30) under the action of pressure, is cured under specific conditions, and finally is demolded to obtain a composite material product, that is, the bottom protection plate 100.

[0026] As can be understood, by the Resin Transfer Molding method, the resin can be fully infiltrated between the first fiber reinforced composite layer 11 and the energy absorption layer 30, between the energy absorption layer 30 and the impact-resistant layer 20, and between the impact-resistant layer 20 and the second fiber reinforced composite layer 12, and thus each layer in the bottom protection plate 100 can be firmly bonded to each other, improving the structural strength and structural stability of the bottom protection plate 100.

[0027] In addition, in order to improve the composite effect of each layer in the bottom protection plate 100, it may be manufactured using the high-pressure resin injection molding method (the injection pressure of the adhesive is usually 1.0 - 6.0 MPa or more).

[0028] Exemplary, in one embodiment, as shown in Figures 2 and 3, a drain groove 31 is recessed in the surface of the energy absorption layer 30 facing the impact-resistant layer 20, and the drain groove 31 penetrates to the outer circumferential surface of the energy absorption layer 30, and the drain groove 31 is configured to allow resin to flow between the energy absorption layer 30 and the impact-resistant layer 20.

[0029] Specifically, in this embodiment, as described above, the protective outer layer 10, the impact-resistant layer 20, and the energy-absorbing layer 30 are combined by a resin injection molding method to form the bottom protective plate 100. The energy-absorbing layer 30 is made of balsa wood so that the resin can flow more sufficiently between the energy-absorbing layer 30 and the impact-resistant layer 20. A drain groove 31 is recessed in the surface of the energy-absorbing layer 30 facing the impact-resistant layer 20, and the drain groove 31 penetrates to the outer surface of the energy-absorbing layer 30. As a result, the resin flows between the energy-absorbing layer 30 and the impact-resistant layer 20 via the drain groove 31, that is, the resin flows more sufficiently between the energy-absorbing layer 30 and the impact-resistant layer 20, thereby improving the combined effect of the energy-absorbing layer 30 and the impact-resistant layer 20.

[0030] Exemplary, in one embodiment, as shown in Figure 2 or Figure 4, multiple drain grooves 31 are provided, and the multiple drain grooves 31 intersect and communicate with each other. As can be understood, by providing multiple drain grooves 31, more resin can be introduced between the energy absorption layer 30 and the impact-resistant layer 20, thereby improving the combined effect between the energy absorption layer 30 and the impact-resistant layer 20. Furthermore, by having the multiple drain grooves 31 intersect and communicate with each other, the efficiency of resin filling the drain grooves 31 is improved, preventing a situation where part of the drain grooves 31 are not yet filled with resin after molding. In addition, after the resin has cured, a "resin grid structure" is formed between the energy absorption layer 30 and the impact-resistant layer 20, thereby improving the combined effect between the energy absorption layer 30 and the impact-resistant layer 20.

[0031] The extension direction of the multiple drain grooves 31 may be flexibly designed as needed. For example, in one embodiment, as shown in Figure 4, the energy absorption layer 30 is a rectangular plate with a length direction and a width direction, and the drain grooves 31 include a plurality of first drain grooves 311 and a plurality of second drain grooves 312. The first drain grooves 311 extend along the length direction of the energy absorption layer 30, and the plurality of first drain grooves 311 are spaced apart along the width direction of the energy absorption layer 30. The second drain grooves 312 extend along the width direction of the energy absorption layer 30, and the plurality of second drain grooves 312 are spaced apart along the length direction of the energy absorption layer 30.

[0032] In other words, in this embodiment, multiple first drain grooves 311 and multiple second drain grooves 312 intersect vertically and horizontally, and any one of the first drain grooves 311 and any one of the second drain grooves 312 intersect perpendicularly. This simplifies the arrangement of the multiple drain grooves 31, making machining easier and allowing for more appropriate control of the spacing between the drain grooves 31.

[0033] Furthermore, in one embodiment, as shown in Figure 4, a plurality of first drain grooves 311 are arranged at uniform intervals along the width direction of the energy absorption layer 30, and / or a plurality of second drain grooves 312 are arranged at uniform intervals along the length direction of the energy absorption layer 30, thereby distributing the resin more uniformly between the energy absorption layer 30 and the impact-resistant layer 20, and consequently ensuring that the composite strength at each position of the energy absorption layer 30 and the impact-resistant layer 20 is more uniform, and that the energy absorption effect at each position of the energy absorption layer 30 is more uniform.

[0034] As an example, in one embodiment, the cross-section of the drain groove 31 is an open polygon with one side open. Specifically, in this embodiment, the drain groove 31 is provided with a plurality of side walls, which are sequentially connected at their ends, and the first and last side walls in the connection order are not connected, so that the cross-section of the drain groove 31 has an open polygonal structure with one side open.

[0035] Here, the number of side walls of the drain groove 31 may be flexibly set as needed. For example, in one embodiment, as shown in Figure 3, the drain groove 31 is provided with two side walls arranged at an angle, and as a result the cross-section of the drain groove 31 becomes V-shaped, which simplifies the structure of the drain groove 31 and makes processing easier.

[0036] Alternatively, for example, in some other embodiments, the number of side walls of the drain groove 31 may be set to three. Of these, two side walls are arranged parallel to each other and spaced apart, and one side wall is connected perpendicularly between the two parallel side walls. In this case, the cross-section of the drain groove 31 is a rectangular structure with one side open.

[0037] In short, the number of side walls of the drain groove 31 and the size of the angle between the side walls may be flexibly set as needed.

[0038] Alternatively, in another embodiment, the cross-section of the drain groove 31 may be an arc shape with a radian smaller than 360°. Specifically, the inner wall of the drain groove 31 extends in an arc shape and has a radian smaller than 360°. In this case, the cross-section of the drain groove 31 is an arc shape with a radian smaller than 360°, which ensures that the drain groove 31 has an opening and facilitates adhesion of the resin in the drain groove 31 to the impact-resistant layer 20.

[0039] Here, the cross-section of the drain groove 31 may be a semicircular shape, a semielliptical shape, an arc shape with a radian of 90°, or the like.

[0040] Of course, in some other embodiments, the cross-section of the drain groove 31 may have a different shape (e.g., an irregular shape). The specific shape may be flexibly designed as needed.

[0041] For example, in one embodiment, the thickness of the energy absorption layer 30 is 5 mm or more and 10 mm or less, and the specific thickness may be 5 mm, 5.5 mm, 6 mm, 6.5 mm, 7 mm, 7.5 mm, 8 mm, 8.5 mm, 9 mm, 9.5 mm, 10 mm, etc.

[0042] As can be understood, if the thickness of the energy absorption layer 30 is less than 5 millimeters, the energy absorption effect of the energy absorption layer 30 may be insufficient. On the other hand, if the thickness of the energy absorption layer 30 is greater than 10 millimeters, the thickness of the bottom protective plate 100 may be excessive. Therefore, in this embodiment, by setting the thickness of the energy absorption layer 30 to be between 5 millimeters and 10 millimeters, it is possible to ensure that the energy absorption layer 30 has good buffer and energy absorption effect, and to prevent the bottom protective plate 100 from becoming excessively thick.

[0043] Referring to Figure 3, the thickness direction of the energy absorption layer 30 is the same as the lamination direction of the first fiber-reinforced composite layer 11, the energy absorption layer 30, the impact-resistant layer 20, and the second fiber-reinforced composite layer 12.

[0044] For example, in one embodiment, the impact-resistant layer 20 is made of a metal material and has a yield strength of 1200 megapascals or more. Specifically, in this embodiment, the impact-resistant layer 20 is made of DP1470 ultra-high-strength steel and has a yield strength of 1200 megapascals or more, thereby improving the impact resistance of the impact-resistant layer 20 and consequently providing a better protective effect.

[0045] For example, in one embodiment, the thickness of the impact-resistant layer 20 is 1 millimeter or more and 2 millimeters or less, and the specific thickness may be 1 millimeter, 1.1 millimeters, 1.2 millimeters, 1.3 millimeters, 1.4 millimeters, 1.5 millimeters, 1.6 millimeters, 1.7 millimeters, 1.8 millimeters, 1.9 millimeters, 2 millimeters, etc.

[0046] As can be understood, if the thickness of the impact-resistant layer 20 is less than 1 millimeter, the impact resistance of the impact-resistant layer 20 will be relatively weak, while if the thickness of the impact-resistant layer 20 is greater than 2 millimeters, the weight and cost of the bottom protective plate 100 may increase. Therefore, in this embodiment, by setting the thickness of the impact-resistant layer 20 to be between 1 millimeter and 2 millimeters, it is possible to ensure that the impact-resistant layer 20 has good impact resistance while preventing the weight and cost of the bottom protective plate 100 from becoming excessive.

[0047] For example, in one embodiment, the thickness of the first fiber-reinforced composite layer 11 and the second fiber-reinforced composite layer 12 are both 0.6 mm or more and 2 mm or less, and the specific thicknesses may be 0.6 mm, 0.7 mm, 0.8 mm, 0.9 mm, 1 mm, 1.1 mm, 1.2 mm, 1.3 mm, 1.4 mm, 1.5 mm, 1.6 mm, 1.7 mm, 1.8 mm, 1.9 mm, 2 mm, etc.

[0048] To understand this, if the thickness of both the first fiber-reinforced composite layer 11 and the second fiber-reinforced composite layer 12 is less than 0.6 millimeters, the corrosion resistance and puncture resistance of the protective outer layer 10 may be insufficient. On the other hand, if the thickness of both the first fiber-reinforced composite layer 11 and the second fiber-reinforced composite layer 12 is greater than 2 millimeters, manufacturing may become difficult. Therefore, in this embodiment, by setting the thickness of both the first fiber-reinforced composite layer 11 and the second fiber-reinforced composite layer 12 to be 0.6 millimeters or more and 2 millimeters or less, it is possible to ensure that the protective outer layer 10 has good corrosion resistance and puncture resistance, while also facilitating the manufacturing of the first fiber-reinforced composite layer 11 and the second fiber-reinforced composite layer 12.

[0049] As shown in Figure 5, the embodiment of the present application further provides a battery pack 200 which includes a bottom protective plate 100, and the specific structure of the bottom protective plate 100 may be described by the embodiment described above. Since the battery pack 200 of the present application uses all the technical ideas of all the embodiments described above, the battery pack 200 of the present application has at least all the effects of the inventions brought about by the technical ideas of the embodiments described above, and a detailed explanation is omitted here.

[0050] In this case, as shown in Figure 5, the battery pack 200 typically includes a casing 210 and a battery module mounted inside the casing 210, the battery module includes a plurality of battery cells 220, the bottom protective plate 100 of this application may be the bottom plate structure of the casing 210 as is, and the battery cells 220 are directly attached to the bottom protective plate 100.

[0051] Alternatively, in some other embodiments, a bottom plate is provided at the bottom of the casing 210, the battery cells 220 are directly attached to the bottom plate of the casing 210, and the bottom protection plate 100 of the present invention is fixed to the bottom of the bottom plate of the casing in order to protect the bottom of the battery cells 220 together with the bottom plate of the casing 210.

[0052] Embodiments of the present application further provide an electrical device which includes the battery pack 200 described above, and since the battery pack 200 employs all the technical solutions of all the embodiments described above, the electrical device of the present application has at least all the effects of the inventions brought about by the technical solutions of the embodiments described above, and such explanations are omitted here.

[0053] Here, electrical equipment may include automobiles, ships, industrial equipment, household appliances, etc. [Explanation of Symbols]

[0054] 100: Bottom protection plate 10:Protective outer layer 11: First fiber-reinforced composite layer 12: Second fiber-reinforced composite layer 20: Impact-resistant layer 30: Energy absorption layer 31: Drain groove 311: First drain groove 312: Second drain groove 200: Battery pack 210: Box body 220: Battery cell

Claims

1. The material comprises a protective outer layer, an impact-resistant layer, and an energy-absorbing layer, wherein the protective outer layer comprises a first fiber-reinforced composite layer and a second fiber-reinforced composite layer, the impact-resistant layer is provided between the first fiber-reinforced composite layer and the second fiber-reinforced composite layer, and the energy-absorbing layer is provided so as to be sandwiched between the first fiber-reinforced composite layer and the impact-resistant layer. Bottom protection plate.

2. The energy-absorbing layer is made from one or more of the following materials: balsa wood, high-density polyurethane foam, porous metal energy-absorbing material, and polymer material. The bottom protective plate according to claim 1.

3. A drain groove is recessed in the surface of the energy absorption layer facing the impact-resistant layer, the drain groove penetrates to the outer surface of the energy absorption layer, and the drain groove is configured to allow resin to flow between the energy absorption layer and the impact-resistant layer. The bottom protective plate according to claim 1.

4. Multiple drain grooves are provided, and these drain grooves intersect and communicate with each other. The bottom protective plate according to claim 3.

5. The energy absorption layer is in the shape of a rectangular plate and has a length direction and a width direction, and the drain groove includes a plurality of first drain grooves and a plurality of second drain grooves, the first drain grooves extend along the length direction of the energy absorption layer and the plurality of first drain grooves are spaced apart from each other along the width direction of the energy absorption layer, the second drain grooves extend along the width direction of the energy absorption layer and the plurality of second drain grooves are spaced apart from each other along the length direction of the energy absorption layer. The bottom protective plate according to claim 4.

6. The plurality of first drain grooves are arranged at uniform intervals along the width direction of the energy absorption layer, and / or the plurality of second drain grooves are arranged at uniform intervals along the length direction of the energy absorption layer. The bottom protective plate according to claim 5.

7. The cross-section of the drain groove is an open polygon with one side open, or the cross-section of the drain groove is an arc with a radian less than 360°. The bottom protective plate according to claim 3.

8. The cross-section of the drain groove is V-shaped. The bottom protective plate according to claim 3.

9. The thickness of the energy absorption layer is 5 millimeters or more and 10 millimeters or less. The bottom protective plate according to claim 1.

10. The impact-resistant layer is made of a metal material, and its yield strength is 1200 megapascals or more. The bottom protective plate according to claim 1.

11. The thickness of the impact-resistant layer is 1 millimeter or more and 2 millimeters or less. The bottom protective plate according to claim 1.

12. The thickness of both the first fiber-reinforced composite layer and the second fiber-reinforced composite layer is 0.6 mm or more and 2 mm or less. The bottom protective plate according to claim 1.

13. The protective outer layer, the impact-resistant layer, and the energy-absorbing layer are combined by a resin injection molding method to form the bottom protective plate. The bottom protective plate according to claim 1.

14. Including the bottom protective plate described in any one of claims 1 to 13, Battery pack.

15. Includes the battery pack described in claim 14, Electrical equipment.

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