Battery protection base plate, composite protective structure for battery pack, and vehicle

Abstract

In order to overcome the problem of insufficient corrosion resistance of existing battery pack bottom protection plates caused by the surface PVC layer peeling off under impact, the present application provides a battery protection bottom plate comprising a protection layer, a metal plate and a fiber-reinforced resin layer. The metal plate is located between the protection layer and the fiber-reinforced resin layer, and the metal plate and the fiber-reinforced resin layer satisfy the conditions in Formula I. [0010] JPEG2025511569000015.jpg23168 Also, the present application further discloses a composite protective structure for a battery pack, including a battery protective bottom plate, and a vehicle.

Description

[Technical Field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This disclosure claims priority to and the benefit of Chinese Patent Application No. 202210612280.6, filed on May 31, 2022. The entire contents of the above-referenced application are incorporated herein by reference.

[0002] The present disclosure relates to the technical field of vehicle batteries, and in particular to a battery protective bottom plate, a composite protective structure for a battery pack, and a vehicle. [Background technology]

[0003] With the rapid development of electric vehicles, public demands for the safety of electric vehicles are also increasing. Since power battery packs are used as the power source for electric vehicles, the safety of power battery packs is obviously important. Battery packs are generally located at the bottom of the electric vehicle chassis and connected to the chassis with bolts. The bottom of the battery pack is exposed to the outside. During daily vehicle operation, the bottom of the battery pack is susceptible to collisions, leading to damage to the case and poor protection. Stones flying from the bottom can also impact the battery pack during operation. To address complex operating conditions, a protective plate is usually placed at the bottom of the battery pack to protect it. The protective plate is usually made of steel, with a PVC layer sprayed on the bottom to resist impact and corrosion. However, the overall impact resistance of existing protective plates still needs to be improved. Specifically, under the impact of an external hard object, the PVC layer on the bottom surface of the protective plate is susceptible to chalking, and therefore falls off from the surface of the protective plate, exposing the inner steel plate and affecting the corrosion resistance of the protective plate. Summary of the Invention [Problem to be solved by the invention]

[0004] In response to the problem that the PVC layer on the surface of the existing battery pack bottom protection plate falls off when subjected to impact, leading to insufficient corrosion resistance, the present disclosure provides a battery protection bottom plate, a composite protection structure for a battery pack, and a vehicle. [Means for solving the problem]

[0005] The technical solutions adopted by the present disclosure to solve the above technical problems are as follows:

[0006] In a first aspect, the present disclosure provides a battery protective bottom plate comprising a protective layer, a metal plate, and a fiber-reinforced resin layer, wherein the metal plate is located between the protective plate and the fiber-reinforced resin layer, and the metal plate and the fiber-reinforced resin layer satisfy the following conditions:

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[0007] In some implementations, the metal plate and the fiber-reinforced resin layer satisfy the following conditions:

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[0008] In some implementations, the thickness d1 of the fiber reinforced resin layer is 0.6 mm to 2.0 mm.

[0009] In some implementations, the thickness d2 of the metal plate is between 0.7 mm and 1.6 mm.

[0010] In some implementations, the breaking elongation ε2 of the metal plate is between 5% and 20%.

[0011] In some implementations, the tensile strength σ2 of the metal plate is between 590 MPa and 1180 MPa.

[0012] In some implementations, the elongation at break ε 0 of the fiber reinforced resin layer is 2.5% to 8%.

[0013] In some implementations, the tensile strength σ0 of the fiber reinforced resin layer is 240 MPa to 380 MPa.

[0014] In some implementations, the material of the protective layer is selected from a fiber reinforced resin material, a resin coating, or an electrophoretic coating.

[0015] In some implementations, the thickness of the protective layer is between 0.4 mm and 1.6 mm.

[0016] In some implementations, the battery protective bottom plate further includes a fiber-reinforced resin frame, the metal plate and the fiber-reinforced resin frame being positioned between the protective layer and the fiber-reinforced resin layer, the metal plate being positioned inside the fiber-reinforced resin frame, and the top surface of the fiber-reinforced resin frame being integrally connected to the protective layer, and the bottom surface of the fiber-reinforced resin frame being integrally connected to the fiber-reinforced resin layer.

[0017] In some implementations, a plurality of mounting holes are spaced apart inside the edge of the battery protective bottom plate, and the mounting holes extend sequentially through the protective layer, the fiber reinforced resin frame, and the fiber reinforced resin layer.

[0018] In some implementations, the protective layer, the fiber-reinforced resin frame, and the fiber-reinforced resin layer are each independently selected from a glass fiber reinforced polyamide resin member, a glass fiber reinforced polypropylene resin member, a glass fiber reinforced polyethylene resin member, a glass fiber reinforced polycarbonate resin member, or a glass fiber reinforced polystyrene resin member.

[0019] In some implementations, the protective layer, the fiber-reinforced resin frame, and the fiber-reinforced resin layer are each glass fiber-reinforced resin members, and the glass fiber-reinforced resin members contain 60% to 70% glass fiber, and the glass fiber has an alkali content of less than 0.8%.

[0020] In some implementations, the protective layer includes multiple layers of a first fiber reinforced prepreg laminated together.

[0021] In some implementations, the fiber reinforced resin frame includes multiple layers of a second fiber reinforced prepreg laminated together.

[0022] In some implementations, the fiber reinforced resin layer includes multiple layers of a third fiber reinforced prepreg laminated together.

[0023] In some implementations, the metal sheet is a steel sheet, and a zinc-plated layer, a zinc-plated iron alloy layer, or an electrophoretic coating protective layer is disposed on the outer surface of the steel sheet.

[0024] In another aspect, the present disclosure provides a composite protective structure for a battery pack, including a battery pack and the above-mentioned battery protection bottom plate, wherein the battery protection bottom plate is disposed under the battery pack, and a buffer area is formed between the battery pack and the battery protection bottom plate.

[0025] In some implementations, the cushioning region is filled with a cushioning layer, which is selected from a honeycomb material or a rigid foam material.

[0026] In another aspect, the present disclosure provides a vehicle including the battery protective bottom plate or composite protective structure for a battery pack described above.

[0027] In the battery protective bottom plate according to the present disclosure, a fiber-reinforced resin layer is compounded on the surface of a metal plate, and the fiber-reinforced resin layer is used as a bottom coating structure for the metal plate, thereby preventing the metal plate from direct contact with air and external moisture and protecting the metal plate from corrosion. In addition, since the fiber-reinforced resin has good mechanical strength, the rigidity and strength of the metal plate are effectively increased, and therefore the metal plate has higher impact resistance.

[0028] Furthermore, the inventors found that when a fiber-reinforced resin layer is matched with a metal plate, some matching groups can produce battery protection bottom plates with excellent impact resistance, but some matching groups result in damage to the surface of the fiber-reinforced resin layer. Through further experiments, they found that the tensile strength and breaking elongation of the selected fiber-reinforced resin layer must have a specific corresponding relationship with the tensile strength and breaking elongation of the metal plate so that the adhesion between the fiber-reinforced resin layer and the metal plate can be ensured without being damaged when the battery protection bottom plate is impacted by external energy. The following relationship is summarized for the thickness of the fiber-reinforced resin layer and the metal plate:

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[0029] When the thickness d1 of the fiber-reinforced resin layer, the thickness d2 of the metal plate, the breaking elongation ε2 of the metal plate, the breaking elongation ε0 of the fiber-reinforced resin layer, the tensile strength σ2 of the metal plate, and the tensile strength σ0 of the fiber-reinforced resin layer satisfy the above conditions, a battery protective bottom plate with excellent impact resistance and corrosion resistance can be obtained. [Brief explanation of the drawings]

[0030] [Figure 1] 1 is a schematic structural diagram of a battery protection bottom plate according to the present disclosure; [Figure 2] 3A-3C are schematic structural diagrams of different first fiber reinforced prepreg unidirectional tapes in a protective layer according to the present disclosure. [Figure 3]3A-3C are schematic structural diagrams of different first fiber fabric reinforced prepregs in protective layers according to the present disclosure. [Figure 4] 1 is a schematic structural diagram of a composite protective structure for a battery pack according to the present disclosure; [Figure 5] FIG. 5 is a schematic enlarged view of a portion A in FIG. [Figure 6] 1 is a schematic cross-sectional view of the bottom of a composite protective structure for a battery pack according to one embodiment of the present disclosure. [Figure 7] 10 is a schematic cross-sectional view of the bottom of a composite protective structure for a battery pack according to another embodiment of the present disclosure. [Figure 8] FIG. 10 is a schematic cross-sectional view of the bottom of a composite protective structure for a battery pack according to yet another embodiment of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0031] In order to make the technical problems to be solved, technical solutions and beneficial effects of the present disclosure clearer, the present disclosure will be described in more detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely used to explain the present disclosure and are not intended to limit the present disclosure.

[0032] In the description of this disclosure, it should be understood that the orientations or positions indicated by terms such as "upper," "lower," "top," "bottom," "inside," and "outside" are based on the orientations or positions shown in the accompanying drawings and do not represent or imply that the devices or elements referred to have a particular orientation or are required to be constructed and operated in a particular orientation, but are merely for the purpose of facilitating and simplifying the description of the disclosure, and therefore should not be construed as limiting the disclosure. In the description of this disclosure, unless otherwise specified, "plurality" means two or more.

[0033] As shown in Figure 1, one embodiment of the present disclosure provides a battery protective bottom plate 1, which includes a protective layer 11, a metal plate 12, and a fiber-reinforced resin layer 14. The metal plate 12 is located between the protective layer 11 and the fiber-reinforced resin layer 14, and the metal plate 12 and the fiber-reinforced resin layer 14 satisfy the following conditions:

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[0034] The fiber-reinforced resin layer 14 serves as a bottom coating structure for the metal plate 12, preventing the metal plate 12 from coming into direct contact with air and external moisture and protecting the metal plate 12 from corrosion. Furthermore, since the fiber-reinforced resin has good mechanical strength, the rigidity and strength of the metal plate 12 are effectively increased, and therefore the metal plate 12 has higher impact resistance.

[0035] Furthermore, the inventors found that when the fiber-reinforced resin layer 14 is matched with the metal plate 12, some matching groups can produce a battery protection bottom plate 1 with excellent impact resistance, but some matching groups result in damage to the surface of the fiber-reinforced resin layer 14. Through further experiments, they found that the tensile strength and breaking elongation of the selected fiber-reinforced resin layer 14 must have a specific corresponding relationship with the tensile strength and breaking elongation of the metal plate 12 so that the adhesion between the fiber-reinforced resin layer 14 and the metal plate 12 can be ensured without being damaged when the battery protection bottom plate 1 is impacted by external energy. The following relationship is summarized for the thicknesses of the fiber-reinforced resin layer 14 and the metal plate 12:

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[0036] When the thickness d1 of the fiber-reinforced resin layer 14, the thickness d2 of the metal plate 12, the breaking elongation ε2 of the metal plate 12, the breaking elongation ε0 of the fiber-reinforced resin layer 14, the tensile strength σ2 of the metal plate 12, and the tensile strength σ0 of the fiber-reinforced resin layer 14 satisfy the above conditions, a battery protective bottom plate 1 having excellent impact resistance and corrosion resistance is obtained.

[0037] In some embodiments, the metal plate 12 and the fiber-reinforced resin layer 14 satisfy the following conditions.

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[0038] Through the definition of the above relationship, the influence of the material selection of the metal plate 12 and the fiber-reinforced resin layer 14 on the impact resistance of the battery pack 3 can be synthesized, which is beneficial to preventing the fiber-reinforced resin layer 14 on the surface from falling off when subjected to external impact, ensuring the corrosion resistance of the battery protective bottom plate 1, and extending its service life.

[0039] In some embodiments, the thickness d1 of the fiber reinforced resin layer 14 is 0.6 mm to 2.0 mm.

[0040] Specifically, the thickness d1 of the fiber reinforced resin layer 14 may be 0.6 mm, 0.7 mm, 0.8 mm, 0.9 mm, 1.0 mm, 1.1 mm, 1.2 mm, 1.3 mm, 1.4 mm, 1.5 mm, 1.6 mm, 1.8 mm, or 2.0 mm.

[0041] The thickness d1 of the fiber-reinforced resin layer 14 is related to the corrosion resistance of the metal plate 12 against external air and water vapor, and affects the bonding strength with the metal plate 12 and the overall strength after being combined with the metal plate 12. When the thickness d1 of the fiber-reinforced resin layer 14 is within the above range, it can be prevented from falling off the surface of the metal plate 12 under high-energy impact, and the corrosion prevention effect and strength-enhancing effect on the metal plate 12 can be effectively maintained.

[0042] In some embodiments, the thickness d2 of the metal plate 12 is 0.7 mm to 1.6 mm.

[0043] Specifically, the thickness d2 of the metal plate 12 may be 0.7 mm, 0.8 mm, 0.9 mm, 1.0 mm, 1.1 mm, 1.2 mm, 1.3 mm, 1.4 mm, 1.5 mm, or 1.6 mm.

[0044] The thickness d2 of the metal plate 12 affects the overall mechanical strength of the battery protection bottom plate 1. When the tensile strength of the metal plate 12 is constant, its protective strength gradually increases as the thickness of the metal plate 12 increases, but the material cost also gradually increases and the minimum ground clearance of the vehicle bottom is reduced. When the thickness d2 of the metal plate 12 is within the above range, the overall mechanical strength of the battery protection bottom plate 1 can be ensured, costs can be effectively reduced, the distance from the ground can be ensured, and the vehicle weight can be easily reduced.

[0045] In some embodiments, the breaking elongation ε2 of the metal plate 12 is 5% to 20%.

[0046] Specifically, the breaking elongation ε2 of the metal plate 12 may be 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19% or 20%.

[0047] In some embodiments, the tensile strength σ2 of the metal plate 12 is 590 MPa to 1180 MPa.

[0048] Specifically, the tensile strength σ2 of the metal plate 12 may be 590 MPa, 600 MPa, 650 MPa, 700 MPa, 750 MPa, 800 MPa, 850 MPa, 900 MPa, 950 MPa, 1000 MPa, or 1180 MPa.

[0049] The tensile strength σ2 and breaking elongation ε2 of the metal plate 12 may be tested according to GB / T 228.1-2010, "Metallic Materials - Tensile Test - Part 1: Test Method at Room Temperature." As a component that plays a primary protective role in the battery protective bottom plate 1, the metal plate 12 is exposed to complex impact conditions. Its tensile strength σ2, as an indicator of the strength of the metal plate 12, affects the deformation resistance of the metal plate 12 within its elastic deformation range. A higher tensile strength σ2 allows the metal plate 12 to withstand a stronger impact without irreversible deformation. The breaking elongation ε2 also affects the fracture resistance of the metal plate 12 after deformation. A higher breaking elongation ε2 allows the metal plate 12 to withstand a stronger impact without cracking. However, generally, a higher tensile strength σ2 of the metal plate 12 indicates a lower breaking elongation ε2. When the tensile strength σ2 and the breaking elongation ε2 are within the above ranges, the effects of different parameters on the protective performance of the metal plate 12 can be effectively taken into account, and the impact strength and crack resistance of the metal plate 12 can be ensured.

[0050] In some embodiments, the breaking elongation ε0 of the fiber reinforced resin layer 14 is 2.5% to 8%.

[0051] Specifically, the breaking elongation ε0 of the fiber reinforced resin layer 14 may be 2.5%, 2.6%, 2.8%, 2.9%, 3.0%, 3.1%, 3.2%, 3.3%, 3.4%, 3.5%, 3.6%, 3.8%, 3.9%, 4%, 4.5%, 5%, 5.5%, 6%, 6.5%, 7%, 7.5%, or 8%.

[0052] In some embodiments, the tensile strength σ0 of the fiber reinforced resin layer 14 is 240 MPa to 380 MPa.

[0053] Specifically, the tensile strength σ0 of the fiber reinforced resin layer 14 may be 240 MPa, 260 MPa, 280 MPa, 290 MPa, 300 MPa, 310 MPa, 320 MPa, 330 MPa, 340 MPa, 350 MPa, 360 MPa, 370 MPa, or 380 MPa.

[0054] The breaking elongation ε0 and tensile strength σ0 of the fiber-reinforced resin layer 14 may be tested according to GB / T 1447-2005, "Fiber-reinforced Plastic Composite Materials - Measurement of Tensile Properties." Type I samples are suitable for fiber-reinforced thermoplastic plates, and samples are manufactured according to the Type I test method specified in the national testing standard. The fiber-reinforced resin layer 14 is the surface layer of the battery protective bottom plate 1 that comes into direct contact with the impact object during impact. Therefore, improving the tensile strength σ0 is beneficial for improving the deformation resistance of the fiber-reinforced resin layer 14. An increase in the tensile strength σ0 leads to a decrease in the breaking elongation ε0, which can affect the adhesion of the fiber-reinforced resin layer 14 to the metal plate 12 and potentially lead to delamination during impact. When the tensile strength σ0 and breaking elongation ε0 of the fiber-reinforced resin layer 14 are within the above ranges, the fiber-reinforced resin layer 14 can effectively withstand external impact without delamination or shedding.

[0055] In practical applications, the above six parameters are interrelated and inseparable in terms of improving the impact resistance of the battery pack 3 and preventing chalking and detachment of the fiber-reinforced resin layer. For example, if the tensile strength σ2 of the metal plate 12 is not well matched to the tensile strength σ0 of the fiber-reinforced resin layer 14, asynchronous vibrations are easily induced, increasing the likelihood of delamination. If the breaking elongation ε2 of the metal plate 12 is not well matched to the breaking elongation ε0 of the fiber-reinforced resin layer 14, the fiber-reinforced resin layer 14 is more susceptible to chalking due to impact. The tensile strength σ2 of the metal plate 12 is related to the breaking elongation ε2 of the metal plate 12, and the tensile strength σ0 of the fiber-reinforced resin layer 14 is related to the breaking elongation ε0 of the fiber-reinforced resin layer 14. When the thickness d2 of the metal plate 12 and the thickness d1 of the fiber reinforced resin layer 14 are increased, the requirements for the tensile strength σ2 of the metal plate 12 and the tensile strength σ0 of the fiber reinforced resin layer 14 can be reduced, but the total mass and thickness of the battery protection bottom plate 1 will be increased accordingly. This is not conducive to meeting the requirements for reducing the vehicle's weight and cost, and also leads to a reduction in the distance between the vehicle and the ground. This is not conducive to meeting the requirements for reducing the vehicle's weight and cost, and leads to a reduction in the minimum ground clearance. Therefore,

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[0056] In some embodiments, the material of the protective layer 11 is selected from a fiber-reinforced resin material, a resin coating, or an electrophoretic coating. The protective layer 11 is configured to improve the corrosion resistance and composite strength of the metal plate 12.

[0057] In some embodiments, the thickness of the protective layer 11 is 0.4 mm to 1.6 mm. Specifically, the thickness of the protective layer 11 may be 0.4 mm, 0.5 mm, 0.6 mm, 0.7 mm, 0.8 mm, 0.9 mm, 1.0 mm, 1.1 mm, 1.2 mm, 1.3 mm, 1.4 mm, 1.5 mm, or 1.6 mm. The thickness of the protective layer 11 mainly affects the water vapor permeation resistance and the bonding strength of the protective layer 11 to the metal plate 12. When the thickness of the protective layer 11 is within the above range, the protective performance for the metal plate 12 can be effectively improved, and the bonding strength of the protective layer 11 to the metal plate 12 can be improved.

[0058] In some embodiments, the battery protective bottom plate 1 further includes a fiber-reinforced resin frame 13. The metal plate 12 and the fiber-reinforced resin frame 13 are located between the protective layer 11 and the fiber-reinforced resin layer 14, and the metal plate 12 is located inside the fiber-reinforced resin frame 13. The top surface of the fiber-reinforced resin frame 13 is integrally connected to the protective layer 11, and the bottom surface of the fiber-reinforced resin frame 13 is integrally connected to the fiber-reinforced resin layer 14.

[0059] The fiber reinforced resin frame 13 is disposed on the outer periphery of the metal plate 12 as a frame connection transition member for the protective layer 11 and the fiber reinforced resin layer 14. This effectively cancels the influence of the thickness of the metal plate 12 on the frame connection of the protective layer 11 and the fiber reinforced resin layer 14, ensures the strength of the frame of the battery protection bottom plate 1, makes it easier to use the frame of the battery protection bottom plate 1 as an attachment structure for the battery protection bottom plate to the battery, and improves the impact resistance of the battery protection bottom plate.

[0060] As shown in Figures 4 and 5, in some embodiments, a plurality of mounting holes 15 are spaced apart inside the edge of the battery protective bottom plate 1, and the mounting holes 15 extend sequentially through the protective layer 11, the fiber-reinforced resin frame 13, and the fiber-reinforced resin layer 14.

[0061] The mounting holes 15 are configured to fasten and fix the battery protection bottom plate 1 to the bottom of the battery pack 3. The mounting holes 15 are provided on the inside edge of the battery protection bottom plate 1 and extend through the protective layer 11, the fiber-reinforced resin frame 13, and the fiber-reinforced resin layer 14 in order, thereby preventing the mounting holes 15 from extending through the metal plate 12 and avoiding corrosion problems caused by the metal plate 12 being exposed at the mounting holes 15. The fiber-reinforced resin frame 13 also helps to improve the overall thickness and tensile shear strength of the mounting position, providing sufficient mounting stability.

[0062] A plurality of mounting holes 15 are provided on the outer periphery of the metal plate 12, thereby distributing the upper gravity and bottom impact force acting on the metal plate 12 evenly.

[0063] Specifically, when mounting, connecting members are provided to pass through the mounting holes 15 and fix the battery protection bottom plate 1 to the bottom of the battery pack 3. The connecting members are rivets, screws, or bolts.

[0064] In different embodiments, the resins of protective layer 11, fiber-reinforced resin frame 13, and fiber-reinforced resin layer 14 are each independently selected from thermosetting and / or thermoplastic materials. Examples may include, but are not limited to, epoxy resins, phenolic resins, phenols, cyanate esters, imides (such as polyimides, bismaleimides (BMI), and polyetherimides), polypropylene, polyesters, benzoxazines, polybenzimidazoles, polybenzothiazoles, polyamides, polyamideimides, polysulfones, polyethersulfones, polycarbonates, polyethylene terephthalates, and polyetherketones (such as polyetherketone (PEK), polyetheretherketone (PEEK), and polyetherketoneketone (PEKK)), and combinations thereof.

[0065] In different embodiments, the fibers of the protective layer 11, the fiber-reinforced resin frame 13, and the fiber-reinforced resin layer 14 are each independently selected from glass fibers, aramid fibers, carbon fibers, graphite fibers, boron fibers, aromatic polyamide fibers, and mixtures thereof.

[0066] The fibers of the protective layer 11, the fiber-reinforced resin frame 13, and the fiber-reinforced resin layer 14 may be embedded in the resin in the form of chopped fibers, long-cut fibers, nonwoven fabric, unidirectional reinforcing fiber substrate, woven fabric, or the like.

[0067] In some embodiments, the protective layer 11, the fiber-reinforced resin frame 13, and the fiber-reinforced resin layer 14 are each independently selected from a glass fiber-reinforced polyamide resin member, a glass fiber-reinforced polypropylene resin member, a glass fiber-reinforced polyethylene resin member, a glass fiber-reinforced polycarbonate resin member, or a glass fiber-reinforced polystyrene resin member.

[0068] In some embodiments, the protective layer 11, the fiber-reinforced resin frame 13 and the fiber-reinforced resin layer 14 are made of the same resin material, which can ensure the material affinity between the different layers, thereby ensuring the degree of bonding integration between the different layers and improving the overall strength.

[0069] In some implementations, the protective layer 11, the fiber-reinforced resin frame 13, and the fiber-reinforced resin layer 14 are each glass fiber-reinforced resin members, and the glass fiber-reinforced resin members contain 60% to 70% glass fiber, which is beneficial for improving the material strength of the protective layer 11, the fiber-reinforced resin frame 13, and the fiber-reinforced resin layer 14.

[0070] In some embodiments, the alkali content of the glass fibers is less than 0.8%.

[0071] When the alkali content of the glass fiber is less than 0.8%, the aging resistance of the protective layer 11, the fiber-reinforced resin frame 13 and the fiber-reinforced resin layer 14 is improved, and the performance degradation of the materials after long-term use is slowed down.

[0072] In some embodiments, the glass fibers are selected from E-glass fibers or S-glass fibers.

[0073] In some embodiments, the protective layer 11 comprises multiple layers of a first fiber reinforced prepreg laminated together.

[0074] In some embodiments, the fiber reinforced resin frame 13 comprises multiple layers of a second fiber reinforced prepreg laminated together.

[0075] In some embodiments, the fiber reinforced resin layer 14 comprises multiple layers of a third fiber reinforced prepreg laminated together.

[0076] 2, in one embodiment, the protective layer 11 includes multiple layers of first fiber reinforced prepreg unidirectional tapes 111 laminated together. The fiber arrangement directions of two adjacent layers of the first fiber reinforced prepreg unidirectional tapes 111 are offset from each other by approximately 90°, and the allowable layer angle deviation range of two adjacent layers of the first fiber reinforced prepreg unidirectional tapes 111 is ±20°.

[0077] The fibers of each first fiber reinforced prepreg unidirectional tape 111 are arranged in one direction, and when a tensile force is applied along the fiber extension direction, the fibers of the first fiber reinforced prepreg unidirectional tape 111 can effectively bear the tensile force. The stress uniformity in each direction of the protective layer 11 is improved by shifting the fiber arrangement directions of adjacent first fiber reinforced prepreg unidirectional tapes 111 by approximately 90° from each other.

[0078] The fiber-reinforced resin frame 13 includes multiple layers of second fiber-reinforced unidirectional prepreg tapes stacked together. The fibers of each second fiber-reinforced unidirectional prepreg tape are arranged in one direction. The fiber arrangement directions of two adjacent layers of the second fiber-reinforced unidirectional prepreg tapes are offset by approximately 90° from each other, and the allowable layer angle deviation range of two adjacent layers of the second fiber-reinforced unidirectional prepreg tapes is ±20°.

[0079] The fiber-reinforced resin layer 14 includes multiple layers of third fiber-reinforced unidirectional prepreg tapes stacked together. The fibers of each third fiber-reinforced unidirectional prepreg tape are arranged in one direction. The fiber arrangement directions of two adjacent layers of the third fiber-reinforced unidirectional prepreg tapes are offset by approximately 90° from each other, and the allowable layer angle deviation range of two adjacent layers of the third fiber-reinforced unidirectional prepreg tapes is ±20°.

[0080] The fiber arrangement of the fiber reinforced resin frame 13 and the fiber reinforced resin layer 14 is similar to that of the protective layer 11, and the details will not be repeated.

[0081] As shown in FIG. 3, in another embodiment, the protective layer 11 includes multiple layers of first fiber fabric reinforced prepregs 112 stacked together, with the fibers of each first fiber fabric reinforced prepreg 112 forming a staggered weave.

[0082] The fiber reinforced resin frame 13 includes multiple layers of second fiber fabric reinforced prepreg laminated together, with the fibers of each second fiber fabric reinforced prepreg forming a staggered pattern of fabric.

[0083] The fiber reinforced resin layer 14 includes multiple layers of third fiber fabric reinforced prepreg laminated together, with the fibers of each third fiber fabric reinforced prepreg forming a staggered pattern of fabric.

[0084] In some embodiments, the metal plate 12 is selected from iron and its alloys, aluminum and its alloys, magnesium and its alloys, copper and its alloys, titanium and its alloys, or nickel and its alloys.

[0085] In one embodiment, the metal sheet 12 is a steel sheet, and a zinc-plated layer, a zinc-plated iron alloy layer, or an electrophoretic coating protective layer is disposed on the outer surface of the steel sheet.

[0086] Compared with other metal materials, the steel plate used as the metal plate 12 has better tensile strength and elongation, and can meet the requirements of impact resistance, which is beneficial for enhancing the protective effect for the battery pack 3.

[0087] The zinc-plated layer, zinc-plated iron alloy layer, or electrophoretic coating protective layer is disposed on the outer surface of the steel sheet to enhance the steel sheet's corrosion resistance. If the protective layer 11 or fiber-reinforced resin layer 14 is damaged, the galvanic effect formed between the zinc-plated layer or zinc-plated iron alloy layer and the steel sheet causes the zinc-plated layer or zinc-plated iron alloy layer to corrode before the steel sheet, thereby providing a protective effect for the steel sheet. The electrophoretic coating protective layer has good adhesion and can effectively isolate the steel sheet from the external environment.

[0088] 4 and 6 to 8, another embodiment of the present disclosure provides a composite protective structure for a battery pack, including a battery pack 3 and the above-mentioned battery protection bottom plate 1. The battery protection bottom plate 1 is disposed below the battery pack 3, and a buffer area 4 is formed between the battery pack 3 and the battery protection bottom plate 1.

[0089] By adopting the above-mentioned battery protection bottom plate 1, the composite protective structure for a battery pack can ensure a thin overall thickness, while effectively ensuring the protective strength and good corrosion resistance of the battery protection bottom plate 1.

[0090] In some embodiments, the battery pack 3 includes a tray 31 and a battery disposed on the tray 31 .

[0091] In different embodiments, the buffer area 4 may be provided in different shapes between the battery pack 3 and the battery protection bottom plate 1 .

[0092] 6, in one embodiment, the bottom surface of the tray 31 is provided with an inward groove to form a buffer area 4, and the battery protection bottom plate 1 has a flat plate shape. The battery protection bottom plate 1 covers the buffer area 4.

[0093] 7, in one embodiment, the frame of the battery protection bottom plate 1 is connected to the bottom surface of the tray 31, and the bottom surface of the tray 31 is provided with a groove on the inside. The battery protection bottom plate 1 protrudes in a direction facing away from the tray 31, forming a buffer area 4 between the tray 31 and the battery protection bottom plate 1.

[0094] 8, in one embodiment, the frame of the battery protection bottom plate 1 is connected to the bottom surface of the tray 31, and the bottom surface of the tray 31 is a flat surface. The battery protection bottom plate 1 protrudes in a direction facing away from the tray 31 to form a buffer area 4 between the tray 31 and the battery protection bottom plate 1.

[0095] In some embodiments, the buffer region 4 is filled with a buffer layer 2, which is selected from a honeycomb material or a rigid foam material.

[0096] The honeycomb material or hard foam material can absorb the crushing deformation space of the battery protection bottom plate under strong external impact, cushion and absorb part of the energy of the strong external impact, and prevent the compressive deformation of the battery protection bottom plate 1 from impacting the internal battery core of the battery pack 3, thereby further protecting the battery pack 3.

[0097] In some embodiments, the honeycomb material is selected from a polypropylene (PP) honeycomb material or an aluminum honeycomb material, and the rigid foam material is selected from a polyurethane (PU) rigid foam material, a polyethylene terephthalate (PET) rigid foam material, a polymethacrylimide (PMI) rigid foam material, a polyvinyl chloride (PVC) rigid foam material, a PET rigid foam material, a modified polypropylene (MPP) rigid foam material, a polylactic acid (PLA) rigid foam material, a polyimide (PI) rigid foam material, or a reinforced thermoplastic polyurethane (EPTU) rigid foam material.

[0098] Another embodiment of the present disclosure provides a vehicle including the above-described battery protective bottom plate or composite protective structure for a battery pack.

[0099] The present disclosure is further explained below by means of embodiments. [Table 1]

[0100] Embodiment 1 This embodiment is used to illustrate a composite protective structure for a battery pack according to the present disclosure, which includes a battery pack, a buffer layer, and a battery protective bottom plate. The battery protective bottom plate includes a metal plate, a protective layer, a fiber-reinforced resin frame, and a fiber-reinforced resin layer. The metal plate is a galvanized steel plate. The protective layer is made of a fiber-reinforced resin material. The metal plate is located between the protective layer and the fiber-reinforced resin layer. The fiber-reinforced resin layer is located below the metal plate, and the metal plate is located inside the fiber-reinforced resin frame. The top surface of the fiber-reinforced resin frame is integrally connected to the protective layer, and the bottom surface of the fiber-reinforced resin frame is integrally connected to the fiber-reinforced resin layer. The battery protective bottom plate is disposed below the battery pack, and a buffer area is formed between the battery pack and the battery protective bottom plate. The buffer area is filled with a buffer layer, and the frame of the battery protective bottom plate is attached to the bottom surface of the battery pack by rivets.

[0101] The thickness d1 of the fiber reinforced resin layer is 1.6 mm. The thickness of the protective layer is 1.5 mm. The thickness d2 of the metal plate is 1.2 mm. The breaking elongation ε2 of the metal plate is 18%, and the breaking elongation ε0 of the fiber reinforced resin layer is 3%. The tensile strength σ2 of the metal plate is 780 MPa, and the tensile strength σ0 of the fiber reinforced resin layer is 380 MPa.

[0102] Embodiments 2 to 20 Embodiments 2 to 20 are used to illustrate the composite protective structure for a battery pack according to the present disclosure, and include most of the structure in embodiment 1, except that the metal plate and fiber-reinforced resin layer provided in each of embodiments 2 to 20 in Table 1 are used.

[0103] Comparative Examples 1 to 5 Comparative Examples 1 to 5 are used to compare and illustrate the composite protective structure for a battery pack according to the present disclosure, and include most of the structure in Embodiment 1, but differ in that the metal plate and fiber-reinforced resin layer provided in each of Comparative Examples 1 to 5 in Table 1 are used.

[0104] Performance Test The performance of the composite protective structures for battery packs according to the above-described embodiment and comparative example was tested as follows.

[0105] 1. A ball was used as the impact body to strike the battery protection bottom plate of each battery pack composite protection structure, simulating the operating conditions of the entire vehicle being struck by a foreign object. The ball had a diameter of 25 mm, a weight of 10 kg, an impact energy of 300 J, and an impact speed of 8.5 m / s. The center of the battery protection bottom plate and four points around the center were selected as impact points, and five impacts were applied.

[0106] The amount of dent deformation of the battery pack tray was measured at each impact point, and the impact point with the largest amount of dent deformation was selected as the amount of dent deformation of the battery pack tray. Generally, the amount of dent deformation from an impact with an energy of 300J is required to be 3mm or less.

[0107] A vernier caliper was used to measure the diameter of the chalked area on the battery protection bottom plate after it was impacted. Each single impact point was measured three times and the average value was calculated. The impact point with the largest diameter of the chalked area was selected and taken as the chalked diameter of the fiber-reinforced resin layer as the surface layer. The grading criteria for the degree of chalking are as follows:

[0108] R1: The choking diameter of the fiber-reinforced resin layer as the surface layer is less than 2 mm, and the metal plate is not exposed.

[0109] R2: The choking diameter of the fiber-reinforced resin layer as the surface layer is less than 5 mm, and the metal plate is not exposed.

[0110] R3: The choking diameter of the fiber-reinforced resin layer as the surface layer is less than 8 mm, and the metal plate is not exposed.

[0111] R4: The choking diameter of the fiber-reinforced resin layer as the surface layer is less than 10 mm, and the metal plate is not exposed.

[0112] R5: The choking diameter of the fiber-reinforced resin layer exceeds 10 mm, exposing the metal plate.

[0113] 2. The composite protective structure for battery packs was placed on a vibration table and subjected to simulated vibrations of 300,000 kilometers to check whether the joints were damaged and whether the battery protection bottom plate was delaminated after the vibrations.

[0114] 300,000 km simulated vibration test: In accordance with the requirements of GB / T 2423.43, the test object was placed on a vibration table and the torque at each point was tested and recorded. Vibration tests were conducted in three directions. For the test procedure, please refer to GB / T 2423.56 with the following specific test conditions:

[0115] First, random vibration was performed in the Z direction for 21 hours (the random vibration conditions are shown in Table 2), and then vibration at a fixed frequency was performed in the Z direction for 1 hour (fixed frequency vibration conditions: fixed frequency 24 Hz, fixed frequency amplitude 1 g).

[0116] Next, random vibration was performed in the Y direction for 21 hours (random vibration conditions are shown in Table 2), and then vibration at a fixed frequency was performed in the Y direction for 1 hour (fixed frequency vibration conditions: fixed frequency 24 Hz, fixed frequency amplitude 1 g).

[0117] Furthermore, after random vibration was performed in the X direction for 21 hours (random vibration conditions are shown in Table 2), vibration at a fixed frequency was performed in the X direction for 1 hour (fixed frequency vibration conditions: fixed frequency 24 Hz, fixed frequency amplitude 1 g).

[0118] PSD stands for Power Spectral Density and represents the power spectral density of vibration at a certain frequency. The rms value represents the total vibration acceleration and provides feedback on the strength of the vibration. [Table 2]

[0119] The test results obtained are entered in Table 3. [Table 3]

[0120] As can be seen from the test results in Table 3, the thickness d1 of the fiber reinforced resin layer, the thickness d2 of the metal plate, the breaking elongation ε2 of the metal plate, the tensile strength σ2 of the metal plate, the breaking elongation ε0 of the fiber reinforced resin layer, and the tensile strength σ0 of the fiber reinforced resin layer are

number

[0121] The foregoing description is merely a preferred embodiment of the present disclosure and is not intended to limit the present disclosure. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present disclosure shall fall within the protection scope of the present disclosure. [Explanation of symbols]

[0122] 1 Battery protection bottom plate 11 Protective layer 111 First fiber reinforced prepreg unidirectional tape 112 First fiber fabric reinforced prepreg 12 metal plate 13 Fiber-reinforced resin frame 14 Fiber reinforced resin layer 15 Mounting holes 2 Buffer layer 3 Battery pack 31 Tray 4 Buffer area

Claims

1. A battery protective bottom plate comprising a protective layer (11), a metal plate (12), and a fiber-reinforced resin layer (14), wherein the metal plate (12) is located between the protective layer (11) and the fiber-reinforced resin layer (14), and the metal plate (12) and the fiber-reinforced resin layer (14) satisfy the following conditions: [Equation 1] Here, d １ is the thickness (mm) of the fiber reinforced resin layer (14), d ２ is the thickness (mm) of the metal plate (12), ε ２ is the breaking elongation of the metal plate (12), σ ２ is the tensile strength (MPa) of the metal plate (12), ε ０ is the breaking elongation of the fiber reinforced resin layer (14), σ ０ is the tensile strength (MPa) of the fiber reinforced resin layer (14), The thickness d 1 of the fiber reinforced resin layer (14) is 0.5 mm to 2.1 mm, The thickness d 2 of the metal plate (12) is 0.6 mm to 1.2 mm; The breaking elongation ε 2 of the metal plate (12) is 6% to 23%, The tensile strength σ 2 of the metal plate (12) is 560 MPa to 1180 MPa, The breaking elongation ε 0 of the fiber reinforced resin layer (14) is 2% to 9%, The tensile strength σ 0 of the fiber reinforced resin layer (14) is 200 MPa to 405 MPa.

2. The metal plate (12) and the fiber-reinforced resin layer (14) satisfy the following conditions: [Equation 2] 2. The battery protective bottom plate according to claim 1.

3. 2. The battery protective bottom plate according to claim 1, wherein the material of the protective layer (11) is selected from a fiber-reinforced resin material, a resin coating, or an electrophoretic coating.

4. The battery protective bottom plate according to claim 1, wherein the thickness of the protective layer (11) is 0.4 mm to 1.6 mm.

5. 5. The battery protective bottom plate according to claim 1, further comprising a fiber-reinforced resin frame (13), wherein the metal plate (12) and the fiber-reinforced resin frame (13) are positioned between the protective layer (11) and the fiber-reinforced resin layer (14), the metal plate (12) is positioned inside the fiber-reinforced resin frame (13), an upper surface of the fiber-reinforced resin frame (13) is integrally connected to the protective layer (11), and a bottom surface of the fiber-reinforced resin frame (13) is integrally connected to the fiber-reinforced resin layer (14).

6. 6. The battery protection bottom plate according to claim 5, wherein a plurality of mounting holes (15) are arranged at intervals inside the edge of the battery protection bottom plate (1), and the mounting holes (15) extend through the protective layer (11), the fiber-reinforced resin frame (13), and the fiber-reinforced resin layer (14) in that order.

7. 6. The battery protective bottom plate according to claim 5, wherein the protective layer (11), the fiber-reinforced resin frame (13), and the fiber-reinforced resin layer (14) are each independently selected from a glass fiber-reinforced polyamide resin member, a glass fiber-reinforced polypropylene resin member, a glass fiber-reinforced polyethylene resin member, a glass fiber-reinforced polycarbonate resin member, or a glass fiber-reinforced polystyrene resin member.

8. 6. The battery protective bottom plate according to claim 5, wherein the protective layer (11), the fiber reinforced resin frame (13), and the fiber reinforced resin layer (14) are each a glass fiber reinforced resin member, the glass fiber reinforced resin member contains 60% to 70% glass fiber, and the glass fiber has an alkali content of less than 0.8%.

9. said protective layer (11) comprising a plurality of layers of a first fiber-reinforced prepreg laminated together; and / or the fiber-reinforced resin frame (13) comprises a plurality of layers of a second fiber-reinforced prepreg laminated together; and / or 6. The battery protective bottom plate of claim 5, wherein the fiber reinforced resin layer (14) comprises a plurality of layers of a third fiber reinforced prepreg laminated together.

10. 5. The battery protective bottom plate according to claim 1, wherein the metal plate (12) is a steel plate, and a zinc-plated layer, a zinc-plated iron alloy layer, or an electrophoretic coating protective layer is disposed on the outer surface of the steel plate.

11. A composite protective structure (10) for a battery pack, comprising: a battery pack (3); and the battery protective bottom plate (1) according to claim 1, wherein the battery protective bottom plate (1) is disposed below the battery pack (3), and a buffer area (4) is formed between the battery pack (3) and the battery protective bottom plate (1).

12. 12. The composite protective structure for a battery pack according to claim 11, wherein the buffer region (4) is filled with a buffer layer (2), and the buffer layer (2) is selected from a honeycomb material or a rigid foam material.

13. A vehicle comprising a battery protective bottom plate (1) according to any one of claims 1 to 4 or a composite protective structure for a battery pack according to claim 11 or 12.

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