Battery protection floor plate, battery pack composite protection structure, and vehicle

Abstract

The present application provides a battery protection bottom plate comprising a protective layer, a metal plate, and a fiber-reinforced resin layer to solve the problem that the corrosion resistance of existing battery pack bottom protection plates is insufficient due to peeling of the surface PVC layer upon impact. The metal plate is positioned between the protective layer and the fiber-reinforced resin layer, and the metal plate and the fiber-reinforced resin layer satisfy the condition of the following Equation I. In addition, the present application further discloses a battery pack composite protection structure including a battery protection bottom plate and a vehicle.

Description

Technology Field

[0001] Cross-reference regarding related applications

[0002] The present disclosure claims priority and interest to Chinese Patent Application No. 202210612280.6 filed on May 31, 2022. The entire contents of said application are incorporated herein by reference.

[0003] field

[0004] The present disclosure relates to the technical field of vehicle batteries, and more specifically to a battery protection base plate, a battery pack composite protection structure, and a vehicle. Background Technology

[0005] With the rapid advancement of electric vehicles, public demand for their safety is steadily increasing. As power battery packs are used as the power source for electric vehicles, the importance of their safety is self-evident. Battery packs are typically located at the bottom of the vehicle body and are bolted to the body. The bottom surface of the battery pack is exposed to the outside. During normal driving, the bottom of the battery pack is vulnerable to collisions, which can lead to casing damage and protection failure. Stones kicked up from the road surface while driving can also affect the battery pack. To cope with complex operating conditions, a protective plate is typically placed on the bottom of the battery pack to protect it. The protective plate is usually made of steel, and a PVC layer is sprayed onto the bottom surface to resist impact and corrosion. However, the overall impact resistance of existing protective plates still needs improvement. Specifically, under impact from an external hard object, the PVC layer on the bottom surface of the protective plate is susceptible to choking and detaches from the surface of the protective plate, subsequently exposing the inner steel plate and affecting the corrosion resistance of the protective plate.

[0006] To address the problem where the surface PVC layer of a conventional battery pack bottom protection plate detaches upon impact, resulting in insufficient corrosion resistance, the present disclosure provides a battery protection bottom plate, a battery pack composite protection structure, and a vehicle.

[0007] The technical solution adopted by the present disclosure to solve the above technical problem is as follows.

[0008] In a first embodiment, the present disclosure provides a battery protection bottom plate comprising a protective layer, a metal plate, and a fiber-reinforced resin layer. The metal plate is positioned between the protection plate and the fiber-reinforced resin layer, and the metal plate and the fiber-reinforced resin layer satisfy the following conditions:

[0009]

[0010] Here, d1 is the thickness of the fiber-reinforced resin layer in mm;

[0011] d2 is the thickness of the metal plate in mm;

[0012] ε2 is the fracture elongation of the metal plate;

[0013] σ2 is the tensile strength of a metal plate in MPa units;

[0014] ε0 is the elongation at break of the fiber-reinforced resin layer;

[0015] σ0 is the tensile strength of the fiber-reinforced resin layer in MPa units.

[0016] In some embodiments, the metal plate and the fiber-reinforced resin layer satisfy the following conditions:

[0017]

[0018] In some embodiments, the thickness (d1) of the fiber-reinforced resin layer is in the range of 0.6 mm to 2.0 mm.

[0019] In some embodiments, the thickness (d2) of the metal plate is in the range of 0.7 mm to 1.6 mm.

[0020] In some embodiments, the fracture elongation (ε2) of the metal plate is in the range of 5% to 20%.

[0021] In some embodiments, the tensile strength (σ2) of the metal plate is in the range of 590 MPa to 1180 MPa.

[0022] In some embodiments, the elongation at break (ε0) of the fiber-reinforced resin layer is in the range of 2.5% to 8%.

[0023] In some embodiments, the tensile strength (σ0) of the fiber-reinforced resin layer is in the range of 240 MPa to 380 MPa.

[0024] In some embodiments, the material of the protective layer is selected from fiber-reinforced resin material, resin coating, or electrophoretic coating.

[0025] In some embodiments, the thickness of the protective layer is in the range of 0.4 mm to 1.6 mm.

[0026] In some embodiments, the battery protection bottom plate further includes a fiber-reinforced resin frame. The metal plate and the fiber-reinforced resin frame are positioned between the protective layer and the fiber-reinforced resin layer, and the metal plate is positioned 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.

[0027] In some embodiments, a plurality of mounting holes are spaced apart on the inner edge of the battery protection bottom plate, and the mounting holes sequentially penetrate the protection layer, the fiber-reinforced resin frame, and the fiber-reinforced resin layer.

[0028] In some embodiments, the protective layer, the fiber-reinforced resin frame, and the fiber-reinforced resin layer may each be 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.

[0029] In some embodiments, 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 glass fibers in a content ranging from 60% to 70% by weight, and the glass fibers may have an alkali content of less than 0.8% by weight.

[0030] In some embodiments, the protective layer comprises a plurality of first fiber-reinforced prepregs stacked together.

[0031] In some embodiments, the fiber-reinforced resin frame comprises a plurality of layers of second fiber-reinforced prepregs laminated together.

[0032] In some embodiments, the fiber-reinforced resin layer comprises a plurality of layers of third fiber-reinforced prepregs stacked together.

[0033] In some embodiments, the metal plate is a steel plate, and a zinc plating layer, a zinc-plated iron alloy layer, or an electrophoretic paint protective layer is arranged on the outer surface of the steel plate.

[0034] In another embodiment, the present disclosure provides a battery pack composite protection structure comprising a battery pack and a battery protection base plate as described above. The battery protection base plate is arranged below the battery pack, and a buffer zone is formed between the battery pack and the battery protection base plate.

[0035] In some embodiments, the buffer zone is filled with a buffer layer, and the buffer layer is selected from honeycomb material or rigid foam material.

[0036] In another aspect, the present disclosure provides a vehicle comprising a battery protection floor plate or a battery pack composite protection structure as described above.

[0037] In a battery protection bottom plate according to the present disclosure, a fiber-reinforced resin layer is composited onto the surface of a metal plate, and the fiber-reinforced resin layer is used as a bottom surface coating structure of the metal plate, thereby preventing the metal plate from coming into direct contact with air and external moisture and protecting the metal plate from corrosion. In addition, the fiber-reinforced resin has good mechanical strength, so the stiffness and strength of the metal plate are effectively improved, and the metal plate has higher impact resistance.

[0038] Furthermore, the inventors discovered that when a fiber-reinforced resin layer is matched with a metal plate, a battery protection base plate with excellent impact resistance can be obtained in some matching groups, whereas the surface of the fiber-reinforced resin layer is damaged in some matching groups. Through additional experiments, it was confirmed that the tensile strength and elongation at break of the selected fiber-reinforced resin layer must have a constant correspondence with the tensile strength and elongation at break of the metal plate in order to ensure adhesion between the fiber-reinforced resin layer and the metal plate without damage when the battery protection base plate is impacted by external energy. The following relationships were summarized with reference to the thicknesses of the fiber-reinforced resin layer and the metal plate.

[0039]

[0040] When the thickness (d1) of the fiber-reinforced resin layer, the thickness (d2) of the metal plate, the fracture elongation (ε2) of the metal plate, the fracture 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 protection bottom plate with excellent impact resistance and corrosion resistance is obtained. Brief explanation of the drawing

[0041] FIG. 1 is a schematic structural diagram of a battery protection bottom plate according to the present disclosure. FIG. 2 is a schematic structural diagram of a different first fiber-reinforced prepreg unidirectional tape of a protective layer according to the present disclosure. FIG. 3 is a schematic structural diagram of a different first fiber fabric reinforced prepreg of a protective layer according to the present disclosure. FIG. 4 is a schematic diagram of a battery pack composite protection structure according to the present disclosure. Figure 5 is a schematic enlarged view of part A of Figure 4. FIG. 6 is a schematic cross-sectional view of the bottom of a battery pack composite protection structure according to one embodiment of the present disclosure. FIG. 7 is a schematic cross-sectional view of the bottom of a battery pack composite protection structure according to another embodiment of the present disclosure. FIG. 8 is a schematic cross-sectional view of the bottom of a battery pack composite protection structure according to another embodiment of the present disclosure. Specific details for implementing the invention

[0042] To clarify the technical problem to be solved, the technical means of solution, and the effects of the present disclosure, the present disclosure is described in detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described in this specification are used merely to explain the present disclosure and are not intended to limit the present disclosure.

[0043] In the description of the present disclosure, terms such as "upper," "lower," "top," "bottom," "inside," and "outside" are to be understood as presupposing the directional or positional relationships depicted in the drawings. They do not indicate or imply that the mentioned device or component has a specific direction or is configured and operated in a specific direction, but are merely for the convenience and simplification of the description of the present disclosure and should not be interpreted as limiting the present disclosure. In the description of the present disclosure, unless specifically stated otherwise, "plural / multiple" means two or more.

[0044] As illustrated in FIG. 1, one embodiment of the present disclosure provides a battery protection bottom plate (1) comprising a protective layer (11), a metal plate (12), and a fiber-reinforced resin layer (14). The metal plate (12) is positioned 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.

[0045]

[0046] Here, d1 is the thickness of the fiber-reinforced resin layer (14) in mm units;

[0047] d2 is the thickness of the metal plate (12) in mm;

[0048] ε2 is the fracture elongation of the metal plate (12);

[0049] σ2 is the tensile strength of the metal plate (12) in MPa units;

[0050] ε0 is the fracture elongation of the fiber-reinforced resin layer (14);

[0051] σ0 is the tensile strength of the fiber-reinforced resin layer (14) in MPa units.

[0052] The fiber-reinforced resin layer (14) as a bottom surface coating structure of the metal plate (12) prevents the metal plate (12) from coming into direct contact with air and external moisture, thereby protecting the metal plate (12) from corrosion. In addition, since the fiber-reinforced resin has good mechanical strength, the rigidity and strength of the metal plate (12) are effectively improved, so the metal plate has higher impact resistance.

[0053] Additionally, the inventors discovered that when the fiber-reinforced resin layer (14) is matched with the metal plate (12), a battery protection base plate (1) with excellent impact resistance can be obtained in some matching groups, while the surface of the fiber-reinforced resin layer (14) is damaged in some matching groups. Through further experiments, it was confirmed that the tensile strength and elongation at break of the selected fiber-reinforced resin layer (14) must have a specific corresponding relationship with the tensile strength and elongation at break of the metal plate (12) so that the battery protection base plate (1) is not damaged when impacted by external energy, and adhesion between the fiber-reinforced resin layer (14) and the metal plate (12) can be secured. With reference to the thicknesses of the fiber-reinforced resin layer (14) and the metal plate (12), the following relationship was summarized.

[0054]

[0055] When the thickness (d1) of the fiber-reinforced resin layer (14), the thickness (d2) of the metal plate (12), the fracture elongation (ε2) of the metal plate (12), the fracture 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 conditions, a battery protection bottom plate (1) with excellent impact resistance and corrosion resistance is obtained.

[0056] In some embodiments, the metal plate (12) and the fiber-reinforced resin layer (14) satisfy the following conditions.

[0057]

[0058] By defining the above relationship, the effect of 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. This is advantageous for preventing the fiber-reinforced resin layer (14) on the surface from falling off when the fiber-reinforced resin layer receives an external impact, thereby ensuring corrosion resistance of the battery protection bottom plate (1) and extending its lifespan.

[0059] In some embodiments, the thickness (d1) of the fiber-reinforced resin layer (14) is in the range of 0.6 mm to 2.0 mm.

[0060] Specifically, the thickness (d1) of the fiber-reinforced resin layer (14) may be 0.6mm, 0.7mm, 0.8mm, 0.9mm, 1.0mm, 1.1mm, 1.2mm, 1.3mm, 1.4mm, 1.5mm, 1.6mm, 1.8mm, or 2.0mm.

[0061] The thickness (d1) of the fiber-reinforced resin layer (14) is related to the corrosion resistance of the metal plate (12) to the outside air and water vapor, and affects the bonding strength with the metal plate (12) and the overall strength after composite formation with the metal plate (12). When the thickness (d1) of the fiber-reinforced resin layer (14) is within the above range, it can prevent detachment from the surface of the metal plate (12) under high-energy impact, and effectively maintain the corrosion-prevention and strength-enhancing effects of the metal plate (12).

[0062] In some embodiments, the thickness (d2) of the metal plate (12) is in the range of 0.7 mm to 1.6 mm.

[0063] Specifically, the thickness (d2) of the metal plate (12) may be 0.7mm, 0.8mm, 0.9mm, 1.0mm, 1.1mm, 1.2mm, 1.3mm, 1.4mm, 1.5mm, or 1.6mm.

[0064] 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, the protection strength gradually increases as the thickness of the metal plate (12) increases, but the material cost also gradually increases and the ground clearance of the vehicle floor decreases. 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 secured, costs can be effectively controlled, distance from the ground can be secured, and the vehicle's weight can be easily controlled.

[0065] In some embodiments, the fracture elongation (ε2) of the metal plate (12) is in the range of 5% to 20%.

[0066] Specifically, the fracture 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%.

[0067] In some embodiments, the tensile strength (σ2) of the metal plate (12) is in the range of 590 MPa to 1180 MPa.

[0068] 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.

[0069] The tensile strength (σ2) and elongation at break (ε2) of the metal plate (12) can be tested using the GB / T 228.1 - 2010 Metal Materials - Tensile Test - Part 1: Room Temperature Test Method. The metal plate (12), which serves as a primary protective component in the battery protection base plate (1), faces complex impact conditions, and the tensile strength (σ2), as a strength index of the metal plate (12), affects the deformation resistance of the metal plate (12) within the elastic deformation range of the metal plate. As the tensile strength (σ2) increases, the metal plate (12) can resist higher impacts without irreversible deformation. The elongation at break (ε2) affects the fracture resistance of the metal plate (12) after deformation. As the elongation at break (ε2) increases, the metal plate (12) can resist higher impacts without cracking. However, generally, a higher tensile strength (σ2) of the metal plate (12) exhibits a lower elongation at break (ε2). When the tensile strength (σ2) and the elongation at break (ε2) are within the above range, the influence of different parameters on the protective performance of the metal plate (12) can be effectively considered, and the impact strength and crack resistance of the metal plate (12) can be secured.

[0070] In some embodiments, the fracture elongation (ε0) of the fiber-reinforced resin layer (14) is in the range of 2.5% to 8%.

[0071] Specifically, the fracture 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%.

[0072] In some embodiments, the tensile strength (σ0) of the fiber-reinforced resin layer (14) is in the range of 240 MPa to 380 MPa.

[0073] 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.

[0074] The fracture elongation (ε0) of the fiber-reinforced resin layer (14) and the tensile strength (σ0) of the fiber-reinforced resin layer (14) can be tested by measuring the tensile properties of fiber-reinforced plastic composites according to GB / T 1447-2005. Type I samples are suitable for fiber-reinforced thermoplastic plates and are manufactured according to Type I samples specified in national test standards. The fiber-reinforced resin layer (14) is the surface layer of the battery protection base plate (1) that comes into direct contact with the object of impact upon impact, and an increase in tensile strength (σ0) is advantageous for improving the deformation resistance of the fiber-reinforced resin layer (14). An increase in tensile strength (σ0) may lead to a decrease in fracture elongation (ε0), which affects the adhesion between the fiber-reinforced resin layer (14) and the metal plate (12), and may cause delamination upon impact. When the tensile strength (σ0) and elongation at break (ε0) of the fiber-reinforced resin layer (14) are within the above range, the fiber-reinforced resin layer (14) can effectively resist external impact without peeling or detachment.

[0075] In actual applications, the above six parameters are interrelated and cannot be separated 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) does not match well with the tensile strength (σ0) of the fiber-reinforced resin layer (14), it is easy to induce asynchronous vibration, which is highly likely to cause delamination. If the fracture elongation (ε2) of the metal plate (12) does not match well with the fracture elongation (ε0) of the fiber-reinforced resin layer (14), the fiber-reinforced resin layer (14) is prone to chalking by impact. The tensile strength (σ2) of the metal plate (12) is related to the fracture elongation (ε2) of the metal plate (12), and the tensile strength (σ0) of the fiber-reinforced resin layer (14) is related to the fracture elongation (ε0) of the fiber-reinforced resin layer (14). If the thickness (d2) of the metal plate (12) and the thickness (d1) of the fiber-reinforced resin layer (14) increase, 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) increase accordingly. This does not help meet the requirements for vehicle lightweighting and cost control, and leads to a reduction in the distance between the vehicle and the ground. This is not advantageous for meeting the requirements for vehicle lightweighting and cost control, and leads to a reduction in the vehicle's ground clearance. Therefore, the following relationship

[0076]

[0077] Through this, the combined effect of each factor on the protection performance of the battery pack (3) is advantageous for improving the impact resistance of the battery protection base plate (1) and prevents interlayer delamination and surface choking upon impact.

[0078] In some embodiments, the material of the protective layer (11) is selected from fiber-reinforced resin material, resin coating, or electrophoretic coating. The protective layer (11) is configured to improve the corrosion resistance and composite strength of the metal plate (12).

[0079] In some embodiments, the thickness of the protective layer (11) is in the range of 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 water vapor penetration resistance and the bonding strength between the metal plate (12) and the protective layer (11). 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 between the metal plate (12) and the protective layer (11) can be improved.

[0080] In some embodiments, the battery protection bottom plate (1) further includes a fiber-reinforced resin frame (13). The metal plate (12) and the fiber-reinforced resin frame (13) are positioned between the protection layer (11) and the fiber-reinforced resin layer (14), and the metal plate (12) is positioned inside the fiber-reinforced resin frame (13). The top surface of the fiber-reinforced resin frame (13) is integrally connected to the protection layer (11), and the bottom surface of the fiber-reinforced resin frame (13) is integrally connected to the fiber-reinforced resin layer (14).

[0081] The fiber-reinforced resin frame (13) is arranged around the perimeter of the metal plate (12) as a frame connection transition member for the protective layer (11) and the fiber-reinforced resin layer (14). This can effectively offset the effect of the thickness of the metal plate (12) on the frame connection of the protective layer (11) and the fiber-reinforced resin layer (14), secure the strength of the frame of the battery protection base plate (1), make it easier to use the frame of the battery protection base plate (1) as a mounting structure for the battery, and improve the impact resistance of the battery protection base plate.

[0082] As shown in FIGS. 4 and 5, in some embodiments, a plurality of mounting holes (15) are spaced apart and formed on the inner edge of the battery protection base plate (1), and the mounting holes (15) sequentially penetrate the protection layer (11), the fiber-reinforced resin frame (13), and the fiber-reinforced resin layer (14).

[0083] The mounting holes (15) are configured to mount and fasten the battery protection bottom plate (1) to the bottom of the battery pack (3). The mounting holes (15) are provided on the inner edge of the battery protection bottom plate (1) and penetrate the protective layer (11), the fiber-reinforced resin frame (13), and the fiber-reinforced resin layer (14) in sequence, thereby preventing the mounting holes (15) from penetrating the metal plate (12) and preventing the metal plate (12) from being exposed in the mounting holes (15) and causing corrosion. Additionally, the fiber-reinforced resin frame (13) is advantageous for improving the overall thickness and tensile shear strength of the mounting location and has sufficient mounting stability.

[0084] A number of mounting holes (15) are provided along the circumference of the metal plate (12) to evenly distribute the upper gravity and bottom impact force on the metal plate (12).

[0085] Specifically, when mounted, a connecting member is provided to penetrate the mounting hole (15) to secure the battery protection bottom plate (1) to the bottom of the battery pack (3). The connecting member is a rivet, screw, or bolt.

[0086] In different embodiments, the resins of the protective layer (11), the fiber-reinforced resin frame (13), and the 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 plastics, phenol, cyanate esters, imides (e.g., polyimide, bismaleimide (BMI) and polyetherimide), polypropylene, polyesters, benzoxazine, polybenzimidazole, polybenzothiazole, polyamides, polyamideimide, polysulfones, polyethersulfones, polycarbonates, polyethylene terephthalate and polyether ketones (e.g., polyether ketone (PEK), polyetherether ketone (PEEK) and polyether ketone ketone (PEKK)), and combinations thereof.

[0087] The fibers of the protective layer (11), the fiber-reinforced resin frame (13), and the fiber-reinforced resin layer (14) can each be independently selected from the group consisting of glass fibers, aramid fibers, carbon fibers, graphite fibers, boron fibers, aromatic polyamide fibers, and mixtures thereof.

[0088] The fibers of the protective layer (11), the fiber-reinforced resin frame (13), and the fiber-reinforced resin layer (14) may be impregnated in the resin in the form of short fibers, long fibers, nonwoven fabric, unidirectional reinforcing fiber substrate, fabric, etc.

[0089] In some embodiments, the protective layer (11), the fiber-reinforced resin frame (13), and the fiber-reinforced resin layer (14) may each be 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.

[0090] 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, and the same resin material can ensure material affinity between different layers, thereby ensuring a high degree of bonding between different layers and improving overall strength.

[0091] In some embodiments, 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 glass fibers in an amount of 60% to 70% by weight, which is advantageous for improving the material strength of the protective layer (11), the fiber-reinforced resin frame (13), and the fiber-reinforced resin layer (14).

[0092] In some embodiments, the alkali content of the glass fiber is less than 0.8% by weight.

[0093] If the alkali content of the glass fiber is less than 0.8% by weight, 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 deterioration of the material's performance after long-term use is slowed down.

[0094] In some embodiments, the glass fiber is selected from E-glass fiber or S-glass fiber.

[0095] In some embodiments, the protective layer (11) comprises a plurality of layers of first fiber-reinforced prepregs stacked together.

[0096] In some embodiments, the fiber-reinforced resin frame (13) comprises a plurality of layers of second fiber-reinforced prepregs stacked together.

[0097] In some embodiments, the fiber-reinforced resin layer (14) comprises a plurality of layers of third fiber-reinforced prepregs stacked together.

[0098] As illustrated in FIG. 2, in one embodiment, the protective layer (11) comprises a plurality of layers of first fiber-reinforced prepreg unidirectional tapes (111) stacked together. The fiber arrangement directions of two adjacent layers of the first fiber-reinforced prepreg unidirectional tapes (111) are staggered by approximately 90°, and the allowable ply angle deviation range of two adjacent layers of the first fiber-reinforced prepreg unidirectional tapes (111) is ± 20°.

[0099] The fibers of each first fiber-reinforced prepreg unidirectional tape (111) are provided in a unidirectional manner, and when subjected to tensile force along the fiber extension direction, the fibers of the first fiber-reinforced prepreg unidirectional tape (111) can effectively withstand the tensile force. By staggering the fiber arrangement direction of adjacent first fiber-reinforced prepreg unidirectional tapes (111) by approximately 90°, the stress uniformity in each direction of the protective layer (11) is improved.

[0100] The fiber-reinforced resin frame (13) comprises multiple layers of second fiber-reinforced prepreg unidirectional tapes stacked together. The fibers of each second fiber-reinforced prepreg unidirectional tape are arranged in a unidirectional manner. The fiber arrangement directions of two adjacent layers of the second fiber-reinforced prepreg unidirectional tape are staggered by approximately 90°, and the allowable ply angle deviation range of two adjacent layers of the second fiber-reinforced prepreg unidirectional tape is ± 20°.

[0101] The fiber-reinforced resin layer (14) comprises multiple layers of third fiber-reinforced prepreg unidirectional tapes stacked together. The fibers of each third fiber-reinforced prepreg unidirectional tape are arranged in a unidirectional manner. The fiber arrangement directions of two adjacent layers of the third fiber-reinforced prepreg unidirectional tape are staggered by approximately 90°, and the allowable ply angle deviation range of two adjacent layers of the third fiber-reinforced prepreg unidirectional tape is ± 20°.

[0102] 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), so the explanation is not repeated.

[0103] As illustrated in FIG. 3, in another embodiment, the protective layer (11) comprises a plurality of layers of first fiber fabric reinforced prepregs (112) stacked together, and the fibers of each first fiber fabric reinforced prepreg (112) form a fabric in an alternating shape.

[0104] The fiber-reinforced resin frame (13) comprises multiple layers of second fiber fabric-reinforced prepregs stacked together, and the fibers of each second fiber fabric-reinforced prepreg form a fabric in an alternating shape.

[0105] The fiber-reinforced resin layer (14) comprises a plurality of layers of third fiber fabric-reinforced prepregs stacked together, and the fibers of each third fiber fabric-reinforced prepreg form a fabric in an alternating shape.

[0106] In some embodiments, the metal plate (12) may be 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.

[0107] In one embodiment, the metal plate (12) is a steel plate, and a zinc plating layer, a zinc-plated iron alloy layer, or an electrophoretic paint protective layer is arranged on the outer surface of the steel plate.

[0108] Compared to other metal materials, the steel plate used as the metal plate (12) has good tensile strength and elongation, can satisfy impact resistance requirements, and is advantageous for improving the protection effect of the battery pack (3).

[0109] A galvanized layer, a galvanized iron alloy layer, or an electrophoretic paint protective layer is arranged on the outer surface of the steel plate to improve the corrosion resistance of the steel plate. If the protective layer (11) or the fiber-reinforced resin layer (14) is damaged, the galvanic layer or the galvanized iron alloy layer corrodes before the steel plate due to the galvanic effect achieved by the galvanic layer or the galvanized iron alloy layer and the steel plate, thereby providing a protective effect on the steel plate. The electrophoretic paint protective layer has excellent adhesion and can effectively isolate the steel plate from the external environment.

[0110] As illustrated in FIGS. 4 and FIGS. 6 to 8, another embodiment of the present disclosure provides a battery pack composite protection structure comprising a battery pack (3) and a battery protection bottom plate (1) as described above. The battery protection bottom plate (1) is arranged below the battery pack (3), and a buffer zone (4) is formed between the battery pack (3) and the battery protection bottom plate (1).

[0111] Due to the adoption of the battery protection base plate (1) described above, the battery pack composite protection structure effectively ensures protection strength and good corrosion resistance of the battery protection base plate (1) while ensuring a smaller overall thickness.

[0112] In some embodiments, the battery pack (3) includes a tray (31) and batteries arranged on the tray (31).

[0113] In different embodiments, the buffer zone (4) may be provided between the battery pack (3) and the battery protection base plate (1) in different ways.

[0114] As illustrated in FIG. 6, in one embodiment, a groove is formed inwardly on the bottom surface of the tray (31) to form a buffer zone (4), and the battery protection bottom plate (1) has a flat shape. The battery protection bottom plate (1) covers the buffer zone (4).

[0115] As shown in FIG. 7, the frame of the battery protection bottom plate (1) is connected to the bottom surface of the tray (31), and a groove is formed inside the bottom surface of the tray (31). The battery protection bottom plate (1) protrudes in a direction away from the tray (31) to form a buffer zone (4) between the tray (31) and the battery protection bottom plate (1).

[0116] As illustrated in FIG. 8, in one embodiment, the frame of the battery protection base plate (1) is connected to the bottom surface of the tray (31), and the bottom surface of the tray (31) is flat. The battery protection base plate (1) protrudes in a direction away from the tray (31) to form a buffer zone (4) between the tray (31) and the battery protection base plate (1).

[0117] In some embodiments, the buffer zone (4) is filled with a buffer layer (2), and the buffer layer (2) is selected from a honeycomb material or a rigid foam material.

[0118] The honeycomb material or rigid foam material can absorb the collapse deformation space of the battery protection base plate under strong external impact, buffer and absorb part of the energy of the strong external impact, and further protect the battery pack (3) by preventing the compressive deformation of the battery protection base plate (1) from affecting the internal battery core of the battery pack (3).

[0119] In some embodiments, the honeycomb material is selected from polypropylene (PP) honeycomb material or aluminum honeycomb material; and the rigid foam material is selected from polyurethane (PU) rigid foam material, polyethylene terephthalate (PET) rigid foam material, polymethacrylimide (PMI) rigid foam material, polyvinyl chloride (PVC) rigid foam material, modified polypropylene (MPP) rigid foam material, polylactic acid (PLA) rigid foam material, polyimide (PI) rigid foam material, or expanded thermoplastic polyurethane (ETPU) rigid foam material.

[0120] Another embodiment of the present disclosure provides a vehicle comprising a battery protection floor plate or a battery pack composite protection structure as described above.

[0121] The present disclosure is further explained below by way of examples.

[0122] Thickness d1 (mm) of fiber-reinforced resin layer Thickness d2 (mm) of the metal plate Breaking elongation ε2 of a metal plate Tensile strength of metal plate σ2 (MPa) Breaking elongation ε0 of fiber-reinforced resin layer Tensile strength σ0 (MPa) of fiber-reinforced resin layer Example 1 1.6 1.2 18% 780 3% 380 1.56 Example 2 1.6 1.2 18% 780 4% 300 1.23 Example 3 1.6 1.2 18% 780 7% 240 0.62 Example 4 1.6 1.2 18% 780 6% 340 1.02 Example 5 1.6 0.8 18% 780 6% 340 1.53 Example 6 1.6 0.7 18% 780 6% 300 1.58 Example 7 1.2 0.8 18% 780 6% 300 1.04 Example 8 0.8 0.8 18% 780 6% 300 0.69 Example 9 1 0.8 18% 780 3% 380 1.46 Example 10 1 0.8 20% 590 3% 380 1.63 Example 11 1 0.8 23% 560 3% 380 1.70 Example 12 1.6 1.2 18% 780 8% 220 0.45 Example 13 1.6 0.6 18% 780 6% 300 1.85 Example 14 2 0.8 18% 780 6% 340 1.92 Example 15 0.6 0.8 18% 780 6% 280 0.49 Example 16 1 0.8 6% 1180 3% 380 0.44 Example 17 0.5 0.7 18% 780 6% 340 0.55 Example 18 2.1 1.2 18% 780 6% 340 1.34 Example 19 1.6 1.2 18% 780 2% 405 1.77 Example 20 2 0.8 18% 780 9% 200 0.59 Comparative Example 1 2 0.8 6% 1180 6% 340 0.13 Comparative Example 2 2 1 20% 560 6% 340 2.01 Comparative Example 3 0.6 1.2 18% 780 6% 340 0.38 Comparative Example 4 1.6 0.8 12% 450 4% 360 2.17 Comparative Example 5 2.2 0.8 18% 780 6% 340 2.11

[0123] Example 1

[0124] This embodiment is used to describe a battery pack composite protection structure according to the present disclosure and comprises a battery pack, a buffer layer, and a battery protection bottom plate. The battery protection bottom plate comprises 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 positioned between the protective layer and the fiber-reinforced resin layer. The fiber-reinforced resin layer is positioned below the metal plate, and the metal plate is positioned inside the fiber-reinforced resin frame. The upper surface of the fiber-reinforced resin frame is integrally connected to the protective layer, and the lower surface of the fiber-reinforced resin frame is integrally connected to the fiber-reinforced resin layer. The battery protection bottom plate is arranged below the battery pack, and a buffer zone is formed between the battery pack and the battery protection bottom plate. The buffer zone is filled with a buffer layer, and the frame of the battery protection bottom plate is mounted to the bottom frame of the battery pack by rivets.

[0125] 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 elongation at break (ε2) of the metal plate is 18%, and the elongation at break (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.

[0126] Examples 2 to 20

[0127] Examples 2 through 20 are used to describe a battery pack composite protection structure according to the present disclosure that comprises most of the structure of Example 1, but differ as follows:

[0128] The metal plate and fiber-reinforced resin layer provided in each of Examples 2 to 20 of Table 1 are used.

[0129] Comparative Examples 1 to 5

[0130] Comparative Examples 1 to 5 are used to compare and describe a battery pack composite protection structure according to the present disclosure that includes most of the structure of Example 1, but have the following differences:

[0131] The metal plate and fiber-reinforced resin layer provided in each of Comparative Examples 1 to 5 of Table 1 are used.

[0132] Performance test

[0133] The performance of the battery pack composite protection structure according to the above examples and comparative examples was tested as follows.

[0134] 1. Using a ball as an impact head, the battery protection bottom plate of each battery pack composite protection structure was impacted to simulate operating conditions where the floor of the entire vehicle is struck by foreign matter. The ball had a diameter of 25 mm, a weight of 10 kg, an impact energy of 300 J, and an impact velocity of 8.5 m / s. The center point of the battery protection bottom plate and four points around the center point were selected as impact points, and five impacts were performed.

[0135] The amount of indentation deformation of the battery pack tray at each impact point was measured, and the impact point with the maximum amount of indentation deformation was selected and indicated as the amount of indentation deformation of the battery pack tray. Generally, it is required that the amount of indentation from a 300J energy impact not exceed 3mm.

[0136] A vernier caliper was used to measure the diameter of the choking area of ​​the battery protection base plate after it was subjected to impact. Each single impact point was measured three times, and the average value was calculated. The impact point with the largest choking area diameter was selected and designated as the choking diameter of the fiber-reinforced resin layer serving as the surface layer. The criteria for the choking degree grade are as follows.

[0137] R1: The chalking diameter of the fiber-reinforced resin layer as a surface layer is less than 2 mm, and the metal plate is not exposed;

[0138] R2: The chalking diameter of the fiber-reinforced resin layer as a surface layer is less than 5 mm, and the metal plate is not exposed;

[0139] R3: The chalking diameter of the fiber-reinforced resin layer as a surface layer is less than 8 mm, and the metal plate is not exposed;

[0140] R4: The chalking diameter of the fiber-reinforced resin layer as a surface layer is less than 10 mm, and the metal plate is not exposed;

[0141] R5: The chalking area of ​​the fiber-reinforced resin layer is greater than 10 mm, and it can be confirmed that the metal plate is exposed.

[0142] 2. A battery pack composite protection structure was mounted on a vibration table and a 300,000 km driving distance simulation vibration was performed to check for damage to the joints and delamination of the battery protection bottom plate after vibration.

[0143] 300,000 km Driving Range Simulation Vibration Test: In accordance with the requirements of GB / T 2423.43, the test object was mounted on a vibration table, and the torque at each mounting point was tested and recorded. The vibration test was performed in three directions. For the test process, refer to GB / T 2423.56, which has the following specific test conditions.

[0144] First, random vibration was performed in the Z direction for 21 hours (under the random vibration conditions shown in Table 2), and then vibration was performed at a fixed frequency in the Z direction for 1 hour (fixed frequency vibration conditions: fixed frequency of 24 Hz, fixed frequency amplitude of 1 g).

[0145] Secondly, after performing random vibration in the Y direction for 21 hours (under the random vibration conditions shown in Table 2), vibration at a fixed frequency was performed in the Y direction for 1 hour (fixed frequency vibration conditions: fixed frequency of 24 Hz, fixed frequency amplitude of 1 g).

[0146] In addition, after performing random vibration in the X direction for 21 hours (under the random vibration conditions shown in Table 2), vibration at a fixed frequency was performed in the X direction for 1 hour (fixed frequency vibration conditions: fixed frequency of 24 Hz, fixed frequency amplitude of 1 g).

[0147] PSD represents the dynamic spectral density and indicates the dynamic spectral density of vibration at a given frequency. The rms value represents the comprehensive acceleration of vibration and provides feedback on vibration intensity.

[0148] X direction Y direction Z direction Frequency Hz PSD g 2 / Hz Frequency Hz PSD g 2 / Hz Frequency Hz PSD g 2 / Hz 5 0.005 5 0.002 5 0.012 11.5 0.005 10 0.004 9.5 0.012 13 0.01726 14 0.01206 11 0.0198 21.5 0.005 34 0.001751 78 0.1193 30 0.005 40 0.00857 80 0.0009 35 0.0032 46 0.001 100 0.0009 38 0.008383 74 0.0008782 200 0.00006 48 0.00132 77 0.0005 67 0.000478 200 0.00012 76 0.003525 84 0.00026 200 0.00002 rms value 0.54 g rms value 0.49 g rms value 0.64 g hour 21 h hour 21 h hour 21 h

[0149] The obtained test results are listed in Table 3.

[0150] Battery pack tray indentation deformation < 3mm The degree of chalking in the fiber-reinforced resin layer after ball impact Check for joint damage and bond delamination after vibration at 300,000 km mileage Example 1 1.3 R2 no Example 2 1.5 R1 no Example 3 1.8 R1 no Example 4 1.9 R1 no Example 5 2.4 R2 no Example 6 2.6 R2 no Example 7 2.4 R2 no Example 8 2.6 R2 no Example 9 2.2 R2 no Example 10 2.6 R2 no Example 11 2.8 R2 no Example 12 2 R4 no Example 13 2.8 R4 no Example 14 2.3 R4 no Example 15 2.9 R1 no Example 16 2.6 R4 no Example 17 2.8 R1 no Example 18 1.6 R4 no Example 19 1.4 R4 no Example 20 2.7 R4 no Comparative Example 1 3.6 R5 no Comparative Example 2 3.2 R5 no Comparative Example 3 2 R1 yes Comparative Example 4 3.2 R5 no Comparative Example 5 2.2 R5 no

[0151] As can be seen from the experimental results in Table 3, the thickness of the fiber-reinforced resin layer (d1), the thickness of the metal plate (d2), the elongation at break of the metal plate (ε2), the tensile strength of the metal plate (σ2), the elongation at break of the fiber-reinforced resin layer (ε0), and the tensile strength of the fiber-reinforced resin layer (σ0) are conditions

[0152]

[0153] If this is satisfied, a battery protection bottom plate with excellent impact resistance is obtained, which prevents the fiber-reinforced resin layer on the surface of the metal plate from falling off under long-term impact and improves corrosion resistance.

[0154] The foregoing description is merely a preferred embodiment of the present disclosure and is not intended to limit the present disclosure. All modifications, substitutions, improvements, etc. made within the spirit and principles of the present disclosure fall within the scope of protection of the present disclosure. Explanation of the symbols

[0155] Regarding the drawings: 1. Battery protection base 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 hole; 2. Cushioning layer; 3. Battery pack; 31. Tray; 4. Cushioning zone.

Claims

Claim 1 A battery protection bottom plate comprising a protective layer (11), a metal plate (12), and a fiber-reinforced resin layer (14), wherein the metal plate (12) is positioned between the protective layer (11) and the fiber-reinforced resin layer (14), and the metal plate (12) and the fiber-reinforced resin layer (14) are under the following conditions: Satisfies the following, wherein d1 is the thickness of the fiber-reinforced resin layer (14) in mm; d2 is the thickness of the metal plate (12) in mm; ε2 is the fracture elongation of the metal plate (12); σ2 is the tensile strength of the metal plate (12) in MPa; and ε0 is the fracture elongation of the fiber-reinforced resin layer (14); A battery protection bottom plate, wherein σ0 is the tensile strength of the fiber-reinforced resin layer (14) in MPa units, the thickness (d1) of the fiber-reinforced resin layer (14) is in the range of 0.5 mm to 2.1 mm, the thickness (d2) of the metal plate (12) is in the range of 0.6 mm to 1.2 mm, the elongation at break (ε2) of the metal plate (12) is in the range of 6% to 23%, the tensile strength (σ2) of the metal plate (12) is in the range of 560 MPa to 1180 MPa, the elongation at break (ε0) of the fiber-reinforced resin layer (14) is in the range of 2% to 9%, and the tensile strength (σ0) of the fiber-reinforced resin layer (14) is in the range of 200 MPa to 405 MPa. Claim 2 In claim 1, the metal plate (12) and the fiber-reinforced resin layer (14) are under the following conditions: A battery protection base plate satisfying [ ]. Claim 3 delete Claim 4 delete Claim 5 delete Claim 6 delete Claim 7 delete Claim 8 delete Claim 9 In claim 1, the material of the protective layer (11) is selected from fiber-reinforced resin material, resin coating, or electrophoretic coating, forming a battery protective bottom plate. Claim 10 A battery protection bottom plate according to claim 1, wherein the thickness of the protective layer (11) is in the range of 0.4 mm to 1.6 mm. Claim 11 A battery protection 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), the upper surface of the fiber-reinforced resin frame (13) is integrally connected with the protective layer (11), and the bottom surface of the fiber-reinforced resin frame (13) is integrally connected with the fiber-reinforced resin layer (14). Claim 12 In claim 11, a plurality of mounting holes (15) are spaced apart and formed on the inner edge of the battery protection bottom plate (1), and the mounting holes (15) sequentially penetrate the protection layer (11), the fiber-reinforced resin frame (13), and the fiber-reinforced resin layer (14), the battery protection bottom plate. Claim 13 In claim 11, 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, forming a battery protective bottom plate. Claim 14 A battery protection bottom plate according to claim 11, wherein the protective layer (11), the fiber-reinforced resin frame (13), and the fiber-reinforced resin layer (14) are glass fiber-reinforced resin members, and the glass fiber-reinforced resin member contains glass fibers in a content range of 60% to 70% by weight, and the glass fibers have an alkali content of less than 0.8% by weight. Claim 15 A battery protection bottom plate according to claim 11, wherein the protective layer (11) comprises a plurality of layers of first fiber-reinforced prepregs laminated together; and / or the fiber-reinforced resin frame (13) comprises a plurality of layers of second fiber-reinforced prepregs laminated together; and / or the fiber-reinforced resin layer (14) comprises a plurality of layers of third fiber-reinforced prepregs laminated together. Claim 16 A battery protection bottom plate according to claim 1, wherein the metal plate (12) is a steel plate, and a zinc plating layer, a zinc-plated iron alloy layer, or an electrophoretic paint protection layer is arranged on the outer surface of the steel plate. Claim 17 A battery pack composite protection structure comprising a battery protection bottom plate (1) and a battery pack (3) according to claim 1, wherein the battery protection bottom plate (1) is arranged below the battery pack (3) and a buffer zone (4) is provided between the battery pack (3) and the battery protection bottom plate (1). Claim 18 A battery pack composite protection structure according to claim 17, wherein the buffer zone (4) is filled with a buffer layer (2), and the buffer layer (2) is selected from a honeycomb material or a rigid foam material. Claim 19 A vehicle comprising a battery protection bottom plate (1) according to any one of claims 1, 2, 9 to 16 or a battery pack composite protection structure according to claim 17.

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