A battery protection bottom plate and a battery pack composite protection structure, and a vehicle

Abstract

In order to overcome the problem of insufficient corrosion resistance of the existing battery pack bottom protection plate due to the detachment of the surface PVC layer under impact, the present invention provides a battery protection bottom plate, including a protection layer, a metal plate and a fiber reinforced resin layer, wherein 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 meet the following conditions: At the same time, the present invention also discloses a battery pack composite protection structure and a vehicle including the above-mentioned battery protection bottom plate. The battery protection bottom plate provided by the present invention has excellent impact resistance and corrosion resistance.

Description

Technical Field

[0001] The present invention belongs to the technical field of vehicle batteries, and in particular relates to a battery protection bottom plate and a battery pack composite protection structure, and a vehicle. Background Art

[0002] With the rapid development of electric vehicles, people have higher and higher safety requirements for electric vehicles. As the power source of electric vehicles, the safety of power battery packs is of great importance. In electric vehicles, the battery pack is generally located at the bottom of the vehicle chassis and connected to the chassis by bolts. The lower surface of the battery pack is exposed. During the daily driving of the vehicle, the bottom of the battery pack is easy to bump, resulting in the failure of the box body to break and the protection. During the driving process, the splashing of stones at the bottom will also cause impact on the battery pack. In order to cope with complex working conditions, a protective plate is usually provided at the bottom of the battery pack to protect the bottom of the battery pack. The protective plate is usually a steel plate, and the bottom surface of the protective plate is sprayed with a PVC layer to play an impact and corrosion resistance role. However, the overall impact resistance of the existing protective plate still needs to be improved. Specifically, under the impact of external hard objects, the PVC layer on the bottom of the protective plate is easy to powderize, thereby falling off from the surface of the protective plate, thereby exposing the steel plate inside, affecting the corrosion resistance of the protective plate. Summary of the invention

[0003] In view of the problem that the surface PVC layer of the existing battery pack bottom protection plate falls off due to impact, resulting in insufficient corrosion resistance, the present invention provides a battery protection bottom plate and a battery pack composite protection structure and a vehicle.

[0004] The technical solution adopted by the present invention to solve the above technical problems is as follows:

[0005] In one aspect, the present invention provides a battery protection bottom plate, comprising a protective layer, a metal plate and a fiber-reinforced resin layer, wherein the metal plate is located between the protective layer and the fiber-reinforced resin layer, and the metal plate and the fiber-reinforced resin layer meet the following conditions:

[0006]

[0007] Wherein, d1 is the thickness of the fiber-reinforced resin layer, in mm;

[0008] d2 is the thickness of the metal plate, in mm;

[0009] ε2 is the fracture elongation of the metal plate;

[0010] σ2 is the tensile strength of the metal plate, in MPa;

[0011] ε0 is the elongation at break of the fiber-reinforced resin layer;

[0012] σ0 is the tensile strength of the fiber reinforced resin layer, in MPa.

[0013] Optionally, the metal plate and the fiber-reinforced resin layer meet the following conditions:

[0014]

[0015] Optionally, the thickness d1 of the fiber reinforced resin layer is 0.6-2.0 mm.

[0016] Optionally, the thickness d2 of the metal plate is 0.7-1.6 mm.

[0017] Optionally, the elongation at break ε2 of the metal plate is 5% to 20%.

[0018] Optionally, the tensile strength σ2 of the metal plate is 590 to 1180 MPa.

[0019] Optionally, the elongation at break ε0 of the fiber reinforced resin layer is 2.5% to 8%.

[0020] Optionally, the tensile strength σ0 of the fiber reinforced resin layer is 240-380 MPa.

[0021] Optionally, the material of the protective layer is selected from fiber-reinforced resin material, resin coating or electrophoretic coating.

[0022] Optionally, the thickness of the protective layer is 0.4-1.6 mm.

[0023] Optionally, the battery protection bottom plate also includes a fiber reinforced resin frame, the metal plate and the fiber reinforced resin frame are located between the protective layer and the fiber reinforced resin layer, 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.

[0024] Optionally, a plurality of mounting holes are spaced apart on the inner side of the edge of the battery protection bottom plate, and the mounting holes sequentially pass through the protection layer, the fiber reinforced resin frame and the fiber reinforced resin layer.

[0025] Optionally, 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 part, a glass fiber-reinforced polypropylene resin part, a glass fiber-reinforced polyethylene resin part, a glass fiber-reinforced polycarbonate resin part or a glass fiber-reinforced polystyrene resin part.

[0026] Optionally, the protective layer, the fiber-reinforced resin frame and the fiber-reinforced resin layer are all glass fiber-reinforced resin parts, the glass fiber-reinforced resin parts contain 60% to 70% of glass fibers, and the alkali content of the glass fibers is less than 0.8%.

[0027] Optionally, the protective layer comprises a plurality of first fiber-reinforced prepregs stacked on top of each other;

[0028] The fiber-reinforced resin frame includes multiple layers of second fiber-reinforced prepreg laminated on each other;

[0029] The fiber-reinforced resin layer includes a plurality of third fiber-reinforced prepregs stacked one on another.

[0030] Optionally, the metal plate is a steel plate, and a galvanized layer, a galvanized iron alloy layer or an electrophoretic paint protective layer is provided on the outer surface of the steel plate.

[0031] On the other hand, the present invention provides a battery pack composite protection structure, including a battery pack and the battery protection bottom plate as described above, wherein 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.

[0032] Optionally, the buffer zone is filled with a buffer layer, and the buffer layer is selected from a honeycomb material or a hard foam material.

[0033] On the other hand, the present invention provides a vehicle comprising the battery protection floor or the battery pack composite protection structure as described above.

[0034] According to the battery protection bottom plate provided by the present invention, a fiber-reinforced resin layer is compounded on the surface of the metal plate. The fiber-reinforced resin layer serves as the bottom surface covering structure of the metal plate, which can avoid direct contact between the metal plate and the air and external moisture, and play an anti-corrosion protection role for the metal plate. At the same time, the fiber-reinforced resin also has good mechanical strength, which effectively improves the stiffness and strength of the metal plate, making it have higher impact resistance.

[0035] Furthermore, the inventors found that when the fiber-reinforced resin layer and the metal plate are matched, some matching groups can obtain a battery protection bottom plate with excellent impact resistance, while some matching groups have surface damage of the fiber-reinforced resin layer. Further experiments have found that the tensile strength and elongation at break of the selected fiber-reinforced resin layer must have a certain corresponding relationship with the tensile strength and elongation at break of the metal plate, so that when the battery protection bottom plate is impacted by external energy, the adhesion between the fiber-reinforced resin layer and the metal plate can be ensured without being damaged. Combined with the thickness of the fiber-reinforced resin layer and the metal plate, the relationship is summarized: When the thickness d1 of the fiber reinforced resin layer, the thickness d2 of the metal plate, the elongation at break ε2 of the metal plate, the elongation at break 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 meet the above conditions, it is beneficial to obtain a battery protective base plate with excellent impact resistance and corrosion resistance. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 It is a structural schematic diagram of the battery protection bottom plate provided by the present invention;

[0037] Figure 2 Schematic diagram of the structure of different first fiber reinforced prepreg unidirectional tapes in the protective layer provided by the present invention;

[0038] Figure 3 It is a schematic diagram of the structure of different first fiber woven cloth reinforced prepregs in the protective layer provided by the present invention;

[0039] Figure 4 It is a structural schematic diagram of the battery pack composite protection structure provided by the present invention;

[0040] Figure 5 yes Figure 4 The enlarged schematic diagram of point A in the middle;

[0041] Figure 6 is a bottom cross-sectional schematic diagram of a battery pack composite protection structure provided by an embodiment of the present invention;

[0042] Figure 7 is a bottom cross-sectional schematic diagram of a battery pack composite protection structure provided by another embodiment of the present invention;

[0043] Figure 8 It is a schematic bottom cross-sectional view of a battery pack composite protective structure provided by another embodiment of the present invention.

[0044] The reference numerals in the drawings of the specification are as follows:

[0045] 1. Battery protection base plate; 11. Protection layer; 111. First fiber reinforced prepreg unidirectional tape; 112. First fiber woven cloth reinforced prepreg; 12. Metal plate; 13. Fiber reinforced resin frame; 14. Fiber reinforced resin layer; 15. Mounting hole; 2. Buffer layer; 3. Battery pack; 31. Tray; 4. Buffer zone. DETAILED DESCRIPTION

[0046] In order to make the technical problems, technical solutions and beneficial effects solved by the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0047] In the description of the present invention, it should be understood that the terms "upper", "lower", "top", "bottom", "inner", "outer", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In the description of the present invention, unless otherwise specified, "plurality" means two or more.

[0048] See also Figure 1 As shown, an embodiment of the present invention provides a battery protection bottom plate 1, comprising a protection layer 11, a metal plate 12 and a fiber reinforced resin layer 14, wherein the metal plate 12 is located between the protection layer and the fiber reinforced resin layer 14, and the metal plate 12 and the fiber reinforced resin layer 14 meet the following conditions:

[0049]

[0050] Wherein, d1 is the thickness of the fiber-reinforced resin layer 14, in mm;

[0051] d2 is the thickness of the metal plate 12, in mm;

[0052] ε2 is the fracture elongation of the metal plate 12;

[0053] σ2 is the tensile strength of the metal plate 12, in MPa;

[0054] ε0 is the elongation at break of the fiber-reinforced resin layer 14;

[0055] σ0 is the tensile strength of the fiber-reinforced resin layer 14 , and its unit is MPa.

[0056] The fiber-reinforced resin layer 14 serves as the bottom cladding structure of the metal plate 12, which can prevent the metal plate 12 from direct contact with air and external moisture, and play an anti-corrosion protection role for the metal plate 12. At the same time, the fiber-reinforced resin also has good mechanical strength, which effectively improves the rigidity and strength of the metal plate 12, making it have higher impact resistance.

[0057] Furthermore, the inventors found that when the fiber-reinforced resin layer 14 and the metal plate 12 are matched, some matching groups can obtain a battery protection bottom plate 1 with excellent impact resistance, while some matching groups have surface damage of the fiber-reinforced resin layer 14. Further experiments have found that the tensile strength and elongation at break of the selected fiber-reinforced resin layer 14 must have a certain corresponding relationship with the tensile strength and elongation at break of the metal plate 12, so that when the battery protection bottom plate 1 is impacted by external energy, the adhesion between the fiber-reinforced resin layer 14 and the metal plate 12 can be ensured without being damaged. Combined with the thickness of the fiber-reinforced resin layer 14 and the metal plate 12, the relationship is summarized: When the thickness d1 of the fiber reinforced resin layer 14, the thickness d2 of the metal plate 12, the elongation at break ε2 of the metal plate 12, the elongation at break 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 meet the above conditions, it is beneficial to obtain a battery protective base plate 1 with excellent impact resistance and corrosion resistance.

[0058] In some embodiments, the metal plate 12 and the fiber-reinforced resin layer 14 meet the following conditions:

[0059] 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 comprehensively considered, which is beneficial to the shedding of the surface fiber-reinforced resin layer 14 when subjected to external impact, thereby ensuring the corrosion resistance of the battery protection bottom plate 1 and extending its service life.

[0060] In some embodiments, the fiber reinforced resin layer 14 has a thickness d1 of 0.6-2.0 mm.

[0061] 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.

[0062] The thickness d1 of the fiber-reinforced resin layer 14 is related to the metal plate 12's resistance to external air and water vapor corrosion, and also affects its bonding strength with the metal plate 12 and the overall strength after being composited with the metal plate 12. When the thickness d1 of the fiber-reinforced resin layer 14 is within the above range, it can avoid falling off the surface of the metal plate 12 under high-energy impact, and can effectively maintain the anti-corrosion and strength enhancement effects on the metal plate 12.

[0063] In some embodiments, the thickness d2 of the metal plate 12 is 0.7-1.6 mm.

[0064] 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.

[0065] 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, as the thickness of the metal plate 12 increases, its protection strength gradually increases, but its material cost also gradually increases, and the distance from the bottom of the vehicle to the ground 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 guaranteed, the cost can be effectively controlled, the distance from the ground can be guaranteed, and the lightweight control of the vehicle is also facilitated.

[0066] In some embodiments, the elongation at break ε2 of the metal plate 12 is 5% to 20%.

[0067] Specifically, the elongation at break 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%.

[0068] In some embodiments, the tensile strength σ2 of the metal plate 12 is 590-1180 MPa.

[0069] Specifically, the tensile strength σ2 of the metal plate 1212 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.

[0070] The tensile strength σ2 and elongation at break ε2 of the metal plate 12 can be tested by GB / T 228.1-2010 Metal Material Tensile Test Part 1: Room Temperature Test Scheme. As the main protective component of the battery protection bottom plate 1, the metal plate 12 faces complex impact conditions. Its tensile strength σ2, as a strength index of the metal plate 12, affects the deformation resistance of the metal plate 12 within its elastic deformation range. When the tensile strength σ2 is higher, the metal plate 12 can resist higher impacts without irreversible deformation; and the elongation at break ε2 affects the ability of the metal plate 12 to resist rupture after deformation. When the elongation at break ε2 is higher, the metal plate 12 can resist higher impacts without cracking. However, under normal circumstances, the higher the tensile strength σ2 of the metal plate 12, the lower its 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 taken into account, thereby ensuring the impact strength and anti-cracking performance of the metal plate 12.

[0071] In some embodiments, the elongation at break ε0 of the fiber-reinforced resin layer 14 is 2.5% to 8%.

[0072] Specifically, the elongation at break ε0 of the fiber reinforced resin layer 14 can 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%.

[0073] In some embodiments, the tensile strength σ0 of the fiber-reinforced resin layer 14 is 240-380 MPa.

[0074] 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.

[0075] The elongation at break ε0 of the fiber-reinforced resin layer 14 and the tensile strength σ0 of the fiber-reinforced resin layer 14 can be tested by the GB / T 1447-2005 fiber-reinforced plastic tensile performance test method. Type I specimens are suitable for fiber-reinforced thermoplastic sheets, and samples are made and tested according to the type I specimens specified in the national standard. When impacted, the fiber-reinforced resin layer 14 is the surface layer of the battery protection bottom plate 1 that directly contacts the impact object. The increase in tensile strength σ0 is conducive to improving the deformation resistance of the fiber-reinforced resin layer 14; the increase in tensile strength σ0 will lead to a decrease in the elongation at break ε0, while affecting the adhesion of the fiber-reinforced resin layer 14 to the metal plate 12, resulting in delamination under 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 delamination or falling off.

[0076] In actual application, in order to improve the impact resistance of the battery pack 3 and prevent the fiber-reinforced resin layer from powdering and falling off, the above six parameters are interrelated and inseparable. For example, when the tensile strength σ2 of the metal plate 12 and the tensile strength σ0 of the fiber-reinforced resin layer 14 cannot be well matched, it is easy to cause vibration asynchrony, and thus it is more likely to cause delamination. When the elongation at break ε2 of the metal plate 12 and the elongation at break ε0 of the fiber-reinforced resin layer 14 cannot be well matched, it is easy to cause the fiber-reinforced resin layer 14 to powder under impact. And the metal plate 1 2 is associated with the tensile strength σ2 of the metal plate 12 and the elongation at break ε2, and the tensile strength σ0 of the fiber-reinforced resin layer 14 is associated with the tensile strength σ0 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 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 this will correspondingly lead to an increase in the total mass and total thickness of the battery protection bottom plate 1, which is not conducive to the lightweight requirements and cost control of the vehicle, and also leads to a reduction in the distance of the vehicle from the ground. Therefore, through the relationship Taking into account the influence of various factors on the protection performance of the battery pack 3, it is beneficial to improve the impact resistance of the battery protection bottom plate 1 and avoid the problems of delamination and surface powdering due to impact.

[0077] In some embodiments, the material of the protective layer 11 is selected from fiber-reinforced resin materials, resin coatings or electrophoretic coatings. The protective layer 11 is used to improve the corrosion resistance and composite strength of the metal plate 12.

[0078] In some embodiments, the thickness of the protective layer 11 is 0.4 to 1.6 mm. Specifically, the thickness of the protective layer 11 can 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 its performance in resisting water vapor penetration and its bonding strength with the metal plate 12. When the thickness of the protective layer 11 is within the above range, it can effectively improve the protective performance of the metal plate 12 and improve the bonding strength with the metal plate 12.

[0079] In some embodiments, the battery protection bottom plate 1 also 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, 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.

[0080] A fiber reinforced resin frame 13 is arranged on the periphery of the metal plate 12 as a transition piece for connecting the frame position of the protective layer 11 and the fiber reinforced resin layer 14, which can effectively offset 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, ensure the frame position strength of the battery protection base plate 1, and further facilitate to use the frame position of the battery protection base plate 1 as its installation structure on the battery, thereby improving its impact resistance.

[0081] like Figure 4 As shown, in some embodiments, a plurality of mounting holes 15 are spaced apart on the inner side of the edge of the battery protection base plate 1 , and the mounting holes 15 pass through the protection layer 11 , the fiber reinforced resin frame 13 and the fiber reinforced resin layer 14 in sequence.

[0082] The mounting hole 15 is used for mounting and fastening the battery protection bottom plate 1 at the bottom of the battery pack 3. By arranging the mounting hole 15 on the inner side of the edge of the battery protection bottom plate 1 and sequentially passing through the protection layer 11, the fiber reinforced resin frame 13 and the fiber reinforced resin layer 14, it is possible to avoid the mounting hole 15 passing through the metal plate 12, thereby avoiding corrosion problems caused by the metal plate 12 being exposed at the mounting hole 15. At the same time, the fiber reinforced resin frame 13 is conducive to improving the overall thickness and tensile shear strength of the mounting position, and has sufficient installation stability.

[0083] The plurality of mounting holes 15 are disposed around the outer circumference of the metal plate 12 to evenly disperse the top gravity and the bottom impact force on the metal plate 12 .

[0084] Specifically, during installation, a connecting piece is arranged to pass through the installation hole 15 to fix the battery protection bottom plate 1 to the bottom of the battery pack 3, and the connecting piece is a rivet, a screw or a bolt.

[0085] In different embodiments, the resins of the protective layer 11, the fiber-reinforced resin frame 13 and the fiber-reinforced resin layer 14 are independently selected from thermosetting and / or thermoplastic materials. Examples may include, but are not limited to, epoxy resins, phenolic plastics, phenols, cyanates, imides (e.g., polyimide, bismaleimide (BMI), polyetherimide), polypropylenes, polyesters, benzoxazines, polybenzimidazoles, polybenzothiazoles, polyamides, polyamide-imides, polysulfones, polyethersulfones, polycarbonates, polyethylene terephthalate and polyetherketones (e.g., polyetherketone (PEK), polyetheretherketone (PEEK), polyetherketoneketone (PEKK), etc.) and combinations thereof.

[0086] In different embodiments, the fibers of the protective layer 11, the fiber-reinforced resin frame 13 and the fiber-reinforced resin layer 14 are independently selected from glass fibers, aramid fibers, carbon fibers, graphite fibers, boron fibers, aromatic polyamide fibers and mixtures thereof.

[0087] 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, chopped fibers, non-woven fabrics, unidirectional reinforced fiber substrates, woven fabrics, and the like.

[0088] In a preferred embodiment, the protective layer 11, the fiber reinforced resin frame 13 and the fiber reinforced resin layer 14 are each independently selected from glass fiber reinforced polyamide resin parts or glass fiber reinforced polypropylene resin parts, glass fiber reinforced polyethylene resin parts, glass fiber reinforced polycarbonate resin parts or glass fiber reinforced polystyrene resin parts.

[0089] In a more preferred embodiment, the protective layer 11, the fiber reinforced resin frame 13 and the fiber reinforced resin layer 14 are made of the same resin material. The same resin material can ensure the affinity of the materials between different layers, thereby ensuring the degree of integration between different layers and improving the overall strength.

[0090] In some embodiments, the protective layer 11, the fiber reinforced resin frame 13 and the fiber reinforced resin layer 14 are all glass fiber reinforced resin parts, and the glass fiber reinforced resin parts contain 60% to 70% glass fiber, which is beneficial to improving the material strength of the protective layer 11, the fiber reinforced resin frame 13 and the fiber reinforced resin layer 14.

[0091] In some embodiments, the glass fibers have an alkali content of <0.8%.

[0092] When the alkali content of the glass fiber is lower than 0.8%, it is beneficial to improve the anti-aging performance of the protective layer 11, the fiber-reinforced resin frame 13 and the fiber-reinforced resin layer 14, and slow down the performance degradation of the materials after long-term use.

[0093] In a preferred embodiment, the glass fiber is selected from E glass fiber or S glass fiber.

[0094] In some embodiments, the protective layer 11 includes multiple layers of first fiber-reinforced prepreg laminated on each other;

[0095] The fiber-reinforced resin frame 13 includes multiple layers of second fiber-reinforced prepreg laminated on each other;

[0096] The fiber-reinforced resin layer 14 includes a plurality of third fiber-reinforced prepregs stacked one on another.

[0097] like Figure 2 As shown, in one embodiment, the protective layer 11 includes multiple layers of mutually stacked first fiber reinforced prepreg unidirectional tapes 111, the fiber arrangement direction of two adjacent layers of the first fiber reinforced prepreg unidirectional tapes 111 is approximately 90° staggered, and the allowable deviation range of the ply angle of two adjacent layers of the first fiber reinforced prepreg unidirectional tapes 111 is ±20°.

[0098] The fibers in the first fiber reinforced prepreg unidirectional tape 111 are arranged unidirectionally. When subjected to a tensile force along the fiber extension direction, the fibers in the first fiber reinforced prepreg unidirectional tape 111 can effectively bear the tensile force. By arranging the fibers of adjacent first fiber reinforced prepreg unidirectional tapes 111 in an approximately 90° staggered manner, it is beneficial to improve the uniformity of force on the protective layer 11 in all directions.

[0099] The fiber reinforced resin frame 13 includes multiple layers of second fiber reinforced prepreg unidirectional tapes stacked on each other, the fibers in the second fiber reinforced prepreg unidirectional tapes are arranged unidirectionally, the fiber arrangement directions of two adjacent layers of the second fiber reinforced prepreg unidirectional tapes are staggered at approximately 90°, and the allowable deviation range of the ply angle of two adjacent layers of the second fiber reinforced prepreg unidirectional tapes is ±20°.

[0100] The fiber-reinforced resin layer 14 includes multiple layers of third fiber-reinforced prepreg unidirectional tapes stacked on each other, the fibers in the third fiber-reinforced prepreg unidirectional tapes are arranged unidirectionally, the fiber arrangement directions of two adjacent layers of the third fiber-reinforced prepreg unidirectional tapes are staggered at approximately 90°, and the allowable deviation range of the ply angle of two adjacent layers of the third fiber-reinforced prepreg unidirectional tapes is ±20°.

[0101] 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 will not be described in detail.

[0102] like Figure 3 As shown, in another embodiment, the protective layer 11 includes multiple layers of first fiber woven cloth reinforced prepreg 112 stacked on each other, and the fibers in the first fiber woven cloth reinforced prepreg 112 form a woven cloth in a staggered form.

[0103] The fiber reinforced resin frame 13 includes a plurality of second fiber woven cloth reinforced prepregs stacked on each other, wherein the fibers in the second fiber woven cloth reinforced prepregs are woven in an interlaced manner.

[0104] The fiber-reinforced resin layer 14 includes a plurality of mutually stacked third fiber woven cloth reinforced prepregs, wherein the fibers in the third fiber woven cloth reinforced prepregs are woven in an interlaced manner.

[0105] 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.

[0106] In one embodiment, the metal plate 12 is a steel plate, and the outer surface of the steel plate is provided with a galvanized layer, a galvanized iron alloy layer or an electrophoretic paint protective layer.

[0107] Compared with other metal materials, the steel plate used as the metal plate 12 has better tensile strength and elongation, can meet the impact resistance requirements, and is beneficial to improving the protection of the battery pack 3.

[0108] 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 anti-corrosion performance of the steel plate. When the protective layer 11 or the fiber-reinforced resin layer 14 is damaged, the galvanic cell effect formed by the galvanized layer or the galvanized iron alloy layer and the steel plate causes the galvanized layer or the galvanized iron alloy layer to corrode before the steel plate, thereby protecting the steel plate. The electrophoretic paint protective layer has good adhesion and can effectively isolate the steel plate from the external environment.

[0109] like Figure 3 As shown, another embodiment of the present invention provides a battery pack composite protection structure, including a battery pack 3 and the battery protection bottom plate 1 as described above, wherein 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.

[0110] Since the battery pack composite protection structure adopts the above-mentioned battery protection bottom plate 1, the protection strength of the battery protection bottom plate 1 is effectively guaranteed while ensuring a relatively low overall thickness, and the structure has good corrosion resistance.

[0111] In some embodiments, the battery pack 3 includes a tray 31 and batteries disposed on the tray 31 .

[0112] In different embodiments, the buffer zone 4 may be disposed between the battery pack 3 and the battery protection base plate 1 in different ways.

[0113] like Figure 5 As shown, in one embodiment, a groove is provided inwardly on the bottom surface of the tray 31 to form the buffer zone 4 , and the battery protection bottom plate 1 is in the shape of a flat plate, and the battery protection bottom plate 1 covers the buffer zone 4 .

[0114] like Figure 6 As shown, in one embodiment, the frame position of the battery protection base plate 1 is connected to the bottom surface of the tray 31, and a groove is provided inwardly on the bottom surface of the tray 31. The battery protection base plate 1 protrudes away from the tray 31 to form the buffer zone 4 between the tray 31 and the battery protection base plate 1.

[0115] like Figure 7 As shown, in one embodiment, the frame position of the battery protection base plate 1 is connected to the bottom surface of the tray 31, the bottom surface of the tray 31 is a plane, and the battery protection base plate 1 protrudes away from the tray 31 to form the buffer zone 4 between the tray 31 and the battery protection base plate 1.

[0116] 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 hard foam material.

[0117] Honeycomb material or hard foam material can absorb the collapse deformation space of the battery protection plate under the action of strong external impact, buffer and absorb part of the energy of the strong external impact, prevent the compression deformation of the battery protection bottom plate 1 from impacting the internal battery cells of the battery pack 3, and further protect the battery pack 3.

[0118] In a preferred embodiment, the honeycomb material is selected from PP honeycomb material or aluminum honeycomb material; the rigid foam material is selected from PU rigid foam material, PET rigid foam material, PMI rigid foam material, PVC rigid foam material, PET rigid foam material, MPP rigid foam material, PLA rigid foam material, PI rigid foam material or EPTU foam material.

[0119] Another embodiment of the present invention provides a vehicle, comprising the battery protection floor or the battery pack composite protection structure as described above.

[0120] The present invention is further described below by way of examples.

[0121] Table 1

[0122]

[0123] Example 1

[0124] This embodiment is used to illustrate the composite protective structure of a battery pack disclosed in the present invention, including a battery pack, a buffer layer and a battery protective bottom plate, the battery protective bottom plate including 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 a fiber reinforced resin material, the metal plate is located between the protective layer and the fiber reinforced resin layer, and the fiber reinforced resin layer is located below the metal plate, 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 arranged below the battery pack, a buffer zone is formed between the battery pack and the battery protective bottom plate, the buffer zone is filled with the buffer layer, and the frame of the battery protective bottom plate is installed at the bottom frame position of the battery pack by rivets.

[0125] Among them, 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%, 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] Embodiments 2 to 20

[0127] Examples 2 to 20 are used to illustrate the composite protection structure of the battery pack disclosed in the present invention, including most of the structures in Example 1, and the difference is that:

[0128] The metal plates and fiber-reinforced resin layers provided in Examples 2 to 20 in Table 1 were used.

[0129] Comparative Examples 1 to 5

[0130] Comparative Examples 1 to 5 are used to compare and illustrate the composite protection structure of the battery pack disclosed in the present invention, including most of the structures in Example 1, and the differences are:

[0131] The metal plates and fiber-reinforced resin layers provided in Comparative Examples 1 to 5 in Table 1 were used.

[0132] Performance Testing

[0133] The following performance tests were performed on the composite protection structures of the battery packs provided in the above embodiments and comparative examples:

[0134] 1. Use a sphere as an impact head to impact the battery protection bottom plate of the battery pack composite protection structure to simulate the working condition where the bottom of the vehicle is hit by a foreign object. The diameter of the sphere is 25 mm, the weight is 10 kg, the impact energy is 300 J, and the impact speed is 8.5 m / s. The center point of the battery protection bottom plate and four points around the center point are selected as impact points, and five impacts are performed.

[0135] Measure the dent deformation of the battery tray at each impact point, select the impact point with the largest dent deformation, and record it as the dent deformation of the battery tray. Generally, the dent deformation of a 300J energy impact is required to be no more than 3mm.

[0136] Use a vernier caliper to measure the diameter of the powdered area of ​​the battery protection bottom plate after impact. Repeat the measurement three times for a single impact point to determine the average value. Select the impact point with the largest powdered area diameter and record it as the powdered diameter of the fiber resin layer. The powdering degree grading standards are as follows:

[0137] R1: The diameter of the fiber resin layer powder is less than 2mm, and the metal plate is not exposed;

[0138] R2: The fiber resin layer powdering diameter is less than 5mm, and the metal plate is not exposed;

[0139] R3: The diameter of the fiber resin layer powder is less than 8mm, and the metal plate is not exposed;

[0140] R4: The diameter of the fiber resin layer powder is less than 10mm, and the metal plate is not exposed;

[0141] R5: The powdering area of ​​the fiber resin layer is >10mm, and the metal plate is exposed.

[0142] 2. Install the battery pack composite protection structure on a vibration table and perform 30W mileage simulated vibration to check whether the connection is damaged after vibration and whether the battery protection bottom plate is delaminated.

[0143] 30w mileage simulated vibration test: According to the requirements of GB / T 2423.43, the test object is installed on the vibration table, and the torque of each installation point is tested and recorded. The vibration test is carried out in three directions. The test process refers to GB / T 2423.56. The specific test conditions are as follows:

[0144] First, random vibration was applied in the Z direction for 21 h (random vibration conditions are shown in Table 2), and then fixed frequency vibration was applied in the Z direction for 1 h (fixed frequency vibration conditions: 24 Hz fixed frequency, 1 g fixed frequency amplitude);

[0145] Secondly, random vibration was applied in the Y direction for 21 h (the random vibration conditions are shown in Table 2), and then fixed frequency vibration was applied in the Y direction for 1 h (fixed frequency vibration conditions: 24 Hz fixed frequency, 1 g fixed frequency amplitude);

[0146] Furthermore, random vibration was applied in the X direction for 21 h (the random vibration conditions are shown in Table 2), and then fixed-frequency vibration was applied in the X direction for 1 h (the fixed-frequency vibration conditions were: 24 Hz fixed-frequency frequency, 1 g fixed-frequency amplitude).

[0147] Among them, PSD stands for power spectral density, which represents the power spectral density of vibration at a certain frequency; the rms value represents the comprehensive acceleration of vibration and feedbacks the vibration intensity.

[0148] Table 2 Random vibration test

[0149]

[0150] The test results obtained are entered in Table 3.

[0151] Table 3

[0152]

[0153] From the test results in Table 3, it can be seen that when 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 meet the conditions It is beneficial to obtain a battery protection bottom plate with excellent impact resistance, which can prevent the fiber-reinforced resin layer on the surface of the metal plate from falling off under long-term impact conditions and improve its corrosion resistance.

[0154] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A battery protection base plate, characterized in that: The invention comprises a protective layer, a metal plate and a fiber-reinforced resin layer, wherein the metal plate is located between the protective layer and the fiber-reinforced resin layer, the tensile strength σ0 of the fiber-reinforced resin layer is 240-380 MPa, the thickness d1 of the fiber-reinforced resin layer is 0.6-2.0 mm, the thickness d2 of the metal plate is 0.7-1.6 mm, the elongation at break ε2 of the metal plate is 5%-20%, the tensile strength σ2 of the metal plate is 590-1180 MPa, the elongation at break ε0 of the fiber-reinforced resin layer is 2.5%-8%, and the metal plate and the fiber-reinforced resin layer meet the following conditions: Wherein, d1 is the thickness of the fiber-reinforced resin layer, in mm; d2 is the thickness of the metal plate, in mm; ε2 is the fracture elongation of the metal plate; σ2 is the tensile strength of the metal plate, in MPa; ε0 is the elongation at break of the fiber-reinforced resin layer; σ0 is the tensile strength of the fiber reinforced resin layer, in MPa.

2. The battery protection bottom plate according to claim 1, characterized in that: The metal plate and the fiber-reinforced resin layer meet the following conditions: 。 3. The battery protection bottom plate according to claim 1, characterized in that: The material of the protective layer is selected from fiber-reinforced resin material, resin coating or electrophoretic coating.

4. The battery protection bottom plate according to claim 1, characterized in that: The thickness of the protective layer is 0.4-1.6 mm.

5. The battery protection bottom plate according to claim 1, characterized in that: The battery protection bottom plate also includes a fiber reinforced resin frame, the metal plate and the fiber reinforced resin frame are located between the protective layer and the fiber reinforced resin layer, 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.

6. The battery protection bottom plate according to claim 1, characterized in that: A plurality of mounting holes are spaced apart on the inner side of the edge of the battery protection bottom plate, and the mounting holes sequentially pass through the protection layer, the fiber reinforced resin frame and the fiber reinforced resin layer.

7. The battery protection bottom plate according to claim 1, characterized in that: The protective layer, the fiber-reinforced resin frame and the fiber-reinforced resin layer are each independently selected from glass fiber-reinforced polyamide resin parts, glass fiber-reinforced polypropylene resin parts, glass fiber-reinforced polyethylene resin parts, glass fiber-reinforced polycarbonate resin parts or glass fiber-reinforced polystyrene resin parts.

8. The battery protection bottom plate according to claim 1, characterized in that: The protective layer, the fiber-reinforced resin frame and the fiber-reinforced resin layer are all glass fiber-reinforced resin parts. The glass fiber-reinforced resin parts contain 60% to 70% of glass fibers, and the alkali content of the glass fibers is less than 0.8%.

9. The battery protection bottom plate according to claim 1, characterized in that: The protective layer comprises a plurality of first fiber-reinforced prepregs stacked on top of each other; The fiber-reinforced resin frame includes multiple layers of second fiber-reinforced prepreg laminated on each other; The fiber-reinforced resin layer includes a plurality of third fiber-reinforced prepregs stacked one on another.

10. The battery protection bottom plate according to claim 1, characterized in that: The metal plate is a steel plate, and a zinc-plated layer, a galvanized iron alloy layer or an electrophoretic paint protective layer is arranged on the outer surface of the steel plate.

11. A battery pack composite protection structure, characterized in that: It comprises a battery pack and a battery protection base plate as described in any one of claims 1 to 10, wherein 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.

12. The battery pack composite protection structure according to claim 11, characterized in that: The buffer zone is filled with a buffer layer, and the buffer layer is selected from honeycomb material or hard foam material.

13. A vehicle, characterized in that: It includes the battery protection bottom plate as described in any one of claims 1 to 10, or includes the battery pack composite protection structure as described in claim 11 or 12.

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