Battery pack box body, preparation process thereof, battery pack and vehicle

Abstract

The invention discloses a battery pack box and a preparation process thereof, a battery pack and a vehicle, and belongs to the technical field of vehicles. The battery pack box body provided by the invention is completely made of the composite material, the composite material comprises the resin material and the fiber material, the resin material is a base material and plays roles in fixing the fiber material and transferring energy, and the fiber material is a main bearing material and mainly plays a role in improving various mechanical properties of the box body. The battery pack box body prepared from the resin material and the fiber material through interaction not only has higher strength, but also has lighter weight.

Description

Technical Field

[0001] The present application relates to the field of vehicle technology, and in particular to a battery pack case and a preparation process thereof, a battery pack, and a vehicle. Background Art

[0002] As the power source of new energy vehicles, the battery pack plays an irreplaceable role. The battery pack includes the battery pack box and the cells and electrical components inside the box. To ensure the safety of the cells and electrical components inside the box, the battery pack box needs to have sufficient strength to prevent structural fractures or water leakage in the event of a collision.

[0003] The battery pack case in the related art is usually made of aluminum alloy or steel to provide sufficient strength, but the battery pack case made of such materials is heavy, which will affect the energy density of the battery pack. Therefore, how to provide a battery pack case with both high strength and light weight has become an urgent problem to be solved. Summary of the invention

[0004] The embodiment of the present application provides a battery pack box and its preparation process, a battery pack, and a vehicle, which have both high strength and light weight. The technical solution is as follows:

[0005] In one aspect, a battery pack box is provided, the battery pack box comprising: a box frame, a bottom guard plate and an upper shell;

[0006] The box frame, the bottom guard plate and the upper shell are all made of composite materials;

[0007] The composite material comprises a resin material and a fiber material, wherein the resin material comprises at least one of epoxy resin, phenolic resin, bismaleimide resin, benzoxazine resin, polycarbonate, polyamide, polyphenylene sulfide, polyetheretherketone, cyanate resin and polypropylene;

[0008] The fiber material includes at least one of glass fiber and carbon fiber.

[0009] In a possible implementation, the mass fraction of the resin material is 25% to 45%;

[0010] The mass fraction of the fiber material is 55% to 75%.

[0011] In another possible implementation, the glass fiber is more than two layers of continuous glass fiber.

[0012] In another possible implementation, the resin material is epoxy resin, and the fiber material is carbon fiber.

[0013] On the other hand, a preparation process of a battery pack case is provided, the preparation process comprising:

[0014] The composite material prepreg is made into a plurality of box beams by a pultrusion process;

[0015] Combining the plurality of box beams into a preliminary frame;

[0016] The prepreg is spread on the preliminary frame for preforming, and then placed in a frame mold for one-time hot pressing through a molding process to obtain the box frame;

[0017] The prepreg is respectively placed in a bottom guard plate mold and an upper shell mold, and hot-pressed in one step by a molding process to obtain the bottom guard plate and the upper shell respectively;

[0018] The box frame, the bottom guard plate and the upper shell are assembled into the battery pack box.

[0019] In a possible implementation, the pressure used in the molding process is 1090-1110 tons, and the curing temperature is 140° C.-150° C.

[0020] In another possible implementation, the surface density of the prepreg is 667±45 g / m 2 .

[0021] In another possible implementation, the density of the prepreg is less than or equal to 2.5 g / cm 3 .

[0022] On the other hand, a battery pack is provided, comprising the battery pack case described in any one of the above items.

[0023] On the other hand, a vehicle is provided, comprising the battery pack described above.

[0024] The embodiment of the present application provides a battery pack case, which is made entirely of composite materials, including resin materials and fiber materials, wherein the resin material is a matrix material, which plays a role in fixing the fiber material and transferring energy, and the fiber material is a main load-bearing material, which mainly plays a role in improving the mechanical properties of the case. The battery pack case prepared by the interaction of the resin material and the fiber material has both high strength and light weight.

[0025] It is to be understood that the foregoing general description and the following detailed description are exemplary only and are not restrictive of the present disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a schematic diagram of a battery pack box provided by the related technology;

[0027] Figure 2 It is an exploded view of a battery pack box provided by the related technology;

[0028] Figure 3 is an exploded view of a battery pack box provided in an embodiment of the present application;

[0029] Figure 4 It is a flow chart of a battery pack box preparation process provided in an embodiment of the present application;

[0030] Figure 5 It is a schematic diagram of a preliminary framework provided by an embodiment of the present application;

[0031] Figure 6 It is a schematic diagram of the overall structure of a battery pack box provided in an embodiment of the present application;

[0032] Figure 7 It is a schematic diagram of a battery pack case prepared by a molding process provided in an embodiment of the present application. DETAILED DESCRIPTION

[0033] In order to make the technical solutions and advantages of the present application clearer, the implementation methods of the present application are described in further detail below.

[0034] See also Figure 1 and Figure 2 , Figure 1 is a schematic diagram of a battery pack box in the related art, Figure 2 An exploded view of a battery pack box in the related art. Figure 2 The battery pack box includes an aluminum alloy profile frame 201 and a high-strength steel bottom guard plate 202. However, the welding process of this type of battery pack box is complicated, requiring precision welding and processing technology, with many and long welds, a long process cycle, and high costs. In addition, as new energy vehicles increase their demand for energy density and short-time charging, lightweighting of traditional metal boxes has become a challenge. Although aluminum alloys have better lightweight effects than steel, there are still some shortcomings. Furthermore, traditional metal boxes also need to be insulated, which will additionally increase production costs and manufacturing time.

[0035] The battery pack box provided in this application is made entirely of composite materials, which not only has good sealing performance and higher structural strength, but also does not require complex manufacturing processes, can improve overall reliability and production efficiency, and can significantly reduce the weight of the battery pack. This will be described in detail below.

[0036] The present application embodiment provides a battery pack box, see Figure 3 The battery pack box includes: a box frame 301, a bottom guard plate 302 and an upper shell (not shown in the figure);

[0037] The box frame 301, the bottom guard plate 302 and the upper shell are all made of composite materials;

[0038] The composite material includes a resin material and a fiber material, and the resin material includes at least one of epoxy resin, phenolic resin, bismaleimide resin, benzoxazine resin, polycarbonate, polyamide, polyphenylene sulfide, polyetheretherketone, cyanate resin and polypropylene;

[0039] The fiber material includes at least one of glass fiber and carbon fiber.

[0040] One thing that needs to be explained is that epoxy resin has good adhesion, mechanical properties and chemical corrosion resistance, and is the most widely used thermosetting resin. Phenolic resin has excellent heat resistance and flame retardancy. Bismaleimide resin has good heat resistance and mechanical properties. Benzoxazine resin is one of the common thermosetting resins, with high modulus, high strength, good heat resistance and other characteristics. Polycarbonate (PC), as a thermoplastic resin, has good toughness, impact resistance and fatigue resistance. Polyamide (PA), as a thermoplastic resin, is suitable for the matrix of continuous fiber reinforced thermoplastic polymer composites. Polyphenylene sulfide (PPS) and polyetheretherketone (PEEK) are both special engineering resins that can be used as the matrix of thermoplastic resin prepregs. Cyanate resin has high heat resistance.

[0041] In the embodiments of the present application, different resin materials can be selected according to different application needs and performance requirements to manufacture a composite material that meets specific performance requirements.

[0042] In a possible implementation manner, the resin material is epoxy resin, and the fiber material is carbon fiber.

[0043] In the embodiment of the present application, the battery pack case prepared by compounding carbon fiber and epoxy resin has both high strength and rigidity and light weight.

[0044] In a possible implementation, the mass fraction of the resin material is 25% to 45%;

[0045] The mass fraction of the fiber material is 55% to 75%.

[0046] In this implementation, the mass fraction of the resin material can be 25%, 30%, 35%, 40%, 45%, 50%, 55%, and the mass fraction of the fiber material can be 55%, 58%, 60%, 62%, 65%, 68%, 70%, 72%, 75%. Specifically, the mass fraction of the resin material is 45%, and the mass fraction of the fiber material is 55%.

[0047] In the embodiments of the present application, the resin material and the fiber material with different mass fractions are compounded, so that the resin material and the fiber material can interact better, which helps to improve the overall performance of the battery pack body.

[0048] In a possible implementation, the glass fibers are continuous glass fibers having more than two layers.

[0049] Correspondingly, the carbon fiber may also be continuous carbon fiber with more than 2 layers.

[0050] In the embodiment of the present application, compared with the traditional aluminum alloy profile box + high-strength steel bottom guard plate, the use of the above-mentioned continuous glass fiber and continuous carbon fiber as reinforcement materials for the battery pack box can reduce the weight of the battery pack box by 25%, and the number of parts can also be reduced by 10%, making the battery pack more lightweight and significantly improving the energy density of the battery pack.

[0051] In the embodiments of the present application, flame retardants, curing agents, initiators and color pastes may also be added to the composite material to adapt to different working conditions.

[0052] The flame retardant can be set and changed as needed, and is not specifically limited thereto. For example, the flame retardant is aluminum hydroxide.

[0053] The curing agent can also be set and changed as needed, and is not specifically limited to this. For example, the curing agent is rosin anhydride.

[0054] The initiator can also be set and changed as needed, and is not specifically limited to this. For example, the initiator is tert-butyl perbenzoate.

[0055] In addition, if flame retardants, curing agents, initiators and color pastes are added to the composite material, the mass fractions of the flame retardants, curing agents, initiators and color pastes can also be set and changed as needed, and there is no specific limitation on this.

[0056] The embodiment of the present application provides a battery pack case, which is made entirely of composite materials, including resin materials and fiber materials. The resin material is the matrix material, which plays the role of fixing the fiber material, transferring energy, and determining the appearance of the product. The fiber material is the main load-bearing material, which mainly plays the role of improving the mechanical properties of the case. The battery pack case prepared by the interaction of the resin material and the fiber material has both high strength and light weight.

[0057] The battery pack box provided in this application also has the following beneficial effects:

[0058] (1) The battery pack case prepared in the present application has the advantages of low density, high specific strength and specific modulus. Its specific strength is 4 to 5 times that of steel, 3 to 4 times that of aluminum alloy, and 2.5 to 3.5 times that of titanium alloy. Its specific modulus is 5.5 to 6 times that of steel, aluminum alloy, and titanium alloy. Therefore, under the condition of the same strength and stiffness, the weight of the battery pack case prepared by the composite material provided in the present application can be greatly reduced, which is incomparable to any existing metal material in terms of saving energy and improving the performance of components.

[0059] (2) The battery pack case prepared in the present application has high fatigue strength and good damage safety characteristics. Usually, when a composite material is subjected to static load or fatigue load, damage first occurs at the weakest point, such as transverse cracks, interface debonding, delamination, fiber breakage, etc. Then the numerous fibers and interfaces will prevent or delay the expansion of the cracks, and the matrix will quickly redistribute the load and transfer it to the unbroken fibers through the interface, so that the entire component can continue to bear the load and will not immediately break as a whole. In addition, the composite material provided in the present application has very slow crack expansion during the fatigue process, and will not break rapidly until about 90% of the fatigue life, and there are obvious signs before the overall fracture, so the damage safety characteristics are good. However, traditional aluminum alloy cases or other metal cases are often suddenly damaged without obvious signs under fatigue loads.

[0060] (3) The battery pack case prepared in the present application also has excellent vibration reduction performance. The natural frequency of a general structure is not only related to the shape of the structure itself, but also proportional to the square root of the specific modulus of the material. The composite material used in the present application has a high specific modulus and therefore also has a high natural frequency. The high natural frequency is not easy to cause resonance during operation, which can avoid early damage caused by resonance. At the same time, the interface between the resin material and the fiber material in the composite material has vibration absorption capabilities, so the vibration damping is very high. A vibration test was conducted on aluminum alloy beams of the same shape and size. The aluminum alloy beam took 9 seconds to stop vibrating, while the beam made of the composite material provided in the present application only took 2 to 5 seconds to stop vibrating.

[0061] (4) The composite material used in this application has good anisotropy and designability of material properties, which are outstanding features of composite materials, especially high-performance composite materials. The formula design and layer design of the composite material can be carried out according to the load distribution and use conditions of the engineering structure, so as to reasonably and effectively exert the role and potential performance of each component material, meet the predetermined requirements of material properties, realize the optimized design of components, and achieve safety, reliability, and economic rationality.

[0062] (5) The battery pack box prepared in the present application has excellent chemical stability and better corrosion resistance than traditional metal boxes. It also has good electromagnetic wave transmittance and heat resistance, and can maintain good structural integrity after a fire test.

[0063] (6) The composite material used in the present application is an electrically non-repellent material with excellent electrical insulation properties. Therefore, the prepared battery pack box does not require additional insulation treatment, which can further simplify the production process and reduce production costs.

[0064] The present application also provides a method for preparing a battery pack case. Figure 4 , the preparation process comprises:

[0065] Step 401: a plurality of box beams are formed from composite material prepreg by pultrusion process.

[0066] For each box beam, the prepreg of the composite material is subjected to processes such as extrusion molding, heating and curing, and fixed-length cutting under external force traction through a pultrusion process to form the box beam.

[0067] The box beam may be a cross beam, a side beam or other beams of the box body, which is not specifically limited. In addition, the prepreg is a resin material impregnated with a fiber material to form a composition of the resin material and the fiber material.

[0068] In one possible implementation, the surface density of the prepreg is 667±45 g / m 2 .

[0069] Specifically, the surface density of the prepreg can be 622g / m 2 , 630g / m 2 , 640g / m 2 , 650g / m 2 , 660g / m 2 , 667g / m 2 , 670g / m 2 , 680g / m 2 , 690g / m 2 , 700g / m 2 , 710g / m 2 , 712g / m 2 .

[0070] In the embodiment of the present application, the use of the prepreg with the above-mentioned surface density can enable the resin material and the fiber material to interact better, so that the battery pack body has both high strength and light weight.

[0071] In a possible implementation, the density of the prepreg can be adjusted by changing the type of resin material.

[0072] The density of the prepreg is less than or equal to 2.5 g / cm 3 Specifically, the density of the prepreg can be 2.5 g / cm 3 , 2.4g / cm3 , 2.3g / cm 3 , 2.2g / cm 3 , 2.1g / cm 3 , 2.0g / cm 3 , 1.9g / cm 3 , 1.5g / cm 3 , 1.2g / cm 3 , 1.0g / cm 3 .

[0073] In the embodiments of the present application, adjusting the density of the prepreg has the following advantages:

[0074] ① Improve material properties: By adjusting the density of the prepreg, the ratio of resin material and fiber material can be optimized, thereby improving the mechanical properties of the composite material, such as strength, hardness, impact resistance, etc. This is because the content of resin material in the prepreg directly affects the mechanical properties of the composite material. Appropriate density can ensure a good combination of resin material and fiber material and improve the overall performance of the composite material.

[0075] ② Reduce structural load: Low-density composite materials can reduce the weight of the battery pack body, effectively improving the designability and lightweight level of the battery pack, which is crucial to improving the performance and market competitiveness of the battery pack body.

[0076] ③ Improve overall performance: Adjusting the density of prepreg helps to improve the overall performance of composite materials, including heat resistance, corrosion resistance and electrical insulation performance.

[0077] ④ Improve process efficiency: Adjusting the density of the prepreg can improve the efficiency of the placement process, so that less resin flows out of the prepreg during the molding process, resulting in a battery pack body with higher mechanical properties and dimensional accuracy.

[0078] ⑤ Reduce costs: By adjusting the density of prepreg, the resin waste during the curing and molding process can be reduced, thereby reducing costs and improving material utilization.

[0079] ⑥Optimize the interface bonding strength: Adjusting the density of the prepreg can optimize the interface bonding strength between the fiber material and the resin material. The higher the interface bonding strength, the better the mechanical properties and heat resistance of the composite material.

[0080] In summary, adjusting the density of prepreg is of great significance in improving the performance of composite materials, reducing structural loads, improving process efficiency and reducing costs.

[0081] Step 402: Assemble a plurality of box beams into a preliminary frame.

[0082] In the embodiment of the present application, a plurality of box beams may be assembled into a preliminary frame by gluing, or by other methods, which is not specifically limited.

[0083] See also Figure 5 , Figure 5 A schematic diagram of a preliminary framework provided for an embodiment of the present application.

[0084] Step 403: Spread the prepreg on the preliminary frame for preforming, and then put it into the frame mold for one-time hot pressing through a molding process to obtain a box frame.

[0085] In this step, the prepreg is first made into sheets and then cut. The cut prepreg sheets are spread on the preliminary frame for preforming, and then placed in the frame mold and hot-pressed in one step through a molding process to obtain a box frame.

[0086] Among them, laser processing can be used during the hot pressing process to make the size of the box frame meet the requirements.

[0087] The pressure used in the molding process is 1090-1110 tons, and the curing temperature is 140°C-150°C.

[0088] Among them, the pressure used in the molding process can be 1090 tons, 1091 tons, 1092 tons, 1093 tons, 1094 tons, 1095 tons, 1096 tons, 1097 tons, 1098 tons, 1099 tons, 1100 tons, 1101 tons, 1102 tons, 1103 tons, 1104 tons, 1105 tons, 1106 tons, 1107 tons, 1108 tons, 1109 tons, and 1110 tons.

[0089] The curing temperature may be 140°C, 141°C, 142°C, 143°C, 144°C, 145°C, 146°C, 147°C, 148°C, 149°C, 150°C.

[0090] In an embodiment of the present application, the prepreg and the preliminary frame are hot-pressed and formed at one time using the above-mentioned pressure and curing temperature, thereby obtaining a box frame with higher strength and lighter weight.

[0091] See also Figure 6 The box frame includes side beams 601, cross beams 602, battery pack mounting points 603, electrical connection ports 604 and electrical integration points 605. The side beams 601, cross beams 602, battery pack mounting points 603, electrical connection ports 604 and electrical integration points 605 are integrally formed through a molding process.

[0092] Step 404: Place the prepreg into the bottom guard plate mold and the upper shell mold respectively and perform one-time hot pressing molding through a molding process to obtain the bottom guard plate and the upper shell respectively.

[0093] In this step, the prepreg is placed in the bottom guard plate mold, and is hot-pressed in one step through a molding process to obtain the bottom guard plate; the prepreg is placed in the upper shell mold, and is hot-pressed in one step through the molding process to obtain the upper shell.

[0094] The pressure and curing temperature used in the molding process in step 404 may be the same as or different from the pressure and curing temperature used in the molding process in step 403 , and this is not specifically limited.

[0095] One point that needs to be explained is that when preparing the battery pack case, the case frame can be prepared first through steps 401 to 403, and then the bottom guard plate and the upper shell can be prepared through step 404; or the bottom guard plate and the upper shell can be prepared first through step 404, and then the case frame can be prepared through steps 401 to 403. There is no specific limitation on the order of preparation.

[0096] Step 405: Assemble the box frame, bottom guard plate and upper shell into a battery pack box.

[0097] In the embodiment of the present application, the box frame, the bottom guard plate and the upper shell can be assembled into a battery pack box by bolts, or the box frame, the bottom guard plate and the upper shell can be assembled into a battery pack box by other methods, without specific limitation.

[0098] See also Figure 7 , Figure 7 It is a schematic diagram of a battery pack case prepared by a molding process provided in an embodiment of the present application.

[0099] One thing that needs to be explained is that there are some reports in the relevant technology of using composite materials to prepare bottom guard plates, upper shells or box frames, but they are basically prepared through simple thermoplastic processes. Although they are lighter in weight, their strength is not comparable to that of traditional aluminum alloys, let alone the strength of this application.

[0100] The preparation process of the battery pack case provided in the embodiment of the present application is to form a box beam through a prepreg and a pultrusion process, and then form a box frame through a one-time hot pressing molding through a molding process. Compared with composite materials made by traditional thermoplastic processes, it has higher product consistency and higher structural strength. Compared with traditional aluminum alloy cases or other metal cases, it does not require complex precision welding and processing technology, which greatly simplifies the production process.

[0101] On the other hand, an embodiment of the present application provides a battery pack, which includes the battery pack case introduced above.

[0102] In the embodiment of the present application, the battery pack may also include battery cells, electrical components and other devices, which are not specifically limited.

[0103] On the other hand, an embodiment of the present application provides a vehicle, which includes the battery pack introduced above.

[0104] The technical solution of the present application will be described in detail below through specific embodiments.

[0105] In the following specific examples, operations involved without specifying conditions were performed under conventional conditions or conditions recommended by the manufacturer.

[0106] Example 1

[0107] The present embodiment provides a battery pack case, wherein the resin material used in the battery pack case is polyetheretherketone (PEEK), and the fiber material is carbon fiber (AS4).

[0108] The mass fraction of polyetheretherketone (PEEK) is 45%, and the mass fraction of carbon fiber (AS4) is 55%.

[0109] Example 2

[0110] This embodiment provides a battery pack case, in which the resin material used is epoxy resin (EPOXY) and the fiber material is carbon fiber (IM6).

[0111] The mass fraction of the epoxy resin (EPOXY) is 45%, and the mass fraction of the carbon fiber (IM6) is 55%.

[0112] Example 3

[0113] This embodiment provides a battery pack case, in which the resin material used is polypropylene (PP) and the fiber material is glass fiber.

[0114] The mass fraction of polypropylene (PP) is 45%, and the mass fraction of glass fiber is 55%.

[0115] Comparative Example 1

[0116] This comparative example provides a battery pack case, and the material used for the battery pack case is steel.

[0117] Comparative Example 2

[0118] This comparative example provides a battery pack case, and the material used for the battery pack case is aluminum alloy.

[0119] Comparative Example 3

[0120] This comparative example provides a battery pack case, and the material used for the battery pack case is titanium alloy.

[0121] The present application tests the battery pack cases provided by Examples 1 to 3 and Comparative Examples 1 to 3, and the test results are shown in Table 1 below.

[0122] Table 1

[0123] Example / Comparative Example <![CDATA[Specific strength (MPa / (kg·m -3 ))]]> <![CDATA[Specific stiffness (MPa / (kg·m -3 ))]]> Comparative Example 1 0.25 27 Comparative Example 2 0.2 26 Comparative Example 3 0.2 25 Example 1 1.4 84 Example 2 2.2 128 Example 3 0.8 53

[0124] Among them, the specific strength is the ratio of the strength of the battery pack box to its density. The higher the specific strength, the lighter the battery pack box. The specific stiffness is the ratio of the elastic modulus of the battery pack box to its density. The higher the specific stiffness, the greater the rigidity of the battery pack box.

[0125] It can be seen from Table 1 that the specific strength and specific stiffness of the battery pack boxes provided by Examples 1 to 3 are higher than those of Comparative Examples 1 to 3. This shows that the battery pack box prepared by the composite material in the present application can provide greater strength and stiffness, while also having a lighter weight.

[0126] Moreover, the battery pack box provided by Example 2 has the highest specific strength and specific stiffness, and the resin material used in Example 2 is epoxy resin and the fiber material is carbon fiber. This shows that compared with other resin materials and fiber materials, the battery pack box prepared by the epoxy resin and carbon fiber compound has greater strength and stiffness, and is also lighter.

[0127] The above description is only for the purpose of facilitating those skilled in the art to understand the technical solution of the present application and is not intended to limit the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A battery pack box, characterized in that: The battery pack box includes: a box frame, a bottom guard plate and an upper shell; The box frame, the bottom guard plate and the upper shell are all made of composite materials; The composite material comprises a resin material and a fiber material, wherein the resin material comprises at least one of epoxy resin, phenolic resin, bismaleimide resin, benzoxazine resin, polycarbonate, polyamide, polyphenylene sulfide, polyetheretherketone, cyanate resin and polypropylene; The fiber material includes at least one of glass fiber and carbon fiber.

2. The battery pack case according to claim 1, characterized in that: The mass fraction of the resin material is 25% to 45%; The mass fraction of the fiber material is 55% to 75%.

3. The battery pack case according to claim 1, characterized in that: The glass fibers are continuous glass fibers having more than two layers.

4. The battery pack case according to claim 1, characterized in that: The resin material is epoxy resin, and the fiber material is carbon fiber.

5. A process for preparing a battery pack box according to any one of claims 1 to 4, characterized in that: The preparation process comprises: The composite material prepreg is made into a plurality of box beams by a pultrusion process; Combining the plurality of box beams into a preliminary frame; The prepreg is spread on the preliminary frame for preforming, and then placed in a frame mold for one-time hot pressing through a molding process to obtain the box frame; The prepreg is respectively placed in a bottom guard plate mold and an upper shell mold, and hot-pressed in one step by a molding process to obtain the bottom guard plate and the upper shell respectively; The box frame, the bottom guard plate and the upper shell are assembled into the battery pack box.

6. The preparation process according to claim 5, characterized in that: The pressure used in the molding process is 1090-1110 tons, and the curing temperature is 140°C-150°C.

7. The preparation process according to claim 5, characterized in that: The surface density of the prepreg is 667±45g / m 2 .

8. The preparation process according to claim 5, characterized in that: The density of the prepreg is less than or equal to 2.5 g / cm 3 .

9. A battery pack, characterized in that: The battery pack comprises the battery pack case according to any one of claims 1 to 4.

10. A vehicle, characterized in that: The vehicle includes the battery pack according to claim 9.

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