Composite material battery box and preparation method thereof

Abstract

The invention discloses a composite material battery box and a preparation method thereof, the composite material battery box comprises a box body, a cover plate, a first inner plate, a second inner plate and a water cooling structure, the box body is a rectangular inner cavity structure, and the box body and the cover plate are correspondingly buckled; the water cooling structure comprises a first water cooling pipe, a third water cooling pipe and a second water cooling pipe which are sequentially communicated, the first water cooling pipe and the second water cooling pipe are oppositely arranged on the inner walls of the two sides of the box body, the third water cooling pipe is arranged on the inner side face of the cover plate, the first inner plate is attached to the first water cooling pipe, and the second inner plate is attached to the second water cooling pipe; the box body, the cover plate, the two inner plates and the water cooling structure are all made of continuous glass fiber cloth reinforced thermoplastic prepreg. According to the invention, through reasonable composite material laying design and water cooling pipe structure design, and by utilizing the characteristics of high strength, low density, temperature resistance, impact resistance and the like of the continuous glass fiber cloth reinforced thermoplastic prepreg, the functional requirements of insulation, heat dissipation, fire prevention and the like of the lithium battery box are met.

Description

Technical Field

[0001] The present invention relates to the technical field of new energy electric vehicle parts, and in particular to a composite material battery box and a preparation method thereof. Background Art

[0002] As a composite material shell for lithium batteries, the battery pack is intended to apply composite materials to the core components of electric vehicles to effectively reduce the weight of the battery pack and increase the energy density, thereby increasing the driving range. For example, patents [ZL201720332832] a composite material battery shell structure for lithium batteries, [CN202020577103.5] a fireproof structure for automotive composite material battery boxes, [CN202011350222.8] a method for manufacturing a high-performance resin-based composite material battery box shell, the above composite materials are currently widely used in new energy electric vehicle lithium battery packs due to their many advantages such as light weight, high specific strength, corrosion resistance, and integrated molding. Patents such as [CN117429092A] a process for making a thermoplastic composite material battery pack shell, [CN117511064A] a composite material for a battery pack upper shell and its preparation method also show the preparation technology of thermoplastic composite materials on the battery pack shell, but the structure still requires the combination of a traditional aluminum water-cooled plate box and a composite material insulation box, which is more complicated in the assembly process and occupies a larger space. It can be seen that the existing battery box design is difficult to simultaneously meet the requirements of high strength, impact resistance, and light weight. It is necessary to propose a new material battery box to solve the shortcomings of the technology. Summary of the invention

[0003] The present invention aims to provide a composite material battery box and a preparation method thereof, which are used to solve the problem that the existing battery box design is difficult to simultaneously meet the requirements of high strength, impact resistance, light weight, etc.

[0004] In order to achieve the above technical purpose, the technical solution provided by the present invention is as follows: In the first aspect, the present invention provides a composite material battery box, comprising a box body, a cover plate, a first inner plate, a second inner plate and a water-cooling structure, the box body is a rectangular inner cavity structure, and the box body and the cover plate are correspondingly buckled; the water-cooling structure comprises a first water-cooling pipe, a third water-cooling pipe and a second water-cooling pipe which are connected and arranged in sequence, the first water-cooling pipe and the second water-cooling pipe are arranged oppositely on the inner walls of both sides of the box body, the third water-cooling pipe is arranged on the inner side of the cover plate, the first inner plate and the first water-cooling pipe are arranged in affixed relation, and the second inner plate and the second water-cooling pipe are arranged in affixed relation; the box body, the cover plate, the first inner plate, the second inner plate and the water-cooling structure are all made of continuous glass fiber cloth reinforced thermoplastic prepreg.

[0005] In a specific embodiment, a water inlet hole and a water outlet hole are provided on one side of the box body. The end of the first water cooling pipe away from the third water cooling pipe is connected to the external cooling water supply source through the water inlet hole, and the end of the second water cooling pipe away from the third water cooling pipe discharges cooling water through the water outlet hole.

[0006] In a specific embodiment, the first water-cooling pipe, the second water-cooling pipe and the third water-cooling pipe are all special-shaped pipe structures arranged in a winding manner.

[0007] Preferably, the continuous glass fiber cloth reinforced thermoplastic prepreg is prepared by a prepreg process of a reinforcing material and a matrix resin, wherein the reinforcing material includes any one or more of continuous glass fiber cloth and continuous unidirectional glass fiber cloth, and the matrix resin includes any one or more of prepregs prepared by a prepreg process such as polypropylene (PP), polyethylene (PE), polyphenylene sulfide (PPS), and polyetheretherketone (PEEK).

[0008] Preferably, the gap between the inner wall of the box body and the first inner plate, and the gap between the first water-cooling tube is filled with lightweight filling material; the gap between the inner wall of the box body and the second inner plate, and the gap between the second water-cooling tube is filled with lightweight filling material; the lightweight filling material includes any one or more of balsa wood, PVC foam, polyurethane foam, and PET foam.

[0009] In a second aspect, the present invention provides a method for preparing the composite material battery box as described above, comprising the following steps: (1) rolling a plurality of continuous glass fiber cloth reinforced thermoplastic prepregs on an air duct bag and expanding them by blowing air, and forming a hollow pipe structure after a first hot molding process to obtain a preform of a first water-cooling pipe, a second water-cooling pipe, and a third water-cooling pipe; (2) stacking a plurality of continuous glass fiber cloth reinforced thermoplastic prepregs to obtain a composite plate, and using the composite plate to assemble to form a preform of a box body, a cover plate, a first inner plate, and a second inner plate; (3) The preform of the second water-cooling tube is arranged inside the preform of the cover plate, and the preforms of the first water-cooling tube and the second water-cooling tube are arranged relatively on the inner walls of the preform of the box body on both sides, and the preforms of the first inner plate and the second inner plate are respectively attached to each other, and the preforms of the box body and the cover plate are respectively subjected to a second hot molding process, and a composite material battery box is obtained after cooling.

[0010] In a specific embodiment, during the expansion process, the open end of the air duct bag is connected to a pulse air source with a pulse pressure of 0.5MPa~1MPa. After pressurization for 3 minutes, the pressure is released and the preforms of the first water-cooling tube, the second water-cooling tube and the third water-cooling tube with special-shaped pipe structures are obtained respectively.

[0011] In a specific embodiment, the process conditions of the first hot pressing treatment are: the hot pressing temperature is 100° C. to 180° C., and the pressure is 10 MPa to 15 MPa.

[0012] In a specific embodiment, the specific steps of the second hot molding process include: placing the preforms of the box body and the cover plate into the preheating mold respectively, the mold preheating temperature is 100℃~180℃, and the pressure is 10MPa~15MPa. After preheating an appropriate amount of thermoplastic prepreg in another 180℃~250℃ heating box for 2~3 minutes, it is transferred to the press mold and filled into the joint of the preform, and molded, heat and pressurized for 2~5 minutes, and cooled after the hot pressing is completed.

[0013] In a specific embodiment, after cooling, the following steps are also included: the air duct bag is taken out of the cooled blank, and water inlet holes and water outlet holes are formed by cutting, grinding and drilling in sequence to obtain a composite material battery box; the battery pack is placed in the body of the composite material battery box, and the cover is fastened to seal it to obtain a packaged battery module.

[0014] Compared with the prior art, the beneficial effects of the present invention include: Firstly, the present invention realizes the functional requirements of insulation, heat dissipation, fire prevention and other aspects of the lithium battery box through reasonable composite material layer design and water cooling pipe structure design, and utilizes the high strength, low density, temperature resistance, impact resistance and other characteristics of continuous glass fiber cloth to reinforce thermoplastic prepreg; and the battery box made of the composite material is lighter and stronger than the steel battery box, has better heat resistance and better flame impact resistance than the aluminum battery box, and achieves the lightweight effect while meeting the strength, impact and other performance requirements.

[0015] Secondly, the composite material layer and the water-cooling tube structure layer are integrated through a hot mold forming process to obtain an integrated structure, realizing the integration of materials, structure and function. Compared with the traditional thermosetting composite material battery box, the present invention has a unique water-cooling structure, and the manufactured battery module or battery pack shell meets the needs of effective thermal management of lithium-ion batteries and battery systems with higher energy storage and energy density.

[0016] At the same time, the thermoplastic composite box is recyclable, and the thermoplastic composite hot molding technology provides a low-energy, environmentally friendly and efficient solution for the recycling of large composite automotive parts, which is of great significance to promoting the green and sustainable development of my country's automotive industry. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a perspective structural schematic diagram of an embodiment of a composite material battery box in the present invention; Figure 2 This is a schematic structural diagram of an embodiment of a composite material battery box in the present invention; In the figure: 1-box, 11-water inlet, 12-water outlet, 2-cover plate, 3-first inner plate, 4-second inner plate, 5-water cooling structure, 51-first water cooling pipe, 52-second water cooling pipe, 53-third water cooling pipe. DETAILED DESCRIPTION

[0018] In order to make the purpose, technical scheme and advantages of the present invention clearer, the present invention is further described in detail below in conjunction with embodiment.It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.The present invention is further described in detail below through specific embodiments.

[0019] See also Figure 1~2 , a composite material battery box provided in the first aspect of the present invention includes a box body 1, a cover plate 2, a first inner plate 3, a second inner plate 4 and a water-cooling structure 5, the box body 1 is a rectangular inner cavity structure, and the box body 1 and the cover plate 2 are correspondingly buckled; the water-cooling structure 5 includes a first water-cooling tube 51, a third water-cooling tube 53 and a second water-cooling tube 52 which are connected and arranged in sequence, the first water-cooling tube 51 and the second water-cooling tube 52 are relatively arranged on the inner walls of both sides of the box body 1, the third water-cooling tube 53 is arranged on the inner side of the cover plate 2, the first inner plate 3 is fitted with the first water-cooling tube 51, and the second inner plate 4 is fitted with the second water-cooling tube 52; the box body 1, the cover plate 2, the first inner plate, the second inner plate and the water-cooling structure 5 are all made of continuous glass fiber cloth reinforced thermoplastic prepreg. The present invention utilizes the high strength, low density, temperature resistance, impact resistance and other characteristics of continuous glass fiber cloth reinforced thermoplastic prepreg to achieve the functional requirements of lithium battery box insulation, heat dissipation, fire prevention and other aspects; and the battery box made of this composite material is lighter and stronger than a steel battery box, has better heat resistance than an aluminum battery box, and has better flame impact resistance, achieving a lightweight effect while meeting the strength, impact and other performance requirements.

[0020] In a specific embodiment, a water inlet hole 11 and a water outlet hole 12 are provided on one side of the box body 1. The end of the first water-cooling tube 51 away from the third water-cooling tube 53 is connected to the external cooling water supply source via the water inlet hole 11, and the end of the second water-cooling tube 52 away from the third water-cooling tube 53 discharges cooling water via the water outlet hole 12, so that the cooling water can realize a multi-directional cooling cycle through the first water-cooling tube 51, the third water-cooling tube 53 and the second water-cooling tube 52 in sequence.

[0021] In a specific embodiment, the first water-cooling tube 51, the second water-cooling tube 52 and the third water-cooling tube 53 are all special-shaped pipe structures arranged in a winding manner. During the specific setting process, they can be adaptively arranged according to the area of ​​the inner wall of the box body and the inner side of the cover body to make the pipes as full as possible to achieve a better cooling effect. The specific layout method and size can be adaptively set according to actual needs and are not limited here.

[0022] Preferably, the continuous glass fiber cloth reinforced thermoplastic prepreg is prepared by a prepreg process of reinforcing material and matrix resin, the reinforcing material includes any one or more of continuous glass fiber cloth and continuous unidirectional glass fiber cloth, and the matrix resin includes any one or more of polypropylene, polyethylene, polyphenylene sulfide, and polyetheretherketone. Preferably, the gap between the inner wall of the box 1 and the first inner plate 3, and the first water-cooling pipe 51 is filled with a lightweight filling material; the gap between the inner wall of the box 1 and the second inner plate 4, and the second water-cooling pipe 52 is filled with a lightweight filling material; the stability of the water-cooling pipe located in the interlayer can be improved by filling with lightweight filling materials, and at the same time, the mass will not increase too much. Among them, the lightweight filling material includes any one or more of balsa wood, PVC foam, polyurethane foam, and PET foam. Polyurethane foam is further preferred.

[0023] In a second aspect, the present invention provides a method for preparing the composite material battery box as described above, comprising the following steps: (1) A plurality of continuous glass fiber cloth reinforced thermoplastic prepregs are rolled on an air duct bag and expanded by blowing, and a hollow pipe structure is formed after a first hot molding process to obtain a preform of a first water-cooling pipe, a second water-cooling pipe, and a third water-cooling pipe. The stacking thickness of the continuous glass fiber cloth reinforced thermoplastic prepreg can be adaptively selected according to actual needs and is not limited here.

[0024] During the expansion process of step (1), the open end of the air duct bag is connected to a pulse air source with a pulse pressure of 0.5 MPa to 1 MPa. After 3 minutes, the pressure is released and the bag is taken out to obtain preforms of the first water-cooling tube, the second water-cooling tube and the third water-cooling tube with special-shaped pipe structures. The process conditions of the first hot pressing treatment are as follows: the hot pressing temperature is 100° C. to 180° C. and the pressure is 10 MPa to 15 MPa.

[0025] (2) Stacking a plurality of continuous glass fiber cloth reinforced thermoplastic prepregs to obtain a composite plate, and using the composite plate to assemble and form a preform of a box body, a cover plate, a first inner plate, and a second inner plate. The stacking thickness of the continuous glass fiber cloth reinforced thermoplastic prepreg can be adaptively selected according to actual needs and is not limited here.

[0026] (3) The preform of the second water-cooling tube is arranged inside the preform of the cover plate, and the preforms of the first water-cooling tube and the second water-cooling tube are arranged relatively on the inner walls of the preform of the box body on both sides, respectively attached to the first inner plate and the second inner plate, and the gap between the water-cooling tubes between the two inner plates and the inner wall of the box body is filled with lightweight filling material to improve its stability; the preforms of the box body and the cover plate are respectively subjected to a second hot molding process, and after cooling, a composite material battery box is obtained.

[0027] In step (3), the specific steps of the second hot molding treatment include: placing the preforms of the box body and the cover plate into preheating molds respectively, the mold preheating temperature is 100℃~180℃, the pressure is 10MPa~15MPa, preheating an appropriate amount of thermoplastic prepreg in another 180℃~250℃ heating box for 2~3 minutes, transferring it to the press mold and filling it into the joint of the preform, molding, keeping the temperature and pressure for 2~5 minutes, and cooling after the hot pressing is completed.

[0028] The composite material battery box of the present invention is molded by flexible thermoplastic prepreg, which is more convenient to produce and more efficient than traditional solutions, and has both thermoplastic and thermosetting process characteristics; the above-mentioned process prepreg and dry cloth have the same ductility, and during the pressing process, the glass fiber cloth can be shaped according to the shape of the mold, thereby realizing the forming of R angles and corners. The specific manufacturing method is two-time hot molding, the first hot molding is to prepare the composite water-cooling pipe preform, and the second hot molding is to prepare the composite material battery box. The process is simple, one-piece molding, and convenient for large-scale industrial application.

[0029] In addition, after cooling, the following steps are also included: the air duct bag is taken out of the cooled blank, and water inlet holes and outlet holes are formed by cutting, grinding and drilling in sequence to obtain a composite material battery box; the battery pack is placed in the body of the composite material battery box, and the cover is fastened to seal it to obtain a packaged battery module.

[0030] Example 1 The steps for preparing the composite ceramic product in this embodiment 1 are as follows: 1): A number of continuous glass fiber cloth reinforced polypropylene prepregs are rolled on the air duct bag and expanded by blowing. During the blowing and expansion process, the open end of the air duct bag is connected to a pulse air source with a pulse pressure of 0.7 MPa. After pressurization for 3 minutes, the bag is taken out by unloading the pressure and subjected to the first hot molding treatment at a temperature of 100°C and a pressure of 10 MPa. A hollow pipe structure is formed to obtain the preforms of the first water cooling pipe, the second water cooling pipe and the third water cooling pipe.

[0031] 2): A plurality of continuous glass fiber cloth reinforced thermoplastic prepregs are stacked to obtain a composite plate, and the composite plate is assembled to form a preform of a box body, a cover plate, a first inner plate, and a second inner plate.

[0032] 3): The preform of the second water-cooling tube is arranged inside the preform of the cover plate, and the preforms of the first water-cooling tube and the second water-cooling tube are arranged relatively on the inner walls of the preform on both sides of the box body, and the first inner plate and the second inner plate are respectively attached, and the preforms of the box body and the cover plate are subjected to a second hot molding treatment; the specific steps of the second hot molding treatment are: the preforms of the box body and the cover plate are respectively placed in the preheating mold, the mold preheating temperature is 100°C, and the pressure is 10MPa; after preheating an appropriate amount of thermoplastic prepreg in another 180°C heating box for 3 min, it is transferred to the press mold and filled into the joint of the preform, molded, kept warm and pressed for 5 min, and cooled after the hot pressing is completed; the cooled blank is taken out of the air duct bag, and is cut, polished and drilled in turn to form water inlet and outlet holes to obtain a composite material battery box.

[0033] 4): Place the battery pack into the composite material battery box, snap on the cover plate and seal it to obtain a packaged battery module.

[0034] Example 2 The difference from Example 1 is that the conditions for the first hot molding treatment in step 1) are: the hot molding temperature is 150°C and the pressure is 13 MPa; during the second hot molding treatment in step 3), the mold preheating temperature is 150°C and the pressure is 13 MPa, and an appropriate amount of thermoplastic prepreg is preheated in another 220°C heating box for 3 min.

[0035] Example 3 The difference from Example 1 is that the conditions for the first hot molding treatment in step 1) are: the hot molding temperature is 180°C and the pressure is 15 MPa; during the second hot molding treatment in step 3), the mold preheating temperature is 180°C and the pressure is 15 MPa, and an appropriate amount of thermoplastic prepreg is preheated in another 250°C heating box for 3 min.

[0036] Comparative Example 1 Comparative Example 1 uses a commonly used lithium battery box, which is an aluminum alloy box with an insulating layer coated on the outer surface of the box. The thickness of the aluminum alloy box is about 2-3 mm, and a water cooling plate is laid on the inner surface of the box. The thickness of the water cooling plate is 3-5 mm. Three groups of commonly used lithium battery boxes are selected for repeated testing.

[0037] The electrical insulation, overall weight, impact resistance, temperature resistance and other properties of Example 1 and Comparative Example 1 were tested, and the results are shown in Table 1. It can be seen that the composite material battery box prepared by the present invention, when used as a packaged battery module, has significantly improved electrical insulation and impact resistance, and the overall weight of the battery box is reduced by 22%.

[0038] Table 1

[0039] The specific implementation of the present invention described above does not constitute a limitation on the protection scope of the present invention. Any other corresponding changes and modifications made based on the technical concept of the present invention should be included in the protection scope of the claims of the present invention.

Claims

1. A composite material battery box, characterized in that: It includes a box body, a cover plate, a first inner plate, a second inner plate and a water cooling structure, wherein the box body is a rectangular inner cavity structure, and the box body and the cover plate are buckled correspondingly; The water cooling structure comprises a first water cooling pipe, a third water cooling pipe and a second water cooling pipe which are connected in sequence, the first water cooling pipe and the second water cooling pipe are arranged on the inner walls of both sides of the box body opposite to each other, the third water cooling pipe is arranged on the inner side of the cover plate, the first inner plate is fitted with the first water cooling pipe, and the second inner plate is fitted with the second water cooling pipe; The box body, the cover plate, the first inner plate, the second inner plate and the water cooling structure are all made of continuous glass fiber cloth reinforced thermoplastic prepreg.

2. The composite material battery box according to claim 1, characterized in that: A water inlet hole and a water outlet hole are formed on one side of the box body. The end of the first water cooling pipe away from the third water cooling pipe is connected to the external cooling water supply source via the water inlet hole, and the end of the second water cooling pipe away from the third water cooling pipe outputs cooling water via the water outlet hole.

3. The composite material battery box according to claim 1, characterized in that: The first water-cooling pipe, the second water-cooling pipe and the third water-cooling pipe are all special-shaped pipe structures arranged in a winding manner.

4. The composite material battery box according to claim 1, characterized in that: The continuous glass fiber cloth reinforced thermoplastic prepreg is prepared by prepregging a reinforcing material and a matrix resin, wherein the reinforcing material comprises any one or more of continuous glass fiber cloth and continuous unidirectional glass fiber cloth, and the matrix resin comprises any one or more of polypropylene, polyethylene, polyphenylene sulfide, and polyetheretherketone.

5. The composite material battery box according to claim 1, characterized in that: The gap between the inner wall of the box body and the first inner plate and the first water cooling tube is filled with a light filling material; The gap between the inner wall of the box body and the second inner plate and the second water-cooling tube is filled with a lightweight filling material; The lightweight filling material includes any one or more of balsa wood, PVC foam, polyurethane foam, and PET foam.

6. A method for preparing a composite material battery box according to any one of claims 1 to 5, characterized in that: The steps include: A plurality of continuous glass fiber cloth reinforced thermoplastic prepregs are rolled on an air duct bag and expanded by blowing, and a hollow pipe structure is formed after a first hot molding process, thereby obtaining a preform of a first water-cooling pipe, a second water-cooling pipe and a third water-cooling pipe; A plurality of continuous glass fiber cloth reinforced thermoplastic prepregs are stacked to obtain a composite plate, and the composite plate is assembled to form a preform of a box body, a cover plate, a first inner plate, and a second inner plate; The preform of the second water-cooling tube is arranged inside the preform of the cover plate, the preforms of the first water-cooling tube and the second water-cooling tube are arranged relatively on the inner walls on both sides of the preform of the box body, and the preforms of the first inner plate and the second inner plate are respectively attached, and the preforms of the box body and the cover plate are respectively subjected to a second hot molding treatment, and the composite material battery box is obtained after cooling.

7. The method for preparing a composite material battery box according to claim 5, characterized in that: During the blast expansion process, the open end of the air duct bag is connected to a pulse air source with a pulse pressure of 0.5MPa-1MPa. After pressurization for 3 minutes, the pressure is released and the preforms of the first water-cooling tube, the second water-cooling tube and the third water-cooling tube with special-shaped pipe structures are obtained respectively.

8. The method for preparing a composite material battery box according to claim 5, characterized in that: The process conditions of the first hot pressing treatment are: hot pressing temperature of 100° C. to 180° C. and pressure of 10 MPa to 15 MPa.

9. The method for preparing a composite material battery box according to claim 5, characterized in that: The specific steps of the second hot molding process include: The preforms of the box body and the cover plate are placed in preheating molds respectively, the mold preheating temperature is 100℃~180℃, and the pressure is 10MPa~15MPa; after preheating an appropriate amount of thermoplastic prepreg in another 180℃~250℃ heating box for 2~3min, it is transferred to the press mold and filled into the joint of the preform, and molded, kept warm and pressurized for 2~5min, and cooled after the hot pressing is completed.

10. The method for preparing a composite material battery box according to claim 9, characterized in that: After cooling, the following steps are also included: taking out the air duct bag from the cooled blank, cutting, grinding and drilling in sequence to form water inlet holes and water outlet holes to obtain the composite material battery box; The battery pack is placed in the body of the composite material battery box, and the cover is fastened to seal the box to obtain a packaged battery module.

Images