A carbon fiber composite fuel tank and its preparation method

Abstract

This application relates to the technical field of carbon fiber composite material preparation, in particular to a carbon fiber composite fuel tank and a preparation method thereof. A carbon fiber composite fuel tank includes a first fuel tank assembly and a second fuel tank assembly. The first fuel tank assembly is fixedly connected to the second fuel tank assembly by hot pressing to form a complete carbon fiber composite fuel tank. The first fuel tank assembly includes a first rectangular shell, and a first connecting plate is fixedly connected to the periphery of the first rectangular shell. The bottom surface of the first connecting plate is flush with the bottom surface of the first rectangular shell. The second fuel tank assembly includes a second fuel tank shell, and a second connecting plate member is integrally formed on the second fuel tank shell. The first connecting plate and the second connecting plate member are fixed by hot pressing. The preparation process of this application is relatively simple, and the produced carbon fiber composite fuel tank is not only light in texture, but also has good mechanical strength and oil resistance, and does not leak oil under a pressure of 0.2 MPa.

Description

Technical Field

[0001] This application relates to the technical field of carbon fiber composite material preparation, and in particular to a carbon fiber composite fuel tank and a preparation method thereof. Background Art

[0002] At present, the commercially available fuel tank materials are mainly divided into metal materials and plastic materials. Among them, the processing methods of metal material fuel tanks include sand mold casting method, machining and welding method, etc. The machining and welding method is to produce two half-structured fuel tanks by a molding method, and then weld the half-structured fuel tanks together to obtain a finished metal fuel tank. However, whether it is the sand mold casting method or the machining and welding method, the production process is relatively complex, and the metal fuel tank is relatively heavy in quality and vulnerable to corrosion, and is gradually being phased out by the market.

[0003] The processing methods of plastic material fuel tanks include blow molding method, extrusion molding method, molding and then electromagnetic welding method, etc. The blow molding method is limited by the process, and the wall thickness of the produced fuel tank is relatively thin. For fuel tanks with relatively thick wall thickness requirements, the processing difficulty is large and the production cost is high. The production processes of the extrusion molding method and the molding and then electromagnetic welding method are relatively complex, and the mechanical properties and weather resistance of the produced plastic fuel tanks are relatively low, and the service life is short.

[0004] In view of the above related technologies, this application proposes a carbon fiber composite fuel tank and a preparation method thereof. Summary of the Invention

[0005] In order to solve the problems existing in the related technologies, this application provides a carbon fiber composite fuel tank and a preparation method thereof.

[0006] In a first aspect, a carbon fiber composite fuel tank provided by this application is achieved through the following technical solutions:

[0007] A carbon fiber composite fuel tank includes a first fuel tank component and a second fuel tank component. The first fuel tank component is fixedly connected to the second fuel tank component by hot pressing to form a complete carbon fiber composite fuel tank. The first fuel tank component includes a first rectangular shell, and a first connecting plate is fixedly connected to the periphery of the first rectangular shell. The bottom surface of the first connecting plate is flush with the bottom surface of the first rectangular shell. The second fuel tank component includes a second fuel tank shell, and a second connecting plate member is integrally formed on the second fuel tank shell. The first connecting plate and the second connecting plate member are fixed by hot pressing.

[0008] The preparation process of this application is relatively simple, and the produced carbon fiber composite fuel tank is not only light in texture, but also has good mechanical strength and oil resistance, and does not leak oil under a pressure of 0.2 MPa. In addition, this application uses the method of fixing the first connecting plate and the second connecting plate member by hot pressing, which can not only reduce the production difficulty of this application, but also ensure the oil resistance and pressure resistance of this application.

[0009] Preferably, a rectangular convex shell is integrally formed on one end side of the upper surface of the first rectangular shell; a first connection hole and a second connection hole are formed through the upper and lower surfaces of the rectangular convex shell; the second fuel tank shell includes a second shell and a special-shaped curved surface shell, and the special-shaped curved surface shell is integrally formed on the second shell; an installation groove is integrally formed on the side wall of the second shell facing away from the special-shaped curved surface shell; one end of the installation groove is open through the upper surface of the second shell; an oil filling port and a detector preform are integrally formed on the upper surface of the second shell; the oil filling port and the detector preform are respectively located on both sides of the opening of the installation groove.

[0010] By adopting the above technical solution, the quality of the carbon fiber composite fuel tank produced by the present application can be guaranteed and meet the actual needs of customers.

[0011] Preferably, the internal carbon fiber tissue layer structure formed by the first fuel tank assembly and the second fuel tank assembly is the same; taking the first fuel tank assembly as an example, the first fuel tank assembly includes an upper layer warp knitted resin-impregnated carbon fiber cloth, a lower layer warp knitted resin-impregnated carbon fiber cloth, a 0° resin-impregnated carbon fiber cloth, and a 90° resin-impregnated carbon fiber cloth; the 0° resin-impregnated carbon fiber cloth is integrally formed between the upper layer warp knitted resin-impregnated carbon fiber cloth and the lower layer warp knitted resin-impregnated carbon fiber cloth; the 90° resin-impregnated carbon fiber cloth is integrally formed between the upper layer warp knitted resin-impregnated carbon fiber cloth and the lower layer warp knitted resin-impregnated carbon fiber cloth.

[0012] By adopting the above technical solution, the mechanical strength, weather resistance, and corrosion resistance of the present application can be guaranteed and the quality of the present application can be effectively reduced, and a carbon fiber composite fuel tank with light weight and excellent mechanical strength, weather resistance, and corrosion resistance can be produced.

[0013] Preferably, the first fuel tank assembly includes a single upper layer warp knitted resin-impregnated carbon fiber cloth, a single lower layer warp knitted resin-impregnated carbon fiber cloth, four 0° resin-impregnated carbon fiber cloths, and a single 90° resin-impregnated carbon fiber cloth. Two stacked 0° resin-impregnated carbon fiber cloths are integrally formed between the upper layer warp knitted resin-impregnated carbon fiber cloth and the adjacent 90° resin-impregnated carbon fiber cloth; two stacked 0° resin-impregnated carbon fiber cloths are integrally formed between the lower layer warp knitted resin-impregnated carbon fiber cloth and the adjacent 90° resin-impregnated carbon fiber cloth.

[0014] By adopting the above technical solution, the mechanical strength of the present application is further improved, and a carbon fiber composite fuel tank with light weight and excellent mechanical strength, weather resistance, and corrosion resistance can be produced.

[0015] In the second aspect, a preparation method of a carbon fiber composite fuel tank provided by the present application is realized through the following technical solutions:

[0016] A preparation method of a carbon fiber composite fuel tank includes the following steps:

[0017] Step 1: Prepare the first fuel tank assembly using a special mold for the first fuel tank assembly, and at the same time prepare the second fuel tank assembly using a special mold for the second fuel tank assembly;

[0018] Step 2: Demold and deburr to obtain the first fuel tank assembly and the second fuel tank assembly;

[0019] Step 3: Coat the lower surface of the first connecting plate with an epoxy resin composition, cure it into a gel state for standby, and at the same time coat the lower surface of the second connecting plate with an epoxy resin composition, cure it into a gel state for standby;

[0020] Step 4: Thermally press the surface of the first connecting plate coated with the epoxy resin composition and the surface of the second connecting plate coated with the epoxy resin composition, and cool to obtain the finished carbon fiber composite fuel tank.

[0021] The preparation process of the present application is relatively simple and convenient for achieving the purpose of batch production. Through the preparation method of the present application, a carbon fiber composite fuel tank with light weight, excellent mechanical strength, weather resistance, and corrosion resistance can be obtained by equipment.

[0022] Preferably, the special mold for the first fuel tank assembly includes a first bottom template, a second template, a third template, a fourth template, and a first forming mold. The first forming mold has the same structure as the first fuel tank assembly but different dimensions; the first forming mold is arranged in the cavity formed by assembling the first bottom template, the second template, the third template, and the fourth template, and there is a gap between the first forming mold and the cavity, so that the outer wall of the first forming mold abuts against the first fuel tank assembly to be thermally pressed;

[0023] The first bottom template is provided with a first air inlet channel; two mutually spaced first limiting die grooves are provided on the surface of the first bottom template; a first air inlet communicating the first air inlet channel and the first limiting die groove is provided on the surface of the first bottom template; the first bottom template is detachably connected to the second template;

[0024] The second template is provided with two first through grooves penetrating the upper and lower surfaces; a first positioning convex block is formed on the surface of the second template; the first positioning convex block is integrally formed with a second communication groove having the same specification as the first through groove; a chamfered convex is integrally formed on the surface of the first positioning convex block; when laying the first fuel tank assembly to be thermally pressed, the bottom surface of the first forming mold can abut against the first positioning convex block, and the first forming mold can abut against the chamfered convex;

[0025] The third template is detachably connected to the second template; a bottom fitting groove is formed on the surface of the third template facing the second template; the first positioning bump is fitted into the bottom fitting groove; two third communication grooves are formed through the third template; the first forming die can pass through the third communication grooves, and the outer wall of the first forming die abuts against the first fuel tank assembly to be hot-pressed; a plurality of first demolding grooves are formed on both the upper and lower surfaces of the third template;

[0026] The fourth template is detachably connected to the third template; two top mating grooves are integrally formed on the surface of the fourth template facing the third template; after the first fuel tank assembly to be hot-pressed is laid in the top mating grooves, the top outer wall of the first forming die abuts against the first fuel tank assembly to be hot-pressed in the top mating grooves; a plurality of second demolding grooves are formed on the surface of the fourth template facing the third template.

[0027] By adopting the above technical solution, the special mold for the first fuel tank assembly can be used to realize the batch production of the first fuel tank assembly, improve the production effect of this application and ensure the quality of this application.

[0028] Preferably, the special mold for the second fuel tank assembly includes a second bottom template, a second intermediate template, a first side template, a second side template, a third side template, a fourth side template, a second top mold, and a second forming cavity. After the second bottom template, the second intermediate template, the first side template, the second side template, the third side template, the fourth side template, and the second top mold are assembled, a second forming cavity is formed inside. The outer shape of the second forming cavity is the same as that of the second fuel tank assembly;

[0029] A second channel is formed on the side wall of the second bottom template; a second limiting mold groove is formed on the surface of the second bottom template; a second communication hole connecting the second channel and the second limiting mold groove is formed on the second bottom template;

[0030] The second intermediate template is detachably connected to the second bottom template; a second groove is formed on the surface of the second intermediate template facing the second bottom template; a first through groove is formed through the upper and lower surfaces of the second intermediate template; a second positioning bump is formed on the surface of the second intermediate template facing away from the second bottom template; the second positioning bump abuts against the bottom of the second forming cavity;

[0031] The first side template and the second side template have the same structure. Taking the first side template as an example, a first convex plate is integrally formed on the surface of the first side template along its own length direction; the surface of the first convex plate facing away from the first side template abuts against the side wall of the second positioning bump; a side wall laying groove is formed on the first convex plate; the side wall of the second forming cavity is fitted into the side wall laying groove; a third demolding groove is formed on the surface of the first side template;

[0032] The third side template is detachably connected between the first side template and the second side template; a second convex plate is integrally formed on the surface of the third side template along its length direction; the surface of the second convex plate facing away from the third side template abuts against the side wall of the second positioning convex block; the side wall of the second convex plate abuts against the first convex plate; the second convex plate is integrally formed with a first fitting block that fits into the installation groove on the second fuel tank assembly; a fourth demolding groove is formed on the surface of the third side template.

[0033] The fourth side template is detachably connected between the first side template and the second side template; a third convex plate is integrally formed on the surface of the fourth side template along its length direction; the side wall of the third convex plate abuts against the side wall of the second positioning convex block; the side wall of the third convex plate abuts against the first convex plate; a second fitting groove is formed on the third convex plate; the second fitting groove is fitted with the special-shaped curved surface shell on the second fuel tank assembly; a top mold positioning groove is formed on the third convex plate; a fifth demolding groove is formed on the surface of the fourth side template.

[0034] A fourth convex plate is integrally formed on the surface of the second top mold along its length direction; the fourth convex plate is integrally formed with a third fitting groove; the third fitting groove is fitted with the top of the second fuel tank assembly; a sixth demolding groove is formed on the surface of the second top mold.

[0035] By adopting the above technical solution, the above special mold for the second fuel tank assembly can realize the batch production of the second fuel tank assembly, improve the production effect of this application and ensure the quality of this application.

[0036] Preferably, in step four, the surface of the first connecting plate coated with the epoxy resin composition and the surface of the second connecting plate member coated with the epoxy resin composition are overlapped, and the overlapped area is hot-pressed by a hot press plate. At the same time, the first connection hole and the second connection hole of the first fuel tank assembly, the detector prefabrication of the second fuel tank assembly, and the oil filling port of the second fuel tank assembly are sealed and communicated with a pressure pump. The pressure is controlled at 0.2 - 0.3 MPa, the hot pressing pressure is 400 - 600 N, and the hot pressing time is 20 - 40 min. After hot pressing, it is naturally cooled to obtain a finished carbon fiber composite fuel tank.

[0037] By adopting the above technical solution, the quality of the hot pressing fixed connection between the first connecting plate and the second connecting plate member can be ensured, and this application is given good oil resistance and does not leak oil at 0.2 MPa, meeting the customer's requirements.

[0038] In summary, this application has the following advantages:

[0039] 1. The carbon fiber composite fuel tank produced by this application is not only light in texture, but also has good mechanical strength and oil resistance, and does not leak oil under a pressure of 0.2 MPa.

[0040] 2. The preparation process of this application is relatively simple, facilitating the realization of the purpose of industrial mass production and processing. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 It is a schematic diagram of the overall structure in an embodiment of this application, mainly showing the connection structure of the first fuel tank assembly and the second fuel tank assembly.

[0042] Figure 2 It is a schematic diagram of the structure of the first fuel tank assembly in an embodiment of this application.

[0043] Figure 3 It is a schematic diagram of the structure of the second fuel tank assembly in an embodiment of this application.

[0044] Figure 4 It is a schematic diagram of the overall layer structure in an embodiment of this application.

[0045] Figure 5 It is a cross-sectional view of the special mold for the first fuel tank assembly in this application.

[0046] Figure 6 It is a schematic diagram of the structure of the first bottom template in the special mold for the first fuel tank assembly in this application.

[0047] Figure 7 It is a schematic diagram of the structure of the second template in the special mold for the first fuel tank assembly in this application.

[0048] Figure 8 It is a schematic diagram of the structure of the connection between the second template and the first forming mold in the special mold for the first fuel tank assembly in this application.

[0049] Figure 9 It is a schematic diagram of the structure of the third template in the special mold for the first fuel tank assembly in this application.

[0050] Figure 10 It is a schematic diagram of the connection structure between the fourth template and the first forming mold in the special mold for the first fuel tank assembly in this application.

[0051] Figure 11 It is a cross-sectional view of the special mold for the second fuel tank assembly in this application.

[0052] Figure 12 It is a partial cross-sectional view of the special mold for the second fuel tank assembly in this application, mainly showing the structure of the second bottom template.

[0053] Figure 13 It is a schematic diagram of the structure of the second bottom template in the special mold for the second fuel tank assembly in this application.

[0054] Figure 14 It is a schematic diagram of the structure of the second intermediate template in the special mold for the second fuel tank assembly in this application.

[0055] Figure 15 It is a schematic diagram of the connection structure of the first side template, the second intermediate template, and the second bottom template in the special mold for the second fuel tank assembly of the present application.

[0056] Figure 16 It is a schematic diagram of the connection structure of the first side template, the second intermediate template, the second bottom template, and the second forming cavity in the special mold for the second fuel tank assembly of the present application.

[0057] Figure 17 It is a schematic diagram of the connection structure of the first side template, the second intermediate template, the second bottom template, and the third side template in the special mold for the second fuel tank assembly of the present application.

[0058] Figure 18 It is a schematic diagram of the connection structure of the first side template, the second side template, the second intermediate template, the second bottom template, the third side template, and the second forming cavity in the special mold for the second fuel tank assembly of the present application.

[0059] Figure 19 It is a schematic diagram of the connection structure of the first side template, the second intermediate template, the second bottom template, the fourth side template, and the second forming cavity in the special mold for the second fuel tank assembly of the present application.

[0060] Figure 20 It is a schematic diagram of the connection structure of the second top mold and the second forming cavity in the special mold for the second fuel tank assembly of the present application.

[0061] 1. First fuel tank assembly; 101. Upper warp knitted resin impregnated carbon fiber cloth; 102. Lower warp knitted resin impregnated carbon fiber cloth; 103. 0° resin impregnated carbon fiber cloth; 104. 90° resin impregnated carbon fiber cloth; 11. First rectangular housing; 12. Rectangular convex housing; 13. First connection hole; 14. Second connection hole; 15. First connection plate; 2. Second fuel tank assembly; 21. Second fuel tank housing; 211. Second housing; 212. Special-shaped curved surface housing; 213. Installation groove; 214. Oil filling port; 215. Detector preform; 22. Second connection plate member; 3. Special mold for the first fuel tank assembly; 30. Cavity; 31. First bottom template; 311. First air inlet channel; 312. First limiting mold groove; 313. First air inlet hole; 32. Second template; 321. First through groove; 322. First positioning convex block; 323. Second communication groove; 324. Chamfered convexity; 33. Third template; 331. Bottom fitting groove; 332. Third communication groove; 333. First demolding groove; 34. Fourth template; 341. Top fitting groove; 342. Second demolding groove; 35. First forming mold; 4. Special mold for the second fuel tank assembly; 40. Second intermediate template; 401. Second mold cavity; 402. First through groove; 403. Second positioning convex block; 41. Second bottom template; 411. Second hole; 412. Second limiting mold groove; 413. Second communication hole; 42. First side template; 421. First convex plate; 422. Side wall laying groove; 423. Third demolding groove; 43. Second side template; 44. Third side template; 441. Second convex plate; 442. First fitting block; 443. Fourth demolding groove; 45. Fourth side template; 451. Third convex plate; 452. Second fitting groove; 453. Top grinding positioning groove; 454. Fifth demolding groove; 46. Second top mold; 461. Fourth convex plate; 462. Third fitting groove; 463. Sixth demolding groove; 47. Second forming cavity. Detailed implementation manners

[0062] The following further elaborates on this application in conjunction with the accompanying drawings and embodiments. Embodiment

[0063] Refer to Figure 1 , a carbon fiber composite fuel tank disclosed in this application, including a first fuel tank assembly 1 and a second fuel tank assembly 2 integrally hot-pressed on the first fuel tank assembly 1, that is, the first fuel tank assembly 1 is hot-pressed and fixedly connected to the second fuel tank assembly 2 to form a complete carbon fiber composite fuel tank.

[0064] Refer to Figure 1 and Figure 2, the specific structure of the first fuel tank assembly 1 is as follows: The first fuel tank assembly 1 includes a first rectangular housing 11. At one end side of the upper surface of the first rectangular housing 11, a rectangular convex housing 12 is integrally formed. One side surface of the rectangular convex housing 12 is flush with the side surface of the first rectangular housing 11. The rectangular convex housing 12 is provided with a first connection hole 13 and a second connection hole 14 penetrating through the upper and lower surfaces. The diameter of the first connection hole 13 is larger than that of the second connection hole 14, and both the first connection hole 13 and the second connection hole 14 are reserved pipe connection vacancies. The connecting line direction of the central axes of the second connection hole 14 and the first connection hole 13 in the same plane is consistent with the width direction of the first rectangular housing 11. A first connecting plate 15 is integrally hot-pressed on the periphery of the first rectangular housing 11, and the bottom surface of the first connecting plate 15 is flush with the bottom surface of the first rectangular housing 11.

[0065] Referring to Figure 1 and Figure 3 , the specific structure of the second fuel tank assembly 2 is as follows: The second fuel tank assembly 2 includes a second fuel tank housing 21 and a second connecting plate member 22, and the second connecting plate member 22 is integrally formed on the second fuel tank housing 21. The figure formed by the vertical projection of the first connecting plate 15 falls within the figure formed by the vertical projection of the second connecting plate member 22, and the size of the figure formed by the vertical projection of the first connecting plate 15 is smaller than the size of the figure formed by the vertical projection of the second connecting plate member 22, that is, the size of the figure formed by the vertical projection of the first connecting plate 15 is 0.8 - 0.85 times the size of the figure formed by the vertical projection of the second connecting plate member 22. The first connecting plate 15 and the second connecting plate member 22 are stacked together, and the stacked part of the first connecting plate 15 and the second connecting plate member 22 is subjected to hot-pressing treatment, so that the first fuel tank assembly 1 is fixedly connected to the second fuel tank assembly 2 by hot-pressing to form a complete carbon fiber composite fuel tank.

[0066] Referring to Figure 4 , the interlayer structure of the carbon fiber tissue formed inside the first fuel tank assembly 1 and the second fuel tank assembly 2 is the same. Taking the first fuel tank assembly 1 as an example, the first fuel tank assembly 1 includes an upper layer warp-knitted resin-impregnated carbon fiber cloth 101, a lower layer warp-knitted resin-impregnated carbon fiber cloth 102, a 0° resin-impregnated carbon fiber cloth 103, and a 90° resin-impregnated carbon fiber cloth 104. Preferably, in the first fuel tank assembly 1 of the present application, there is one upper layer warp-knitted resin-impregnated carbon fiber cloth 101, one lower layer warp-knitted resin-impregnated carbon fiber cloth 102, four 0° resin-impregnated carbon fiber cloths 103, and a single 90° resin-impregnated carbon fiber cloth 104.

[0067] Referring to Figure 4, the 0° resin-impregnated carbon fiber cloth 103 is integrally formed between the upper warp-knitted resin-impregnated carbon fiber cloth 101 and the lower warp-knitted resin-impregnated carbon fiber cloth 102. The 90° resin-impregnated carbon fiber cloth 104 is also integrally formed between the upper warp-knitted resin-impregnated carbon fiber cloth 101 and the lower warp-knitted resin-impregnated carbon fiber cloth 102. In addition, two layers of 0° resin-impregnated carbon fiber cloth 103 are integrally formed between the 90° resin-impregnated carbon fiber cloth 104 and the lower warp-knitted resin-impregnated carbon fiber cloth 102. Another two layers of 0° resin-impregnated carbon fiber cloth 103 are integrally formed between the 90° resin-impregnated carbon fiber cloth 104 and the upper warp-knitted resin-impregnated carbon fiber cloth 101.

[0068] Reference Figure 5 , the special mold 3 for the first fuel tank assembly includes a first bottom template 31, a second template 32, a third template 33, a fourth template 34, and a first forming mold 35. Combining Figure 8 , wherein, the structure of the first forming mold 35 is the same as that of the first fuel tank assembly 1, but the dimensions are different. The first bottom template 31 and the second template 32 are connected by bolts. The second template 32 and the third template 33 are connected by bolts. The third template 33 and the fourth template 34 are connected by bolts. The first forming mold 35 is arranged inside the cavity 30 formed by assembling the first bottom template 31, the second template 32, the third template 33, and the fourth template 34. A gap is reserved between the first forming mold 35 and the cavity 30, so that the outer wall of the first forming mold 35 abuts against the first fuel tank assembly to be hot-pressed.

[0069] Reference Figure 5 and Figure 6 , a first air inlet channel 311 is vertically opened at the center of one side surface of the first bottom template 31. Only one end of the first air inlet channel 311 communicates with the outside, and is used to introduce air pressure into the formed cavity. The central axis direction of the first air inlet channel 311 is consistent with the length direction of the first bottom template 31. Two mutually spaced first limiting mold grooves 312 are formed on the surface of the first bottom template 31. The first limiting mold groove 312 is used to form the first connecting plate 15. A first air inlet hole 313 is vertically opened at the center of the bottom surface of the first limiting mold groove 312 of the first bottom template 31. The first air inlet hole 313 connects the first air inlet channel 311 and the first limiting mold groove 312 together.

[0070] Reference Figure 7 and Figure 8, the second template 32 is provided with two first through grooves 321 that penetrate the upper and lower surfaces and are spaced apart from each other and have the same shape. The vertical projection of the first through groove 321 falls inside the vertical projection of the first limit die groove 312. A first positioning bump 322 is formed on the surface of the second template 32, and a second communication groove 323 having the same specification as the first through groove 321 is integrally formed on the first positioning bump 322. The vertical projection of the second communication groove 323 coincides with the vertical projection of the first through groove 321. A chamfered protrusion 324 is integrally formed on the surface of the first positioning bump 322. After laying the first fuel tank assembly to be hot-pressed, the bottom surface of the first forming die 35 can abut against the first positioning bump 322, and the first forming die 35 can abut against the chamfered protrusion 324.

[0071] Reference Figure 9 , combined with Figure 5 , the third template 33 is detachably connected to the second template 32 by bolts. A bottom fitting groove 331 is formed on the surface of the third template 33 facing the second template 32, so that the first positioning bump 322 can be fitted inside the bottom fitting groove 331. The third template 33 is provided with two spaced-apart third communication grooves 332 penetrating therethrough. After the special die 3 for the first fuel tank assembly is assembled and the first fuel tank assembly to be hot-pressed is laid, the first forming die 35 can pass through the third communication grooves 332, and the outer wall of the first forming die 35 abuts against the first fuel tank assembly to be hot-pressed. In order to facilitate the disassembly of the die, four first demolding grooves 333 are formed on both the upper and lower surfaces of the third template 33.

[0072] Reference Figure 5 and Figure 10 , the fourth template 34 is detachably connected to the third template 33 by bolts. Two spaced-apart top fitting grooves 341 are integrally formed on the surface of the fourth template 34 facing the third template 33. After the first fuel tank assembly to be hot-pressed is laid in the top fitting grooves 341, the outer wall of the top of the first forming die 35 abuts against the first fuel tank assembly to be hot-pressed in the top fitting grooves 341. In order to facilitate the disassembly of the die, four second demolding grooves 342 are formed on the surface of the fourth template 34 facing the third template 33.

[0073] Reference Figure 11 and Figure 12 , the special die 4 for the second fuel tank assembly includes a second bottom template 41, a second intermediate template 40, a first side template 42, a second side template 43, a third side template 44, a fourth side template 45, a second top die 46, and a second forming cavity 47. After the second bottom template 41, the second intermediate template 40, the first side template 42, the second side template 43, the third side template 44, the fourth side template 45, and the second top die 46 are assembled, a second forming cavity 47 is formed inside. The outer shape of the second forming cavity 47 is the same as that of the second fuel tank assembly 2.

[0074] Reference Figure 11 andFigure 12 The second bottom template 41 and the second intermediate template 40 are detachably connected together by bolts. The lower bottom surfaces of the first side template 42, the second side template 43, the third side template 44, and the fourth side template 45 are detachably connected to the second intermediate template 40 by bolts, and their upper bottom surfaces are detachably connected to the second top mold 46 by bolts.

[0075] Reference Figure 12 Combined with Figure 13 As shown in the figure, a second channel 411 is vertically opened at the center of the side wall of the second bottom template 41. One end of the second channel 411 is closed and the other end communicates with the outside. A second limiting mold groove 412 is formed on the surface of the second bottom template 41 for forming the second connecting plate member 22 of the second fuel tank assembly 2. A second communication channel 413 is vertically opened at the center of the bottom of the second limiting mold groove 412 of the second bottom template 41. The second channel 411 and the second limiting mold groove 412 are connected together through the second communication channel 413.

[0076] Reference Figure 14 Combined with Figure 12 As shown in the figure, a second mold groove 401 is formed on the surface of the second intermediate template 40 facing the second bottom template 41. A first through groove 402 is formed through the upper and lower surfaces of the second intermediate template 40. A second positioning convex block 403 is formed on the surface of the second intermediate template 40 facing away from the second bottom template 41, and the inner wall of the second positioning convex block 403 is flush with the inner wall of the first through groove 402. The second positioning convex block 403 abuts against the bottom of the second forming cavity 47.

[0077] Reference Figure 15 As shown in the figure, the first side template 42 and the second side template 43 have the same structure. Taking the first side template 42 as an example, a first convex plate 421 is integrally formed on the surface of the first side template 42 along its own length direction. The end face of the first convex plate 421 is flush with the end face of the first side template 42. The linear distance from the side face of the first convex plate 421 to the nearest side face of the second side template 43 is equal. The surface of the first convex plate 421 facing away from the first side template 42 abuts against the side wall of the second positioning convex block 403. A side wall laying groove 422 is formed on the surface of the first convex plate 421 facing away from the first side template 42, so that the side wall of the second forming cavity 47 can be fitted into the side wall laying groove 422 for limiting. For the convenience of mold removal, two third mold removal grooves 423 are formed on the surface of the first side template 42 facing the first convex plate 421. The two third mold removal grooves 423 are respectively located on both sides of the first convex plate 421.

[0078] Reference Figure 17 And 18, the third side formwork 44 is detachably connected between the first side formwork 42 and the second side formwork 43 by bolts. Specifically, a second convex plate 441 is integrally formed on the surface of the third side formwork 44 along its length direction. One end face of the second convex plate 441 is flush with the end face of the third side formwork 44, and an installation space for the second top form 46 is reserved at the other end face. The linear distances from the side surface of the second convex plate 441 to the nearest side surface of the third side formwork 44 are equal.

[0079] Reference Figure 17 and 18 , the surface of the second convex plate 441 facing away from the third side formwork 44 abuts against the side wall of the second positioning convex block 403. The side wall of the second convex plate 441 abuts against the surface of the first convex plate 421. The second convex plate 441 is integrally formed with a first fitting block 442, and the first fitting block 442 can be fitted into the installation groove 213 on the second fuel tank assembly 2. For the convenience of form removal, two fourth form removal grooves 443 are formed on the surface of the third side formwork 44 facing the second convex plate 441, and the two fourth form removal grooves 443 are respectively located on both sides of the second convex plate 441.

[0080] Reference Figure 19 , the fourth side formwork 45 is detachably connected between the first side formwork 42 and the second side formwork 43 by bolts. A third convex plate 451 is integrally formed on the surface of the fourth side formwork 45 along its length direction. One end of the third convex plate 451 is flush with the side wall of the second convex plate 441. The side wall of the third convex plate 451 abuts against the side wall of the second positioning convex block 403, and the side wall of the third convex plate 451 abuts against the surface of the first convex plate 421.

[0081] Reference Figure 19 , a second fitting groove 452 is formed on the surface of the third convex plate 451 facing away from the fourth side formwork 45. The second fitting groove 452 is fitted with the special-shaped curved surface shell 212 on the second fuel tank assembly 2. A top grinding positioning groove 453 is formed on the third convex plate 451 to facilitate the fitting and installation of the second top form 46. For the convenience of disassembly, two fifth form removal grooves 454 are formed on the surface of the fourth side formwork 45. The two fifth form removal grooves 454 are respectively located on both sides of the third convex plate 451.

[0082] Reference Figure 20 , a fourth convex plate 461 is integrally formed on the surface of the second top form 46 along its length direction, and a third fitting groove 462 is integrally formed on the fourth convex plate 461. The third fitting groove 462 is fitted with the top of the second fuel tank assembly 2. For the convenience of disassembly, four sixth form removal grooves 463 are formed on the surface of the second top form 46.

[0083] A preparation method of a carbon fiber composite fuel tank includes the following steps:

[0084] Step 1, preparing the first fuel tank assembly 1 by using the first fuel tank assembly special mold 3:

[0085] Step 1.1: Bolt the third template 33 and the fourth template 34 together, heat to 40°C, and apply a water-based release agent on the inner walls of the top matching groove 341, the third connecting groove 332 and the bottom fitting groove 331; the outer surface of the first molding mold 35 is also coated with a water-based release agent;

[0086] At the same time, the upper layer of warp and weft knitted resin impregnated carbon fiber cloth, the lower layer of warp and weft knitted resin impregnated carbon fiber cloth, the 0° resin impregnated carbon fiber cloth, and the 90° resin impregnated carbon fiber cloth are cut; the upper layer of warp and weft knitted resin impregnated carbon fiber cloth and the lower layer of warp and weft knitted resin impregnated carbon fiber cloth are specifically 3K twill warp knitted carbon fiber resin impregnated cloth; the 0° resin impregnated carbon fiber cloth is 1500#UD, and the carbon fibers are arranged along the 0° direction; the 90° resin impregnated carbon fiber cloth is 1500#UD, and the carbon fibers are arranged along the 90° direction;

[0087] Step 1.2: 307×50 carbon fiber long strips, 3K twill warp knitted carbon fiber resin impregnated cloth, two layers of 0° resin impregnated carbon fiber cloth, one layer of 90° resin impregnated carbon fiber cloth, two layers of 0° resin impregnated carbon fiber cloth, and 3K twill warp knitted carbon fiber resin impregnated cloth are sequentially laid on the bottom surface of the top matching groove 341, the two side surfaces of the top matching groove 341 along the width direction of the fourth template 34, and the two side surfaces of the third connecting groove 332 along the width direction of the third template 33;

[0088] Step 1.3: 3K twill warp knitted carbon fiber resin impregnated cloth, two layers of 0° resin impregnated carbon fiber cloth of corresponding shape, one layer of 90° resin impregnated carbon fiber cloth of corresponding shape, two layers of 0° resin impregnated carbon fiber cloth of corresponding shape, and 3K twill warp knitted carbon fiber resin impregnated cloth are laid in sequence on the two side surfaces of the top matching groove 341 along the length direction of the fourth template 34 and the two side surfaces of the third connecting groove 332 along the length direction of the third template 33 according to the plane shape; the 3K twill warp knitted carbon fiber resin impregnated cloth laid at the bottom is overlapped with the 3K twill warp knitted carbon fiber resin impregnated cloth in step 1.1 by 10-15mm, and where it cannot be overlapped, another 3K twill is used for overlap, with an overlap of 10-15mm. After the laying is completed, the texture of the 3K twill warp knitted carbon fiber resin impregnated cloth laid at the bottom is consistent with the 3K twill warp knitted carbon fiber resin impregnated cloth laid at the top;

[0089] Step 1.4: The bottom surface of the bottom fitting groove 331 is sequentially paved with flanges, 3K twill warp knitted carbon fiber resin impregnated cloth, two layers of 0° resin impregnated carbon fiber cloth of corresponding shape, one layer of 90° resin impregnated carbon fiber cloth of corresponding shape, two layers of 0° resin impregnated carbon fiber cloth of corresponding shape, and 3K twill warp knitted carbon fiber resin impregnated cloth; wherein the 3K twill warp knitted carbon fiber resin impregnated cloth laid on the bottom and the top is turned down inside and overlapped with the carbon fiber cloth laid in step 1.3 on the side, with an overlap of 10-15mm;

[0090] Step 1.5: Fit the first forming die 35 into the top mating groove 341, the third communication groove 332, and the bottom fitting groove 331, press the flange on the bottom fitting groove 331, and put in silicone.

[0091] Step 1.6: Bolt the first bottom template 31 and the second template 32 together, and close the mold with the half-mold in Step 1.5. There should be no foreign objects or excess material at the mold joint.

[0092] Step 1.7: Place the mold in the center on the upper press. The temperature of the press is 145°C. Perform molding on the upper press. Hold the press, control the pressure at 4 - 5 grids, and the starting air pressure is 0.2 Mpa. Pay attention that the air injection speed should not be too fast to prevent instant bag explosion.

[0093] Step 1.8: Slowly release the air after 300S. After the air is released, increase the pressure to 0.6 Mpa and keep it warm for 3000S.

[0094] Step 1.9: After the heat preservation ends, first release the air, then remove the air nozzle, and finally relieve the pressure to open the mold. Clean the mold to prepare for the production of the next mold, and obtain the first fuel tank assembly 1.

[0095] At the same time, use the special mold 4 for the second fuel tank assembly to prepare the second fuel tank assembly 2:

[0096] S1.1: Lay grooves on the side walls of the first side template 42, lay grooves on the side walls of the second side template 43, the first fitting block 442 of the third side template 44, and the second fitting groove 452 of the fourth side template 45. Coat with a water-based mold release agent at a heating temperature of 40°C. Heat the second forming cavity 47 to 40°C and coat the outer surface of the second forming cavity 47 with a water-based mold release agent.

[0097] At the same time, cut the upper warp-knitted resin-impregnated carbon fiber cloth, the lower warp-knitted resin-impregnated carbon fiber cloth, the 0° resin-impregnated carbon fiber cloth, and the 90° resin-impregnated carbon fiber cloth. The upper warp-knitted resin-impregnated carbon fiber cloth and the lower warp-knitted resin-impregnated carbon fiber cloth are specifically 3K twill warp-knitted carbon fiber resin-impregnated cloth. The 0° resin-impregnated carbon fiber cloth is 1500# UD, and the carbon fibers are arranged along the 0° direction. The 90° resin-impregnated carbon fiber cloth is 1500# UD, and the carbon fibers are arranged along the 90° direction.

[0098] S1.2: Lay 3K twill warp-knitted carbon fiber resin-impregnated cloth, two layers of 0° resin-impregnated carbon fiber cloth of corresponding shape, one layer of 90° resin-impregnated carbon fiber cloth of corresponding shape, two layers of 0° resin-impregnated carbon fiber cloth of corresponding shape, and 3K twill warp-knitted carbon fiber resin-impregnated cloth in sequence on the bottom of the third fitting groove 462 of the second top mold 46 according to the shape of the bottom surface of the third fitting groove 462. Among them, a groove for reserving the detector preform 215 is formed in the third fitting groove 462.

[0099] S1.3: In the groove of the third fitting groove 462 reserved for forming the detector preform 215, lay 3K twill warp knitted carbon fiber resin impregnated cloth, two layers of 0° resin impregnated carbon fiber cloth of corresponding shape, one layer of 90° resin impregnated carbon fiber cloth of corresponding shape, two layers of 0° resin impregnated carbon fiber cloth of corresponding shape, and 3K twill warp knitted carbon fiber resin impregnated cloth in sequence; among them, the inner side of the 3K twill warp knitted carbon fiber resin impregnated cloth is turned down and side-lapped with the carbon fiber cloth laid in step 1.2, with a lap of 10 - 15 mm. For the places where the lap is not enough, use 3K twill to lap additionally, with a lap of 10 - 15 mm.

[0100] S1.4: In the second fitting groove 452 of the fourth side formwork 45, lay 3K twill warp knitted carbon fiber resin impregnated cloth, two layers of 0° resin impregnated carbon fiber cloth of corresponding shape, one layer of 90° resin impregnated carbon fiber cloth of corresponding shape, two layers of 0° resin impregnated carbon fiber cloth of corresponding shape, and 3K twill warp knitted carbon fiber resin impregnated cloth in sequence according to the bottom surface shape of the second fitting groove 452.

[0101] S1.5: On the surface of the second convex plate 441 of the third side formwork 44, lay 3K twill warp knitted carbon fiber resin impregnated cloth, two layers of 0° resin impregnated carbon fiber cloth of corresponding shape, one layer of 90° resin impregnated carbon fiber cloth of corresponding shape, two layers of 0° resin impregnated carbon fiber cloth of corresponding shape, and 3K twill warp knitted carbon fiber resin impregnated cloth in sequence according to the surface shape of the second convex plate 441.

[0102] S1.6: On the outer wall of the first fitting block 442 of the third side formwork 44, lay 3K twill warp knitted carbon fiber resin impregnated cloth, two layers of 0° resin impregnated carbon fiber cloth of corresponding shape, one layer of 90° resin impregnated carbon fiber cloth of corresponding shape, two layers of 0° resin impregnated carbon fiber cloth of corresponding shape, and 3K twill warp knitted carbon fiber resin impregnated cloth in sequence; among them, the laid 3K twill warp knitted carbon fiber resin impregnated cloth is lapped with the 3K twill warp knitted carbon fiber resin impregnated cloth in step 1.5, with a lap of 10 - 15 mm. For the places where the lap is not enough, use 3K twill to lap additionally, with a lap of 10 - 15 mm.

[0103] S1.7: In the groove 422 on the side wall of the first side formwork 42, lay 3K twill warp knitted carbon fiber resin impregnated cloth, two layers of 0° resin impregnated carbon fiber cloth of corresponding shape, one layer of 90° resin impregnated carbon fiber cloth of corresponding shape, two layers of 0° resin impregnated carbon fiber cloth of corresponding shape, and 3K twill warp knitted carbon fiber resin impregnated cloth in sequence; among them, the 3K twill warp knitted carbon fiber resin impregnated cloth laid on the upper part and the bottom is lapped with the 3K twill warp knitted carbon fiber resin impregnated cloth in step 1.5 and the 3K twill warp knitted carbon fiber resin impregnated cloth in step 1.4 respectively, with a lap of 10 - 15 mm. For the places where the lap is not enough, use 3K twill to lap additionally, with a lap of 10 - 15 mm.

[0104] Meanwhile, on the side walls of the second side formwork 43, the laying grooves 422 are successively laid with 3K twill warp-knitted carbon fiber resin impregnated cloth, two layers of 0° resin impregnated carbon fiber cloth of corresponding shape, one layer of 90° resin impregnated carbon fiber cloth of corresponding shape, two layers of 0° resin impregnated carbon fiber cloth of corresponding shape, and 3K twill warp-knitted carbon fiber resin impregnated cloth. Among them, the 3K twill warp-knitted carbon fiber resin impregnated cloth laid on the upper and bottom parts are respectively lapped with the 3K twill warp-knitted carbon fiber resin impregnated cloth in Step 1.5 and the 3K twill warp-knitted carbon fiber resin impregnated cloth in Step 1.4, with a lap of 10 - 15 mm. Where the lap is insufficient, it is additionally lapped with 3K twill, with a lap of 10 - 15 mm.

[0105] S1.8: Bolt the first side formwork 42, the second side formwork 43, the third side formwork 44, and the fourth side formwork 45 together. Fold the 3K twill warp-knitted carbon fiber resin impregnated cloth in Steps 1.4 - 1.7, and then bolt the second intermediate formwork 40 together, so that the folded 3K twill warp-knitted carbon fiber resin impregnated cloth fits the surface of the second positioning convex block 403. The connection of the 3K twill warp-knitted carbon fiber resin impregnated cloth is lapped with 3K twill, with a lap of 10 - 15 mm.

[0106] S1.9: Lay a release film in the second groove 401, place a silica gel sheet to fit the second groove 401, place an air bag, and close the second bottom formwork 41. There should be no foreign objects or excess material at the mold closing seam.

[0107] S1.10: Place the mold in the middle of the upper press. The press temperature is 145°C. The upper press is used for molding. The press is held, and the pressure is controlled at 4 - 5 grids. The initial air pressure is 0.2 Mpa. Note that the air filling speed should not be too fast to prevent instant bag explosion.

[0108] Step 1.11: After 300S, slowly release the air. After the air is released, increase the pressure to 0.4 Mpa and keep it warm for 2500S.

[0109] Step 1.12: After the heat preservation is completed, first release the air, then remove the air nozzle, and finally relieve the pressure and open the mold. Clean the mold to prepare for the next mold production to obtain the second fuel tank assembly 2.

[0110] Step Two: Demold and grind the burrs to obtain the first fuel tank assembly 1 and the second fuel tank assembly 2.

[0111] Step Three: Coat the lower surface of the first connecting plate 15 with an epoxy resin composition and cure it into a gel state at 80°C for standby. Meanwhile, coat the lower surface of the second connecting plate 22 with an epoxy resin composition and cure it into a gel state at 80°C for standby. The epoxy resin combination used is the same material as the epoxy resin composition used in the 3K twill warp-knitted carbon fiber resin impregnated cloth.

[0112] Step 4: Superpose the surface of the first connecting plate 15 coated with the epoxy resin composition and the surface of the second connecting plate member 22 coated with the epoxy resin composition, and perform hot pressing treatment on the superposed area by pressing with a hot pressing plate. At the same time, use rubber plugs to block the first connection hole 13, the second connection hole 14 of the first fuel tank assembly 1, and the detector preform 215 of the second fuel tank assembly 2. The oil filling port 214 of the second fuel tank assembly 2 is hermetically connected to a pressure pump, and the pressure is controlled at 0.3 MPa. The hot pressing pressure is 500 N, and the hot pressing time is 25 min. After the hot pressing is completed, cool naturally, and remove the blocked rubber plugs to obtain the finished carbon fiber composite fuel tank. The preparation process of the present application is relatively simple, and the produced carbon fiber composite fuel tank is not only light in texture, but also has good mechanical strength, oil resistance and corrosion resistance, and does not leak oil under a pressure of 0.2 MPa.

[0113] This specific embodiment is only an interpretation of the present application, and it is not a limitation to the present application. After reading this specification, those skilled in the art can make modifications to this embodiment without creative contributions according to needs, but as long as they are within the scope of the claims of the present application, they are protected by the patent law.

Claims

1. A preparation method of a carbon fiber composite fuel tank, characterized in that: The carbon fiber composite fuel tank includes a first fuel tank assembly (1) and a second fuel tank assembly (2). The first fuel tank assembly (1) is fixedly connected to the second fuel tank assembly (2) by hot pressing to form a complete carbon fiber composite fuel tank. The first fuel tank assembly (1) includes a first rectangular housing (11), and a first connecting plate (15) is fixedly connected to the periphery of the first rectangular housing (11). The bottom surface of the first connecting plate (15) is flush with the bottom surface of the first rectangular housing (11). The second fuel tank assembly (2) includes a second fuel tank housing (21), and a second connecting plate member (22) is integrally formed on the second fuel tank housing (21). The first connecting plate (15) and the second connecting plate member (22) are fixed by hot pressing. The manufacturing method includes the following steps: Step 1: Use a special mold (3) for the first fuel tank assembly to prepare the first fuel tank assembly (1), and at the same time use a special mold (4) for the second fuel tank assembly to prepare the second fuel tank assembly (2); Step 2: Demold and polish the burrs to obtain the first fuel tank assembly (1) and the second fuel tank assembly (2); Step 3: Coat the lower surface of the first connecting plate (15) with an epoxy resin composition, cure it into a gel state for standby. At the same time, coat the lower surface of the second connecting plate member (22) with an epoxy resin composition, cure it into a gel state for standby; Step 4: Hot press the surface of the first connecting plate (15) coated with the epoxy resin composition and the surface of the second connecting plate member (22) coated with the epoxy resin composition, and cool to obtain the finished carbon fiber composite fuel tank; Among them, the special mold (3) for the first fuel tank assembly includes a first bottom template (31), a second template (32), a third template (33), a fourth template (34), and a first forming mold (35). The first forming mold (35) has the same structure as the first fuel tank assembly (1), but different dimensions. The first forming mold (35) is arranged in a cavity (30) formed by assembling the first bottom template (31), the second template (32), the third template (33), and the fourth template (34). A gap is reserved between the first forming mold (35) and the cavity (30) so that the outer wall of the first forming mold (35) abuts against the first fuel tank assembly to be formed by hot pressing; The first bottom template (31) is provided with a first air inlet channel (311); two spaced first limiting die grooves (312) are provided on the surface of the first bottom template (31); a first air inlet hole (313) communicating the first air inlet channel (311) and the first limiting die groove (312) is provided on the surface of the first bottom template (31); the first bottom template (31) is detachably connected to the second template (32); The second template (32) is provided with two first through grooves (321) penetrating through the upper and lower surfaces; a first positioning bump (322) is formed on the surface of the second template (32); a second communication groove (323) having the same specification as the first through groove (321) is integrally formed on the first positioning bump (322); a chamfered protrusion (324) is integrally formed on the surface of the first positioning bump (322); after laying the first fuel tank assembly to be hot-pressed, the bottom surface of the first forming die (35) can be in contact with the first positioning bump (322), and the first forming die (35) can be in contact with the chamfered protrusion (324); The third template (33) is detachably connected to the second template (32); a bottom fitting groove (331) is provided on the surface of the third template (33) facing the second template (32); the first positioning bump (322) is fitted into the bottom fitting groove (331); two third communication grooves (332) are penetratingly provided on the third template (33); the first forming die (35) can pass through the third communication grooves (332), and the outer wall of the first forming die (35) is in contact with the first fuel tank assembly to be hot-pressed; a plurality of first demolding grooves (333) are provided on both the upper and lower surfaces of the third template (33); The fourth template (34) is detachably connected to the third template (33); two top fitting grooves (341) are integrally formed on the surface of the fourth template (34) facing the third template (33); after laying the first fuel tank assembly to be hot-pressed in the top fitting grooves (341), the outer wall of the top of the first forming die (35) is in contact with the first fuel tank assembly to be hot-pressed in the top fitting grooves (341); a plurality of second demolding grooves (342) are provided on the surface of the fourth template (34) facing the third template (33).

2. The preparation method of a carbon fiber composite fuel tank according to claim 1, characterized in that: The special mold (4) for the second fuel tank assembly includes a second bottom template (41), a second intermediate template (40), a first side template (42), a second side template (43), a third side template (44), a fourth side template (45), a second top mold (46), and a second forming cavity (47). After the second bottom template (41), the second intermediate template (40), the first side template (42), the second side template (43), the third side template (44), the fourth side template (45), and the second top mold (46) are assembled, a second forming cavity (47) is formed inside, and the outer shape of the second forming cavity (47) is the same as that of the second fuel tank assembly (2); A second channel (411) is provided on the side wall of the second bottom template (41); a second limiting die groove (412) is formed on the surface of the second bottom template (41); a second communication hole (413) connecting the second channel (411) and the second limiting die groove (412) is provided on the second bottom template (41). The second intermediate template (40) is detachably connected to the second bottom template (41); a second mold cavity (401) is formed on the surface of the second intermediate template (40) facing the second bottom template (41); a first through groove (402) is formed through the upper and lower surfaces of the second intermediate template (40); a second positioning bump (403) is formed on the surface of the second intermediate template (40) facing away from the second bottom template (41). The first side template (42) and the second side template (43) have the same structure. Taking the first side template (42) as an example, a first convex plate (421) is integrally formed on the surface of the first side template (42) along its own length direction; the surface of the first convex plate (421) facing away from the first side template (42) abuts against the side wall of the second positioning bump (403); a side wall laying groove (422) is formed on the first convex plate (421); a third demolding groove (423) is formed on the surface of the first side template (42). The third side template (44) is detachably connected between the first side template (42) and the second side template (43); a second convex plate (441) is integrally formed on the surface of the third side template (44) along its own length direction; the surface of the second convex plate (441) facing away from the third side template (44) abuts against the side wall of the second positioning bump (403); the side wall of the second convex plate (441) abuts against the first convex plate (421); a first fitting block (442) that fits into the mounting groove (213) on the second fuel tank assembly (2) is integrally formed on the second convex plate (441); a fourth demolding groove (443) is formed on the surface of the third side template (44). The fourth side template (45) is detachably connected between the first side template (42) and the second side template (43); a third convex plate (451) is integrally formed on the surface of the fourth side template (45) along its own length direction; the side wall of the third convex plate (451) abuts against the side wall of the second positioning bump (403); the side wall of the third convex plate (451) abuts against the first convex plate (421); a second fitting groove (452) is formed on the third convex plate (451); the second fitting groove (452) is fitted with the special-shaped curved surface shell (212) on the second fuel tank assembly (2); a top grinding positioning groove (453) is formed on the third convex plate (451); a fifth demolding groove (454) is formed on the surface of the fourth side template (45). A fourth convex plate (461) is integrally formed on the surface of the second top mold (46) along its own length direction; a third fitting groove (462) is integrally formed on the fourth convex plate (461); the third fitting groove (462) is fitted with the top of the second fuel tank assembly (2); a sixth demolding groove (463) is formed on the surface of the second top mold (46).

3. The preparation method of a carbon fiber composite fuel tank according to claim 1, characterized in that: In the fourth step, the surface of the first connecting plate (15) coated with the epoxy resin composition is superposed with the surface of the second connecting plate member (22) coated with the epoxy resin composition, and the superposed area is subjected to hot pressing treatment by using a hot pressing plate. At the same time, the first connection holes (13) and second connection holes (14) of the first fuel tank assembly (1), the detector preform (215) of the second fuel tank assembly (2), and the oil filling port (214) of the second fuel tank assembly (2) are sealed and connected to a pressure pump. The pressure is controlled at 0.2 - 0.3 MPa, the hot pressing pressure is 400 - 600 N, and the hot pressing time is 20 - 40 min. After the hot pressing is completed, it is naturally cooled to obtain the finished carbon fiber composite fuel tank.

4. A carbon fiber composite fuel tank obtained by the method according to any one of claims 1 - 3.

5. A carbon fiber composite fuel tank according to claim 4, characterized in that: One end side of the upper surface of the first rectangular shell (11) is integrally formed with a rectangular convex shell (12); the rectangular convex shell (12) is provided with a first connection hole (13) and a second connection hole (14) penetrating through the upper and lower surfaces; the second fuel tank shell (21) includes a second shell (211) and a special-shaped curved surface shell (212), and the special-shaped curved surface shell (212) is integrally formed on the second shell (211); one side wall of the second shell (211) facing away from the special-shaped curved surface shell (212) is integrally formed with a mounting groove (213); one end of the mounting groove (213) opens through the upper surface of the second shell (211); the upper surface of the second shell (211) is integrally formed with an oil filling port (214) and a detector preform (215); the oil filling port (214) and the detector preform (215) are respectively located on both sides of the opening of the mounting groove (213).

6. A carbon fiber composite fuel tank according to claim 4, characterized in that: The carbon fiber tissue layer structure formed inside the first fuel tank assembly (1) and the second fuel tank assembly (2) is the same; taking the first fuel tank assembly (1) as an example, the first fuel tank assembly (1) includes an upper layer warp knitted resin-impregnated carbon fiber cloth (101), a lower layer warp knitted resin-impregnated carbon fiber cloth (102), a 0° resin-impregnated carbon fiber cloth (103), and a 90° resin-impregnated carbon fiber cloth (104); the 0° resin-impregnated carbon fiber cloth (103) is integrally formed between the upper layer warp knitted resin-impregnated carbon fiber cloth (101) and the lower layer warp knitted resin-impregnated carbon fiber cloth (102); the 90° resin-impregnated carbon fiber cloth (104) is integrally formed between the upper layer warp knitted resin-impregnated carbon fiber cloth (101) and the lower layer warp knitted resin-impregnated carbon fiber cloth (102).

7. A carbon fiber composite fuel tank according to claim 6, characterized in that: The first fuel tank assembly (1) includes a single upper warp-knitted and weft-knitted resin-impregnated carbon fiber cloth (101), a single lower warp-knitted and weft-knitted resin-impregnated carbon fiber cloth (102), four 0° resin-impregnated carbon fiber cloths (103), and a single 90° resin-impregnated carbon fiber cloth (104). Two stacked 0° resin-impregnated carbon fiber cloths (103) are integrally formed between the upper warp-knitted and weft-knitted resin-impregnated carbon fiber cloth (101) and the adjacent 90° resin-impregnated carbon fiber cloth (104); two stacked 0° resin-impregnated carbon fiber cloths (103) are integrally formed between the lower warp-knitted and weft-knitted resin-impregnated carbon fiber cloth (102) and the adjacent 90° resin-impregnated carbon fiber cloth (104).

Images