Press molding member, method for manufacturing the same, and method for manufacturing battery case using press molding member

Abstract

To provide: a semi-cured resin fiber-reinforced composite material intermediate which enables fiber fabric or unidirectional fiber and metal foil to be pressed without displacement during press molding, where the intermediate has high thermal conductivity so that internal heat can be easily released to the outside during use, and where the intermediate can shield electromagnetic waves; and a battery case obtained by processing the intermediate.SOLUTION: A press molding member comprises a metal foil-containing semi-cured fiber-reinforced composite material intermediate material, which is integrated by laminating at least two or more semi-cured resin sheets, fiber fabric or unidirectional fiber, and metal foil.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a press-molding member, a battery case using the press-molding member, and a manufacturing method thereof. [Background technology]

[0002] Fiber-reinforced resin materials, which are made up of fibers and resin, are lightweight and have excellent strength, and are therefore widely used in various industrial applications such as automobile parts, aircraft parts, railway parts, etc. In particular, battery-powered electric vehicles have heavy batteries on board and cannot travel long distances compared to gasoline-powered vehicles, so it is extremely important to reduce the weight of the entire electric vehicle.

[0003] Patent Document 1 discloses the production of a battery case for an electric vehicle using a fiber-reinforced resin material containing carbon fibers in a randomly dispersed state.

[0004] [Patent Document 1] JP 2012-109452 A Summary of the Invention [Problem to be solved by the invention]

[0005] Conventional battery cases for electric vehicles have been made of aluminum as a material for its light weight and strength. However, from the standpoint of strength, it is preferable for the battery cases to have a certain thickness, and as a result, it is not possible to obtain a battery case that is sufficiently light using aluminum alone.

[0006] In recent years, therefore, the use of lightweight, high-strength fiber-reinforced composite materials has been considered as an alternative to aluminum as a material for battery cases. However, fiber-reinforced composite materials have the disadvantage that they have an extremely low electromagnetic wave shielding effect and low thermal conductivity, making it difficult to release heat inside the battery case to the outside. [Means for solving the problem]

[0007] As a result of intensive research, the inventors have discovered that by using a metal foil-containing semi-cured resin fiber-reinforced composite intermediate material in which a semi-cured resin sheet, a woven fabric or unidirectional fiber, and a metal foil are laminated and integrated, the fiber and the metal foil can be pressed without being misaligned during press molding. Furthermore, they discovered that the battery case obtained by press molding has high thermal conductivity, so that it is easy to release internal heat to the outside during use, and that the use of metal foil makes it possible to shield electromagnetic waves, and thus arrived at the present invention. That is, the present invention includes the following. [1] A press molding component comprising a metal foil-containing semi-cured fiber reinforced composite intermediate material in which at least two or more semi-cured resin sheets, a fiber fabric or unidirectional fiber, and a metal foil are laminated and integrated together. [2] The press molding member according to [1], wherein the resin of the semi-cured resin sheet is a thermosetting epoxy resin. [3] The press molding member according to [1], wherein the resin of the semi-cured resin sheet is a filler-containing saturated or unsaturated polyester resin. [4] The press-molded member according to [1], wherein the metal foil has an adhesive sheet for adhering to the resin sheet. [5] The press-molded member according to [1], wherein linear grooves are provided on the surface of the metal foil. [6] The press-molding member according to [1], wherein the fiber fabric or the unidirectional fiber is a glass fiber. [7] The press-molding member according to [1], wherein the fiber fabric or the unidirectional fiber is a carbon fiber. [8] A method for manufacturing a battery case, comprising a step of hot press molding a press molding material described in any one of [1] to [7], wherein the metal foil side is disposed on the inside of the battery case. [9] A method for producing a press-molded member, comprising a step of integrating the metal foil-containing semi-cured resin fiber reinforced composite intermediate material described in [1] using a double belt method. Effect of the Invention

[0008] Components used in automobiles, such as battery cases, are made up of flat parts and parts with complex shapes. A representative material for complex shapes is SMC, which uses short fibers, a type of semi-cured resin fiber-reinforced composite material. However, the weight reduction effect and strength are insufficient, and a technology for laminating prepreg, a long-fiber semi-cured fiber-reinforced composite material, is also being developed to compensate for this. When laminating two semi-cured resin sheets, there are cases where the interface with the metal is misaligned and the expected performance is not achieved. By using an intermediate material in which a semi-cured resin sheet, a long-fiber metal foil-containing semi-cured resin fiber-reinforced composite material intermediate, a fiber fabric or unidirectional fiber, and a metal foil are laminated and integrated, the interface and fibers can be pressed without being misaligned due to the effect of the metal foil in the press molding process. In addition, a battery case made of a material obtained by hardening a press molding component containing metal foil obtained by pressing has a high thermal conductivity due to the continuous metal layer, and is easy to release internal heat to the outside during use. In terms of both process and performance, it is very effective in solving problems as a component. [Brief description of the drawings]

[0009] [Figure 1] FIG. 1 is a cross-sectional view of a metal foil-containing semi-cured fiber-reinforced composite material intermediate 1A according to a first embodiment. [Diagram 2] FIG. 2 is a cross-sectional view of a metal foil-containing semi-cured fiber reinforced composite material intermediate 1B according to the second embodiment. [Diagram 3] FIG. 3 is a cross-sectional view of a metal foil-containing semi-cured fiber reinforced composite material intermediate 1C according to the third embodiment. [Figure 4] FIG. 4 is a schematic diagram illustrating the process for producing a metal foil-containing semi-cured fiber reinforced composite material intermediate 1A. [Diagram 5] FIG. 5 is a schematic diagram showing grooves 9 provided on the metal foil surface of a metal foil-containing semi-cured fiber reinforced composite material intermediate. [Figure 6] FIG. 6 is a schematic diagram illustrating the manufacturing process of the pressed fiber-reinforced composite material member 11A. [Figure 7]FIG. 7 shows an example of a battery case material obtained by press molding a pressed fiber-reinforced composite material member 11A. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] [Semi-hardened fiber-reinforced composite intermediate] 1 is a cross-sectional view of a metal foil-containing, semi-cured resin fiber-reinforced composite material intermediate 1A according to a first embodiment of the present invention. The metal foil-containing, semi-cured resin fiber-reinforced composite material intermediate 1A is formed by laminating, from the top, a semi-cured resin sheet 5, a fiber fabric 4, a semi-cured resin sheet 5, an adhesive sheet 3, and a metal foil 2 in this order.

[0011] In the metal foil-containing semi-cured resin fiber reinforced composite material intermediate 1A having such a configuration, the fiber reinforced resin layer 5 and the metal foil 2 are firmly bonded by the adhesive sheet 3, so that the fiber fabric 4 and the metal foil 2 can be pressed without being misaligned during press molding.

[0012] The battery case includes a fiber-reinforced composite material pressed molded part 11A obtained by press molding a metal foil-containing semi-cured resin fiber-reinforced composite material intermediate 1A. Since the metal foil 2 is used, the battery case has high thermal conductivity, and is easy to release internal heat to the outside during use, and also has an electromagnetic wave shielding effect.

[0013] The resin constituting the resin layer 5 of the metal foil-containing semi-cured resin fiber reinforced composite material intermediate 1A is not particularly limited as long as it is a material that can be used to produce a fiber reinforced composite material pressed molded part 11A by hot pressing, and may be either a thermosetting resin or a thermoplastic resin. However, from the perspective of ease of molding and the use of the molded metal composite 11A, a thermosetting resin is preferable. Specific examples of resins that can be used include thermosetting or thermoplastic epoxy resins, vinyl ester resins, polyurethane resins, phenolic resins, acrylic resins, polyester resins, polycarbonate resins, polypropylene resins, polyethylene resins, polystyrene resins, vinyl chloride resins, polyamide resins, etc. These may be used alone or in combination. In the state of the metal foil-containing semi-cured resin fiber reinforced composite material intermediate 1A, the resin is in a semi-cured state, but it will harden when hot-pressed to manufacture the battery case.

[0014] Here, the semi-cured state of the resin refers to a state in which the resin is treated at a temperature lower than the temperature at which curing begins in the production of the metal foil-containing semi-cured resin fiber reinforced composite material intermediate 1A. Since the resin is semi-cured but not completely cured, it is in a state where it can be molded into a desired shape by hot pressing.

[0015] The fiber fabric 4 is a sheet-like fabric made by plain or twill weaving of fibers. The fiber of the fiber fabric 4 is not particularly limited as long as it is a material that can be molded by hot pressing, and examples thereof include glass fiber, carbon fiber, aramid fiber (chemical fiber and natural fiber), polyvinyl alcohol fiber, polyester fiber, polyamide fiber, polyethylene fiber, polyparaphenylene benzobisoxazole fiber, etc. Examples of glass fiber include glass fiber using E glass, S glass, D glass, Q glass, etc. In addition, PAN-based carbon fiber made from polyacrylonitrile and pitch-based carbon fiber made from pitch can be used. The carbon fiber in the prepreg is preferably PAN-based carbon fiber, but is not limited thereto.

[0016] The fiber fabric 4 is preferably made of carbon fiber or glass fiber having a thickness of 0.1 mm to 0.5 mm, but is not limited thereto. In the embodiment, an example in which a fiber fabric is used has been given, but in addition to the fiber fabric 4, unidirectional fibers (excluding glass wool) may also be used.

[0017] The two semi-cured resin sheets 5 and the fiber fabric 4 in the metal foil-containing semi-cured resin fiber reinforced composite material intermediate 1A may be made of commercially available prepregs (prepregs composed of two resin layers and plain weave or twill weave fibers sandwiched between them). Even in the case of using such prepregs, the resulting laminate is considered to be included in the metal foil-containing semi-cured resin fiber reinforced composite material intermediate.

[0018] The metal constituting the metal layer 2 is not particularly limited as long as it is a metal that is stable at room temperature to 300° C., and examples of the metal include aluminum, aluminum alloys, magnesium alloys, titanium, titanium alloys, steel, copper, copper alloys, etc. Examples of aluminum alloys that can be used include, but are not limited to, 5000 series such as A5052 which is an Al-Mg system, 2000 series such as A2014 which is an Al-Cu system, and Al-Si-Cu alloys for die casting (JIS standards ADC12, ADC10, etc.). The thickness of the metal layer 2 is usually 0.02 to 2 mm, and preferably about 0.05 to 1.5 mm. This is suitable for easy formation into a desired shape by press molding. If the thickness of the metal layer 2 is less than 0.02 mm, the magnetic field shielding properties may decrease in the low Hz region (particularly 10 MHz or less). If the thickness of the metal layer 2 is excessively large, the weight of the metal foil-containing semi-cured resin fiber reinforced composite material intermediate 1A may become large.

[0019] The adhesive sheet 3 is for bonding the metal foil 2 to the semi-cured resin sheet 5 containing the fiber fabric 4. In the prior art, a pressed laminate was produced by simply stacking the resin-impregnated fiber fabric and the metal foil and pressing them together, but in this case, the resin and the metal foil would shift during pressing, making it difficult to obtain the desired pressed laminate and practically unfeasible. In the metal foil-containing semi-cured fiber reinforced composite intermediate 1A, the fiber fabric 4 and the metal foil 2 are firmly bonded and integrated by the adhesive sheet 3, so that the metal layer 2 does not shift and the desired pressed fiber reinforced composite molded part 11A can be produced by hot pressing.

[0020] The material of the adhesive component of the adhesive sheet 3 is not particularly limited, but examples thereof include epoxy, acrylic, and urethane. In order to adhere the semi-cured resin 5 to the metal layer 2 while it is still semi-cured, an adhesive sheet that has adhesiveness even at room temperature is preferable. Note that a liquid adhesive may be used instead of the adhesive sheet 3, but it is preferable to use an adhesive sheet when manufacturing by the double belt method described below.

[0021] 2 is a cross-sectional view of a metal foil-containing, semi-cured resin fiber-reinforced composite material intermediate 1B according to a second embodiment. The metal foil-containing, semi-cured resin fiber-reinforced composite material intermediate 1B is formed by laminating, from the top, a semi-cured resin sheet 5, a fiber fabric 4, a semi-cured resin sheet 5, a fiber fabric 4, a semi-cured resin sheet 5, an adhesive sheet 3, and a metal foil 2.

[0022] That is, the metal foil-containing semi-cured resin fiber reinforced composite material intermediate 1B is obtained by further laminating a semi-curable resin 5 and a fiber fabric 4 on the metal foil-containing semi-cured resin fiber reinforced composite material intermediate 1A. Note that the thicknesses of the multiple semi-curable resins 5 in Fig. 1 and Fig. 2 may be the same or different, and the types of resins in the multiple semi-curable resins 5 may be the same or different. In this manner, a semi-cured resin layer 5 and a fiber fabric 4 may be repeatedly laminated on the surface opposite to the metal layer of the metal foil-containing semi-cured resin fiber reinforced composite material intermediate 1B.

[0023] 3 is a cross-sectional view of a metal foil-containing semi-cured resin fiber reinforced composite material intermediate 1C according to a third embodiment. In the third embodiment, one of the semi-cured resin layers 5 of the metal foil-containing semi-cured resin fiber reinforced composite material intermediate 1A is made of a filler-containing saturated or unsaturated polyester resin 7. The filler-containing saturated or unsaturated polyester resin is easy to handle and has very high strength due to the filler contained therein. The filler-containing saturated or unsaturated polyester resin is also in a semi-cured state and is included in the category of semi-cured resins. The filler contained in the resin may be carbon fiber, glass fiber, graphite, mica, mineral particulate filler, or the like.

[0024] [Method of manufacturing intermediate of metal foil-containing semi-cured resin fiber reinforced composite material] The production of a metal foil-containing semi-cured resin fiber reinforced composite material intermediate is carried out, for example, by a double belt press method as shown in Fig. 4. Fig. 4 shows an example of the production of a metal foil-containing semi-cured resin fiber reinforced composite material intermediate 1A. The double belt press method uses a double belt device 8, which has two conveyors with built-in heater blocks arranged above and below, to heat, press, roll, and mold the work from above and below. However, when manufacturing the metal foil-attached prepreg 1A for press molding, it is also possible to do so at room temperature without heating. This is because the work is laminated in the semi-cured resin state.

[0025] The double belt press method has been used conventionally in the manufacture of normal prepregs made of resin and fibers, but in the manufacture of metal foil-containing semi-cured resin fiber reinforced composite material intermediate 1A, as shown in Fig. 4, two semi-cured resin layer sheets 5 are provided in the order of semi-cured resin sheet 5, fiber 4, and semi-cured resin sheet 5 from the top, with fiber fabric 4 sandwiched between them. Further below that, an adhesive sheet 3 is laminated so as to be in contact with the semi-cured resin sheet 5, and then a metal foil 2 is laminated so as to be in contact with the adhesive sheet 3, and these are further integrated by the double belt press method to manufacture metal foil-containing semi-cured resin fiber reinforced composite material intermediate 1A.

[0026] Although not shown in the figure, a semi-cured resin sheet 5, a fiber fabric 4, a semi-cured resin sheet 5, a fiber fabric 4, a semi-cured resin sheet 5, an adhesive sheet 3, and a metal foil 2 can be layered from the top and further integrated using a double belt press method to produce a metal foil-containing semi-cured resin fiber reinforced composite material intermediate 1B.

[0027] Similarly, although not shown, a metal foil-containing semi-cured fiber reinforced composite material intermediate 1C can be produced by stacking from the top a filler-containing saturated or unsaturated polyester resin 7, a fiber fabric 4, a filler-containing saturated or unsaturated polyester resin 7, an adhesive sheet 3, and a metal foil 2, and then integrating them using a double belt press method.

[0028] In this case, it is preferable that the metal foil 2 is provided with grooves 9 as shown in FIG. 5, but the shape and number are not particularly limited, and for example, multiple linear grooves can be provided. By providing the grooves 9, in a battery case made of the pressed fiber-reinforced composite material 11A obtained by hot pressing, the contact area between the constituent material and the air increases, making it possible to dissipate heat efficiently. The grooves 9 may be provided at room temperature without applying heat, even if a molding method such as hot pressing is used. Note that by making the grooves 9 linear, the grooves are provided toward the outlet of the battery case, making it possible to dissipate heat efficiently.

[0029] The pressure for the press working in producing the metal foil-containing semi-cured resin fiber reinforced composite material intermediate is not particularly limited, and is usually 0.1 to 15 MPa.

[0030] [Press-molded member and manufacturing method thereof] The metal foil-containing semi-cured resin fiber reinforced composite material intermediates 1A, 1B and 1C obtained as described above are used to manufacture press molding members. The press-molding components may be made by using the metal foil-containing semi-cured resin fiber reinforced composite material intermediate materials 1A, 1B, and 1C as they are, or by layering the same or different types of prepregs on top of the metal foil-containing semi-cured resin fiber reinforced composite material intermediate materials 1A, 1B, and 1C to form press-molding components. When laminating another material such as prepreg onto the intermediate materials 1A, 1B, and 1C of the metal foil-containing semi-cured resin fiber reinforced composite material, it is preferable to simply laminate them without heating in order to maintain the semi-cured state. Since the semi-cured resin has adhesiveness, the materials can be bonded together without pressing. The press molding member is a material used in the hot press described below.

[0031] [Manufacturing method for pressed fiber-reinforced composite material components] The press molding member thus obtained is hot-pressed to produce a pressed fiber-reinforced composite material member 11A.

[0032] For example, as shown in Fig. 6(a), a press molding part according to the first embodiment (in the figure, a metal foil-containing semi-cured fiber reinforced composite intermediate material 1A is used as the press molding part) is placed in a press machine equipped with a lower die 10A and an upper die 10B. When molding a pressed fiber reinforced composite material part 11A into a box shape, it is preferable that the metal layer 2 is placed on the inside for efficient heat dissipation, so the metal layer 2 is placed so as to be in contact with the convex die. Specifically, in the case of Fig. 6, it is placed so as to be in contact with the lower die 10A.

[0033] Next, as shown in Fig. 6(b), the press molding member is pressed from above and below by the lower die 10A and the upper die 10B to deform it into a desired shape, and a pressed fiber-reinforced composite material molded member 11A is obtained. When applying pressure with the lower die 10A and the upper die 10B, the die is heated. The heating method can be, for example, providing a heater on one or both sides and heating it with the heater, blowing hot air onto it, or electromagnetic induction heating, but the heating method is not particularly limited. When pressing, the press-molding member can be pressed by moving the lower die 10A upward or by moving the upper die 10B downward.

[0034] The resin provided in the press molding member is in a semi-cured state, but it is preferable that the resin be cured through the above-mentioned hot pressing process.

[0035] Next, as shown in FIG. 6(c), the lower die 10A and the upper die 10B are removed from the molded metal composite 11A to obtain the molded metal composite 11A.

[0036] The pressed molded fiber-reinforced composite material part 11A processed into the desired shape as described above can be suitably used as a material or part for the housing of electronic devices such as battery cases, personal computers, office automation equipment, audio-visual equipment, mobile phones, telephones, facsimiles, home appliances, toys, and flat panel displays. This pressed fiber-reinforced composite material member 11A is lightweight and highly rigid after pressing, and is therefore particularly suitable for processing large vehicle-mounted battery cases as shown in Fig. 7. There are no particular limitations on the shapes of the housing and the battery case.

[0037] Furthermore, when the metal foil 2 is processed into a box shape such as a battery case, it is preferable to have a shape in which the surface of the metal foil 2 faces inward in order to efficiently release internal heat as shown in Fig. 7. Furthermore, in order to provide the grooves 9, the metal foil 2 may be press molded using only the metal foil 2. A plurality of linear grooves 9 may be provided, and the linear grooves 9 may be parallel to each other. In the heated fiber-reinforced composite pressed molded member 11A, the grooves 9 are relatively prone to retaining heat, and the heat can be guided in the desired direction to release the heat depending on the arrangement direction of the grooves 9. [Explanation of symbols]

[0038] 1A: Semi-cured fiber-reinforced resin composite material intermediate according to the first aspect of the present invention 1B: Semi-cured fiber-reinforced resin composite material intermediate according to the second aspect of the present invention 1C: Semi-cured fiber-reinforced composite material intermediate according to the third aspect of the present invention 2. Metal foil 3. Adhesive sheet 4. Textiles and fabrics 5. Semi-cured resin sheet 7. Filled saturated or unsaturated polyester resins 8. Double belt device 9...Groove 10A...Lower mold 10B...upper mold 11A...Pre-pressed fiber-reinforced composite material

Claims

1. A press molding member comprising an intermediate material for a metal foil-containing semi-cured fiber reinforced composite material in which at least two or more semi-cured resin sheets, a fiber fabric or unidirectional fibers, and a metal foil are laminated and integrated together.

2. The press-molding member according to claim 1 , wherein the resin of the semi-cured resin sheet is a thermosetting epoxy resin.

3. 2. The press-molding member according to claim 1, wherein the resin of the semi-cured resin sheet is a saturated or unsaturated polyester resin containing a filler.

4. The press-molded member according to claim 1 , wherein the metal foil has an adhesive sheet for adhering to the resin sheet.

5. The press-molded part according to claim 1 , wherein the metal foil has a surface provided with linear grooves.

6. The press-molding member according to claim 1 , wherein the woven fiber or the unidirectional fiber is glass fiber.

7. The press-molding member according to claim 1 , wherein the woven fiber or the unidirectional fiber is a carbon fiber.

8. A method for manufacturing a battery case, comprising a step of hot press molding the press molding material according to claim 1 , wherein the metal foil side is disposed on an inner side of the battery case.

9. 2. A method for producing a press-molding member, comprising: a step of integrating the intermediate material of the metal foil-containing semi-cured resin fiber reinforced composite material according to claim 1 by a double belt method.

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