CN106738999A - A kind of polyaxial carbon fibre composite car battery box and its manufacture method - Google Patents

Abstract

The invention belongs to the technical field of auto parts, and relates to a multi-axial carbon fiber composite car battery box, which is made of multi-axial carbon fiber warp-knitted fabric prepared by a multi-axial warp knitting process as a reinforcing material, and epoxy Resin is a composite material of the base material; the multiaxial carbon fiber warp-knitted fabric includes eight layers of parallel layups arranged in sequence, and the layup angles of the layups are 0°, 45°, 90° and -45°, Each ply angle has two plies. Using 8-layer carbon fiber multi-axial warp knitted fabric as fiber reinforcement material, the prepared battery box is 50% lighter than traditional steel or high-density plastic battery boxes. The weaving process can realize mechanized overall molding, which is more efficient than the cumbersome layer-by-layer laying process of ordinary laminated structures; it has more stable structural properties than laminated boards, and while ensuring excellent mechanical properties along the direction of fiber reinforcement, It is not easy to appear delamination phenomenon, and the performance between layers is better.

Description

A kind of multi-axial carbon fiber composite car battery box and its manufacturing method

technical field

The invention belongs to the technical field of automobile parts, and in particular relates to a multiaxial carbon fiber composite automobile battery box and a manufacturing method thereof.

Background technique

As an important direction of the current and future development of automobiles, automobile lightweight has attracted more and more attention from designers. One of the important ways of automobile lightweight is to use lightweight materials. Carbon fiber composite materials have excellent mechanical properties and low density, and are gradually replacing steel and widely used in the automotive industry. In terms of the application of automobile battery boxes, CN105014988 discloses a carbon fiber automobile battery box and a manufacturing method of a carbon fiber automobile battery box. Carbon fiber laminated structural composite materials are used to replace steel materials, and while meeting the rigidity and strength requirements, the battery box is reduced. the quality of. CN104827680 discloses a protective casing for an on-board battery of an electric vehicle and a preparation method thereof. While replacing steel materials with carbon fiber laminated structural composite materials, multi-directional laminates are used on the laminate to protect the battery. It will not affect the lightweight of the car.

However, due to the cumbersome laying process of the fiber laminated structure, if the battery box is all made of carbon fiber laminated structural composite materials, the preparation time will be greatly prolonged, reducing production efficiency, and the interlayer performance of the fiber laminated structural composite material is slightly insufficient.

Contents of the invention

In order to solve the defect of the cumbersome layering process of the carbon fiber laminated structure existing in the prior art, the present invention provides a multiaxial carbon fiber composite material automobile battery box and a manufacturing method thereof.

In order to solve the above technical problems, the technical solution adopted in the present invention is: a multi-axial carbon fiber composite car battery box, the material of which is a multi-axial carbon fiber warp-knitted fabric prepared by a multi-axial warp knitting process as a reinforcing material , a composite material based on epoxy resin;

The multi-axial carbon fiber warp-knitted fabric comprises eight layers of parallel plies arranged in sequence, and the ply angles of the plies are 0°, 45°, 90° and -45°, and each ply angle has two layup.

Specifically, the carbon fiber is T300-3k carbon fiber, the tensile modulus is 230GPa, and the tensile strength is 3.53GPa, and the epoxy resin is NPEL-128 epoxy resin.

Preferably, the volume ratio of the reinforcing material to the base material is 1:1.

The method for manufacturing the above-mentioned multi-axial carbon fiber composite car battery box is characterized in that it includes the following steps:

(1) Mold pretreatment: Wipe the surface of the mold with a release agent to facilitate demoulding;

(2) Fabric laying: Lay the multi-axial carbon fiber warp-knitted fabric in the mold cavity evenly according to the laying angle, so as not to wrinkle it, and trim off the excess scrap;

(3) Mold closing: close the upper mold and the lower mold, and seal and fasten the periphery;

(4) Resin injection: Mix epoxy resin and curing agent evenly, and then inject from the mold inlet to fully infiltrate the multi-axial carbon fiber warp knitted fabric;

(5) Curing: the mold is placed in a heating furnace for temperature-controlled curing;

(6) Demoulding: Separate the upper and lower molds, separate the battery box from the mold and check whether the product is defective;

(7) Post-processing: Clean the mold and injection equipment with a mold cleaner.

Further, step (1) wipe the surface of the mold with a demoulding machine for more than 3 times, with an interval of 15-20 minutes each time, and wipe in one direction.

Preferably, the mass ratio of the epoxy resin and the curing agent in step (4) is 1:0.005-0.1, and the epoxy resin and the curing agent are mixed uniformly, and left to stand for 20-30 minutes.

Further, it is characterized in that: in step (4), the injection pressure for injecting epoxy resin and curing agent from the injection port of the mold is 0.1-0.2 MPa, and the injection is stopped until no air bubbles appear at the injection port.

Preferably, the temperature-controlled curing conditions described in step (5) are as follows: a temperature of 40-50° C., and a curing time of 1.5-2 hours.

Preferably, the mold cleaning agent described in step (7) is acetone.

Beneficial effects: 1. The multi-axial carbon fiber composite car battery box provided by the present invention adopts 8 layers of carbon fiber multi-axial warp-knitted fabric as the fiber reinforcement material, and epoxy resin as the matrix. The prepared battery box is compared with traditional steel Or a high-density plastic battery box with 50% less mass.

2. The multi-axial carbon fiber composite car battery box provided by the present invention adopts a multi-axial warp weaving process, and the weaving process can realize mechanized integral molding. Compared with the cumbersome layer-by-layer laying process of ordinary laminated structures, the production efficiency is higher high;

3. The multi-axial warp knitted fabric provided by the present invention has more stable structural properties than laminated boards. Compared with ordinary laminated structure battery boxes, while ensuring excellent mechanical properties along the fiber reinforcement direction, delamination is not easy to occur. Interlayer performance is better.

4. The multi-axial carbon fiber composite car battery box provided by the present invention can adjust the laying angle and laying thickness of the reinforcing fibers arbitrarily according to the structural requirements of the battery box of different models, and has strong designability.

Description of drawings

Figure 1 is a schematic diagram of the three-dimensional structure of the battery box;

Figure 2 is a schematic diagram of the reverse structure of the battery box; in Figures 1 and 2, 1.1 is the bottom plate, 2.1 is the longitudinal rib, and 2.2 is the transverse rib.

Figure 3 is a schematic diagram of the structure of a multiaxial carbon fiber warp knitted fabric; in Figure 3, 3.1 is a 90° weft inlay yarn, 3.2 is a 45° weft inlay yarn, 3.3 is a -45° weft inlay yarn, 3.4 is a binding yarn, and 3.5 is a 0° warp inlay yarn.

Fig. 4 is the layup structure schematic diagram of embodiment 1 multiaxial carbon fiber warp knitted fabric; Among Fig. 4, 4.1 is 0 ° direction layup, 4.2 is 45° direction layup, 4.3 is -45° direction layup, 4.4 is 90° ° direction layup, 4.5 is 90° direction layup, 4.6 is -45° direction layup, 4.7 is 45° direction layup, 4.8 is 0° direction layup, 4.9 is binding yarn.

Fig. 5 is the layup structure schematic diagram of embodiment 2 multiaxial carbon fiber warp knitted fabrics; Among Fig. 5, 5.1 is 0 ° direction layup, 5.2 is 90° direction layup, 5.3 is -45° direction layup, 5.4 is 45° ° direction laying, 5.5 is laying in 45° direction, 5.6 is laying in -45° direction, 5.7 is laying in 90° direction, 5.8 is laying in 0° direction, and 5.9 is binding yarn.

Fig. 6 is the schematic diagram of embodiment 3 lamination structure fabric structure; Among Fig. 6, 6.1 is 0 ° direction lay-up, 6.2 is 90 ° direction lay-up, 6.3 is-45 ° direction lay-up, 6.4 is 45 ° direction lay-up, 6.5 Lay in the direction of 45°, 6.6 in the direction of -45°, 6.7 in the direction of 90°, and 6.8 in the direction of 0°.

Figure 7 is a schematic diagram of the RTM system structure; in Figure 7, 7.1 is the air compressor, 7.2 is the injection molding machine, 7.31 is the fixing bolt, 7.32 is the injection port, 7.33 is the upper mold, 7.34 is the glue outlet, 7.35 is the lower mold, 7.4 It is a multi-axial mixed fiber warp knitted fabric, and 7.5 is a resin receiving bucket.

detailed description

In order to make the purpose, technical solution and advantages of the present invention clearer, further detailed description will be given below in conjunction with examples.

Example 1

In the first aspect, this example provides a multi-axial carbon fiber composite car battery box (structure as shown in Figure 1 and Figure 2, including a bottom plate 1.1, a longitudinal rib 2.1 and a transverse rib 2.2 arranged at the bottom of the bottom plate 1.1) , using the multi-axial warp knitting process, carbon fiber is used as a reinforcing material to prepare a multi-axial warp knitted fabric. Through RTM injection molding technology, the resin is soaked into the multi-axial warp knitted fabric and then formed. The layup has 8 layers, and the matrix Use epoxy.

In the composite car battery box provided by the example of the present invention, the reinforcing material adopts a multi-axial warp-knitted structure, and the structural form is shown in FIG. 3 . The multi-axial warp knitting structure includes 90° weft inlay yarn 3.1, 45° weft inlay yarn 3.2, -45° weft inlay yarn 3.3, binding yarn 3.4, and 0° warp inlay yarn 3.5.

Compared with ordinary single-fiber-reinforced laminates, the multiaxial warp-knitted fabric has a more stable structure, better mechanical properties, and stronger designability. The specific performance is as follows:

(1) The fibers in the multi-axial warp knitted fabric are distributed straight, so that the performance in the main direction of the fabric fibers can be fully exerted;

(2) Multi-axial warp knitted fabrics introduce bundled yarns, which have better interlayer performance and better overall structural performance than laminated structures;

Specifically, standard layup angles are selected for the layup: 0°, 45°, 90°, -45°, and the layup sequence is [0,45,-45,90] _{S, and the} specific structure is shown in Figure 4: From top to bottom, the first layer is layer 4.1 at 0°, the second layer is layer 4.2 at 45°, the third layer is layer 4.3 at -45°, the fourth layer is layer 4.4 at 90°, and the fifth layer 4.5 layers in 90° direction, 4.6 layers in -45° direction for the sixth layer, 4.7 layers in 45° direction for the seventh layer, 4.8 layers in 0° direction for the eighth layer, and 4.9 bundled yarns.

The second aspect of this example provides a method for manufacturing a multi-axial carbon fiber composite car battery box. The process principle is shown in Figure 7, including the following steps:

Step (1) Preparation

1.1) Multi-axial carbon fiber warp-knitted fabric; using the multi-axial warp-knitting process, the carbon fiber reinforced material is woven into the required multi-axial carbon fiber warp-knitted fabric according to the design angle and layup sequence.

1.2) Preparation of the mold; carefully check whether the mold is damaged and whether there are sundries inside

1.3) RTM molding equipment; check RTM injection equipment 7.2, prepare curing agent, release agent, air compressor 7.1 and other related accessories.

Step (2) Mold pretreatment

Wipe the inner surface of the mold with the mold release agent 4 times, moisten the mold gently in one direction, do not wipe back and forth, and wipe every 15 minutes.

Step (3) Fabric laying

Lay the multi-axial carbon fiber warp knitted fabric 7.4 woven according to the design requirements evenly in the mold cavity without wrinkling, and trim off excess scrap.

Step (4) Mold closing

The upper mold 7.33 and the lower mold 7.35 are closed, and the periphery is sealed and fastened by fixing bolts 7.31.

Step (5) Resin Injection

5.1) The epoxy resin and curing agent are mixed according to the ratio of 1:0.05, and the experimental environment temperature is 25°C to ensure that the resin has good fluidity and wettability during the injection process.

5.2) Stir the epoxy resin and curing agent evenly, let it stand for 25 minutes, and remove the air in the mixed resin glue.

5.3) Set the air compressor 7.1 to ensure that the injection pressure is 0.15MPa, and inject the resin into the mold from the injection port 7.32. During the injection process, resin and air bubbles can be observed at the injection port 7.34; Bubbles appear, the glue fully infiltrates the fabric, the glue injection is stopped, and the resin coming out of the glue outlet 7.34 is collected by the resin receiving barrel 7.5.

Step (6) curing

The mold is placed in a heating furnace for temperature-controlled curing, the curing temperature is controlled at 40° C., and the curing time is 2 hours.

Step (7) demoulding

After the mold is cooled, the upper and lower molds are separated, the battery box is separated from the mold, and the product is inspected for defects.

Step (8) post-processing

Clean the mold and RTM dispensing equipment with acetone.

Example 2

The shape, material and preparation method of the automobile battery box provided in this example are basically the same as in Example 1, the difference lies in the layering of the multiaxial warp-knitted fabric, and the layering angle is [0,90,-45,45] _S , specifically The structure is shown in Figure 5: the first layer is 5.1 in the 0° direction, the second layer is 5.2 in the 90° direction, the third layer is 5.3 in the -45° direction, the fourth layer is 5.4 in the 45° direction, and the fifth layer is in the 45° direction. Lay 5.5 in the 45° direction of the first layer, 5.6 in the sixth layer in the -45° direction, 5.7 in the 90° direction of the seventh layer, and 5.8 in the 0° direction of the eighth layer.

Example 3

This example is used as a comparison. The shape and preparation method of the car battery box provided are basically the same as those in Example 1. The difference lies in the selection of pure carbon fiber laminated structure fabrics. Going up, the specific laying angle is [0,90,-45,45] _S , and the specific structure is shown in Figure 6: the first layer is 6.1 in the direction of 0°, the second layer is 6.2 in the direction of 90°, and the third layer Lay 6.3 in the -45° direction, 6.4 in the 45° direction of the fourth layer, 6.5 in the 45° direction of the fifth layer, 6.6 in the -45° direction of the sixth layer, 6.7 in the 90° direction of the seventh layer, 6.7 in the 90° direction of the seventh layer Lay 6.8 in eight layers in 0° direction.

The weight and rigidity of the battery case provided by Example 1, Example 2 and Example 3 and pure metal were tested respectively. A battery mass of 128 kg is applied at the center of gravity of the battery box provided in each example, and the z-direction displacement of the battery box is measured.

The test results are shown in Table 1:

Through the comparison of Table 1, it is found that the two embodiments of the multi-axial carbon fiber composite car battery box provided by the embodiment of the present invention have relatively high rigidity, which can ensure the safety of the battery when the car is running normally. Compared with the metal battery box, the total mass of the multi-axial carbon fiber composite car battery box is reduced by 50% because of the low density of the fiber composite material. Compared with the pure carbon fiber laminated composite material battery box, the multi-axial warp knitting process makes the interlayer performance better, and the multi-axial warp knitting process is simple to lay up layers, which is convenient for mechanization and higher production efficiency. In summary, the multi-axial carbon fiber composite car battery box proposed by the present invention has the characteristics of light weight, high strength, high performance, and high efficiency.

Claims (9)

1. A multi-axial carbon fiber composite car battery box, characterized in that: its material is to utilize the multi-axial carbon fiber warp knitting fabric prepared by the multi-axial warp knitting process as a reinforcing material, and epoxy resin as a base material composite materials; The multi-axial carbon fiber warp-knitted fabric comprises eight layers of parallel plies arranged in sequence, and the ply angles of the plies are 0°, 45°, 90° and -45°, and each ply angle has two layup. 2. The multi-axial carbon fiber composite car battery box according to claim 1, characterized in that: the carbon fiber is T300-3k carbon fiber, the tensile modulus is 230GPa, the tensile strength is 3.53GPa, and the epoxy resin It is NPEL-128 epoxy resin. 3. The multi-axial carbon fiber composite car battery box according to claim 1 or 2, characterized in that: the volume ratio of the reinforcing material to the base material is 1:1. 4. The method for manufacturing a multi-axial carbon fiber composite car battery box according to any one of claims 1 to 3, characterized in that it comprises the following steps: (1) Mold pretreatment: Wipe the surface of the mold with a release agent to facilitate demoulding; (2) Fabric laying: Lay the multi-axial carbon fiber warp-knitted fabric in the mold cavity evenly according to the laying angle, so as not to wrinkle it, and trim off the excess scrap; (3) Mold closing: close the upper mold and the lower mold, and seal and fasten the periphery; (4) Resin injection: Mix epoxy resin and curing agent evenly, and then inject from the mold inlet to fully infiltrate the multi-axial carbon fiber warp knitted fabric; (5) Curing: the mold is placed in a heating furnace for temperature-controlled curing; (6) Demoulding: Separate the upper and lower molds, separate the battery box from the mold and check whether the product is defective; (7) Post-processing: Clean the mold and injection equipment with a mold cleaner. 5. The manufacturing method of multi-axial carbon fiber composite car battery case according to claim 4, characterized in that: step (1) wipe the surface of the mold with a demoulding machine for more than 3 times, each interval is 15-20min, and Wipe in one direction. 6. The method for manufacturing a multi-axial carbon fiber composite car battery box according to claim 4, characterized in that the mass ratio of the epoxy resin to the curing agent in step (4) is 1:0.005-0.1, and the ring After the epoxy resin and curing agent are mixed evenly, let it stand for 20-30 minutes. 7. The manufacturing method of the multi-axial carbon fiber composite car battery box according to claim 4 or 6, characterized in that: in the step (4), the injection pressure of injecting epoxy resin and curing agent from the injection port of the mold is 0.1 ~ 0.2MPa, inject glue until no air bubbles appear at the glue outlet, stop injecting glue. 8. The method for manufacturing a multi-axial carbon fiber composite car battery box according to claim 4, characterized in that: the temperature-controlled curing conditions described in step (5) are as follows: a temperature of 40-50°C, and a curing time of 1.5-50°C. 2h. 9. The method for manufacturing a multi-axial carbon fiber composite car battery box according to claim 4, characterized in that the mold cleaner in step (7) is acetone.