TW201334978A - The strengthening method of flexible graphite composite - Google Patents

Abstract

The present invention relates to a strengthening method of flexible graphite composite, comprising the steps of performing high temperature treatment to powdered graphite to make it form vermicular graphite powder; pressing the vermicular graphite powder to form porous flexible graphite blank; performing glue seepage tot the graphite blank; performing drying treatment to the glued seeped graphite blank to remove the excess glue solvent in the flexible graphite blank; sandwiching a strengthening material between at least two flexible graphite blanks to form a multilayer structure; and then, performing hot press forming to the multilayer structure, so as to rapidly produce a large-sized and high conductive component of graphite composite plate, monopolar partition plate, and bipolar partition plate for fuel cell or vanadium battery use, thereby achieving objectives of mass production and reduction in manufacturing cost.

Description

Strengthening method of composite flexible graphite

The present invention relates to a method for strengthening flexible graphite, and more particularly to a method for strengthening composite flexible graphite which produces a multilayer structure.

A fuel cell is a device that directly uses hydrogen fuel and oxygen in the air to generate electricity and heat through an electrochemical reaction. Due to its low-pollution and high-efficiency clean power generation technology, it can be applied to generator sets, vehicle power and portable power. It has become the target of research and development and promotion in the United States, Japan and Europe in recent years.

Bipolar current collector-separator is an important component of fuel cell. The main function of bipolar separator is five: (1) as fuel gas (such as hydrogen H2) and oxidant (such as oxygen O2). Or air) gas partitioning plate, (2) having a gas guiding groove on both surfaces of the bipolar separator plate as a gas guiding groove, and (3) acting as a cathode and adjacent to another cell anode Current conduction, (4) as a current collector, (5) a coolant conduit can also be added inside the bipolar divider to remove battery heat.

It prevents the fuel gas (such as hydrogen) from mixing with the oxidant (such as oxygen), so it must have high gas impermeability and high electrical conductivity to the gas. Phosphoric acid fuel cells have acid corrosion problems, especially at high temperatures, so it is particularly difficult to develop bipolar separator plates. Currently, the bipolar separator plates of phosphoric acid fuel cells must withstand electrolytes operating at temperatures up to about 205 ° C for a long time. corrosion. In addition, the bipolar separator must also have sufficient bending strength to withstand operating pressure and thermal cycling stability. It is also desirable in the design to make the bipolar separator plate as thin as possible, to make the battery smaller, and to improve electrical and thermal conductivity in order to achieve a more economical and diverse fuel cell.

Graphite material is a common material for fuel cell bipolar separators. Graphite materials include artificial graphite to be processed (such as Japan Toyo Carbon IG-15 graphite, US POCO graphite), carbon powder and thermoplastic polymer composite materials and toner. And thermosetting polymer composite materials. For example, U.S. Patent Nos. 4,301,222; 4,214,969; 4,197,178; 4,339,322; 4,214,969, et al.

However, the above materials often suffer from brittle, expensive, too heavy, difficult processing, low electrical conductivity, and high gas permeability. The price is too expensive to market a large number of commodities, and the brittleness of the material and the high gas permeability make the bipolar separator difficult to be as thin as possible, so that the fuel cell volume or the same volume can be reduced to obtain the maximum energy density.

US Patent No. 6,706,400 B2 Flexible grapbite article and method of manufacture, which adds ceramic fiber or graphite fiber to worm-like graphite to increase uniformity after rolling, flexible graphite after rolling forming, sprayed, dried and rolled The flow path is made into a graphite bipolar plate assembly. However, the invention adopts the method of impregnating flexible graphite by the spray-coating method, and the uniformity thereof is less easy to be uniformly controlled, especially when it is used as a large-area and large-thickness graphite bipolar plate assembly, so that the graphite bipolar plate is more difficult to be used. The component is delaminated when it is finally press-formed, and the flexible graphite is not added with any reinforcing material after molding, so the graphite bipolar plate assembly is relatively fragile.

Therefore, there is a great need in the industry to develop a method for strengthening flexible graphite, using a multi-layer structure of composite flexible graphite reinforcement method, so that the glue can have better uniformity in the flexible graphite and improve the process of the glue treatment, and avoid At the end of the press forming, delamination occurs, so that it can simultaneously produce cost and time effect, and effectively produce a composite flexible graphite component having a multi-layer structure with uniform size and large size.

In view of the above disadvantages of the prior art, the main object of the present invention is to provide a method for strengthening flexible graphite, integrating a porous flexible graphite initial embryo, a cementing treatment process, a drying treatment, a strengthening material, etc., to prepare uniformity. A high-strength composite flexible graphite component having a multi-layer structure.

In order to achieve the above object, according to one aspect of the present invention, a method for strengthening composite flexible graphite is provided, the method comprising: first providing a porous amorphous graphite initial embryo; and placing the porous flexible graphite primary embryo into a vacuum plasticizing The device is subjected to a osmosis treatment; the flexible graphite primordial after the osmosis is dried to remove excess osmotic solvent in the flexible graphite primordial; and a reinforcing material is sandwiched in at least two flexible graphite primaries a multilayer structure; the multilayer structure is subjected to a hot press forming process.

The porous flexible graphite primord can obtain the worm-like graphite powder by treating the expandable graphite powder at a high temperature, and then pressurizing the worm-like graphite powder to form the porous flexible graphite primord.

In the above step, the osmosis treatment comprises a bleed or vacuum bleed, and the glue may be a thermosetting resin such as polyamine, oxime resin, epoxy resin, phenolic resin, etc., and the weight of the thermosetting resin The ratio ranges below 90%.

The osmosis of the thermosetting resin comprises a osmotic solvent, and the osmotic solvent is to be excluded in the present invention. Therefore, the lytic solvent is subjected to a drying process, and the drying process may be a vacuumless drying method or a vacuum drying method. Solvent removal.

The above step includes using a reinforcing material, which may be selected from a metal mesh, a glass fiber cloth, a carbon or a graphite fiber cloth, etc., and the reinforcing material is used to insert at least two pieces of flexible graphite primaries to form a multilayer structure, Strengthen the strength of the multilayer structure. The multi-layer structure of the present invention may be a three-layer structure, two sheets of flexible graphite primaries on the outside, and a reinforcing material in the middle, and the reinforcing material may be glued or the reinforced material is first coated and then placed in at least two before being placed. Piece of flexible graphite in the embryo. In addition, the multilayer structure of the present invention can adjust the number of reinforcing materials and flexible graphite primordial layers as needed.

Finally, the multilayer structure is subjected to a hot press forming process, and the present invention utilizes hot pressing to form the multilayer structure. The hot press plate design may include a hot press process of a flow field runner or a flat plate, and the forming may be molded. The process is used to create the appearance of the multilayer structure.

The above summary, the following detailed description and the accompanying drawings are intended to further illustrate the manner, the Other objects and advantages of the present invention will be described in the following description and drawings.

The embodiments of the present invention are described below by way of specific examples, and those skilled in the art can readily appreciate other advantages and functions of the present invention from the disclosure herein.

Please refer to the first figure, which is a schematic diagram of the steps of a method for strengthening a composite flexible graphite according to the present invention. As shown in the figure, the steps include:

Step 1: Providing expandable powdery graphite, and subjecting the powdered graphite to a high temperature treatment, the powdery graphite is formed into a worm-like graphite powder.

Step 2: Pressing the worm-like graphite powder to form a multi-porous flexible graphite primordial.

Step 3: The flexible graphite primordial and the reinforcing material are placed in a vacuum osmosis device for osmosis treatment.

Step 4: The flexible graphite primordial and the reinforcing material after the nitriding are placed in a drying device for drying, the flexible graphite primordial and the reinforcing material solvent are dried, and the solvent is recovered and reused.

Step 5: The reinforcing material is sandwiched between two sheets of flexible graphite primaries to form a three-layer structure, and then the three-layer structure is subjected to hot press forming. The reinforcing material may be glue-free or pre-coated, and the reinforcing material may be a metal mesh, such as 316 stainless steel mesh, glass fiber cloth, carbon or graphite fiber cloth, etc., thereby obtaining a rapid production of high conductivity, fuel cell or vanadium battery, etc. Components such as graphite composite plates, monopolar separator plates and bipolar separator plates further achieve mass production and reduce manufacturing costs.

To further illustrate the invention, it is illustrated by the examples.

Example:

The expandable graphite powder is transformed into a worm-like graphite powder by high-temperature heat treatment, and 10 g of a worm-like graphite powder material is pre-compressed to extrude a 20 cm x 40 cm x 0.66 cm size and have a porous flexible graphite primordial. The flexible graphite primary embryo and the 316 stainless steel mesh are placed in a vacuum infiltration device, vacuumed, and then injected with epoxy resin. The epoxy resin type 507, 906 and the catalyst Dy061 are uniformly mixed at a fixed ratio of 100:80:1. Epoxy resin is diluted with acetone solvent, epoxy resin: acetone solvent ratio is 1:4. After the solution was removed, the gelled virgin embryos were dried at 65 ° C for 8 hours, followed by vacuum treatment at 90 ° C for 5 hours. The flexible graphite primordial is subjected to hot press forming at 130 ° C and pressure of 70 kg/cm 2 , and the flat test piece can be pressed, or the flow field flow path hot press plate can be simultaneously designed to press out the flow field on the surface of the composite flexible graphite material. The test piece 9.4mmx2.9mmx60mm measured density was 1.55g/cm3 and the volume resistivity measured by AX-124N, 1KHz, mΩ low resistance was 6.8x10-4Ω-cm. The measured density was 1.91 g/cm 3 and the volume resistivity was 7.9 x 10 -4 Ω-cm with respect to the Japanese IG15 graphite test piece of 10 mm x 5 mm x 60 mm.

The process technology features of this embodiment are different from the previous ones. For example, this case has quite different points from the US patent US 6,706,400 B2. For the difference, please refer to Table 1.

The high-strength composite flexible graphite component having the multi-layer structure prepared in this embodiment has the strength to meet the needs of the current high-power fuel cell, and the electrode plate of the vanadium battery and the like requires a large size of about 1 mx1 m plate. High-strength design can meet the large-scale process conditions to improve the yield of large-area electrode plates

The above-described embodiments are merely illustrative of the features and functions of the present invention, and are not intended to limit the scope of the technical scope of the present invention. Modifications and variations of the above-described embodiments can be made by those skilled in the art without departing from the spirit and scope of the invention. Therefore, the scope of protection of the present invention should be as set forth in the scope of the claims described below.

S101-S105. . . step

The first figure is a schematic diagram of the steps of an embodiment of a method for strengthening composite flexible graphite according to the present invention.

S101-S105. . . step

Claims (10)

A method for strengthening composite flexible graphite, the method comprising: providing a porous amorphous graphite initial embryo; placing the porous flexible graphite primary embryo into a vacuum infiltration device for performing a cementing treatment; and initializing the flexible graphite after the cementing The embryo is dried to remove excess osmotic solvent in the flexible graphite primordial; a reinforcing material is sandwiched in at least two sheets of flexible graphite primaries to form a multilayer structure; and the multilayer structure is subjected to a hot press forming process . The method for strengthening composite flexible graphite according to claim 1, wherein the worm-like graphite powder is obtained by treating the expandable graphite powder at a high temperature, and then the worm-like graphite powder is pressurized to form a process. Porous flexible graphite primordial. The method for strengthening composite flexible graphite according to claim 1, wherein the osmosis treatment comprises a bleed or vacuum bleed. The method for reinforcing composite flexible graphite according to claim 3, wherein the adhesive is a thermosetting resin. One of polyamidoamine, oxime resin, epoxy resin, and phenolic resin. The method for reinforcing composite flexible graphite according to claim 4, wherein the thermosetting resin is selected from the group consisting of polyamidoamines, oxime resins, epoxy resins, and phenolic resins having a resin weight ratio of less than 90%. One. The method for strengthening composite flexible graphite according to claim 1, wherein the drying treatment is performed by vacuum drying or vacuum drying. The method for reinforcing composite flexible graphite according to claim 1, wherein the reinforcing material is one selected from the group consisting of metal mesh, glass fiber cloth, carbon or graphite fiber cloth. The method for reinforcing composite flexible graphite according to claim 1, wherein the multilayer structural system is a three-layer structure. The method for reinforcing a composite flexible graphite according to claim 1, wherein the hot press plate design of the hot press forming process comprises a flow field runner or a flat plate design. The method for reinforcing composite flexible graphite according to claim 8, wherein the multilayer structure can be hot pressed according to the need to adjust the number of reinforcing materials and the number of layers of flexible graphite.