Metal plate single surface and graphite composite bipolar plate and preparation method

Abstract

The invention discloses a metal plate single surface and graphite composite bipolar plate. The bipolar plate comprises a hydrogen unipolar plate and an oxygen unipolar plate, wherein each unipolar plate is a composite unipolar plate formed by synthesizing a metal pole plate and graphite, a conducting layer is arranged on the surface of each metal pole plate, flexible graphite paper is pasted to one surface of each metal pole plate, and the pasting mode between the flexible graphite paper and each metal pole plate is breakpoint pasting. According to a preparation method, the flexible graphite paper is subject to the pretreatment of sealing internal micro-channels, planar base material plates are cut out, the conducting layers are formed on the surfaces of the planar base material plates, and the flexible graphite paper subject to the pretreatment is pasted to one surface of each planar base material plate; each planar base material plate with the graphite paper pasted to one surface ismold-pressed into one unipolar plate, and the hydrogen unipolar plate and the oxygen unipolar plate are connected in a sealed mode to form the bipolar plate. The bipolar plate has the advantages thatthe corrosion resistance of the bipolar plate is improved, and surface treatment cost of the metal bipolar plate is lowered.

Description

technical field [0001] The invention relates to the field of fuel cells, in particular to the bipolar plate technology of proton exchange membrane fuel cells. Background technique [0002] The bipolar plate of the proton exchange membrane fuel cell has the functions of separating hydrogen and oxygen, collecting current and supporting the membrane electrode, and making the battery system dissipate heat and drain water. Therefore, the bipolar plate material needs to have good corrosion resistance, good electrical conductivity, and good mechanical strength. , low price and easy batch processing and other characteristics. [0003] In the prior art, fuel cell bipolar plates are mainly made of graphite materials or metal materials. The prepared bipolar plates have their own advantages and disadvantages. Graphite materials are divided into two types: hard graphite and flexible graphite. Hard graphite bipolar plates are made by mechanical processing. , the processing cost is high, ...

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Problems solved by technology

[0003] In the prior art, fuel cell bipolar plates are mainly made of graphite materials or metal materials. The prepared bipolar plates have their own advantages and disadvantages. Graphite materials are divided into two types: hard graphite and flexible graphite. Hard graphite bipolar plates are made by mechanical processing. , the processing cost is high, and it is not suitable for mass production. Due to the hard and brittle material, the thickness of the finished bipolar plate should be 2mm to 3mm thick, resulting in a large fuel cell stack, but the advantages are good corrosion resistance and electrical conductivity; the flexible graphite bipolar plate is pressed It has good corrosion resistance and electrical conductivity, low material and processing costs, and is suitable for mass production. The disadvantages are that the mechanical strength is low, the finished bipolar plate is thick, and the assembled fuel cell stack is bulky; the metal material is used to prepare the bipolar plate. Metal sheet stamping and welding process, suitable for mass production, high mechanical strength, good electrical conductivity, can be made into a thin metal bipolar plate with a thickness of about 1mm, but the corrosion resistance is poor, the surface of the metal bipolar plate needs to be treated to establish a conductive and durable The corrosion layer, the conductive corrosion-resistant layer has two functions. The first function is to enhance the conductivity and reduce the contact resistance between the surface of the metal bipolar plate and the carbonaceous interface. The second function is to increase the corrosion resistance of the metal bipolar plate. To increase corrosion resistance, the conductive corrosion-resistant layer needs to have a certain thickness

To establish a conductive and corrosion-resistant layer, electroplating and physical vapor deposition are usually used. The electroplating method is to plate precious metals on the metal surface, such as silver, gold, and platinum, which can meet the requirements of electrical conductivity and corrosion resistance in the working environment of fuel cells, and the service life can also meet commercial requirements. Application requirements, but the price is expensive. Physical vapor deposition is sputtering carbon, carbide or nitride, or even boride, etc. on the metal surface. The main problem is that the expansion coefficient of the deposit is quite different from that of the metal plate. It is easy to fall off during the process, and the physical vapor deposition process takes a long time, so the cost is high

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