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Molding preparation method of fuel cell bipolar plate

A fuel cell and bipolar plate technology, applied in fuel cells, circuits, electrical components, etc., can solve the problems of long production cycle, uneven particle size and irregular shape of expanded graphite, achieve short molding time and improve uniformity Effect

Active Publication Date: 2019-06-28
TSINGHUA UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The disadvantage is that the production cycle is long, and it takes 15 to 20 minutes to manufacture a bipolar plate, and the molded plate prepared by this process is thicker, with the thinnest thickness exceeding 2mm, which can reduce the thickness of the bipolar plate to increase the specific power of the stack to a limited extent
For plate molding, the general molding object is prefabricated expanded graphite plate. Expanded graphite is generally prepared from natural flake graphite through intercalation, washing, drying, and high-temperature expansion. It has a loose and porous structure, but at the same time, the particle size of expanded graphite is not uniform. , Irregular shape, sharp edges and corners, after molding, there will be defects with large local gaps. Although there is a dipping process, this uneven dipping will affect the airtightness of the bipolar plate on the one hand, and on the other. On the one hand, it also brings a lot of uncertainty to the area resistance and long-term reliability of the bipolar plate
In addition, at present, conventional molding techniques are generally used for the molding of composite plates, such as stamping or rolling technology. The bipolar plates prepared by this conventional technology have great advantages in terms of density uniformity and plate structure constraints. defect

Method used

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  • Molding preparation method of fuel cell bipolar plate

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Experimental program
Comparison scheme
Effect test

Embodiment 1

[0029] 1) Take 2000g of expanded graphite, and use a graphite shaping machine to carry out shaping treatment on it. The shaping time is 10 minutes. After shaping, the long diameter of the expanded graphite is reduced by about 40%;

[0030] 2) Take 150g of shaped expanded graphite and place it in the mold of the isostatic pressing equipment. Under the pressure of 200MPa and normal temperature, the pressing process is completed within 2 minutes to obtain a 0.9mm thick bipolar plate with a flow field;

[0031] 3) Take out the pressed bipolar plate and place it in the dipping device, then vacuumize the dipping device, and then inject a certain amount of polyimide resin into it, and the resin completely immerses the bipolar plate, Under these conditions, soak the glue for 12h. During this process, vacuuming is repeated 2-3 times to ensure that the vacuum degree of the dipping process is less than 1 atmosphere.

[0032] 4) Take out the dipped bipolar plate, and then rinse it with a...

Embodiment 2

[0035]1) Take 1000g of expanded graphite, and use a graphite shaping machine to shape it. The shaping time is 5 minutes. After shaping, the long diameter of the expanded graphite is reduced by about 40%.

[0036] 2) Take 100g of reshaped expanded graphite and place it in the mold of the isostatic pressing equipment. Under the pressure of 100MPa and normal temperature, within 1min, the pressing process is completed to obtain a 0.6mm thick bipolar plate with a flow field.

[0037] 3) Take out the pressed bipolar plate and place it in the dipping device. Then, the dipping device is evacuated, and then a certain amount of acrylic resin is injected into it. The resin completely immerses the bipolar plate. Under this condition Next, dipping for 8h. During this process, vacuuming is repeated 2-3 times to ensure that the vacuum degree of the dipping process is less than 1 atmosphere.

[0038] 4) Take out the dipped bipolar plate, and then rinse it with deionized water.

[0039] 5) T...

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Abstract

The invention discloses a molding preparation method of a fuel cell bipolar plate, and the method belongs to the technical field of fuel cell component manufacturing. The method comprises the following steps of selecting expanded graphite, shaping the expanded graphite, placing the shaped expanded graphite into a mold of an isostatic pressing device to press the expanded graphite to obtain a bipolar plate with a flow field, and performing dipping in resin, rinsing and hot water curing or dry curing to obtain the bipolar plate. According to the method, the uniformity of a gap of the bipolar plate after molding and the uniformity of the density of a molded plate are improved, the density uniformity is within + / -1%, and the bipolar plate can be as thin as 0.5 mm. Furthermore, the uniformity of the resistance of different regions of the bipolar plate is improved. At the same time, the bipolar plate is prepared by isostatic pressing at room temperature, no additional release agent is needed, the molding time is short, and the bipolar plate is suitable for mass production.

Description

technical field [0001] The invention belongs to the technical field of manufacturing fuel cell components, and in particular relates to a method for molding a bipolar plate of a fuel cell. Background technique [0002] Fuel cell is a kind of energy conversion device, which converts the chemical energy stored in fuel and oxidant directly into electrical energy according to the electrochemical principle. It has the advantages of high power generation efficiency and less environmental pollution, and has a wide application prospect. Among them, the bipolar plate is one of the core components of the fuel cell. Its main function is to separate the reactant gas and introduce the reactant gas into the fuel cell through the flow field, collect and conduct current, support the membrane electrode, and also undertake the heat dissipation and drainage of the entire fuel cell. Function. [0003] At present, the bipolar plates used in fuel cells mainly include graphite, metal and composit...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M8/0245H01M8/0234H01M8/0239
CPCY02E60/50Y02P70/50
Inventor 王诚雷一杰唐亚平
Owner TSINGHUA UNIV
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