Preparation method of composite graphite bipolar plate

Abstract

The invention discloses a preparation method of a composite graphite bipolar plate. The preparation method comprises the following steps: by using graphite ore as a raw material, preparing expanded graphite at high temperature; mixing resin with an auxiliary conductive filler to obtain a first mixture; performing dry mixing on the expanded graphite and the first mixture to obtain a second mixture,and pressing the second mixture into a low-density prefabricated slab; carrying out mould pressing on the low-density prefabricated slab, and pressing a flow field on the upper surface or the upper and lower surfaces to manufacture a semi-finished monopole plate comprising a hydrogen flow field monopole plate and an oxygen flow field monopole plate; carrying out vacuum impregnation on the semi-finished monopole plate; and bonding the hydrogen flow field monopole plate and the oxygen flow field monopole plate by using a silk-screen printing technology through a bonding agent (mould pressing) to form a bipolar plate, and heating and curing to obtain the composite graphite bipolar plate. A compression molding process is adopted, so that the preparation method is more suitable for batch production, shortens the processing period and reduces the production cost; and the composite graphite bipolar plate is excellent in various performance indexes such as conductivity, density, air tightness, mechanical lightness and corrosion resistance.

Description

technical field

[0001] The invention relates to the technical field of fuel cells, in particular to a preparation method of a composite graphite bipolar plate. Background technique

[0002] Hydrogen fuel cell is a kind of proton exchange membrane fuel cell, which is equivalent to the "reverse" device of water electrolysis in principle. Its single cell is composed of bipolar plates and membrane electrodes. The voltage of a single battery is generally 0.3-1.0V, which is very low, so in practical applications, tens or hundreds of single batteries are used in series. Among them, the role of the bipolar plate mainly includes: providing the current path between adjacent single cells, the distribution channel of the reactant gas, the cooling channel, separating the fuel, coolant (water) and oxidant supplied to the single cell, and separating the adjacent cells. Fuel gas and oxidizing gas provide the mechanical strength necessary for the stability of the cell stack structure. [...

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