A bipolar plate, an important component of the fuel cell
Bipolar plates
Bipolar plates are made of graphite or metal; they evenly distribute the fuel and the oxidant to the cells of the fuel cell. They also collect the generated electric current at the output terminals.
In a single-cell fuel cell, there is no bipolar plate; however, there is a single-sided plate that provides the flow of electrons. In fuel cells that have more than one cell, there is at least one bipolar plate (flow control exists on both sides of the plate). Bipolar plates provide several functions in the fuel cell.
Some of these functions include the distribution of fuel and oxidant inside the cells, the separation of the different cells, the collection of the electric current produced, the evacuation of the water from each cell, the humidification of the gases and cooling of the cells. Bipolar plates also have channels which allow the passage of reactants (fuel and oxidant) on each side. They form the anode and cathode compartments on opposite sides of the bipolar plate. The design of the flow channels may vary; they may be linear, coiled, parallel, comb-like or evenly spaced as shown in below photo.
The different types of bipolar plate [COL 08]. a) Coiled flow channels; b) multiple coil flow channels; c) parallel flow channels; d) interdigitated flow channels
The materials are chosen based on chemical compatibility, corrosion resistance, cost, electrical conductivity, gas diffusion ability, impermeability, ease of machining, mechanical strength and their thermal conductivity.
Post time: Jun-24-2021