Fuel cell stack&Membrane electrode assembly

A fuel cell stack is a combination of two or more single cells and other necessary structural components, with a unified electrical output. The necessary structural components include: electrode plates, collector plates, end plates, seals, etc. Figure 2-1 shows a cross-sectional schematic diagram of the fuel cell stack. The structure of the fuel cell stack can be represented by alternating layers of bipolar plates and membrane electrodes, and sealing elements are embedded between each unit for fluid sealing and external sealing. The end of the fuel cell stack is equipped with a collecting plate for current output, which is compressed by the front and rear plates and fixed with screws or straps to form a fuel cell stack. The actual 70kW fuel cell stack is shown in Figure 2-2. When the PEMFC stack is running, it first introduces fuel (mainly hydrogen or methanol) and oxidants (oxygen, air) from the inlet, and then enters the double plate through the stack electrode and open electrode manifolds. Both are distributed in the anode and cathode catalytic layers of the membrane electrode assembly, and finally undergoes electrochemical reactions under the action of the catalyst. During the operation of the stack, a large amount of heat is generated, so the temperature of the stack must be controlled by adding a refrigerant (such as cooling water), with the refrigerant flow channel located in the middle of the bipolar plate.

Figure: Cross section schematic diagram of fuel cell stack

Figure: Physical object of 70kW fuel cell stack