H ELECTRICITY
H01 ELECTRIC ELEMENTS
H01M PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
H01M8/00 Fuel cells; Manufacture thereof
H01M8/04 Auxiliary arrangements, e.g. for control of pressure or for circulation of fluids
H01M8/04082 Arrangements for control of reactant parameters, e.g. pressure or concentration