Electrochemical fuel cell stack with concurrent flow of coolant and oxidant streams and countercurrent flow of fuel and oxidant streams

摘要

A fuel cell assembly within an electrochemical fuel cell stack has an anode layer and a cathode layer. A cooling layer is disposed adjacent the fuel cell assembly. Each layer comprises channels for directing a fluid stream from an inlet to a an outlet. The coolant stream channels extend such that, in operation, the coolest region of the cooling layer coincides with the region of the cathode layer having the highest concentration of oxygen (and/or the lowest water content), and the warmest region of the cooling layer coincides with the region of the cathode layer having the lowest concentration of oxygen (and/or the highest water content). The fuel stream channels extend such that, in operation, the fuel stream is directed to a region of the anode layer which coincides with the region of the cathode layer in which the oxidant stream has the lowest concentration of oxygen (and/or the highest water content) and is subsequently directed to a region of the anode layer which coincides with the region of the cathode layer in which the oxidant stream has the highest concentration of oxygen (and/or the lowest water content).