Internal electrolyte supply system for reliable transport throughout

Abstract

An improved internal electrolyte supply system in a fuel cell stack employs a variety of arrangements of grooves and passages in bipolar plates of the multiplicity of repeating fuel cells to route gravity-assisted flowing electrolyte throughout the stack. The grooves route electrolyte flow along series of first paths which extend horizontally through the cells between the plates thereof. The passages route electrolyte flow along series of second paths which extend vertically through the stack so as to supply electrolyte to the first paths in order to expose the electrolyte to the matrices of the cells. Five different embodiments of the supply system are disclosed. Some embodiments employ wicks in the grooves for facilitating transfer of the electrolyte to the matrices as well as providing support for the matrices. Additionally, the passages of some embodiments by-pass certain of the grooves and supply electrolyte directly to other of the grooves. Some embodiments employ single grooves and others have dual grooves. Finally, in some embodiments the passages are connected to the grooves by a step which produces a cascading electrolyte flow.