Electrolyte circulation in fuel cells stacks with reduced leakage current

Abstract

A fuel cell stack () comprises a plurality of fuel cells each with a chamber (K) for electrolyte with at least one inlet () and at least one outlet (), and an inlet header () to supply electrolyte to all the cells in parallel. Each cell comprises a first plate () to define the electrolyte chamber (K), a second plate () to define an oxidizing gas chamber () and a third plate () to define a fuel gas chamber (H), each of these plates (-) also defining a side chamber () adjacent to but sealed from the corresponding chambers (K,, H), so the side chambers () defines an electrolyte outlet channel. An electrolyte flow channel () is also defined above the top portion of and in communication with the electrolyte chamber (K), so electrolyte is supplied from electrolyte supply () through openings () into the electrolyte chamber (K), flows upwards towards the top of the electrolyte chamber (K), exits said electrolyte chamber (K) via grooves (), flows along the flow channel (), breaks up into droplets at lip () and falls into the side chamber () prior to being expelled via electrolyte outlet (). This arrangement reduces leakage currents.