PEM water electrolyser module

A method of producing hydrogen gas and oxygen gas using a PEM water electrolyser module comprising the steps of:

• (a) generating hydrogen gas and oxygen gas by electrolysis of water in a plurality of electrolytic cells contained in said PEM water electrolyser module;
• (b) transferring said hydrogen gas directly from the top part of each cathode half cell chamber to at least one hydrogen gas collection manifold integrally contained in said PEM water electrolyser module structure through respective hydrogen gas passages extending directly from said each cathode half cell chamber to said at least one hydrogen gas collection manifold;
• (c) removing said hydrogen gas from said at least one hydrogen gas collection manifold;
• (d) transferring a mixture of said oxygen gas and liquid water directly from the top part of each anode half cell chamber to a bottom part of at least one oxygen degassing chamber contained in said electrolyser module structure through respective gas-liquid passages extending directly from said each anode half cell chamber to said at least one oxygen degassing chamber;
• (e) separating said oxygen gas from said liquid water in said at least one oxygen degassing chamber to produce oxygen gas and degassed liquid water;
• (f) removing said oxygen gas from the top part of said at least one oxygen degassing chamber;
• (g) transferring said degassed liquid water directly from a bottom part of said at least one oxygen degassing chamber to the bottom part of each of said anode half cell chambers through respective discrete degassed liquid passages extending directly from said at least one oxygen degassing chamber to said each anode half cell chamber;
• and
• (h) wherein cooling is provided by cooling conduits in said oxygen degassing chamber.