A polymer electrolyte membrane (or proton exchange membrane) is a specially treated fluoropolymer material at the heart of certain fuel cells and electrolyzers. It allows positively charged protons to pass through from the anode to the cathode while forcing electrons to travel through an external circuit, generating an electric current. The membrane must be kept hydrated to function and degrades if exposed to excessive heat or impurities.
The stack failed the pressure test, so we likely have a ruptured PEM on cell forty-two.
PEM can stand for either polymer electrolyte membrane or proton exchange membrane, but in the shop, both refer to the exact same Nafion-style material.
Related terms
Fuel cell
An electrochemical device that continuously converts the chemical energy of a fuel and an oxidant directly into electrical energy.
Reformer
A refining unit that converts low-octane naphtha into high-octane reformate.
Synthesis gas
A fuel gas mixture consisting primarily of hydrogen, carbon monoxide, and some carbon dioxide.