Several unit fuel cells are arranged in series into a so-called fuel cell stack to match voltage and power levels required in different applications. (From PowerCell Sweden AB) Such PEM-stacks are the building blocks of larger fuel cell systems. (From Nedstack Fuel Cell Technology BV)
Fuel Cell Stack – Image courtesy of Nedstack Fuel Cell Technology BV
A fuel cell stack is in itself a completely passive component which needs to be integrated into a fuel cell system to generate power. (From PowerCell Sweden AB)