Assertion: fuel cell | /r/HasProperty | stacked
Facets:
value: together
type: MANNER
value: mainly
type: DEGREE
Source sentences:
text: Fuel cells are stacked to increase voltage.
text: The fuel cell was a stack design that allowed the fuel cell to be integrated with the plane's aerodynamic surfaces.
text: Fuel cells are designed to be flat and thin, mainly so they can be stacked.
text: They are also modular, meaning they can be stacked to generate various amounts of power as needed.
text: It sounds like the greatest thing since sliced bread except there are present limitations: A single fuel cell produces just a fraction of a volt, so many fuel cells must be stacked together to produce the desired amount of electricity; The output of the fuel cell is directly proportional to the purity of the hydrogen.