Abstract: An illustrative example fuel cell device includes a cell stack assembly of a plurality of fuel cells that each include an anode and a cathode. A pressure plate is situated near one end of the cell stack assembly. A spacer between the end of the cell stack assembly and the pressure plate has a length, a width, and a height. The height of the spacer defines a spacing between the pressure plate and the end of the cell stack assembly. The spacer has a plurality of ribs that define at least two fluid reservoirs. At least one of the ribs separates the fluid reservoirs so that fluid in one of the reservoirs is isolated from fluid in the other.