Apparatus for supplying electrolyte to fuel cell stacks

Abstract

Apparatus for use with existing electrolyte passage means for replenishing electrolyte within the fuel cell stacks of a fuel cell stack module to keep the matrices in the optimum electrolyte-wetted condition. Pump means is provided to withdraw a predetermined volume of electrolyte from electrolyte reservoir means and propel it in a series of pulses of predetermined duration through transfer means to distribution means which divides the electrolyte volume into streams according to the number of fuel cell stacks in the module. Each portion of the electrolyte volume is then introduced into existing electrolyte passage means. The pulses of electrolyte must be of a sufficiently short duration that no electrolyte streams are still issuing within distribution means when electrolyte has reached electrolyte passage means of the fuel cell stacks. If the streams are still issuing at this time, a circuit will be completed between the fuel cell stacks through the electrically conductive electrolyte, damaging the stacks. Gravity assists the electrolyte through electrolyte passage means within the fuel cell stacks. Drainage means conveys electrolyte not absorbed by the fuel cell matrices to electrolyte reservoir means for recirculation. Electrolyte reservoir means may comprise a tank positioned within the fuel cell stack module or an external tank. Filtration means may be employed to prevent recirculation of debris and corrosion products. The apparatus works equally well with a basic electrolyte as it does with an acid electrolyte. Vent means may be employed to pressure balance the apparatus.