Master Bond EP29LPSP was cited in a patent issued to Plug Power Inc. for the design of a part of a fuel cell.1 Proton Exchange Membrane (PEM) fuel cells convert chemical energy into electrical energy through an electrochemical reaction between hydrogen fuel and an oxidant. Each cell consists of a pair of fluid flow plates separated by a solid polymer electrolyte membrane that allows the passage of protons. Hydrogen fuel is fed via channels to one plate (the anode) and an oxidant is fed via channels to the other plate (the cathode). A catalyst triggers a chemical reaction at the anode, which splits the hydrogen into protons and electrons. The protons pass through the membrane and the electrons travel along an external circuit to the cathode, when they combine with the protons and the oxidant to form water, which flows out of the cell.
Multiple fuel cells are typically stacked side-by-side to generate the desired level of power. Fluid flow plate construction typically involves compressing materials, such as graphite, sealing to prevent gas permeation, and engraving fluid channels into the face of the plate. Reduction of plate thickness is limited by compression and engraving processes, which can make the material brittle or increase permeability.
The patented fluid flow plate assembly consists of a network of conducting fibers joined to form an electrical path. Spaces within the fiber matrix are filled with a rigidizing material, which may also be used to form the fluid flow channels. Master Bond EP29LPSP was cited as an appropriate material for the rigidizing substance. The epoxy electrically isolates the conductive matrix from fluid in the flow channels while strengthening the plates and fortifying the fuel channels, allowing for increased compression and thinner plates than prior designs. With a density of 1-2 g/cm3, depending on whether or not a filler is used, EP29LPSP contributes to a lighter plate, which can be advantageous for fuel cells used in automotive designs. The overall fluid flow plate design facilitates reduced fuel cell volume for a given power output when stacking multiple fuel cells together.