Process for producing laminated exfoliated graphite composite-metal compositions for fuel cell bipolar plate applications

Abstract

A process for producing an electrically conductive laminate composition for fuel cell flow field plate or bipolar plate applications. The process comprises: (a) feeding a thin metal sheet, having a first surface and a second surface, into a consolidating zone; and (b) feeding a first exfoliated graphite composite sheet onto the first surface of the metal sheet to form a two-layer precursor laminate in this consolidating zone; wherein the exfoliated graphite composite sheet comprises (i) expanded or exfoliated graphite and (ii) a binder or matrix material to bond the expanded graphite to form a cohered. The process preferably further comprises (c) feeding a second exfoliated graphite composite sheet onto the second surface of the metal sheet to form a three-layer precursor laminate. Both the first and second exfoliated graphite composite sheet may further comprise particles of non-expandable graphite or carbon in the amount of between 3% and 60% by weight based on the total weight of the non-expandable particles and the expanded graphite. Surface flow channels and other desired geometric features can be built onto the exterior surfaces of the laminate to form a flow field plate or bipolar plate by a procedure such as in-line embossing or molding. The resulting laminate has an exceptionally high thickness-direction conductivity and excellent resistance to gas permeation.

Dependencies are inferred from the claim text.