Patent ID: 8921010

Claim:
A method of preparing a fuel cell unitized electrode assembly having a plurality of edges, which method comprises: forming a multi-layer sandwich comprising a first gas diffusion layer having upper and lower surfaces extending throughout the entire electrode assembly, a first electrode catalyst extending throughout the entire electrode assembly, either (a) a first thermoplastic polymer film disposed on said upper surface of said first gas diffusion layer, or (b) a second thermoplastic polymer film disposed on said lower surface of said first gas diffusion layer, or (c) both said first and second thermoplastic polymer films, a proton exchange membrane electrolyte extending throughout the entire electrode assembly and having a first surface adjacent to said first electrode catalyst, a second electrode catalyst extending throughout the entire electrode assembly and adjacent to a second surface of said proton exchange membrane electrolyte, a second gas diffusion layer extending throughout the entire electrode assembly, having upper and lower surfaces, and either (d) a third thermoplastic polymer film disposed on said upper surface of said second gas diffusion layer, or (e) a fourth thermoplastic polymer film disposed on said lower surface of said second gas diffusion layer, or (f) both said third and fourth thermoplastic polymer films, said thermoplastic polymer films extending inwardly from said edges a distance to provide a fluid edge-seal about the periphery of said unitized electrode assembly; and bonding said sandwich together in only a single step comprising applying a clamping force and ultrasonic vibrational energy to said sandwich to cause said thermoplastic polymer films to impregnate and bond said gas diffusion layers and said electrode catalysts.