Patent ID: 7273671

Claim:
A fuel cell comprising a tubular casing, an electrolyte layer received in said tubular casing, a first gas diffusion electrode completely defining a fuel gas passage and a second gas diffusion electrode completely defining an oxidizing gas passage, wherein said first and second gas diffusion electrodes interpose said electrolyte layer, wherein: said first and second gas diffusion electrodes each comprise a plurality of layers of material stacked in the axial direction of said tubular casing, wherein said fuel and oxidizing gas passages, which extend in the axial direction, each have a non-uniform diameter and said first gas diffusion electrode extends continuously along said fuel gas passage; said second gas diffusion electrode extends continuously along said oxidizing gas passage, and wherein said tubular casing comprises high polymer solid electrolytic material surrounding said first and second gas diffusion electrodes, and said electrolyte layer is formed of said high polymer solid electrolytic material; and said fuel cell further comprises a first lead attached to said first gas diffusion electrode at one axial end of said tubular casing such that said first gas diffusion electrode is electrically connected to an external circuit by said first lead and a second lead attached to said second gas diffusion electrode at the other axial end of said tubular casing such that said second gas diffusion electrode is electrically connected to said external circuit by said second lead; said fuel gas passage and said oxidizing gas passage each having an entrance at a first common plane, wherein said entrance of said fuel gas passage is separate and distinct from said entrance of said oxidizing gas passage; and said fuel gas passage and said oxidizing gas passage each having an exit at a second common plane, wherein said exit of said fuel gas passage is separate and distinct from said exit of said oxidizing gas passage, wherein the first and second common planes extend orthogonally relative to the axial direction of said tubular casing.