Fuel cell stack clamping structure and solid oxide fuel cell stack
A clamping structure for a planar solid oxide fuel cell stack comprising a flexible sheet and a rigid, thermally insulating end block, the flexible sheet being capable of bending into a primarily convex shape, the rigid, thermally insulating end block shaped as a rectangular base with a planar surface and an opposing surface that is primarily convex in shape, the flexible sheet being placed adjacent to the opposing surface of the rigid, thermally insulating end block, the flexible sheet thereby bending to obtain a shape that is primarily convex. The invention also relates to a solid oxide fuel cell stack and a process for the compression of the stack.
1. A process for compression of a solid oxide fuel cell stack, comprising interposing one or more planar solid oxide fuel cells between end plates, placing adjacent to at least one end plate a clamping structure comprising a flexible sheet and a thermally insulating end block, the flexible sheet being capable of bending into a primarily convex shape, the thermally insulating end block shaped as a rectangular base with a planar surface and an opposing surface that is primarily convex in shape, placing the flexible sheet adjacent to the opposing surface of the thermally insulating end block, bending the flexible sheet to obtain a shape that is primarily convex and placing the at least one end plate in contact with the planar surface of the rectangular base of the thermally insulating end block and exerting a compressive force across each solid oxide fuel cell surface, wherein the flexible sheet does not have to withstand bending forces and has a thickness of 0.05-5 mm.
2. The process according to claim 1 , wherein the compressive force is obtained using nuts, springs and tie-rods.