NOK Corp developed a gasket that enables to reduce fastening force for fuel cells.
The gasket, "Cell Seal," is used for sealing between stacked cells and prevents hydrogen, air, etc from leaking. Using a rubber whose reaction force is low, it realizes reliable sealing while fastening cells with a force half that of conventional fuel cell gaskets.
The fastening power of a rubber depends on its reaction force. Therefore, conventional gaskets using a rubber with a large reaction force have a strong fastening power. However, they can cause cracks on separators made of carbon and deformation of stainless steel separators, making tight sealing impossible. Still, a certain level of fastening force is required for gaskets, which cannot be used for sealing without being pressed.
On the other hand, because the reaction force of the new gasket is small, it can be fastened with a smaller force. In addition, its cross-section has a wave-like shape (Fig. 2), enabling a large amount of compression and sealing with a smaller force.