Laser Sealing Technique for Fuel Cell Application

A complete fuel cell stack comprises several single cells with end plates, collector plates, monopolar plates, gasket, and MEA components. Electron generated from cells can be conducted through bipolar plates. However, the amount of cell components increases with great cell power, which is inconvenient for fuel cell assembly process and mass production. During 2010, fuel cell systems were manufactured more than 15,000, the power of which was more than 8MW. With the market growth of hydrogen energy and fuel cells, developing high-speed modular assembly technique becomes a priority research to meet market requirements. Furthermore, extra back pressure is necessary for fuel gas in the fuel cell stack utilized in transportations to promote the fuel cell performance; gas leakage therefore becomes an important issue with an increase in the amount of cell components and gas pressure.

Consequently, laser welding technique is utilized in fuel cell stack design, which has advantages of narrow welding path and high welding aspect ratio, small amount of deformation for specimens, fast welding velocity, high strength welding, and easily integrated into automation equipment, to achieve the objective for high strength and accuracy modular sealing and promoting production capacity and quality. Parameter analysis for laser welding, optical measurement tests and peel tests are conducted to obtain the optimal welding quality and strength, the sealing strength of which can sustain at least 0.4 MPa stress (4 atm pressure). Moreover, new fuel cell stack structure is subsequently designed for this high strength and accuracy modular sealing technique in the future research.