Development of a Laser Processing System for Fuel Cell Bipolar Plates in Eco-Friendly Propulsion Applications and Evaluation of Cutting Performance

Recently, various eco-friendly energy technologies have been actively developed worldwide, with fuel cell technology attracting significant attention due to its ability to directly generate electricity through electrochemical reactions without converting chemical energy into mechanical energy. Fuel cells are being developed and commercialized across a wide range of applications, including building, power generation, and transportation systems. In particular, the adoption of ultra-thin metallic bipolar plates has been expanding to achieve weight reduction in transportation fuel cells for automobiles, ships, and aircraft, driving the demand for high-quality automated manufacturing processes. In this study, a novel scanner-nozzle integrated laser processing system incorporating a two-dimensional (2D) on-the-fly function was developed for cutting 0.075 mm-thick STS316L ultra-thin bipolar plates. Cutting performance was evaluated by comparing nozzle-free scanner cutting and nozzle-integrated scanner cutting conditions. In nozzle-free cutting, relatively sound cut sections were obtained at laser powers of 2-3 kW and cutting speeds of 1,500-3,000 mm/s; however, complete removal of molten metal remained difficult. Superior cutting quality was achieved when N2 cutting gas was supplied through the nozzle, and the optimal condition was identified as single-mode laser, Duty 60%, and 2 kHz pulse modulation, under which high-quality cutting was maintained even at a reduced gas pressure of 5 bar.