Fuel cells offer a form of clean energy across many sectors and are of particular interest in vehicles, where they produce no emissions. The production of fuel cells requires the use of a rapid laser welding process; however, welding at too high a speed results in humping, marked by surface irregularities on the weld seam.
A team led by researchers at Penn State has combined observation and analytical modeling to identify the conditions that produce humping at high laser welding speeds and to adjust the process parameters to increase weld speed without causing surface irregularities. They published their results in Nature Communications.
"We wanted to increase the laser welding speed to increase the production rate for fuel cell bipolar plates, which are an important component in fuel cells for energy generation," said corresponding author Jingjing Li, Penn State professor of industrial and manufacturing engineering.
Bipolar plates are formed by welding two panels together. The channels that form in the bipolar plates are necessary infrastructure for energy generation in fuel cells. The production rate of bipolar plates was previously limited because welding speeds were restricted to prevent humping.
"Previously, the maximum welding speed was 20 meters of stainless steel produced per minute before humping would occur," said first author Zen-Hao Lai, a doctoral student in the Department of Materials Science and Engineering. "Through our work, we increased that limit to 75 meters per minute."
Lai said that a production rate of 75 meters per minutes translates to approximately 80,000 fuel cells per year, with each fuel cell consisting of two welded bipolar plates. Automotive bipolar plates typically range in size between eight-by-eight inches to 12-by-12 inches.
