The welding process used for manufacturing the ultra thin bipolar plates must be of the highest quality and this is best achieved with the laser, asserts Dr. Christian Schmitz, member of the managing board and CEO of laser technology for TRUMPF SE. PHOTO courtesy TRUMPF.
The global end of the internal combustion engine is in sight. By 2035 no more new internal combustion engines are to be registered in North America or Europe. But battery power is not the only solution for the mobility of the future and TRUMPF believes fabricators have a significant role to play in the development of another technology: the hydrogen fuel cell.
For Canadian job shops serving the automotive sector it’s worth paying attention to the potential opportunities presented by this latest development.
Battery power is the preferred propulsion option for passenger cars, but the greater weight of heavy duty vehicles such as trucks and buses and the much longer distances they must travel makes battery-based electromobility an impractical option for them unless they’re willing to accept major restrictions in payload. Hydrogen fuel cell technology, which provides longer range and shorter refuelling stops, seems a much better option.
TRUMPF believes hydrogen-technology breakthroughs will only come when there are fast and reliable means of producing such fuel cells. Currently, the high cost of hydrogen fuel cells poses a major obstacle.
At the heart of a mobile fuel-cell system is a package of bipolar plates called a stack. This stack assembly allows hydrogen to react with oxygen from the air. The resulting combustion generates water, electricity and heat, and the hydrogen vehicle uses the electricity to power its electric motor.
A bipolar plate consists of two stainless-steel plates that are welded together. Each plate is approximately the size of an A4 sheet of paper and is not much thicker than a human hair. Welding these two stainless-steel sheets is far from easy. It requires a perfect weld, a fine seam that is barely visible to the naked eye, and the consequences of even the most minor imperfection are disastrous. H2 is the smallest molecule in the world (much smaller than the methane in natural gas) and can escape through even the tiniest pore. A leak in just one of the bipolar plates renders the whole stack unusable, so one of the toughest challenges of joining bipolar plates is finding a way to weld complex geometries over a very large area with tremendous accuracy.
And that’s where TRUMPF believes it can play a pivotal role in making the fuel-cell manufacturing process more efficient and cost-effective in the future.
“The welding process must be of the highest quality. This is best achieved with the laser,” asserts Dr. Christian Schmitz, member of the managing board and CEO of laser technology for TRUMPF SE. “…Without highly sophisticated manufacturing technology and lasers, these ultra-thin metal plates could not be produced economically today.”
Schmitz says TRUMPF is already cooperating with all the leading companies involved in the fuel cell
field and can draw on extensive expertise in welding bipolar plates.
“In our laser application centres, we work together with our customers to advance the production of bipolar plates – just as we have already successfully done for the production of batteries for electric cars…Fuel cells are a future topic for us. We see potential above all in heavy duty transport,” Schmitz says adding that many truck manufacturers around the world are currently planning to place hydrogen-powered trucks on the road or have already done so. Suppliers and OEMS have already entered small-scale fuel cell production and the European Union is getting behind the technology with up to $5.4 billion in investments. Japan, France, South Korea, Australia, Norway and the Netherlands have also developed national hydrogen strategies.
The welding of bipolar plates also requires comprehensive tests to check that the welds are strong and gastight. TRUMPF is working on integrated sensor solutions to ensure quality standards are met while reducing the time and effort required to carry out testing.
According to a forecast by the China Society of Automotive Engineers, there could be more than one million fuel cell vehicles on the road in China by 2030.
Nor are the trucking and bus industries the only potential beneficiaries of fuel cell technology. Schmitz says hydrogen fuel cells are also suitable for supplying power to industrial plants and residential buildings, in steel production, the chemical industry and in aviation. While the stationary applications differ from the mobile applications in terms of the construction and materials, the tasks for the laser are basically the same. SMT
