A fuel cell is an electro chemical energy conversion device, which produces electricity from external supplies of fuel (on the anode side) and oxidant (on the cathode side). These react in the presence of an electrolyte to produce energy.
Since a typical fuel cell produces less than one volt, in practical application cells are ‘stacked’ in parallel to create a useful voltage. Thus a typical fuel cell is made up of many thin sheets, usually of stainless steel, which must be welded together to form the fuel cell stack.
Welding of the plates is by far the most time consuming process involved in the manufacture of fuel cells – there is about one meter of welding required for every single plate in every single fuel cell stack – that is about 400m of welding for each eco-car. Optimising the welding process offers the opportunity to make significant savings in the cost of production of fuel cells.
The issues here are all related to the difficulty of achieving a small, clean, reliable weld at viable production speeds using traditional laser welding techniques. To solve these problems, the leading-edge manufacturers are now looking to...