Three challenges
Gas-tight welding: The heater for electric cars conducts fluid through heating lines. "Clearly, liquid and high voltage don't mix well in an electric car," says Schmalenberg, "so the aluminum housing has to be welded absolutely gas-tight." However, making aluminum gas-tight is not an easy task. Electron beam welding in a vacuum is too slow and expensive for the mass production of electric cars. However, fast laser welding often results in gas pockets that impair the tightness.
Precise contact for copper: In order for the current to flow properly in the heater, copper is required, which must of course be contacted by welding. Copper is reflective and therefore not an easy mating part for lasers. However, deep weld seams are a danger for the underlying layers. "For this reason we need the ability to precisely regulate the welding depth of the laser. It wouldn't work with the classic infrared laser," explains Schmalenberg.
Structuring conductive paths: In order to keep the heater as thin as possible, Webasto does not want to attach the conductors, but rather insert them directly into the thin metal layer on the surface. "When structuring, we want clean ablation and precise edges. To avoid the risk of product defects, there must be no melting of the material," says Schmalenberg.
