MC LaserBip – Welding oversized compound bipolar plates for fuel cells with a laser

Current manufacturing processes for graphite-based compound bipolar plates such as injection moulding, extrusion or hot pressing reach their limits with active areas of over 200 cm² due to the processability of the material. To increase the overall performance of the fuel cell stack, it is not enough to simply increase the number of cells. Especially as the internal electrical resistance increases steadily and the temperature and gas management as well as the mechanical load in the stack become more challenging.

Cells with a larger active area would deliver a higher total current at the same cell voltage and therefore more power per individual cell. A stack would therefore require fewer cells for the same total output.

The researchers are paying particular attention to the choice of materials for both the compound inserts and the frames. They are investigating the suitability of the material with regard to the production of the plates, the welding process and the application in fuel cells.

Design, production, tests: The production process for inserts and frames will initially be validated using a 25 cm² prototype. In-situ tests under extreme conditions will provide further insights into the weld seam behavior, performance and degradation behavior. Bipolar plates with an active area of up to 200 cm² and multiple inserts will then be manufactured and tested in the laboratory within a short stack.

MC LaserBIP thus addresses a key challenge in fuel cell development: overcoming existing size limits to achieve freely scalable bipolar plate formats. The prospects of increasing the efficiency of fuel cell component production and reducing costs at the same time are certainly good.