Bipolar plates are a key component in electrolyzers and fuel cells, which are needed for many hydrogen systems. The problem is that the current process of producing bipolar plates is expensive, which impedes the adoption of hydrogen technology — and that, in turn, stands in the way of solutions such as broad-based, low-cost use of cars powered by hydrogen fuel cells. This potential can only be unleashed by lowering the mass production costs of the core components involved. The Fraunhofer Institute for Machine Tools and Forming Technology IWU has taken a major step toward lower costs and mass production of bipolar plates by introducing an innovative system for roll embossing: BPPflexRoll.

One of the reasons that metallic BPPs are so expensive is that they are produced in discontinuous batches. In the newly developed technology, the structure of the bipolar plate is embossed using a pair of rollers, with the wafer-thin metal band running continuously between them.

The main advantage of this method is the high process speed, which leads to a substantial increase in unit quantity output, economies of scale and, ultimately, significantly lower costs. Flexibility is another of the system’s advantages: The number of roller sets required can be adjusted individually, depending on the geometry of the bipolar plates.

Sustainability

Since the rollers used to form the flow channels have approximately only one line contact with the workpiece, the step-by-step forming can reduce the process forces by a factor of ten on average compared to conventional embossing. That results in smaller, lower-cost machine technology. Flexibility is another of the system’s advantages: The number of roller sets required can be adjusted individually, depending on the geometry of the bipolar plates.

Future Outlook

The new system represents a key step towards cognitive forming machines that can monitor and control themselves via sensors and intelligent algorithms. BPPflexRoll can be used in a variety of ways for rolling thin sheet metals that require a high degree of precision. It represents a new generation of digital machine technology where software solutions use production data to control the hardware involved (smart systems). The aim is to allow for the highest possible degree of closed loop control.