Experimental evaluation of a feature based bipolar plate forming approach in a hybrid tool

¹ Fraunhofer Institute for Production Technology IPT, Aachen, Germany
² Laboratory for Machine Tools and Production Engineering (WZL) of RWTH Aachen University, Germany

^* Corresponding author: dennis.albers@ipt.fraunhofer.de

Abstract

The bipolar plate is a core component of a fuel cell and makes a decisive contribution to both system weight and cost. To reduce costs, metallic foils have been formed for several years to replace the conventional milled compound plates. The main challenge in forming is that the channel geometries must be produced with the highest accuracy requirements. Tolerances of a few micrometers should be maintained. The combination of high accuracy requirements with target production speed of less than one second and the complex geometric designs of flow fields pushes conventional forming technologies to their process limits. To meet this challenge, a procedure for feature-based forming has been developed (IDDRG2024) that enables multi-stage and hybrid forming. This allows bipolar plates to be manufactured independently of design but in a feature-specific production process. This previously developed theoretical process model will be physically validated and tested for effectiveness in investigations to be presented. For this purpose, a hybrid tool consisting of conventional stamping and rubber pad forming is set up, which is combined using precision workpiece transport. Using this tool, hybrid forming tests can be carried out based on previous numerical analysis to validate the procedure and derive an optimized process chain.