Active process control in series production of high-precision embossed bipolar plates

• Applicant: Professor Dr.-Ing. Mathias Liewald
• Subject Area: Primary Shaping and Reshaping Technology, Additive Manufacturing ; Measurement Systems
• Term: since 2021
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 460294948

The availability of powerful energy carriers is a basic prerequisite for the successful electrification of passenger and commercial vehicle transport. Therefore, limited energy and power densities of even modern accumulators cause fuel cell technologies to increasingly become important again. Critical components of efficient fuel cell systems are in particular the bipolar plates (BPP), which are responsible for supplying the reaction gases and removing the water produced. In modern systems approximately 600 BPP are installed! Due to the better electrical conductivity and the more cost-effective manufacturing process, formed metallic BPP are technically and economically superior to BPP made of graphite. However, typical forming defects such as tearing and spring buckling effects can occur in sheet metal forming even with slightly fluctuating process parameters. To date, most of these defects cannot be consistently detected and prevented due to specific manufacturing processes. As a result, downstream quality assurance has to be performed by means of costly and time-consuming sampling tests. In addition, there is no industry-standard system for identifying critical process parameters in order to specifically eliminate these defects. Until now!By combining an extensive simulation toolchain with an inline-capable, full-surface 3D measurement of each manufactured component, an overall system for active process control and quality assurance in series production is realized within AKS-Bipolar. Objective is a significant reduction of scrap parts in existing processes, e.g. by concrete recommendations for eliminating defects during production but also by further development of numerical simulation methods. Using these methods, new component geometries can be designed in a functionally suitable and process-safe way. The success of the project will be proven by means of a demonstrator based on a concrete, industrial production example of the project partner ThyssenKrupp Systems Engineering (tk SY).Due to the digital-holographic sensor technology of Fraunhofer IPM, high-precision 3D data is available for the first time in high volume and real time, enabling very fast and accurate comparison with the simulation results calculated at IFU for process design. Based on this data, the simulation toolchain to be developed generates and optimizes a digital twin of the forming process considered. This digital twin can be used to numerically detect recurring production problems and to control suitable counteractions according to the objectives of Industry 4.0 production.

• DFG Programme: Research Grants (Transfer Project)
• Application Partner: Chemische Werke Kluthe GmbH; thyssenkrupp System Engineering GmbH
• Cooperation Partner: Professor Dr. Daniel Carl