ZBT development support by means of thermochanical simulation and in-situ verification
By order of Scheuermann+Heilig GmbH located in Buchen, Germany, ZBT participated in the development of an innovative clamping system for fuel cell stacks. The main aim of the clamping system is to attain an even distributed mechanical pressure within fuel cells by ensuring the tightness of the fuel cell stack under operating conditions.
The clamping system has to achieve the mechanical stability of fuel cell stack and enable the fully automated stack mounting. ZBT supported the development of the clamping system for a standard 50cm2 ZBT fuel cell stack with regard to the functionality of the cell components. Assembly and test of the innovative fuel cell stack design was realized by ZBT and assisted by the simulations performed in ZBT.
Thermomechanical simulations (developed with the help of COMSOL Multiphysics®) have been performed during design process in order to analyze the clamping system. Beside the usual cell components e.g. bipolar plates, MEA and sealing, the simulation models contain sheet metal structures and pressure cells filled with liquid medium. The developed simulation models are utilized to ensure the uniform mechanical pressure distribution under stack operating conditions.
A fuel cell stack finally was assembled by ZBT using the developed clamping system. The performance and thermomechanical characteristics of the developed fuel cell stack have been successfully examined under cyclic operating conditions. Not only the applicability of the developed clamping concept was proven, also the long term stability and durability of the system have been investigated with the help of an automated cyclic operation process. Owing to the enhanced internal stress distribution with the help of innovative stack concept, the cell performance was very good.
The work was performed in the working group “stack development” of the department fuel cells and systems, which is responsible for the development of stack and mechanically relevant components (bipolar plate, gasket). Components and stacks are beeing designed using modern CAE tools and are being produced in prototype numbers eg. by injection moulding, milling, dispensing and printing. The experiencemade developing fuel cells is nowadsays also being transferend to electrolyzers and innovative flow battery concepts.
The development will be presented during F-Cell 2014 in Stuttgart / Germany by Wieland Bundschuh (Scheuermann+Heilig).
