Optimization Design Of The Fuel Cell End Plate Clamped With Belts

Fuel cell is a fast developing new electrochemical device. It has good potential applications in aviation, aerospace, automobile, submarine and mobile device. The endplates of a fuel cell stack provide clamping force to the internal components with fasteners. They are important components affecting the stack performance. In the present thesis, the deformation of internal structure and gas transportation in the internal components under clamping force are analyzed using finite element method. Aiming at improving the deformation uniformity of the internal contact surfaces, the endplate of a large fuel cell stack clamped with belts is optimized with shape and topology optimization method.Firstly, using Abaqus, the stress and deformation of a large fuel cell stack clamped with belts are analyzed. It can be found that an obvious non-uniform compression appears on the internal structure of the fuel cell stack. Then, using Comsol, the compression on gas diffusion layer resulting from a typical bipolar plate is studied. A coupled analysis is carried out for the deformation of the gas diffusion layer, the change of porosity, the gas transportation and the distribution of compression pressure. It is found that they obviously affect the efficiency of the fuel cell electrochemical reaction. The efficiency of electrochemical reaction will be decreased by the non-uniform compression caused by improper design endplates. This indicates the necessity to improve the compression uniformity of the internal structure by optimizing the endplates.To acquire more proper design endplates of a fuel cell stack clamped with belts, using Ansys and Isight, considering the objective of minimizing the standard deviation of normal displacement of the contact surface, the outline of endplate section of stack is optimized with simulated annealing algorithm. Then the section outline providing the most uniform compression to the internal components under clamping force is acquired. Based on this optimized section outline, using Optistruct, the optimized topology structure is obtained with a further topology optimization. Stretching the section after shape and topology optimization, a 3-D endplate is acquired. By optimizing the several control planes on the stretched structure, the 3-D endplate can be finally optimized. After optimization, the deformation uniformity of the internal contact surface is increased by 9.16% under the clamping force.. The optimized endplate structure satisfies the strength requirements. This work is valuable for optimal design and manufacturing of endplates of fuel cell stack.