Abstract
Polymer Electrolyte Membrane Fuel Cell (PEMFC) is widely researched, reflecting the energy problems in recent years. The voltage for each PEMFC unit cell is about 1V, and accumulating to the series makes it possible to get high voltage necessary for drive. And the use of the Computer Aided Engineering (CAE) technology is an indispensable process in the design of fuel cell because of the cost decrease and shortening the development time. When we apply CAE technology to fuel cell stack structural analysis, however, it is necessary to think each layer as contact determinations. So it is very difficult to obtain the stable calculation result because of strong nonlinearity.
On the other hand, homogenization method to which the theory is constructed in the latter half of 70´s has developed as technique that mathematically obtains strict result in a microscopic and macroscopic scale by introducing the homogenization coefficient in which microscopic structure is reflected. In recent years the practical use of homogenization method combined with CAE technology is advancing in the industrial world.
In this paper, the theory of homogenization is enhanced, and we introduce the case applied to the structural analysis of fuel cell. At first homogenization theory was enhanced, and formulated to apply the structure that is periodic in one direction and has the load distribution in two directions. In this enhancement we had 3steps, macro1D-micro1D, macro1D-micro3D and macro3D-micro3D, the last one was theorized by using 0-order approximation and correction term. Next, microscopic structure was corresponded to cell, macroscopic structure to stack and the enhanced formulation had been applied to execute structural analysis. We calculate microscopic structure to obtain homogenization coefficient, macroscopic structure using obtained homogenization coefficient and microscopic structure to evaluate each microscopic structure. As a result it is possible to obtain the solution for a large-scale, nonlinear problem including nonlinear spring, nonlinear material property and many contact determinations.
Keywords: Fuel Cell(FC), Homogenization, Structural Analysis, Nonlinearity, CAE