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A passive thermal management system (TMS) using composite phase change material (PCM) for large-capacity, rectangular lithium-ion batteries is designed. A battery module consisting of six Li-ion cells connected in series was investigated as a basic unit. The passive TMS for the module has three configurations according to the contact area between cells and the composite PCM, i.e., surrounding, front-contacted and side-contacted schemes. Firstly, heat generation rate of the battery cell was calculated using the Bernardi equation based on experimentally measured heat source terms (i.e. the internal resistance and the entropy coefficient). Physical and thermal properties such as density, phase change temperature, latent heat and thermal conductivity of the composite PCM were also obtained by experimental methods. Thereafter, thermal response of the battery modules with the three TMS configurations was simulated using 3D finite element analysis (FEA) modeling in ANSYS Fluent.

Centrifugal compressors used in polymer electrolyte membrane fuel cell systems are different from turbochargers in internal combustion engines, because they are required to work at high speed, low mass flow rate, narrow range which nears surge boundaries. In order to meet these requirements, a centrifugal compressor’s volute is designed, analyzed and optimized on its cross-section area, shape of volute tongue and tapered angle of exit. The numerical results show that surge boundary of the compressor is influenced by spiral area significantly and that volute tongue has a major impact on aerodynamic performances at high mass flow rates.