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As one of the most crucial components in electric vehicles, power batteries generate abundant heat during charging and discharging processes. Thermal management system (TMS), which is designed to keep the battery cells within an optimum temperature range and to maintain an even temperature distribution from cell to cell, is vital for the high efficiency, long calendar life and reliable safety of these power batteries. With the desirable features of low system complexity, light weight, high energy efficiency and good battery thermal uniformity, thermal management using composite phase change materials (PCMs) has drawn great attention in the past fifteen years. In the hope of supplying helpful guidelines for the design of the PCM-based TMSs, this work begins with the summarization of the most commonly applied heat transfer enhancement methods (i.e., the use of thermally conductive particles, metal fin, expanded graphite matrix and metal foam) for PCMs by different researchers.

The thermophysical parameters and amount of composite phase change materials (PCMs) have decisive influence on the thermal control effects of thermal management systems (TMSs). At the same time, the various thermophysical parameters of the composite PCM are interrelated. For example, increasing the thermal conductivity is bound to mean a decrease in the latent heat of phase change, so a balance needs to be achieved between these parameters. In this paper, a prismatic LiFePO4 battery cell cooled by composite PCM is comprehensively analyzed by changing the phase change temperature, thermal conductivity and amount of composite PCM. The influence of the composite PCM parameters on the cooling and temperature homogenization effect of the TMS is analyzed. which can give useful guide to the preparation of composite PCMs and design of the heat transfer enhancement methods for TMSs.

Water and thermal management is an essential issue that influences performance and durability of a polymer electrolyte membrane fuel cell (PEMFC). Water content in membrane decides its ionic conductivity and membrane swelling favors the ionic conductivity, resulting in decreases in the membrane’s ohmic resistance and improvement in the output voltage. However, if excessive liquid water can’t be removed out of cell quickly, it will fill in the pores of catalyst layer (CL) and gas diffusion layer (GDL) then flooding may occur. It is essential to keep the water content in membrane at a proper level. In this work, a transient isothermal one-dimensional model is developed to investigate effects of the relative humidity of inlet gas and cell temperature on performance of a PEMFC.

Proton exchange membrane fuel cells (PEMFC) are considered an environment-friendly alternative vehicle power in the future owing to their high power density and zero-carbon emission. To research the performance of the air supplied by the PEMFC air system, the PEMFC air system bench composed of an air compressor, cooler, emulated stack, back-pressure valve, and sensors was built. Then, a PEMFC system test bench composed of a hydrogen supply subsystem, stack, air supply subsystem, electronic control subsystem, and cooling subsystem was established. The fuel cell system control parameters and control method are complex due to the coupling and nonlinearity of the air supply system. The strategy composed of a feedforward table and piecewise proportional integral (PI) feedback control strategy was employed to regulate the pressure and flow rate of the air supply system.

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.

Proton Exchange Membrane Fuel Cell (PEMFC) which has advantages of starting fast, high energy density, high efficiency, lower operating temperature and little pollution is widely regarded as one of the most promising energy sources. The PEMFC system includes several subsystems such as air supply subsystem, hydrogen supply subsystem, thermal management subsystem, water management subsystem, energy management subsystem and so on. The Air supply subsystem has great influence on the performance and life of PEMFC stack. Whether oxygen supply in air supply subsystem is sufficient or not will affects reaction rate of fuel, the operating temperature and degradation of PEMFC stack and so on. To solve the issue of oxygen starvation in PEMFC stack, the control strategies for improving dynamic response and preventing air shortage of the PEMFC air supply subsystem are reviewed.