Characteristic study on fuel cell/battery hybrid power system on a light electric vehicle

A light electric vehicle (LEV) equipped a hybrid power system has been developed in the present work. The hybrid power system consisted of a proton exchange membrane (PEM) fuel cell and a lithium-ion battery. The former serves the major propulsion power, while the later takes some of the peak power requirement as well as allows regenerative braking. First, major components of the hybrid power system such as a fuel cell stack, a membrane humidifier, a lithium-ion battery pack, a microcontroller, a DC/DC converter, and hydrogen storage canisters (HSCs) are developed and verified. Special attention will be placed on the implementation of the stack-humidifier assembly and the hydrogen storage canister. Then, a breadboard test to assess the efficiency of the hybrid power system is provided. Subsequently, a driving test and demonstration of the hybrid LEV is carried out. Finally, the proportion of power from the fuel cell and the lithium-ion battery is analyzed under various driving conditions such as idle, starting, acceleration, and braking. Results of this work might help directing future studies on the hybrid power system in the most promising way.

► The design of stack-humidifier assembly enables in the reduction of components and space saving.
► Thermal wastes from the fuel cell stack have successfully been recycled to the metal hydrides to supply the heat for desorption of hydrogen.
► Thermally coupling the fuel cell stack and the metal hydride storage benefits the hybrid power system of high efficiency.
► The efficiency of the hybrid power system is greater than that of the prior generation.