Study On Key Technologies Of Air-Cooled And Self-Humidifying Pemfc Power System

With the high efficiency and environment-friendly advantage, fuel cell has become an important part of the new energy resources. Among this, Proton Exchange Membrane Fuel Cell, PEMFC, has broad application prospects in many fields because of its distinct advantages of specific power, high energy conversion efficiency, fast start and environmental protection.In recent years, the development of air cooling technology and self-humidifying technology leading the emergence of air-cooled and self-humidifying PEMFC. The cathode structure of fuel cell is open, which is direct contact with air. Such PEMFC power systems without external water circulation system and air compressor system have the advantage of simple structure, but also bring problems as worse environment adaptability, high coupling of water and heat management, and less control parameters. Therefore, studying the influences of environmental conditions on the PEMFC and researching the control strategies at different operation stages from the perspective of PEMFC power system have great significance for improving its performance, prolonging its working life and accelerating its commercialization process.This paper take the Ballard FCgen (?)1020ACS air-cooled and self-humidifying type PEMFC as the research object, through the experimental study on the effect of different environmental temperature and humidity on the PEMFC optimum operating temperature, the relationship between the fuel cell optimal operating temperature and the temperature and humidity of the environment and the output current was determined. Using the independent design of fuel cell control system, to control the air-cooled PEMFC optimum operating temperature by way of PID control method. Thereby to ensure fuel cells work in a best state during the whole operation of fuel cells in different environments.For catalyst’s carbon carrier corrosion that caused by the hydrogen oxygen interface,which appears at PEMFC anode side in startup and shutdown process, this paper study the effects of directly start-up, start-up with hydrogen blowing the anode and start-up with starting load on the PEMFC. A PEMFC power system startup control strategy was designed on this basis. And the PEMFC power system shutdown control strategy was designed by studying the effect of directly shutdown and shutdown withanode exhaust, add the auxiliary load and the stack temperature control after shutdown on the output characteristics of PEMFC under different operating current.On the basis of the research on environment adaptability and start-up and shut-down control strategy, a fuel cell test system based on Siemens S7-1200series PLC and monitoring software platform LabVIEW was designed and reported in this paper. By fully considering the sensitivity requirements of timing and control for air-cooled PEMFC, timing control of start and shutdown, the optimal operating temperature control in different environments, startup and shutdown control and anode exhaust gas control are well achieved. In addition, the system can adjust online operating parameters according to the actual operating status. And a kW power system of air-cooled self-humidifying PEMFC was designed, which coupled with alloy hydrogen storage system. And using hot air flow that come from fuel cell cathode exports to heat the metal hydrogen storage device, to some extent, realized coupled thermal management of PEMFC power system. Therefore, the foundation was laid for the follow-up study of power system coupled thermal management.