Design And Development Of EIS Online Measurement System For Internal Resistance Of PEM Fuel Cell

Fuel cell is considered as the final form of clean energy,which has the characteristics of high energy efficiency and pollution-free.As the most commonly used fuel cell,proton exchange membrane fuel cell(PEMFC)has attracted the attention of researchers,enterprises and research institute.However,the commercialization process of PEMFC has been restricted by price,lifespan and stability.The internal resistance of fuel cell is an important parameter to characterize the operating state of fuel cell.The accurate acquisition of this parameter can provide guidance for the subsequent strategies to improve the stability and life of fuel cell.At present,the internal resistance detection system is integrated with other functions,so it is very inconvenient to measure and difficult to realize on-line detection.Therefore,it is very necessary to design an independent online PEM fuel cell internal resistance detection system.Based on this purpose,the following work is done in this paper:(1)Three equivalent models and four internal resistance detection principles of proton exchange membrane fuel cell(PEMFC)are analyzed.On this basis,the overall scheme of internal resistance detection based on Dicks-Larminie equivalent model and EIS detection method is determined.(2)According to the overall scheme,the system hardware is designed.The hardware is divided into five parts: 1)MCU control circuit design;2)patrol sampling circuit design;3)AC / DC signal processing circuit design;4)sine small signal generator circuit design;5)power supply module circuit design.Five parts cooperate with each other to complete the internal resistance detection of PEMFC.The part two inspection sampling circuit and part three AC/DC signal processing circuit are the core and difficulty of the whole hardware system,so some problems and solutions encountered in the design process are described in detail.(3)According to the hardware design,completed the related software programming tasks.The address bits and data bits of each hardware chip are written to realize the functions of chip selection inspection,AC filtering,amplitude and phase conversion reading,small signal generation,A/D conversion and other functions,as well as auxiliary internal resistance detection.(4)According to Dicks-Larminie equivalent transformation model,a single chip PEMFC was built,and the internal resistance detection system was used to detect the internal resistance.The experimental results meet the design needs and the scheme design is correct.Finally,the possible problems in the system and the optimization part that can be improved are analyzed,and the solutions are proposed in the Prospect section.