Starting and shutdown control method for proton exchange membrane fuel cell

Abstract

The invention provides a starting and shutdown control method for a proton exchange membrane fuel cell. According to the method, a whole fuel cell stack is divided into a plurality of cell modules; each cell module is connected with a modularized discharging circuit which is composed of a control switch, an auxiliary load and a crystal diode in mutual series connection; each modularized discharging circuit and a main load circuit are in series connection and are respectively connected with the cathode end and the anode end of the fuel cell; an air source is connected with the anode end of the fuel cell through an air blow-down valve; and air is used to purge residual hydrogen at the anode. During starting control, hydrogen is used to purge the anode, and the auxiliary load is used to control the voltage of the cell; and during shutdown control, introduction of air and introduction of hydrogen are successively stopped, a closed system of the auxiliary load is used for discharging, and introduction of air is cooperatively used for purging of the anode. The invention has the following advantages: consumption of time during shutdown of the fuel cell is reduced; the concentration of residual oxygen at the cathode is lowered down; reversal of poles of a single cell in the modules is prevented, and the phenomenon of reversal of poles of the fuel cell in the processes of shutdown discharging and air purging is prevented; and the system of the fuel cell is more simplified and is convenient to operate.

Description

technical field [0001] The invention relates to the field of proton exchange membrane fuel cells, in particular to a method for controlling start and stop of proton exchange membrane fuel cells. Background technique [0002] Fuel cell is an electrochemical power generation device. Due to its high energy conversion efficiency (50%~70%), environmental friendliness, low noise and other outstanding advantages, the research and development of fuel cell technology has attracted a lot of attention from governments and large companies. It is considered to be the preferred clean and efficient power generation technology in the 21st century. Among various types of fuel cells, proton exchange membrane fuel cells (PEMFC) are suitable for portable power sources and transportation vehicles. Fuel cells developed by most automotive companies also focus on PEMFCs. [0003] In addition to the advantages of all other fuel cells, proton exchange membrane fuel cells also have advantages that o...

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Problems solved by technology

[0009] The purpose of the present invention is to provide a proton exchange membrane fuel cell system for the current proton exchange membrane fuel cell system in the frequent start and stop process, the anode is easy to form a hydrogen / oxygen interface, resulting in the formation of a high potential of the cathode, thereby leading to the attenuation of fuel cell performance Battery start and stop control method

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