Shutdown purging method of fuel cell system, fuel cell system and vehicle

Abstract

The invention relates to the field of fuel cells, in particular to a shutdown purging method of a fuel cell system, the fuel cell system and a vehicle. The method comprises the following steps: acquiring a first alternating-current impedance value of the fuel cell system entering on-load purging, determining the number of times of measuring the alternating-current impedance value in the on-load purging process according to the first alternating-current impedance value, and calculating the interval time of measuring the alternating-current impedance value and the on-load purging time; and when on-load purging is executed abnormally, first fault time is determined, a fault alternating-current impedance value is calculated according to adjacent measurement time for measuring alternating-current impedance and a measurement impedance value corresponding to the measurement time, no-load purging time is calculated according to the fault alternating-current impedance value, and shutdown purging opportunity is judged. According to the method, the sufficiency and suitability of shutdown purging are ensured, and the safety of the fuel cell system when the fuel cell system is reused under the low-temperature condition can be realized; and the durability of the fuel cell system is improved, and hydrogen energy and additional electric energy of system application are saved.

Description

technical field [0001] The invention relates to the field of fuel cells, in particular to a method for shutting down and purging a fuel cell system, a fuel cell system, and a vehicle. Background technique [0002] A fuel cell is an electrochemical reaction device that generates water by the reaction of hydrogen and oxygen in two half-electrodes, converting chemical energy into electrical energy and converting it into thermal energy with efficiency loss. The fuel cell system is composed of a fuel cell, an air supply system, a hydrogen supply system, a cooling system, and a control system. All systems work together to ensure that the fuel cell is in the expected working state. Hydrogen proton exchange membrane fuel cell has been widely researched and applied due to its characteristics of no pollution and high conversion rate. [0003] When the hydrogen proton exchange membrane fuel cell system is used in the field of transportation, it must meet the three harsh environmental ...

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Problems solved by technology

It is also possible to measure the AC impedance multiple times during the expected shutdown and purge period after the AC impedance is measured for the first time, so as to repeatedly calculate and correct the expected shutdown and purge time of the fuel cell and update it in the control implementation scheme; in the above-mentioned scheme one , the difference between on-load purge and no-load purge during fuel cell shutdown cannot be clarified, and when a failure occurs during fuel cell shutdown and purge that cannot continue to carry out on-load purge, the on-load purge cannot be allocated reasonably and no-load purging time, in addition, there is also the problem that the fuel cell cannot be accurately shut down and purged when th

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