Method for starting proton exchange membrane fuel cell under low-temperature state

Abstract

The invention relates to a method for starting a proton exchange membrane fuel cell under a low-temperature state. A mixed gas is introduced to a positive electrode for catalytic pre-heating, a tail gas of the positive electrode is introduced to a negative electrode, so that the mixed gas which does not react generates catalytic reaction in the negative electrode, and the effect of simultaneouslyrising temperatures of the negative electrode and the positive electrode is achieved. The method is improved on the basis of a traditional catalytic cold-starting method, the negative electrode and the positive electrode can simultaneously generate catalytic reaction, heat is provided for the cell, low-temperature starting at -45 DEG C even a lower temperature range can be achieved, fuel can be fully utilized, the starting power consumption of the cell is reduced, and the low-temperature starting time is greatly reduced.

Description

technical field [0001] The invention relates to the technical field of fuel cells, in particular to a method for improving the cold start of catalytic reactions of proton exchange membrane fuel cells. Background technique [0002] Proton exchange membrane fuel cell (PEMFC) can directly convert fuel hydrogen and chemical energy in the air into electrical energy. It has the characteristics of high energy conversion efficiency and no pollution. In our country to achieve the goal of energy saving, emission reduction, low carbon and environmental protection. The proton exchange membrane fuel cell is an extremely complex system, and its application in the automotive field will inevitably face difficulties such as storage and start-up under low temperature conditions. The single-cell structure of PEMFC generally includes an anode catalytic layer, a cathode catalytic layer and a proton exchange membrane. Both the anode catalytic layer and the cathode catalytic layer contain catalys...

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Problems solved by technology

Although these methods can successfully start the fuel cell at sub-zero temperatures, they all have the problem of increasing the volume and quality of the battery system, increasing the complexity and cost of the fuel cell system

The traditional cold start method of catalytic reaction such as CN 101170194A just passes the mixed gas of hydrogen and oxygen into the cathode or anode of the fuel cell, and uses the mixed gas to oxidize and release heat on the catalytic layer to increase the temperature of the battery, but because the mixed gas cannot completely react, although it can The start-up of the PEMFC battery is realized in a certain low temperature range, but when the battery is at a lower ambient temperature, due to the low catalytic heating efficiency, the low-temperature start-up time is too long, and the heat generated by the catalytic reaction during the start-up process is not enough to lower the battery temperature. The temperature rises rapidly above 0°C, so the water generated by catalytic start-up is prone to freezing, which leads to volume expansion and seriously affects the structure and performance of the battery

In addition, the generated ice will cover the micropores of the porous electrode of the battery, so that the mixed gas cannot be completely reacted, and a large amount of mixed gas must be injected during start-up, resulting in excessive fuel consumption and low utilization during the start-up process.

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