Fuel cell system and low-temperature starting control method thereof

Abstract

The invention relates to a fuel cell system and a low-temperature starting control method thereof. In the low-temperature starting process, the voltage of a galvanic pile is controlled in a staged mode through an electronic load, the output current of the galvanic pile is controlled in a staged mode, a drying film can absorb generated water easily, the performance of the galvanic pile is improved, and the heat yield of the galvanic pile is further increased by controlling the voltage of the galvanic pile. The galvanic pile is heated, and pore spaces of the catalyst layer and the diffusion layer are fully utilized; besides, the generated electric energy is directly supplied to the PTC to heat the cooling liquid, and in order to prevent the PTC from being overheated and discontinuously starting a water pump, the opening degree of a thermostat is controlled to enable the fuel cell system to work in a small cycle, and the PTC directly heats the cooling liquid. Compared with the prior art, quick start of the fuel cell in a low-temperature environment is facilitated, the low-temperature starting success rate of the fuel cell is improved, and the service life of the fuel cell at a low temperature is prolonged.

Description

technical field [0001] The invention relates to the technical field of fuel cells, in particular to a fuel cell system and a low-temperature start-up control method thereof. Background technique [0002] A proton exchange membrane fuel cell is a power generation device that directly converts the chemical energy of fuel (such as hydrogen) into electrical energy. After the fuel cell system is running with sufficient fuel and oxidant (air or oxygen) supplied to the stack, the fuel cell can continuously output electric energy and generate product water and heat. Through proper system thermal management and gas supply optimization, it can Make the fuel cell run well output. In addition, fuel cells have the advantages of high efficiency, low noise, and no emissions. They are considered to be one of the ideal clean and efficient power generation devices and can be widely used in automotive power systems. [0003] However, at low temperature (<0°C), the water generated by the f...

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Problems solved by technology

[0004] Although high current is conducive to the heat generation and temperature rise of the stack and the heating rate of the stack, high current needs to consume a lot of gas, and the large amount of water produced is more likely to freeze between the catalytic layer and the diffusion layer or in the pores of the diffusion layer, which cannot be well use of pore space

In addition, at low temperature, the performance of the fuel cell is not good, and it is easy to cause reverse polarity by directly pulling a large current, which is not conducive to low temperature start-up. Therefore, the control strategy should be optimized to make full use of the void space and increase heat production and temperature rise

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