Fuel cell system and purging starting method thereof

Abstract

The invention discloses a fuel cell system and a purging starting method thereof. The fuel cell system comprises an electric pile, a hydrogen supply unit, a hydrogen proportional valve, an ejector, a gas-water separator, an exhaust valve, a drain valve, a water pump, a radiator, a CVM voltage monitoring module, a pressure sensor, an outlet temperature sensor and an inlet temperature sensor. The starting purging method comprises the following steps: after the fuel cell system receives a starting instruction, detecting the temperature of a cooling liquid outlet and the temperature of a cooling liquid inlet of a galvanic pile, and if the temperature of the cooling liquid outlet and the temperature of the cooling liquid inlet are both greater than a specified temperature threshold, enabling the fuel cell system to enter a normal-temperature starting process; otherwise, the fuel cell system enters a cold start process. By reducing the hydrogen waste, the hydrogen-air interface of the anode is prevented from appearing or the existence time is shortened, so that the hydrogen utilization rate is improved, and the service life of the galvanic pile is ensured.

Description

technical field [0001] The invention relates to the technical field of fuel cells, in particular to a fuel cell system and a method for starting and purging the same. Background technique [0002] Hydrogen fuel, a clean, non-polluting renewable energy, is being used in more and more fields. Hydrogen fuel cells can convert hydrogen into electricity and heat. When working, hydrogen fuel cells not only have high power generation efficiency, but also have the advantages of low noise and no pollution. [0003] During the start-up process of the fuel cell, the anode should be purged with hydrogen to discharge impurity gas, so that the anode cavity is covered with a certain pressure of hydrogen. [0004] At present, the anode purging during the startup process of the fuel cell system is not distinguished for different working conditions. Generally, the same purging mode is used, which not only causes unnecessary waste of hydrogen, but also has no measures to avoid the generation o...

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Problems solved by technology

[0004] At present, the anode purge during the start-up process of the fuel cell system is not differentiated for different working conditions. Generally, the same purge mode is used, which not only causes unnecessary hydrogen waste, but also does not have measures to avoid the anode generation or the long-term existence of the hydrogen-air interface. There is a risk of reducing stack life

[0005] The existing technical solutions generally open the exhaust valve first, then control the hydrogen proportional valve or the hydrogen injection valve to fill in hydrogen, and carry out quantitative and regular hydrogen purge on the anode of the stack, without considering the difference between the positive or negative pressure of the anode before starting , and the effect of the presence of oxygen in the anode chamber

In addition, the effectiveness of purging during cold start is not considered. When the exhaust pipe or valve is frozen and blocked, effective purging cannot be carried out.

[0006] The existing technology has the following defects and deficiencies: 1. If the anode is filled with hydrogen before the start of the fuel cell system (the fuel cell system is shut down soon), then purging will cause hydrogen waste; 2. If the anode is under negative pressure before the fuel cell system is started, If the exhaust valve is opened first, the outside air will be sucked into the anode to form a hydrogen-air interface, which will accelerate the corrosion of the carbon carrier material; 3. If there is oxygen in the anode before the fuel cell system is started, it should be purged quickly to minimize the anode hydrogen-air interface Existence time; 4. If the exhaust pipeline or valve is frozen and blocked, corresponding measures should be taken

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