A hydrogen circulation system and its control method

Abstract

The invention provides a hydrogen circulation system, comprising a hydrogen cylinder, a pressure reducing valve, a stack, a hydrogen circulation pump and a hydrogen ejector, the output end of the hydrogen cylinder is connected with the input end of the pressure reducing valve, and the output end of the pressure reducing valve It is connected with the anode inlet of the stack, the anode outlet of the stack is connected with the input end of the hydrogen circulation pump, and the output end of the hydrogen circulation pump is respectively connected with the input end of the hydrogen ejector and the second pipeline, and the hydrogen ejector The output end of the outlet is connected with the second pipeline, and a butterfly valve is arranged on the fifth pipeline. Beneficial effects of the present invention: In the present invention, the output end of the hydrogen circulation pump is respectively connected with the input end and the second pipe of the hydrogen injector through the fourth pipeline and the fifth pipeline, and when the stack is operated at low power, the butterfly valve is closed, The hydrogen ejector is connected in series with the hydrogen circulation pump, thereby reducing the power consumption of the hydrogen ejector at low flow rates and improving the net efficiency of the system.

Description

technical field [0001] The invention relates to the technical field of hydrogen fuel cells, in particular to a hydrogen circulation system and a control method thereof. Background technique [0002] The fuel cell system consists of an air system, a hydrogen system, a thermal management system, and an electrical system. The air system provides the cathode gas required for the reaction through pressurization and humidification. The hydrogen system provides the anode gas required for the reaction by decompressing the high-pressure gas provided by the hydrogen cylinder. In order to improve the utilization rate of hydrogen, uniform the concentration of exhaust gas in the anode hydrogen to increase the life of the stack, and humidify the reaction gas, it is necessary to re-pump the excess gas after the completion of the reaction into the hydrogen inlet for the reaction. [0003] The pressure of hydrogen entering the stack P1 drops to P2 after passing through the stack. If P2 is d...

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Problems solved by technology

[0004] Generally, the high-power fuel cell system chooses to connect the hydrogen circulation pump and the hydrogen ejector in parallel, and adopts a low-power hydrogen circulation pump. The hydrogen circulation pump works at a low flow rate to provide stable hydrogen circulation. It works to achieve a large circulation volume under the working power of a small hydrogen circulation pump. However, under low flow conditions, the hydrogen ejector is basically unusable, resulting in the inability to achieve the highest hydrogen circulation efficiency.

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