Safety components of hydrogen supply system

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The protection measures of hydrogen system mainly include safety design of high-pressure hydrogen storage bottle and hydrogen pipeline, and installation of various safety facilities. As shown in the functional block diagram of on-board hydrogen system in the figure below, the hydrogen system safety protection system of fuel cell vehicle is composed of evacuation pipe, safety valve, manual stop valve, one-way valve, overflow valve, temperature sensor, pressure sensor, solenoid valve, etc., and corresponding protection values are set in the monitoring system. In case of abnormal conditions, various monitoring information is transmitted through the hydrogen system controller All kinds of safety facilities should be opened or closed in time to make the fuel cell vehicle in a safe state.


In order to achieve the required driving range of electric vehicles, the whole vehicle uses high-pressure hydrogen, while the fuel cell stack uses low hydrogen pressure. For the safety of on-board hydrogen, the components of compressed hydrogen on-board hydrogen supply system mainly include hydrogenation port, hydrogen cylinder valve, one-way valve, over-flow valve, pressure reducing valve, pressure sensor, pipeline, etc

Hydrogen cylinder: aluminum liner is used for hydrogen cylinder, and the pressure of the cylinder is increased after winding with carbon fiber outside, so as to improve the compressed hydrogen volume and meet many requirements of vehicle hydrogen storage.

Hydrogen cylinder valve: hydrogen is a kind of flammable and explosive dangerous chemicals, its safety is very important, so the function of the cylinder valve is also very important. As shown in Figure 7-20, the bottle valve is integrated with 12V solenoid valve, manual stop valve, fuse valve and temperature sensor. There are four inlets and outlets of the cylinder valve, one of which is PRD outlet (used for venting in case of abnormal conditions). The other inlets and outlets are equipped with hydrogen high-pressure pressure sensors. One inlet and outlet is used for the junction when vehicle hydrogen is used. The remaining inlet and outlet are used as standby and can be sealed with plugs. The function of the fusing valve is to automatically fuse when the temperature around the bottle reaches the set temperature value of the valve, so as to open the bottle valve for pressure relief. These designs fully ensure the safety of hydrogen when used in vehicles.

The way to stabilize the pressure of hydrogen gas at the upstream end is through the pressure reducing valve. In general, fuel cell electric vehicles are equipped with two or more hydrogen pressure reducing valves. Generally, the primary hydrogen pressure reducing valve is installed in the high-pressure hydrogen section. The gas inlet pressure is the gas pressure in the hydrogen storage bottle, and the outlet pressure can be set according to the requirements of different systems, usually between 1 ~ 3Mpa. The function of the second stage hydrogen low pressure reducing valve is to make the final outlet pressure of the system meet the requirements of the fuel cell through mechanical regulation of the outlet gas of the first stage reducing valve. Through two-stage or multi-stage decompression, the outlet pressure can be more stable, safer and meet the use requirements better.