helium leak detector in hydrogen fuel cells of new energy vehicles

Helium mass spectrometer leak detector in hydrogen fuel cells of new energy vehicles of application

A hydrogen fuel cell is a power generation device that directly converts the chemical energy carried by its own hydrogen fuel and oxidant into electrical energy through electrochemical reactions. It has the advantages of high energy conversion efficiency, high energy density, low vibration noise, and zero emissions. In addition, hydrogen is a renewable energy source that can be obtained through green energy sources such as solar energy, wind energy, and bioenergy. It is now widely used in the new energy vehicle industry. Therefore, the sealing performance of hydrogen fuel cell devices is closely related to personnel and equipment safety. At this time, helium mass spectrometer leak detectors have emerged, which have high sensitivity, short response time, and are non-toxic and non-destructive. They have been widely used in many fields such as aviation, aerospace, nuclear power, instrumentation, food, chemical industry, machinery, etc.

(New Energy Power Battery)

The new helium mass spectrometer leak detector is a gas tightness detection instrument made using helium gas as the leak gas, based on the principles of mass spectrometry. The mass spectrometry chamber mainly consists of an ion source, analyzer, collector, cold cathode ionization gauge, exhaust system, and electrical components. The electrons emitted by the filament in the mass spectrometry room oscillate back and forth inside the room, and collide with the indoor gas and helium gas entering the room through the leak hole to ionize them into positive ions. These helium ions enter the magnetic field under the action of an accelerating electric field, and are deflected by the Lorentz force, forming a circular arc orbit. Changing the acceleration voltage can allow ions of different masses to reach the receiving electrode through the magnetic field and receiving slit for detection. The components to be inspected in new energy vehicles with hydrogen fuel cells as engines mainly include high-pressure hydrogen storage tanks, hydrogen fuel cell stacks, and hydrogen supply pipelines. The high-pressure hydrogen storage tank for new energy vehicles has a capacity of over 100 liters, the hydrogen fuel cell stack has a capacity of tens of liters, and the hydrogen supply pipeline is more than ten meters long, so the detection volume is relatively small. Therefore, the helium mass spectrometer leak detector chooses the helium injection method for leak detection. When using the helium spraying method, it should be noted that helium is a lightweight inert gas that will automatically rise after spraying. To accurately spray helium at the location of the leak, it should be sprayed from top to bottom and from near to far, in order to avoid the possibility of helium being sucked into the leak above when spraying below, making it difficult to determine the location of the leak.

(Schematic diagram of helium mass spectrometer leak detector)

The specific application of the helium spray method for detection will be explained below:

1. Before vacuuming the hydrogen storage tank, hydrogen fuel cell stack, and hydrogen supply pipeline as the components to be inspected, the interior should be purged and dried. The drying temperature and time should meet the requirements, with a temperature set at 50 ℃ and a time set at 3 hours;

2. Start the vacuum pump to evacuate. If it is necessary to improve the leak detection efficiency and time, a mechanical pump can be used for vacuum pre pumping;

3. When the pressure is less than 10Pa, connect the high-pressure hydrogen storage tank, hydrogen fuel cell stack, and hydrogen supply pipeline to the helium mass spectrometer leak detector respectively;

4. In areas where there may be leaks in high-pressure hydrogen storage tanks, hydrogen fuel cell stacks, and hydrogen supply pipelines (such as sealed joints, exhaust valves, instrument pipes, welds, etc.), helium is sprayed with a spray gun for detection. The observation results show that if there is a leak in a certain part of the inspected component, when helium is sprayed onto the leak, it will be immediately sucked into the vacuum system and diffused into the mass spectrometry chamber, and the output of the helium mass spectrometer leak detector will immediately respond.

At present, China’s hydrogen fuel cell industry is flourishing, and sealing quality is an important indicator to ensure safe operation and promote application. The helium mass spectrometer leak detector utilizing helium technology is an efficient, fast, and accurate non-destructive testing instrument with unparalleled advantages over other detection methods, providing important guarantees for high-quality sealing of hydrogen fuel cell systems. Our helium mass spectrometer leak detector is among the top in the industry.

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