Test site requirements for fuel cell products - hydrogen leakage proof_Century Wisdom (Suzhou) Testing Technology Co., Ltd

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Test site requirements for fuel cell products - hydrogen leakage proof

Release time:

2022-12-14 00:00

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I. Requirements for testing sites of general fuel cell products

Hydrogen is a colorless, tasteless, non-toxic, flammable and explosive gas, and fluorine, chlorine, oxygen, carbon monoxide and air mixed with the risk of explosion, therefore, if there is a risk of hydrogen leakage in the production, it is necessary to install one or more sets of hydrogen detector in the workplace, hydrogen content detection work.

Hydrogen detector

Hydrogen detectors are used to monitor the concentration of hydrogen in the environment. Hydrogen fuel cells release hydrogen when they are out of control. A concentration of hydrogen in the air up to 4% can cause an explosion. Hydrogen detectors detect hydrogen and emit an alarm and automatically activate a fan to reduce the concentration, reduce the risk of explosion, and protect property and employees. The exhaust system is linked by hydrogen detector. Only when hydrogen or combustible gas is detected can the exhaust system be linked, rather than running continuously, which will not affect the air conditioning system.

Detector characteristics:

● Continuously detect the concentration of hydrogen and explosive gas in the protected area

● Detection of hydrogen, methane, ethane, CO and other gases

● Automatic linkage exhaust system to eliminate hydrogen and explosive gas

● Reliable, high sensitivity, high stability, high life sensor

● Comes with a screen to display real-time concentration (optional)

● National explosion-proof certification (ATEX certification and UL certification are optional)

Meet the following criteria:

NFPA-2 Technical Standard for Hydrogen Gas

NFPA-69 Standard for Explosion Protection Systems

NFPA-855 Standard for Stationary Energy Storage Systems

Advantages of detector:

● Effective prevention of hydrogen fuel cell or energy storage system explosion

● Reliable, uninterrupted all-weather monitoring and control

● Only when hydrogen is detected can the exhaust system be started. Usually, the exhaust system does not work to reduce the power cost

● Reduce the cost of air conditioning and heating, exhaust system controlled operation

● Protect the safe operation of battery room or energy storage system

Hydrogen detector is usually portable and stationary. Portable and convenient for the staff who frequently go to the site inspection, or the staff who go to the limited/confined space for work, the fixed hydrogen detector is fixed in a place of the workplace, 24 hours non-stop detection of on-site hydrogen content.

Portable hydrogen detector, preheating speed is fast, convenient for staff on-site inspection can be used at will. Imported sensors are adopted, with fast detection speed and accurate monitoring data. The hydrogen concentration on site can be digitally displayed on the display screen in real time. The screen backlight is comfortable and bright, and the staff can check the concentration value at any time. And the Dongri Yingneng portable hydrogen detector menu operation is simple, avoid complex operation, not only save time, but also improve the detection efficiency.

Stationary hydrogen detection alarm is usually composed of hydrogen detection alarm and gas alarm controller. In general, the factory needs to install several fixed hydrogen detection alarms. In order to facilitate management, a gas alarm controller needs to be installed to manage the probes in the factory in a unified manner.

The gas alarm controller does not need to be installed in the operation site. It can be installed in the duty room and other places, and relevant personnel can monitor and control each monitoring point. If the concentration of hydrogen in a monitoring point exceeds the standard, the probe of the monitoring point will send out a sound and light alarm signal. At the same time, the controller will also make an alarm response. The personnel on duty can accurately know the alarm probe through the controller and make the next emergency measures.

Hydrogen detector

In the environment where hydrogen exists, the corresponding hydrogen detector can be set up to detect the concentration of hydrogen gas in the environment in real time. The real-time screen displays gas concentration and alarm. When the device detects that the concentration of gas in the environment exceeds the standard, it will send an alarm sound to inform the personnel in the environment of the scene situation, and transmit the data signal to the personnel in the control room in real time to inform the scene situation remotely. At the same time, the equipment such as fan and exhaust fan can reduce the gas concentration in the environment in real time and purify the surrounding air.

Hydrogen detector Linkage exhaust System (1)

Hydrogen detector Linkage exhaust System (2)

Hydrogen detector linkage exhaust System (3)

Exhaust system:

The exhaust system meets the ventilation and safety requirements of the closed room. It can exhaust air independently or work in tandem with hydrogen detector and combustible gas detector to eliminate flammable gas accumulated in the lithium battery room, so as to ensure the safety of the lithium battery room or energy storage system.

The bellows of the exhaust system come with sliding fixed rings, which are convenient to be installed on the walls of buildings or containers. There are exhaust motors and electric shutters in the fan box.

The exhaust system can be used independently or in conjunction with hydrogen and combustible gas detectors.

Exhaust system characteristics:

● The bellows are wall-mounted, which can be used independently or linked with hydrogen detectors

● External IP54 rated waterproof blinds

● The ventilation system comes with shutters, which are normally closed

● With sliding fixed ring, suitable for various thickness wall and container

● Louver replaceable filter (optional internal and external maintenance)

No spark, no contact, suitable for lithium battery room or flammable gas accumulation area

● Meet the ventilation system specifications

Exhaust system

Ventilation system installation drawing

Requirements for fuel cell vehicle or power system laboratory

At normal temperature and pressure, hydrogen is a very flammable gas, colorless, transparent, odorless, tasteless and insoluble in water. Hydrogen is the least dense gas known in the world, the density of hydrogen is only 1/14 of air, that is, at 0 ℃, a standard atmosphere pressure, the density of hydrogen is 0.0899 g/L.

Based on the above characteristics of hydrogen, in order to ensure hydrogen safety during the powertrain test of fuel cell vehicles, in addition to the top of the laboratory should be equipped with a sensor to detect hydrogen, hydrogen emptying of the powertrain system is also the focus of hydrogen safety, and the risk factor is extremely high in the development and test stage.

The powertrain system of fuel cell vehicle mainly includes driving motor, reactor system, DCDC system, high pressure hydrogen storage system, control unit and power battery unit.

The power system with hydrogen leakage risk is mainly concentrated in the hydrogen supply system, the TPRD on the hydrogen storage bottle, the repair port Service port in the hydrogen supply system, the Regulator vent pipe on the pressure reducing valve and the empty pipeline in the fuel cell system, according to the different hydrogen pressure, set high and low pressure empty system, Ensure the safety of test and personnel.

Emptying diagram

In order to improve the utilization rate of hydrogen, hydrogen cycle scheme is generally adopted in fuel cell system operation. With the increase of running time, the generated water at the anode side of the reactor will not be free, leading to the reactor water blocking, which will affect the reactor performance. At present, the conventional treatment is to discharge hydrogen regularly, use pressure to Purge hydrogen and water drainage, also known as purge hydrogen. Intermittent purge method was used to solve the problem of water in the reactor, but the resulting problem was that the hydrogen concentration in the tail exhaust gas increased sharply, and the hydrogen air mixture could not be fully mixed in a short time. During the development and test stage of the system, the hydrogen concentration in the 100mm airflow center line of the tail exhaust outlet was highly likely to exceed the 75%LFL requirement, which was a potential safety hazard. Therefore, the powertrain system in the test stage needs to conduct secondary treatment of hydrogen tail gas and discharge it after meeting the standards. The laboratory has a tail-exhaust treatment system dedicated to fuel cell vehicle testing.

The laboratory is equipped with independent hydrogen supply pipeline, hydrogen venting and tail-off processing system for fuel cell vehicles. With high precision hydrogen consumption measurement unit. The fuel cell vehicle assembly laboratory is equipped with all-wheel-drive bench for powertrain development, performance testing, evaluation and research of fuel cell vehicles to shorten the development cycle of the whole vehicle and powertrain.

The hydrogen venting and tail-discharge processing system for fuel cell vehicles and the hydrogen safety system in the laboratory ensure the absolute safety of the test process. It can be used to test and calibrate 4 drive or 2 drive vehicles at normal temperature, meet the requirements of current European and American standards, and provide technical support for vehicle hydrogen emission performance calibration, energy consumption and driving range test, vehicle dynamic performance and hydrogen consumption performance evaluation.

Fuel cell vehicle or power system EMC darkroom requirements

Hydrogen fuel cell is one of the core power components of new energy vehicles, which is closely related to the driving range, safety performance and EMC performance of the vehicle. How to design and solve the EMC problem of hydrogen fuel cell has become the focus of attention in the industry.

The anechoic chamber equipped with "hydrogen fuel cell engine system" can fully meet the scarce demand of electromagnetic compatibility testing resources for fuel cell engines. The hydrogen supply system can meet the conditions of 100kW fuel cell engine system, equipped with six hydrogen concentration sensors, with automatic alarm, darkroom air volume adjustment and gas shutdown functions.

It is equipped with hydrogen fuel engine test auxiliary facilities (hydrogen, nitrogen, compressed air, ultra-pure water, etc.) to meet the normal operation requirements of hydrogen fuel cell engine assembly. In order to ensure the safety of hydrogen-related tests, an active suction hydrogen leakage detection scheme is innovatively designed. Meanwhile, the darkroom strong exhaust system is equipped and linked with the hydrogen supply valve to further ensure the safety of hydrogen-related tests in the darkroom.

Technical requirements:

Hydrogen-related safety EMC testing capability:

In order to ensure the safety of the hydrogen fuel engine assembly test, the hydrogen storage compartment equipped with explosion-proof walls shall be more than 10m away from the main building. The storage compartment shall be equipped with an online monitoring system for hydrogen, oxygen and other gas concentrations, as well as smoke alarms and explosion-proof cameras. In order to detect hydrogen concentration quickly and not reduce the performance of the darkroom, a pump suction method was innovatively adopted to detect hydrogen concentration and a flame alarm detector was set in the darkroom. An automatic control system is adopted to collect and output all the above monitoring signals at different levels, and link the strong exhaust fan and the emergency cut-off valve. In case of emergency, the hydrogen supply can be automatically cut off and the dark room can be forcibly discharged, so as to reduce the possibility of safety accidents as much as possible.

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