The Effectiveness of Using Hydrogen Sensor to Detect Thermal Runaway Mostly Recommended

Potential possibilities can be discovered in advance through various sensor detections for situations that may occur due to thermal runaway. The first is a humidity sensor. Excessive humidity will produce condensation, which will increase the risk of short circuits and cause failures, including thermal runaway. Condensation can also cause corrosion and create small leaks in the battery pack's cooling system.

Since condensation can hydrolyze, producing dangerous levels of hydrogen gas, using a hydrogen sensor is another option. In fact, once the thermal runaway effect is about to occur, a large number of characteristic gases such as hydrogen, carbon monoxide, and other small molecular hydrocarbons will be generated internally and will be released through the vents. Most of these exhaust gases are flammable and can burn or explode under arc or spark conditions.

Generally speaking, gas sensors have significant advantages in detecting thermal runaways because they have the benefits of response time of less than 1 to 8 seconds, low latency, and a strong signal-to-noise ratio. In particular, carbon monoxide and hydrogen are produced early in the battery decomposition process, and the concentrations released during the exhaust process are much higher than in the background, making detection relatively simple. Detecting smoke is also a method, but the disadvantage is that it may not occur at all or may appear late in the process.

Since hydrogen has the fastest diffusion speed among these characteristic gases, it is pretty reliable to use it as an early warning of thermal runaway. Studies have pointed out that according to several reports, simulation tests of hydrogen detection in lithium tram battery packs show that according to its diffusion behavior when hydrogen sensors are installed in an appropriate number and location, once hydrogen is detected, the power supply is immediately cut off. The battery's surface temperature will tend to decrease, and thermal runaway will be avoided. Therefore, the test and simulation results confirm that installing hydrogen sensors is an effective way to provide early warning of thermal runaway.

In addition to gas sensors, aerosol sensors can use light scattering to identify air particles in the exhaust gas and provide immediate thermal runaway warnings. The pressure sensor module, which combines a micro-electromechanical system and a dedicated ASIC, can detect transient pressure changes in the battery pack of lithium electric vehicles and also has an early warning effect.



References

• Forbes Technology Council, 2023-08-10, Sarah Martin, How Sensor Technologies Safeguard Electric Vehicles
• Process Safety and Environment Protection Volume 175, 2023-07, Nawei Luy and five others, Hydrogen gas diffusion behavior under fault conditions and detector installation optimization of electric vehicles
• Power Electronic News, 2023-09-27, Stefano Lovati, MEMS Hydrogen Sensor Detects BMS Thermal Runaway