NEO1002A H2-Sensor

H2 sensor system for Li-ion battery monitoring for automotive applications.

Lithium-ion cells can pose great dangers if mechanical damage, water ingress, overcharging or deep discharge (see bottom of page) cause flammable gases to escape and, in the worst case, lead to a fire or explosion.

Our new NEO1002 sensor system detects directly in the battery/high-voltage storage HVS both the hydrogen concentration, reducing and oxidising gases, the gas pressure (pressure increase in case of gas leakage), water leakage and also the battery temperature ("thermal runaway" or thermal runaway).

Most important properties:

• Measuring range: 0-2 vol.% H2 (½ LEL)
• Carrier gases Air
• Measurement signal independent of ambient temperature and pressure
• Detection of "thermal runaway", pressure increase and reducing gases in a battery/accumulator
• Temperature measuring range: -40 to 85 °C
• Pressure range: 0.6 - 2 bar absolute
• Humidity: 0 - 90 % r.h. (non-condensing)
• Response time: t90 < 3 s
• Recovery time: t10 < 3 s
• Signal: CAN 2.0 A/B with 250/500 kbps

You can download technical information by clicking on "Data sheet". Or select "Enquiry" and contact us without obligation.  

If Li-ion cells are overcharged or exposed to high temperatures, the layer structure of the metal oxides breaks down. During this process - which is highly exothermic, i.e. high amounts of energy are released - elemental oxygen is formed. The high thermal energy leads to evaporation of the organic electrolyte liquid, producing highly combustible gases. If the temperature in the cell exceeds the flash point of a gas, then this organic gas ignites and the Li-ion cell burns. As this is a self-reinforcing process, it can lead to thermal runaway and ignite the stored Li atoms (metal fire).

Deep discharging a Li-ion cell can also lead to a fire. Again, the electrolyte liquid decomposes and forms easily combustible gas. Copper ions go into solution from the copper sheet, which is used as a discharge material on the anode side. If such a deeply discharged Li-ion cell is charged, the amount of energy supplied can no longer be stored in chemical energy due to the lack of electrolyte liquid. The charging energy is converted into heat. In addition, the dissolved copper ions deposit as copper needles on the graphite (anode). They can pierce the separator foil and cause a short circuit.

If the current density is too high and the leads melt, reducing and oxidising gases are also produced and can be detected.