Honeywell BES-Series
The Battery Safety Electrolyte Sensor (BES) enables early and reliable detection of thermal runaways in lithium-ion batteries used in electric vehicles.
Description
Using an advanced and patented change rate algorithm, the BES detects battery electrolyte vapor, which is typically released during the first vent phase, as well as hydrogen and carbon monoxide gases released during thermal runaway. The ability to detect first vent provides an important early warning of potential thermal runaways in lithium-ion battery packs. This proactive early detection enables timely and appropriate corrective action, significantly reducing the risk of thermal runaway. BES uses a patented, advanced rate-of-change algorithm designed to detect significant changes in the concentration of target gases within a sealed battery pack.
Operating principle
Various gases are released during thermal runaway. In the initial phase, a high concentration of electrolyte vapor escapes from the cell. These include gases such as ethylene carbonate (EC), diethylene carbonate (DEC), ethyl methyl carbonate (EMC), and dimethyl carbonate (DMC), among others.
As the event progresses to an explosion, there is an increase in H2 and CO. The BES series sensor is equipped with a siloxane-resistant metal oxide semiconductor sensor that is highly sensitive to electrolyte vapors, H2, and CO. Due to its sensitivity to multiple target gases, the BES sensor ensures reliable and early detection compared to conventional gas sensors.
The BES sensor is equipped with a patented built-in rate-of-change algorithm that triggers an alarm as soon as one of the measured gases is detected.
- Detects electrolytes released during initial venting (before thermal runaway)
- Responds to H2 and CO released during thermal runaway
- Patented alarm algorithm ensures critical alarms are not missed
- Resistant to siloxane-containing contaminants
- Automotive product with CAN 2.0B output with diagnostic functions
| Measuring gases | Electrolyte vapor, H², CO |
| Measured temperature | -40°C to 125°C |
| Pressure range | 60 kPa to 165 kPa |
| Ambient temperature | -40°C to 85°C |
| Humidity range | 0 to 90 %RH |
| Protection class | IP3X |
| Response time | < 5 seconds |
| Service life | 5 years with a siloxane exposure of 570 ppb |
Pressure sensors in the application
