SGX Sensortech — BLD1/BLD2 Battery Leakage Detection Sensors

The BLD1 and BLD2 battery failure sensors from SGX Sensortech can detect a battery failure in electric vehicles and rapidly communicate data about it via a controller area network (CAN) bus.

Placed in the battery enclosure, the BLD1 thermal conductivity gas sensor detects hydrogen gas (H₂), which is generated when the battery overheats. As well as sensing H₂, the BLD2 sensor also detects carbon monoxide (CO) gas which is released during the venting phase which precedes thermal runaway, as pressure in the battery begins to build.

The use of a CO sensor enables battery management systems to provide an even earlier warning than systems using pressure sensors, since pressure build-up during the venting phase is not detectable. This early warning of a dangerous battery malfunction gives passengers additional time to leave the vehicle safely.  

Both the BLD1 and BLD2 sensors are highly sensitive to H₂: they detect concentrations ranging from 0% to 10%. The devices have a response time of less than 1 s, and provide a high-speed 500 kbits/s CAN output signal.

Housed in a watertight enclosure, the sensors use standard automotive four-pin connectors. The BLD1 draws an operating current of just 25 mA, and the BLD2 draws 50 mA.