Cell Guard offers improved monitoring of battery pack condition

Cell Guard sensor (Photo: Metis Engineering)

Metis Engineering, which is based in Bristol, UK, has introduced Cell Guard, a new battery pack safety sensor which is said to overcome many of the limitations of existing battery management systems. The sensor can be used in electric vehicles and battery energy storage systems.

Cell Guard can monitor a series of battery environment factors, including presence of VOCs, pressure change, humidity, water ingress and dew point. An optional accelerometer can be used to measure shock load on the li-ion pack of up to 24 G, essentially recording any mechanical stress on cells and packs.

In addition, the sensors are also capable of detecting cell venting, a situation which can indicate thermal runaway within the battery pack. The system can cut the affected battery pack out of the power loop, giving it an opportunity to cool down.

While the sensors offer improved safety features, they also provide data outlining the state of health of the battery pack. This offers insight into capacity and how the battery pack has been managed (charging rate, frequency, etc.) so as to determine the value of the battery pack on the second-life market.

Data is sent via a configurable CAN interface to a local control unit, such as the vehicle ECU. Should battery condition fall outside set parameters, this can trigger a warning for the driver/operator.

Jim Holdsworth, MD at Metis Engineering, said: “Cell Guard not only greatly improves battery health and longevity [but] it also provides consumers with valuable and detailed information on used EV battery condition, which is something that is currently lacking and would transform the market.”

Certified to ISO Automotive standards, more than 100 Cell Guard sensors can be daisy chained for larger battery storage system monitoring.