Metis Engineering has launched Cell Guard, a new battery safety sensor used for battery health monitoring for electric vehicles (EVs) and energy storage systems (ESS). Cell Guard is a sensor that provides “accurate and detailed information on the health of a lithium-ion battery pack to improve longevity, as well as being capable of detecting cell venting, which is an early sign of catastrophic battery failure that vastly reduces the risk of thermal runaway,” the company says.

Metis says Cell Guard monitors a range of environmental parameters required to ensure that the battery continues to operate in optimum conditions, including VOCs, pressure change, humidity, dew point and, optionally, an accelerometer to record shock loads. This data can be used to crosscheck with other inputs, such as cell temperatures and pressure spikes, to identify cell venting. The sensor relays the data over a configurable CAN interface to a control unit, such as the vehicle’s ECU. This can then raise a warning to alert the driver within seconds that cell venting has occurred. The sensor can also trigger the process to cut the circuit to the battery pack, giving it an opportunity to cool down with the objective of preventing thermal runaway.

Cell Guard’s accelerometer can monitor shock loads up to 24G and impact duration that the battery pack may experience, reducing costly scrappage, the company says. In addition, Cell Guard can monitor the dew point in the battery pack and trigger a warning before condensation settles on the battery terminals, which could lead to shorting and thermal incidents.

Certified to ISO Automotive Standards, Cell Guard is manufactured in the UK.