To help with the prevention of lithium battery fires, two companies have developed differing methods for controlling these hazards.
Soteria has developed a novel approach to cell manufacturing by replacing the unstable plastic separator with a thermally stable, reinforced, non-woven separator. Secondly, the current collectors are replaced with metallised films with enough metal to run the battery but not to support the intense current density involved in thermal runaway. These technologies isolate the internal short and enable the rest of the cell to continue functioning without the risk of further fire or explosion.
In 2023, Fike released a solution named ‘Fike Blue’ that has repeatably been shown to effectively cool cells while also suppressing the fire – this solution is a liquid that fills the battery module and absorbs the heat from the battery cells.
Fire safety
According to Fike, BESS manufacturers, owners and authorities having jurisdiction must understand that thermal runaway is not a problem solved with traditional fire protection methods; this is a problem solved with thermal management.
Global standards often suggest controlling the fire and chemical reaction with methods such as water, aerosols and gaseous agents; however, testing at the Fike Research and Innovation Campus has repeatedly shown that while these solutions may be effective at reducing or suppressing the fire, they do little to stop the chemical reaction, and the chance of re-ignition is high.
Another effect of thermal runaway that must be addressed is the off-gassing of flammable mixtures including carbon monoxide, hydrogen, methane and more. The UL 9540A test requires that any off-gassing resulting from malfunctioning batteries is maintained under 25% of LFL (lower flammability limit) to eliminate the risk of ignition. Some methods of achieving this:
- exhaust ventilation – ventilation systems are necessary to periodically purge the environment of any potential off-gassing and provide an extra layer of protection to ensure LFL is maintained below 25%
- explosion venting – in scenarios where reliable exhaust ventilation isn’t possible or when protection against the worst-case scenario is necessary, explosion vents may be used to relieve a deflagration’s pressure and flames to a safe location
- gas detection – as an added precaution, gas detectors may be used to identify off-gassing between the activation of exhaust vents or the signs of thermal runaway in its very early stages.
The company says thermal management solutions such as its Fike Blue are ideal in reducing the amount of off-gassing. It says the fewer cells that are affected by thermal runaway, the less combustible gas that is produced.
