As you will be aware, the issue of fire suppression of Lithium-ion battery fires is a significant one for both battery manufacturers and OEM automotive firms.
The above problem has been the subject of both research and extravagant claims by most of the world’s fire suppression system manufacturers, many of whom have held themselves out as having developed effective fire suppression systems for electric vehicles. However, the reality is that no one has been able to prove the efficacy of their systems; and this is because fire suppression systems with verified effectiveness do not as yet exist. One potentially promising approach is the deployment of aerosol fire suppression systems and various auto OEMs have conducted tests with aerosols. The issue is that notwithstanding different external designs and modern signalling systems, all current aerosols have chemical composition created more than 20 years ago, when the problem of suppressing automotive battery fires did not yet exist.
This year Impulse Storm Ltd established a laboratory to develop aerosol systems specifically for vehicles. It is staffed by several specialists with relevant knowledge acquired over decades. The main difference in the new aerosol system they have created is the alteration of the chemical and physical properties of the aerosol component, which can then be used in any packaging and with any signalling system.
Key Differences Between the New Impulse Storm (IS) Aerosol and that of the global leaders in Aerosol Systems are:
1. The amount of IS aerosol needed to extinguish each cubic meter of space is 25 grams, roughly a third to a quarter of that needed by the current generation of aerosols. This allows for a four-fold reduction in the size and weight of the new extinguisher and also substantially reduces the operating temperature of the aerosol generator. This feature significantly enhances the safety and reliability of the aerosol.
2. IS aerosol is pliable, which completely eliminates integrity issues arising from vehicle vibration and impact. No other aerosol offers this property.
3. Due to the high degree of homogenization of the aerosol, its hygroscopicity is significantly lower than any other aerosol.
4. The pH level of the new aerosol fluctuates around 7.0, mitigating any risk of corrosion.
Based on our current assumptions as to the configuration of fire prevention and/or suppression systems for electric vehicles, we believe that the main problem to address is to tackle the release of flammable gases before ignition; then if this fails, ideally the system needs also to be able to suppress any fire transitioning to a stage where it becomes uncontrollable. To cope with these two very different problems, we envisage that two different formulations of the aerosol would be incorporated into the IS system, each with its own chemical composition, already confirmed through testing in the IS laboratory. Note that because IS system is several times smaller and lighter than any other system, the form factor should not be a problem.
Firstly, sensors would detect an incipient problem with the battery’s stability/gas emission, and if detected would trigger the deployment of the first aerosol, which would act as a source of neutral gas for long-term ventilation of the battery pack container. This is achievable because the IS aerosol generator of neutral gas can operate for up to 30 minutes, delivering gas at minimal temperature, with minimal solid particle content, and at a pH level of 7.0. Secondly, if thermal runaway occurs, the second aerosol would deploy as a rapid fire suppression medium, while still allowing the first aerosol to continue with the ongoing dispersion of flammable gasses, in order to prevent reignition.