There is no doubt that electric car battery fires are dangerous. They're not at all as common as gasoline-powered car fires but still they happen. In fact, electric cars are 10 times less likely to self-ignite compared to ICE vehicles. But when a fire does occur - it will be very difficult to extinguish.
Our colleagues at Carbuzz discovered two patents filed with the US Patent Office by Audi that address the issue of battery fires. The solution that Audi offers seems simple and quite easy to implement.
The first patent is for a new battery control system. This solution introduces sensors mounted in individual battery cells. Each cell is monitored continuously and if at any point it is outside the nominal temperature range, it can be turned off and disconnected from the entire battery. It prevents thermal runaway resulting in fire and some cells can be shut down if needed.
The second patent discusses what happens if thermal runaway occurs and cell death is no longer possible. If the control system detects that the temperature in individual cells or the number of cells indicates thermal runaway, the battery pack is flooded with fire extinguishing powder which does not allow the fire to survive. Another interesting solution is an external feed line for powder that firefighters can connect to which means effective fire control and potentially a repairable vehicle afterwards.
Simple solutions are always the hardest to find, which are clearly known for staring us in the face. The control unit has access to each of the battery cells and can monitor and turn on or each is individually complicated. This makes a lot of sense and would have other benefits, not just fire prevention.
Killing individual cells that are found to be less efficient can help them recover - this solution has already been looked at by StoreDot. Individual cell control can mean multiple chemical cells in one battery pack - some offer faster charging and some offer longer range. This is a solution that Our Next Energy has already tested in its EV batteries.
The battery progress is relentless, everything happens so fast that it can sometimes be hard to keep up. While most people still think an EV can drive around 200 km and is better at baking than actually driving, the reality is quite different.