Electric vehicles, and the Fire Brigade.
Discussion
With the rise of EV's, how will the fire brigade have to adapt to fight car fires?
Currently they turn up pour water on it, and the fire is out, all being well. But this isn't going to work with electric cars. Will there have to be special engines, with a chemical foam, or something along those lines. And what about like on The Grand Tour, that kept catching fire for 3 days after the accident, will cars have to go to a safe area until it is confirmed they are no longer a danger.
I know some EV's must have already caught fire in the UK, but can find nothing about how they were dealt with. I wonder what the Fire Brigade think about the extra dangers this poses.
Currently they turn up pour water on it, and the fire is out, all being well. But this isn't going to work with electric cars. Will there have to be special engines, with a chemical foam, or something along those lines. And what about like on The Grand Tour, that kept catching fire for 3 days after the accident, will cars have to go to a safe area until it is confirmed they are no longer a danger.
I know some EV's must have already caught fire in the UK, but can find nothing about how they were dealt with. I wonder what the Fire Brigade think about the extra dangers this poses.
Water is fine, it just takes more of it than in a conventional car fire. It’s also important to understand the characteristics of a lithium battery fire - especially the likelihood of it flaring up again.
Knowing where the high power cabling runs is important too.
Other than that, it’s pretty much just a normal car fire.
Knowing where the high power cabling runs is important too.
Other than that, it’s pretty much just a normal car fire.
No real difference to approaching any other vehicle incident.
http://www.ukro.org/News-Stories/New-EV-Workshop-H...
They have mobile data terminals, which they routinely consult at a scene to check manufacturers' guidance on how to disable airbags, where to cut or prise open and other hazards for the specific vehicles involved.
Instructional videos on youtube:
https://www.youtube.com/watch?v=hG0Vvv16mV4
https://www.youtube.com/watch?v=ntK3rvVl2Qw
http://www.ukro.org/News-Stories/New-EV-Workshop-H...
They have mobile data terminals, which they routinely consult at a scene to check manufacturers' guidance on how to disable airbags, where to cut or prise open and other hazards for the specific vehicles involved.
Instructional videos on youtube:
https://www.youtube.com/watch?v=hG0Vvv16mV4
https://www.youtube.com/watch?v=ntK3rvVl2Qw
charltjr said:
Water is fine, it just takes more of it than in a conventional car fire. It’s also important to understand the characteristics of a lithium battery fire - especially the likelihood of it flaring up again.
Knowing where the high power cabling runs is important too.
Other than that, it’s pretty much just a normal car fire.
you think there'd be a standardised location for a kill switch, like a firemans killswitch for neon shop signs, but these ideas generally require the bad things to happen, normally repeatedly, before someone has the bright idea.Knowing where the high power cabling runs is important too.
Other than that, it’s pretty much just a normal car fire.
How easy would it be to purify the water in the fire truck, such that its non-conductive?
In fact it is better to make the water more conductive as this causes the battery to discharge safely, providing there is enough water for long enough time. This is not practical for an automotive EV sized battery but for portable types the approved method to safe damaged batteries is to place them in salt water for a period of weeks.
GT6k said:
In fact it is better to make the water more conductive as this causes the battery to discharge safely, providing there is enough water for long enough time. This is not practical for an automotive EV sized battery but for portable types the approved method to safe damaged batteries is to place them in salt water for a period of weeks.
I imagine targeting the batteries and not getting any on the ~400v power lines might be a challenge though. Non conductive water would have a cooling effect which is the immediate need.worth noting a few things:
1) EV batteries are completely isolated from the vehicle chassis. Neither HV DC+ or DC- are connected to anything but the powertrain systems. On most EVs a real time isometer monitors the insulation resistance between the chassis and those lines, and should it fall below around 100Kohm, the battery contactors will be opened. Because neither line is earthed, you would have to touch TWO wires to get a shock, touching a single wire would not shock you (but it would cause the isometer to trip the battery contactors to "safe")
2) All EV batteries are protected behind contactors that are powered by the vehicles 12v system. Loss of that voltage would automatically isolate the battery. On a modern car, any impact big enough to fire any of the SRS (Supplementary Restraint System ie airbags etc) also disconnects the LV battery, and effectively forces the contactors open regardless of what is being demanded of them by the control system. Contactors are monitored in real time for things like contact welding etc
3) In addition, most EVs also have a one time use pyrotechnic fuse within the battery. Triggered by a valid "Crash signal" (ie any other SRS system reaching its trip threshold) it is exploded and physically breaks the battery string, regardless of the output contactor status
4) EVs have their HV looms carefully routed (and coloured bright orange, and protected by "trip on opening" connectors) to avoid crumple zones and pinch points. An accident large enough to result in loom (or battery) damage will almost certainly have caused a battery disconnect, either via the normal contactors or via the pyrotechnic fuse.
So, given an accident or fire, the system should not expose any live connectors to persons in the vicinity automatically, and the under-bonnet manual SDS (Service Disconnect Switch) is really just an additional extra layer of safety, that is actually primarily designed to prevent the system from being powered back up unexpectedly (ie it takes a manual intervention to allow the battery contactors to close, it cannot be done via just software etc)
1) EV batteries are completely isolated from the vehicle chassis. Neither HV DC+ or DC- are connected to anything but the powertrain systems. On most EVs a real time isometer monitors the insulation resistance between the chassis and those lines, and should it fall below around 100Kohm, the battery contactors will be opened. Because neither line is earthed, you would have to touch TWO wires to get a shock, touching a single wire would not shock you (but it would cause the isometer to trip the battery contactors to "safe")
2) All EV batteries are protected behind contactors that are powered by the vehicles 12v system. Loss of that voltage would automatically isolate the battery. On a modern car, any impact big enough to fire any of the SRS (Supplementary Restraint System ie airbags etc) also disconnects the LV battery, and effectively forces the contactors open regardless of what is being demanded of them by the control system. Contactors are monitored in real time for things like contact welding etc
3) In addition, most EVs also have a one time use pyrotechnic fuse within the battery. Triggered by a valid "Crash signal" (ie any other SRS system reaching its trip threshold) it is exploded and physically breaks the battery string, regardless of the output contactor status
4) EVs have their HV looms carefully routed (and coloured bright orange, and protected by "trip on opening" connectors) to avoid crumple zones and pinch points. An accident large enough to result in loom (or battery) damage will almost certainly have caused a battery disconnect, either via the normal contactors or via the pyrotechnic fuse.
So, given an accident or fire, the system should not expose any live connectors to persons in the vicinity automatically, and the under-bonnet manual SDS (Service Disconnect Switch) is really just an additional extra layer of safety, that is actually primarily designed to prevent the system from being powered back up unexpectedly (ie it takes a manual intervention to allow the battery contactors to close, it cannot be done via just software etc)
How the German Fire fighters do it....
They said:
Yesterday an electric car started smoking in a showroom. This car was immersed in a tank of water, because normal extinguishing in this car was difficult. We've had a lot of comments and questions on yesterday afternoon's post. That's why we like to tell you a little bit more!
Extinguishing an electric car requires a lot of water for a longer period of time, partly because the battery packs are difficult to reach and the fire is burning from cell to cell. That's why there has been chosen to immerse in a tank of water where the car stays in for a long time. There are always unsafe substances produced by fires, and that is also the case with such a fire. This polluted effluent is subsequently removed by a specialized company. Together with Brandweer Nederland and our partners, we continue to prepare for new technological developments!
Extinguishing an electric car requires a lot of water for a longer period of time, partly because the battery packs are difficult to reach and the fire is burning from cell to cell. That's why there has been chosen to immerse in a tank of water where the car stays in for a long time. There are always unsafe substances produced by fires, and that is also the case with such a fire. This polluted effluent is subsequently removed by a specialized company. Together with Brandweer Nederland and our partners, we continue to prepare for new technological developments!
The issue with EV’s and fire is how volatile li-ion is. Just piercing a single cell can cause it to combust. And then it’s a chain reaction if you have 5000 of them in the battery pack.
For all the volatility of petrol it has actually proven to be pretty robust in lots of road traffic accidents and it’s comparatively rare for a car to explode in flames due to the petrol tank being ruptured.
For all the volatility of petrol it has actually proven to be pretty robust in lots of road traffic accidents and it’s comparatively rare for a car to explode in flames due to the petrol tank being ruptured.
Had a fairly big collision in a 330e last year with airbags deployed etc so I obviously got out the car and stayed away from it.
The fire brigade arrived, mainly to cut the other person out of her vehicle but they also did some checks on my car when they found out it was hybrid. As mentioned above they had guidance on what they were looking for via a tablet.
The recovery company turned up but did not seem keen on loading it but I don’t really think they knew what to do. The first waited for another colleague to arrive who put a load of danger stickers on it warning about high voltage and put some planks of wood to put under it for loading.
The fire brigade arrived, mainly to cut the other person out of her vehicle but they also did some checks on my car when they found out it was hybrid. As mentioned above they had guidance on what they were looking for via a tablet.
The recovery company turned up but did not seem keen on loading it but I don’t really think they knew what to do. The first waited for another colleague to arrive who put a load of danger stickers on it warning about high voltage and put some planks of wood to put under it for loading.
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