Battery fire in electric cars after a collision

I have been reading about lithium battery fires in cars. Apparently there is a problem with extinguishing car battery fires which can restart with no warning hours or evan days after an incident. How much information is given to electric vehicle owners about such problems especialy hybrid vehicles. Although the number of battery powered vehicles catching fire is low it is higher than a petrol or diesel powered vehicles. I saw a small battery for a drill burst into fire with a small explosion but that was small fry.

David

I did read that some fire service brigades have a special vehicle with a cover like an upside down skip to drop over an electric car and contain the fire, to dangerous to attempt to extinguish.

Grandson is a Fireman and they have special procedures to deal with electric vehicle battery fires, they can be nasty and certainly not easy to control or extinguish. Many years ago at work we had a Nicad battery for our test equipment suddenly burst into flames on the charging bench, plenty of acrid fumes. The fault turned out to be one of the connecting wires linking the cells had chafed on the metal case and shorted out, when it went there was no stopping it. It must be a nightmare to be involved in an accident with an electric vehicle and potentially the battery pack could ignite, I have a number of Lithium batteries connected to my solar panels for storage of unused electricity, I can store 12 kWh of power, I am aware of their unpredictability for spontaneously igniting so they are located outside of the main house in a corner of our conservatory. Dave W

In Germany there have been three separate incidents of buses catching fire one in an udererground car park. In Sweden their fire brigades have a large skip like container which can hold a car. It has spray cooling and can be filled with water in which it has to be submerged for up to several weeks until safe. Why are we not doing anything in our country and warnings a out correct storage charging etc.

David

The other difficulty is that there is no standard protocol about when or how the batteries are isolated after an accident. Since the voltages are quite high and DC, this is a bit of a problem. Surely the batteries should be required to be isolated if the air bags go off.

John

Wrong way to look at it I think. Over course batteries can catch fire, but are they more or less dangerous than petrol? If battery accidents cause fewer injuries than petrol and diesel then which one requires action?

Don't imagine petrol cars are safe! This 2017 fire in Liverpool destroyed more than 1000 vehicles in a car park, also badly damaged.

Started by a Land Rover...

Dave

Maybe the OP or respondents are not up to speed on developments? Lithium ion batteries have been a fire risk - but far fewer fires than fossil fuelled vehicles. Problems have been known ever since their use was adopted (for mobile phones, for instance). It is nothing new.

However, likely most new cars are now, or soon will be, using Lithium Iron Phosphate chemistry for their batteries now - the older technologies being superseded by these safer, but lower capacity designs. They operate at slightly lower voltage per cell and lower capacity, but do not easily ignite and/or burn.

Only the highest power vehicles - requiring the highest power delivery (of the older chemistries) is being used in the Tesla line-up, for instance.

I think the OP needs to read rather more comprehensively before making a post such as above. If anyone trusts a car salesperson to provide all relevant details, of whatever they are selling, is living in cloud cuckoo land. They are a salesman, rely on sales results for their income commission, and will do all they can to make a sale, any sale.

For me the difference between electric and fuel vehicles are, not everybody has a car, but the population numbers paints a picture over time.
1-Fuel vehicles grew with population growth up too over some years 7 Billion plus(Relative).
2-Electric vehicles start at 7 Billion plus(relative) growth rate, no years to speak of much-This is a huge difference not talked about at all.

Now the one is proven over time while the other is still a promise, and nobody is talking about replacing the batteries at some point, and at a scale to 7 Billion would you even find a battery, and will it still fit.

Vehices are most people 2nd largest cost, so in future could this bancrupt the middle class in debt with this-?

So can they manufacture an electric car if battery on fire(indication of heat-sensors), it drops out of the car, car pushed away, let the coolanrt run, battery handled seperately, The fire might start smallish before it explodes, like the electric car lays an egg..

Edited By Chris Mate on 12/06/2022 00:03:56

Well, technology may be moving towards less dangerous battery chemistry, but there have been many documented cases of apparently spontaneous ignition of current tech. batteries, perhaps the most ironic being that which caused a ship, loaded with expensive vehicles, to sink recently. All that water with which to extinguish a fire, but not that sort of fire... And now, manufacturers advise that these vehicles are not garaged.

If you want to scare yourself - or have a laugh, if you're twisted, like me - search for the instruction manual for first responders, issued by Hyundai. Tesla's manuals are rather coy, and leave a lot unsaid. With perhaps 400V DC around the vehicle, and a crashed vehicle likely still to be 'active' (ie will drive off or move if accelerator accidently depressed), with no indication to those unfamiliar with such vehicles, the dangers should be obvious. So the manuals explain how to find relevant fuses, how to cut (in two places) power cables, how to wait until capacitors have discharged, and so on and so on. I don't think that immersion in water is addressed.

Does anyone know the depth of water that can be driven through by an EV? With floor-level batteries, even fording a small stream could be a worry.

Let's hope that when there's a crash, in the back of beyond, the Good Samaritan, anxious to extract the incapacitated occupant(s) from the burning vehicle (without wishing to watch their immolation or exsanguination, whilst the emergency services arrive) has a library of type-specific manuals to hand, and the stipulated PPE, and the time to read them and don them, before attempting to provide aid.

We need to get a little context and perspective when reading such alarmist media reports. EV fires make a good story because they are new and scary, but in fact are outnumbered daily by petrol and diesel vehicle fires. In fact, there are 300 vehicle fires a day in the UK, killing 100 people a year, and most of them are petrol and diesel. (Source LINK )

In London alone, the fire service reports this:

Vehicle fire data

Data obtained through a Freedom of Information (FOI) request revealed that in 2019 the London Fire Brigade dealt with 54 electric vehicle fires compared with 1,898 petrol and diesel fires.

Vehicle registration numbers from the Department for Transport (DfT) show there are 50,000-plus plug-in cars licensed in the capital out of a total 4.63 million licensed cars.

Looking at the London Fire Brigade data, that would suggest an incident rate of 0.04% for petrol and diesel car fires, while the rate for plug-in vehicle is more than double at 0.1%. So far this year, there have been 1,021 petrol and diesel fires and 27 EV fires in the capital.

Source: LINK

There are also several fires a year at service stations with fuel catching fire. So really, at the moment, there is more to fear from petrol and diesel vehicle fires than EVs, even though EVs are twice as likely to catch fire as petrol/diesel vehicles. That will probably go down as the technology improves and maybe more safety systems are mandated either in fire suppression systems or battery isolators etc.

Lucas electrics strike again!

Correction to my previous post. Immersion is addressed. It's also given as a way of discharging the battery!

Here's a link to one of the manuals I mentioned. For dead-pan humour, it would be hard to beat. Just put yourself in the driver's seat...

**LINK**

There is nothing that cannot be done with a Land Rover!

On a more serious note, what happens when Joe* amateur mechanic/electrician decides to have a play with the internals and/or add a few unapproved accessories to his electric vehicle?

This came to mind as my Land Rover was the last vehicle with which I have any familiarity with the bits under the bonnet. Later cars go back to the dealers for service. However others are not so cowardly/sensible and it is likely that there will be more fires at home, and perhaps including the home, as a result.

Recent house fires blamed on charging batteries ( I believe small batteries ) may be examples of this but as usual no follow up on the initial sensationalised news story to fill in the details of how, what and why.

Pero

* Not his real name.

Although, petrol may be less dangerous than we think, maybe...

One big difference with batteries compared to petrol, diesel, LPG CNG or even hydrogen it is hard to remove the energy source after accident damage. The fluid fuels can be drained, vented or even deliberatly bunt off. If the casing is damaged in a crash they tend to be self emptying. All thesw leave a safe wreck for disposal.
Current EV battery technology is based on thousands of small cells. Failure of one or two of these cess can start a chain reaction throughout the battery. This can hapen some time after the inital damage b=due to isulatio craping under pressure or movment due to thermal cycling (day/night). The protections used in small batteries like laptops and power tools are not really applicable due to the number of cells and currents involved.
The only way to "empty" a damaged battery is to fill the housing with conductive liquid or immerse the whole car in conductive liquid (water with a source of ions eg. salt). This is of course destructive.

The battery packs do have an isolator that is used for servicing / rescue and will also protect against shorts external to the battery pack. On my Plug In Hybrid (Outlander) this is a plug on the top of the underfloor battery pack and is accessed through the rear passenger footwell. It does however need tools to operate it. I carry the required tool in my glove box so in the event of any incident I can isolate it myself.

Robert G8RPI.

In information to emergency responders it warns them not to stand to the front or rear of these vehicles as they can self start and move evan at full power if cables are damaged etc. There is no common isolation for batteries evan in same manufacturer. Some retrofitted systems have batteries fitted in multiple areas and most have a auxiliary 12 volt battery as well. Is there any legislation on using third party or self modified chargers or systems on these cars.

David

This is a good example of a development where 'common-sense' has little to offer! What's needed is careful analysis of the risks and application of necessary mitigations.

Almost a no-brainer if a new technology is safer than what it replaces. The benefit outweighs the hazards. In this case there are serious problems with fossil fuel technology up to and including a climate catastrophe. Common sense fails miserably because climate change is big beyond comprehension, whilst most of us can grasp what happens when a car catches fire. Cars catching fire are exciting on a personal level, but don't make much difference to the world. Climate change does everyone in. Fossil fuels have a second serious global problem which is they don't last forever! Prices are going to rise sharply, and as we've seen this week petrol at £2 a litre is causing significant difficulty on top of rapidly rising gas and electricity prices. EV's offer an alternative, not least they run on clean renewable energy that doesn't depend on foreign imports.

It's not a no-brainer though, because batteries come with new problems. The risks have to be identified, their likelihood established, perhaps by experience, and then mitigated. Again 'common sense' fails, because it's based on experience with internal combustion vehicles. These have been developed over a 140 years and it's natural to assume that what comes next is a petrol car fitted with a battery. Not that simple: EVs eliminate old problems, like a petrol tanker delivering fuel catching fire, but bring new ones requiring fresh analysis and innovative thinking. Nothing new here - all technologies go through the process: early aircraft were the most dangerous form of transportation on the planet, now commercial air-travel is the safest.

Politics intrude into this space, which is a pity because it's really an engineering problem. A big C Conservative believes the best way forward is to minimise government interference and let the market sort out the details. He will only legislate after 'accidents', so the public pays in blood! A socialist might believe EVs should be managed for the public good and heavily regulated from the start, with everything nailed down beforehand. This is liable to cause serious delays and strangle development, ending up with an expensive EV that doesn't work well and is still dangerous. Most customers are small C conservatives: they fear change and would rather everything was left as it is despite clear evidence that change is needed urgently. All these folk are liable to make a mess of technical problems because they let emotion, beliefs and prejudice override the evidence.

Engineers, who are far from perfect when it comes to controlling gut feel, should coldly analyse the ways in which a battery could catch fire and design to mitigate them. Mitigate, not prevent. To benefit from technology humanity has to manage the risks, and risk management is a disciplined skill, not common sense.

Anyone reading this happy to blast allegedly weakling woke snowflakes whilst themselves being terrified of change? The two often go together...

Dave

PS. I hate change: it means something is wrong, and people always suffer as a result. The future always ends badly for individuals, we exist to propagate our genes, so should be careful not make life impossible for our off-spring. The sins of the fathers...

Having recovered dozens of burnt out cars, it's very rare for the fuel tank to be the cause or even site of the fire. Most are caused by electrical faults inside the car setting the plastics alight, or mechanical faults creating extra heat and finally fuel leaks onto hot engines. EVs will still suffer from the first two, but not the third.

An ICE car once alight will burn out quite quickly, and is then just pollution. Once alight it takes real effort to stop them, so it's normally only done to prevent the fire spreading. That's not true of battery EVs. But if we're honest, neither batteries nor fuel tanks are solutions that are particularly safe. We're just so used to the risks of fuel tanks in vehicles that we don't realise they are risks.

Indeed. 100 people a year in the UK are killed by vehicle fires, until recent times exclusively by petrol and diesel vehicles. Did anyone ever panic about doing something about these deadly inflammable IC vehicles? Never. 100 dead people a year is just seen as one of those things that happens and can't be avoided. Nothing to worry about. Get in your car and carry on.

I suppose when the Model T Ford or its British equivalent were first released the horse and carriage drivers would have been having their say about the dangers of these fire breathing new monsters driving about carrying gallons and gallons of inflammable fuel just waiting to explode in carmageddon.

Yes people instinctively hate change -- in a world that is constantly changing by nature. That is one definition of absurdity.

Interesting thread. Lithium batteries can suffer from thermal runaway, where too much current flowing leads to greater heat which leads to more current flowing, which leads to greater heat......

Airlines have emergency procedures to deal with lithium battery fires - we cannot pull over and get out of an aeroplane in flight.......They involve submerging the laptop/cellphone in a bar-box full of iced water, and careful monitoring. This is also why the cabin crew will take it very seriously if your phone drops into the seat mechanism. It can get damaged by the mechanism and go into thermal runaway, which they are very keen to prevent !

Electric cars being still 'live' after an accident is a very good point. If there was a fire, then the throttle position sensor could easily melt and send a 'go' signal to the motor. I consider myself warned.

Electric car batteries should have an emergency cut-out. The battery packs I have seen have a linking busbar between each side of the battery pack. This busbar could have an emergency handle protruding into the internal cabin of the car somewhere, which when pulled would break the busbar and separate the two halves of the battery rendering it relatively safe - certainly against it powering the motor.