By on February 13, 2011

While EVs are slowly, very slowly  – catching on would be exaggerated, people are starting to think about the finer points. For instance: Electric vehicles and plug-in hybrids are powered by high-voltage batteries of up to 400 volts, possibly more. What happens if one crashes and first responders have to attack the vehicle with power cutters? Will the responder die from electrical shock? This is a hot topic amongst first responders, right up there with dealing with explosive airbags, belt tensioners and other surprises.

Currently, each manufacturer publishes an individual Emergency Response Guide that tells them where to cut and where not. Easy to forget, especially with the paucity of EVs on the roads.

German automotive supplier Continental has developed a sensor unit for electric and plug-in hybrid vehicles which will immediately shut off the high-voltage battery in the event of a collision. Well, not exactly:

“The evSAT acceleration sensor is active in charge mode. It detects an accident and passes this information on to the battery management system which then shuts off the high-voltage battery,” Ibtimes was told by Dr. Axel Gesell, Senior Manager Platform Development Sensors & Satellites of Continental’s Chassis & Safety Division. “The major benefit of our product is that it prevents fire and rescue service personnel sustaining high-voltage injuries when coming into contact with vehicle metal parts or if they have to cut through the vehicle to recover accident victims.”

But what if the battery management system is dead already? And how do you know that the power is on or off?  Current manufacturers of EVs have similar systems, one way or the other. None are perfect. According to greencarreports, automakers all tend to give variations of the same answer: “We’ve followed all the usual design standards on this new vehicle, and we’ll be offering training to national responder organizations that is disseminated down to their various members.”

One thing is for sure: EMS personnel will approach crashed EVs very carefully.  Which may provide a niche for a certain market segment: Drug dealers. Police officers will search an EV with great caution. They are being trained not to pry apart the metal battery casing for the high-voltage battery, and not to mess with the battery itself. I will leave the rest as an exercise to the student.

Get the latest TTAC e-Newsletter!

21 Comments on “EVs Deadly After They Crashed...”


  • avatar
    rm -rf

    I would also think that the inertia of the batteries during a collision needs to be managed. If that mass is behind the driver, how will it behave during a front end collision?

    • 0 avatar
      Brian P

      Crash testing already addresses this. Most EV’s have the battery beneath the floor structure. It’s not like it’s positioned directly behind the driver’s head with nothing to stop it.

  • avatar
    golden2husky

    Like any new technology, there will be a learning curve involved.  Think about it this way.  Say cars were never gas powered and since day one, they were electric, powered by a battery made of an lithium-unobtainium mix.  Fast forward 100 years and “peak unobtanium” has made production of these batteries impossible.  A startup builds a new means of propulsion by burning volatile, highly explosive, toxic liquid in an onboard internal combustion engine.  And they show a prototype of a car with 22 gallons of it under the rear seat.  What would the first responders say then?  “Them new cars are rolling bombs…we can’t help anybody stuck in on of those?”

    Has there been any data showing problems with hybrids and crashes?  Most cars today have cutout switches on the fuel pump to shut it off in case of an impact and a rollover switch that kills the pump if the car rolls onto it’s roof.  I find it hard to believe that an electrical equivalent would not already be in use.

    • 0 avatar
      mcs

      The nmh batteries in the Prius are not the same as the lithiums in the newer cars. A lithium battery on fire is like a roman candle on steroids. Plenty of videos on you tube. They even require special fire extinguishers – lith-x and Copper Powder Navy125S based.
      http://www.monroeextinguisher.com/catalog.asp?prodid=504348

    • 0 avatar
      Scoutdude

      Not that many cars have inertia switches to shut the fuel pump off. Fords do since the early 80’s and that did cross over to some of the other brands they owned over the years. Other than that VW has started doing it but I think that is tied into the computer system. So rather than a separate sw operated by inertia the engine module turns off the fuel pump relay when it receives an air bag deployed signal from the air bag module.

    • 0 avatar
      RangerM

      Not to worry.  In today’s world, we have our friendly, neighborhood trial lawyer to help sort it out.

  • avatar
    Michal

    This is an easy one.  Remember when the Prius became popular, and the same question arose?  Opponents of hybrid vehicles proposed scenarios where first responders would keep their distance and gaze at someone dying within a vehicle, lest they touch it and be electrocuted.  Anyone who has seen a car wreck knows the A/B pillars are cut and roof peeled to free the victims inside.  Do hybrid and EV vehicles route their power cables through the pillars or roof?  Do petrol vehicles route their fuel lines there too?  Thought not.
    An easy solution for electrocution risk comes from existing vehicle technologies: if the battery is compromised or the battery pack to engine communication lines are severed, the pack is deactivated.  Use a solenoid or electronic methods, both at the battery end and engine.

  • avatar
    don1967

    I like to bash EVs as much as the next guy, but with newer crash detection systems automatically cutting off battery power at the source isn’t this a moot point?

  • avatar
    Robert Schwartz

    I am still wating for a fully charged 24 KWh Li-Ion battery to torch. Should be quite a show.

    • 0 avatar
      joeaverage

      I believe current lithium batteries have a layer of plastic in them that is heat sensitive. If the batteries overheat for some reason the layer prohibits electrons from passing through the layer and the batteries become inert.

      I believe this all came to be after the laptop fires of a few years ago.

  • avatar
    shaker

    I think that the concern would be that on a mid-winter rainy day in the Northeast, the combination of water and leftover road salt could make the area around a wrecked EV a potential “hot zone” if any HV line is exposed, and that fear is justified if the manufacturers haven’t taken that scenario into account. At the very least, a multi-point fuse in the battery pack (for redundancy), would open upon impact, leaving any exposed high voltage cables without power.

  • avatar
    EChid

    I’m really struggling to find a purpose to this article. Yes, in some circumstances, this could be dangerous. But systems would have to fail in unexpected ways for this to be the case. How is a gas powered car any different? Because we can smell it?

  • avatar
    Bill Wade

    Drug dealers. Police officers will search an EV with great caution. They are being trained not to pry apart the metal battery casing for the high-voltage battery, and not to mess with the battery itself. I will leave the rest as an exercise to the student.
    ——————————————————————————-
    The first lithium battery pack blowing up in a drive by shooting ought to fix the drug dealer problem.

    • 0 avatar

      Actually, the biggest problem would be that drug dealer cars would need more than 100 miles of range! And of course if you put drugs in the battery compartment, range would get even worse.
      I wonder how the Volt would run on ICE only, though.  If it would work, then you could use the whole battery compartment, at least in theory.
      D
       

  • avatar

    do they really use 400 volt batteries? that seems crazy to me. isn’t the voltage just stepped up to 400 volts before the motor. big difference in terms of safety between the two scenerios.

    • 0 avatar
      Brian P

      No, the voltage is up there, 200+ volts, the exact number varies.
       
      Higher voltage means lower current in the wiring which means lighter wiring can be used. For example, if you were to try to run a 12 kW (about 16 HP) motor with 12 volts, it would require 1,000 amps!
       
      Don’t forget, you have more than 200 volts in your house, too. And in most industrial applications. And the overhead or underground wires bringing power to your house are at much higher voltage than this and with a lot more power behind them, too.
       
      Much fuss about nothing, in my opinion. Don’t cut the orange cables – which are routed up the middle of the car underneath, same area where most gasoline vehicles route the fuel lines, which you shouldn’t be cutting, either. The cars are specifically designed so that the need for emergency responders to deal with either fuel or high-power electrical is minimized. The battery pack has local circuit protection in case there is a short circuit. And if all else fails and there IS a fire … gasoline is pretty darn hazardous when it catches fire, too.

  • avatar
    probert

    Yeah – and toilets inside a house are unsanitary. And them kids and those crazy headphones jeez.
     
    B.S. : don’t be scared little bunny – come to daddy.

  • avatar
    Zas

    AP Columbia. 9AM GMT. Columbian drug lords just placed an order for 1,000 Toyota Prius Hybrid vehicles. A source who wishes to remain anonymous… er, now dead, said that the idea that they could carefully pry apart the batteries to pack illegal drugs in them was a brilliant idea of Americans who have told their law enforcement officials NOT to inspect EV vehicles in fear of being electrocuted. Another anonymous…er, dead too, source told AP that they will be using the Toyota Prius as drug mules exclusively, with old people driving them, so as to not draw attention to the vehicles going in and out of Mexico, packed with cocaine, heroin and marijuana.
     
    When asked, one of the drug lords said this:

    The Americans are dumb so we plan on buying the first 5,000 Chevy Volts to be used as our preferred method of mule transport, that way the idiot law enforcement people won’t dare tear apart a UAW made car in fear or reprisals from the Unions in America.

    A GM spokesperson could not be reached for comment, but a local Chevy dealer said this:

    We sell to all qualified buyers, even if they bring in cash that’s a little dusty with white powder. As long as it’s cold-hard American dollars, we will sell, sell, sell!

    (ok, the above is a spoof, so don’t get your panties all in a bunch!)

  • avatar
    HoldenSSVSE

    There was much hand wringing about this with early hybrids – it hasn’t panned out to be a real problem.

    As a former EMT the first rule is – don’t become a victim yourself, assess the situation and proceed when it is known to be safe.


Back to TopLeave a Reply

You must be logged in to post a comment.

Subscribe without commenting

Recent Comments

New Car Research

Get a Free Dealer Quote

Staff

  • Contributing Writers

  • Jack Baruth, United States
  • Brendan McAleer, Canada
  • Marcelo De Vasconcellos, Brazil
  • Vojta Dobes, Czech Republic
  • Matthias Gasnier, Australia
  • W. Christian 'Mental' Ward, Abu Dhabi
  • Mark Stevenson, Canada
  • Cameron Aubernon, United States
  • J Emerson, United States