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First Responders Unprepared for Electric Vehicle Fires: Report

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Re: First Responders Unprepared for Electric Vehicle Fires: Report

#41

Post by imglorp »

Reason077 wrote: post #36
imglorp wrote: post #29

Earlier quoted context omitted.

Unscheduled airbag deployment is a terrifying concept if you're trying to lean in to access a person. Why do military aircraft have RESCUE --> levers that disarm all the pyros but we can't make that a thing on cars? It wouldn't have to be a big red sign but it could be a standard.

> "Why do military aircraft have RESCUE --> levers that disarm all the pyros but we can't make that a thing on cars?" Not sure if it's standard on all EVs, but cutting the first responder loop on a Tesla will disarm the airbags & SRS, in addition to disconnecting the high voltage system. Source: Tesla first responder guide: https://www.nfpa.org/-/media/Files/Training/AFV/Emergency-Re...

> first responder guide

This is exactly what I'm complaining about. Every car is different. Volunteers have so many trainings to take, it's unreasonable to ask them to take a whole training for EVERY MODEL CAR on the road. There should be a simple, standard, HV and pyro cutoff control, standard on ALL cars, that can be actuated without a hydraulic shear. Put it in the wheel well or behind a gascap-like door.

Imagine you are a civilian or first responder and want to help people out of a car and you don't have a hydraulic shear or hundreds of hours of model-specific training? This is an everyday usecase.

Re: First Responders Unprepared for Electric Vehicle Fires: Report

#42

Post by _ph_ »

LatteLazy wrote: post #20
exabrial wrote: post #19

One of my firefighter friends says they're a little fearful of using the jaws of life on electric vehicles since cutting through a high-voltage electrical cable would be disastrous. Luckily there are so few models right now they can memorize no-go places, but obviously this can't be counted on forever.

Edit: Cell voltage in a tesla is only 4.1V max. But there are systems with up to 375 total so I guess it's a valid question, especially as company's (not tesla AFAIK?) start putting cells into the body to squeeze as many as possible in... Original question: Isn't it all low voltage?

Tesla battery packs connect like 96 cells in a row to achieve the desired voltage and then many rows wired in parallel for the current. As P=U*I, you have to use 400V to keep the motor current somwhat reasonable. Still, for the performance Model S, the current at which the pyrotechnical breakers cut in ist 1500A, which is beyond scary :).

Re: First Responders Unprepared for Electric Vehicle Fires: Report

#43

Post by reportingsjr »

gondola wrote: post #23
londons_explore wrote: post #5

The issue of EV batteries reigniting after a crash seems very solvable... For example, every battery cell could have a built in discharge circuit. Whenever the cell no longer received a signal from the cars computer indicating "the car is healthy" it goes into failsafe mode. Failsafe mode consists of every cell discharging to zero volts through a PTC resistor to keep a constant temperature of 150 degrees C. That will…

Li batteries ignite equally when charged or discharged. It's got nothing to do with charge state. The ignition is caused by Li contact with air or water, when the battery barrier is breached.

Primary fire cause from lithium batteries is not the lithium, it is the organic solvents contained in the battery electrolytes.

Re: First Responders Unprepared for Electric Vehicle Fires: Report

#44

Post by gregd »

dreamcompiler wrote: post #18

Firefighter/EMT here. Our department has trained on hybrids (don't cut the big orange cable!)[0] but not electric per se. Doesn't matter. Unless there's someone in the car, we're going to stand back, let it burn, and keep it from spreading. Cars contain bigger hazards than batteries: Airbags are basically bombs, and gas lifters (the things that make the hatchback open smoothly) can become missles in a fire. And that…

Former firefighter here also. We also used to have to worry about the compressed gas cylinders on bumpers.

Re: First Responders Unprepared for Electric Vehicle Fires: Report

#45

Post by dzhiurgis »

imglorp wrote: post #29
dreamcompiler wrote: post #18

Firefighter/EMT here. Our department has trained on hybrids (don't cut the big orange cable!)[0] but not electric per se. Doesn't matter. Unless there's someone in the car, we're going to stand back, let it burn, and keep it from spreading. Cars contain bigger hazards than batteries: Airbags are basically bombs, and gas lifters (the things that make the hatchback open smoothly) can become missles in a fire. And that…

Unscheduled airbag deployment is a terrifying concept if you're trying to lean in to access a person. Why do military aircraft have RESCUE --> levers that disarm all the pyros but we can't make that a thing on cars? It wouldn't have to be a big red sign but it could be a standard.

I find it hard to believe electronically controlled airbags would just pop out of nowhere. Don't they need a specific message to fire?

Re: First Responders Unprepared for Electric Vehicle Fires: Report

#46

Post by gregd »

imglorp wrote: post #41
Reason077 wrote: post #36

Earlier quoted context omitted.

> "Why do military aircraft have RESCUE --> levers that disarm all the pyros but we can't make that a thing on cars?" Not sure if it's standard on all EVs, but cutting the first responder loop on a Tesla will disarm the airbags & SRS, in addition to disconnecting the high voltage system. Source: Tesla first responder guide: https://www.nfpa.org/-/media/Files/Training/AFV/Emergency-Re...

> first responder guide This is exactly what I'm complaining about. Every car is different. Volunteers have so many trainings to take, it's unreasonable to ask them to take a whole training for EVERY MODEL CAR on the road. There should be a simple, standard, HV and pyro cutoff control, standard on ALL cars, that can be actuated without a hydraulic shear. Put it in the wheel well or behind a gascap-like door. Imagine…

Training on fire suppression and extrication techniques for cars doesn't take THAT much training. Most techniques would be standard across the board, with a few exceptions for electric vehicles.

Additionally, never underestimate the hours of training that most firefighters go through anyway and get this, they live for that stuff.

Re: First Responders Unprepared for Electric Vehicle Fires: Report

#47

Post by userbinator »

dzhiurgis wrote: post #45
imglorp wrote: post #29

Earlier quoted context omitted.

Unscheduled airbag deployment is a terrifying concept if you're trying to lean in to access a person. Why do military aircraft have RESCUE --> levers that disarm all the pyros but we can't make that a thing on cars? It wouldn't have to be a big red sign but it could be a standard.

I find it hard to believe electronically controlled airbags would just pop out of nowhere. Don't they need a specific message to fire?

They contain explosives, which often don't need more than a bit of heat to go off.

Re: First Responders Unprepared for Electric Vehicle Fires: Report

#48

Post by dzhiurgis »

LeifCarrotson wrote: post #11
londons_explore wrote: post #7

Earlier quoted context omitted.

A big firehouse is 184 Megawatts of cooling (assuming it is all vaporised). That will empty your battery in literally 2 seconds if you can direct it well enough... No breaking physics laws necessary.

I did a tour of an 80 MW coal power plant during my electrical engineering coursework. You're not going to fit an 184 MW heat exchanger in the garage the car gets parked in, much less the battery pack under the floor. Also, as the article suggests, carbon monoxide is bad, and obviously you need oxygen to breathe, but firefighters have equipment that can help with that. However, when you've directed all the energy in…

It's almost like we should tax unsafer lithium tech used in sports and truck/commercial EV's more than LiFePo2, NMC and other safer but less dense chems.

Re: First Responders Unprepared for Electric Vehicle Fires: Report

#49

Post by throwaway0a5e »

FireBeyond wrote: post #21
dreamcompiler wrote: post #18

Firefighter/EMT here. Our department has trained on hybrids (don't cut the big orange cable!)[0] but not electric per se. Doesn't matter. Unless there's someone in the car, we're going to stand back, let it burn, and keep it from spreading. Cars contain bigger hazards than batteries: Airbags are basically bombs, and gas lifters (the things that make the hatchback open smoothly) can become missles in a fire. And that…

> Our department has trained on hybrids (don't cut the big orange cable!) Keep training up to date. Hybrid HV wiring has a conductive sheath around the actual wiring, separated by non conductive layers. The purpose of this is that when your tool cuts such wiring, it shorts the sheath first and trips a breaker, so that you should be able to cut. There's a group near here (WA state) that does demos including "throwing"…

>Pretty low risk. Broken headlight, and behind it is a high voltage arc? That's a very real electrocution hazard.

There's not enough amps available there to do anything serious.

Re: First Responders Unprepared for Electric Vehicle Fires: Report

#50

Post by imglorp »

dzhiurgis wrote: post #45
imglorp wrote: post #29

Earlier quoted context omitted.

Unscheduled airbag deployment is a terrifying concept if you're trying to lean in to access a person. Why do military aircraft have RESCUE --> levers that disarm all the pyros but we can't make that a thing on cars? It wouldn't have to be a big red sign but it could be a standard.

I find it hard to believe electronically controlled airbags would just pop out of nowhere. Don't they need a specific message to fire?

There are several preconditions. It's not a computer message; think 1970s tech. There's a accelerometer to say you need a head-on crash and a seat mass sensor to say there's a large enough human in the seat. There are cases where the passenger bag did not deploy, for example a stuck-closed accelerometer, and then a responder knelt on that seat getting to the driver, satisfying the last condition, and causing a deployment with obvious injury.
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