I'll always remember my high school chemistry class where the teacher dropped a chunk of Potassium into water and it burned, then dropped a chunk of Sodium into water and it REALLY burned, then dropped a chunk of Lithium into water and it practically exploded. Always wondered what they would do if one of these electric cars caught fire, now I know ... run away!

The Li metal used in the Volt batteries is a bound form of the metal and thus not flammable. The reason you get fires in these batteries is that the membrane perforates and liberates a lot of energy at the site of the perforation, vaporizing/igniting the electrolyte.

Because the metal is bound, it does not represent the same difficulty to extinguish as lithium metal fires, which *do* happen with lithium *primary* non-rechargeable cells.

Therefore, Volt cars don't represent any special fire risk with regard to the battery material itself, but they do present a risk due to the construction of batteries. Effectively, an electric car has the equivalent of a couple gallons of gasoline that by necessity are contained by the equivalent of a fragile ziploc baggie. Nick the bag even a little bit and WHUMPF.

IMHO, in the short term the way forward is gas/diesel microturbines and supercapacitors. Nothing will approach the energy density of hydrocarbons for some time.

Right but the point is that the ENTIRE energy in the pack will be liberated in this fashion, and the electrolyte is very flammable. As long as you have a heat source (as long as there is energy in the pack) you have a fire that is almost impossible to put out.

Primary lithium batteries are even worse for all the obvious reasons but the point here is that due to the extremely high short-circuit current capacity of these cells if there is a membrane violation on a charged pack you're virtually certain to get a fire.

Grf: In the intermediate term (hundreds of years) the way forward is Thorium from coal and using the coal itself as a feedstock for conversion to liquid petroleum fuel.

Battery fires are no joke.

http://en.wikipedia.org/wiki/USS_Bonefis....

Quote:

On 24 April 1988, Bonefish was exercising with the guided missile frigate Carr 160 mi (260 km) off the coast of Florida. While the sub was submerged, seawater began leaking onto cables and electrical buses in a battery supply cableway. Electrical arcing between cables caused an explosion which flashed into a fire within minutes, with temperatures in the battery spaces reaching 1,200° Fahrenheit. The heat was so intense that it melted crew members' shoe soles in the spaces above. Bonefish was surfaced and its crew ordered to abandon ship. Eighty-nine crew members were rescued by whaleboat and helicopter crews from Carr and the aircraft carrier John F. Kennedy. One Search and Rescue Swimmer from HS-7, Anti-Submarine Warfare Operator Third Class (AW3) Larry Grossman spent over three hours in the ocean and was credited with saving 19 lives. He later received the Navy and Marine Corps Medal for Heroism. With the fire extinguished, Bonefish was subsequently towed into Charleston, South Carolina by salvage and rescue ship Hoist. Three sailors—Lieutenant Ray Everts, Petty Officer 1st Class Bob Bordelon, and Petty Officer 3rd Class Marshal T. Lindgren—were killed.

The damage to Bonefish was deemed too extensive to warrant repair, and a decision was made to decommission her and dispose of her via scrapping.

"As long as you have a heat source (as long as there is energy in the pack) you have a fire that is almost impossible to put out."

Well, kinda. Once the electrolyte ignites, it's just a standard liquid fuel fire that fire departments know how to handle like a gasoline fire. Lithium packs on fire tend to discharge all their energy relatively quickly as the fire heat further degrades the membrane which sources more current in a positive feedback loop. All the energy is gone in a few seconds. The point is that you *don't* have a lithium metal fire which reacts to water with increased ferocity as the lithium is not in a reactive form.

Totally agree on coal, I was speaking of the technology in the cars themselves. Battery-powered electric cars are a dead end IMHO.

Last year a home in my neighborhood caught fire. It was determined that an electric car charging in the garage was the cause. Not real sure I'd want to be in one of these new-fangled vehicles in an accident.

I fly model helicopters that use various sizes of lithium-ion batteries. We are constantly barraged with reminders to never charge the batteries while not present, due to the risk of a battery fire while charging. We are also told to put both the battery and charger in some type of containment device while charging, so if something untoward does happen its contained.

Its never happened to me, but I've read of it happening to others. And there are some videos on YouTube where folks intentionally over-charge these type of battery to show what can happen.

Abnormal, the reason that Bonefish was so bad was that IIRC the batteries weren't sealed so they liberate hydrogen during discharge which then ignites. Combine that with batteries capable of sourcing tens of thousands of amps into an arc flash, and fun ensues.

Arc flash scares the **** out of me. Google for videos. Brrr...

Thorium... thorium... thorium... thorium... thorium... thorium... thorium... thorium... thorium... thorium... thorium... thorium... thorium... thorium... thorium... thorium... thorium... thorium... thorium... thorium... thorium... thorium... thorium... thorium... thorium... thorium... thorium... thorium...

Oh, before I forget, thorium.

Grf, no, it's not quite the same thing at all.

Fires are a triangle - heat, oxygen, fuel. Water attempts to interrupt access to the oxygen AND deny the fire heat.

The problem with a cased battery fire (like this) is that the heat source is INTERNAL; it's not just the burning electrolyte that evolves heat but also the shorted batteries that provide substantial heat support and the plate/case construction prevents the water from getting in to the source and absorbing the heat (through flashing to steam)

The same bug-a-boo exists for most electrically-fed fires; they're damn hard to put out until you can cut off the energy source because there is a heat source beyond the actual combustion available to feed the fire. In this case you CAN'T interrupt the energy source which means all you can really do is suppress (not extinguish) the fire until the entirety of the available charge in the pack has been consumed as heat, at which point you can actually put it out.

Same thing happens with the little (by comparison) rechargeable batteries used in laptops and RC airplanes. If one of those goes up the usual idea of hitting it with a dry chem extinguisher will not actually put it out until the charge is consumed, and much to the surprise of the person trying it will simply evolve more vapor-phase electrolyte over the top of the deposited dry chemical from your extinguisher shot and reignite! I've intentionally caused one of these pack fires and they're damn impressive and very hard to extinguish.

It is, however, of a different magnitude than a primary lithium fire - that's true.

One of my hobbies is flying r/c aircraft. Electric has gone from fringe to mainstream. The hazard of lithium batteries is well known in my circles.

Funny how I was reading a book written in 1894 a few weeks ago, talking about the new invention of electric cars... they could run at 30 miles an hour for about 35-40 miles.

That was in 1894... And in the book, there was an inventor of electric cars that destroyed the cars running on gas... and the points he was bringing were quite funny... like the smell of oil, the impossibility of storing enough gas for everyone in a single place, the fire and explosion risks from gas storing and the funniest of it, the complexity of gas engines, which meant that only an ``expert`` could fix the car, compared to the electric car, that could be fixed by any 13 years old with a 5 minute course... And you know what's funny? GE was building electric batteries for those cars...

I have not watched ``Who killed the electric car`` but I bet it's good.

It's horse****.

Look, gasoline (petroleum generally) is just a battery. It happens to be one with extraordinary energy density, but it is a chemical energy storage device. That's a battery.

Electric cars (not electric-ASSISTED cars, pure electric cars) have several problems:

1. Energy density. The battery has the oxygen in the case. The gas car uses oxygen from the air. Oxygen has mass and size. Guess what this means? Yep; there's an energy density problem for electric batteries. There are people trying to fix this by getting the oxygen from the air, but even if they do at some point in the future we have....

2. Charge acceptance. Simply put, you can replace the gasoline in your tank in a couple of minutes. The reality of internal resistance along with other factors means you CAN'T put the energy in a battery back in 5 minutes after driving for an hour depleting it. We have made a lot of progress in this area but we're a hell of a long way from being able to charge at rates of 20x that at which we can safely withdraw the energy from the cell. In fact, the two tend to be rather symmetrical (which makes perfect sense when you think about it) but you'll never put up with being able to drive for an hour and then needing to charge for an hour!

And finally, we have as another immutable reality....

3. End-to-end loss. More conversions = more losses. Thermodynamics says you can't cheat this -- it's physical fact. Charge acceptance has loss and so does generating the electricity you want to put in the battery. That you don't SEE the pollution doesn't mean it doesn't happen -- doing it 100 miles away in a coal-fired power plant is no different than doing it in the engine in terms of environmental impact on the gross scale. While it is true that large-scale generation is materially more efficient than burning carbon fuel in a car, end-to-end it's not THAT much different when you add all the losses up in terms of the percentage of the original energy that goes into moving you down the road.

So a battery that may not have been rendered safe or removed after a _crash test_ catches fire _3 weeks later_?

OMGNOZRUNRUNRUN!!!!

Speaks more to NHTSA incompetence or ignorance than any design flaws IMO..

The real problem is not the energy density, but the notion that it takes 2000-6000 pounds of machine to transport a 100 to 200 pound person (or a few of those). Schweeb demonstrates the ability to move a person around a city, at the same or better speed than today's cars, using the mechanical energy a human can produce (100-200 watts or .14-.3 horsepower). Evacuated tube technology (et3.com) can move people between cities 10 times faster than today's planes at a similar energy cost.

If one considers all the metrics of a transportation system: energy consumption per mass moved per distance unit, safety, ancillary resource consumption, land use, ... both our current automotive and mass transit systems perform very poorly. In Canada, 50% or our energy consumption is related to our transportation system. We could reduce this by a factor of 20+ if we just decided to use more appropriate transportation mechanism. These would simultaneously reduce the costs in all other areas such as injuries to people moving and third parties (see 9/11)).

We do not need better energy generation or storage technology. We need to have a transportation system whose goal is to move people and goods as efficiently as possible. We know how to do that (with PRT and ETT). Using 10-20 times the mass of the payload is irrational.

The same issues applies across every aspect of our economy. The next largest energy consumers are HVAC systems. The Drake's Landing project demonstrates the potential in this area.

We do not need thorium or any other generation technology. We need to understand the end user need, and find the most effective means to deliver that. In my analysis of the energy consumption in North America it seems like we could have an equivalent delivery of primary needs such as food, water, shelter and entertainment at 1 per cent of today's energy expenditure.

I would agree that there is no way electric cars are gonna replace anything until they can be recharged in approximately the same time as it takes to fill a tank with gas.

This and the driving range HAS to get bigger. Even if they solve the above charge acceptance issue, no one wants to stop every 45 minutes to "recharge" the tank for 5-10 minutes while driving places.

There are plenty of stretches of highway across the U.S that have no gas stations for 50+ miles. To really work they need to solve the charge acceptance issue AND make a car that can run at least 150-200 miles before needing a recharge.

Incidentally, electric powertrains are inherently more efficient than those that are gasoline- or diesel-powered. Me, I'd like to see fuel cells that could accept gasoline (perhaps SOFCs?) as an electric 'range extender', with a smaller battery or set of capacitors to do regenerative braking and allow for efficient city travel.

Additionally, this sort of thing could help with H2 storage at reduced pressures:
http://www.sciencedaily.com/releases/200....

That'd allow for H2 vehicles, which would initially get H2 from reformulated hydrocarbons, until it could be pipelined in from LFTRs or other nuclear reactors that crack water..

(ps: http://www.rsc.org/chemistryworld/News/2.... graphene <-> graphane also looks particularly promising for H2 storage)

Gpromhouse -

Just like the electric cars, concepts such as Schweeb, PRT, ETT, etc. are great when looked at as individual, localized transport elements, but I have not heard of any thorough end-to-end analysis (which includes ALL factors such as right-of-way procurement, infrastructure rqmts, etc.) that demonstrates feasibility as primary transport mechanisms on a national scale.

If you have links to studies which do so, please post them.

Who cares. The fire is for the children. And is part of the Win The Future Green Jobs/Energy policy of the 21st century. And Environmental Watermelons love it !

Stop tha hatin'!!!

Otis: Well, they are sorta.

Let's assume 80% conversion efficiency during charge, 80% in discharge (chemical to electrical) and 90% (achievable but somewhat difficult) through the controller and motor. By the way those battery numbers are good for the bulk charge/discharge portion but ridiculously optimistic once the battery gets reasonably close to "full" (charge losses go up as the percentage of charge rises.)

These "stack", so from the inlet into the car to the wheels you have 57.6% efficiency.

The best thermal efficiency on a combined-cycle plant we've got at present is in the 60% range. So end-to-end (fuel to wheel) it's 34.5% if the energy source is combined-cycle. (If it's not then the numbers are MUCH worse!) Note that we're ignoring parasitic losses (e.g. lighting, air conditioning or heating, PTOs for various purposes, etc) and also ignoring the final drive losses (since they'll exist for both gas and electric, although 'wheel motors' could eliminate another 3% or so of the total loss budget, at least in theory.) Since both of these losses exist for both electric and ICE ignoring them is the correct comparison.

An internal-combustion engine is ~25-30% efficient in gross conversion at present (from fuel to mechanical energy at the output shaft) at "best output." Current engines tend to be in the low 20s in the real world mostly because they are usually run at ridiculously low percentages of power output and pumping losses for gas engines are considerable with the throttle plate mostly-closed. The reason for this in modern vehicles is that we all want to be able to "vroom" so we have much larger engines than are actually necessary and this drives down the curve where it operates most of the time. This is true to a lesser extent with diesels (no pumping losses but nonetheless BFSC efficiency is best in the ~75% power output area.)

So there's a sizeable difference, yes, but it's not the sort of ridiculously large difference you might expect. And you can't get materially better in the gas engine case; we've gone pretty much as far as we're able.

Note that we could get MUCH better gross efficiency out of a gas turbine, IF it runs at or near full output all the time. The problem is that when used in a car nearly all of the time it doesn't.

Aerodynamic improvements, acceptance of slower acceleration (less "reserve power" capacity) and similar do leave some room for improvement, but the big gains have been made.

Evacuated-tube and similar ideas cut the energy requirement to move "things" a LOT, especially if you recover the energy used for acceleration on the deceleration side, but the capital cost of construction and how close it gets you on both ends to the desired place creates some problems, not to mention the parasitic losses in maintaining the vacuum and similar concerns.......

Gprom,

I want to be able to stop off at the liquor store on the way home.

Genesis wrote..

Note that we could get MUCH better gross efficiency out of a gas turbine, IF it runs at or near full output all the time. The problem is that when used in a car nearly all of the time it doesn't.

You could run it at full output all the time if you put it in a hybrid vehicle. Use capacitors rather than batteries for intermediate storage for even better efficiency.

Quote:

Note that we could get MUCH better gross efficiency out of a gas turbine, IF it runs at or near full output all the time. The problem is that when used in a car nearly all of the time it doesn't.

With an electric drivetrain using a gas turbine as a genset, you could have the turbine run at full output, with excess power at lower speeds to charge a smaller battery. Turbines are also lighter and mechanically simpler (fewer moving parts, though engineering the tolerances is tougher).

Quote:

Evacuated-tube and similar ideas cut the energy requirement to move "things" a LOT, especially if you recover the energy used for acceleration on the deceleration side, but the capital cost of construction and how close it gets you on both ends to the desired place creates some problems, not to mention the parasitic losses in maintaining the vacuum and similar concerns.......

At a purely geek-out level, this is how I'd expect to see _true_ high-speed trains in the future: maglevs running thru evacuated tubes at ridiculous speeds, elevated along existing rights-of-way (either train or highway). 1000MPH, you could have service from, say, Houston to Dallas in 20-30 mins or so, downtown-to-downtown..

For people who care to know, there's a new movie out about this stuff: http://www.revengeoftheelectriccar.com/i....

I assume the movie is unintentionally hilarious, with a cast that includes the singer from the Red Hot Chili Peppers & San Francisco mayor Gavin Newsome.

I prefer to do anything I can to help global warming along.