Here Are the Two Problem With EV's

There are two problems with electric vehicles.  Neither are unsolvable in the long-term, but neither are probably going to get solved in the next 5 years.

  1.  Energy Density.  15 gallons of gasoline weighs 90 pounds and takes up 2 cubic feet.  This will carry a 40 mpg car 600 miles.   The Tesla Model S  85kwh battery pack weighs 1200 pounds and will carry the car 265 miles (from this article the cells themselves occupy about 4 cubic feet if packed perfectly but in this video the whole pack looks much larger).  We can see that even with what Musk claims is twice the energy density of other batteries, the Tesla gets  0.22 miles per pound of fuel/battery while the regular car can get 6.7.  That is a difference in energy density of 30x.  Some of this is compensated for by heavy and bulky things the electric car does not need (e.g. coolant system) but it is still a major problem in car design.
  2. Charge Time.  In my mind this is perhaps the single barrier that could, if solved, make electric cars ubiquitous.  People complain about electric car range, but really EV range is not that much shorter than the range of traditional cars on a tank of gas.  The problem is that it is MUCH faster to refill a tank of gas than it is to refill a battery with a full charge.    Traditionally it takes all night to charge an electric car, but 2 minutes at the pump to "charge" a gasoline engine.   The fastest current charging claim is Tesla's, which claims that the supercharger sites they have built on many US interstate routes sites will charge 170 miles of range in 30 minutes, or 5.7 miles per minute.   A traditional car (the same one used in point 1) can add 600 miles of range in 2 minutes, or 300 miles per minute, or 52 times faster than the electric car.  This is the real reason EV range is an issue for folks.

Interestingly, Fisker (which failed in its first foray in to electric cars) claims to have a solid state battery technology that gets at both these issues, particularly #2

“Fisker’s solid-state batteries will feature three-dimensional electrodes with 2.5 times the energy density of lithium-ion batteries. Fisker claims that this technology will enable ranges of more than 500 miles on a single charge and charging times as low as one minute—faster than filling up a gas tank.”

Forget all the other issues.  If they can really deliver on the last part, we will all be driving electric vehicles in 20 years.  However, having seen versions of this same article for literally 30 years about someone or other's promised breakthrough in battery technology that never really lived up to the hype, I will wait and see.


  1. Dan Wendlick:

    my concern is if safety regulations are going to allow for the kind of charging times that the battery companies are claiming. Currently I need to have special clothing or be 3-4 feet away from any high voltage connections being made. If they are going to be running the kinds of current needed to fill these batteries in that kind of a timeframe, then the voltages are going to have to be in the arc-flash warning range. I don't see this at a consumer self-serve level even with permissive-action safety features.

  2. me:

    Interesting point - I am still on the fence about electric vehicles; it's possible that battery tech and electricity generation will advance to a level where a nation wide network of electric vehicles functions well and makes economic sense, but I am not convinced that'll happen yet.

    Food for thought though: *if* that turns out ok, then the progressives will have done wonders for energy independence and technological sea change in the transportation industry, even though they went into this for all the wrong reasons.

  3. The_Big_W:

    I'm sure they'll come up with a way to do this. After all its not really super safe to rapidly pump out high volumes of a very flammable substance either.

  4. C078342:

    How many gallons of gasoline are pumped into cars daily and how many news stories do you see about fires. The answers are 1. many, many, many gallons and 2. I can't remember a news story or television coverage of ANY.

  5. jon49:

    Can't wait until the electrical cars are practical and ubiquitous. Just for not needing oil changes and hardly ever needing to change out the breaks and having a motor that should pretty much last forever would be wonderful!

  6. cc:

    I am waiting for the first batch of electric cars to need new batteries. Maybe with a Volt you just throw the car away at 8 years but not with a Tesla. I have heard up to $20,000 for new batteries. Batteries do not last forever.

  7. sailor116:

    If you could replace batteries rather than recharge them (quite doable by robots) then you could swap out a car's worth of batteries in a few minutes. But that would only work if there was an imposed standard of shape, composition, and access.

  8. DaveK:

    Don't get too excited yet about the Fisker battery pack. It may be a wonderful technological advance, but there are issues.

    Other experts have estimated that the Fisker battery would store something in the neighborhood of 130KWH to achieve the projected vehicle range. The 1-minute charge was estimated to be around 80% of battery capacity, so you are talking about pumping something like 100KWH into the battery within one minute. Yikes, that's 6 Megawatts being pushed into just one battery! What could possibly go wrong?

    Then there is the little detail about batteries, that it's always possible to discharge it much faster (with catastrophic effect, of course) than it can be safely charged. Even with a partial charge, dumping 50 KWH of power within a few seconds is something I would not want to be near.

    I can see the accident reports now: "...and then there was this blinding blue flash."

    Perhaps they can get the safety issues worked out, but it will take a lot of time, and may require some rather expensive equipment. I'm not going to get rid of my gas-guzzler just yet.

  9. Brad Warbiany:

    When a Volt's batteries die, it becomes a conventional gasoline car.

    When a Tesla's batteries die, it becomes a doorstop.

    I don't know why plug-in hybrid isn't more of a thing. It seems to be to be the best of both worlds. Yet it hasn't taken off, while all-electric cars with their inherent range limitations are all the rage.

  10. DaveK:

    Safety in handling flammable liquids is quite routine, and easily accomplished. Safety involving very high voltages and electrical power is quite more complicated. The Tesla batteries are bad enough, but Fiskers? I wouldn't want to be anywhere near one of those when it's being charged at its projected rate. Thinks can go very badly wrong in just the blink of an eye.

  11. aczarnowski:

    And isn't that amazing? Would anybody today take the bet that gas pumps would work if it was a brand new technology? I sure has hell wouldn't given what kind of drivers most of the road is filled with these days.

  12. Ellen McKaskle:

    That is because government pushes politically correct all electric cars--I don't think they are the "rage" except in the minds of government pushing car companies to manufacture them.

  13. J K Brown:

    "will feature three-dimensional electrodes"

    Really, three-dimensional? I for one see great things now that they are escaping their two-dimensional world. Sure it's the marketers who chose those technologically "thrilling" words, but that's all they got?

  14. rst1317:

    That's the thing, 5, 10 20 gallons in a minture or three is NOT a high volume. And the gasoline isn't the issue, it HAS to be combined with enough of a flame to cause the issue. You have to have 2 things combine for the danger to become real. This is why, if you do enough driving on enough backgrounds, can still come across people smoking while filling their tank and yet we don't have montly reports of gas stations exploding.

    The electricity issue is that you don't have to have 2 things. YOu have the one thing and if it arcs at those levels, you're dead.

  15. markm:

    There's another problem revealed in DaveK's numbers: The 1-minute charging station would need a connection to the grid of 6MW per charger. A house will typically have a connection of around 10KW, and draw 1KW on the average. ONE CHARGER will put a load on the grid equivalent to a neighborhood of 600 to 6,000 homes.And that's just for the equivalent of a 1-pump gas station. When they get more than 1% of us into electric cars, there will have to be charging stations with multiple chargers. Each of these will require it's own electrical substation, fed by high-tension power lines similar to those needed to connect a power plant to a small city. New power plants will also be needed - and the same nuts calling for the end of internal-combustion powered cars will picket and sue every time a new plant is proposed...

    Then there is the effect on grid stability. Starting and ending a 1-minute charge is the equivalent of everyone in that neighborhood switching major appliances on and off SIMULTANEOUSLY. The only time the grid gets that kind of load change now is when a section of it is turned on or off, and the power companies have engineers present when they do that.

    For the more believable 30-minute charge times, the effects of sudden load switching are reduced, but the power requirement for the charging station is not. It's still handling the same power, but now it's spread over 30 times as many chargers. (Also think about the space required to replace a gas station with 10 pumps with a charging station accommodating 100 cars at a time - and 100 customers wandering around while waiting on a charge.)

  16. Brad Warbiany:

    In the movies, they show someone dropping a lit cigarette on a trail of gasoline, and "woosh!" up in flames.

    If you've ever tried it, you know that won't ignite gasoline. It will put out the cigarette.

    Back in college, my friends and I tried it several times, when trying to light a bonfire. Pour a little gas on the wood pile, make a little trail to a safe[ish] distance, and drop a cigarette on it. Nothing. Nothing at all.

    The only way to get gas to ignite is a spark or an actual open flame.

    Not that smoking at a gas station is a *good* idea, but for as dangerous and explosive as gasoline can be, it's actually slightly harder to ignite than most people think (and than the movies suggest).

  17. jon49:

    @markm, More than likely the charging station would fill up a storage capacitor of some sort. So, it would trickle the electricity, it wouldn't get it all at once, that would be dumb. It would be similar to CNG (compressed natural gas) filling stations where the gas is trickled to the station and there is a compressor that slowly builds up the gas. So, if the station is really busy it takes longer to fill your CNG tank. Likewise with electricity. If electric cars became super popular I would expect some similar solution at first and eventually maybe the power grid would be upgraded to handle more power. It will take time and a lot of money. But if ev's are the future then people will get it done.

    If you think about it. That is pretty much how gasoline works too. You fill up some tankers and then send them on their way and fill up each station. Except you can still fill up at the same rate unless they run out of gas. So, there has to be local storage of the energy.

  18. markm:

    "Some kind of storage capacitor" that doesn't exist.

  19. jon49:

    Exactly, a lot of hurdles to over come. But whoever thought they would be coming out with EVs that can go hundreds of miles on a single charge? It is quite remarkable. Who knows what new tech there will be in the next 20 years. Hopefully some pretty cool stuff, I'm sure!