Take No Prisoners

Eight Mental Mistakes Preventing us from Building Good Electric Vehicles

It’s hard for car companies to build electric vehicles because they’re wrapped up in car thinking instead of electric vehicle thinking. Cars, as in four-wheel vehicles that carry two to six passengers using power generated from internal combustion engines, are nothing like electric vehicles… at least not if we want the EVs to be any good. Let’s examine some of the differences.

1. Single engine vs. wheel motors

Cars generally have one engine, which converts potential energy (stored in gasoline, diesel, ethanol, etc.) into kinetic energy (rotation). This rotation is then carried via a rotating drive shaft to the wheels. This doesn’t make any sense for an electric vehicle. Electric motors are small and can be placed adjacent to (or inside) the wheel they turn. If one breaks, the other three can still push the car. This also simplifies automatic traction control, and allows a more balanced vehicle weight. The heavy drive shaft can be replaced by much lighter electrical cables connecting the motors to the batteries.

2. One gas tank vs. many batteries

Since gasoline is a liquid, and has to be pumped into a vehicle, it made sense to store all the car’s gas in a single tank. Batteries are not liquid. An electric vehicle does not need a single gigantic battery in the middle. It can have a plethora of small batteries, placed wherever is convenient. The mechanical engineer is free to rearrange batteries of varying sizes to manipulate the car’s center of gravity, handling and performance in crash tests.

3. Breaks vs. generators

Cars have brakes – pads that create friction within the wheel assembly to slow the car. This kind of brake system is unnecessary in an electric car with wheel motors – when you want to slow down, you just reverse the motor and it becomes a generator. This not only rapidly slows the vehicle but also charges the batteries. Want a list of other things electric vehicles don’t need? How about mufflers, exhaust pipes, pistons, carburetors, spark plugs, gas tanks, fuel lines, brake fluid, starting motors, crankshafts, fuel injection systems, turbochargers, transmissions, clutches, ignition systems, liquid cooling systems, drive shafts, stick shifts, tachometers, and differentials. Electric vehicles are just simpler.

4. Single vs. multiple energy sources

Cars burn gas (or diesel, or ethanol, or whatever). The point is that cars get energy from exactly one source – whatever’s in the tank. EVs, in contrast can exploit many energy sources, from plugging in to a traditional wall outlet, to regenerative braking (mentioned above), to photovoltaic paint, to pedal power, to wind, to heat. So when you hear these assholes saying “biodiesel can’t solve the energy crisis because there’s not enough of it” (substitute hydro, solar, wind, tidal, geothermal etc. for bidiesel), offer them a steaming cup of shut the fuck up. It’s not about one magic bullet, it’s about the combined electrical output of everything we can find. This applies to individual cars as well as the electric grid as a whole.

5. Heavy vs. light

Cars, vans, SUVs, and trucks are heavy. Everything about them is heavy, from the engine to the seats, steering columns and chassis. The first rule of efficient vehicles is ‘Heavy is bad!’ What the car companies need to do is hire bicycle designers. Those guys understand how to make things light and strong. Consider the extent of this inefficiency: A typical 1/2 ton truck (say a 2002 Ford F150) weighs about 4000 lbs and can carry about 2000 lbs. A Surly Big Dummy longtail bicycle, in contrast, weighs about 40 lbs, and can carry 400.

6. Traveling vs. commuting

“But what if I want to go on a road trip?” people always ask when someone points out that electric vehicles have a particular range. How many goddamn road trips do you go on? First, if 99% of your travel is within a city, or from a suburb to city and back, that’s what EVs are for. If you’re using your car to travel hundreds of kilometers at once on a regular basis, you need to rethink your lifestyle. Second, both EVs and cars have a particular range. The difference is pumping gas is fast and recharging batteries is slow. This isn’t an EV problem, it’s a battery technology problem – particularly a problem with chemical batteries. It requires us to rethink energy storage. One alternative with some potential is the high-speed flywheel. On a related note, vehicle designers shouldn’t assume that power will be stored in chemical batteries (or fuel cells, or whatever). We should review as many energy storage alternatives as possible, and pick the best combination.

7. Gas stations vs. ubiquitous charging

When the tank is low, car drivers stop at gas stations to refill. EVs, in contrast, are recharged at home – at least, that’s the current thinking. We need to start thinking of EVs as charging all the time, as if they were little rolling power-plants. We also need to think of plugging EVs into the grid whenever we park, be it at home, in the parking garage at work, in the parking lot at the mall, etc. Having millions of EV-sized batteries connected to the grid allows for the kind sophisticated power management described by Thomas L. Friedman. Short version: the grid charges batteries when demand is otherwise low (at night) and drains them (just a little bit) to even out demand peaks. You can, of course, override the centralized power management and set the EV to charge if you have far to go. In summary, we need to start thinking about ubiquitous connection infrastructure, rather than intermittent fueling stations.

8. Parallel vs serial hybrids

The Toyota Prius and virtually every other hybrid car you see on the road today is a parallel hybrid. An internal combustion engine and an electric motor simultaneously generate torque, which is combined in the drivetrain. This creates all manner of unnecessary complexity, as embodied by Toyota’s Hybrid Synergy Drive. It is far simpler to make an electric vehicle and, for those who need extra range, include the option of a backup generator with a small gas tank. Suppose, for instance, that 360 days per year, you drive a maximum of 100 km per day, but 5 days a year, you have to travel up to 500 km to meetings or whatever. For those 5 days a year, it may make sense to spend an extra $1000 on a backup generator for your EV. Key point: this backup generator should be removable so its weight doesn’t decrease the efficiency of the EV for normal trips.

Conclusion

Most people thinking of electric vehicles as some kind of drawback requiring painful compromises. That’s bullshit. Electric vehicles are an overwhelming technological improvement over fossil-fuel burning cars. EVs are inherently more efficient, more powerful, faster, simpler, quieter and more versatile. The dimension on which EVs are inferior to gas-powered vehicles is refueling/recharging time, and this is easily managed for the vast majority of applications.

Related Posts:
Kavan’s Top 5 Ways to Save Energy – The Big Picture

5 Comments

  • H
    Posted July 27, 2009 at 7:33 am | Permalink

    “Most people thinking of electric vehicles as some kind of drawback requiring painful compromises.”

    Oil companies see them as their worst nightmare.

  • Kavan Wolfe
    Posted July 27, 2009 at 9:05 am | Permalink

    @H, true. I should have said, “most people thinking favorably of EVs…”

  • Posted September 27, 2009 at 6:38 pm | Permalink

    Don’t forget that when using a drivetrain with a central propellor shaft to transfer power, you have an added 30% power loss anticipated from that alone (check out at-the-wheel power figures versus at-the-flywheel). Also, you have the added problem of another component set to wear out and become stressed when you use a central drivetrain (especially from the super-high-torque electric motors). That’s exactly why diesel-electric locomotives use the system you’re referring to. It’s been blindingly obvious to me for years, but you’re right to point out the advantage of hub-motors. Also, they’d be much easier to add an Active Yaw Control system to, ala. Mitsubishi Lancer Evo’s (and it is a really cool system).

    On the gas tank vs. many batteries idea, you’re right in pointing it out – and it is so full of potential, too. The Mazda MX-5 is a great car because it is almost perfectly 50-50 weight balanced. Battery circuits that can be located remotely give us the chance to do the exact same thing with E.V.’s, thus building even more gut-wrenchingly awesome cars than we already have.

  • Kavan Wolfe
    Posted September 29, 2009 at 3:10 pm | Permalink

    @Aiden, excellent points. I never even considered the benefits of better balance until you mentioned it.

  • Posted November 8, 2010 at 9:08 am | Permalink

    electric motors can consume lots of electrical energy but they are very useful .

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