Why Don't We have "Battery Pack" Electric Cars?

Question

Most of the reasons I hear for why we don't yet have 100% electric cars center around the lack of an acceptable range for those cars.

Well similar reasoning used to be used to explain why electric hand tools like drills weren't that popular. But then they finally thought to develop quick change battery packs for those tools and all of a sudden battery powered tools became popular.

Well the same sort of reasoning should apply to electric cars. All you have to have is a chain of "battery stations" to do the charging and equip the electric cars with quick change battery packs to allow really fast (30 second?) battery changes. You drive as long and as fast as you want and you let the battery station take care of the charging. You could have maybe three sizes of battery A, B, and C and depending on how large your vehicle was.

Battery Pack means that the "pack" is charged seperately. It is charged slowly and carefully to maximize life and the efficiency of the system. It is only the swapping out operation that happens quickly (3o seconds perhaps?) When your old pack is discharged you can either charge it at home or work or just stop by the "battery station" where an already charged fresh pack will be waiting for you. Obviously they will charge you for this service but it should still be cheaper than paying for gas. Also since it uses electricity the source of electricity used to charge the pack can come from a clean sustainable "Green" source.

Answer 1

As an owner of an electric car, I can answer your questions from a unique perspective. It turns out that we DO have 'battery pack' cars, and always have had them - just not in large numbers.

Electric cars are clean (pollution from powerplants is far less than what comes out of a car's tailpipe), mechanically simple (electric motors have only one moving part), and recent battery advances are now giving them decent driving ranges. The new 'Tesla' electric sports car goes 250 miles per charge, and charges in only 3-1/2 hours. The electricity to drive it is only a penny per mile.
.
The exchangable battery pack idea has been tried - a forklift would be used to switch out the heavy battery packs. Also tried back in 1980 was a unique battery design that enabled just the electrolyte (the battery fluid) to be pumped out and exchanged for charged electrolyte.
.
The most promising new technology is the 'ultracapacitor'. A capacitor stores electricity in an entirely different way from a battery - it can be charged nearly instantaneously. And ultracapacitors will be able to hold twice the power - double the driving range - of the best batteries available now. (See references.)

Answer 2

Read the section of the linked PopSci article labeled "Rev Up Our Hybrid Rides". It is about a plug-in style hybrid that can increase gas mileage substantially (I think they will be a good substitute until pure electric vehicles improve). You might find the other article sections interesting too.

To your question at hand, I think you are correct that the prototype electric cars of the 90's had pretty poor operating range before requiring a recharge. Whoever "killed" the electric car killed off a weak link in the automobile chain anyway. Nobody really wanted to buy an inconvenient electric car. I'm sure they will get better though, thanks to engineers the world over.

But your idea is an interesting one. If people could own a set of spare batteries, they could keep some charging while they are at work or something. They could also keep a few charged batteries in the trunk as spares in case they run low on electricity.

The problems to be solved are: battery size/weight and creating some sort of quick disconnect mechanism. If the batteries are too heavy or too inconvenient to change, people won't go for the idea and would prefer just to have a permanent set of batteries that can charge overnight when plugged in.

And while I agree that electric vehicles simply shift the energy burden to power stations, the electric power grid is a much more efficient means of distribution than gas distribution. While power lines and equipment have some resistive losses and other miscellaneous losses, the transfer of power is pretty darn clean, efficient and easy to access. Gas, on the other hand, requires semi-trucks or other transportation vehicles to traverse the country/world.

The power plants are still using fossil fuels, but we are shifting the dirty part of millions of vehicles into a much smaller number of power plants that use the energy in very large bulk quantities. It is much easier to enforce emissions standards on a relatively small number of plants than a huge number of automobiles. Furthermore, power plants can make use of renewable energy much more efficiently by the fact that they can buy the energy source in huge bulk quantities. Wind power, solar power, hydro, nuclear etc do not transfer well at all to individual vehicles, but the power from those sources can be converted into electricity on a large scale and distributed to individual electric cars with ease via the power grid.

Answer 3

Using just electricity to power up a car require a large heavy battery pack. And to improve efficiency you probably want to use chemisty with high power density such as LiIon or LiIon polymer, which raises safety issue (you need protection circuitry to make sure you don't overcharge or undercharge the cells). And your pack is probably going to be high voltage (up to 200-300V) to provide the best efficiency for your electric motor, so another safety issue there. Charging would take some time but shouldn't be that long, a few hours, but you will have to find a way to charge them if you are to drive continuously for a long time.

To give you some perspective on electric car, I am actually an undergrad student who is developing solar car. The car is 100% electric and is 100% solar powered. We have to use 600+ LiIon cells for our battery pack @ 100Vdc. When we hook up the solar array we can continuously charge the pack while we are driving, but when we are not charging, we can drive the car for about 4 hours.. mainly because our car is so aerodynamic.

Answer 4

The battery packs would be too expensive for one and too heavy. I fly small electric model airplanes. A typical Ni-MH 8 cell pack of about 500mAH costs about $20 - $30 and weighs about 5 oz. A battery pack like that for a car would cost several thousand dollars. Hybrids already use this kind of battery and the packs usually cost around $3000, although there is one with a $7500 battery pack. I don't know about the weight of these packs, but I would guess at roughly 1,000 pounds. My little packs for my planes take about 30 min to charge. Batteries for a car are much larger...overnight charge.
You can buy electric cars from several different companies. The largest provider is Zap!

Answer 5

With current technology, 30 seconds will not charge any battery of significance. I'd venture to say even 30 minutes would not be enough for a battery pack capable of operating a car.

There are also quick-charge chargers, but these are incredibly destructive to the batteries themselves. Ask any kid with a remote control car.

Battery technology has made incredible strides, which is why there are now battery-powered devices that were unfathomable a decade or two ago. Technology is still evolving, so in time this certainly could be possible.

Answer 6

Dude there is A LOT of developmental work that has to go into quick charge packs. I'm in the battery industry trust me. The batteries of old would not hold up to the rapid charge of toady’s batteries. It not only comes down to being able to charge the pack quickly but they also need to be efficient. Meaning the pack need to give up all the energy you put into the pack. Also it has to be able to do so for many many cycles. There are hundreds of companies working on these applications and it is still going to take years.

Answer 7

Because battery pack are normally heavy. Therefore, by just using a pure electric car, the power would be drained quickly because you use more energy. Unlike the hybrid cars, the gas engine is still the main source of energy...electric motor only helps a bit.

Answer 8

Existing electric cars are not very popular because of low maximum speeds and their low range between charging up the batteries. I think your idea has merit particularly if low carbon sources of electricity become prevalent. The initial cost of installing equipment to handle battery packs (they are heavy) would be high and some initial financial incentives would likely be necessary to pump prime the development of the infrastructure.

(I assume you mean some sort of swap arrangement where a depleted battery is swapped for a fully charged one)

Answer 9

Why should we?

Electric cars still pollute...they do it at the power plant where the electricity is made.

They also aren't guaranteed to be cheaper per mile. Hybrids actually are at a maximum for fuel efficiency b/c they recover energy from the engine.

The technology will also drive up the price of the vehicle.

So the answer to your question is, we don't have them b/c there is currently no good reason to have them.

This could change, but the main driver would be cheap, clean electricity.