January 12, 2009
Lithium Batteries For Cars Still Pretty Heavy

Are we just waiting for battery cost to drop low enough to make pure electric cars feasible? Doesn't look that way. The forthcoming GM Chevy Volt pluggable hybrid which will go 40 miles on an electric charge will have a 400 pound battery.

Because the battery packs are about 6 feet (1.82 meters) long and weigh roughly 400 pounds (181 kilograms), the automaker wants them close to the carís assembly site.

That puts it at 10 lbs per mile. So in order to have a 400 mile range (which many gasoline cars have) 4000 lbs of battery would be required. The net gain in weight would be smaller since a gasoline tank, internal combustion engine, and some other parts would be absent. But the car would still be very heavy and would lose some energy efficiency and acceleration due to the weight.

At 6.3 lbs per gallon of gasoline a 40 mpg car can go 400 miles on a mere 63 pounds of fuel. Hydrocarbons offer big advantages for energy storage.

A more judicious use of batteries can actually boost range substantially. For example, the 2010 Ford Fusion Hybrid will have a 700 mile range in the city.

Aside: What do you call a Cadillac concept car built on the Chevrolet Volt pluggable hybrid? A Coupe de Volt. No, that's not GM's name for it.

I actually think pure electric cars have a future, even with the current energy storage capacities of lithium ion batteries. Some usage patterns work with the latest batteries. Short range electric trucks for use in the ports of Long Beach and Los Angeles make great sense as a way to get rid of dirty old polluting diesel trucks. Some uses of cars also fit with current battery limits. Ford is planning an electric car with only 100 mile range.

The second is a small battery-electric passenger car made in conjunction with Magna International. The car, which is scheduled for production in 2011, will be powered by lithium-ion batteries and have a range of up to 100 miles on a single charge, Ford said.

Ford wants to get electric cars into use as taxis to substitute for Crown Victorias. Each taxi trip tends to be pretty short range and 100 mile range would allow for 5, 10, 20 taxi trips. But how quickly can these taxis get recharged and how many places around a city could be set up as recharging stations? Anyone have any details on this?

What all this means for the future: as battery costs decline the per mile cost of commuter driving will drop relative to the cost of longer range trips. Basically, batteries will move you shorter distances while liquid fuels will move you longer distances. That'll be true in the air and on the ground. The only exception to that rule: trains. Once oil production starts declining we'll probably see train electrification. That works because electric trains can get their power from that run along the train tracks.

Update: Ford expects their 100 mile car will require 6 hours to recharge!

Most of the prospective electric models need to be charged for several hours to cover a dayís worth of driving. Ford estimates that its car will need at least a six-hour charge to travel 100 miles.

How many miles a day does the average taxi driver drive?

Share |      Randall Parker, 2009 January 12 10:58 PM  Energy Batteries

Jerry Martinson said at January 12, 2009 11:52 PM:

I think dreyage in ports is the lowest hanging fruit for an all-electric vehicle.

Train electrification in the US will be problematic unless the feds allow freight and passenger traffic to co-exist for electric track. I'm not sure what the objection is but currently it is not allowed. Kind of a bummer for Caltrain electrification as the stimulus boondoggle money is likely to pass them by since this means that the project not "shovel ready".

Brett Bellmore said at January 13, 2009 4:35 AM:

I think one of the keys to electric car practicality is to standardize the batteries to the point where "gas stations" can do quick swaps, and charge the batteries outside the cars. However, this would require a degree of cooperation between automotive companies which would have anti-trust implications, unless enabled by law.

Wolf-Dog said at January 13, 2009 4:38 AM:

While many gasoline cars have a range of 400 miles, many don't. In fact, many gasoline cars have a range of about 250 to 300 miles. Thus once the pure electric cars have a range of 200 miles, this will become quite acceptable. In fact, the business model of the Project Better Place is to build charging pods in every parking space in every street, AND also a reasonable number of batter swapping stations that will have the role of gas stations.


The battery swapping stations are going to be for people who do not have the time to charge their batteries. The cars that this business model (ALREADY adopted by Denmark, Hawaii, and the Bay Area) that will have its infrastructure ready by 2011-1012, will have a range of only 100 miles with lithium-ion batteries.

Renault-Nissan already agreed to mass produce electric cars WITHOUT BATTERIES for the Project Better Place by 2011.

The idea of swapping batteries is not new, but the Project Better Place is being very innovative in its organization, in the sense that this corporation will take the responsibility of servicing batteries, so that the electric car buyer buys the car WITHOUT BATTERY, so that the electric car itself would cost $12,000 (normal size car with 5 seats and 4 doors) because pure electric cars have a lot less components, and only the battery component is expensive.) Then, the electric company will only RENT the battery to car drivers, and then the cost of driving will be 8 cents per mile (5 cents per mile for the cost of the battery per mile, plus 2 to 3 cents per mile for electricity). This business model of 8 cents per mile is competitive with gasoline prices at $2 per gallon, but if this economic depression
drives the price of gasoline below $1.5 per gallon for several years, then this will not work. As long as the price of gasoline is $2 per gallon or higher, then this business model is sound.

Separately, in addition to lithium-ion batteries, there are already zinc-air batteries,which have an energy density of nearly 400 Wh/kg, which is almost twice that of lithium-ion batteries. The trouble with zinc-air batteries is that they cannot be charged at home, the "charging" is done at the service station by replacing the oxidized zinc with de-oxidized zing (the de-oxidation of zinc is done electrically, which is tantamount to re-charging it). This means swapping batteries at the stations, which can be a nuisance for some people, but note that the range of zinc-air battery powered cars would easily by at least 250 to 300 miles per battery swap.

Note that ALREADY a zinc-air battery powered bus was demonstrated in New York. This bus has a range of 100 miles, and during the demonstration the bus was full of people and its air-conditioner was on:


The buses and trucks can start using the zinc-air battery swapping model, because the itinerary of buses and trucks is more predictable, and given that zinc-air batteries are much cheaper than the lithium-ion batteries, the companies that operate buses and trucks will find this economically superior to diesel fuel. If Obama is smart, he would quickly start implementing this business model for both cars and buses and trucks.

JAY said at January 13, 2009 5:29 AM:

World oil production is not peaking. In fact, new techniques for extraction are making more and more oil available at lower prices. Electric cars will be a passing fad and will never be sold in serious volume.

tom bri said at January 13, 2009 6:04 AM:

I drive a 9000 pound vehicle for work. 2000 pounds of that is the battery. We swap out batteries about once per ten hour shift.

Wolf-Dog said at January 13, 2009 6:27 AM:

If you think that the peak oil theory is false, Randall Parker is delegated to answer this question for you. But at the same time, the annual trade deficit is nearly $700 billion per year (6 % of the GDP), and the oil component of the annual trade deficit is nearly $400 billion. At this rate, nobody will accept the our trade deficit dollars in exchange for nothing, which is essentially printed fake money, and this will be the end of the United States, unless, the trade deficit is brought under control at some point. Oil independence is thus obligatory for the United States.

pond said at January 13, 2009 7:27 AM:

While I still maintain that electric rail is our only option going forward that makes any sort of energy or fiscal sense, electricity makes of cars the best that can be made of a bad bargain.

The 'better place' idea strikes me as the best way for automakers to handle the transition: design a plug for the cars that battery packs will connect to, make it standard and free to license, and then just sell electric cars with no batteries. Allow third parties to compete to offer batteries in different capacities, chemistries, etc. This immediately makes the electric car cheap to sell, cheap to design, and will encourage faster development of the battery and fuel cell technologies than is possible if it remains restricted to a handful of carmakers and their partners.

K said at January 13, 2009 9:44 AM:

Going for electric taxis definitely offers advantages. A taxi could recharge while waiting, electrical stations can be easily built around the city. Until then I am a fan of the simple CNG ICU for taxis; CNG does cut trunk space.

Big taxi fleets might prove the best fit for the fuel cell. No pollution and a lot of miles to defray the cost of the cells and the hydrogen stations. OTOH real world fuel cell trials in bus fleets have not been encouraging. Many cells failed too soon.

Jerry and others are right, places such as ports, rail car loading, airport shuttles, taxis, and buses are the place to bring in electric vehicles and new technologies.

Talk of electric trains bothers me simply because of our atrocious pattern of cost overruns when city and regional planners deal with light rail or anything akin to it. Billions are spent to build systems that then lose more money every day, often with no detectable ridership.

Given that record I certainly hope Obama's programs will not just hand billions to any city that can spell "light rail" on an application.

Railroad freight is another matter and electrification is a desirable direction. The amount of freight to be carried is more easily known than the number of riders. Time of movement is not critical. And the right-of-ways are already tracked, so electrification should be effective and costs more accurately known.

Nick G said at January 14, 2009 9:45 AM:

Randall, I agree with the short/long distance split, but it's really cost, not weight that is the problem. The Volt only uses 50% of the battery capacity - a 300 mile range vehicle could use 100%, because it would be used so rarely (and because 50% is probably too conservative even for the Volt's range). So, 10 lbs per mile overstates things - it's closer to 5 lbs/mile.

Also, with regenerative braking the efficiency penalty for weight is small.

Ships are another application for diesel/electric plubin hybrids - coal powered ships stopped much more often than diesel ships, and plugin ships could do that as well.

Nick G said at January 14, 2009 10:38 AM:

Although, to be fair, I have to admit that 1,500 lbs of batteries would be pretty inconvenient.

I think the important thing is that extended range EV's/plugins like the Volt will work extremely well in the short term (reducing fuel consumption by 80-99%, depending on travel patterns), and that batteries will improve on both cost and weight in the longterm.

Joe said at January 14, 2009 10:41 AM:

There is quite a bit of research being done with very light batteries. Unfortunately, while some have worked in the lab, they aren't practical to manufacture or use in real world conditions. Were I in charge of handing out money to improve energy technology it would be to improve pebble bed nuclear reactors, reusing nuclear fuel and developing lighter batteries (this goes beyond cars--imagine cutting your laptop battery weight by even 50%!)

Randall Parker said at January 16, 2009 7:56 PM:


My point (which I didn't make clearly enough) is that even if we solve the cost problem we will still be up against a weight problem.

50% discharge: Why does GM do that again? Battery life? Or other?

PHEVs: But I think it'll be annoying to be frequently plugging in one's car to recharge.


We still do not know how much more lightweight batteries are going to get. Nanotech might allow a big increase in battery performance. I hope so.

Nick G said at January 19, 2009 11:18 AM:

"even if we solve the cost problem we will still be up against a weight problem."

Well, my point was that if we solve the cost problem, the weight problem won't be very important. Consider: the Tesla carries 900 lbs of batteries, yet gets 250 mile range, and 4 seconds 0-60. If cost were dramatically lowered, weight would be no problem for the Tesla.

"50% discharge: Why does GM do that again?"

Primarily to ensure that the battery lasts the 10 year warranty. Some users will use the full capacity of the battery daily (a few will use more, like taxis). 1st, GM is being very conservative. 2nd, a vehicle with 250+ range would use the full capacity very rarely.

"I think it'll be annoying to be frequently plugging in one's car to recharge."

Could be. Depends on design. 1st, you almost entirely avoid annoying and potentially lengthy stops for gas. 2nd, surely an automatic docking system will be designed eventually.

osagi said at February 28, 2009 12:45 AM:

why aren't automotive engineers today isn't paying more attention on hydraulic cars?

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