BU-1203: Electric Vehicle

Cars with electric powertrains have been around for more than 100 years. At the turn of the century, a car buyer had three choices of propulsion system: electric, steam, and internal combustion (IC) engine, of which the IC engine was the least common.

The electric cars appealed to the upper class and the vehicles were finished with fancy interiors and expensive materials. Although they were higher in price than the steam and gasoline-powered vehicles, the wealthy chose the electric car for its quiet and comfortable ride over the vibration, smell and high maintenance of gasoline-powered counterpart. Best of all, the electric vehicle (EV) did not require changing gears. Back then, the knuckle busting, wrist-wrenching chore of shifting gears was the most dreaded task for driving a gasoline-powered car. Nor did the EV need manual cranking to start the motor, a task the upper class did not want to be seen doing. Since the only good roads were in town, the limited range of the EV was no problem, and most of the driving was local commuting. Production of the EV peaked in 1912 and continued until the 1920s.

The battery of choice for the EV was lead acid. For an added fee, the buyer could fit the Detroit Electric with a nickel-iron (NiFe) battery, a technology Thomas Edison promoted. NiFe had a cell voltage of 1.2V, was robust and could endure overcharging and repeated full discharging. Being a good businessman, Edison continued to promote NiFe over lead acid by boasting its good performance at subfreezing and hot temperatures. Then in 1914, a devastating fire destroyed the Edison factory and the popularity for this battery began to decline. On a purely technological level, NiFe provided only a slightly better specific energy to lead acid and was expensive to manufacture. In addition, the battery performed poorly at low temperatures and the self-discharge was 20–40 percent a month, considerably higher than lead acid.

The Detroit Electric, one of the most popular EVs then, was said to get 130km (80 miles) between battery charges. Its top speed was 32km/h (20mph), a pace considered adequate for driving. Physicians and women were the main buyers. Thomas Edison, John D. Rockefeller, Jr. and Clara Ford, the wife of Henry Ford, drove Detroit Electrics. Figure 1 shows Thomas Edison with his 1914 Detroit Electric model.

Thomas Edison with a 1914 Detroit Electric, model 47

 

Figure 1:
Thomas
Edison with a 1914 Detroit Electric, model 47

Thomas Edison felt that nickel-iron was superior to lead acid for the EV and promoted his more expensive batteries.

Courtesy of National Museum of American History

Henry Ford’s mass-production and cost-cutting measures in 1912 were not the only reason for the shift towards gasoline-powered cars. The invention of the starter motor, the need to travel longer distances, and the discovery of Texas crude oil made the IC engine more attractive and affordable to the general public.

The EV became a thing of the past until the early 1990s when the California Air Resources Board (CARB) began pushing for more fuel-efficient and lower-emission vehicles. It was the CARB zero-emission policy that prompted General Motors to produce the EV1. Available for lease between 1996–1999, the EV1 initially ran on an 18kWh lead acid battery. The lead acid was later replaced with a 26kWh NiMH pack. Although the NiMH gave an impressive driving range of 260km (160 miles), the EV1 was not without problems. Manufacturing costs rose to three times the cost of a regular gasoline-powered car, and in 2001 politicians changed the CARB requirements, which prompted General Motors to withdraw the EV1, to the dismay of many owners. The 2006 documentary film Who Killed the Electric Car? gives a mixed impression of government-initiated programs for cleaner transportation.

To match the range of an IC-powered vehicle, the EV needs a battery capable of delivering 25–40kWh. This is twice the battery size of a PHEV and 10 times that of the HEV. The electro-chemical battery is not the only expense added to the EV; the power electronics to manage the battery make up a large part of the vehicle cost. An EV without a battery is roughly the same cost as a traditional gasoline-powered car. Figure 2 shows the battery of the Nissan Leaf as part of the under-chassis installation.

Cutaway battery of Nissan Leaf electric vehicle

Figure 2: Cutaway battery of Nissan Leaf electric vehicle. The Leaf includes a 24kWh lithium-ion battery with a city driving range of 160km (100 miles). The battery fits under the floor of the car, weighs 272kg (600lb) and is estimated to cost $15,600 (2010).

Courtesy of Nissan Motors

A valid concern with the EV is the limited driving range, especially in cold and hot weather. Designed to go 160km (100 miles) on a charge, a BMW Mini E traveled about half that distance in cold weather before running out of power. Additional energy is drawn to heat the cabin and battery performance drops in cold temperatures. While thermal technologies are making advances, achieving a comfortable cabin environment remains an issue with most EV designs. To conserve energy, EV drivers use the heat and air-conditioning sparingly and drive in a reasonable manner.

The Mini E takes 6–8 hours to fully charge the battery on a regular 115VAC outlet. High-power outlets (220–240VAC) can reduce the charge time to 3–5 hours, and high-power public fill-up stations can charge a battery in two hours. In most cases it’s the available electrical outlet and not the battery that governs charge times. Charging a 40kWh battery in six minutes, as some battery manufacturers might claim possible, would require 400kW of power. An ordinary 115VAC electrical outlet provides only 1.5kW, and a 230VAC, 40A kitchen stove outlet delivers 9kW. (The electric kitchen stove is often the household appliance that draws the most power. It feeds off a 230VAC, 40-ampere circuit.)

Car manufacturer Tesla Motors focuses on building EVs that generate zero emissions with very high performance. Its electric Roadster boasts a zero-to-96km (zero-to-60 mp) acceleration of 3.9 seconds. The 7,000 Li-ion cells store 53kWh of electrical power and deliver a driving range of 320km (200 miles). Liquid cooling prevents the cells from exceeding 35°C (95°F). To achieve the five-year warranty, Tesla charges the Li-cobalt cells to only 4.10V instead of 4.20V/cell. The electronics circuits inhibit charging at freezing temperatures. At $130,000, this car turns heads and becomes a discussion item, however, the $40,000 cost of a replacement battery could cause concern for long-term Tesla owners.

A battery for the electric powertrain currently costs between $1,000 and $1,200 per kWh. According to The Boston Consulting Group (BCG), relief is in sight. BCG claims that the price of Li-ion will fall to $750 per kWh within the next decade. Meanwhile, batteries for consumer electronics are only US$250–400 per kWh. High volume, automated manufacturing, lower safety requirements and shorter calendar life make this low price possible. BCG predicts that Li-ion batteries for the powertrain will eventually match these consumer prices, and the cost of a 15kWh battery will drop to about $6,000 from $16,000.

The largest decrease in battery prices is expected to occur between now and 2020, with a more gradual decline thereafter. According to BCG, the anticipated calendar life of the battery will be 10–15 years. E-One Moli Energy, a manufacturer of lithium-ion cells for power tools and electric vehicles, points out that the cost of Li-ion can be reduced to $400 per kWh in high volume, however, the peripheral electronics managing the battery, including heating and cooling, will remain high, essentially doubling the price of a pack. Reductions are also possible here, and E-One Moli Energy predicts that the electronics will only make up 20 percent of the cost of an EV battery in five years. These forecasts are speculative, and other analysts express concern that the carmakers may not be able to achieve the long-term cost target without a major breakthrough in battery technology. They say that the current battery cost is 3 to 5 times too high to appeal to the consumer market.

On the surface, driving on electricity is cheaper than burning gasoline but today’s low fuel prices, uncertainty about the battery’s service life, along with unknown abuse tolerances and high replacement costs, will reduce the incentive for buyers to switch from a proven concept to an electric vehicle. If a driver wants the 500km range between fill-ups that is achievable with a gasoline-powered car,the battery would need a capacity of 75kWh according toTechnology Roadmaps Electric and Plug-in Hybrid Electric Vehicles (EV/PHEV). At an estimated $400 price tag per kWh, such a battery would cost over $30,000 and weigh nearly a ton.

Technology Roadmap compares the energy consumption and cost of gasoline versus electric propulsion as follows: An EV requires between 150 and 200Wh per km depending on speed and terrain. At a consumption of 200Wh/km and an electricity price of $0.15 per kWh, the energy cost to drive an EV translates to $0.03 per km. This compares to $0.06 per km for an equal-size gasoline-powered car and $0.05 per km for diesel. The price estimations exclude equipment costs, service and eventual replacement of the battery and IC engine.

To prepare for the EV market, researchers and battery manufacturers have invested significant resources to develop better battery technologies, and many are taking advantage of generous government incentives. But there is a danger. For the sake of optimal specific energy, some start-up companies are experimenting with aggressive design concepts using volatile chemicals that compromise safety. They may push the envelope by announcing impressive advances, emphasizing only the pros and squelching the cons. Such behavior will get media attention and entice venture capitalists to invest, however, hype contributes little in finding a solution that will improve existing battery technologies.

The battery will determine the success of the EV, and until improvements are achieved in terms of higher specific energy, longer service life and lower cost, the electric powertrain may be limited to a niche market. While governments spend large sums in the hope of improving current battery technologies, we must realize that the electrochemical battery has limitations. This was made evident when motorists tested eight current and future models with electric powertrains and attained driving ranges that were one-third less than estimated. Table 3 lists a rundown of range and charge times. The electric cars were tested in real-life conditions on highways, over mountain passes and under winter conditions in 2010.
 

Electric vehicle

Battery

Range
advertised

Range
in real world

Charge times

BMW
Mini E

35kWh, air cooled; 18650 cells; NMC 355V, 96s53p

250km,
156 miles

153km, 96 miles;
112km, 70 miles
below freezing

26h at 115VAC;
4.5h at 230V, 32A

Chevy Volt

16kWh, liquid cooled
Li-manganese, 181kg (400lb)

64km,
40 miles

45km, 28 miles;
149hp electric &
1.4 liter IC engine

10h at 115VAC;
4h at 230VAC

Toyota plug-in Prius

3 Li-ion packs, one for hybrid; two for EV, 42 temp sensors

20km,
13 miles

N/A;
80hp electric &
98hp IC engine

3h at 115VAC;
1.5h min 230VAC

Mitsubishi iMiEV

16kWh; 88 cells, 4-cell modules; Li-ion; 109Wh/kg; 330V

128km,
80 miles

88km, 55 miles;
highway speed, mountain pass

13h at 115VAC;
7h at 230VAC

Nissan LEAF

24kWh; Li-manganese, 192 cells; 80Wh/kg, air cooled; 272kg (600lb)

160km,
100 miles

100km, 62 miles
at highway speed with heater on

8h at 230VAC;
30 min high ampere

Tesla Roadster

56kWh, 6,831 Li-cobalt computer cells; liquid cooled

352km,
220 miles

224km, 140 miles;
172km, 108 miles driven sports car

3.5h at 230VAC high ampere

Think City

24.5kW, Li-ion or sodium-based

160km,
100 miles

N/A. Sodium-type has few problems

8h at 115VAC

Smart
Fortwo ED

16.5kWh; cylindrical
Li-ion (computer cells), made by Tesla Motors

136km,
85 miles

Less than predicted

8h at 115VAC
3.5H at 230VAC

Table 3: Electric vehicles with battery type and driving range (2010)
The travel distance is less than advertised; battery aging will shorten the range further.

To make the electric vehicle affordable in the near future, early models will need to be light and restricted to short driving distances of 160km (100 miles) or less. Battery weight and cost will set these limitations. The successful EV will likely be a subcompact commuter car owned by drivers who adhere to a tightly regimented driving routine and follow disciplined recharging schedules. If the battery delivers as promised, these drivers will indeed realize cost savings and reduce greenhouse gases. Another benefit is reduced noise on city streets.

The environmental benefit of driving an EV is limited unless renewable resources provide electricity to charge the batteries. Burning coal and fossil fuel to generate electricity simply shifts pollution out of congested cities to the countryside. The electricity in the USA is being generated by burning coal (50%), natural gas (20%) and nuclear (20%). Renewable resources to generate electricity are hydro (8%) and solar and wind (2%). One of the advantages of the EV is that it can be charged at night when the power grid has extra capacity.

Going electric may also beg the question, “Without fuel tax revenue, who will pay for road construction and maintenance?” Roads cost governments billions to build and repair, and EV drivers are entitled to use them virtually for free. Higher taxes would eventually need to cover these expenses. This poses an unfair burden for commuters using public transportation. They pay double: the tax to pay for highways and the fare for the train.

The high cost of the EV against the lure of cheap and readily available fossil fuel will make the transition to a cleaner way of living difficult. Government subsidies may be needed to make “green” cars affordable to the masses. Many argue, however, that this handout of public money is unfair and suggest that the tax dollars should go to building more efficient public transportation systems.

The goal of governments should be to limit the number of cars on roads by offering different modes of transportation. Commuter trains are one of the most efficient ways of moving people comfortably and fast. Changing the focus away from cars and highways would, for the first time in 100 years, hand the cities back to the people who are the rightful owners. Such a change in direction would make our dwelling places more enjoyable, and future generations would thank their forefathers for the prudent planning. It’s worth noting that some of the most desirable cities were built before the invention of the car. Designers had the movement of people in mind. This, I believe, was done more out of necessity than foresight. Europe is leading in the list of the most desirable and livable cities; North America trails behind. 

Comments

On April 10, 2011 at 6:57am
Michael Thorn wrote:

An excellent overview free of hype and bias.I have owned an electric scooter for 3 years and it has been a steep learning curve including many times being stuck in the countryside looking for a friendly power point! I totally agree the application is limited to regular short trips well within the real range of the batteries.

On April 19, 2011 at 7:07pm
Lisza Bailey wrote:

The crowd who came to see Rolls-Royce’s Phantom, which was on display at the Geneva Motor show were in for a surprise to find batteries and electric motors under the bonnet, in the place of a well polished. These electric devices were used to run the 2.5 tone giant. This was just one of the many concept-cars that were present at the motor show. It just goes to show how sensitive the top guns in the industry are, to their contribution to global warming. Lesser luxurious models like Lexus (Toyota’s luxury brand) displayed seven units of gas-electric hybrid models for the motor show. While many other famous brands like Porsche, Land Rover, BMW and Mercedes too had variants of the hybrid on the show, what took the crowd by surprise was that the most affluent car brand in the world has started adopting go green philosophy.This is much related into this kind of review.

On November 16, 2011 at 5:22am
John Fetter wrote:

All vehicles require fuel. Surely the objective should be to find a way of maximizing the most efficient use of fuel, while at the same time minimizing the adverse effect on the environment? Whether this can be achieved by IC powered vehicles, hybrid or pure electric is immaterial.

Batteries can be very useful in some applications and absolutely useless in others. When ingenious people have tried as hard and as long as they have and the batteries still don’t give the required range, it is safe to assume they are not going to do so for quite a long time to come.

There are diesel-electric trains and diesel-electric ships. Why not diesel-electric automobiles and trucks. Not talking about hybrid.

Internal combustion engines are very inefficient when used over a relatively wide speed range. They become surprisingly efficient when run at constant speed, optimum horsepower. Easier to make totally silent, free of resonance and vibration.

Electric motors are generally super-efficient right down to relatively slow speeds.

The latest lead-acid batteries that are part battery, part super-capacitor are suitable for intermittent very high charge / discharge duty. They cost 10% of the price of lithium.

So the way to go is surely to have an IC engine that is run at a fixed speed, to charge the battery, when needed? Have a battery and electric motor(s) as high efficiency, infinitely variable speed transmission?

The vehicle becomes an electric with a thousand mile range. Get in, simply drive on battery. When the battery drops to 20% state-of-charge, the IC engine kicks in, tops the battery to 80% and stops. These are ballpark figures. The driver can modify to suit requirements. Peak horsepower delivered by electric motors, therefore IC engine needs to be rated at only 50%.

Quite a few shorter trips become pure electric. To plug in or not becomes optional. To use liquid fuel or not becomes optional.

On November 19, 2011 at 7:47pm
Edward Suchon wrote:

Great articles, thank you CADEX,  I like to study the periodic table, I read about one element every night, from the information that I read, there are alot of mines that have already closed ( cost vs. what actually is left to be had in the mine)  and the mines that are still running may run out in five to 30 years, some predict there’s just not enough of the certain metals needed for batteries to do a large changeover to electric cars. Of course new discoveries happen all over the world so this could change, fossil fuels nobody is really telling the truth of whats left underground, it’s to their advantage for controling what ever thier motives are for the day. The earth, and I can’t tell you where I read this but, fossil fuel maybe somthing the earth makes all the time and it’s not going to run dry!  anyways my point is, there maybe a limit to the metals available for producing huge quantites of all types of batteries in the future, recycling is a must! P.S. did you know there’s a way to use magnesium as a fuel? and after it’s used it turns into magnesium oxide, which can be turned back into magnesium with a solar pumped laser! we have many roads for energy to travel, lets do what we can with batteries and IC engines, and countinue to look at new sources of energy.

On April 26, 2012 at 6:36am
John Fetter wrote:

Pure battery suffers from an inherent problem that cannot be engineered away. Let’s for argument’s sake make an educated guess. The price of an advanced, pure electric, high performance battery: $15,000. Clever marketing people have long worked out that in order to get cars out of the showrooms, they can explain that the battery can be leased, thus averaging out the cost of the battery over X number of years.

The second hand car trade knows from very long experience how people, who trade in their cars, go about disguising problems. When the pure battery electrics start coming in, it will automatically be assumed the battery is about to collapse. The trade-in offer will be small change only because a new $15,000 battery will have to be fitted. This is a battery seller’s dream come true. Leases will now cost much more. Discounts will have dried up. Subsidies will have vanished.

It is difficult to see how this commercial problem can be overcome.

On September 7, 2013 at 2:33am
Andries Pienaar wrote:

If Oxidized Magnesium can be converted by sun (or other clean energy source) back to its metal state, then using Magnesium in the equation as Edward Suchon suggests may be a viable solution.

Magnesium could be used to extract Hydrogen from water to be used as a 100% clean fuel for an I.C. engine. Refueling would consist of trading in the Oxidized Magnesium for its metal counterpart and tanking up with water. There will be the challenge of safety issues but it should be possible to overcome them.

 

On September 7, 2013 at 3:29am
John Fetter wrote:

Andries Pienaar - Human beings have a tendency to synchronize their thinking. If the alternative fuel concepts that have been tried over and over and over in the past include the use of (1) batteries, (2) electric motors in parallel with IC engines and (3) hydrogen, the overwhelming majority of new ideas will focus on the use of variation of concepts 1, 2 and 3 and go absolutely nowhere.
Put 100 scientists and 100 lawyers in a big room and tell them they cannot come out until they can demonstrate that hydrogen can be made perfectly safe, they will do so. Put another 100 scientists and 100 lawyers in another big room, tell them they must prove hydrogen unsafe, they will do so.
One must always go back to basics and ask, what is the real objective? In the case of automobile transportation, surely it is minimum cost, maximum convenience, maximum performance, maximum energy conversion efficiency, maximum safety - in that order, if the concept is to enjoy universal acceptance?
I think a highly refined, constant speed IC engine that runs on hydrocarbon fuel, (easy to refuel, 100 year safety record), driving by a potent electric motor, via a battery-electric transmission, can do it better than any other technology.
If the space shuttle Challenger had been fueled by kerosene and oxygen, instead of hydrogen and oxygen, the astronauts would have been shaken but not stirred.

On May 26, 2014 at 9:49am
Immanuelsmith wrote:

Am a profession in engineree electrician “
i want to be employed

On May 29, 2014 at 4:59am
SREENIVASULU REDDY wrote:

I want to know why battery need charge for electric car batteries.
  i accepted for ignition starting purpose .
Car will be stop duriong drive condition. due to low charge of battery.
Why cont charge the battery during vehicle run time with alternator.