Electric car

An electric car is a plug-in battery powered automobile which is propelled by electric motor(s). Electric cars were popular in the late-19th century and early 20th century, until advances in internal combustion engine technology and mass production of cheaper gasoline vehicles led to a decline in the use of electric drive vehicle(SONY Vaio VGN-NW Battery). The energy crises of the 1970s and 80s brought a short lived interest in electric cars, but in the mid 2000s took place a renewed interest in the production of electric cars due mainly to concerns about rapidly increasing oil prices and the need to curb greenhouse gas emissions(SONY Vaio VGN-NW21EF/S Battery). As of early 2011 series production models available in some countries include the Tesla Roadster, REVAi, Buddy, Mitsubishi i MiEV, Th!nk City, and Nissan Leaf(SONY Vaio VGN-NW21JF Battery).

Electric cars have several potential benefits as compared to conventional internal combustion automobiles that include a significant reduction of urban air pollution as they do not emit harmful tailpipe pollutants from the onboard source of power at the point of operation (zero tail pipe emissions) (SONY Vaio VGN-NW21MF Battery); reduced greenhouse gas emissions from the onboard source of power depending on the fuel and technology used for electricity generation to charge the batteries; and less dependence on foreign oil, which for the United States, other developedand emerging countries is cause of concerns about their vulnerability to price shocks and supply disruption(SONY Vaio VGN-NW21MF/W Battery). Also for manydeveloping countries, and particularly for the poorest in Africa, high oil prices have an adverse impact on their balance of payments, hindering their economic growth.

Despite their potential benefits, widespread adoption of electric cars faces several barriers and limitations(SONY Vaio VGN-NW31EF/W Battery). As of 2011 electric cars are significantly more expensive than conventional internal combustion engine vehicles and hybrid electric vehicles due to the additional cost of their lithium-ion battery pack. Other factors discouraging the adoption of electric cars are the lack of public and private recharging infrastructure and the driver's fear of the batteries running out energy before reaching their destination (SONY Vaio VGN-NW21ZF Battery) (range anxiety) due to the limited range of existing electric cars. Several governments have established policies and economic incentives to overcome existing barriers, to promote the sales of electric cars, and to fund further development of electric vehicles, more cost-effective battery technology and their components(SONY Vaio VGN-NW31JF Battery). The U.S. has pledged US$2.4 billion in federal grants for electric cars and batteries. China has announced it will provideUS$15 billion to initiate an electric car industry. Several national and local governments have established tax credits, subsidies, and other incentives to reduce the net purchase price of electric cars and other plug-ins(SONY Vaio VGN-NW320F/B Battery).

Etymology

Electric cars are a variety of electric vehicle (EV); the term "electric vehicle" refers to any vehicle that uses electric motors for propulsion, while "electric car" generally refers to road-going automobiles powered by electricity. While an electric car's power source is not explicitly an on-board battery(SONY Vaio VGN-NW320F/TC Battery), electric cars with motors powered by other energy sources are generally referred to by a different name: an electric car powered by sunlight is a solar car, and an electric car powered by a gasoline generator is a form of hybrid car. Thus, an electric car that derives its power from an on-board battery pack is a form of battery electric vehicle(BEV) (SONY Vaio VGN-NW35E Battery). Most often, the term "electric car" is used to refer to pure battery electric vehicles.

History

Electric cars enjoyed popularity between the mid-19th century and early 20th century, when electricity was among the preferred methods for automobile propulsion, providing a level of comfort and ease of operation that could not be achieved by the gasoline cars of the time(SONY Vaio VGN-NW11S/S Battery). Advances in internal combustion technology soon rendered this advantage moot; the greater range of gasoline cars, quicker refueling times, and growing petroleum infrastructure, along with the mass production of gasoline vehicles by companies such as the Ford Motor Company(SONY Vaio VGN-NW11Z/S Battery), which reduced prices of gasoline cars to less than half that of equivalent electric cars, led to a decline in the use of electric propulsion, effectively removing it from important markets such as the United States by the 1930s. However, in recent years, increased concerns over theenvironmental impact of gasoline cars(SONY Vaio VGN-NW11S/T Battery), along with reduced consumer ability to pay for fuel for gasoline cars, and the prospect of peak oil, has brought about renewed interest in electric cars, which are perceived to be more environmentally friendly and cheaper to maintain and run, despite high initial costs(SONY Vaio VGN-NW11Z/T Battery). Electric cars currently enjoy relative popularity in countries around the world, though they are notably absent from the roads of the United States, where electric cars briefly re-appeared in the late 90s as a response to changing government regulations(Dell Latitude E4300 battery).

1890s to 1900s: Early history

Before the pre-eminence of internal combustion engines, electric automobiles held many speed and distance records. Among the most notable of these records was the breaking of the 100 km/h (62 mph) speed barrier, by Camille Jenatzy on April 29, 1899 in his 'rocket-shaped' vehicle Jamais Contente, which reached a top speed of 105.88 km/h (65.79 mph). Before the 1920s(Dell Latitude 2110 battery), electric automobiles were competing with petroleum-fueled cars for urban use of a quality service car.

Proposed as early as 1896 in order to overcome the lack of recharging infrastructure, an exchangeable battery service was first put into practice by Hartford Electric Light Company for electric trucks(Dell Latitude 2100 battery). The vehicle owner purchased the vehicle from General Electric Company (GVC) without a battery and the electricity was purchased from Hartford Electric through an exchangeable battery. The owner paid a variable per-mile charge and a monthly service fee to cover maintenance and storage of the truck(Dell Latitude D830 battery). The service was provided between 1910 to 1924 and during that period covered more than 6 million miles. Beginning in 1917 a similar service was operated in Chicago for owners of Milburn Light Electric cars who also could buy the vehicle without the batteries(Dell LATITUDE D820 battery).

In 1897, electric vehicles found their first commercial application in the U.S. as a fleet of electrical New York City taxis, built by the Electric Carriage and Wagon Company of Philadelphia. Electric cars were produced in the US by Anthony Electric, Baker, Columbia, Anderson, Edison, Fritchle, Studebaker, Riker,Milburn, and others during the early 20th century(Dell Latitude D810 battery).

Despite their relatively slow speed, electric vehicles had a number of advantages over their early-1900s competitors. They did not have the vibration, smell, and noise associated with gasoline cars. They did not require gear changes, which for gasoline cars was the most difficult part of driving(Dell LATITUDE D800 battery). Electric cars found popularity among well-heeled customers who used them as city cars, where their limited range proved to be even less of a disadvantage. The cars were also preferred because they did not require a manual effort to start(Dell Latitude D630 battery), as did gasoline cars which featured a hand crank to start the engine. Electric cars were often marketed as suitable vehicles for women drivers due to this ease of operation.

In 1911, the New York Times stated that the electric car has long been recognized as "ideal" because it was cleaner(Dell Latitude D620 battery), quieter and much more economical than gasoline-powered cars. Reporting this in 2010, the Washington Post commented that "the same unreliability of electric car batteries that flummoxed Thomas Edison persists today."

1990s to present: Revival of mass interest

The energy crises of the 1970s and 80s brought about renewed interest in the perceived independence electric cars had from the fluctuations of the hydrocarbon energy market(Dell Latitude D610 battery). In the early 1990s, the California Air Resources Board (CARB), the government of California's began a push for more fuel-efficient, lower-emissions vehicles, with the ultimate goal being a move to zero-emissions vehicles such as electric vehicles. In response(Dell Latitude D600 battery), automakers developed electric models, including the Chrysler TEVan, Ford Ranger EV pickup truck, GM EV1 and S10 EVpickup, Honda EV Plushatchback, Nissan lithium-battery Altra EV miniwagon and Toyota RAV4 EV(Dell Latitude D520 battery).

An important goal for electric vehicles is overcoming the disparity between their costs of development, production, and operation, with respect to those of equivalent internal combustion engine vehicles (ICEVs) (Dell Latitude D510 battery).

Price

Electric cars are generally more expensive than gasoline cars. The primary reason is the high cost of car batteries. US and British car buyers seem to be unwilling to pay more for an electric car. This prohibits the mass transition from gasoline cars to electric cars(Dell Latitude D505 battery). A survey taken by Nielsen for the Financial Times has shown that 65 percent of Americans and 76 percent of Britons are not willing to pay more for an electric car above the price of a gasoline car. also a report by J.D. Power and Associates claims that about 50 percent of U.S(Dell Latitude D500 battery). car buyers are not even willing to spend more than US$5,000 on a green vehicle above the price of a petrol car despite their concern about the environment.

The Nissan LEAF is the most affordable five door family electric car in the U.S. at a price of US$32,780 going down to US$25,280 after federal tax rebate of US$7,500, going further down to US$20,280 after the US$5,000 tax rebate in California and similar incentives in other states(Dell Latitude D430 battery).

The Renault Fluence Z.E. five door family saloon electric car will be priced at less than US$20,000 before any U.S. federal and state tax rebates are applied. It will be sold without the battery thus the significant price difference. The customer will buy the Renault Fluence Z.E. with a contract to lease the battery from the company Better Place(Dell Latitude D420 battery).

The electric car company Tesla Motors is using laptop battery technology for the battery packs of their electric cars that are 3 to 4 times cheaper than dedicated electric car battery packs that other auto makers are using(Dell Latitude D410 battery). While dedicated battery packs cost $700–$800 per kilowatt hour, battery packs using small laptop cells cost about $200. That could potentially drive down the cost of electric cars that are using Tesla's battery technology such as the Toyota RAV4 EV and the Smart ED as well as their own upcoming 2014 models such as theModel X(Dell Latitude CPX battery).

Running costs and maintenance

Most of the running cost of an electric vehicle can be attributed to the maintenance and replacement of the battery pack because an electric vehicle has only around 5 moving parts in its engine, compared to a gasoline car that has hundreds of parts in its internal combustion engine(Dell Latitude CPI battery). Electric cars have expensive batteries that must be replaced but otherwise incur very low maintenance costs, particularly in the case of current Lithium based designs.

To calculate the cost per kilometer of an electric vehicle it is therefore necessary to assign a monetary value to the wear incurred on the battery(Dell Latitude C840 battery). This can be difficult due to the fact that it will have a slightly lower capacity each time it is charged and is only considered to be at the end of its life when the owner decides its performance is no longer acceptable. Even then an 'end of life' battery is not completely worthless as it can be re-purposed, recycled or used as a spare(Dell Latitude C810 battery).

Since a battery is made of many individual cells that do not necessarily wear evenly periodically replacing the worst of these can retain the vehicle's range.

The Tesla Roadster's very large battery pack is expected to last seven years with typical driving and costs US$12,000 when pre-purchased today(Dell Latitude C800 battery). Driving 40 miles (64 km) per day for seven years or 102,200 miles (164,500 km) leads to a battery consumption cost of US$0.1174 per 1 mile (1.6 km) or US$4.70 per 40 miles (64 km). The company Better Place provides another cost comparison as they anticipate meeting contractual obligations to deliver batteries as well as clean electricity to recharge the batteries at a total cost of US$0.08 per 1 mile (1.6 km) in 2010, US$0.04 per mile by 2015 and US$0.02 per mile by 2020(Dell Latitude C640 battery). 40 miles (64 km) of driving would initially cost US$3.20 and fall over time to US$0.80.

In 2010 the U.S. government estimated that a battery with a 100 miles (160 km) range would cost about US$33,000. Concerns remain about durability and longevity of the battery(Dell Latitude C610 battery).

Nissan estimates that the Leaf's 5 year operating cost will be US$1,800 versus US$6,000 for a gasoline car. The documentary film Who Killed the Electric Car? shows a comparison between the parts that require replacement in a gasoline powered cars and EV1s(Dell Latitude C600 battery), with the garages stating that they bring the electric cars in every 5,000 mi (8,000 km), rotate the tires, fill the windshield washer fluid and send them back out again.

Electricity vs. hydrocarbon fuel

"Fuel" cost comparison: the Tesla Roadster sport car's plug-to-wheel energy use is 280 W·h/mi(Dell Latitude C540 battery). In Northern California, the local electric utility company PG&E says that "The E-9 rate is mandatory for those customers that are currently on a residential electric rate and who plan on refueling an EV on their premises." Combining these two facts implies (Dell Latitude C510 battery)that driving a Tesla Roadster 40 miles (64 km) a day would use 11.2 kW·h of electricity costing between US$0.56 and US$3.18 depending on the time of day chosen for recharging. For comparison, driving an internal combustion engine-powered car the same 40 miles (64 km), at a mileage of 25 miles per US gallon (9.4 L/100 km; 30 mpg-imp) (Dell Latitude C500 battery), would use 1.6 US gallons (6.1 l; 1.3 imp gal) of fuel and, at a cost of US$4 per 1 US gallon (3.8 l; 0.83 imp gal), would cost US$6.40.

The Tesla Roadster uses about 17.4 kW·h/100 km (0.63 MJ/km; 0.280 kW·h/mi),[49] the EV1 used about 11 kW·h/100 km (0.40 MJ/km; 0.18 kW·h/mi) (Dell Latitude C400 battery).

Range and refuelling time

Cars with internal combustion engines can be considered to have indefinite range, as they can be refuelled very quickly almost anywhere. Electric cars often have less maximum range on one charge than cars powered by fossil fuels, and they can take considerable time to recharge(Dell Latitude 131L battery). This is a reason that many automakers marketed EVs as "daily drivers" suitable for city trips and other short hauls. The average American drives less than 40 miles (64 km) per day; so the GM EV1 would have been adequate for the daily driving needs of about 90% of U.S. consumers(Dell Latitude D400 battery). Nevertheless, people can be concerned that they would run out of energy from their battery before reaching their destination, a worry known as range anxiety.

The Tesla Roadster can travel 245 miles (394 km) per charge; more than double that of prototypes and evaluation fleet cars currently on the roads(Dell XPS 1647 battery). The Roadster can be fully recharged in about 3.5 hours from a 220-volt, 70-amp outlet which can be installed in a home.

One way automakers can extend the short range of electric vehicles is by building them with battery switch technology(Dell XPS 1645 battery). An EV with battery switch technology and a 100 miles (160 km) driving range will be able to go to a battery switch station and switch a depleted battery with a fully charged one in 59.1 seconds giving the EV an additional 100 miles (160 km) driving range(Dell XPS 1640 battery). The process is cleaner and faster than filling a tank with gasoline and the driver remains in the car the entire time, but because of the high investment cost, its economics are unclear. As of late 2010 there are only 2 companies with plans to integrate battery switching technology to their electric vehicles: Better Place and Tesla Motors(Dell XPS 16 battery). Better Place operated a battery-switch station in Japan until November 2010 and announced a commitment to open four battery switch stations in California, USA.

Another way is the installation of DC Fast Charging stations with high-speed charging capability from three-phase industrial outlets so that consumers could recharge the 100 mile battery of their electric vehicle to 80 percent in about 30 minutes(Dell XPS 13 battery). A nationwide fast charging infrastructure is currently being deployed in the US that by 2013 will cover the entire nation. DC Fast Chargers are going to be installed at 45 BPand ARCO locations and will be made available to the public as early as March 2011(Dell XPS M140 battery). The EV Project will deploy charge infrastructure in 16 cities and major metropolitan areas in six states. Nissan has announced that 200 of its dealers in Japan will install fast chargers for the December 2010 launch of its Leaf EV, with the goal of having fast chargers everywhere in Japan within a 25 mile radius(Dell Inspiron Mini 12 battery).

Pollution

Electric cars produce no pollution at the tailpipe which will contribute to cleaner air in cities, but their use increases demand for electricity generation. The amount of carbon dioxide emitted depends on the emission intensity of the power source used to charge the vehicle(Dell XPS M2010 battery), the efficiency of the said vehicle and the energy wasted in the charging process.

For mains electricity the emission intensity varies significantly per country and within a particular country it will vary depending on demand, the availability of renewable sources and the efficiency of the fossil fuel-based generation used at a given time(Dell XPS M1730 battery). Charging a vehicle using off-grid renewable energy yields very low carbon intensity (only that to produce and install the off-grid generation system e.g. domestic wind turbine).

An EV recharged from the existing US grid electricity emits about 115 grams of CO2 per kilometer driven (6.5 oz(CO2)/mi) (Dell XPS M1710 battery), whereas a conventional US-market gasoline powered car emits 250 g(CO2)/km (14 oz(CO2)/mi) (most from its tailpipe, some from the production and distribution of gasoline). The savings are questionable relative to hybrid or diesel cars (according to official British government testing(Dell XPS M170 battery), the most efficient European market cars are well below 115 grams of CO2 per kilometer driven, although a study in Scotland gave 149.5gCO2/km as the average for new cars in the UK), but would be more significant in countries with cleaner electric infrastructure(Dell XPS M1530 battery). In a worst-case scenario where incremental electricity demand would be met exclusively with coal, a 2009 study conducted by the World Wide Fund for Nature and IZES found that a mid-size EV would emit roughly 200 g(CO2)/km (11 oz(CO2)/mi) (Dell XPS 1340 battery), compared with an average of 170 g(CO2)/km (9.7 oz(CO2)/mi) for a gasoline-powered compact car. This study concluded that introducing 1 million EV cars to Germany would, in the best-case scenario, only reduce CO2 emissions by 0.1%, if nothing is done to upgrade the electricity infrastructure or manage demand(Dell XPS M1330 battery).

In France, which has a clean energy grid, CO2 emissions from electric car use would be about 12g per kilometer.

A study made in the UK in 2008 concluded that electric vehicles had the potential to cut down carbon dioxide and greenhouse gas emissions by at least 40%, even taking into account the emissions due to current electricity generation in the UK and emissions relating to the production and disposal of electric vehicles(Dell XPS M1210 battery).

Acceleration and drivetrain design

Electric motors can provide high power to weight ratios, and batteries can be designed to supply the large currents to support these motors.

Although some electric vehicles have very small motors, 15 kW (20 hp) or less and therefore have modest acceleration, many electric cars have large motors and brisk acceleration. In addition, the relatively constant torque of an electric motor(Dell INSPIRON MINI 9 battery), even at very low speeds tends to increase the acceleration performance of an electric vehicle relative to that of the same rated motor power internal combustion engine. Another early solution was American Motors’ experimental Amitron piggyback system of batteries with one type designed for sustained speeds while a different set boosted acceleration when needed(Dell STUDIO 1450 battery).

Electric vehicles can also use a direct motor-to-wheel configuration which increases the amount of available power. Having multiple motors connected directly to the wheels allows for each of the wheels to be used for both propulsion and as braking systems, thereby increasing traction. In some cases(Dell VOSTRO 1400 battery), the motor can be housed directly in the wheel, such as in the Whispering Wheel design, which lowers the vehicle's center of gravityand reduces the number of moving parts. When not fitted with an axle, differential, or transmission, electric vehicles have less drivetrain rotational inertia(Dell VOSTRO 1500 battery).

Transmission

A gearless or single gear design in some EVs eliminates the need for gear shifting, giving such vehicles both smoother acceleration and smoother braking. Because the torque of an electric motor is a function of current, not rotational speed(Dell XPS M1210 battery), electric vehicles have a high torque over a larger range of speeds during acceleration, as compared to an internal combustion engine. As there is no delay in developing torque in an EV, EV drivers report generally high satisfaction with acceleration(Dell XPS M1330 battery).

For example, the Venturi Fetish delivers supercar acceleration despite a relatively modest 220 kW (295 hp), and top speed of around 160 km/h (100 mph). Some DC motor-equipped drag racer EVs, have simple two-speed manual transmissions to improve top speed(Dell XPS 1340 battery). The Tesla Roadster 2.5 Sport can accelerate from 0 to 60 mph (97 km/h) in 3.7 seconds with a motor rated at 215 kW (288 hp).

Also the Wrightspeed X1 prototype created by Wrightspeed Inc is the worlds fastest street legal electric car. With an acceleration of 0-60 mph in 2.9 seconds the X1 has bested some of the worlds fastestsports cars(Dell XPS M1530 battery).

Energy efficiency

Internal combustion engines are relatively inefficient at converting on-board fuel energy to propulsion as most of the energy is wasted as heat. On the other hand, electric motors are more efficient in converting stored energy into driving a vehicle(Dell XPS M170 battery) , and electric drive vehicles do not consume energy while at rest or coasting, and some of the energy lost when braking is captured and reused through regenerative braking, which captures as much as one fifth of the energy normally lost during braking. Typically(Dell XPS M1710 battery), conventional gasoline engines effectively use only 15% of the fuel energy content to move the vehicle or to power accessories, and diesel engines can reach on-board efficiencies of 20%, while electric drive vehicles have on-board efficiency of around 80%(Dell XPS M1730 battery).

Production and conversion electric cars typically use 10 to 23 kW·h/100 km (0.17 to 0.37 kW·h/mi). Approximately 20% of this power consumption is due to inefficiencies in charging the batteries. Tesla Motors indicates that the vehicle efficiency (including charging inefficiencies) of their lithium-ion battery powered vehicle is 12.7 kW·h/100 km (0.21 kW·h/mi) and the well-to-wheels efficiency (assuming the electricity is generated from natural gas) is 24.4 kW·h/100 km (0.39 kW·h/mi) (Dell XPS M2010 battery).

Safety

The safety issues of BEVs are largely dealt with by the international standard ISO 6469. This document is divided in three parts dealing with specific issues:

On-board electrical energy storage, i.e. the battery

Functional safety means and protection against failures

Protection of persons against electrical hazards(Dell Inspiron Mini 12 battery).

Firefighters and rescue personnel receive special training to deal with the higher voltages and chemicals encountered in electric and hybrid electric vehicle accidents. While BEV accidents may present unusual problems, such as fires and fumes resulting from rapid battery discharge(SONY VGP-BPS9A/S battery), there is apparently no available information regarding whether they are inherently more or less dangerous than gasoline or diesel internal combustion vehicles which carry flammable fuels.

Vehicle safety

Great effort is taken to keep the mass of an electric vehicle as low as possible to improve its range and endurance(SONY VGP-BPS9/B battery). However, the weight and bulk of the batteries themselves usually makes an EV heavier than a comparable gasoline vehicle, reducing range and leading to longer braking distances; it also has less interior space. However, in a collision, the occupants of a heavy vehicle will, on average, suffer fewer and less serious injuries than the occupants of a lighter vehicle(SONY VGP-BPS9/S battery); therefore, the additional weight brings safety benefits despite having a negative effect on the car's performance. An accident in a 2,000 lb (900 kg) vehicle will on average cause about 50% more injuries to its occupants than a 3,000 lb (1,400 kg) vehicle(SONY VGP-BPS9A battery). In a single car accident, and for the other car in a two car accident, the increased mass causes an increase in accelerations and hence an increase in the severity of the accident. Some electric cars use low rolling resistance tires, which typically offer less grip than normal tires(SONY VGP-BPS9A/B battery). Many electric cars have a small, light and fragile body, though, and therefore offer inadequate safety protection. TheInsurance Institute for Highway Safety in America had condemned the use of low speed vehicles and "mini trucks," referred to as neighborhood electric vehicles (NEVs) when powered by electric motors, on public roads(HP Pavilion DV6-1210SA battery).

Hazard to pedestrians

At low speeds, electric cars produced less roadway noise as compared to vehicles propelled by a internal combustion engine. Blind people or the visually impairedconsider the noise of combustion engines a helpful aid while crossing streets, hence electric cars and hybrids could pose an unexpected hazard(SONY VGP-BPS11 battery). Tests have shown that this is a valid concern, as vehicles operating in electric mode can be particularly hard to hear below 20 mph (30 km/h) for all types of road users and not only the visually impaired. At higher speeds the sound created by tire friction and the air displaced by the vehicle start to make sufficient audible noise(SONY VGP-BPL11 battery).

The US Congress and the Government of Japan passed legislation to regulate the minimum level of sound for hybrids and plug-in electric vehicleswhen operating in electric mode, so that blind people and other pedestrians and cyclists can hear them coming and detect from which direction they are approaching(SONY VGP-BPL12 battery). The Nissan Leaf is the first electric car to use Nissan's Vehicle Sound for Pedestrians system, which includes one sound for forward motion and another for reverse.

Differences in controls

Presently most EV manufacturers do their best to emulate the driving experience as closely as possible to that of a car with a conventional automatic transmission that motorists are familiar with(SONY VGP-BPS12 battery). Most models therefore have a PRNDL selector traditionally found in cars with automatic transmission despite the underlaying mechanical differences. Push buttons are the easiest to implement as all modes are implemented through software on the vehicle's controller(SONY VGP-BPS14 Battery).

Even though the motor may be permanently connected to the wheels through a fixed-ratio gear and no parking pawl may be present the modes "P" and "N" will still be provided on the selector. In this case the motor is disabled in "N" and an electrically actuated handbrake provides the "P" mode(SONY VGP-BPS14/B Battery).

In some cars the motor will spin slowly to provide a small amount of creep in "D", similar to a traditional automatic.

When the foot is lifted from the accelerator of an ICE, engine braking causes the car to slow. An EV would coast under these conditions, and applying mild regenerative braking instead provides a more familiar response(SONY VGP-BPS14/S Battery). Selecting the L mode will increase this effect for sustained downhill driving, analogous to selecting a lower gear.

Cabin heating and cooling

Electric vehicles generate very little waste heat and resistance electric heat may have to be used to heat the interior of the vehicle if heat generated from battery charging/discharging can not be used to heat the interior(SONY VGP-BPS14B Battery).

While heating can be simply provided with an electric resistance heater, higher efficiency and integral cooling can be obtained with a reversible heat pump (this is currently implemented in the hybrid Toyota Prius).Positive Temperature Coefficient (PTC) junction cooling is also attractive for its simplicity - this kind of system is used for example in the Tesla Roadster(SONY VGP-BPS22 battery).

Some electric cars, for example the Citroën Berlingo Electrique, use an auxiliary heating system (for example gasoline-fueled units manufactured by Webasto or Eberspächer) but sacrifice "green" and "Zero emissions" credentials. Cabin cooling can be augmented with solar power(SONY VGP-BPS18 battery), most simply and effectively by inducting outside air to avoid extreme heat buildup when the vehicle is closed and parked in the sunlight (such cooling mechanisms are available as aftermarket kits for conventional vehicles). Two models of the 2010 Toyota Prius include this feature as an option(SONY VGP-BPS22/A battery).

Batteries

Finding the economic balance of range against performance, energy density, and accumulator type versus cost challenges every EV manufacturer.

While most current highway-speed electric vehicle designs focus on lithium-ion and other lithium-based variants a variety of alternative batteries can also be used(SONY VGP-BPS22A battery). Lithium based batteries are often chosen for their high power and energy density but have a limited shelf-life and cycle lifetime which can significantly increase the running costs of the vehicle. Variants such as Lithium iron phosphate and Lithium-titanate attempt to solve the durability issues with traditional lithium-ion batteries(SONY VGP-BPL10 battery).

Other battery technologies include:

Lead acid batteries are still the most used form of power for most of the electric vehicles used today. The initial construction costs are significantly lower than for other battery types, and while power output to weight is poorer than other designs, range and power can be easily added by increasing the number of batteries(SONY VGP-BPS10 battery).

NiCd - Largely superseded by NiMH

Nickel metal hydride (NiMH)

Nickel iron battery - Known for its comparatively long lifetime and low power density

Several battery technologies are also in development such as(Dell Latitude E6500 battery):

Zinc-air battery

Molten salt battery

Zinc-bromine flow batteries or Vanadium redox batteries can be refilled, instead of recharged, saving time. The depleted electrolyte can be recharged at the point of exchange, or taken away to a remote station(Dell Latitude E6400 battery).

Travel range before recharging

The range of an electric car depends on the number and type of batteries used. The weight and type of vehicle, and the performance demands of the driver, also have an impact just as they do on the range oftraditional vehicles. The range of an electric vehicle conversion depends on the battery type(Dell Latitude E5400 battery):

Replacing

An alternative to quick recharging is to exchange the drained or nearly drained batteries (or battery range extender modules) with fully charged batteries, rather asstagecoach horses were changed at coaching inns. Batteries could be leased or rented instead of bought, and then maintenance deferred to the leasing or rental company, and ensures availability(SONY Vaio VGN-FW31J Battery).

Renault announced at the 2009 Frankfurt Motor Show that they have sponsored a network of charging stations and plug-in plug-out battery swap stations. Other vehicle manufacturers and companies are also investigating the possibility(SONY Vaio VGN-FW32J Battery).

Replaceable batteries were used in the electric buses at the 2008 Summer Olympics.

Vehicle-to-grid: uploading and grid buffering

A Smart grid allows BEVs to provide power to the grid, specifically:

During peak load periods, when the cost of electricity can be very high(SONY Vaio VGN-FW17W Battery). These vehicles can then be recharged during off-peak hours at cheaper rates while helping to absorb excess night time generation. Here the batteries in the vehicles serve as a distributed storage system to buffer power.

During blackouts, as an emergency backup supply(SONY Vaio VGN-FW31E Battery).

Such a system will not be widely feasible until the cycle durability of battery packs is significantly increased.

Lifespan

Battery life should be considered when calculating the extended cost of ownership, as all batteries eventually wear out and must be replaced. The rate at which they expire depends on the type of battery technology and how they are used - many types of batteries are damaged by depleting them beyond a certain level. Lithium-ion batteries degrade faster when stored at higher temperatures(SONY Vaio VGN-FW139E Battery).

Future

The future of battery electric vehicles depends primarily upon the cost and availability of batteries with high specific energy, power density, and long life, as all other aspects such as motors, motor controllers, and chargers are fairly mature and cost-competitive with internal combustion engine components(SONY Vaio VGN-FW139E/H Battery). Diarmuid O'Connell, VP of Business Development at Tesla Motors, estimates that by the year 2020 30% of the cars driving on the road will be battery, electric or plug-in hybrid.

Nissan CEO Carlos Ghosn has predicted that one in 10 cars globally will run on battery power alone by 2020(SONY Vaio VGN-FW31M Battery). Additionally a recent report claims that by 2020 electric cars and other green cars will take a third of the total of global car sales.

It is estimated that there are sufficient lithium reserves to power 4 billion electric cars.

Other methods of energy storage

Experimental supercapacitors and flywheel energy storage devices offer comparable storage capacity, faster charging, and lower volatility(SONY VAIO VGN-FZ21E Battery). They have the potential to overtake batteries as the preferred rechargeable storage for EVs. The FIA included their use in its sporting regulations of energy systems for Formula One race vehicles in 2007 (for supercapacitors) and 2009 (for flywheel energy storage devices) (SONY VAIO VGN-FZ21Z Battery).

Solar cars

Solar cars are electric cars that derive most or all of their electricity from built in solar panels. After the 2005 World Solar Challenge established that solar race cars could exceed highway speeds, the specifications were changed to provide for vehicles that with little modification could be used for transportation(SONY VAIO VGN-FZ21J Battery).

Charging

Batteries in BEVs must be periodically recharged (see also Replacing, above).

Unlike vehicles powered by fossil fuels, BEVs are most commonly and conveniently charged from the power grid overnight at home, without the inconvenience of having to go to a filling station(SONY Vaio VGN-FW11 Battery). Charging can also be done using a street or shop charging station.

The electricity on the grid is in turn generated from a variety of sources; such as coal, hydroelectricity, nuclear and others. Power sources such as roof top photovoltaicsolar cell panels, micro hydro or wind may also be used and are promoted because of concerns regarding global warming(SONY Vaio VGN-FW11M Battery).

Level 1, 2, and 3 charging

Around 1998 the California Air Resources Board classified levels of charging power that have been codified in title 13 of the California Code of Regulations, the U.S. 1999National Electrical Code section 625 and SAE International standards(SONY Vaio VGN-FW11S Battery).

More recently the term "Level 3" has also been used by the SAE J1772 Standard Committee for a possible future higher-power AC fast charging standard. To distinguish from Level 3 DC fast charging, this would-be standard is written as "Level 3 AC". SAE has not yet approved standards for either AC or DC Level 3 charging(SONY Vaio VGN-FW21E Battery).

For comparison in Europe the IEC 61851-1 charging modes are used to classify charging equipment. The provisions of IEC 62196 charging modesfor conductive charging of electric vehicles include Mode 1 (max. 16A / max. 250V a.c. or 480V three-phase), Mode 2 (max. 32A / max. 250V a.c. or 480V three-phase) (SONY Vaio VGN-FW21J Battery), Mode 3 (max. 250A / max. 690V a.c. or three-phase) and Mode 4 (max. 400A / max. 600V d.c.).

Connectors

Most electric cars have used conductive coupling to supply electricity for recharging after the California Air Resources Board settled on the SAE J1772-2001 standard as the charging interface for electric vehicles in California in June 2001(SONY Vaio VGN-FW21L Battery). In Europe the ACEA has decided to use the Type 2 connector from the range of IEC_62196 plug types for conductive charging of electric vehicles in the European Union as the Type 1 connector (SAE J1772-2009) does not provide for three-phase charging(SONY Vaio VGN-FW21M Battery).

Another approach is inductive charging using a non-conducting "paddle" inserted into a slot in the car. Delco Electronics developed the Magne Charge inductive charging system around 1998 for the General Motors EV1 and it was also used for the Chevrolet S-10 EV and Toyota RAV4 EVvehicles(SONY VGP-BPS13Q Battery).

Regenerative braking

Using regenerative braking, a feature which is present on many hybrid electric vehicles, approximately 20% of the energy usually lost in the brakes is recovered to recharge the batteries(SONY VGP-BPS13B/Q Battery).

Charging time

More electrical power to the car reduces charging time. Power is limited by the capacity of the grid connection, and, for level 1 and 2 charging, by the power rating of the car's on-board charger. A normal householdoutlet is between 1.5 kW (SONY VGN NR11S/S battery) (in the US, Canada, Japan, and other countries with 110 volt supply) to 3 kW (in countries with 230V supply). The main connection to a house may sustain 10, 15 or even 20 kW in addition to "normal" domestic loads - though it would be unwise to use all the apparent capability - and special wiring can be installed to use this(SONY VGN NR11M/S battery). As examples of on-board chargers, the Nissan Leaf at launch has a 3.3 kW charger and the Tesla Roadster appears to accept 16.8 kW (240V at 70A) from the Tesla Home Connector. These power numbers are small compared to the effective power delivery rate of an average petrol pump, about 5,000 kW(SONY VGN NR11Z/S battery). Even if the electrical supply power can be increased, most batteries do not accept charge at greater than their charge rate ("1C"), because high charge rates have an adverse effect on the discharge capacities of batteries(SONY VGN NR11Z/T battery). Despite these power limitations, plugging in to even the least-powerful conventional home outlet provides more than 15 kilowatt-hours of energy overnight, sufficient to propel most electric cars more than 70 kilometres (43 mi) (see Energy efficiency above) (SONY VGP-BPS13A/Q Battery).

Faster charging

Some types of batteries such as Lithium-titanate, LiFePO4 and even certain NiMH variants can be charged almost to their full capacity in 10–20 minutes. Fast charging requires very high currents often derived from a three-phase power supply. Careful charge management is required to prevent damage to the batteries through overcharging(SONY VGP-BPS21/S Battery).

Most people do not usually require fast recharging because they have enough time, six to eight hours (depending on discharge level) during the work day or overnight at home to recharge. BEV drivers frequently prefer recharging at home, avoiding the inconvenience of visiting a public charging station(SONY VGP-BPS21 Battery).

Hobbyists, conversions, and racing

Hobbyists often build their own EVs by converting existing production cars to run solely on electricity. There is a cottage industry supporting the conversion and construction of BEVs by hobbyists. Universities such as the University of California, Irvine even build their own custom electric or hybrid-electric cars from scratch(SONY VGP-BPS21B Battery).

Short-range battery electric vehicles can offer the hobbyist comfort, utility, and quickness, sacrificing only range. Short-range EVs may be built using high-performance lead–acid batteries, using about half the mass needed for a 100 to 130 km (60 to 80 mi) range. The result is a vehicle with about a 50 km (30 mi) range(SONY VGP-BPS21A/B Battery), which, when designed with appropriate weight distribution (40/60 front to rear), does not require power steering, offers exceptional acceleration in the lower end of its operating range, and is freeway capable and legal(SONY VAIO PCG-5K1L battery). But their EVs are expensive due to the higher cost for these higher-performance batteries. By including a manual transmission, short-range EVs can obtain both better performance and greater efficiency than the single-speed EVs developed by major manufacturers(SONY VGP-BPS13B/S Battery). Unlike the converted golf carts used forneighborhood electric vehicles, short-range EVs may be operated on typical suburban throughways (where 60–80 km/h / 35-50 mph speed limits are typical) and can keep up with traffic typical on such roads and the short "slow-lane" on-and-off segments of freeways common in suburban areas(SONY VGP-BPS13S Battery).

Faced with chronic fuel shortage on the Gaza Strip, Palestinian electrical engineer Waseem Othman al-Khozendar invented in 2008 a way to convert his car to run on 32 electric batteries. According to al-Khozendar, the batteries can be charged with US$2 worth of electricity to drive from 180 to 240 km (110 to 150 mi) (SONY VGP-BPS13A/S Battery). After a 7-hour charge, the car should also be able to run up to a speed of 100 km/h (60 mph).

Japanese Professor Hiroshi Shimizu from Faculty of Environmental Information of the Keio University created an electric limousine: the Eliica(Electric Lithium-Ion Car) has eight wheels with electric 55 kW hub motors (8WD) with an output of 470 kW and zero emissions(Sony VAIO VGN-FZ15G Battery), a top speed of 370 km/h (230 mph), and a maximum range of 320 km (200 mi) provided by lithium-ion batteries. However, current models cost approximately US$300,000, about one third of which is the cost of the batteries.

In 2008, several Chinese manufacturers began marketing lithium iron phosphate (LiFePO4) batteries directly to hobbyists and vehicle conversion shops(Dell INSPIRON 1764 battery). These batteries offered much better power to weight ratios allowing vehicle conversions to typically achieve 75 to 150 mi (120 to 240 km) per charge. Prices gradually declined to approximately US$350 per kW·h by mid 2009. As the LiFePO4 cells feature life ratings of 3,000 cycles(Dell INSPIRON 1564 battery), compared to typical lead acid battery ratings of 300 cycles, the life expectancy of LiFePO4 cells is around 10 years. This has led to a resurgence in the number of vehicles converted by individuals. LiFePO4cells do require more expensive battery management and charging systems than lead acid batteries(Dell INSPIRON 1464 battery).

Electric drag racing is a sport where electric vehicles start from standstill and attempt the highest possible speed over a short given distance. Organizations such asNEDRA keep track of records world wide using certified equipment(Dell INSPIRON 1520 battery).