An electric vehicle, or EV, is a vehicle with one or more electric motors for propulsion. This is also referred to as an electric drive vehicle. The motion may be provided either by wheels or propellers driven by rotary motors, or in the case of tracked vehicles, by linear motors.
Unlike an internal combustion engine that is tuned to specifically operate with a particular fuel such as gasoline or diesel, an electric drive vehicle needs electricity, which comes from sources such as batteries, fuel cells or a generator. This flexibility allows the drive train of the vehicle to remain the same, while the fuel source can be changed.
The energy used to propel the vehicle may be obtained from several sources, some of them more ecological than others:
It is also possible to have hybrid electric vehicles that derives energy from multiple sources. Such as:
Electric vehicles can include electric airplanes, electric boats, and electric motorcycles and scooters.
Electric motive power started with a small railway operated by a miniature electric motor, built by Thomas Davenport in 1835. In 1838, a Scotsman named Robert Davidson built an electric locomotive that attained a speed of four miles an hour. In England a patent was granted in 1840 for the use of rails as conductors of electric current, and similar American patents were issued to Lilley and Colten in 1847.
Between 1832 and 1839 (the exact year is uncertain), Robert Anderson of Scotland invented the first crude electric carriage, powered by non-rechargeable Primary cells.
By the 20th century, electric cars and rail transport were commonplace, with commercial electric automobiles having the majority of the market. Over time their general-purpose commercial use reduced to specialist roles, as platform trucks, forklift trucks, tow tractors and urban delivery vehicles, such as the iconic British milk float; for most of the 20th century, the UK was the world's largest user of electric road vehicles.
Electrified trains were used for coal transport as the motors did not use precious oxygen in the mines. Switzerland's lack of natural fossil resources forced the rapid electrification of their rail network. One of the earliest rechargeable batteries - the Nickel-iron battery - was favored by Edison for use in electric cars.
Electric vehicles were among the earliest automobiles, and before the preeminence of light, powerful internal combustion engines, electric automobiles held many vehicle land speed and distance records in the early 1900s. They were produced by Baker Electric, Columbia Electric, Detroit Electric, and others and at one point in history out-sold gasoline-powered vehicles.
In the 1930s, National City Lines, which was a partnership of General Motors, Firestone, and Standard Oil of California purchased many electric tram networks across the country to dismantle them and replace them with GM buses. The partnership was convicted of conspiring to monopolize the sale of equipment and supplies to their subsidiary companies conspiracy, but were acquitted of conspiring to monopolize the provision of transportation services. Electric tram line technologies could be used to recharge BEVs and PHEVs on the highway while the user drives, providing virtually unrestricted driving range. The technology is old and well established (see : Conduit current collection, Nickel-iron battery). The infrastructure has not been built.
In January 1990, General Motors' President introduced its EV concept two-seater, the "Impact," at the Los Angeles Auto Show. That September, the California Air Resources Board mandated major-automaker sales of EVs, in phases starting in 1998. From 1996 to 1998 GM produced 1117 EV1s, 800 of which were made available through 3-year leases.
Chrysler, Ford, GM, Honda, Nissan and Toyota also produced limited numbers of EVs for California drivers. In 2003, upon the expiration of EV1 leases, GM crushed them. The crushing has variously been attributed to 1) the auto industry's successful Federal Court challenge to California's Zero-emissions vehicle mandate, 2) a federal regulation requiring GM to produce and maintain spare parts for the few thousands EV1s and 3) the success of the Oil and Auto industries' media campaign to reduce public acceptance of electric vehicles.
A movie made on the subject in 2005-2006 was titled Who Killed the Electric Car? and released theatrically by Sony Pictures Classics in 2006. The film explores the roles of automobile manufacturers, oil industry, the US government, batteries, hydrogen vehicles, and consumers, and each of their roles in limiting the deployment and adoption of this technology.
Honda, Nissan and Toyota also repossessed and crushed most of their EVs, which, like the GM EV1s, had been available only by closed-end lease. After public protests, Toyota sold 200 of its RAV EVs to eager buyers; they now sell, five years later, at over their original forty-thousand-dollar price.
In 2008, Mitsubishi Motors and PSA Peugeot Citroen are going to collaborate in technology for electric vehicles as the global race to build green cars heats up.
(See articles on diesel-electric and gasoline-electric hybrid locomotion for information on electric vehicles using internal-combustion energy sources).
Batteries, electric double-layer capacitors and flywheel energy storage are forms of rechargeable on-board electrical storage. By avoiding an intermediate mechanical step, the energy conversion efficiency can be improved over the hybrids already discussed, by avoiding unnecessary energy conversions. Furthermore, electro-chemical batteries conversions are easy to reverse, allowing electrical energy to be stored in chemical form.
Another form of chemical to electrical conversion is fuel cells, projected for future use.
For especially large electric vehicles, such as submarines, the chemical energy of the diesel-electric can be replaced by a nuclear reactor. The nuclear reactor usually provides heat, which drives a steam turbine, which drives a generator, which is then fed to the propulsion. See Nuclear Power
Most large electric transport systems are powered by stationary sources of electricity that are directly connected to the vehicles through wires. Due to the extra infrastructure and difficulty in handling arbitrary travel, most directly connected vehicles are owned publicly or by large companies. These forms of transportation are covered in more detail in metros, trams, electric locomotives, and trolleybuses.
In the systems above motion is provided by a rotary electric motor. However, it is possible to "unroll" the motor to drive directly against a special matched track. These linear motors are used in maglev trains which float above the rails supported by magnetic levitation. This allows for almost no rolling resistance of the vehicle and no mechanical wear and tear of the train or track. Levitation and forward motion are two independent effects; the forward motive force normally requires external power, although some types, such as Inductrack, achieve levitation at low speeds without any. In addition to the high-performance control systems needed, switching and curving of the tracks becomes difficult with linear motors, which to date has restricted their operations to high-speed point to point services.
Some bicycles have been converted to electric power with a small battery and a small electric motor, some even have solar panels that are folded out when the vehicle is at rest. Small scale electric vehicles include electric cars, light trucks, neighborhood electric vehicles, motorcycles, motorized bicycles, electric scooters , golf carts, milk floats, forklifts and similar vehicles.
Although electric vehicles have few direct emissions, all rely on energy created through electricity generation which will emit pollution and generate waste, unless it is generated by renewable source power plants. Even with power plants emitting CO2, the overall levels would be reduced because the entire process of moving a car is more efficient using electricity than producing gasoline and burning it in a car's engine. Since electric vehicles use whatever electricity is delivered by their electrical utility/grid operator, it is effortless to make vast amounts of electric vehicles more efficient or reduce/eliminate pollution by modify their generation stations that are the electrical source for them. This would be done by an electrical utility or by the government under an energy policy.
Fossil fuel vehicle efficiency and pollution standards take years or decades to take effect over a majority nation's vehicle fleet, since those new efficiency and pollution standards can propagate through retirement, scrapping, and totalling of vehicles already on the road. To upgrade or change the energy source of all only-fossil fuel vehicles already on the road or apply new pollution or efficiency standards to them at once, would be impossible in most societies, because of unaffordability by the vehicles' owners or upgrade costs exceed vehicle costs, owner possessiveness and social upheaval. In democracies, the populace and/or elected officials would terminate such a plan, in non-democratic nations, a military response would be required to enforce such upgrade regulations leading to instability which could result in a loss of power against the current regime. In nations with fixed cutoffs of retirement of old vehicles such as Japan or Singapore a mandatory upgrade of all vehicles already on the road, or in nations without a lower or middle class owning vehicles or the nations where such would be illegal (which leaves only large business and/or government and/or the upper class owning fossil fuel vehicles), would be more feasible to mass upgrades of fossil fuel vehicles already on the road.
Naturally, electric vehicles will take advantage of whatever environmental gains happen when a renewable energy generation station comes online, a fossil fuel station is decommissioned or upgraded. There is a con to this, if a government or economic conditions or an electrical utility decides to run a region's electrical grid off more polluting fossil fuels, or more inefficiently, the reverse can happen. Even in such a situation, electrical vehicles are still more efficient than a comparable amount of fossil fuel vehicles. In areas with a deregulated electrical energy market, an electrical vehicle owner can choose whether to run his electrical vehicle off conventional electrical energy sources, or strictly from renewable electrical energy sources (presumably at an additional cost), and switch at any time between the two.
If a large proportion of private vehicles were to convert to grid electricity, the existing power plant and transmission infrastructure would be nearly sufficient, assuming most charging occurred overnight using the most efficient off-peak base load sources. But there would be a significant need for additional resources (and emissions) in generation. However, the overall energy consumption would diminish because of the higher efficiency of electric vehicles over the entire cycle.
Electromagnetic radiation from high performance electrical motors has been claimed to be associated with some human ailments, but such claims are largely unsubstantiated except for extremely high exposures. Electric motors can be shielded within a metallic Faraday's cage, but this adds weight to the vehicle and it is not conclusive that all electromagnetic radiation can be contained.
On an energy basis, the price of electricity to run an EV is a small fraction of the cost of liquid fuel needed to produce an equivalent amount of energy. Issues related to batteries, however, can add to the operating costs.
Traditionally, most EVs have used lead-acid batteries due to their mature technology, high availability, and low cost (exception: some early EVs, such as the Detroit Electric, used nickel-iron.) Like all batteries, these have an environmental impact through their construction, use, disposal or recycling. On the upside, vehicle battery recycling rates top 95% in the United States. Deep-cycle lead batteries are expensive and have a shorter life than the vehicle itself, typically needing replacement every 3 years.
Lead-acid batteries in EV applications end up being a significant (25%-50%) portion of the final vehicle mass. Like all batteries, they have significantly lower energy density than petroleum fuels -- in this case, 30-40Wh/kg. While the difference isn't as extreme as it first appears due to the lighter drive-train in an EV, even the best batteries tend to lead to higher masses when applied to vehicles with a normal range. The efficiency and storage capacity of the current generation of common deep cycle lead acid batteries decreases with lower temperatures, and diverting power to run a heating coil reduces efficiency and range by up to 40%. Recent advances in battery efficiency, capacity, materials, safety, toxicity and durability are likely to allow these superior characteristics to be applied in car-sized EVs.
Charging and operation of batteries typically results in the emission of hydrogen, oxygen and sulfur, which are naturally occurring and normally harmless if properly vented. Early Citicar owners discovered that, if not vented properly, unpleasant sulfur smells would leak into the cabin immediately after charging.
Lead-acid batteries have been re-engineered by Firefly Energy, increasing longevity, slightly increasing energy density, and significantly increasing power density. Firefly is expected market lightweight vehicle batteries, either directly or through manufacturing partners in 2008.
Lead-acid batteries powered such early-modern EVs as the original versions of the EV1 and the RAV4EV.
Nickel-metal hydride batteries are now considered a relatively mature technology. While less efficient in charging and discharging than even lead-acid, they boast an energy density of 30-80Wh/kg, far higher than lead-acid. When used properly, nickel-metal hydride batteries can have exceptionally long lives, as has been demonstrated in their use in hybrid cars and surviving NiMH RAV4EVs that still operate well after 100,000 miles and over a decade of service. Downsides include the poor efficiency, high self-discharge, very finicky charge cycles, and poor performance in cold weather. GM Ovonic produced the NiMH battery used in the second generation EV-1, and Cobasys makes a nearly identical battery (ten 1.2V 85Ah NiMH cells in series in contrast with eleven cells for Ovonic battery). This worked very well in the Saturn EV-1. It remains a viable and practical solution today, as far as a superior alternative to the lead acid battery. However, for non-technical reasons neither company will provide their NiMH battery for automotive applications - a policy strictly enforced. Moreover, GM now owns patent(s) on some proprietary technology and processes used to manufacture this type of battery. Therefore no other company can produce a similar battery (with capacities large enough for electric vehicle propulsion) without infringing GM's patents. So, despite its technical success, unless GM will change their position on the issue NiMH traction battery technology, it is considered a dead end. In light of the latest developments in lithium based battery technology and patent issues of NiMH, lithium will most likely represent the future EV battery type.
The sodium or "zebra" battery uses a molten chloroaluminate (NaAlCl4) salt as the electrolyte. Also a relatively mature technology, the Zebra battery boasts a good energy density of 90Wh/kg and near lossless charge/discharge cycles. Since the battery must be heated for use, cold weather doesn't strongly affect its operation except for in increasing heating costs. It has been used in several EVs. The downsides to the Zebra battery include poor power density and the requirement of having to heat the electrolyte, which wastes energy and presents difficulties in long-term storage of charge. Zebras can last for a few thousand charge cycles and are nontoxic.
Lithium-ion (and similar lithium polymer) batteries, widely known through their use in laptops and consumer electronics, dominate the most recent group of EVs in development. The traditional lithium-ion chemistry involves a lithium cobalt oxide cathode and a graphite anode. This yields cells with an impressive 160Wh/kg energy density and good power density, and near lossless charge/discharge cycles. The downsides of traditional lithium-ion batteries include short cycle lifes (hundreds to a few thousand charge cycles) and significant degradation with age. The cathode is also somewhat toxic. Also, traditional lithium-ion batteries can pose a fire safety risk if punctured or charged improperly. The maturity of this technology is moderate. The Tesla Roadster uses "blades" of traditional lithium-ion "laptop battery" cells that can be replaced individually as needed.
Most other EVs are utilizing new variations on lithium-ion chemistry that sacrifice energy density (often resulting in batteries with 100Wh/kg or less) to provide extreme power density, fire resistance, environmental friendliness, very rapid charges (as low as a few minutes), and very long lifespans. These variants (phosphates, titanates, spinels, etc) have been shown to have a much longer lifetime, with A123 expecting their lithium iron phosphate batteries to last for at least 10+ years and 7000+ charge cycles, and LG Chem expecting their lithium-manganese spinel batteries to last up to 40 years.
Much work is being done on lithium ion batteries in the lab. Lithium vanadium oxide has already made its way into the Subaru prototype G4e, doubling energy density. Silicon nanowires, silicon nanoparticles, and tin nanoparticles promise several times the energy density in the anode, while composite and superlattice cathodes also promise significant density improvements.
Assuming a 50 kilowatt-hour battery pack and ideal charging efficiency, a ten minute quick charge from 10% to 80% capacity would require a power draw of 210 kilowatts from the electric grid. At 240 Volts, this means a current draw of 875 Amperes from the outlet. In practice, the energy efficiency of quick charging is likely to be somewhat lowered due to the ohmic losses caused by the required high current. The lost energy is converted directly to heat, which causes wear to the battery pack and other electronics involved. Increasing the capacity of the battery pack increases the required power, current and heat loss linearly, which is why quick charging may become impractical or impossible as vehicles with increased range are developed.
The high peak power requirement of quick charging also puts additional stress to the local power grid and may put it to a risk of failure during periods of peak demand. The most obvious solution is to use another battery to act as a buffer between the charging station and the power grid. The battery as a buffer however, suffers a similar efficiency drop as the car itself, thus lowering the overall efficiency of the system. Another possibility is on-site, on-demand electricity generation.
Battery replacement is also proposed as an alternative. While it suffers from some problems (weight, standardization, etc), Project Better Place has already raised several hundred million dollars to build networks of charging and battery replacement stations. One type of battery "replacement" proposed is much simpler: while the latest generation of vanadium redox battery only has an energy density similar to lead-acid, the charge is stored solely in a vanadium-based electrolyte, which can be pumped out and replaced with charged fluid.
Conventional electric double-layer capacitors are being worked to achieve the energy density of lithium ion batteries, offering almost unlimited lifespans and no environmental issues. High-K electric double-layer capacitors, such as EEStor's EESU, promise to best lithium ion energy density several times over if they can be produced. Lithium-sulphur batteries offer 250Wh/kg. Sodium-ion batteries promise 400Wh/kg with only minimal expansion/contraction during charge/discharge and a very high surface area.
Electric motors often achieve 90% energy conversion efficiencyover the full range of speeds and power output and can be precisely controlled. They can also be combined with regenerative braking systems that have the ability to convert movement energy back into stored electricity. This can be used to reduce the wear on brake systems (and consequent brake pad dust) and reduce the total energy requirement of a trip, especially effective for start-and-stop city use.
They can be finely controlled and provide high torque from rest, unlike internal combustion engines, and do not need multiple gears to match power curves. This removes the need for gearboxes and torque converters.
Another advantage is that electric vehicles typically have less vibration and noise pollution than a vehicle powered by an internal combustion engine, whether it is at rest or in motion.
Electricity is a form of energy that remains within the continent where it was produced and can be multi-sourced. As a result it gives the greatest degree of energy resilience .
The GM Volt will cost "less than purchasing a cup of your favorite coffee" to recharge. The Volt should cost less than 2 cents per mile to drive on electricity, compared with 12 cents a mile on gasoline at a price of $3.60 a gallon. This would be the equillant to paying 70 cents a gallon of gas.
Long recharge times compared to the refueling time required by internal combustion engined vehicles.
Most electricity generation in the United States, is from fossil sources, according to the US DOE.
The US national grid is under invested and is having trouble meeting current levels of demand according to the US DOE.
Overall average efficiency from US power plants (33% efficient) to point of use (transmission loss 9.5%), (US DOE figures) is 29.87% . Accepting 90% efficiency for the electric vehicle gives us a figure of only 26.88% overall efficiency. That is lower than internal combustion engined vehicles (Petrol/Gasoline 30% efficient, Diesel engines 45% efficient - Volvo figures). Diesel engines can also easily run on renewable fuels, biodiesel, vegetable oil fuel (preferably from waste sources), with no loss of efficiency. Using grid electricity entirely negates the efficiency advantages of electric vehicles.
This comparison isn't entirely fair, though, since it compares tank-to-flywheel efficiency of gasoline and diesel powered engines to the well-to-wheel efficiency of electric motors. It also fails to recognize that the practical efficiency of the internal combustion engine is significantly lower in actual use, because of transmission and idling losses. Idling losses were addressed by VW in the 1980s with its 'Formel E' technology, that has been updated as 'Blue Motion'. Reference/Info to follow for transmission losses.
To achieve a sound conclusion, one would also have to take into account the refining and delivery losses of gasoline and diesel, and the energy efficiency of biofuel production. (Output fuel energy divided by the sum of the invested energy and energy in the biomass). The equivalent for fossil electricity production would also need to be considered (mining and transportation of coal to the power station for example, or the Co2 produced building renewable electricity generation).
AVERE has a table summarizing the taxation and incentives for these vehicles in the different European countries, related to state subsidies, reduction of VAT and other taxes, insurance facilities, parking and charging facilities (including free recharging on street or in the parking ares), EV imposed by law and banned circulation for petroleum cars, permission to use bus lanes, free road tax, toll free on highways and exempt from congestion charging free or reduced parking, free charging at charge points, between others . In Denmark petrol cars is taxed 180%+25% however EV cars (max. 2000 kg total weight) is only taxed 25%, free parking in Copenhagen and other cities, free recharging at some parking spaces.
Practically the only EV to have been manufactured for several years is the Indian REVA. It is produced by REVA Electric Car Company Private Ltd. (RECC) in Bangalore, India, a company established in 1994 as a joint venture between the Maini Group India and AEV LLC, California USA. After seven years of R&D, they commercialized the first REVA car in June 2001.
The current version of the REVA is the REVAi. It was first reserved for the Indian market, but it is now distributed in several European countries: UK (by GoinGreen under the name G-Wiz), Cyprus and Greece (by REVA Phaedra Electricity Mobility Ltd., Belgium (by Green Mobil), Norway (by Ole Chr. Bye AS), Spain (by Emovement)and Germany (by Elektro PKW). It may be exported to the USA with a speed limiter for use as a Neighborhood Electric Vehicle (NEV).
Most of the EVs that Chrysler, Ford, GM (EV1), Honda, Nissan and Toyota produced in limited numbers for California drivers were crushed.
The production of the Citroën Berlingo Electrique stopped in September 2005.
Several Industry giants, such as Daimler AG, Toyota Motor Corp., General Motors Corp., Renault SA and Mitsubishi Corp., are developing new-generation electric vehicles.
Myers Motors, a small private company, has created an electric personal Three wheeled car called NMG (No More Gas). This car can take only one passenger, and is being sold in very small numbers in the US only.
With Tata, Ajanta and Tara talking about 'low-cost' cars and "less than a Tata Nano".
Several start-up companies like Tesla Motors, Ronaele Incorporated, Commuter Cars, Phoenix Motorcars, Miles Electric Vehicles, and Aptera Motors will have powerful battery-electric vehicles available to the public in 2008. Battery and energy storage technology is advancing rapidly. The average distance driven by 80% of citizens per day in a car in the US is about 50 miles (US dept of transport, 1991), which fits easily within the current range of the electric car. This range can be improved by technologies such as Plug-in hybrid electric vehicles which are capable of using traditional fuels for unlimited range, rapid charging stations for BEVs, improved energy density batteries, flow batteries, or battery swapping.
In 2006 GM began the development of a plug-in hybrid that will use a lithium-ion battery. The vehicle, initially known as the iCar, is now called the Chevrolet Volt. The basic design was first exhibited January 2007 at the North American International Auto Show. GM is planning to have this EV ready for sale to the public in the latter half of 2010. The car is to have a 50 mile range. If the battery capacity falls below 30 percent a small internal combustion engine will kick in to charge the battery on the go. This in effect increases the range of the vehicle, allowing it to be driven until it can be fully charged by plugging it into a standard household AC electrical source.
On October 29, 2007, Shai Agassi launched Project Better Place, a company focused on building massive scale Electric Recharge Grids as infrastructure supporting the deployment of electric vehicles (including plug-in hybrids) in countries around the world. On January 21, BPP and the Nissan-Renault group signed a MOU - PBP will provide the battery recharging and swapping infrastructure and Renault-Nissan will mass-produce the vehicles.
