by Bill Siuru
Later this year, manufacturers will begin delivering plug-in electric vehicles (PEVs). In the U.S., these include battery electric vehicles (BEVs) such as the Nissan Leaf and Mitsubishi i MiEV; extended-range electric vehicles such as the Chevrolet Volt; and plug-in hybrid electric vehicles (PHEVs) such as the Toyota Prius PHEV.
These will be followed by the BMW Megacity, Ford Focus EV, Chrysler-Fiat 500EV, smart EV and others. Smaller manufacturers such as Tesla Motors, Fisker Automotive, Mahindra Reva Electric Vehicle Co. and Think also will compete in this growing and potentially large market.
The 2011 Chevrolet Volt is an extended-range electric vehicle that can travel up to 40 miles on a fully charged battery and more than 600 miles when the gasoline engine-driven generator supplies electricity to drive the wheels and recharge the battery. Courtesy of Chevrolet
They all need to plug in somewhere. Consumers can use home charging systems for overnight battery charging. Charging stations will be installed at apartment complexes, office buildings, parking lots, shopping malls, restaurants and existing filling stations. The charging infrastructure for PEVs is a much smaller challenge than creating the distribution infrastructure for other alternative fuels, such as hydrogen for fuel cell vehicles. More than half of U.S. homes already have the capability to charge PEVs, but some modifications for charging batteries at the more desirable, higher charge rates might be required. KB Home, one of the nation's largest homebuilders operating in 10 states, is the first to offer homes pre-wired for electric car charging.
The Volt will come with two SAE J1772-compliant chargers: a wall-mounted, 240-volt, fast-charge unit that can fully charge in about three hours; and a portable, 120-volt charge cord to charge the Volt in about eight hours. Courtesy of Chevrolet
BEVs can be refueled only at charging points, but owners of extended range electric vehicles (EREVs) and PHEVs will want to plug in to minimize fuel consumption and emissions. For example, Volt drivers who drive fewer than about 40 miles daily can do all charging at home and never have to visit a filling station.
Electric cars were popular before Charles Kettering invented a successful electric starter first used in 1912 Cadillacs. For the next 100 years, interest was sporadic mainly because of battery limitations, namely limited driving range, high cost and long recharge times.
Today’s advanced battery chemistries such as lithium-ion provide about a 100-mile range, maybe 150 miles. The U.S. Department of Transportation has found that 78 percent of commutes are fewer than 40 miles round-trip. EREVs and PHEVs provide the range of current gasoline and diesel vehicles. An internal combustion engine drives the vehicle, charges the batteries or both when the batteries are depleted.
Battery cost will decrease as production volume increases, but it still represents a significant portion of vehicle cost, especially for the much larger battery packs needed by all-electric BEVs. Some have proposed selling EVs and leasing the batteries to reduce consumers’ initial investments.
The American Recovery and Reinvestment Act of 2009 (ARRA) encourages the development, manufacture and sale of PEVs. Depending on battery capacity, tax credits range from $2,500 to $7,500 for PEVs acquired before Dec. 31, 2011. Incentives also exist for manufacturers to develop and produce PEVs and highly efficient batteries, as well as electric motors, controllers, chargers and other components.
Charging times are most critical with BEVs. Home charging, or Level 1 charging, using household 120 volts requires eight to 14 hours for a full charge. Level 2 charging, connected to a 208-volt to 240-volt, single-phase source, takes four to six hours. Level 3, fast or rapid charging, requires 480-volt, three-phase current for recharging in 10 minutes or less.
The Nissan Leaf will come with a home charging station installed by AeroVironment’s licensed electricians. It can fully charge the Leaf in eight hours to provide a 100-mile range.
Quick charges have significant disadvantages. A 10-minute quick charge of a 50 kilowatt-hour battery pack from 10 to 80 percent could mean current draw of 875 amps at 240 volts or 440 amps at 480 volt, three-phase power. High currents demand sophisticated, insulated conductors and safety systems. Quick charging can result in excessive heating and a reduced battery life. Or how about the huge amount of electricity delivered to a few quick recharge stations on Interstate 15 between Los Angeles and Las Vegas? Here, every BEV would need to stop for a charge, meaning dozens or even hundreds of fill-ups every hour.
Will the electric grid be able to handle all these PEVs? Recently, the ISO/RTO Council (IRC) studied the impact of a projected one million PEVs on U.S. roads in a decade. The IRC includes U.S. and Canadian power grid operators who manage two-thirds of electricity supplied to U.S. consumers and more than 50 percent of Canada's population. PEV sales are likely to cluster on the West Coast and Northeast, mainly in large urban areas, according to the IRC. There could be nearly 120,000 PEVs in Los Angeles by 2019 and 54,000 PEVs in the New York City metropolitan area.
The IRC study found that if all PEVs were charged simultaneously, they could add an electric load of 3,785 MW. In reality, this load would be drastically less because charging would be staggered. Electric load would increase about one-fifth, or if charging were staggered over eight hours, it would increase about 85 percent if done over 12 hours.
Innovations in energy distribution and storage, smart grid technology and new pricing strategies will be needed to avoid disruptions and minimize price impacts. For example, utilities could store their excess capacity in PEV batteries. Using smart vehicle-to-grid (V2G) technology, utilities could remotely connect to plugged-in PEVs to store electricity in batteries, then withdraw it during peak demand. This would be attractive especially for time- and weather-dependent renewable resources such as solar and wind.
Like a standardized nozzle at every filling station, a standard charging connector is needed. The Society of Automotive Engineers (SAE) International’s Standard J1772 has been adopted as the North American standard for Level 1 and Level 2 charging. The SAE Electric Vehicle Conductive Charge Coupler is a smart connector that provides two-way data transfer to identify vehicles and control charging.
A proximity detection capability prevents problems if a vehicle should move while charging and provides shock protection for safe charging even in wet weather. It is designed for up to 10,000 connection and disconnection cycles, exposure to all elements and has a 27-year life expectancy. The International Electrotechnical Commission’s International (IEC) Standard 62196 covers Level 3 systems with connectors compatible with SAE J1772. Asian and European manufacturers are developing other standards, but the hope is they will be mutually compatible.
This all could mean big business for those supplying the infrastructure to keep PEVs rolling. An ABI Research market study found global investment for EV chargers alone will reach $11.75 billion by 2015. The number of charging stations will grow from 20,000 worldwide today to more than 3 million in five years. The study shows that the U.S. will account for 54 percent of all chargers in 2015, followed by China at 23 percent.
Several companies have developed charging systems and are installing them. ClipperCreek Inc. is one of the first to offer an SAE J1772-compliant charger. ClipperCreek supplies chargers for several EVs, such as Tesla, BMW Mini E, Mitsubishi, Ford Motor Co., Mercedes, General Motors Co., and Nissan EV. AeroVironment Inc. has established a charger installation electrical contractor network and will supply chargers for the Nissan Leaf and Think City. General Electric Co. and Juice Technologies are jointly developing intelligent chargers that integrate GE’s smart meter technology and communication capabilities with Juice Technologies’ intelligent Plug Smart that includes portable devices carried in the trunk for off-peak charging anywhere.
Coulomb Technologies has been installing networked charging stations since 2007, starting with San Jose, Calif. Installations also exist in San Francisco, Houston, Amsterdam, Chicago and Nashville, Tenn. Customers include McDonald’s Corp., Element Hotels, Dell Inc. and DTE Energy Co. Charge points are more than a place to plug in. Coulomb’s ChargePoint Network provides charging status by text message or e-mail notification and can inform motorists of unoccupied charging stations via smart phones.
|An SAE J1772-compliant, UL-listed portable charge coupler cordset for charging from any standard 15 amp wall outlet provides safe charging for PEVs. Courtesy Delphi Corp.|
Car Charging Group Inc. plans to build a nationwide infrastructure using Coulomb’s Level 3 fast-charging stations in parking lots. It will share revenue with operators and plans to have 1,000 units by the end of 2010. Multifamily real estate investment trust UDR Inc. is installing Coulomb networked charging stations at its apartment complexes in Dallas and Addison, Texas.
Have PEVs finally arrived, and will they be sold in serious numbers? Because of concerns for the environment, increasing fuel prices and national security implications of imported oil, Americans view electric-powered transportation more positively. A recent Capital One Auto Finance survey shows that 78 percent of respondents think alternative energy vehicles, including EVs, are here for the long haul.
William “Bill” Siuru Jr. is a retired U.S. Air Force colonel who is the technical editor for the Green Car Journal. The professional engineer has a doctorate in mechanical engineering, was a professor at the U.S. Military Academy at West Point, commanded the research laboratory at the U.S. Air Force Academy, and was director of engineering at Wright-Patterson Air Force Base. Reach him at email@example.com.
Don’t Charge Batteries; Switch Them
An alternative to charging stations are battery switching stations where depleted battery packs are replaced by fresh packs. Such a system is being developed by Better Place. A motorist drives into a switching station and proceeds along a switch-lane conveyor. An automated platform under his or her vehicle aligns under the battery, releases the battery and lowers the battery, then replaces it with a fully charged one. This takes a couple of minutes while the driver sits in the car. The depleted battery is recharged for later use in another vehicle.
Better Place plans to deploy its technology initially in Israel and Denmark by the end of 2011. These locations are ideal because their geographical size means far fewer roadside switch stations. The company recently opened its first demonstration center inside a refurbished oil tank in Israel, one of the last gasoline storage and distribution centers there. Working with Nihon Kotsu Tokyo’s largest taxi operator, Better Place is demonstrating the world’s first switchable-battery electric taxi in Tokyo.
Within minutes, spent batteries are replaced from underneath at a Better Place switching station. Courtesy Better Place
Others developing swapping stations include SwapPack in Texas, which is developing a swap arrangement similar to swapping propane gas tanks at convenience stores. Electric Vehicle Infrastructure Network (EVIN) says its switchable battery concept has a couple of advantages over fast recharging: Batteries do not have to be particularly high-tech with large storage capacities if enough switch stations exist. This also highlights the biggest drawback: the large investment needed for many locations. Also, charging time is no longer an issue because batteries are charged outside of EVs.
A Nissan crossover equipped with A123 Systems lithium-ion battery is being used in a switchable-battery electric taxi demonstration in Tokyo. Courtesy Better Place