Electric vehicle basics, Study Guides, Projects, Research of Electrical Engineering

Download Electric vehicle basics and more Study Guides, Projects, Research Electrical Engineering in PDF only on Docsity! Electric Vehicle Basics Electric vehicles (EVs) use electricity as their primary fuel or to improve the effciency of conventional vehicle designs. EVs include all-electric vehicles, also referred to as battery electric vehicles (BEVs), and plug-in hybrid electric vehicles (PHEVs). In colloquial references, these vehicles are called electric cars, or simply EVs, even though some of these vehicles still use liquid fuels in conjunction with electricity. EVs are known for providing instant torque and a quiet driver experience. Other types of electric-drive vehicles not covered here include hybrid electric vehicles, which are powered by a conventional engine and an electric motor that uses energy stored in a battery that is charged by regenerative braking, not by plugging in, and fuel cell electric vehicles, which use a propulsion system similar to electric vehicles, where energy stored as hydrogen is converted to electricity by the fuel cell. All-Electric Vehicles All-electric vehicles do not have conventional engines but are driven solely by one or more electric motors powered by energy stored in batteries. The batteries are charged by plugging the vehicle into National Highway Travel Survey, U.S. Department of Transportation, Federal Highway Administration, 2008, fhwa.dot.gov/policyinformation/pubs/pl08021/ fig4_5.cfm. Electric vehicles are charged by plugging the vehicle into an electric power source. Photo courtesy of Forth. an electric power source and can also be charged through regenerative braking. All-electric vehicles produce no tailpipe emissions, although there are “life cycle” emissions associated with the electricity production. All-electric vehicles typically have shorter driving ranges per charge than conventional vehicles have per tank of gasoline. Most new BEVs are designed to travel between 110 and over 300 miles on a fully charged battery, depending on the model. For context, 90% of all U.S. household trips cover less than 100 miles.1 An all-electric vehicle’s range varies according to driving conditions and driving habits. Extreme temperatures tend to reduce range because energy from the battery powers climate control systems in addition to powering the motor. Speeding, aggressive driving, and heavy loads can also reduce range. Regenerative Braking Regenerative braking allows EVs to capture energy normally lost during braking by using the electric motor as a generator and storing that captured energy in the battery. Plug-In Hybrid Electric Vehicles PHEVs use batteries to power an electric motor and use another fuel, such as gasoline, to power a conventional engine. The batteries are typically charged by plugging the PHEV into an electric power source, although they can also be charged by the conventional engine and through regenerative braking. PHEVs have an all-electric driving range of about 15 to 60+ miles, depending on the model. As long as the battery is EVs at a Glance EVs run on electricity alone. They are powered by one or more electric motors and a battery. The battery is charged by plugging the vehicle into an electric power source and through regenerative braking. PHEVs can travel moderate distances on electricity alone. The battery can be charged by plugging into an electric power source, through regenerative braking, and by the engine. PHEVs don’t have to be plugged in before driving. They can also be fueled solely with conventional fuel. However, they will not achieve maximum fuel economy or take full advantage of their all-electric capabilities without plugging in. 1 Getting started with an EV is easy thanks to the charging “cordset” that comes with most vehicles. Photo by Erik Nelsen, NREL 64277. 2 fhwa.dot.gov/environment/alternative_fuel_corridors charged, a PHEV can draw most of its power from electricity for typical daily driving. The engine will then power on when the battery is mostly depleted, during rapid acceleration, at high speeds, or when intensive heating or air conditioning is required. When running on battery power alone, PHEVs produce no tailpipe emissions. Even when the conventional engine is running, PHEVs typically consume less gasoline and produce fewer emissions than similar conventional vehicles. What EV Models Are Available? Nearly all major vehicle manufacturers have EV models available, and some have committed to transitioning to selling only EVs by 2030. Medium- and heavy-duty options are also available for fleet applications. See Considering an EV for fleet-specific considerations. For up-to-date information on available models, use the Alternative Fuels Data Center (AFDC) Vehicle Search tool (afdc. energy.gov/tools) or the Find a Car tool on FuelEconomy.gov (fueleconomy.gov/ feg/findacar.shtml). More heavy-duty vehicle manufacturers are now offering plug-in models for feets. Photo by Dennis Schroeder, NREL 46574. How Do These Vehicles “Fuel Up”? Charging equipment provides electricity to charge EV batteries. The charging unit communicates with the vehicle to ensure that it supplies an appropriate and safe flow of electricity. There are more than 140,000 publicly available charging outlets—and counting—across the country. Most currently available light-duty BEVs have ranges between 110 and over 300 miles. Technological advances such as larger batteries and growing access to charging are increasingly addressing “range anxiety,” or the fear of running out of charge. Learn more about trends in EV charging infrastructure (afdc.energy.gov/ fuels/electricity_infrastructure_trends. html). It may take as little as 30 minutes to fully charge an EV’s battery, but charging times vary based on the type or level of charging; the type of battery, its capacity, and how depleted it is; and the capacity of the vehicle’s internal charger (see Charging Options table). Charging units can be installed in residential, fleet, workplace, and public settings. Most EVs come with a 110-volt “Level 1” cordset that can be plugged into a typical electrical outlet. For quicker charging, homeowners can install a 240-V “Level 2” unit on a dedicated electrical circuit. This can often be done with little or no required electrical upgrades, as most homes have 240-V service for appliances like dryers and electric ranges. A Level 2 unit can be portable or “hard wired” into a building and can be purchased for as little as $200. For more information on installing charging equipment, see Charging Infrastructure Procurement and Installation on the AFDC (afdc.energy. gov/fuels/electricity_infrastructure_ development.html). To make long-distance travel more accessible, the Federal Highway Administration is establishing a network of alternative fueling and charging infrastructure along highway corridors. Designated EV corridors2 supported by DC fast charging stations are under development nationwide. To find public stations, use the Alternative Fueling Station Locator (afdc.energy.gov/ stations), which is available as an iPhone and Android app. Equipment Types and Costs Charging units are classified according to the rate at which they charge batteries. Two types—Level 1 and Level 2— provide AC power to the vehicle, with the Charging Made Simple Most EV owners charge at home or at work because charging is more convenient and cost-effective than using public stations. But public equipment is also easy to use. Depending on the station, drivers might use a network card, credit card, phone, cash, or even just enter an account number. There are also free chargers where users can just plug in. An added beneft of going electric is that electricity prices are less volatile than gasoline and diesel prices, so drivers can more easily forecast their fueling expenses. See a comparison of all fuel prices over time on the AFDC Fuel Prices page (afdc.energy.gov/fuels/prices.html). 2