A plug-in hybrid electric vehicle (PHEV) includes a traditional combustion engine with an electric motor that can be recharged with an external power source, such as a home electric outlet. Battery electric vehicles (EVs) work by storing electricity from the grid in a large battery.
The advantages of electricity as a fuel are that electric vehicles produce no tailpipe emissions, and electricity helps reduce the transportation sector’s reliance on fossil fuel.
PHEV and EV market growth has been hampered by “range anxiety”, consumers’ fear of being stranded because of poor battery performance or a lack of charging infrastructure. For the PHEV and EV markets to expand, developing charging infrastructure is a priority. This effort allows for charging at multiple locations, including at home and at public stations, and helps reduce consumer range anxiety.
Charging equipment is classified by the maximum amount of power in kilowatts provided to the battery. There are several levels of charging equipment. In North America, the standards are:
AC Level 1, which is a 120-volt (V) alternating current (AC) plug. A full charge at Level 1 can take between 8 and 20 hours, depending on the battery capacity of the vehicle. Charging rate is approximately 1 kW.
AC Level 2, which is a 240-volt AC plug and requires installation of home charging equipment. Level 2 charging can take between 3 and 8 hours, again depending on the battery capacity of the vehicle. Charging rates fall within a range of 3 kW to 20 kW.
Direct Current (DC) fast charging, which is as high as 600 V, enables charging along heavy traffic corridors and at public stations. A DC fast charge can take less than 30 minutes to charge a battery to most of its capacity.
Asian and European countries are evolving charging standards that seek to harmonize with but may not be identical to these standards. Discussions towards broader international standards are ongoing.
It is expected that most PHEV and EV owners will recharge their vehicles overnight at home. Level 1 and Level 2 charging equipment will be the primary option for home charging. Vehicle manufacturers have already developed stations for home charging. For example, according to Nissan, in order to “pre-wire” a home charging dock for the Leaf EV, a 220/240 V 40-amp dedicated circuit is required.
Public charging stations will make PHEVs and EVs more convenient, help allay range anxiety, and increase these vehicles’ useful range. Public charging stations use Level 2 or DC fast charging, and are located in high-density locations, such as shopping centers, parking lots, and garages.
Electricity costs versus gasoline
For EV and PHEV charging—the stability, planning benefits, and lower cost of household electricity rates offer an attractive alternative compared to petroleum-based transportation. Fuel efficiency of a PHEV or EV is usually measured in cost per gallon (or liter) rather than miles per gallon (or kilometers per liter). To calculate the per distance cost of an electric vehicle, the cost of electricity in dollars per kilowatt-hour (kWh) and the amount of electricity used to travel one mile or kilometer must be known.
Standardization in charging outlets assures that all vehicles can be charged at any charging outlet. North America had agreed on standards. Many European countries are in the process of discussing standards for charging infrastructure.
IA-HEV Work on charging equipment
Task 18, EV Ecosystems, launched in 2011 and will capture practical experience from cities, regions, and businesses that are pioneering advanced plug-in EV pilot programs. Task 20, Quick Charging, is exploring many aspects of DC fast charging, mentioned above.