In an EV, the battery is not so easy to design because of
the following requirements: high energy density, high power
density, affordable cost, long cycle life time, good safety,
and reliability, should be met simultaneously. Lithium-ion
batteries are recognized as the most competitive solution to
be used in electric vehicles [1]. However, the energy density
of the commercialized lithium-ion battery in EVs is only
90–100Wh/kg for a finished pack [2].1 This number is so poor
compared with gasoline, which has an energy density about
12 000 Wh/kg. To challenge the 300-mile range of an internal
combustion engine power vehicle, a pure EV needs a large
amount of batteries which are too heavy and too expensive.
The lithium-ion battery cost is about 500$/kWh at the present
time. Considering the vehicle initial investment, maintenance,
and energy cost, the owning of a battery electric vehicle will
make the consumer spend an extra 1000$/year on average
compared with a gasoline-powered vehicle [1]. Besides the
cost issue, the long charging time of EV batteries also makes
the EV not acceptable to many drivers. For a single charge,
it takes about one half-hour to several hours depending on
the power level of the attached charger, which is many times
longer than the gasoline refueling process. The EVs cannot
get ready immediately if they have run out of battery energy.
To overcome this, what the owners would most likely do is
to find any possible opportunity to plug-in and charge the
battery. It really brings some trouble as people may forget
to plug-in and find themselves out of battery energy later on.
The charging cables on the floor may bring tripping hazards.
Leakage from cracked old cable, in particular in cold zones,
can bring additional hazardous conditions to the owner. Also,
people may have to brave the wind, rain, ice, or snow to plugin
with the risk of an electric shock.
In an EV, the battery is not so easy to design because ofthe following requirements: high energy density, high powerdensity, affordable cost, long cycle life time, good safety,and reliability, should be met simultaneously. Lithium-ionbatteries are recognized as the most competitive solution tobe used in electric vehicles [1]. However, the energy densityof the commercialized lithium-ion battery in EVs is only90–100Wh/kg for a finished pack [2].1 This number is so poorcompared with gasoline, which has an energy density about12 000 Wh/kg. To challenge the 300-mile range of an internalcombustion engine power vehicle, a pure EV needs a largeamount of batteries which are too heavy and too expensive.The lithium-ion battery cost is about 500$/kWh at the presenttime. Considering the vehicle initial investment, maintenance,and energy cost, the owning of a battery electric vehicle willmake the consumer spend an extra 1000$/year on averagecompared with a gasoline-powered vehicle [1]. Besides thecost issue, the long charging time of EV batteries also makesthe EV not acceptable to many drivers. For a single charge,it takes about one half-hour to several hours depending onthe power level of the attached charger, which is many timeslonger than the gasoline refueling process. The EVs cannotget ready immediately if they have run out of battery energy.To overcome this, what the owners would most likely do isto find any possible opportunity to plug-in and charge thebattery. It really brings some trouble as people may forgetto plug-in and find themselves out of battery energy later on.The charging cables on the floor may bring tripping hazards.Leakage from cracked old cable, in particular in cold zones,can bring additional hazardous conditions to the owner. Also,people may have to brave the wind, rain, ice, or snow to pluginwith the risk of an electric shock.
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