An electric vehicle used electric motors or traction motors for propulsion. Electric vehicles have been used since the 19th century when electricity was preferred to the internal combustion engine due to the level of comfort and ease of operation it offered it’s users. However, the internal combustion engine became the dominant mode of propulsion for cars into the 21st century, but improvements in technology over the last ten years have seen a renewed interest in electric vehicles also known as EVs. Electric vehicles can be powered through a collector system by electricity from off vehicle sources or may be self contained with a battery, solar panels or electric generator to convert fuel to electricity. Examples of electric vehicles include road and rail vehicles, underwater craft, surface vessels, electric aircraft and electric space vehicles.
ONBOARD GENERATORS AND HYBRID ELECTRIC VEHICLES
There are many sources of power available to hybrid electric vehicles such as
. Power generated onboard using a diesel engine used for diesel electric trains.
. Power generated onboard using fuel cell, used for fuel celled vehicles.
. Power generated onboard using nuclear power used to propel nuclear submarines, aircraft carriers and large surface warships such as cruisers.
. Renewable energy sources such as solar power used for solar vehicles.
Hybrid EVs can also derive electricity from multiple sources such as;
. Onboard rechargeable electricity storage system with direct continuous connection to land based power plants for unlimited range coverage for these vehicles.
. Onboard rechargeable electricity storage system and internal combustion engine plug in hybrid.
CONNECTION TO POWER PLANTS
Direct connection to power plants which is commonly used for electric trains, trolley buses and electric trucks. Another include online electric vehicles which collect power from electric power strips buried under the road surface through electromagnetic induction.
LITHIUM ION BATTERY
Most electric vehicles use lithium ion batteries as a source of power. Lithium ion batteries have higher energy density,longer life span and higher power density compared to other battery types. Other factors to be considered include cost, safety durability and thermal breakdown. By increasing the lifespan of the battery, the cost of frequently replacing worn out batteries is brought down considerably. The improved technology in making long lasting lithium ion batteries have brought the cost down, invariably decreasing the cost of electric vehicles.
The power of a vehicle’s electric motor is as other vehicles is measured in kilowatts. k100ilowatts is roughly equal to 134 horsepower. Electric motors can deliver their maximum torque over a wide RPM range. This means that a vehicle with a 100 kw electric motor exceeds that of a vehicle with a 100 kw internal combustion engine which can only deliver it’s maximum torque within a limited range of speed. Energy is lost during the process of converting electrical energy to mechanical energy. Approximately 90 percent of the battery energy is converted to mechanical energy, the other being lost to the motor and drive train. Direct current is usually fed to a DC /AC inverter where it is converted to alternating current AC electricity and the AC electricity is connected to a 3 phase AC motor. For electric trains, forklifts and some electric cars DC motors are often used. Other types use universal motors and in newer electric vehicles, induction motors or permanent magnet motors are used.