Electric vehicle:-Energy source technology

Energy source technology:

Energy sources used in EV & HEVs

• Batteries (stored energy in electric form )
• Ultra capacitor(stored energy in electrostatic form uses high value of capacitance)
• Ultra Flywheels (stores energy in kinetic form)
• Fuel Cells (uses Hydrogen as fuel,stored energy in electric form )

Ragone Plot:

Plot used for performance comparison of energy sources.

Specific energy(w-h/Kg)(Y axis)

Determines the driving range/charge

Specific power(W-H/kg)( X axis)

Determines acceleration rates

Electric vehicle Batteries:

• Valve Regulated Lead Acid(VRLA) (most used battery in electric vehicle applications because it is low cost and its popular in low hand vehicle)
• Nickel Cadmium(Ni-Cd)(Medium, used where high performance is required)
• Nickel Zinc(Ni- Zn)
• Nickel metal hydride (Ni-mh)
• Zinc air (Zn/air)(Mechanical batteries, because electrolyte has to be replaced after each discharge)
• Aluminium air(Al/air)
• Sodium sulphur(Na/S)
• Sodium Nickel chloride(Na/NiCl2)
• Lithium ion(Cost, used where high performance need)

Comparison of Batteries based on :

• Specific energy
• Specific power
• Cycle life
• Cost
• Safety

Types of Li ion batteries:

• Lithium Manganese oxide(LMO)
• Lithium Nickel Manganese cobalt oxide(NMC)
• Lithium ion phosphate (LFP)
• Lithium Nickel cobalt aluminium oxide(NCA)
• Lithium titanate (LTO)
• Lithium/air
• Lithium/sulphur

Ultra Capacitors/Flywheels

UC -

• High specific power, very high life cycle
• Reduction of cost
• Increase in energy storage capacity

UF: (low specific power)

• Vacuum environment to remove air friction
• Bearing loss elimination using magnetic bearing
• Casing is thickened for safety concern

Fuel Cell:

• Direct methanol fuel cell (DMFC)
• Alkaline Fuel Cell
• Proton exchange membrane fuel cell (Solid electrolyte,low temperature & high power density)(PEMFC)
• Phosphate acid fuel cell(PAFC)
• Molten carbonate fuel cell(MCFC)
• Solid Oxide Fuel Cell(SOFC)

On board Renewable energy sources:

• Braking energy
• Solar energy (Photovoltaic generation system)
• Waste heat energy(Possible in HEV, Thermo electric generator)
• Vibration energy(due to road roughness and vehicle dynamics, Regenerative shock absorber & linear PM generator)