4. Storage for EVs
Ashok Jhunjhunwala,
Indian Institute of Technology, Madras
Chapter 4.0 Fundamentals of Electric Vehicles: Technology & economics
,4.1 Introduction to Battery
parameters
Chapter 4.0 Fundamentals of Electric Vehicles: Technology & economics
,EV Battery (rechargeable electric batteries)
Is a storage of Energy (electric) for an Electric Vehicles
◦ Replaces a petrol-tank in a ICE vehicle: storage of fuel (petrol) used to drive a vehicle
As discussed in Chapter 1, even taking into account four-times higher drive
efficiency of EV vis-à-vis ICE engine, Battery
◦ weight 10-12 times higher than filled petrol-tank per km of drive
◦ size 5 to 6 times higher than petrol tank required per km of drive
◦ costs is much-much higher than an empty petrol tank
◦ But cost of petrol per km much higher than electricity costs per km
Battery has much higher CAPEX, but EV has much lower OPEX
◦ Why is battery costs so high? Let us understand Battery
https://doi.org/10.1039/
Chapter 4.0 Fundamentals of Electric Vehicles: Technology & economics
, Understanding Battery Parameters
Consider a Battery of 48 Volts with a Capacity C of 15 kWh
◦ Battery capacity can also be defined by its Ampere-hour (Ah)
◦ Battery Ah = C/voltage = 15000 Wh / 48V ≈ 300 Ah
◦ or a Battery C = Battery voltage * Battery Ah
State of Charge (SoC) of battery is a measure of percentage of battery charged
◦ SoC of 0% means discharged battery; SoC of 100% is fully charged battery (having 15 kWh energy)
◦ Output Voltage of a Battery-pack varies with its SoC
◦ For a 48V Li-Ion battery, voltage varies from 43 to 56V depending upon the State of Charge (SoC)
◦ 43V when SoC is near zero and 56V when SoC is near 100%
Chapter 4.0 Fundamentals of Electric Vehicles: Technology & economics
Ashok Jhunjhunwala,
Indian Institute of Technology, Madras
Chapter 4.0 Fundamentals of Electric Vehicles: Technology & economics
,4.1 Introduction to Battery
parameters
Chapter 4.0 Fundamentals of Electric Vehicles: Technology & economics
,EV Battery (rechargeable electric batteries)
Is a storage of Energy (electric) for an Electric Vehicles
◦ Replaces a petrol-tank in a ICE vehicle: storage of fuel (petrol) used to drive a vehicle
As discussed in Chapter 1, even taking into account four-times higher drive
efficiency of EV vis-à-vis ICE engine, Battery
◦ weight 10-12 times higher than filled petrol-tank per km of drive
◦ size 5 to 6 times higher than petrol tank required per km of drive
◦ costs is much-much higher than an empty petrol tank
◦ But cost of petrol per km much higher than electricity costs per km
Battery has much higher CAPEX, but EV has much lower OPEX
◦ Why is battery costs so high? Let us understand Battery
https://doi.org/10.1039/
Chapter 4.0 Fundamentals of Electric Vehicles: Technology & economics
, Understanding Battery Parameters
Consider a Battery of 48 Volts with a Capacity C of 15 kWh
◦ Battery capacity can also be defined by its Ampere-hour (Ah)
◦ Battery Ah = C/voltage = 15000 Wh / 48V ≈ 300 Ah
◦ or a Battery C = Battery voltage * Battery Ah
State of Charge (SoC) of battery is a measure of percentage of battery charged
◦ SoC of 0% means discharged battery; SoC of 100% is fully charged battery (having 15 kWh energy)
◦ Output Voltage of a Battery-pack varies with its SoC
◦ For a 48V Li-Ion battery, voltage varies from 43 to 56V depending upon the State of Charge (SoC)
◦ 43V when SoC is near zero and 56V when SoC is near 100%
Chapter 4.0 Fundamentals of Electric Vehicles: Technology & economics
