1. Outline
1.0 Overview of Electric Vehicles in India
2.0 Vehicle dynamics
3.0 Vehicle Subsystems: EV Power-train and Accesories
4.0 Storage for EVs: Characteristics of Battery Packs and Cells
5.0 Fundamentals of EV Battery Pack design
6.0 EV Motors and Controllers: Fundamentals and Design
7.0 Battery Charging and Swapping
8.0 Management of EV Infrastructure
3. INTRODUCTION
An electric vehicle, also called an EV, uses one or more electric motors or traction
motors for propulsion instead of the traditional fossil fuel.
• First electric carriage was built in 1830s and the first electric automobile was
built in 1891 in the United States.
• Types : Battery electric Vehicle
Hybrid Electric Vehicle Plug-in Hybrid Electric Vehicle
Fuel Cell Electric Vehicle
• Electric vehicles will play a pivot role in changing the environment and economy
around the globe in the next two decades.
4. Why so much interest in
EVs?
14
of 20 most
polluted
world-cities in
India
36%NOx emissions
due to vehicles
PM2.5
emissions in
20%Delhi due to
vehicles
Petroleum consumption up from 32.5 mill
tons in 1981 to 184.7 mill tons in 2015
40x
Increase in import
bill of petroleum
products
Air quality
in Indian
cities
Note clean air
during
COVID19 • EV is four-times as energy
efficient as ICE
• ICE efficiency: 22% to 23% Vs EV
motor energy efficiency: 90%
• has 50 times less moving parts
8. • The average on-road price of electric vehicles in India is not attractive enough for consumers.
• Inadequate charging infrastructure.
• Reliance on battery imports.
• Range anxiety among consumers.
• Inadequate electricity supply in parts of India
. • Lack of quality maintenance and repair options
. • Changing the mindset of consumers, i.e adopting to a new technology
Challenges in Indian EV Industry
11. Li-Ion Energy density continuously increasing
Gravimetric ED of NMC and NCA cells is in between 250 to 300 Wh/kg today
◦ LFP cell density saturated at 150 Wh/kg: theoretical limit of 160 Wh/kg
◦ Towards 400 to 500 Wh/kg in coming years: NMC with Graphite-Silica anode
Volumetric Energy Density of NMC cells touching 500 Wh/litre
◦ Other variants of Li-battery may emerge to drive energy density higher
Higher energy-density: higher safety concerns
Cost of battery inversely related to its energy density
◦ Main driver of cost reduction
◦ Higher energy-density: lower use of materials like Lithium,
Cobalt, Nickel, Manganese, Graphite
6
Energy Density
(Wh/kg)
2011:
80
2015 :140
2018:220
2020: 310
Cell-price
per kWh
$800
$275
$140
$110
12. India’s Vehicles dominated by
two-wheelers
Category 2013-14 2014-15 2015-16 2016-17 2017-18 2018-19
Passenger Vehicles 2.50 2.60 2.79 3.05 3.29 3.38
Commercial
Vehicles
0.63 0.61 0.69 0.71 0.86 1.01
Three Wheelers 0.48 0.53 0.54 0.51 0.64 0.70
Two Wheelers 14.81 15.98 16.46 17.59 20.20 21.18
Grand Total 18.42 19.72 20.47 21.86 24.98 26.27
Percentage of Cars sold in India
Price Range 2015-16 2016-17 2017-18
Below ₹500,000 28.02 28.85 27.43
₹500K to 1 million 55.49 54.96 56.48
₹1 to 1.5 million 15.29 15.23 14.65
Above ₹1.5 million 1.20 0.96 1.43
No of Vehicles (million) sold in India excluding e-rickshaw
• Three wheelers have become the main last-mile
public transport for 75% Indians
• Cars 14% of total vehicles
– Premium Cars with costs more than ₹
1M: about 15%
13. 95%
India’s auto-segment different from that in most of the world: small and
affordable vehicles
◦ Domination of 2-wheelers: 79%
◦ Autos including small goods vehicle: 4% (rickshaw not included)
◦ Economy Cars costing below ₹
1 million: 12%
◦ Premium Cars costing above ₹
1 million: 2%
◦ Buses and large goods vehicle (including trucks): 3%
India’s vehicles and affordability
14. India’s EV Strategy
Two-wheelers, Three-wheelers and small four-wheelers (cost less than ₹
1
million) constitute 95% of Indian vehicles and buses and trucks about 3%
◦ Price point in India much lower that that in the West, driven by affordability
Can India get leadership in designing and developing these affordable vehicles?
◦ As it has done for these vehicles with ICE
◦ Design every sub-system in India and manufacture them
Premium four-wheelers (2% of Indian vehicles): similar to that in rest of world
◦ India could learn and adopt; encourage multinationals to manufacture them in India
◦ Will help us build a stronger ecosystem for components and subsystems
15. EVs Costs in India and Energy per km
15
EVs without battery costs less than an equivalent ICE vehicle
◦ As ICE drive-train gets replaced by EV drive-train
◦ But whereas ICE requires a low-cost petrol-tank to store fuel (energy), EV requires an
expensive Battery to store energy
Battery is extra cost in EV and is a dominant cost
◦ Focus on higher energy-efficiency: fकतना देती है for EVs (kms/litre of petrol)
◦ Lower the energy (Wh/km) used per km, lower is the battery size and its cost to drive
certain range
◦ size and weight of the battery reduces: in fact enhancing efficiency further
Efficiency improved by improving Motor/ Controller efficiency, better tyres
(lower rolling resistance), better vehicle-aerodynamics and lower weight
16. Capital and Operational Cost of EV
Battery
Chapter 1.0 Fundamentals of Electric Vehicles: Technology & economics 16
Battery Size (kWh) 1 2 3 4
BatteryCap Cost (₹) 18000 33000 45000 54000
Energy Eff (Wh/km) Range with Battery Size (kWh)
Two-wheelers 15 56.7 113.3 170.0 226.7
20 42.5 85.0 127.5 170.0
25 34.0 68.0 102.0 136.0
30 28.3 56.7 85.0 113.3
Auto 40 21.3 42.5 63.8 85.0
50 17.0 34.0 51.0 68.0
EV Operation Cost less than ₹
8 /kWh
Battery Capital Costs
◦ As Energy Efficiency of vehicle increases
(say from 25Wh/km to 15 Wh/km), one
gets higher range for same battery-size
◦ Or Battery size reduces for same range
◦ Implies lower capital Costs
17. Battery Cost Reduction Strategy
1. Increase Energy-efficiency of EV
◦Battery size reduced by 35% to 40% over last three years in India
70 to 80 Wh/km
◦ For e-autos: from to 45/50 Wh/km
1600 Wh/km
◦ E-buses: from to 900 Wh/km
2. Reduce battery Size
◦ Smaller battery will reduce costs
◦ But that will limit its vehicle range (range-anxiety): Never an issue in ICE
vehicles as petrol tank costs are low
◦ Further, charging the Vehicle Battery takes a long time: Much larger than
that of filling petrol in a ICE vehicle
Battery size
without range
anxiety
Chapter 1.0 Fundamentals of Electric Vehicles: Technology & economics 17
35-40%
reduction
18. Approach I: Business viability for Public
Transport
Split battery into smaller size (one third) and swap
◦ No waiting time to charge battery: no public charging infrastructure required
◦ Smaller Battery size makes EV highly affordable: comparable to petrol vehicles
◦ no further economic challenge or technical challenge
◦ Engineering Challenges for battery-swapping need to be overcome
To make Public Vehicles affordable
Battery size
without range
anxiety
swap
Battery-life severely affected by Fast Charging at 45 deg C
◦ Swapped battery chargeable in conditioned environment, in two hours to maximise its life
◦ Also possible to cool while charging (discussed later)
swap
swap
19. Battery Swapping Advantage
19
Separate vehicle business (without battery) and energy business
(Energy Operator)
◦ Capital cost of vehicle similar to that for petrol / diesel vehicle
◦ Operation cost today same as petrol / diesel vehicle
◦ WITH limited SUBSIDY, electric autos and buses can compete today with ICE vehicles
Volumes for public vehicles would make them highly affordable
◦ Get Fleet Operator company to buy vehicles in bulk and lease
◦ Get Energy Operators (EOs) to buy batteries in bulk and set up energy business
Capital cost of vehicle less than that for petrol vehicles, and ₹
/km operation costs
same as petrol / diesel / CNG
20. Approach II: Private Vehicles
20
Batteries dominate the cost of an EV
◦Larger battery increase costs (Tesla uses battery for 540 kms)
◦ and also vehicle weight (reducing the energy efficiency or kms/kWh)
◦Smaller battery creates range anxiety
◦ Use Public Fast Charger: waiting time + public charging infrastructure
◦ Fast Charge in 45 to 60 minutes: too long a wait and impacts battery-life
◦ Very fast Charge (15 to 20 minutes): possible but significantly impacts battery life or
require very expensive battery
◦ gets worse as temperature crosses 40°C
21. Answer: Range-extender Batteries
21
Use Electric vehicles with two small-battery slots
◦ One would have Fixed low-cost limited-range battery: purchased along with vehicle
◦ Limited range battery: example 100 km range for e-car enough to drive within cities on 90% of the days or
(50 km for e-scooter)
◦ Use only night-time Slow Charging: maximising battery life
◦ Second would be an empty slot to add a Range-extension Battery when needed
◦ Swap-in the second (swappable) battery doubling the range at a petrol pump (3 minutes)
◦ enabling another 100 kms range for a e-car or 50 km for a 2-wheeler
◦ Swap the swappable battery again for still longer range (300 kms or 400 kms): No Public charger needed,
No need to wait for charging
Swapping by Energy Operators who purchases battery and leases charged batteries
22. Approach III: Conventional Approach
Choose right size batteries for desired range (without anxiety)
◦ Slow-charge normally
◦ Fast Charge when needed: may impact battery-life
◦ Where does one Charge the vehicles?
◦ At homes?
◦ At public places?
Do the Charger / batteries need standardisation?
Do Swappable Batteries need Standardisation?
23. A bit about batteries
Battery Capital Costs are high
25. Battery-life: depends on multiple factors
Number of charge-discharge Cycles of a battery depends on
◦ Battery-Chemistry used (manufacturer dependent)
◦ Rate of Charging and Discharging (higher rate reduces life)
◦ Usage Temperature (above and below 25°C hurts life)
◦ Operation-region of charge-discharge (Depth of Discharge or DoD) used
◦ Calendar-life
State of Health (SoH) is a measure of Battery Capacity remaining (as compared
to initial Capacity) as the battery is used
◦ A EV battery at End of life (EoL), when its capacity reduces to 75% or 80% of initial capacity
◦ Will limit vehicle range to 75% to 80% of the initial Range when battery is near EoL
26. Typical Battery-life and charging
Battery life dependent on Rate of Charging
◦ Battery life best when charged slowly (four to six hours at 25°C)
◦ Fast charge (in one hour or less) impacts battery life
Typical battery life: 500 to 2000 charge-discharge cycles (slow-charge)
◦ Battery with 500 to 1000 cycles costs low
◦ Battery with 1500 to 2000 cycles quite common and is medium costs
◦ Battery with 3000 to 4000 cycles or more costs high
◦ Batteries with capability of fast charge / discharge costs much higher
27. How many cycles does one need?
Depends on how much distance vehicle will drive in its life-time?
◦ What is the size of the battery (how much range will it provide for a vehicle)?
◦ 600 km range car-battery: 800 to 1000 cycles gives 500,000 km total life
◦ Occasional Fast Charge is OK
◦ 100 km range car-battery: one needs at least 2000 cycles to get 200,000 km life
◦ Fast Charge may impact this further
◦ 50 km range scooter-battery: again require 1500 cycles minimum to get 75,000 km life
◦ 600 km range car-battery can Fast Charge (45 minutes full charge) about 150 kms in ten
minutes (quarter battery): Battery is very expensive
◦ 100 km range car-battery with similar Fast Charge would charge only 25 kms in 10 minutes
29. Does Charging / Swapping need
Standardisation?
What standardisation is a must?
◦ Connector: plugs and sockets
◦ Voltage, Current and Maximum Power
◦ Communication to vehicle?
◦ Communication with Energy Supplier:
Charging Operator or Utility Manager
◦ Metering: how does one bill customer?
◦ Protection
Desirable standardisation for
Swapping
◦ Maximum weight / size of batteries for
each category (2W or 3W-auto) of vehicles?
◦ As EO buys battery and lease, will help in
logistics, stocks and finances
◦ Performance, Chemistry etc. need not be
standardised
A new business known as ENERGY
OPERATOR (EO) may carry out
charging as well as swapping of
batteries
30. Battery Swapping
EO sets up Battery Swapping Infrastructure at convenient locations
◦ Enrols customers who would lease EO’s swappable batteries for their vehicles
◦ Will swap a discharged battery with a charged battery at any of the locations anytime
EO purchases and owns batteries
◦ Has Bulk Chargers at these locations to charge the incoming discharged batteries and offer
charged batteries to customers enrolled
◦ Customers pay for Energy Used in the batteries
◦ Charges will take into account depreciation and interest costs for purchased batteries, infra-costs,
electricity cost and operations cost, besides EO’s profit
Swappable batteries designed so that they can not be charged anywhere
except by EO at its Bulk- chargers (Locked-Smart Batteries)
31. Charging Strategy for best battery-life
Best Charge: SLOW at homes in nights
◦ or two to three hours SLOW charging at office or parking lots
◦ Will use on-board charger: what kind of on-board charger does vehicle have?
◦ 15 Amp single phase charging (up to 3 kW) for two-wheelers, three-wheelers or small
four-wheelers
◦ Three phase charging (6 kW to 20 kW) for larger vehicles with larger battery
Only occasional FAST charging
◦ Long-distance trips, vacations
◦ Charging during restaurant visits
Buses and Taxis may need regular FAST charging
32. Chargers at Public places
Where?
◦ Petrol pumps: NO SPACE -- pumps designed for servicing a vehicle in 3 to 5 minutes
◦ Vehicles need to keep moving IN and OUT: Do not have space for longer-time parking / services
◦ Petrol-pumps charging may be OK if FAST charging possible in five minutes
◦ Swapping at petrol pumps in three to five minutes is OK
◦ Office and Street parking, Parking lots, shopping /food complex parking -- Yes
◦ Can not block space for charging -- but charge while being parked
◦ What kind of Public chargers?
◦ Slow Public Chargers: can be same as used in multi-storied building
◦ Fast Chargers: how fast? What kind of vehicles and batteries
33. 1.5 Where will we get Lithium
for batteries?
or will we for ever import Lithium, Nickel, Cobalt, Manganese and Graphite!
34. Li Ion Batteries for EV
Battery-pack design
◦ thermal design for Indian temperature and driving conditions
◦ Low-cost Cooling mechanism to withstand 45°C ambient
◦ Mechanical design to ensure cells do not bulge on Indian roads
◦ Battery Management Systems to get the best out of each cell
◦ Safety is a major concern: handled by BMS
Cell manufacturing: technology changes every two years
◦ Need technology which stays ahead in energy density
Battery Materials: mostly imported
Cell to Pack
Manufacturing
(35% value)
Cell Manufacturing
(25% value)
Battery Materials (40%
value)
Chapter 10 34
38. ICE drive-train to EV drive-train:
common parts
● Body/frame: Body and frame of the
existing ICE car
● Doors & power windows: Existing
● Wheels: All wheel components
including the rim, hub, knuckle, tyres
● Suspension system: Existing system
including the lower arm and the
struts
● Power Steering system: hydraulic to
electric
● Power Braking system: hydraulic to
electric -- Vacuum pump to actuate
the braking system
● Safety system: All airbags and parking
sensors
● Wipers & fluid pump: Existing Wiper
liquid pump & vipers
● Mirrors: Electronics/Manual mirrors
● Interiors: All interiors including seats,
seat belts, A/C vents, Cabin lights and
other interior components
39. ICE to EV
Parts & Components to be Modified
◦ Air conditioning system: Integration of
variable speed DC motor for existing
hydraulic actuated AC compressor
◦ Cooling system: Can be reused for motor &
batteries with electric water pump
integration
◦ Dashboard may need some modifications
Parts and components to be removed
◦ Fuel tank: Remove fuel tank and associated
connections
◦ Engine: Remove engine and associated
connections like sensors
◦ Clutch & transmission: to be removed since
a single speed transmission system used
◦ ECU and Connections other sensors
◦ Fuel pump and other engine subsystems
40. ICE to EV: to be added
Chapter 1.0 Fundamentals of Electric Vehicles: Technology & economics 40
● Electric Motor: High performance electric motor used for traction
● Motor Controller: Motor controller for motor drive with closed loop
feedback system
● Transmission system: High efficiency transmission system with reduction
system for high acceleration
● Battery Pack with BMS: Reliable battery pack with BMS with CAN
communication and support
● IoT and telematics: IoT for vehicle data collection combined with latest
technology telematics & data infrastructure to monitor & manage vehicle
41. ICE to EV: to be added (to be continued)
Chapter 1.0 Fundamentals of Electric Vehicles: Technology & economics 41
● DC-DC Converters: Efficient DC-DC converter for other peripherals
● Vehicle control unit/ Master control unit: A dedicated VCU/MCU for
vehicle management and safety
● Isolation circuits: Isolation circuits for vehicle and user safety
● Charging infrastructure: Charing port and charging system for vehicle
● On-board charger
● External charger
● Software and Remote Monitoring
42. Driving an ICE or Electric Vehicle
How much Power is required to drive a vehicle?
How much Energy is required to carry out a road-trip?
◦ What is the composite mass of the vehicle (including passenger and goods): Gross Vehicle
Weight (GVW)
◦ What is the condition of the roads (rolling resistance)
◦ What is the aerodynamics of the vehicle (Aerodynamic drag)
◦ What is the incline that it needs to traverse? (Gradient Resistance)
◦ What are the velocities and accelerations at different points of time (Drive Cycle)
◦ What is the maximum speed and maximum acceleration of the vehicle?
43. What does tractive force overcomes?
◦ Aerodynamic Drag
◦ Rolling Resistance
◦ Uphill Resistance
◦ Acceleration
𝟏 2
Aerodynamic Drag = *ρ*CD*A*v
𝟐
◦ v = velocity (m/sec)
◦ Air density @27°C = ρ = 1.2 (kg/m3)
◦ Vehicle Frontal Area or Projected Area =A (sq. m)
◦ Drag coefficient = CD
Aerodynamic
drag
Rolling
Resistance
θ
mg
44. Forces acting on a vehicle in motion
Rolling Resistance = m*g*μ*cosθ
◦ Permissible load = m (kg)
◦ Weight = mg (newton or kg.m/s²), where g
= 9.80665 m/s²
◦ μ = rolling coefficient
Uphill Resistance or Climbing Force =
mg sinθ
◦ Maximum grade = θ° = θ*π/180 radians
Tractive force created by power-train first overcomes
these resistances and then provides acceleration
Aerodynamic
drag
Rolling
Resistance
θ
mg
Grade/Inclination:
Grade in % = Height of grade p
Base of the grade *100 % = b *100 %
Grade in Degree = 𝑡𝑎𝑛−1 𝑝
𝑏
p
b
45. Comparing Force and Power: 2-wheeler
0.00
50.00
100.00
150.00
200.00
250.00
20 25 30 35 40 45 50 55 60 65 70 75 80 85 90
velocity (kmph)
Force
(N)
Force for a 2-wheeler with 20 sec pick-up
Fa
Fd
Frr
Fg
= 1.2 kg/m3, CD = 0.9, A= 0.5 sqm, = 0.013, weight = 180 Kg, Gradient of 5°
0.00
500.00
1000.00
1500.00
2000.00
2500.00
3000.00
3500.00
4000.00
4500.00
20 25 30 35 40 45 50 55 60 65 70 75 80 85 90
velocity (kmph)
Powe
(W)
Power (W) vs velocity (kmph)
Pa
Pd
Pg
Prr
Chapter 2.0 Vehicle Dynamics 45
46. 4W Compact Sedan: Force and Power
0.00
200.00
400.00
600.00
800.00
1000.00
1200.00
1400.00
1600.00
10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90
velocity (kmph)
Force
(N)
Force for a small Car with 20 sec pickup
Fa
Fd
Frr
Fg
0.00
2000.00
4000.00
6000.00
8000.00
10000.00
12000.00
14000.00
16000.00
18000.00
20000.00
10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90
velocity (kmph)
Power
(Watts)
Power for a small car
Pa
Pd
Pg
Prr
= 1.2 kg/m3, CD = 0.35, A= 2.5 sqm, = 0.013, weight = 1200 Kg, Gradient of 5°
48. Drive Cycle
How much energy will a vehicle take per km?
◦ Concept of Energy-efficiency of a vehicle: Wh/km
◦ Depends upon how the vehicle travels and how much energy it takes
◦ Energy required will depend upon Speed, Acceleration, idling, Deceleration
Definition of a Drive-cycle
◦ A definition of how the vehicle is typically driven
◦ Vehicles tested as per a Standard Drive-cycle, against which its performance is measured
and compared for similar vehicles
◦ How long it travels at what speed and how long and when it is accelerated decelerated?
49. Standard Drive Cycle
A drive cycle is standardised, so that different vehicles can be tested and
compared
◦ Each vehicle type (two-wheeler / small car / bus) may have its own drive-cycle
◦ Each city / town may have its own drive-cycle
◦ Usually climbing a slope and coming down a slope not a part of drive-cycle
◦ A hill-terrain drive cycle should include it: their own drive-cycles
Different countries have different drive-cycles, based on how the vehicles are
driven in the country
Drive-cycle defined for a limited time: tests repeat this several times
◦ Measurements taken over multiple cycles
50. Future: Technology tasks to be pursued
◦ Efficient Regeneration: recovers energy
during deceleration, braking, descending
◦ mechanical energy converted to electrical
energy, to be driven back to battery
◦ Needs motor design to recover as much
energy as possible
◦ Can regeneration efficiency come close
to 90%?
◦ Vehicles will then only use energy to
overcome rolling-resistance and
aerodynamic drag
◦ Materials for light-weighting vehicles
◦ Materials for better insulation to reduce heat-load
◦ air-conditioning competes with drive train for
battery-power
◦ Better tyres and better aerodynamics enhances
energy-efficiency of EVs
◦ Vehicle Controller and Software, Integration and
testing
◦ Can we gainfully redesign every part of IC engine
vehicle as it changes to Electric?
51. To Conclude
Time is of essence: In four years, may be flooded with imported EVs / subsystems
We have two years time to design and manufacture EV subsystems
◦ What can be done in first year, second year and third year?
◦ Not JUST development, but commercialise and SCALE
◦ What does Start-ups and R&D personnel in educational Institutes/ R&D centers have to do?
◦ How do industry-academia work together? What do we need from the Government?
Can we do it by 2030: Certainly
EV article in recent IEEE Electrification Magazine:
https://ieeexplore.ieee.org/document/8546812
For deeper understanding, look at the blog “understanding the EV Elephant”:
https://electric-vehicles-in-india.blogspot.com/2017/12/
52. References
Chapter 1.0 Fundamentals of Electric Vehicles: Technology & economics 52
IEEE Electrification Magazine: https://ieeexplore.ieee.org/document/8546812
Blog “understanding the EV Elephant”:
http://electric-vehicles-in-india.blogspot.com/
WRI-CBEEV Report: 'AGuidance Document onAccelerating Electric
Mobility in India'
NITIAayog Report: Zero Emission Vehicle(ZEV): Towards a policy
Framework