The document discusses the advancements and significance of lithium-ion batteries in electric vehicles (EVs) and hybrid electric vehicles (HEVs), highlighting their environmental benefits and market potential with sales reaching $80 billion annually. It examines various battery technologies, including lead-acid, nickel-metal hydride, and lithium-polymer, while addressing regenerative braking and battery management systems that enhance vehicle efficiency. The report concludes that ongoing technological improvements are making hybrid cars increasingly viable as sustainable transportation alternatives.

1. Batteries For EVs and HEVs
Name: Satyajeet Udavant
Course: Energy Storage and Devices
IUPUI, INDIANAPOLIS

2. Abstract:
Lithium ion batteries are a great success to grow to become a leader in the battery
industry. Battery Sales is reaching $80‐billion annually. This report discusses a brief
history of the batteries for EVs and HEVs. It discusses why and how Battery powered EVs
and HEVs could become a reality. New advances in technologies like regenerative
breaking, mass production that reduces cost, battery management system, and higher
battery life and battery efficiency are the few of the techies that made this possible, at
length in the following report.
Introduction:
Environmental impact of traditional mode of transport -Our personal and luxury vehicles
are a major reason to global warming. Together, cars and trucks account for almost one-
fifth of all U.S. emissions, emitting more than 25 pounds of carbon dioxide, NOx, CFCs
and other global-warming gases for every gallon of gas. Almost 6-7 pounds comes from
various process of extraction, production, and delivery of the fuel, while the biggest of
all is of heat-trapping emissions which accounts more than 19 pounds per gallon it
comes from cars. Increasing number of cars used and with advancing technologies
substitute for traditional way of transport was necessary. As the following figure
suggest;
As you can see the graph is getting more steep with growing demand of the cars.
Need of Electric Vehicles and Hybrid Electric vehicles:

3. Electric Vehicles (EVs) are considered “zero emission” as they don’t release harmful
gases. They are said to be free from greenhouse gases or other pollutants and harmful
chemicals during usage.
“Based on electricity rates in 50 cities across the United States, the analysis found
drivers can save $750 to $1,200 dollars a year compared to operating an average new
compact gasoline vehicle (27 mpg) fueled with gasoline at $3.50 per gallon. Higher gas
prices would mean even greater EV fuel cost savings. For each 50 cent increase in gas
prices, an EV driver can expect save an extra $200 a year.”[1]
Comparison Table:
Characteristics Lead Acid Li-polymer
Specific energy 33–42 Wh/kg 100–265 W·h/kg
Energy density 60–110 Wh/L 250–676 W·h/L
Specific power 180 W/kg ~250-~340 W/kg
Charge/discharge
efficiency
50–95% 80–90%
Energy/consumer-
price
7(sld)to 18(fld) Wh/US$ 2.5 W·h/US$
Self-discharge rate 3–20%/month 31% at 60 °C
Cycle durability 500–800 cycles
400–1200 cycles
Nominal cell voltage 2.0 V 3.6 / 3.8 V
Charge temperature
interval
min. −35 °C, max. 45 °C
1. Description of the project Provide some basic information on the topic such as the
working principles, structure, composition, etc. Background information.
What has been done for this topic, advantages and disadvantages of the current
work/approaches, what is the state-of-art of this topic? What is the problem?

4. Various Technology Advances:
Regenerative breaking.
In electric and hybrid cars, the regenerative brakes can do an amazing function, it can
charge the main battery pack, and therefore, it effectively extends the vehicle's range
between successive charges.
Most of the vehicles now use bulks of supercapacitors or ultracapacitors for storing
energy instead of batteries. The reason being supercapacitors can store energy more
quickly and can discharge it quickly. It is also better in storing large amount of energy.
The only disadvantage is that it can store it for long time. Also the wear and tear causes
more maintenance.
Working[2] : When you're driving along, energy flows from the batteries to the motors,
turning the wheels and providing you with the kinetic energy you need to move. When
you stop and hit the brakes, the whole process goes into reverse: electronic circuits cut
the power to the motors.
Now, your kinetic energy and momentum makes the wheels turn the motors, so the
motors work like generators and start producing electricity instead of consuming it.
Power flows back from these motor-generators to the batteries, charging them up.
Graphs talks about the comparison between the kinetic energy and the power to and
from the battery

5. Idle speed :Start-Stop
In Urban areas due to heavy traffic cars are constantly under start and stop condition.
For conventional cars it uses the gasoline and due to less requirement of power a lot of
fuel is wasted. In hybrid and complete electric cars the powertrain is modified as per the
different driving conditions like in urban drive, the gasoline engine remains dormant
while at rest. Whenever cars come to a halt in traffic or signal scenarios the engine is
shut. Next time when the drive requires power to start it draws this power from the
battery .Battery technology has made cars more fuel efficient. Battery management
system deals with the management of the charge and discharge of the battery, heat
dissipation and temperatures effects are all countered and efficiency is increased.[5]

6. Above fig talks about the Start-stop Engine technology, Ideal for Urban areas where cars
are frequently run and stopped at signals.
Types of Battery
1.) Lead–Acid battery
It has very low energy-to-weight ratio and a low energy-to-volume ratio, power-to-weight
ratio is the ability to supply high surge currents.
Negative plate reaction:
Pb(s) + HSO− 4(aq) → PbSO 4(s) + H+ (aq) + 2e−
Positive plate reaction:
PbO 2(s) + HSO− 4(aq) + 3H+(aq) + 2e−
→ PbSO4(s) + 2H2O(l)
The total reaction can be written as
Pb(s) + PbO2(s) + 2H2SO 4(aq) → 2PbSO4(s) + 2H 2O(l)
The sum of the molecular masses of the reactants is 642.6 g/mol, so theoretically a cell
can produce two faradays of charge (192,971 coulombs) from 642.6 g of reactants, or
83.4 ampere-hours per kilogram (or 13.9 ampere-hours per kilogram for a 12-volt
battery)For a 2 volts cell, this comes to 167 watt-hours per kilogram of reactants, but a
lead–acid cell in practice gives only 30–40 watt-hours per kilogram of battery, due to the
mass of the water and other constituent parts.[3]

7. Application:
It is used in motor vehicles to provide the high current required by automobile starter
motors.
Risk:
Excessive charging causes electrolysis, it results in gassing. Process of emitting
hydrogen and oxygen is known as "gassing’’.
Also corrosion on the positive terminal is caused by electrolysis, this happens because
of the existant mismatch of metal alloys that are used in the manufacture of the battery
terminal.
2.) Nickel Metal Hydride battery
The NiMH battery is termed an alkaline storage battery due to the use of
potassium hydroxide (KOH) as the electrolyte. Electrically, NiMH batteries are
very similar to nickel cadmium batteries. Rechargeable alkaline storage batteries
are a dominant factor in the market for several technically important reasons:
High electrolyte conductivity allows for high power applications
The battery system can be sealed, minimizing maintenance and leakage issues
Operation is possible over a wide temperature range
Long life characteristics offset higher initial cost than some other technologies
Higher energy density and lower cost per watt or watt-hour (depending on
design)

8. 3.) Li-ion battery:
The cathode
The anode
The overall reaction
Overdischarge supersaturates lithium cobalt oxide, leading to the production of lithium
oxide possibly by the following irreversible reaction:
[4]
Disadvantage:
However, one downside to lithium-ion batteries is that they require longer to charge
than other batteries. But there is always room for improving the efficiency

9. 4.)Lithium Polymer Battery:
It has most advantages of that of the lithium ion battery. The solid polymer is
transparent to Li+ and opaque to electrons. This gives safety by giving a battery more
resistant to overcharge. Less chance to spill the electrolyte. Flexibility in shape and size
as thin strips or sheets are used. Therefore creating light weight cell.
Disadvantages: It has low ionic conductivity.
Few others:
Zinc Air Battery:
Sodium Metal Chloride Battery
Nickel Cadmium Battery:
Discussions:
Maintenance:
Hybrids have the components of a regular gas engine along with their electric aspects,
they do require the same routine maintenance as any other gas vehicle.
One of the biggest attacks made on hybrids has to do with battery life. It is said that the
battery life is very short, and if something were to happen to it, it is very expensive to
replace
Need of skilled labors to work on advanced systems that these cars possessed.
Fire hazards from overheating the battery

10. 2. Conclusion
With the advances in technology hybrid cars are becoming a reality.
Regenerative breaking
Engine idle- start stop
Downsizing of the car components
Different battery types and the increased efficiency due to low consumption of fuel
Reference:
[1] http://www.ucsusa.org/clean-vehicles/electric-vehicles/emissions-and-
charging-costs-electric-cars#.Vxh_2DFu32I
[2] http://www.explainthatstuff.com/how-regenerative-brakes-work.html
[3] 3.014 MATERIALS LABORATORY MODULE – BETA 1
NOVEMBER 13 – 17, 2006 GEETHA P. BERERA LEAD-ACID STORAGE CELL

11. [4] Thin, Flexible Secondary Li-Ion Paper Batteries
Liangbing Hu,† Hui Wu,† Fabio La Mantia, Yuan Yang, and Yi Cui*
Department of Materials Science and Engineering, Stanford University, Stanford,
California 94305
[5] An Intelligent Regenerative Braking Strategy for Electric Vehicles
Guoqing Xu 1,2, Weimin Li 3,*, Kun Xu 3 and Zhibin Song 3