The document discusses the key components and working of automotive batteries. It provides details on: 1) The typical composition of lead-acid batteries used in most vehicles, including lead plates, sulfuric acid electrolyte, and plastic casing. 2) The electrochemical reactions that occur during charging and discharging, allowing the battery to store and provide electrical energy. 3) The various functions of the battery, including starting the engine using high current and powering electrical components when the engine is off. 4) Common types of batteries like lead-acid, lithium-ion, and nickel-metal hydride, along with their characteristics.

1. Battery
Bhushan M. Nasre
L-30
Mechanical Engineering
Reg no. - 23070120

2. Introduction
An automotive battery is a rechargeable
energy storage device that provides electrical
power to start the engine and power various
electrical systems in a motor vehicle when the
engine is not running. It plays a crucial role in
the vehicle's electrical system by supplying
the initial power needed to start the engine
and by providing a stable source of electrical
energy for lights, electronics, and other
components when the engine is off.

3. Key Features Of Battery
1. Voltage: Automotive batteries typically provide 12 volts of electrical potential. This voltage is used to power the vehicle's
electrical systems and accessories.
2. Capacity: Capacity is measured in ampere-hours (Ah) and represents the amount of electrical energy the battery can
store. It determines how long the battery can supply a specific level of current.
3. Cranking Amps (CA) and Cold Cranking Amps (CCA): These ratings indicate the ability of the battery to deliver a
high current for starting the engine. Cold Cranking Amps (CCA) is particularly important in cold weather conditions.
4. Terminals: Automotive batteries have terminals for connecting electrical cables. The positive terminal is usually marked
with a "+" symbol, while the negative terminal is marked with a "-" symbol.
5. Construction: Lead-acid batteries consist of lead dioxide (positive plate), sponge lead (negative plate), and a sulfuric
acid electrolyte. The battery is typically housed in a plastic casing.
6. Maintenance: Traditional lead-acid batteries may require periodic maintenance, including checking and topping up
electrolyte levels with distilled water. However, maintenance-free batteries, such as Absorbent Glass Mat (AGM) and
Gel Cell batteries, are becoming more common.
7. Charging System: The vehicle's charging system, typically composed of an alternator, recharges the automotive
battery while the engine is running. This ensures that the battery remains charged and ready for the next start.

4. Principle of
Working
Car batteries convert chemical
energy to electrical energy via a
lead-acid reaction in sulfuric acid.
Discharging powers, the vehicle,
while charging reverses the
reaction for energy storage. This
process is crucial for supplying
electrical power to a car's systems.

6. Working Of Battery
The automotive battery is a critical component in a vehicle's electrical system, providing the
necessary electrical energy to start the engine and power various electrical components when the
engine is not running.
1. Composition:
- Automotive batteries are typically lead-acid batteries, which consist of lead dioxide (positive
plate), sponge lead (negative plate), and a sulfuric acid electrolyte.
2. Electrochemical Reaction:
- When the battery is connected to the vehicle's electrical system, a chemical reaction occurs
between the lead dioxide and sponge lead plates in the presence of the sulfuric acid electrolyte.
- This chemical reaction results in the generation of electrical energy.
3. Voltage Production:
- The electrochemical reaction produces voltage, and a typical automotive battery is designed to
provide around 12 volts. This voltage is used to power the vehicle's electrical components.
4. Starting the Engine:
- The primary function of the automotive battery is to provide the high current needed to start the
vehicle's engine. When the ignition key is turned, the battery sends electrical energy to the starter
motor, which cranks the engine.
5. Powering Electrical Components:
- When the engine is not running, the battery continues to power various electrical components
in the vehicle, such as lights, radio, air conditioning, and electronic systems.
6. Charging System:
- When the engine is running, the alternator, driven by the engine's crankshaft, generates
electrical energy. This energy is used to recharge the battery and power the vehicle's electrical
system.
- The alternator also maintains the battery's charge and ensures a continuous supply of electrical
power.
7. Chemical Reactions:
- During the charging process, the electrochemical reactions in the battery are reversed. The lead
sulfate formed during discharge is converted back into lead dioxide and sponge lead.
8. Electrolyte Level:
- The battery has a liquid electrolyte (sulfuric acid and water). Over time, due to chemical
reactions and evaporation, the electrolyte level may decrease. Periodic maintenance involves
checking and topping up the electrolyte with distilled water.
9. CCA (Cold Cranking Amps):
- The Cold Cranking Amps rating of a battery indicates its ability to deliver a high current at low
temperatures, which is crucial for starting the engine in cold weather.
10. Battery Life:
- The lifespan of an automotive battery depends on factors such as usage, charging system
efficiency, temperature conditions, and maintenance. Batteries typically last several years but may
need replacement when their performance declines.

7. Types of
Battery
1. Lead-Acid Batteries:
- Type: Wet-cell battery.
- Composition: Lead-acid batteries have lead dioxide
(positive plate), sponge lead (negative plate), and a sulfuric
acid electrolyte.
- Applications: Used in most conventional internal
combustion engine vehicles.
- Variants:
- Flooded Lead-Acid (FLA): Electrolyte is in liquid form.
- Absorbent Glass Mat (AGM): Electrolyte is absorbed in
a fiberglass mat.
- Gel Cell: Electrolyte is in gel form.
2. Lithium-Ion Batteries:
- Type: Dry-cell battery.
- Composition: Lithium-ion batteries use lithium ions as
the charge carriers.
- Applications: Increasingly used in hybrid and electric
vehicles (HEVs and EVs).
- Advantages: Lighter, longer lifespan, higher energy
density, and faster charging compared to traditional lead-
acid batteries.
- Disadvantages: Higher cost and sensitivity to
temperature extremes.
3. Nickel-Metal Hydride (NiMH) Batteries:
- Type: Dry-cell battery.
- Composition: Nickel-metal hydride batteries use nickel
oxyhydroxide as the positive electrode and a hydrogen-
absorbing alloy as the negative electrode.
- Applications: Commonly found in hybrid vehicles,
including early models like the Toyota Prius.
- Advantages: Good energy density, reliable, and less
expensive than lithium-ion batteries.
- Disadvantages: Slightly lower energy density than
lithium-ion batteries.
4. Lead-Carbon Batteries:
- Type: Wet-cell battery.
- Composition: Lead-carbon batteries combine lead-acid
technology with carbon additives in the negative
electrode.
- Applications: Used in some advanced start-stop systems
and energy storage applications.
- Advantages: Improved charge acceptance, longer cycle
life, and better performance in partial state of charge
conditions compared to traditional lead-acid batteries.
5. Valve-Regulated Lead-Acid (VRLA) Batteries:
- Type: Wet-cell battery.
- Composition: Similar to traditional lead-acid batteries
but designed to be maintenance-free with a regulated
valve to control gas release.
- Applications: Commonly used in motorcycles, ATVs, and
other small vehicles.
- Advantages: Sealed construction, reduced maintenance,
and versatile mounting options.
6. Zinc-Air Batteries:
- Type: Dry-cell battery.
- Composition: Zinc-air batteries use zinc as the anode
and air as the cathode.
- Applications: Emerging technology with potential
applications in electric vehicles and portable electronics.
- Advantages: High energy density, environmentally
friendly.
- Challenges: Limited cycle life and challenges related to
the availability of oxygen from the air.

8. Materials Used in Battery
1. Lead:
- Usage: Lead is a fundamental component used in both the
positive and negative plates of lead-acid batteries.
- Role: In the positive plate, lead dioxide (PbO2) is formed during
charging, while in the negative plate, sponge lead (Pb) is formed.
2. Sulfuric Acid (Electrolyte):
- Usage: Sulfuric acid is used as the electrolyte in lead-acid
batteries.
- Role: It facilitates the electrochemical reactions between the
lead dioxide and sponge lead plates, allowing the flow of electrical
current.
3. Plastic (Polypropylene or ABS):
- Usage: The battery casing is typically made of plastic, such as
polypropylene or acrylonitrile butadiene styrene (ABS).
- Role: It serves as a durable, lightweight, and chemical-resistant
container, holding the lead plates and sulfuric acid while preventing
leaks.
4. Lead Dioxide (PbO2):
- Usage: Lead dioxide is formed on the positive plate during the
discharge (when the battery is providing electrical power).
- Role: It participates in the electrochemical reactions, facilitating
the release of electrons.
5. Sponge Lead (Pb):
- Usage: Sponge lead is formed on the negative plate during
discharge.
- Role: It participates in the electrochemical reactions, facilitating
the absorption of electrons.
6. Separator (usually made of microporous PVC):
- Usage: Separators are placed between the positive and
negative plates to prevent short circuits while allowing the flow of
ions.
- Role: The separator helps maintain the necessary electrical
isolation between the plates.
7. Brass or Lead-Calcium Alloy (for battery terminals):
- Usage: Battery terminals are typically made of brass or lead-
calcium alloy.
- Role: These materials provide a stable connection point for
electrical connections to the vehicle's electrical system.
8. Glass Mat (for Absorbent Glass Mat - AGM batteries):
- Usage: AGM batteries use a glass mat to absorb and immobilize
the electrolyte.
- Role: The glass mat design enhances the battery's efficiency,
vibration resistance, and maintenance-free characteristics.

9. Manufacturing
Process
Involved in
Battery
1. Plate Manufacturing:
- Positive Plate: Lead dioxide (PbO2) paste is applied to
a lead grid, and the plate is cured to form the positive
plate.
- Negative Plate: A paste of sponge lead (Pb) is applied
to a lead grid, and the plate is cured to form the negative
plate.
2. Separator Manufacturing:
- Separators, often made of microporous PVC, are
manufactured to the required specifications.
3. Battery Case Manufacturing:
- Plastic cases, typically made of polypropylene or ABS,
are injection molded to form the outer casing of the
battery.
4. Assembly:
- Positive and negative plates, along with separators, are
assembled in a specific sequence to create the internal
structure of the battery.
- The battery case is filled with sulfuric acid electrolyte.
5. Formation:
- The battery undergoes a formation process, where it is
subjected to controlled charging and discharging cycles.
This process activates the chemical reactions in the plates
and optimizes the battery's performance.
6. Sealing:
- The battery is sealed to prevent leakage and to contain
the sulfuric acid electrolyte.
7. Terminal Attachment:
- Battery terminals, usually made of brass or lead-calcium
alloy, are attached to the battery to provide connection
points for electrical cables.
8. Quality Control:
- The manufactured batteries undergo rigorous quality
control checks to ensure that they meet specified
performance and safety standards.
9. Labelling and Marking:
- The batteries are labelled with important information,
including specifications, safety instructions, and recycling
symbols.
10. Charging and Testing:
- The batteries are charged to the desired state of
charge, and their performance is tested to ensure they
meet electrical and functional requirements.
11. Packaging:
- The final batteries are packaged for shipment.
Packaging materials are chosen to provide protection
during transportation and storage.