The document provides an overview of lead acid batteries, detailing their construction, working principle, active materials, charging and discharging processes, maintenance, applications, advantages, and disadvantages. It describes the chemical reactions involved during both charging and discharging, as well as practical maintenance tips and uses in various applications. Lead acid batteries are characterized by their ability to produce high currents, affordability, but also have limitations such as low specific energy and environmental concerns.

1. MBM UNIVERSITY (JODHPUR) RAJASTHAN
B.E. 2YEAR A1 (2022)
MECHANICAL ENGINEERING
PRESENTED BY:
ASHISH SAINI

2.  The battery which uses sponge
lead and lead peroxide for the
conversion of the chemical
energy into electrical power,
such type of battery is called a
lead battery
WHAT IS LEAD ACID BATTERY

3. LEAD ACID BATTERY : CONSTRUCTION

4.  A Lead acid battery consistes of plates ,separator,and electrolyte ,hard
plastics with a hard rubber case.
 In Lead acid batteries ,the plates are of two type ,positive and negative .
 The positive plate consists of lead dioxide and negative plate consistes of
sponge lead.
 The plates are separated by a separator which is an insulating material
 This total construction is kept in hard plastics case with an
electrolyte ,which is water and sulfuric acid

5. ACTIVE MATERIAL UESD IN LEAD
ACID BATTERY
1. LEAD PEROXIDE (PbO2) - it forms the positive active material .the PbO2 are dark
chocolate broom in colour.
2. SPONGE LEAD - its form the negative active material .it is grey in colour.
3. DILUTE SULFURIC ACID (H2SO4) - it is used as an electrolyte .it contains 31% of
sulfuric acid.
The material in a cell which takes active
participation in a chemical reaction during
charging or discharging is called the active
material of the cell.

6. LEAD ACID BATTERTY :WORKING

7.  The sulfuric acid dissolves ,its molecules break up into positive
hydrogen ions (2H+) and sulphate negative ions (S04-) and move freely.
 now two electrodes are immersed in solutions and connected to dc
supply the positive charge H+ ions moves towards electrode and
connected negative terminal(cathode), also SO4- ions connected positive
terminal(anode).
 Each hydrogen ion take one electron from cathode and sulphate ion take
two negative ions from anode and react with water and form sulfuric and
hydrogen acid.
 The oxygen ,which produced from the above equation react with lead
oxide and form lead peroxide , during charging the lead cathode remains
as lead while lead anode get converted into lead peroxide ,chocolate in
colour.
CHEMICAL ACTION DURING CHARGING

8. CHEMICAL ACTION DURING DISCHARGING
 Discharging cell, is full discharge then anode is lead peroxide(PbO2) and
cathode is metallic sponge lead(Pb).when the electrode connected through a
resistance ,the cell discharge and electron flow opposite direction.
 the hydrogen ions moves towards anode and reaching the anodes receive
one electron from the anode and become hydrogen atom.
 the hydrogen atom comes in contacts with a PbO2,so it attacks and form
PbSO4,that is whitish colour.
 PbSO4 + 2H = PbO +H2O
PbO + H2SO4 = PbSO4 +2H2O
_______________________________
PbO2 + H2SO4 +2H = PbSO4 +2H2O
 The each SO4- ion moves towards the cathode and reaching gives up two
electrons becomes radical SO4, attack the metallic lead cathode and form
lead sulphate whitish in colour according to the chemical equation.

9. CHEMICAL ACTION DURING RECHARGING
 The lead storage cell can be recharged by passing a current in
the reverse dirction.
 the half reactions are the exact reverse of those that occure
when the cell is operating as a voltaic cell.
 In lead storage battery we have,
PbSO4 +2H = H2SO4 + Pb
 IN figure ,the downward arrow indicates discharge and an
upward arrow indicates the recharge process

10. MAINTENANCE OF LEAD ACID BATTERY
1) Battery can be stored in a well – ventilated room.
2) Keep terminals corrosion free and well tightened.
3) Frequenting recharging the battery even it is not in use.
4) Topping up with water when low.
APPLICATION OF LEAD ACID BATTERY
 It is used motor vehicles- to power engine starter motor.
 it is used in solar panel energy storage for night use.
 It is used electric power diesel generators starting system.
 Mobile equipment that can not be connected to grid power e.g. entertainment and media
automobiles.

11. DISADVANTAGES OF LEAD ACID BATTERY
 It is low specific energy
 It is taking time for full charging about 14-16 hours.
 It is limited cycle life ; repeated deep –cycling reduces battery life .
 It is not environmentally friendly.
ADVANTAGES OF LEAD ACID BATTERY
 It is able to produce high current
 It is low voltage rating .
 It is available and affordable in different sizes.
 It is low expensive and simple to manufacture ;low cost per watt –hour.
 It is good performancs at low and high temperature.

12. THANK YOU