This document discusses different types of electrochemical cells and batteries. It describes the construction and working of common battery types like lead-acid, nickel-cadmium and lithium-ion batteries. Fuel cells are also introduced as electrochemical cells that convert chemical energy of fuels like hydrogen directly into electricity. Specific fuel cell types like Bischoff cell and hydrogen-oxygen fuel cell are explained. The document concludes by discussing applications of fuel cells in the automobile industry to power electric vehicles.

1. Cells and Batteries
D.MaruthamaniD.Maruthamani
Assistant ProfessorAssistant Professor
Department of ChemistryDepartment of Chemistry
PSG College of TechnologyPSG College of Technology
Coimbatore – 641 004Coimbatore – 641 004
Electrochemical power sourcesElectrochemical power sources

2. Cells and Batteries
Types of electrochemical cells

3. Cells and Batteries
Batteries
• Battery is a device consisting of a series of galvanic
cells that can act as portable source of direct electric
current at a constant voltage.
• Used in calculators, watches, pace makers for heart,
hearing aids, computers, car engines, stand-by power
supplies, emergency lighting in hospitals,
electroplating, industrial traction and military and
space applications.
• The size of batteries ranges from a fraction of a cubic
centimetre to several cubic decimetres.

4. Cells and Batteries
Factors influencing the emf of batteries
According to Nernst equation at 298K
• The emf of a battery largely depends on
As the difference in the electrode potential
increases the emf also increases for a given value of
Q at constant temperature.
• Temperature and the concentration ratio given by
reaction quotient Q.

5. Cells and Batteries
Leclanche cell
• Invented by the French engineer
George Leclanche in about 1886.
• Dry cell, contains the elctrolyte in the
form of a thick paste.
• Not rechargeable.

6. Cells and Batteries
Construction of Leclanche cell

7. Cells and Batteries
Working of Leclanche cell

8. Cells and Batteries
Limitations of Leclanche cell
• Not designed for heavy current outputs. Withdrawal
about 25 to 50mA will increase the efficiency and life
of battery.
• Not designed for continuous use. Intermittent usage
will increase the efficiency of battery.
• When not in use for a long period, the batteries
should be removed from the device and should be
stored in a cool place. Otherwise, condensation can
cause electrical leakage which reduces life and may
destroy the battery case.

9. Cells and Batteries
Lead-acid battery
• Invented by the French physicist
Gaston Plante in the year 1893.
• Rechargeable.

10. Cells and Batteries
Construction of lead-acid battery

11. Cells and Batteries
Construction of lead-acid battery (cont....)

12. Cells and Batteries
Working of lead-acid battery

13. Cells and Batteries
Working of Lead-acid battery (cont….)
Discharging reactions
Anode reaction:
Cathode reaction:

14. Cells and Batteries
Working of Lead-acid battery (cont….)
Recharging reactions
Anode reaction:
Cathode reaction:

15. Cells and Batteries
Limitations of Lead acid battery
• More amounts of materials should be taken. Because,
the products lead sulphate and water are poor
conductors of electricity. Moreover, acid gets
progressively diluted.
• Optimal charging and discharging should be done to
avoid the loss of efficiency.
• Wrong polarity connection should be avoided.
• Acid concentration and proper connections should be
monitored /checked frequently.

16. Cells and Batteries
Ni-Cd battery
• Invented by the Sweden scientist Waldemar Jungner
in the year 1899.
• Rechargeable battery.
• Nickel-cadmium is the only battery type that
performs well under rigorous working conditions.

17. Cells and Batteries
Construction of Ni-Cd battery
Anode : Cd/CdO Sheets Electrolyte : 22% KOH
Cathode : Nickel hydroxide with 14% Nickel foil

18. Cells and Batteries
Construction of Ni-Cd battery (cont...)

19. Cells and Batteries
Working of Ni-Cd battery
First charging

20. Cells and Batteries
Working of Ni-Cd battery (Cont…)
Discharging

21. Cells and Batteries
Working of Ni-Cd battery (Cont…)
Recharging

22. Cells and Batteries
Applications of Ni-Cd battery
"Eveready" sealed nickel-cadmium batteries are
ideally suited for use in many types of battery-
operated equipment.
Some of the applications are listed here:Some of the applications are listed here:
Calculators Personal Pagers
Dictating machines Digital Cameras
Instruments Radio control
Radios Photoflash equipment
Portable computers Tape recorders
Television sets
Portable hand tools and appliances
Cassette players and recorders
Portable communications equipment

23. Cells and Batteries
Fuel cells
Fuel cells are electrochemical cells in which the
chemical energy of easily available fuel such as
hydrogen, methane etc. is converted into electrical
energy by their oxidation at suitable anodes.

24. Cells and Batteries
Bischoff cell
Construction:
• Fuel (here carbon) acts as anode.
• Wire gauze makes electrical connection with fuel
bed.
• Oxygen electrode (set up by circulating oxygen
continuously through bed of granular magnetite)
acts as cathode.
• Sodium carbonate acts as electrolyte.

25. Cells and Batteries
Construction of Bischoff cell

26. Cells and Batteries
Working of Bischoff cell
Anode:
The carbon ions ( ) generated at anode react with
carbonate ions present in electrolyte to form carbon
dioxide.

27. Cells and Batteries
Working of Bischoff cell (Cont…)
Cathode:
At the cathode oxygen ionizes at the magnetite surface
to form oxygen ions.

28. Cells and Batteries
Working of Bischoff cell (Cont…)
Since the clay support for the electrolyte is thin and
porous, sodium oxide and carbon dioxide readily come
into contact and in doing so react to regenerate the
ionized electrolyte.
Overall reaction

29. Cells and Batteries
Bacon Hydrogen-Oxygen fuel cell

30. Cells and Batteries
Working of Hydrogen-Oxygen fuel cell
• Oxygen diffuses into the cell through a porous
carbon electrode containing silver as catalyst.
• Hydrogen diffuses into the cell through a similar
porous carbon electrode containing nickel or
platinum as catalyst.
• The electrolyte, a warm solution of KOH, is
placed between the two electrodes.

31. Cells and Batteries
Different Hydrogen-Oxygen fuel cells

32. Cells and Batteries
Different Hydrogen-Oxygen fuel cells

33. Cells and Batteries
Applications in automobile industry

34. Cells and Batteries
Applications in automobile industry

35. Cells and Batteries
Applications in automobile industry

36. Cells and Batteries
Applications in automobile industry

37. Cells and Batteries
Applications in automobile industry
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