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BATTERIES. INTRODUCTION TO BATTERY. A cell or connected group of cells that converts chemical energy into electrical energy by reversible chemical reactions and that may be recharged by passing a current through it in the direction opposite to that of its discharge is called a battery.
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INTRODUCTION TO BATTERY • A cell or connected group of cells that converts chemical energy into electrical energy by reversible chemical reactions and that may be recharged by passing a current through it in the direction opposite to that of its discharge is called a battery. • It is also known as a storage cell.
PRIMARY BATTERY • A primary battery converts chemical energy to electrical energydirectly, using the chemical materials within the cell to start the action.
PROPERTIES • Primary batteries are non-rechargeable. • Any attempt to recharge such batteries might prove hazardous. • The chemical reaction which occurs when the battery is in use is non-reversible. • Examples : Mercury cells, Zinc chloride cells, Zinc carbon cells, etc.
DRY CELL • This type of dry cell or primary cell was first of all prepared by French scientist Leclanche in 1867. • Hence, it is also called Leclanche cell.
Dry cell uses an electrolytic paste which reacts with the electrodes to produce a negative charge on one electrode and a positive charge on the other. • The difference of potential between the two electrodes is the output voltage.
MERCURY BATTERY • A mercury battery is a non-rechargeable electrochemical battery. • Mercury batteries were used in the shape of button cells for watches, hearing aids, and calculators, and in larger forms for other applications.
SECONDARY BATTERY • The secondary battery must first be charged with electrical energy before it can convert chemical energy to electrical energy.
PROPERTIES • Secondary batteries are rechargeable batteries. • When supplied with current from a source, the chemical reaction which occurs when the cell is use, is reversed. • Examples : Lead-acid cells, nickel-cadmium cells, sodium-ion cells, etc.
Lead Acid Battery • In a lead acid battery the reaction of lead and lead oxide with the sulfuric acid electrolyte produces a voltage.
The cell potential of this cell is about 2 volt. • Here, electrodes must be of dissimilar metals. • Electrolyte must be an active electrolyte.
Ni-Cd BATTERY • The nickel–cadmium battery is a type of rechargeable batteryusing nickel oxide hydroxide and metallic cadmiumas electrodes.
Its life is more than that of lead acid battery but its production is very costly. • Used in hazardous environment such as chemical, fertilizer, cement industry.
There are two important ratings for a battery. They are: • Ampere-hour rating • Watt-hour rating
AMPERE-HOUR RATING • It is a function of the total plate area multiplied by the number of plates. • For measuring this capacity, the battery is discharged continuously for 20 hours & its current input supplied to a standard load is measured. • Suppose a battery delivers 4A current for 20 hours, its rating is 80Ah which is stamped on the battery case.
WATT-HOUR RATING • The Watt-hour rating is given by the product of the Ampere-hour rating and the average discharge voltage of the battery. • Suppose the battery supplies 12A for 10 hours. Then its Ah rating is 120Ah. • If the average discharging voltage is 2V then the Watt-hour rating = 120*2 = 240Wh.
PRESENTED BY- • CHAUHAN MIHIR (13BEEEG067) • CHOKSHI MITHIL (13BEEEG069) • MACWAN JOYAS (13BEEEG070) • SHAH RUSHABH (13BEEEF079)