ELEMENTS OF ELECTRICAL ENGINEERING

A PRESENTATION ON :-

BATTERIESAnd

FUEL CELLS

PREPARED BY :-

SHINDE ROHIT

PRESENTATION’S CONTENT :-

Batteries The Battery Connecting battery in series How a battery works? Disposable and Rechargeable Batteries The lead Acid Battery Tha Disposable Battery

Fuel Cells Fuel cells How they works? About Fuel cells Fuel Cells to

Replace Batteries Why Fuel Cells so Uncommon

BATTERY A cell consists of two

electrodes of different metals immersed in a weak acid

Multiple cells can be stacked in series to make a battery

The positive terminal is called the anode and the negative terminal the cathode

CONNECTING BATTERIES IN SERIES Batteries connected

end to end will have a voltage equal to the total voltage of the individual batteries

Disposable dry cell batteries have a typical voltage of 1.5 V

++

+

1.5 V 3 V

HOW A BATTERY (CELL) WORKS Both electrodes slowly

dissolve in the acid At the anode, electrons are

used in chemical reactions as the metal dissolves

At the cathode, electrons are absorbed into the electrode as the metal dissolves

The net result is a buildup of electrons at the cathode

DISPOSABLE AND RECHARGEABLE BATTERIES A rechargeable battery can be connected to

an electric current so that dissolved metals reform on the electrodes

Examples: lead acid, nickel cadmium, lithium, etc.

The chemical reactions that power a disposable battery cannot be reversed

Examples: alkaline dry cells, etc.

THE LEAD ACID BATTERY Two electrodes, one of

lead, the other of lead dioxide (PbO2) immersed in sulfuric acid

Lead ions (Pb++) dissolve, leaving two electrons behind

Two electrons flow through the circuit and are used to help lead dioxide dissolve

DISPOSABLE BATTERIES A typical disposable

battery contains a carbon (graphite) and a zinc electrode

The electrolyte is a paste of ammonium chloride

Disposable batteries may leak if too much of the zinc can is dissolved

FUEL CELLS In a fuel cell hydrogen

is “burned” by mixing with oxygen in such a way that it creates a voltage across two electrodes

Only water is produced as a by-product

Hydrogen can be fed in directly or as part of larger molecules such as methane (natural gas)

HOW THEY WORK ? Hydrogen molecules

give up their electrons to the first electrode

Electrons pass through the circuit to the second electrode

Electrons are returned to the molecules when hydrogen and oxygen combine to make water

ABOUT FUEL CELLS Fuel cells have been around for 100 years Fuel cells can be made to burn other

molecules, such as methane, propane, etc. Hydrogen can be extracted from gasoline

before being fed into a fuel cell Fuel cells cannot store energy, so they must

be used in conjunction with a storage battery

FUEL CELLS TO REPLACE BATTERIES Fuel cells can be used

to power a laptop Micro fuel cells have

been developed that are small enough to fit into a cell phone

Fuel cells weigh less and last much longer than rechargeable batteries

WHY ARE FUEL CELLS SO UNCOMMON? Methods are being developed to store

hydrogen in a porous material rather than as compressed gas

Fuel cells require expensive catalysts How do you pump compressed hydrogen at a

self-service gas station? What happens to the hydrogen tank in an

accident?

THANK YOU……