Batteries

Batteries

A cell also known as Storage cell.

·         A cell is a source of D.C in which Chemical Energy is converted into  Electrical Energy.

• ·         A group of such cells either connected in either series or parallel or series – parallel is known as Battery.
• ·         This process is called Electro Chemical action. A cell consists of two dissimilar metal plates ( Say Copper and Zinc) immersed in an electrolyte .
• ·         The chemical action in the cell causes copper plate to become Positively charged and Zinc plate Negatively charged.
• ·         If plates of Zinc and lead are placed in a solution of H₂SO_4, the emf developed  is about 0.5 Volts . Zinc and Copper in H₂SO₄ about 1.1 Volts.
• ·         The E.M.F of a cell does not depend upon the size and spacing between the plates.
• ·         With the increase in the size of the plates the capacity of the cell increases i.e the cell will deliver current for the longer period.

can be broadly classified as

1. Primary Cells       2. Secondary Cells

Primary Cell is a cell in which chemical action is not reversible.

Ø  A primary cell is one in which the chemical action eats away one of the electrodes, usually Negative electrode.

Ø  Many types of primary cells have been developed

Ø  Primary Cells are also called “Disposable Cells” or “Throw away” Cells.

Examples  Voltaic Cell , Daniel Cell (Wet Cell), Leclanche Cell (Carbon –Zinc Cell), Dry Cell ,

Zinc Chloride Cell (Heavy Duty Cell), Lithium Cell ,Zinc-Mercuric Oxide cell ,Zinc-Silver Oxide cell

 Secondary Cell is one in which Chemical action is reversible.

Ø  Secondary cells are also known as accumulators or rechargeable batteries sometimes storage batteries.

Ø  There is no actual consumption of any plate and that the chemical process is reversible.

Ø  Secondary cell first invented by the French Scientist Gaston Plante in 1859. When a current is passed  through a solution, a chemical reaction starts.

Ø  Due to this chemical reaction an electro Motive Force (emf) is developed in the cell. This emf is called Back Electro motive force.

Ø  When electrical energy is sent an electro motive force is developed between the cells due to their taking part in chemical reactions  and energy sent is stored up in the chemical energy form.

Ø  Chemical energy will be converted into Electrical energy when cell connected to load.

Examples of Secondary Cells

Ø   Lead acid Battery , Nickel – Iron alkaline Battery ( Edison Cell) , Nickel – Cadmium alkaline Battery  Silver – Zinc Batteries