Primary And Secondary Cells Pp.pptx

Primary and Secondary Cells

What is a Battery? • A battery is a device consisting of one or more cells with external connections (also referred to as terminals) provided to power electrical devices such as flashlights, electronics(like smartphones, laptop etc.) and electric cars. • A battery has two terminals positive (referred to as the cathode) and the negative terminal (referred to as the anode). The terminal labelled negative is the source of negative ions (electrons) that while connected to an external circuit will flow and deliver energy to the external device.

What is a Electric Cell? • An electric cell is a device capable of generating electrical energy from chemical reactions. An electric cell consists of two half-cells. Each half-cell consists of an electrode and an electrolyte. • The two half-cells may use the same electrolyte, or they may use different electrolytes. The chemical reactions in the cell may consists of the electrolyte, the electrodes, or an external substance (as in fuel cells that may use hydrogen gas as a reactant).

Difference between Electric Cell and Battery • An electric cell is a device capable of generating electrical energy from chemical reactions while a battery is a device consisting of one or more cells with external connections provided to power electrical devices.

What is a Primary Cell • A primary cell is a battery that is designed to be used once and is discarded, and cannot be recharged with electricity and reused like a secondary cell (rechargeable battery). • The electrochemical reaction occurring in the cell is not reversible, rendering the cell unrechargeable. In other words the means by which they discharge there energy renders them unrechargeable. • As a primary cell is used, to discharge energy, it uses up the chemicals that create power; when they are gone, the battery stops producing electricity and is useless.

What is a Secondary Cell • A secondary cell, or accumulator is a type of electrical battery which can be charged, discharged into a load, and recharged many times, unlike a primary battery, which is supplied fully charged and discarded after use. It is composed of one or more electric cells. • Rechargeable batteries are produced in many different shapes and sizes, ranging from button cells to megawatt systems connected to stabilize an electrical distribution network. • They are made of several different combinations of electrode materials and electrolytes are used, including lead– acid, nickel–cadmium (NiCd), nickel–metal hydride (NiMH), lithiumion (Li-ion), and lithium-ion polymer(Li-ion polymer).

Characteristics of Primary Cells • A primary cell is a battery that is designed to be used once and thrown away after use. • The electrochemical reaction occurring in the cell is not reversible, rendering the cell unrechargeable. • A primary cell is usually alkaline. • A primary cell is inexpensive and easy to get. • A primary cell is perfect for low voltage applications due the way they are designed. • A primary cell contains mercury and therefore should be recycled. • A primary cell is considered hazardous waste and should not be discarded with regular garbage.

Characteristics of Secondary Cells • A secondary cell is to be recharged after use or being fully discharged. • A secondary cell are made of several different combinations of electrode materials and electrolytes are used, including lead– acid, nickel–cadmium , nickel–metal hydride , lithium-ion and lithium-ion polymer. • A secondary cell initially is more costly than a primary cell however in the long run, secondary cells will provide better cost savings because they recharge when they are dead. • A secondary cell is versatile because they may come in various sizes, shapes, voltages, capacities etc. • A secondary cell is used for devices which demand more power than that of what the primary cells can provide. • Over time, secondary cells lose their ability to hold a charge. • Secondary cells prone to explode or catch fire, if not handled properly therefore handle them with care.

Advantage and Disadvantage of Primary Cells Advantage 1. Inexpensive and easy to acquire.

Disadvantage 1. Once it has been fully discharged it cannot used again.

1. Perfect for Low Voltage applications. 2. Un suitable for more demanding applications like smartphones etc.

2. Replacements are readily available which improve convenience.

3. Is hazardous waste and therefore, should be disposed of correctly.

4. Have consistent reliability and strength.

4. Contains mercury which is toxic.

5. Are widely interchangeable.

Advantage and Disadvantage of Secondary Cells Advantages 1. It can be recharged after fully discharged.

Disadvantage 1. Initially is more costly than a primary cell.

1. Are versatile (can come in 2. Over time secondary cells many shapes, sizes, voltage will lose the ability to hold a etc.) charge. 2. Suitable for more 3. They will explode or catch demanding applications like fire if not handled properly. smartphones etc.

Construction of Primary Cells

Construction of Secondary Cells