23-06-2012, 01:40 PM
Seminar on Battery
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INTRODUCTION
Battery or voltaic cell is a combination of many electrochemical Galvanic cells of identical type to store chemical energy and to deliver higher voltage or higher current than with single cells.
The battery cells create a voltage difference between the terminals of each cell and hence to its combination in battery. When an external electrical circuit is connected to the battery, then the battery drives electrons through the circuit and electrical work is done. Since the invention of the first Voltaic pile in 1800 by Alessandro Volta, the battery has become a common power source for many household and industrial applications, and is now a multi-billion dollar industry.
HISTORY
The name "battery" was coined by Benjamin Franklin for an arrangement of multiple Leyden jars ,an early type of capacitor after a battery of cannon. The common usage includes a single electrical cell in the definition. An early form of electrochemical battery called the Baghdad Battery may have been used in antiquity. However, the modern development of batteries started with the Voltaic pile, invented by the Italian physicist Alessandro Volta in 1800.
WORK
A battery is a device that converts chemical energy directly to electrical energy. It consists of one or more voltaic cells; each voltaic cell consists of two half cells connected in series by a conductive electrolyte containing anions and cations. One half-cell includes electrolyte and the electrode to which anions (negatively-charged ions) migrate, i.e. the anode or negative electrode; the other half-cell includes electrolyte and the electrode to which cations (positively-charged ions) migrate, i.e. the cathode or positive electrode. In the redox reaction that powers the battery, reduction (addition of electrons) occurs to cations at the cathode, while oxidation (removal of electrons) occurs to anions at the anode. The electrodes do not touch each other but are electrically connected by the electrolyte, which can be either solid or liquid. Many cells use two half-cells with different electrolytes. In that case each half-cell is enclosed in a container, and a separator that is porous to ions but not the bulk of the electrolytes prevents mixing.
Battery Capacity & Discharging
The more electrolyte and electrode material there is in the cell, the greater the capacity of the cell. Thus a small cell has less capacity than a larger cell, given the same chemistry, though they develop the same open-circuit voltage. The capacity of a battery depends on the discharge conditions such as the magnitude of the current, the duration of the current, the allowable terminal voltage of the battery, temperature and other factors. The available capacity of a battery depends upon the rate at which it is discharged. If a battery is discharged at a relatively high rate, the available capacity will be lower than expected.
[attachment=25243]
INTRODUCTION
Battery or voltaic cell is a combination of many electrochemical Galvanic cells of identical type to store chemical energy and to deliver higher voltage or higher current than with single cells.
The battery cells create a voltage difference between the terminals of each cell and hence to its combination in battery. When an external electrical circuit is connected to the battery, then the battery drives electrons through the circuit and electrical work is done. Since the invention of the first Voltaic pile in 1800 by Alessandro Volta, the battery has become a common power source for many household and industrial applications, and is now a multi-billion dollar industry.
HISTORY
The name "battery" was coined by Benjamin Franklin for an arrangement of multiple Leyden jars ,an early type of capacitor after a battery of cannon. The common usage includes a single electrical cell in the definition. An early form of electrochemical battery called the Baghdad Battery may have been used in antiquity. However, the modern development of batteries started with the Voltaic pile, invented by the Italian physicist Alessandro Volta in 1800.
WORK
A battery is a device that converts chemical energy directly to electrical energy. It consists of one or more voltaic cells; each voltaic cell consists of two half cells connected in series by a conductive electrolyte containing anions and cations. One half-cell includes electrolyte and the electrode to which anions (negatively-charged ions) migrate, i.e. the anode or negative electrode; the other half-cell includes electrolyte and the electrode to which cations (positively-charged ions) migrate, i.e. the cathode or positive electrode. In the redox reaction that powers the battery, reduction (addition of electrons) occurs to cations at the cathode, while oxidation (removal of electrons) occurs to anions at the anode. The electrodes do not touch each other but are electrically connected by the electrolyte, which can be either solid or liquid. Many cells use two half-cells with different electrolytes. In that case each half-cell is enclosed in a container, and a separator that is porous to ions but not the bulk of the electrolytes prevents mixing.
Battery Capacity & Discharging
The more electrolyte and electrode material there is in the cell, the greater the capacity of the cell. Thus a small cell has less capacity than a larger cell, given the same chemistry, though they develop the same open-circuit voltage. The capacity of a battery depends on the discharge conditions such as the magnitude of the current, the duration of the current, the allowable terminal voltage of the battery, temperature and other factors. The available capacity of a battery depends upon the rate at which it is discharged. If a battery is discharged at a relatively high rate, the available capacity will be lower than expected.