CURRENTLY ALL PHONES ARE MADE OF LITHIUM ION CELLS THE MAJOR ADVANTAGE OF LITHIUM ION IS HIGH ENERGY DENSITY. WHICH MEANS THE PHONE NEED TO LONG LAST FOR MORE TIME AND HIGH POWER REQUIRED TO RUN GAMES SO HIGH DISCHARGE RATE IS NEEDED IN ORDER TO PROVIDE MORE CHARGE SO MORE LI ION CELLS ARE PACKED IN THE SINGLE BATTERY.
The three primary functional components of a lithium-ion battery are:
1 Positive electrode.
2 Negative electrode.
3 Electrolyte .
Positive electrode(cathode) is made up of lithium ions is mixed with the some proportions of oxides(to make lithium stable),carbon and other bonding agents(binders).lithium ion easily react able with nature so its easy to remove the electrons from atom compared to other material.lithium ion is coated in aluminium foil sheet which is easy to fold .
Negative electrode(anode) is made of graphite is mixed with some proportions of carbon and binders,then the mixture is coated in copper foil.The function of anode(graphite) is to store the lithium ions when the battery is in charged condition.
Electrolyte acts as catalyst to make a battery conductive by promoting the movements of ions from cathode to anode on charge and reverse on discharge.Here in lithium ion battery use lithium salt as electrolyte.
CHARGE AND DISCHARGE
If power source is connected across the battery , the positive side of the power source will obviously attract and remove electrons from the lithium atoms of metal oxide these electron flow through the external circuit as they cannot flow through the electrolyte and reach the graphite layer in the mean time the positively charged lithium ions are attracted towards the negative terminal through the electrolyte. it reaches the graphite layer space and get trapped .once all the lithium atom reach the negative terminal or graphite sheet the cell is fully charged . if is unstable state the electrons should return to its own position. so now the power source is removed (means charge is full ) load is connected (if you started using the mobile) lithium ion wants to go back to the stable state as part of metal oxide due to this tendency the lithium ion move through electrolyte and the electron flow through the load.once all the electron is moved the discharge is done.This cycle is done every time to charge and discharge the phone battery.