Lithium ion battery

If you are one of them who wonders how cellphone battery works then here is a quick article for you. After the development of first generation computers we moved a step ahead and there came the development of portable computers. But the problem was portable electronics can't be connected to the current to use always. This problem could be overcome with the help of batteries. The term battery means a group of electric cells working together to supply some power output. Now a days most of the computer system including phones, tablets, laptop runs on rechargeable batteries. One of the very popular rechargeable battery that is widely used today is lithium-ion battery.

Lithium ion battery are not only used in electronics but are also used in electrical vehicles, military and aerospace industry. To know about how the lithium ion battery actually works we have to go through its electrochemistry. A lithium ion battery is a type of electrochemical cell which converts chemical energy to electrical energy within the battery. In the case of a lithium-ion battery, the lithium ions are ‘tied’ to an electron within the structure of the anode. When the battery discharges, the intercalated lithium ions are released from the anode, and then travel through the electrolyte solution to be absorbed (intercalated) in the cathode. Before you can use the battery you have to charge it. Which charging oxidation reactions occurs at cathode. That means it loses some electrons. To maintain the charge balance the cathode have to dissolve some equal amount of positively charged lithium ion in the electrolyte. The discharged electrons travels to the anode. Here the anode is made up of graphite. The electrons are there intercalated within the graphite. The electrons tie up with the lithium ion at the anode.

While discharging the lithium ions moves from anode and travels to the cathode through the electrolyte solution. This also releases electrons that moves through an external wire which sets up a current in the circuit that we use. When the cathode becomes full of lithium ions, the battery is dead and we have to charge it to use again. While charging, the electrochemical process continues again. The electrolyte in the lithium ion cell is usually a solution if lithium salt dissolved in some solvent like dimethyl carbonate. Lithium ion is small due to which a large number of ions can be stored in both the electrodes. This is why lithium ion batteries are of much higher density. Comparing to other batteries, lithium ion battery operated at a much higher voltage. To balance this an equal amount of electrons also discharges. A single lithium ion cell gives a voltage of 3.6 V.

The anode is made up of graphite. After a long usage a large amount of insertion of lithium ion into graphite can break it. Cathode is made up of Lithium cobalt oxide(LiCoO2).

The cell reactions are:

During discharge

             LiC6 + CoO2 ⇄ C6 + LiCoO2

Oxidation:

              LiC6 → C6 + Li+ + e-

Reduction:

             CoO2 + Li+ + e- → LiCoO2

Apart from the anode, cathode and electrolyte a lot of things are involved in making a lithium ion battery. They are

1. Voltage tap
2. Mains connector
3. Voltage regulator circuit
4. Temperature sensor
5. Sensor to monitor charge state

Lithium ion batteries available in various shapes and sizes they are

1. Small cylinder
2. Large cylinder
3. Flat
4. Rigid

Lithium ion batteries were first developed in late 1970s. Three scientists, John B. Goodenough, M. Stanley Whittingham, and Akira Yoshino received novel prize in chemistry for developing such a battery that can make portable electronics success.

Panasonic created the smallest Li-ion battery in 2014. It is pin shaped. It has a diameter of 3.5mm and a weight of 0.6g.

The avarage battery life of a fully functioning lithium ion battery is about 2 to 3 years. Have you ever wondered what happens after the mobile phone battery is totally dead? Well if you have used a phone for almost 3 years or later the answer would be known to you. Without any physical impact a normal lithium ion battery lasts 2 to 3 year and after that its totally dead. But you don't have to worry about the phone because the dead battery doesn't effect the health of the phone. When the battery dead changing the battery can be a good option rather than wasting the whole phone. A normal cell phone lithium ion battery lasts upto 1000 or a little more charge cycle. Now a days the cell phone battery comes pre-attached. So the battery can be changed with the help of a service centre.