Remove the battery
First of all you need to detach the battery of your laptop. You need to handle it with care as you will be reusing it. These batteries are usually located in the right side or left side on the bottom of laptops. In most cases logo and model of the laptop are printed on the battery. You need to close the lid of the laptop and flip it in order to remove the battery.
Open the battery
Next you need to open up the battery with help from a screw driver. Remember that some batteries may not have any screws in them.
Lithium-ion battery cells
After unscrewing and opening the battery, you need to look out for the lithium-ion battery cells which are placed inside. These cells are similar in shape of the double-A batteries and power the whole laptop. You need to remove these batteries with care. Remember that the efficiency of the chemical in these batteries lower after constant charging and discharging. You need to note down its voltage before removing.
Get lithium-ion cells
You need to buy lithium-ion cells from a computer hardware store or from any suitable person. Remember that the battery should be of same size and voltage. However, you can get lithium-ion cells with higher milliamp for more battery life.
Replace the batteries
Next you need to take out the old batteries and place the new lithium-ion cells inside the battery. You need to check out the polarity before inserting the new batteries.
In the end, you need to connect the new cells to the wire of the batter. However, take caution when doing this as the battery may burst if exposed to heat or when its casing is damaged.