Your battery is the main power supply to your computer so making sure it is is proper working condition is crucial.
Flip the device over and locate the battery compartment.
Slide the battery release latch, which you can see in the picture, to the left until the battery is detached from its slot.
A distinguishable pop will be heard when the battery is fully released.
Slowly pull the battery out of its slot, being careful not to damage any of the connectors in the process.