Warning:
This is a dangerous condition. You should not continue to use the device because a swollen battery can leak chemicals or short-circuit, potentially causing a fire. You should take the device to a qualified technician for battery replacement as soon as possible.
Repair Details:
Replace with a new battery.
How to Slow Down Battery Degradation
Avoid high temperatures.
Heat is the biggest enemy of lithium-ion batteries, causing them to degrade very quickly.
Optimize charging habits.
Try to keep the battery level between 20-80%. Lithium-ion batteries do not perform well when frequently charged to 100%.
Use smart device settings.
Certain settings can help reduce the load on the battery.