[user104658]

If it keeps doing it don't keep recharging it until you check if you've got a swollen battery (they literally "puff up" when their physical integrity is compromised) and definitely DO NOT mess with it yourself if the battery is damaged. Charging it can cause it to explode, and accidentally piercing the battery WILL cause it to explode/release toxic gasses unless the battery has been run down to under 5%. The more charge the battery has the bigger the explosion if it pops.