Hello everyone, I have a dell latitude 7370 and its battery is being dead after 20 mins when unplugged. When it charges to 100%, the battery drains to 99% and never charges back to 100%. the charging indicator (this:)

 

 blinks continuously when fully charged. I tried by resetting the pc, performing clean boot, changing power options but nothing worked. now the power indicator is blinking red and battery is not charging up than 35%. The laptop turns off if i unplug it. 

Specs:

CPU: intel core m5 6y57

GPU: intel hd 515

8 gb ram 

Please help me out with this.