Why does my Lumia 520 automatically shutdown?

[Windows Central Question]

I've been using Lumia 520 for over a year now. It automatically shuts down while in my pockets and only way to turn it on is to plug it in a power source, on doing that it shows empty battery but the battery wasn't empty and it just shows the charging sign all over the screen and doesn't actually start. The minute it is taken off the power source it again shuts down. It starts when given a pat on the back slightly powerful one and then all the date and time is wrong.
What should i do because it is getting on my nerves and it does so 5-6 times a day.

 

[pankaj981]

Looks like either its a faulty battery problem or the battery contact is lose. Try to see if adding some padding to the back cover helps in securing the battery