Lumia 520 Battery Problem Help!

[WPCentral Question]

Recently the Windows phone update 8.1 came out and as my Lumia was updating the battery power died. Logically I set it recharging but now it comes back on and updates but once again the battery goes in the middle of updating to Windows 8.1. A continuous loop has evolved as a result. As of now I'm not sure if it's the battery or the actual update causing this malfunction. What should I do!?