Did the update mess up my iphone battery?

I was updating my iphone to the new software up date at Dunkin and then i decided to leave without the update finished, and still haven't finished the update since i have to Wi-Fi at home and now my battery is going nuts, when i charge it it gets stuck on a number or sometimes everytime the percentage goes up
the battery shuts off and shuts back on to the new percentage. When i use it at school it shuts off like 10 times and then gets stuck on a battery percentage. I already deleted and reseted all content & settings from my phone but still no help? Do i have to buy a new battery or what by the way its an iphone 5

Your best bet is going to your phone supplier they will help you