phone shuts off randomly.. battery change percentage

My phone started to stutter. It's not hot or anything. . Just warm. .. then it would shut itself off with 60 percent. .. I have to remove the battery to turn it back on. . The battery would be low. .. I've had this for about a year and it just started to happen yesterday. .. the battery isn't puffed up

Any help would be appreciated

I called in for a new battery