Sometimes laptop get shutdown on it's own

I got water spilled on my macbook pro 13 non retina A-1278 model. After that i opened the laptop and completely dried it up but it was not working normally though it was getting started if i kept pressed Command button, it works fine, but as soon i left the command button it got shutdown. I took it to service center they told me that it's battery problem, we need to replace the battery to make it work properly. I aksed them to do so, even after changing battery sometimes it get shut down and will keep booting shut down relentlesly. I mean it is behaving weirdly, for one and half day it worked properly then it suddenly got shut down and kept booting shut down and when i left it again for night, in morning it started beahving normally.