I think I have short circuited this phone,

My friend dropped his phone and the cellular will not pick up a network. His power button is also damaged and will not work so we could not turn off the phone. I did try to disconnect the battery first, but instead of using a plastic spudger I went and used a screw driver, (how stupid I know), to disconnect the battery connector. Before I pressed down onto the battery connector I touched the cellular antenna and battery connector and the it Sparked!

The phone will not turn on now and it is completely unresponsive. What has happened? Have I fried the battery or the mother board? Please say its just the battery. I do not have a charger on me to try and power it up that way either.