I hate to be that noob but....

My PSP was dropped onto blacktop from 5 feet in my dad's hands. The battery cover flew off and the battery itself flew out. Now I can only use my PSP if it's plugged into the wall. When the PSP is off (and the battery is in), the charge light is on. However, when I open Battery Information, the Charge Level, Hours Left, and Battery Status fields have a dash (-) in them, and the Power Source is external. Could this be a broken wire connection or something more serious?

I can't send it in because it has 5.00 M33-6 firmware and the warranty sticker was ripped off by the previous owner. Do I risk opening it up and trying to fix it? Thanks to whoever answers.