Replace your iPod Mini battery
Step 6:
Reassemble the iPod Mini
Hold the motherboard, making sure the battery is in place, and slide it, bottom first, through the top of the Mini body. Be sure that the motherboard slides in under the internal metal grooves. Tuck in the battery cable if necessary. Once it's seated tightly, put back the two tiny screws up top, then reconnect the cable on the bottom end. Then push the metal clip so that each corner fits in its respective groove. It should snap in. Finally, snap in the white bottom and top covers--the existing adhesive should stick well enough, but if you want to reinforce it, use a tiny bit of strong glue.
Replace your iPod Mini battery