The wires to the battery are soldered to the motherboard. You may also check the soldering techniques guide for additional tips on soldering.

If your device's wiring doesn't exactly match these photos, snap a picture or make a note of what color wire goes to which contact on the motherboard before you detach them. (A mis-wired battery could cause electrical shorts and ruin the tablet for good.)

Using a soldering iron, desolder the four wires from the motherboard.

Once the wires are free from the motherboard, your battery should be free to remove from your device.