Once the battery pack and the memory module (DIMM) have been removed, follow the instructions below on how to remove the backup battery.
Removing the backup battery
Disconnect the battery as indicated in the picture below.
WARNING: The backup battery is a lithium battery and can cause a fire, an explosion, or severe burns. Do not recharge it, remove its polarized connector, disassemble it, heat it above 100°C (212°F), incinerate it, or expose its cell contents to water. Dispose of the battery as required by local ordinances or regulations. The use of an incorrect battery can result in ignition or explosion of the battery.