The lock tab securing the battery flex cable is very delicate. Pulling too much or pulling the white part of the connector easily risks pulling it completely off the main board. Once it's ripped off of the main board, repair of the battery connector will be very difficult.

Use angled tweezers or an opening tool to lift the brown lock latch straight up by 1 mm. Make sure you pull from both sides of the latch.

Be careful not to pull at the white parts that extend to the outer edges of the connector.

Make sure to slide the brown lock tab straight up. The connector is frail and will break if it is accidentally shifted to the side.

Grasp the flex cable with your fingers or tweezers and pull it straight up to disconnect it.

If you're using tweezers, be careful not to grasp the cable too close to the socket, or you'll short the cable contacts.