Use the point of a spudger to push on alternating sides of the battery connector to "walk" it out of its socket on the motherboard.

It may take a lot of alternating before the connector comes out. Be patient, and don't pull on the cables.

To reconnect the cable, align the connector and use a spudger or clean fingernail to push it fully into the socket.

Don't push on the cables themselves, or you may damage the connector.

Lift the battery upwards to remove it from the device.