Use a pair of tweezers to pull out the left adhesive tab from underneath the battery.

The adhesive tab underneath the battery can rip very easily. Make sure you pull out the tab in a slow and steady motion and in a flat angle. To prevent the adhesive tab from ripping, it's helpfull to twist the strip around the tweezers.

In case one of the adhesive tabs rips and it‘s not possible to pull it out completely, you can use isopropyl alcohol or an heated iOpener to loosen the adhesive. After the adhesive is soft enough use a prying tool such as an opening pick or a plastic card to pry out the battery.