Tesla MODEL X 2019 Owner's Manual page 9

Keys and Doors
2. Remove the battery by carefully releasing
it from the retaining clips at an angle.
8
3. Insert the new battery (type CR2354) with
the '+' side facing up. The battery fits
snugly so you must slide it into position at
an angle toward the Positive contact (the
contact located near the center of the
key), then press down firmly on the other
side, ensuring it is held firmly in its
intended position.
Note: Tesla recommends using Panasonic
CR2354 batteries. These can be
purchased through online retailers, local
supermarkets, and drug stores.
Caution: The battery should press
against the spring on the positive
contact. Do not place the battery on
top of the contact and force it down
vertically. Doing so may damage the
contact.
Note: Wipe the battery clean before fitting
and avoid touching the battery's flat
surfaces. Finger marks on the flat surfaces
of the battery can reduce battery life.
4. Holding the cover at an angle, align the
tabs on the widest side of the cover with
the corresponding slots on the key, then
press the cover firmly onto the key until it
snaps into place.
5. Test that the key works by unlocking and
locking your vehicle.
Model X Owner's Manual