Lenovo ThinkSystem DE Series Manual page 34

You must insert the metal flange at the front of the battery into the slot on the bottom of the
controller canister and slide the top of the battery beneath the small alignment pin on the left
side of the canister.
5. Move the battery latch up to secure the battery.
When the latch clicks into place, the bottom of the latch hooks into a metal slot on the chassis.
(1) Battery release latch
(2) Battery
6. Turn the controller canister over to confirm that the battery is installed correctly.
Possible hardware damage — The metal flange at the front of the battery
must be completely inserted into the slot on the controller canister (as shown

in the first figure). If the battery is not installed correctly (as shown in the
second figure), the metal flange might contact the controller board, causing
damage to the controller when you apply power.
◦ Correct — The battery's metal flange is completely inserted in the slot on the controller:
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