A battery pack assembly includes, among other things, a first battery component, a different, second battery component and an enclosure that has a cover secured to a tray to provide an interior. The first and second battery components are disposed within the interior. The cover has a first area that is disposed directly above the first battery component. The cover has a second area that is disposed directly above the second battery component. The battery pack assembly further includes a rib of the cover. The rib extends into the interior from the first area. The rib is configured to contact the first battery component to inhibit relative movement of the second area toward the second battery component.