[Beemmerr206]

I have a 2008 x3. First the airbag light turned on after battery died. Was able to get it to run again but then started having electrical issues. Opened battery compartment and battery is sitting in 2 inches of water. Trying to identify where water is coming in now. Have removed enough paneling to find a pad drenched in water. I don’t know what it’s for. Panels behind it are dry. But I assume the water from this soaking pad is dripping down to this metal cover. I can see water beneath it in a puddle also.

Does anyone know what this black plastic pad is for and what might be draining into it to make it sopping wet?

What is under this metal cover at the bottom. I unscrewed the top two nuts but it’s still attached to something? Or do I need to remove the styrofoam insert to get it out?