Did unibody Macbook Pros have a backup battery (CMOS / PRAM)?

My mid-2009 13" unibody MacBook Pro died years ago. It's probably not worth fixing. I'm just curious if a dead CMOS/PRAM battery could have caused its demise?

iFixIt doesn't list any non-primary batteries in its online store or replacement guides for any unibody Macbook Pros.

Did these models lack one altogether or was it just soldered to the logic board (In which case it'd be kind of like planned obsolescence) ?

Solution 1:

I don't know the precise details on this, per model, but the general rule of thumb is if the main battery is removable on a Macbook [Pro] then it has either a "CMOS" battery or a super capacitor.

I'm pretty sure the Unibodies had the super capacitor, which assuming it still works is powered by the regular charging process. If it's failed, even after a good couple of main battery cycles on the charger, the primary symptom is probably that the date keeps resetting. It should still boot, though I saw mentioned in one site that it may not if it's cold.
I'd check that before investigating further.

I found this on iFixit - https://www.ifixit.com/Answers/View/394346/MacBook+Pro+13%22+Mid+2009+what+capacitor+I+need