P0A80 and Clogged Battery Vent

I have a 2014 priusV with 138K miles on it, all of the lights or most of them suddenly came on with no warning at all, we stopped the car and then upon turning it back on, only 3 lights were on. None of them were the overheating light. We took it to the dealer and they gave me the same dog hair excuse which is crazy because we got our dog (which is not a long haired dog) 2 months ago. I highly doubt the dog hairs were the problem. If there was overheating, wouldn't the overheating warning light come on?
Anyways, tomorrow I should hear back from corporate, they will tell me what they decided to do. Oh, and I was charged $140.00 for inspection and was told that I needed to replace the Hybrid battery pack, found code P0A80 and found battery clogged, battery not receiving ventilation (no warning lights came on), will need to replace hybrid battery, replace filter and clean surroundings.$4183.83 NOT including tax. I declined as I wanted to check all my options before paying that hefty sum. I also noticed that I never got a backseat mat, the mat sits on top of the vent (protecting what goes in) but I told this to the representative and they said sometimes mats don't come included.
Anyways, I highly doubt that the battery just dies without warning due to "overheating and clogging from dog hair". But that is what the service guy told me and told corporate Toyota.
any input greatly appreciated.

 

Oh, and I asked them to clean the clogging and they said "at this point that will not do anything", so they refused to clean it unless I get the new battery. They also offered me 1K dlls for my car and told me it was probably a better idea to put the 1k they would give me, into buying a new car.