not the thing in the red arrows, *** I'm talking about the 'black vent' to the left of the 12v battery, what does it vent f?
Since the Prius battery is in inside the passenger compartment it has a vent to allow the offgasing hydrogen to vent outside. The prius uses an AGM(aborbed gass matt) battery and should not really off gas at all but its just a safty thing.
The black plastic duct shown in the OP's attached photo is the duct that carries the traction battery's cooling air out of the car. Air to cool the traction battery enters in a vent grille by the rear seat back, flows through the traction battery to cool it, and leaves the car through that duct.
The black duct is the cooling air exhaust from the large hybrid battery (under the back seat.) Because battery charging and discarding may release toxic fumes, they must be exhausted to the outside. Between the back seat and the passenger side back door, there is an intake vent for the fan the moves all that air around. That fan also must be inspected and cleaned regularly. If the 12 Volt battery has a sealed top, it will also usually have a small rubber hose that goes to the same exit point. -Graeme- 2004 Prius with >190,000 miles. Sent ?.
