Updated: Feb 19
The high voltage hybrid battery cooling fan is a very important, integral part of the battery system. In the Toyota Hybrid it blows air from the cars interior into the battery casing which flows between the modules helping to keep them cool. In a Prius generation 2 the intake vent it is at the side of the rear seat, whereas in a Toyota Auris estate and Yaris hybrid, the the intake vents are at floor level below the rear seats. Any particles, fluff etcetera which find their way into the battery casing could potentially cause problems by becoming lodged between the modules, causing hot spots, blocking air flow thus reducing battery life.
Toyota Estima Hybrid Generation 1 Blower motor Battery Cooling Fan after Servicing
The air intake vents for the HV battery cooling fan should be checked periodically, as if the air flow becomes reduced by obstructions of any type, it could cause the HV battery to overheat. This also reduces the batteries life span.
Figure .1 shows the fan from a 2006 generation 2 Toyota Prius before cleaning.
from a repair carried out By Hybrid Repair Service In London, at the beginning of July 2020
Figure .2 shows the same fan almost ready to return to service
At Hybrid Repair Service each high voltage battery repair includes cleaning of the fans as part of the hybrid repair as standard.