Abstract: A defrost duct assembly for a vehicle includes a housing having a wall that defines an air passage. The air passage extends between an inlet and an outlet of the housing. The wall includes an opening into the air passage. A noise attenuation panel is attached to the housing, and covers the opening in the housing. The noise attenuation panel is an acoustic material that is operable to attenuate noise from within the passage of the housing, while maintaining sufficient air flow to adequately defrost a front windshield of the vehicle. The housing may include multiple outlets and multiple openings covered by one or more noise attenuation panels. The noise attenuation panel is preformed to mate with the housing, and minimize disturbance to the flow of air within the passage.

Abstract: A cooling duct connects a passenger compartment of a vehicle and an energy storage system in fluid communication, and directs a flow of air from the passenger compartment to the energy storage system to cool the energy storage system. The cooling duct includes a first portion that is formed from a non-porous material, and a second portion that is formed from a porous material. The first portion and the second portion are attached to define an enclosed flow path. The second portion includes an airflow resistivity that allows air infiltration into the second portion, through the porous material, at a rate of between zero percent (0%) and twenty percent (20%) of a minimum flow rate when an inlet of the cooling duct is unobstructed, and at a rate of at least thirty percent (30%) when the inlet is completely obstructed.