2016 Prius V Two: What part is this?

I’m new to this forum so apologies if this has already been identified.

I have a 2016 Prius V Two that I bought used and while I was cleaning out the rear cargo area, I found this piece lying inside the spare tire area.

Can someone please help me identify what this is and where it should be?

 

Thanks! I checked the area you mentioned and could not locate any vents (pictures attached). I removed the panel but didn’t see anything that matched up.

 

Mystery Solved! Thank you @jdenenberg for getting me in the ballpark.

I took a closer look at the air intake setup for the battery and noticed the tube went underneath the carpet of the back passenger side seat. I removed the hose and voila! The mystery piece was the screen for the end that’s underneath the seat!

I sifted through the maintenance records of the car from prior to me owning it and the dealership had done a service on the battery at some point but clearly didn’t do a complete put back together of everything they pulled out.