NVNV VR Fan for Oculus Quest 2

i have had this nvnv fan for quite a while, and at first it worked great. however not the battery life of 180 minutes that was advertised, more like an hour maximum. and after using this for a while it seems to over-heat and turn off, not allowing me to turn it back on for roughly 10 minutes. there dosent seem to be any way to open it up and look inside either. also amazon has this same thing for 25 dollars.