THERMAL INSULATION MATERIAL FOR BATTERY PACK AND BATTERY PACK

A thermal insulation material for a battery pack includes: a thermal insulation layer; and a first base material and a second base material that are arranged with the thermal insulation layer interposed therebetween. The thermal insulation layer contains a porous structure in which a plurality of particles is connected to form a skeleton, reinforcing fibers, and metal oxide nanoparticles serving as a binder, the porous structure having pores inside and having hydrophobic sites at least on a surface of the porous structure out of the surface and inside of the porous structure, and a percentage mass loss of the thermal insulation layer in thermogravimetric analysis in which the thermal insulation layer is held at 500° C. for 30 minutes is 10% or less.