SILICA AEROGEL POWDER USED IN THERMAL INSULATOR FOR BATTERY PACK AND THERMAL INSULATOR FOR BATTERY PACK

When a silica aerogel powder used in a thermal insulator for a battery pack is measured by a nitrogen adsorption amount measurement method, a specific surface area and a pore volume at a relative pressure of 0.99 measured based on an adsorption isotherm that is obtained are 550 m/g or more, and 3.5 mL/g or more and 5.0 mL/g or less, respectively, and when a [mL/g] is a pore volume at a relative pressure of 0.93, b [mL/g] is a pore volume at a relative pressure of 0.965, and c [mL/g] is a pore volume at a relative pressure of 0.99, the following conditions (i) and (ii) are satisfied: