BATTERY PACK

A battery pack for housing a plurality of cell assemblies includes a pack case providing a space for a cell assembly to be seated. The pack case includes: a base plate supporting the lower part of a cell assembly; and a hollow-structured side wall coupled along a border of the base plate to support a side part of the cell assembly. The side wall includes: a gas flow path through which gas can move therein; and a through-hole formed on the gas flow path such that the gas flow path communicates with a space in the pack case, the side wall being coated with a protective layer including at least one among an insulating material and a flame retardant on the inside.