BATTERY UNIT, BATTERY MODULE, AND BATTERY PACK

A battery unit includes a secondary battery, a first trap, and a second trap. The secondary battery includes a battery case provided with a gas vent valve, and an electrolyte solution enclosed in the battery case. The first trap includes a mesh material disposed outside the battery case so as to oppose and cover the gas vent valve. The second trap includes a liquid retaining material made of a non-flammable material and disposed further outward of the first trap so as to oppose and cover the gas vent valve.