A battery packaging material comprising: a laminate comprising at least a base material layer, a barrier layer, and a heat-sealable resin layer in this order, wherein when a temperature difference T 1 and a temperature difference T 2 are measured using the following methods, a value obtained by dividing the temperature difference T 2 by the temperature difference T 1 is 0.70 or more: (measurement of the temperature difference T 1) the temperature difference T 1 between an extrapolated melting onset temperature and an extrapolated melting end temperature of a melting peak temperature of the heat-sealable resin layer is measured by differential scanning calorimetry carried out according to the method of the description; (measurement of the temperature difference T 2) in an environment at a temperature of 85°C, the heat-sealable resin layer is allowed to stand for 72 hours in an electrolytic solution, which is a solution having a lithium hexafluorophosphate concentration of 1 mol/l, and a volume ratio of ethylene carbonate, diethyl carbonate, and dimethyl carbonate of 1:1:1, and then dried, and the temperature difference T 2 between an extrapolated melting onset temperature and an extrapolated melting end temperature of a melting peak temperature of the heat-sealable resin layer after drying is measured by differential scanning calorimetry, wherein a resin constituting the heat-sealable resin layer includes polypropylene, the heat-sealable resin layer has a thickness of 10 μm or more and 60 μm or less, and an absolute value of a difference between the temperature difference T 2 and the temperature difference T 1 is 10°C or less. a laminate comprising at least a base material layer, a barrier layer, and a heat-sealable resin layer in this order, wherein when a temperature difference T 1 and a temperature difference T 2 are measured using the following methods, a value obtained by dividing the temperature difference T 2 by the temperature difference T 1 is 0.70 or more: (measurement of the temperature difference T 1) the temperature difference T 1 between an extrapolated melting onset temperature and an extrapolated melting end temperature of a melting peak temperature of the heat-sealable resin layer is measured by differential scanning calorimetry carried out according to the method of the description; (measurement of the temperature difference T 2) in an environment at a temperature of 85°C, the heat-sealable resin layer is allowed to stand for 72 hours in an electrolytic solution, which is a solution having a lithium hexafluorophosphate concentration of 1 mol/l, and a volume ratio of ethylene carbonate, diethyl carbonate, and dimethyl carbonate of 1:1:1, and then dried, and the temperature difference T 2 between an extrapolated melting onset temperature and an extrapolated melting end temperature of a melting peak temperature of the heat-sealable resin layer after drying is measured by differential scanning calorimetry, (measurement of the temperature difference T 1) the temperature difference T 1 between an extrapolated melting onset temperature and an extrapolated melting end temperature of a melting peak temperature of the heat-sealable resin layer is measured by differential scanning calorimetry carried out according to the method of the description; (measurement of the temperature difference T 2) in an environment at a temperature of 85°C, the heat-sealable resin layer is allowed to stand for 72 hours in an electrolytic solution, which is a solution having a lithium hexafluorophosphate concentration of 1 mol/l, and a volume ratio of ethylene carbonate, diethyl carbonate, and dimethyl carbonate of 1:1:1, and then dried, and the temperature difference T 2 between an extrapolated melting onset temperature and an extrapolated melting end temperature of a melting peak temperature of the heat-sealable resin layer after drying is measured by differential scanning calorimetry, a resin constituting the heat-sealable resin layer includes polypropylene, the heat-sealable resin layer has a thickness of 10 μm or more and 60 μm or less, and an absolute value of a difference between the temperature difference T 2 and the temperature difference T 1 is 10°C or less.