A tape for fixing an electrode assembly comprising: a substrate layer deforming in a longitudinal direction when coming in contact with a carbonate-based electrolyte; and a pressure-sensitive adhesive layer formed on one surface of the substrate layer in a direction parallel to the longitudinal direction of the substrate layer, the substrate layer has a strain of 10% or more in the longitudinal direction according to the following Equation 1: Strain in longitudinal direction = L 2 − L 1 / L 1 × 100 wherein L 1 is an initial length of the substrate layer before the substrate layer comes in contact with the carbonate-based electrolyte; and L 2 is a length of the substrate layer, which is measured after the substrate layer comes in contact with the carbonate-based electrolyte at room temperature in a range of 20 to 30°C for 24 hours; the pressure-sensitive adhesive layer has a peel strength at room temperature in a range of 20 to 30°C of 100 gf/25 mm (39.2 N/m) or more, as measured at a peel angle of 180° and a peel rate of 5 mm/sec with respect to a glass plate, the measurement method of the strain of the substrate layer in longitudinal direction according to the method of the description, the measurement method of the peel strength of the pressure-sensitive adhesive layer according to the method of the description and, the substrate layer comprises thermoplastic polyurethane. a substrate layer deforming in a longitudinal direction when coming in contact with a carbonate-based electrolyte; and a pressure-sensitive adhesive layer formed on one surface of the substrate layer in a direction parallel to the longitudinal direction of the substrate layer, the substrate layer has a strain of 10% or more in the longitudinal direction according to the following Equation 1: Strain in longitudinal direction = L 2 − L 1 / L 1 × 100 wherein L 1 is an initial length of the substrate layer before the substrate layer comes in contact with the carbonate-based electrolyte; and L 2 is a length of the substrate layer, which is measured after the substrate layer comes in contact with the carbonate-based electrolyte at room temperature in a range of 20 to 30°C for 24 hours; the pressure-sensitive adhesive layer has a peel strength at room temperature in a range of 20 to 30°C of 100 gf/25 mm (39.2 N/m) or more, as measured at a peel angle of 180° and a peel rate of 5 mm/sec with respect to a glass plate, the measurement method of the strain of the substrate layer in longitudinal direction according to the method of the description, the measurement method of the peel strength of the pressure-sensitive adhesive layer according to the method of the description and, the substrate layer comprises thermoplastic polyurethane. wherein L 1 is an initial length of the substrate layer before the substrate layer comes in contact with the carbonate-based electrolyte; and L 2 is a length of the substrate layer, which is measured after the substrate layer comes in contact with the carbonate-based electrolyte at room temperature in a range of 20 to 30°C for 24 hours; the pressure-sensitive adhesive layer has a peel strength at room temperature in a range of 20 to 30°C of 100 gf/25 mm (39.2 N/m) or more, as measured at a peel angle of 180° and a peel rate of 5 mm/sec with respect to a glass plate, the measurement method of the strain of the substrate layer in longitudinal direction according to the method of the description, the measurement method of the peel strength of the pressure-sensitive adhesive layer according to the method of the description and, the substrate layer comprises thermoplastic polyurethane.