A swelling tape for filling a gap which is formed between a first substrate and a second substrate, wherein one of the first and second substrates is an electrode assembly and the other is a can receiving the assembly, comprising: a substrate layer, deforming in a longitudinal direction when coming in contact with a fluid; and a pressure-sensitive adhesive layer formed on one surface of the substrate layer in a horizontal direction to the longitudinal direction of the substrate layer, wherein the fluid is a carbonate-based fluid electrolyte selected among dimethyl carbonate, ethylmethyl carbonate, diethyl carbonate, methylpropyl carbonate, propylene carbonate, ethylene carbonate, or mixtures thereof, wherein the substrate layer has a strain of 10% or more in a 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 fluid electrolyte; and L 2 is a length of the substrate layer, which is measured after the substrate layer comes in contact in the carbonate-based fluid electrolyte at room temperature being in a range of 20 to 30°C for 24 hours, wherein the pressure-sensitive adhesive layer has a peel strength of 100 gf/25 mm (39.2 N/m) or more, which is measured at room temperature at a peel rate 5 mm/sec and a peel angle of 180° with respect to one glass plate, the pressure-sensitive adhesive layer including an acrylic pressure-sensitive adhesive, a urethane pressure-sensitive adhesive, an epoxy pressure-sensitive adhesive, a silicon pressure-sensitive adhesive, or a rubber pressure-sensitive adhesive or an acryl polymer which is crosslinked with a multifunctional crosslinking agent, the measurement method of the strain of 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, the substrate layer being a urethane-based substrate layer. a substrate layer, deforming in a longitudinal direction when coming in contact with a fluid; and a pressure-sensitive adhesive layer formed on one surface of the substrate layer in a horizontal direction to the longitudinal direction of the substrate layer, wherein the fluid is a carbonate-based fluid electrolyte selected among dimethyl carbonate, ethylmethyl carbonate, diethyl carbonate, methylpropyl carbonate, propylene carbonate, ethylene carbonate, or mixtures thereof, wherein the substrate layer has a strain of 10% or more in a 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 fluid electrolyte; and L 2 is a length of the substrate layer, which is measured after the substrate layer comes in contact in the carbonate-based fluid electrolyte at room temperature being in a range of 20 to 30°C for 24 hours, wherein the pressure-sensitive adhesive layer has a peel strength of 100 gf/25 mm (39.2 N/m) or more, which is measured at room temperature at a peel rate 5 mm/sec and a peel angle of 180° with respect to one glass plate, the pressure-sensitive adhesive layer including an acrylic pressure-sensitive adhesive, a urethane pressure-sensitive adhesive, an epoxy pressure-sensitive adhesive, a silicon pressure-sensitive adhesive, or a rubber pressure-sensitive adhesive or an acryl polymer which is crosslinked with a multifunctional crosslinking agent, the measurement method of the strain of 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, the substrate layer being a urethane-based substrate layer.