A packaging bag includes a first shell and a second shell. A first bonding layer of the first shell is bonded to a second bonding layer of the second shell to form a sealing portion. The sealing portion includes a first adhesive overflow region, a sealing region, and a second adhesive overflow region. The sealing region includes a first segment and a second segment. Along a width direction of the sealing portion, the sealing region is located between the first adhesive overflow region and the second adhesive overflow region. The second segment is closer to the electrode assembly than the first segment. An average thickness of the second segment is less than an average thickness of the first segment.