Battery cell, battery, and electric apparatus

A battery cell, comprising:

• an electrode assembly;
• and
• a packaging bag accommodating the electrode assembly, wherein the packaging bag comprises a first shell and a second shell;
• the first shell comprises a first bonding layer;
• the second shell comprises a second bonding layer;
• the first bonding layer is bonded to the second bonding layer to form a sealing portion;
• the sealing portion comprises a first adhesive overflow region, a sealing region, and a second adhesive overflow region;
• and 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;
• and
• the sealing region comprises a first segment and a second segment;
• along the width direction of the sealing portion, the second segment is closer to the electrode assembly than the first segment;
• and an average thickness of the second segment is less than an average thickness of the first segment.