Abstract: In large-scale industrial production, it was prone to welding defects such as porosity, poor formation and blow holes in laser welding of power battery components, which reduced safety and reliability of vehicle operation. In this paper, the specific position of laser welding application in power battery was analyzed. Welding defects were classified according to different welding positions, and causes of defects such as incomplete penetration, porosity, collapse, blasting hole and crack were discussed. For specific application scenarios such as joining of shell and cover plate of battery, sealing of explosion proof valve of battery, welding of battery pole and connection of pole ears and busbar, methods for reducing welding defects and improving welding quality were concluded, which included improving welding process, adjusting characteristics of laser source and optimizing welding sequence. On this basis, application of intelligent manufacturing techniques in laser welding of power batteries was further introduced and future development of laser welding technology in the field of power batteries was prospected.Highlights: (1) Defects and their causes in laser welding of power batteries were classified and introduced on the basis of welding positions.(2) Methods to reduce defects in laser welding of power batteries were summarized in accordance with welding process, laser source and welding sequence.(3) Application of intelligent laser welding technology in power batteries was concluded and its future development was prospected.