INSULATING FILM FOR BATTERY CELL HOUSING, BATTERY CELL, AND SECONDARY BATTERY

Provided in the present disclosure are an insulating film for a battery cell housing, a battery cell, and a secondary battery. A first insulating film is used for covering a first side surface; a second insulating film is used for covering a second side surface; a third insulating film is used for at least covering the junction between a third side surface and a bottom surface, and the junction between the third side surface and a top surface, so that the third side surface is partially exposed; and a fourth insulating film is used for at least covering the junction between a fourth side surface and the bottom surface, and the junction between the fourth side surface and the top surface, so that the fourth side surface is partially exposed. The first insulating film, the second insulating film, the third insulating film, and the fourth insulating film are independent of one another and can be directly processed into shapes matching the corresponding side surfaces of the battery cell housing, eliminating the need for further cutting, and reducing the number of folding areas on the insulating film and the number of times the insulating film is folded, thus reducing insulating film waste, reducing costs, and further effectively avoiding an increase in overall battery cell thickness caused by multilayer folding of the insulating film, thereby improving the space utilization rate of the secondary battery.