Low-thermal-shrinkage lithium ion battery diaphragm and preparation method thereof

[0031] S1: Mixing: Stir and mix other raw materials except white oil evenly to form a mixture;

[0032] S2: Melt extrusion: mix the mixture and white oil evenly, melt, set the screw speed to 35rmp, the extrusion temperature to 200°C, the casting temperature to 22°C, and extrude to form a sheet;

[0033] S3: Longitudinal stretching: set the process parameters of longitudinal stretching as follows: the stretching temperature is 105°C, the stretching ratio is 7.5, and the sheet is stretched longitudinally to obtain film A;

[0034] S4: One-time transverse stretching: set the process parameters of one-time transverse stretching as follows: stretching temperature is 120°C, stretching ratio is 8.7, stretching retraction ratio is 12, "stretching zone - no stretching zone - retraction The length ratio of the area" is 1:1:1, and the film A is stretched transversely once to obtain the film B;

[0035] S5: extraction: extracting the film B in a solvent to obtain a film C;

[0036] S6: Sec

[0040] S1: Mixing: Stir and mix other raw materials except white oil evenly to form a mixture;

[0041]S2: Melt extrusion: mix the mixture and white oil evenly, melt, set the screw speed to 35rmp, the extrusion temperature to 200°C, the casting temperature to 22°C, and extrude to form a sheet;

[0042] S3: Longitudinal stretching: set the process parameters of longitudinal stretching as follows: the stretching temperature is 105°C, the stretching ratio is 7.5, and the sheet is stretched longitudinally to obtain film A;

[0043] S4: One-time transverse stretching: set the process parameters of one-time transverse stretching as follows: stretching temperature is 120°C, stretching ratio is 8.5, stretching retraction ratio is 12, "stretching zone-no stretching zone-retraction The length ratio of the area" is 1:1:1, and the film A is stretched transversely once to obtain the film B;

[0044] S5: extraction: extracting the film B in a solvent to obtain a film C;

[0045] S6: Secondar

[0049] S1: Mixing: Stir and mix other raw materials except white oil evenly to form a mixture;

[0050] S2: Melt extrusion: mix the mixture and white oil evenly, melt, set the screw speed to 35rmp, the extrusion temperature to 200°C, the casting temperature to 22°C, and extrude to form a sheet;

[0051] S3: Longitudinal stretching: set the process parameters of longitudinal stretching as follows: the stretching temperature is 105°C, the stretching ratio is 7.5, and the sheet is stretched longitudinally to obtain film A;

[0052] S4: One-time transverse stretching: set the process parameters of one-time transverse stretching as follows: stretching temperature is 120°C, stretching ratio is 8.6, stretching retraction ratio is 12, "stretching zone - no stretching zone - retraction The length ratio of the area" is 1:1:1, and the film A is stretched transversely once to obtain the film B;

[0053] S5: extraction: extracting the film B in a solvent to obtain a film C;

[0054] S6: Sec