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

A lithium-ion battery and separator technology, applied in the field of low-heat-shrinkable lithium-ion battery separator and its preparation, can solve problems such as narrowing of width, short circuit of positive and negative electrodes, and violent tendons of winding, so as to prevent winding wrinkles and reduce heat shrinkage rate, reduce the effect of heat shrinkage

Inactive Publication Date: 2021-08-13
JIANGSU HORIZON NEW ENERGY TECH CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

In addition, the performance of the separator has an important impact on the cycle performance and safety performance of the lithium-ion battery. If the thermal shrinkage of the separator is too large, it is easy to cause adverse effects such as winding tendons during the winding process of the base film; During the baking process and the battery heating process, lateral shrinkage is prone to occur, resulting in narrowing of the width, and direct contact between the positive and negative electrodes causes a short circuit

Method used

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

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[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: ...

Embodiment 2

[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: Secon...

Embodiment 3

[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: ...

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Abstract

The invention discloses a low-thermal-shrinkage lithium ion battery diaphragm and a preparation method thereof. The lithium ion battery diaphragm is prepared from the following raw materials in percentage by weight: 70 to 75 percent of white oil, 10 to 15 percent of ultra-high molecular weight polyethylene, 10 to 15 percent of high-density polyethylene, 0.1 to 1 percent of propylene-ethylene block copolymer, 0.1 to 0.2 percent of modifier and 0.1 to 0.2 percent of compatilizer. According to the low-thermal-shrinkage lithium ion battery diaphragm and the preparation method thereof, the stability of a film in a stretching process is guaranteed by limiting and precisely proportioning raw materials, and then transverse shrinkage caused in transverse stretching processes is reduced by limiting the temperature, the stretching ratio and the retraction ratio in the primary transverse process and the secondary transverse process and jointly designing the length ratio of a stretching area to a non-stretching area to a retraction area of a transverse stretching drying oven; and the setting temperature is increased in a heat setting area, so that the heat shrinkage of the diaphragm is reduced, winding wrinkles caused by shrinkage deformation during diaphragm winding are prevented, the battery short-circuit risk caused by excessive heat shrinkage of the diaphragm is avoided, and the overall performance of the lithium ion battery is improved.

Description

technical field [0001] The invention relates to the technical field of battery separators, in particular to a low heat shrinkage lithium-ion battery separator and a preparation method thereof. Background technique [0002] Lithium-ion batteries are composed of four parts: positive electrode material, negative electrode material, separator and electrolyte. Among them, the diaphragm is an important part of the lithium battery, which plays the role of isolating the positive and negative poles; at the same time, it can limit the increase of the current when the battery is overcharged or the temperature rises, preventing the battery from short-circuiting and causing an explosion; therefore, it is necessary to The diaphragm must have high mechanical strength. In addition, the performance of the separator has an important impact on the cycle performance and safety performance of the lithium-ion battery. If the thermal shrinkage of the separator is too large, it is easy to cause ad...

Claims

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Application Information

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IPC IPC(8): H01M50/414H01M50/417H01M50/463H01M50/494H01M50/403H01M10/0525
CPCH01M10/0525Y02E60/10
Inventor 赵洪亮刘涛涛翁星星陈朝晖
Owner JIANGSU HORIZON NEW ENERGY TECH CO LTD