Preparation method of lithium ion battery diaphragm

Abstract

The invention discloses a preparation method of a lithium ion battery diaphragm, which comprises the steps of firstly preparing suspension and coating the suspension on a porous flexible substrate; and then drying the suspension to have 10-20% of solvent content, rolling and continuously drying to obtain the lithium ion battery diaphragm. The preparation method of the lithium ion battery diaphragm has the advantages that when the coating is dried to 10-20wt% of the solvent content, the rolling treatment is carried out, the bonding force of insulated nano particles and the porous flexible substrate can be remarkably improved, thereby providing guarantee for the high-temperature resistance of the diaphragm. The porosity of the lithium ion battery diaphragm is 60-70%, the aperture is 50-110nm, and the diaphragm can resist the high temperature of 400 DEG C.

Description

technical field

[0001] The invention relates to a preparation method of a lithium ion battery diaphragm. Background technique

[0002] Lithium-ion batteries have the characteristics of long cycle life, high specific energy, good safety performance, small size, light weight, and no memory. They are widely used in mobile phones, notebook computers and other fields. Lithium-ion batteries generally adopt lamination or winding The positive and negative electrodes are separated by a diaphragm during the lamination or winding process to prevent direct electronic pathways between the positive and negative electrodes, and at the same time require the ions in the electrolyte where the positive and negative electrodes are located to freely pass through the diaphragm , to form an ionic current, so the separator is required to have good electrical insulation and a microporous structure that allows ions to pass through. The current separator is made by coating a coating composition on a ...

Examples

Embodiment 1

[0019] The preparation method of the lithium-ion battery diaphragm of the present embodiment is as follows:

[0020] 1) Add a certain amount of N-methylpyrrolidone into the container, heat to 90°C, add 10 parts of polyvinylidene chloride and stir until completely dissolved, then add 10 parts of aluminum oxide (particle size is 10nm), and continue stirring for 90 minutes Obtain suspension, the solid content of suspension is 35wt%;

[0021] 2) Uniformly coat the prepared suspension on the porous flexible substrate to form a coating. The coating thickness of the coating is 1 μm, and the porous flexible substrate is a polyolefin porous film;

[0022] 3) Heat and dry the porous flexible substrate coated with the coating at 60°C until the solvent content of the coating is 10wt%, and then roll the coating, and the rolling strength is 300 N / cm 2 , and then continue to bake at 100°C until completely dry to obtain a lithium-ion battery separator.

[0023] The lithium-ion battery separ...

Embodiment 2

[0025] The preparation method of the lithium-ion battery diaphragm of the present embodiment is as follows:

[0026] 1) Take a certain amount of N,N-dimethylacrylamide and add it to the container, heat it to 90°C, add 30 parts of polyacrylic acid and stir until completely dissolved, then add 20 parts of zirconia (particle size is 200nm) and 5 parts of polyacrylic acid Vinylpyrrolidone, and continued stirring for 90 minutes to obtain a suspension, the solid content of the suspension was 50wt%;

[0027] 2) Evenly coat the prepared suspension on the porous flexible substrate to form a coating. The coating thickness of the coating is 10 μm, and the porous flexible substrate is a polyolefin porous film;

[0028] 3) Heat and dry the porous flexible substrate coated with the coating at 90°C until the solvent content of the coating is 15wt%, and then roll the coating, and the rolling strength is 120 N / cm 2 , and then continue to bake at 130° C. until completely dry to obtain a lithiu...

Embodiment 3

[0031] The preparation method of the lithium-ion battery diaphragm of the present embodiment is as follows:

[0032] 1) Take a certain amount of N,N-dimethylformamide and add it to the container, heat it to 90°C, add 60 parts of polytetrafluoroethylene and stir until it is completely dissolved, then add 30 parts of calcium carbonate (with a particle size of 800nm) and 0.1 part polyethylene glycol, and continued stirring for 90 minutes to obtain a suspension, the solid content of the suspension was 65wt%;

[0033] 2) Coat the prepared suspension evenly on the porous flexible substrate to form a coating. The coating thickness of the coating is 5 μm, and the porous flexible substrate is a polyolefin porous film;

[0034] 3) Heat and dry the porous flexible substrate coated with the coating at 130°C until the solvent content of the coating is 20wt%, and then roll the coating, and the rolling strength is 30 N / cm 2 , and then continue to bake at 160°C until completely dry to obtain...

technical field

[0001] The invention relates to a preparation method of a lithium ion battery diaphragm. Background technique

[0002] Lithium-ion batteries have the characteristics of long cycle life, high specific energy, good safety performance, small size, light weight, and no memory. They are widely used in mobile phones, notebook computers and other fields. Lithium-ion batteries generally adopt lamination or winding The positive and negative electrodes are separated by a diaphragm during the lamination or winding process to prevent direct electronic pathways between the positive and negative electrodes, and at the same time require the ions in the electrolyte where the positive and negative electrodes are located to freely pass through the diaphragm , to form an ionic current, so the separator is required to have good electrical insulation and a microporous structure that allows ions to pass through. The current separator is made by coating a coating composition on a ...

Examples

Embodiment 1

[0019] The preparation method of the lithium-ion battery diaphragm of the present embodiment is as follows:

[0020] 1) Add a certain amount of N-methylpyrrolidone into the container, heat to 90°C, add 10 parts of polyvinylidene chloride and stir until completely dissolved, then add 10 parts of aluminum oxide (particle size is 10nm), and continue stirring for 90 minutes Obtain suspension, the solid content of suspension is 35wt%;

[0021] 2) Uniformly coat the prepared suspension on the porous flexible substrate to form a coating. The coating thickness of the coating is 1 μm, and the porous flexible substrate is a polyolefin porous film;

[0022] 3) Heat and dry the porous flexible substrate coated with the coating at 60°C until the solvent content of the coating is 10wt%, and then roll the coating, and the rolling strength is 300 N / cm 2 , and then continue to bake at 100°C until completely dry to obtain a lithium-ion battery separator.

[0023] The lithium-ion battery separ...

Embodiment 2

[0025] The preparation method of the lithium-ion battery diaphragm of the present embodiment is as follows:

[0026] 1) Take a certain amount of N,N-dimethylacrylamide and add it to the container, heat it to 90°C, add 30 parts of polyacrylic acid and stir until completely dissolved, then add 20 parts of zirconia (particle size is 200nm) and 5 parts of polyacrylic acid Vinylpyrrolidone, and continued stirring for 90 minutes to obtain a suspension, the solid content of the suspension was 50wt%;

[0027] 2) Evenly coat the prepared suspension on the porous flexible substrate to form a coating. The coating thickness of the coating is 10 μm, and the porous flexible substrate is a polyolefin porous film;

[0028] 3) Heat and dry the porous flexible substrate coated with the coating at 90°C until the solvent content of the coating is 15wt%, and then roll the coating, and the rolling strength is 120 N / cm 2 , and then continue to bake at 130° C. until completely dry to obtain a lithiu...

Embodiment 3

[0031] The preparation method of the lithium-ion battery diaphragm of the present embodiment is as follows:

[0032] 1) Take a certain amount of N,N-dimethylformamide and add it to the container, heat it to 90°C, add 60 parts of polytetrafluoroethylene and stir until it is completely dissolved, then add 30 parts of calcium carbonate (with a particle size of 800nm) and 0.1 part polyethylene glycol, and continued stirring for 90 minutes to obtain a suspension, the solid content of the suspension was 65wt%;

[0033] 2) Coat the prepared suspension evenly on the porous flexible substrate to form a coating. The coating thickness of the coating is 5 μm, and the porous flexible substrate is a polyolefin porous film;

[0034] 3) Heat and dry the porous flexible substrate coated with the coating at 130°C until the solvent content of the coating is 20wt%, and then roll the coating, and the rolling strength is 30 N / cm 2 , and then continue to bake at 160°C until completely dry to obtain...