A kind of lithium ion battery and preparation method thereof

Abstract

The invention provides a lithium ion battery and a preparation method thereof. The lithium-ion battery comprises a casing and an electrode group and an electrolyte sealed in the casing, the electrode group includes a positive pole, a negative pole and a diaphragm between the positive pole and the negative pole, and a porous layer is contained between the negative pole and the diaphragm, so The porous layer includes ceramic particles and a binder, the ceramic particles include aluminum oxide and silicon oxide, based on the mass percentage of the ceramic particles, the content of the aluminum oxide is 70-90wt%, and the content of the silicon oxide The content is 10-30wt%, the average particle size of the alumina particles is 200nm-700nm, the average particle size of the silicon oxide particles is 200nm-500nm, the prepared battery has good rate charge and discharge characteristics, high temperature cycle capacity retention rate, The high-temperature storage performance of the battery is excellent and the safety performance is more ideal.

Description

technical field

[0001] The invention relates to the field of batteries, in particular, the invention relates to a lithium ion battery and a preparation method thereof. Background technique

[0002] Lithium-ion batteries are currently widely used secondary batteries, which have the advantages of high specific energy, high working voltage, low self-discharge rate, long cycle life, and no pollution. Widely used in electric tools, electric vehicles and other fields, there are important requirements for its safety performance.

[0003] When the lithium-ion battery is stored in an extremely high temperature environment for a long time or under long-term use or abuse, the separator is easy to shrink or be destroyed, and the positive and negative electrodes will actually contact each other to generate an internal short circuit. The trend of lithium-ion battery capacity also has the risk of lithium dendrites piercing the diaphragm. Once an internal short circuit occurs, the battery ...

Examples

preparation example Construction

[0020] The present invention also provides a preparation method for the above-mentioned battery, the steps include: S1, preparation of the electrode group: the negative electrode / diaphragm / positive electrode is wound or stacked to prepare the electrode group, wherein a porous layer is also separated between the negative electrode and the diaphragm, The porous layer includes ceramic particles and a binder, the ceramic particles include aluminum oxide and silicon oxide, based on the mass percentage of the ceramic particles, the content of the aluminum oxide is 70-90wt%, and the silicon oxide The content of the aluminum oxide is 10-30wt%, the average particle size of the aluminum oxide particles is 200nm-700nm, the average particle size of the silicon oxide particles is 200nm-500nm, and the above-mentioned ceramic particles can be obtained commercially. The method for forming the electrode group by winding or stacking has no special requirements in the present invention, and can b...

Embodiment 1

[0056] (1) Preparation of negative electrode sheet

[0057] Mix and stir 100 grams of water and 1 gram of CMC2000 (sodium hydroxymethyl cellulose 2000) until the viscosity of the mixed solution changes less than 3% within 10 minutes, then add 3 grams of microspherical superconducting carbon black with a particle size of 6.5 μm Stir until the viscosity of the mixture changes less than 3% within 10 minutes, then add 70 grams of natural graphite and stir for 1 hour until the viscosity of the mixture changes less than 5%, and finally add 2.5 grams of BM400 (styrene-butadiene rubber) and stir until uniform to obtain a negative electrode slurry. The negative electrode slurry is evenly coated on a copper foil with a width of 400 mm and a thickness of 10 microns, with a coating thickness of 140 microns, vacuum-dried at 100 ° C for 5 hours, and after rolling, it is cut on a slitting machine to obtain a size of 544 mm. mm x 45 mm x 105 µm for the negative electrode.

[0058] (2) Prepar...

Embodiment 2

[0068] (1) Preparation of negative electrode sheet

[0069] Mix and stir 100 grams of water and 1 gram of CMC2000 (sodium hydroxymethyl cellulose 2000) until the viscosity of the mixed solution changes less than 3% within 10 minutes, then add 3 grams of microspherical superconducting carbon black with a particle size of 6.5 μm Stir until the viscosity of the mixture changes less than 3% within 10 minutes, then add 70 grams of natural graphite and stir for 1 hour until the viscosity of the mixture changes less than 5%, and finally add 2.5 grams of BM400 (styrene-butadiene rubber) and stir until uniform to obtain a negative electrode slurry. The negative electrode slurry is evenly coated on a copper foil with a width of 400 mm and a thickness of 10 microns, with a coating thickness of 140 microns, vacuum-dried at 100 ° C for 5 hours, and after rolling, it is cut on a slitting machine to obtain a size of 544 mm. mm x 45 mm x 105 µm for the negative electrode.

[0070] (2) Prepar...

technical field

[0001] The invention relates to the field of batteries, in particular, the invention relates to a lithium ion battery and a preparation method thereof. Background technique

[0002] Lithium-ion batteries are currently widely used secondary batteries, which have the advantages of high specific energy, high working voltage, low self-discharge rate, long cycle life, and no pollution. Widely used in electric tools, electric vehicles and other fields, there are important requirements for its safety performance.

[0003] When the lithium-ion battery is stored in an extremely high temperature environment for a long time or under long-term use or abuse, the separator is easy to shrink or be destroyed, and the positive and negative electrodes will actually contact each other to generate an internal short circuit. The trend of lithium-ion battery capacity also has the risk of lithium dendrites piercing the diaphragm. Once an internal short circuit occurs, the battery ...

Examples

preparation example Construction

[0020] The present invention also provides a preparation method for the above-mentioned battery, the steps include: S1, preparation of the electrode group: the negative electrode / diaphragm / positive electrode is wound or stacked to prepare the electrode group, wherein a porous layer is also separated between the negative electrode and the diaphragm, The porous layer includes ceramic particles and a binder, the ceramic particles include aluminum oxide and silicon oxide, based on the mass percentage of the ceramic particles, the content of the aluminum oxide is 70-90wt%, and the silicon oxide The content of the aluminum oxide is 10-30wt%, the average particle size of the aluminum oxide particles is 200nm-700nm, the average particle size of the silicon oxide particles is 200nm-500nm, and the above-mentioned ceramic particles can be obtained commercially. The method for forming the electrode group by winding or stacking has no special requirements in the present invention, and can b...

Embodiment 1

[0056] (1) Preparation of negative electrode sheet

[0057] Mix and stir 100 grams of water and 1 gram of CMC2000 (sodium hydroxymethyl cellulose 2000) until the viscosity of the mixed solution changes less than 3% within 10 minutes, then add 3 grams of microspherical superconducting carbon black with a particle size of 6.5 μm Stir until the viscosity of the mixture changes less than 3% within 10 minutes, then add 70 grams of natural graphite and stir for 1 hour until the viscosity of the mixture changes less than 5%, and finally add 2.5 grams of BM400 (styrene-butadiene rubber) and stir until uniform to obtain a negative electrode slurry. The negative electrode slurry is evenly coated on a copper foil with a width of 400 mm and a thickness of 10 microns, with a coating thickness of 140 microns, vacuum-dried at 100 ° C for 5 hours, and after rolling, it is cut on a slitting machine to obtain a size of 544 mm. mm x 45 mm x 105 µm for the negative electrode.

[0058] (2) Prepar...

Embodiment 2

[0068] (1) Preparation of negative electrode sheet

[0069] Mix and stir 100 grams of water and 1 gram of CMC2000 (sodium hydroxymethyl cellulose 2000) until the viscosity of the mixed solution changes less than 3% within 10 minutes, then add 3 grams of microspherical superconducting carbon black with a particle size of 6.5 μm Stir until the viscosity of the mixture changes less than 3% within 10 minutes, then add 70 grams of natural graphite and stir for 1 hour until the viscosity of the mixture changes less than 5%, and finally add 2.5 grams of BM400 (styrene-butadiene rubber) and stir until uniform to obtain a negative electrode slurry. The negative electrode slurry is evenly coated on a copper foil with a width of 400 mm and a thickness of 10 microns, with a coating thickness of 140 microns, vacuum-dried at 100 ° C for 5 hours, and after rolling, it is cut on a slitting machine to obtain a size of 544 mm. mm x 45 mm x 105 µm for the negative electrode.

[0070] (2) Prepar...