Positive plate, preparation method thereof and lithium ion battery

Abstract

The invention provides a positive plate, a preparation method thereof and a lithium ion battery. The method comprises the following steps: 1) mixing a conductive agent composite positive electrode material, a binder and a solvent to obtain positive electrode slurry; and 2) coating the surface of a current collector with the positive electrode slurry, and carrying out cold pressing treatment to obtain the positive plate. According to the preparation method of the positive plate provided by the invention, the conductive agent is compounded with the positive electrode material, the positive electrode material and the conductive agent are combined, no additional conductive agent needs to be added in the process of mixing to form slurry, the stirring process can be greatly simplified, only one-step charging and stirring process is needed, the stirring time is shortened, the positive plate production efficiency is improved, and the production cost is reduced. Meanwhile, the conductive agentis used for compounding the positive electrode material instead of being added in the process of mixing the slurry, so that local agglomeration caused by non-uniform dispersion of the conductive agentin the stirring process can be prevented, the consistency of slurry dispersion is ensured, the coating effect of the positive electrode piece is improved, and the consistency of the battery is further improved.

Description

technical field

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

[0002] With the social development and the increasingly serious environmental pollution problems, the development of new energy has attracted more and more attention. Lithium-ion batteries have become one of the research hotspots of scientific researchers in recent years, and the cathode materials of lithium-ion batteries are the focus of people's attention. . At present, the positive electrode materials used in commercial lithium-ion batteries mainly include LiCoO 2 , lithium nickelate, nickel-cobalt lithium manganate ternary materials and lithium iron phosphate, etc. At present, the positive electrode materials of power batteries used in new energy vehicles in the market are mainly NCM ternary mate...

Examples

Embodiment 1

[0064] In this embodiment, the positive electrode sheet is prepared according to the following method:

[0065] (1) Conducting agent composite positive electrode material, binder PVDF and solvent NMP (without adding conductive agent, taking the total mass of conductive agent composite positive electrode material and binder as 100%, the mass fraction of binder is 1% , the mass fraction of the conductive agent composite positive electrode material is 99%) and stirred and mixed at 45°C for 3h to obtain a positive electrode slurry with a solid content of 60% and a viscosity of 15000mPa·s;

[0066] (2) Coating the positive electrode slurry described in step (1) on the surface of the current collector aluminum foil, after drying, cold pressing at a temperature of 25°C and a pressure of 30t to obtain the positive electrode sheet;

[0067] The pressing method of the cold pressing treatment is rolling, and the size of the roll gap is 120 μm.

[0068] In this embodiment, the conductive...

Embodiment 2

[0075] In this embodiment, the positive electrode sheet is prepared according to the following method:

[0076] (1) Composite positive electrode material with conductive agent, binder PVDF and solvent NMP (do not add conductive agent, take the total mass of conductive agent composite positive electrode material and binder as 100%, and the mass fraction of binder is 0.5% , the mass fraction of the conductive agent composite positive electrode material is 99.5%) and stirred and mixed for 5 hours at 25°C to obtain a positive electrode slurry with a solid content of 50% and a viscosity of 8000mPa·s;

[0077] (2) coating the positive electrode slurry described in step (1) on the surface of the current collector aluminum foil, after drying, cold pressing at a temperature of 15° C. and a pressure of 10 tons to obtain the positive electrode sheet;

[0078] The pressing method of the cold pressing treatment is rolling, and the size of the roll gap is 50 μm.

[0079] The conductive age...

Embodiment 3

[0081] In this embodiment, the positive electrode sheet is prepared according to the following method:

[0082] (1) Composite positive electrode material with conductive agent, binder PVDF and solvent NMP (do not add conductive agent, take the total mass of conductive agent composite positive electrode material and binder as 100%, and the mass fraction of binder is 5% , the mass fraction of the conductive agent composite positive electrode material is 95%) and stirred and mixed at 60°C for 2h to obtain a positive electrode slurry with a solid content of 70% and a viscosity of 25000mPa·s;

[0083] (2) Coating the positive electrode slurry described in step (1) on the surface of the current collector aluminum foil, after drying, cold pressing at a temperature of 35° C. and a pressure of 50 tons to obtain the positive electrode sheet;

[0084] The pressing method of the cold pressing treatment is rolling, and the size of the roll gap is 200 μm.

[0085] The conductive agent comp...

technical field

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

[0002] With the social development and the increasingly serious environmental pollution problems, the development of new energy has attracted more and more attention. Lithium-ion batteries have become one of the research hotspots of scientific researchers in recent years, and the cathode materials of lithium-ion batteries are the focus of people's attention. . At present, the positive electrode materials used in commercial lithium-ion batteries mainly include LiCoO 2 , lithium nickelate, nickel-cobalt lithium manganate ternary materials and lithium iron phosphate, etc. At present, the positive electrode materials of power batteries used in new energy vehicles in the market are mainly NCM ternary mate...

Examples

Embodiment 1

[0064] In this embodiment, the positive electrode sheet is prepared according to the following method:

[0065] (1) Conducting agent composite positive electrode material, binder PVDF and solvent NMP (without adding conductive agent, taking the total mass of conductive agent composite positive electrode material and binder as 100%, the mass fraction of binder is 1% , the mass fraction of the conductive agent composite positive electrode material is 99%) and stirred and mixed at 45°C for 3h to obtain a positive electrode slurry with a solid content of 60% and a viscosity of 15000mPa·s;

[0066] (2) Coating the positive electrode slurry described in step (1) on the surface of the current collector aluminum foil, after drying, cold pressing at a temperature of 25°C and a pressure of 30t to obtain the positive electrode sheet;

[0067] The pressing method of the cold pressing treatment is rolling, and the size of the roll gap is 120 μm.

[0068] In this embodiment, the conductive...

Embodiment 2

[0075] In this embodiment, the positive electrode sheet is prepared according to the following method:

[0076] (1) Composite positive electrode material with conductive agent, binder PVDF and solvent NMP (do not add conductive agent, take the total mass of conductive agent composite positive electrode material and binder as 100%, and the mass fraction of binder is 0.5% , the mass fraction of the conductive agent composite positive electrode material is 99.5%) and stirred and mixed for 5 hours at 25°C to obtain a positive electrode slurry with a solid content of 50% and a viscosity of 8000mPa·s;

[0077] (2) coating the positive electrode slurry described in step (1) on the surface of the current collector aluminum foil, after drying, cold pressing at a temperature of 15° C. and a pressure of 10 tons to obtain the positive electrode sheet;

[0078] The pressing method of the cold pressing treatment is rolling, and the size of the roll gap is 50 μm.

[0079] The conductive age...

Embodiment 3

[0081] In this embodiment, the positive electrode sheet is prepared according to the following method:

[0082] (1) Composite positive electrode material with conductive agent, binder PVDF and solvent NMP (do not add conductive agent, take the total mass of conductive agent composite positive electrode material and binder as 100%, and the mass fraction of binder is 5% , the mass fraction of the conductive agent composite positive electrode material is 95%) and stirred and mixed at 60°C for 2h to obtain a positive electrode slurry with a solid content of 70% and a viscosity of 25000mPa·s;

[0083] (2) Coating the positive electrode slurry described in step (1) on the surface of the current collector aluminum foil, after drying, cold pressing at a temperature of 35° C. and a pressure of 50 tons to obtain the positive electrode sheet;

[0084] The pressing method of the cold pressing treatment is rolling, and the size of the roll gap is 200 μm.

[0085] The conductive agent comp...

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