CN111146426A - Compounding method of lithium ion battery electrode active material - Google Patents

Abstract

The invention discloses a compounding method of an electrode active material of a lithium ion battery, which comprises the following steps of S1, mixing active substances A and A B into a solvent, and fully stirring to form a suspension A; s2, spraying the suspension A into the active substance B in a mixer, and keeping the mixing operation; s3, under the action of a liquid phase, the substances to be compounded are fully and uniformly mixed and firmly bonded; s4, fully stirring and drying, and baking the mixture at 100-200 ℃ to obtain the composite material. The invention adopts a compounding mode of drying and shaping the active substance A and the active substance B after wet spraying, so that the materials to be compounded can be effectively compounded even if the proportion and the characters are greatly different, and a good compounding effect is achieved. The composite components are uniform and stable, and can not deviate due to physical stirring during size mixing and coating. The composite calcination process is avoided, and the damage of the calcination process to the performance of the composite material is reduced.

Description

Compounding method of lithium ion battery electrode active material

Technical Field

The invention relates to a compounding method of an electrode active material of a lithium ion battery.

Background

As an energy storage component of clean energy, a lithium ion battery is widely applied to a plurality of fields such as electric automobiles, electric bicycles, electric tools, digital products, mobile power supplies, energy storage batteries and the like. Lithium batteries are mainly composed of four major parts, namely, electrodes, electrolyte, a battery case and electrode terminals, as chemical power sources. The electrode is used as a key part of a lithium battery and comprises an electrode active material (a positive electrode active material mainstream comprises lithium cobaltate, lithium nickelate, lithium manganate, lithium iron phosphate and lithium nickel cobalt manganese, a negative electrode active material mainstream comprises natural graphite, artificial graphite, silicon carbide material and the like), a conductive agent, colloid and a current collector (generally, an aluminum foil is used as the positive electrode, and a uranium foil is used as the negative electrode). At present, the mainstream manufacturing process adopts size mixing coating process to produce. The positive and negative electrode active materials and other additive materials such as conductive agent are fully and uniformly dispersed in the colloidal solution to form a certain viscosity and solid content, so that the slurry is conveniently coated on a current collector, the residual solvent is dried, and the positive and negative electrodes are prepared by rolling and cutting.

Because the anode and cathode materials which can be used as electrode active materials have more types and have advantages and disadvantages, in some application occasions, two or more anode and cathode materials are required to be compounded together for use, thereby playing a role of mutual complementation. For example: the lithium iron phosphate material with a certain proportion is compounded in the nickel cobalt lithium manganate, so that the cycling stability of the lithium iron phosphate material can be obviously improved compared with that of the lithium iron phosphate material singly used, and the rate capability is obviously improved. The nickel cobalt lithium manganate material with a certain proportion is compounded in the lithium manganate material, so that the dissolution of manganese in high-temperature circulation can be remarkably reduced, and the high-temperature performance of the lithium manganate material is improved. Different compounding modes can produce different effects, and the method is a new technical route in the production of lithium ion batteries.

The electrode material compounding method mainly comprises two methods, one method is that two or more active substances are uniformly mixed in a colloidal solution when electrode slurry is prepared, and then the mixture is uniformly coated on a current collector to achieve the compounding purpose; the other is that when the electrode material is manufactured, the material to be compounded is mixed according to the compounding proportion, is evenly mixed in a mechanical mixing mode and is calcined at low temperature to form the electrode material; the temperature range for calcination is typically 400-600 degrees celsius, because too low a temperature can result in weak composite bonding, and too high a temperature can result in significant changes in the electrochemical properties of the active material.

The method of mixing during slurry mixing can achieve the effect of uniform mixing only when the physical properties of the two materials are not greatly different, but when the physical properties of the two active substances are greatly different or the mixing ratio is greatly different, the mixing effect is greatly reduced, the performance of the composite electrode material is deteriorated, and the purpose of compounding cannot be achieved. The electrode material compounded by the method of mixing two or more active substances firstly and then calcining is adopted, and because the mechanical mixing process is adopted, the uniform mixing of ion level can not be achieved, so that the compounding effect of the material is poor; on the other hand, due to the existence of the calcination process, two different active materials generate a certain degree of sintering reaction, and the electrochemical performance of the active materials is deteriorated to a certain degree. Therefore, the two combined methods cannot achieve the good effect of the laboratory samples in batch production.

Disclosure of Invention

The invention aims to overcome the defects of the prior art and provides a compounding method of an electrode active material of a lithium ion battery.

In order to solve the technical problems, the invention provides the following technical scheme:

the invention discloses a compounding method of an electrode active material of a lithium ion battery, which comprises the following steps:

s1, mixing the active substances A and A B in a solvent, and fully stirring to form a suspension A;

s2, spraying the suspension A into the active substance B in a mixer, and keeping the mixing operation;

s3, under the action of a liquid phase, the substances to be compounded are fully and uniformly mixed and firmly bonded;

s4, fully stirring and drying, and baking the mixture at 100-200 ℃ to obtain the composite material.

The invention adopts a compound mode of drying and shaping after wet spraying of the active substance A and the active substance B, and has the following beneficial effects:

1) and even if the proportion and the characters of the materials to be compounded are greatly different, the materials can be effectively compounded, so that a good compounding effect is achieved.

2) The composite components are uniform and stable, and can not deviate due to physical stirring during size mixing and coating.

3) The composite calcination process is avoided, and the damage of the calcination process to the performance of the composite material is reduced.

4) The process is convenient to carry out, easy to realize and lower in cost compared with a mechanical mixing and calcining method.

Drawings

The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the principles of the invention and not to limit the invention. In the drawings:

FIG. 1 is an SEM image of a composite material of example 1 of the present invention;

FIG. 2 is a comparison of material cycles after non-compounding and different methods of compounding;

FIG. 3 is an SEM image of a composite material prepared by a conventional method;

FIG. 4 is an SEM photograph of a material B to be compounded in example 1 of the present invention.

Detailed Description

The preferred embodiments of the present invention will be described in conjunction with the accompanying drawings, and it will be understood that they are described herein for the purpose of illustration and explanation and not limitation.

Example 1

2% lithium iron phosphate composite 98% nickel cobalt lithium manganate

A. Taking lithium iron phosphate and nickel cobalt lithium manganate in a mass part ratio of 2: 98, preparing materials for standby;

B. mixing the lithium iron phosphate with deionized water in a ratio of 1: 1, uniformly mixing to obtain a lithium iron phosphate suspension; spraying the turbid liquid into the nickel cobalt lithium manganate in a stirrer, and stirring to uniformly distribute the turbid liquid;

C. and (3) baking the uniformly mixed material at 120-180 ℃ for 2-4 hours to obtain the composite material.

Example 2

10% of nickel cobalt lithium manganate composite 90% of lithium manganate

A. Taking nickel cobalt lithium manganate and lithium manganate in a mass part ratio of 1: 9, preparing materials for standby;

B. mixing the nickel cobalt lithium manganate with deionized water in a ratio of 1: 1, uniformly mixing to obtain the nickel cobalt lithium manganate suspension. Spraying the turbid liquid into lithium manganate in a stirrer, and stirring to uniformly distribute the turbid liquid;

C. and (3) baking the uniformly mixed material at 120-180 ℃ for 2-4 hours to obtain the composite material.

FIG. 1 is an SEM image of a composite material of example 1 of the present invention; FIG. 2 is a comparison of material cycles after non-compounding and different methods of compounding; FIG. 3 is an SEM image of a composite material prepared by a conventional method; FIG. 4 is an SEM photograph of a material B to be compounded in example 1 of the present invention.

It can be seen that: the materials to be compounded can be effectively compounded even if the proportion and the characters are greatly different, so that a good compounding effect is achieved; the composite material has uniform and stable composite components, can not deviate due to physical stirring during size mixing and coating, avoids the process of composite calcination, reduces the damage of the calcination process to the performance of the composite material, and has the advantages of convenient process, easy realization and lower cost compared with a mechanical mixing calcination method.

Finally, it should be noted that: although the present invention has been described in detail with reference to the foregoing embodiments, it will be apparent to those skilled in the art that changes may be made in the embodiments and/or equivalents thereof without departing from the spirit and scope of the invention. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims (1)

1. A compounding method of an electrode active material of a lithium ion battery is characterized by comprising the following steps:

s1, mixing the active substances A and A B in a solvent, and fully stirring to form a suspension A;

s2, spraying the suspension A into the active substance B in a mixer, and keeping the mixing operation;

s3, under the action of a liquid phase, the substances to be compounded are fully and uniformly mixed and firmly bonded;

s4, fully stirring and drying, and baking the mixture at 100-200 ℃ to obtain the composite material.

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