阅读说明：本技术 一种锂离子电池负极石墨回收利用的方法 (Method for recycling graphite of negative electrode of lithium ion battery ) 是由 艾戊云 孔令超 袁海中 于 2020-06-05 设计创作，主要内容包括：本发明属于电池技术领域,具体涉及一种锂离子电池负极石墨回收利用的方法,包括如下步骤：S1、收集废旧的负极极片；S2、对负极极片进行鉴别筛选；S3、用粉碎机对负极极片进行粉碎；S4、用石墨球形化设备对粉碎后的粉末进行球形化；S5、对球形化的粉末进行筛分,去除粉体中的大部分磁性及金属异物；S6、对筛分后的粉末进行石墨化；S7、对石墨粉进行包覆；S8、对包覆后的石墨粉进行炭化热处理；S9、对炭化后的石墨粉再一次进行除磁筛分,进一步地去除粉体中的微量的磁性及金属异物,提高石墨的纯度。该方法对废旧负极材料中石墨的再利用率高,生产出来的负极材料中石墨的纯度高,有效地减少了资源浪费,提高了回收利用的效率。(The invention belongs to the technical field of batteries, and particularly relates to a method for recycling graphite of a lithium ion battery cathode, which comprises the following steps: s1, collecting waste negative pole pieces; s2, identifying and screening the negative pole piece; s3, crushing the negative pole piece by using a crusher; s4, spheroidizing the crushed powder by graphite spheroidizing equipment; s5, screening the spherical powder to remove most of magnetic and metallic foreign matters in the powder; s6, graphitizing the sieved powder; s7, coating the graphite powder; s8, carrying out carbonization heat treatment on the coated graphite powder; and S9, demagnetizing and screening the carbonized graphite powder again to further remove trace magnetic and metal foreign matters in the powder and improve the purity of the graphite. The method has the advantages that the recycling rate of the graphite in the waste negative electrode material is high, the purity of the graphite in the produced negative electrode material is high, the resource waste is effectively reduced, and the recycling efficiency is improved.)

1. A method for recycling graphite of a negative electrode of a lithium ion battery is characterized by comprising the following steps:

s1, collecting waste negative pole pieces;

s2, identifying and screening the negative pole piece;

s3, crushing the negative pole piece by using a crusher;

s4, spheroidizing the crushed powder by graphite spheroidizing equipment;

s5, screening the spherical powder to remove most of magnetic and metallic foreign matters in the powder;

s6, graphitizing the sieved powder;

s7, coating the graphite powder;

s8, carrying out carbonization heat treatment on the coated graphite powder;

s9, demagnetizing and screening the carbonized graphite powder again to further remove trace magnetic and metal foreign matters in the powder and improve the purity of graphite;

and S10, using the obtained high-purity graphite powder in the preparation of the cathode material.

2. The method for recycling graphite of a negative electrode of a lithium ion battery according to claim 1, wherein: in step S1, the waste negative electrode plate is from the scrap paper generated in the production process or the scrap paper generated in the use process.

3. The method for recycling graphite of a negative electrode of a lithium ion battery according to claim 1, wherein: in step S2, the negative electrode tab is separated from the battery.

4. The method for recycling graphite of a negative electrode of a lithium ion battery according to claim 1, wherein: in step S3, the pulverizer pulverizes the negative electrode tab into powder.

5. The method for recycling graphite for negative electrodes of lithium ion batteries according to claim 1, wherein step S3 specifically includes the steps of:

t1, roughly crushing the negative pole piece;

t2, drying the coarsely crushed negative pole piece;

t3, crushing the dried negative pole piece;

t4, kneading and removing powder from the crushed material;

t5, mechanically crushing;

t6, classifying the crushed product.

6. The method for recycling graphite of a negative electrode of a lithium ion battery according to claim 5, wherein: in step T6, the material is pulverized and classified by an ultrafine pulverizing classifier.

7. The method for recycling graphite of a negative electrode of a lithium ion battery according to claim 1, wherein: in step S6, the temperature at which the powder is graphitized is controlled to 2800 ℃ to 3000 ℃.

8. The method for recycling graphite of a negative electrode of a lithium ion battery according to claim 1, wherein: in step S7, the graphite powder is coated by solid-phase coating or liquid-phase coating.

9. The method for recycling graphite of a negative electrode of a lithium ion battery according to claim 1, wherein: in step S9, the graphite powder is depolymerized before being sieved.

10. The method for recycling graphite of a negative electrode of a lithium ion battery according to claim 1, wherein: in step S10, the graphite powder is used for the preparation of the negative electrode material after going through the steps of degaussing and sieving in sequence.

Technical Field

The invention belongs to the technical field of batteries, and particularly relates to a method for recycling graphite of a negative electrode of a lithium ion battery.

Background

The lithium ion secondary battery is used as a good electric energy carrier, has the advantages of high voltage, large specific capacity, good cyclicity, no memory effect and the like, is widely applied to the fields of electronic products, electric vehicles, aerospace and the like, and becomes one of the best choices for realizing the transition from the traditional fossil fuel to clean, environment-friendly and renewable energy sources. In recent years, with the rapid development of the global lithium ion battery industry, the capacity of the lithium ion battery industry increases year by year, and according to the statistical data of the national statistical bureau, the total output of the lithium ion battery in 2013 is about 47.68 hundred million, which is increased by 16.9% on a par with the total output. In the process of the lithium ion battery industrialized batch production, as the assembly technology is a very complex and strict process, many battery manufacturing enterprises can cause substandard products to appear due to the process errors of slurry stirring, pole piece coating, slitting, pole lug welding, cap sealing and the like, and the reject ratio is about 10-20% of the total production amount, so that the production capacity of the lithium battery continuously rises, and a large amount of corresponding rejected products need to be processed. At present, the recovery of metals in lithium ion batteries has formed an industrialized process flow, mainly the recycling of cobalt, nickel, manganese and other elements in positive electrode materials and copper sheets of negative electrode current collectors, including technologies of mechanical separation, hydrometallurgy, pyrometallurgy and the like, while the recovery technology of negative electrode materials is still imperfect, the negative electrode materials of current commercialized lithium ion batteries of negative electrode materials mainly comprise artificial graphite, natural graphite and various modified graphites, and can only be generally discarded or incinerated at high temperature, but such a method not only aggravates atmospheric dust pollution and greenhouse effect, but also causes a great deal of resource waste. Although graphite is a dominant mineral product in China, the resource is rich, the cost is low, the grade of the graphite ore is low, generally below 10%, and the preparation process from the mineral source to the cathode material has long period, large energy consumption and low recovery rate, thus causing the situation of long-term short supply and short demand in the market. The graphite content of the negative electrode resource of the unqualified battery reaches more than 85 percent, the material is subjected to particle modeling, surface oxidation, coating and other treatment, the average mass of the battery is 40 g/piece, the negative electrode material accounts for 13 percent of the weight of the battery, and the annual loss of the negative electrode material discarded along with the unqualified battery is close to 0.4 ten thousand tons by 2013. Therefore, if the negative electrode resources of the unqualified batteries can be recycled, the shortage of supply can be relieved to a certain extent, a large amount of graphite mineral resources and mining cost can be saved, the production energy consumption can be reduced, and the ecological environment can be protected.

Disclosure of Invention

The invention aims to: aiming at the defects of the prior art, the method for recycling the negative electrode graphite of the lithium ion battery is also provided, the recycling rate of the graphite in the waste negative electrode material is high, the purity of the graphite in the produced negative electrode material is high, the resource waste is effectively reduced, and the recycling efficiency is improved.

In order to achieve the purpose, the invention provides a method for recycling graphite of a negative electrode of a lithium ion battery, which comprises the following steps:

s1, collecting waste negative pole pieces;

s2, identifying and screening the negative pole piece; in practical application, a general method is that lithium ion battery recycling enterprises should identify the types of batteries according to manufacturers, labels, shell materials, shapes, weights, components and the like of the lithium ion batteries, and then identify the types of graphite or confirm the types of the graphite through electrochemical detection; the special method is that the waste lithium ion battery with incomplete label or the category and the components of the battery which can not be confirmed from the appearance of the battery is identified according to the following method: taking a negative plate of the waste lithium ion battery, hydrolyzing and drying graphite of the negative plate, and judging according to the granularity, the graphitization degree, the SEM topography and the like;

s3, crushing the negative pole piece by using a crusher;

s4, spheroidizing the crushed powder by graphite spheroidizing equipment;

s5, screening the spherical powder to remove most of magnetic and metallic foreign matters in the powder;

s6, graphitizing the sieved powder;

s7, coating the graphite powder;

s8, carrying out carbonization heat treatment on the coated graphite powder;

s9, demagnetizing and screening the carbonized graphite powder again to further remove trace magnetic and metal foreign matters in the powder and improve the purity of graphite;

and S10, using the obtained high-purity graphite powder in the preparation of the cathode material. In production, after screening out the negative pole piece on the battery, crushing the whole negative pole piece, and then carrying out spheroidization treatment, in the existing production technology, the graphite on the negative pole material is separated from the current collector firstly, and then the graphite is recycled, the existing technology cannot ensure that the graphite on the current collector is completely separated, and cannot realize the full reutilization of the graphite, but the technical scheme in the application not only realizes the full utilization of the original graphite on the current collector, but also can graphitize the non-metallic material on the current collector, thereby improving the capacity of recovering the graphite; in addition, the graphite powder is subjected to multiple heating treatments and screening in the technical scheme, so that the precision of the graphite powder is improved. The method has the advantages that the recycling rate of the graphite in the waste negative electrode material is high, the purity of the graphite in the produced negative electrode material is high, the resource waste is effectively reduced, and the recycling efficiency is improved.

As an improvement of the method for recycling the negative graphite of the lithium ion battery, in step S1, the waste negative electrode plate comes from waste products generated in the production process or waste products generated in the use process.

As an improvement of the method for recycling graphite of the negative electrode of the lithium ion battery, in step S2, the negative electrode sheet is separated from the battery.

As an improvement of the method for recycling graphite of a negative electrode of a lithium ion battery according to the present invention, in step S3, a pulverizer pulverizes a negative electrode sheet into powder.

As an improvement of the method for recycling graphite for a negative electrode of a lithium ion battery according to the present invention, in step S3, the method specifically includes the following steps:

t1, roughly crushing the negative pole piece;

t2, drying the coarsely crushed negative pole piece;

t3, crushing the dried negative pole piece;

t4, kneading and removing powder from the crushed material; in practical application, the negative plate is crushed to produce copper powder and graphite powder, and the copper powder and the graphite powder are classified according to the required ingredients;

t5, mechanically crushing; in practical application, metal and nonmetal in the negative electrode material are separated through chemical reaction, so that the yield of graphite is increased;

t6, classifying the crushed product.

In an improvement of the method for recycling graphite for a negative electrode of a lithium ion battery according to the present invention, in step T6, a micronizing classifier is used to perform pulverization and classification.

As an improvement of the method for recycling graphite of the negative electrode of the lithium ion battery, in step S6, the temperature for graphitizing the powder is controlled to 2800-3000 ℃. In practical applications, the higher the temperature, the shorter the time for high temperature and constant temperature required for processing.

As an improvement of the method for recycling graphite for a negative electrode of a lithium ion battery according to the present invention, in step S7, the graphite powder is coated in a solid-phase coating or a liquid-phase coating.

As an improvement of the method for recycling graphite for a negative electrode of a lithium ion battery according to the present invention, in step S9, the graphite powder is depolymerized before being sieved.

As an improvement of the method for recycling graphite of the negative electrode of the lithium ion battery, in step S10, graphite powder is used for preparing a negative electrode material after sequentially going through the steps of demagnetizing and sieving.

Compared with the prior art, the invention has the beneficial effects that: in production, after screening out the negative pole piece on the battery, crushing the whole negative pole piece, and then performing spheroidization treatment to repair the surface appearance of the material, in the existing production technology, the graphite on the negative pole material is separated from the current collector firstly, and then the graphite is recycled, the existing technology cannot ensure that the graphite on the current collector is completely separated, and cannot realize the full recycling of the graphite, and the technical scheme in the application not only realizes the full utilization of the original graphite on the current collector, but also can graphitize the non-metallic material on the current collector, thereby improving the productivity of recovering the graphite; in addition, in the technical scheme, the graphite is subjected to multiple heating treatments and screening, so that the purity of the graphite powder is improved. The method has the advantages that the recycling rate of the graphite in the waste negative electrode material is high, the purity of the graphite in the produced negative electrode material is high, the resource waste is effectively reduced, and the recycling efficiency is improved.

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 invention and not to limit the invention. In the drawings:

FIG. 1 is a flow chart in an embodiment of the invention;

FIG. 2 is an electron micrograph of the powder before spheroidization in step S4 according to the embodiment of the present invention;

FIG. 3 is an electron micrograph of the powder after spheroidizing in step S4 according to the embodiment of the present invention;

FIG. 4 is a report of XRD test of the powder before high temperature graphitization in step S6 according to the present invention;

FIG. 5 is a report of XRD test of the powder after high temperature graphitization in step S6 according to the present invention;

FIG. 6 is a report of XRD testing after the powder is sieved again in step S9 according to an embodiment of the present invention;

fig. 7 is a chart of electrical performance cycles of the negative electrode material at 45 ℃ in step S10 according to the embodiment of the present invention.

Detailed Description

As used in the specification and in the claims, certain terms are used to refer to particular components. As one skilled in the art will appreciate, manufacturers may refer to a component by different names. This specification and claims do not intend to distinguish between components that differ in name but not function. In the following description and in the claims, the terms "include" and "comprise" are used in an open-ended fashion, and thus should be interpreted to mean "include, but not limited to. "substantially" means within an acceptable error range, within which a person skilled in the art can solve the technical problem to substantially achieve the technical result.

In the description of the present invention, it is to be understood that the terms "upper", "lower", "front", "rear", "left", "right", "horizontal", and the like indicate orientations or positional relationships based on those shown in the drawings, and are only for convenience in describing the present invention and simplifying the description, but do not indicate or imply that the referred device or element must have a specific orientation, be constructed in a specific orientation, and be operated, and thus, should not be construed as limiting the present invention.

The present invention will be described in further detail below with reference to the accompanying drawings, but the present invention is not limited thereto.