阅读说明：本技术 一种锂离子电池极片的清洗方法 (Method for cleaning lithium ion battery pole piece ) 是由 洪春林 郑松斌 张旭 纪荣进 李聪 郑明清 陈杰 李载波 杨山 于 2020-04-23 设计创作，主要内容包括：本发明属于锂离子电池技术领域,具体涉及一种锂离子电池极片的清洗方法,包括步骤1、将极片放置于涂布机中进行涂布,并利用小功率激光对涂布后的极片上的焊接槽进行初步清洗；步骤2、待初步清洗完成后,将极片过辊进行冷压,使涂布层与极片紧密压实；步骤3、根据电池的尺寸规格,利用分切设备对冷压后的极片进行分切,得到小条的极片；步骤4、对步骤3中得到的极片进行溶剂擦洗。与现有技术相比,本发明通过在冷压前先利用小功率的激光对极片进行初步清洗,清除了焊接槽处的大部分涂布层粉料,有效地减少了对极片的损伤,另外,再通过溶剂擦洗,可以轻松将涂布层粉末清除,显著地提高了清洗的效果,避免了传统的槽位尺寸难以控制的问题。(The invention belongs to the technical field of lithium ion batteries, and particularly relates to a method for cleaning a lithium ion battery pole piece, which comprises the following steps of 1, placing the pole piece in a coating machine for coating, and primarily cleaning a welding groove on the coated pole piece by using low-power laser; step 2, after the preliminary cleaning is finished, cold pressing the pole piece by passing through a roller to tightly compact the coating layer and the pole piece; step 3, cutting the cold-pressed pole piece by using cutting equipment according to the size specification of the battery to obtain a small pole piece; and 4, carrying out solvent scrubbing on the pole piece obtained in the step 3. Compared with the prior art, the pole piece is preliminarily cleaned by using the low-power laser before cold pressing, most of coating layer powder at a welding groove is removed, damage to the pole piece is effectively reduced, in addition, the coating layer powder can be easily removed by solvent scrubbing, the cleaning effect is obviously improved, and the problem that the size of a traditional groove position is difficult to control is solved.)

1. A method for cleaning a lithium ion battery pole piece is characterized by comprising the following steps:

step 1) placing a pole piece in a coating machine for coating, and primarily cleaning a welding groove on the coated pole piece by using low-power laser;

step 2) after the preliminary cleaning is finished, cold pressing the pole piece by passing through a roller to tightly compact the coating layer and the pole piece;

step 3) cutting the cold-pressed pole piece by using cutting equipment according to the size specification of the battery to obtain a small pole piece;

and 4) carrying out solvent scrubbing on the pole piece obtained in the step 3).

2. The method for cleaning the lithium ion battery pole piece according to claim 1, characterized in that: the output power of the laser in the step 1 is 20-90 w.

3. The method for cleaning the lithium ion battery pole piece according to claim 1, characterized in that: the pressure applied by cold pressing in the step 2 is 1-10000 kgf, and the rolling speed is 4-20 m/min.

4. The method for cleaning the lithium ion battery pole piece according to claim 1, characterized in that: the solvent is any one of N-methyl pyrrolidone, absolute ethyl alcohol, butanone, epoxy resin, diethyl carbonate, propylene carbonate, methyl ethyl carbonate, dimethyl carbonate and polypropylene.

5. The method for cleaning the lithium ion battery pole piece according to claim 1, wherein the step 4 of scrubbing the pole piece with the solvent specifically comprises the following steps:

step 4.1) spraying a solvent to the welding groove on one surface of the pole piece, and scrubbing the welding groove sprayed with the solvent by using a wiping device;

step 4.2) after the scrubbing is finished, spraying a solvent on the welding groove on the other surface of the pole piece, and scrubbing the welding groove on the surface by using a scrubbing device;

and 4.3) detecting the scrubbing effect of the pole piece with two scrubbed surfaces through mechanical vision equipment.

6. The method for cleaning the lithium ion battery pole piece according to claim 5, characterized in that: and 4.1, before spraying the solvent on the pole piece, die cutting is carried out on the powder of the coating layer at the edge of the welding groove.

7. The method for cleaning the lithium ion battery pole piece according to claim 5, characterized in that: the wiping device comprises a wiping head and dust-free paper, wherein the wiping head is used for wiping the welding groove, and the dust-free paper is used for cleaning the wiping head.

8. The method for cleaning the lithium ion battery pole piece according to claim 7, characterized in that: the wiping head is made of a mixed material of hard foam and soft foam.

9. The method for cleaning the lithium ion battery pole piece according to claim 5, characterized in that: and (3) absorbing powder of the coating layer falling off in the scrubbing process of the welding groove in the step (4.1) and the step (4.2) by using vacuum absorption equipment.

10. The method for cleaning the lithium ion battery pole piece according to claim 5, characterized in that: the mechanical vision device is a CCD camera or a CMOS camera.

Technical Field

The invention belongs to the technical field of lithium ion batteries, and particularly relates to a method for cleaning a lithium ion battery pole piece.

Background

Lithium ion batteries are widely used in various industries due to their advantages of high operating voltage, high energy density, long cycle life, no memory, etc.

At present, in the production process of lithium ion batteries, after cathode pole pieces are subjected to the processes of coating, cold pressing and splitting, welding grooves on two surfaces of the pole pieces are usually cleaned by one of laser and solvent, so that the welding grooves keep a certain neatness, and the welding effect of the pole pieces and the pole lugs is ensured. However, according to the current technology, the above cleaning method still has certain defects:

1) the mode of using laser to wash the pole piece is as follows: in order to ensure that the cathode plate is cleaned, the laser is usually required to be adjusted to a higher power, and because the aluminum foil melting point of the cathode plate is small and is about 700 ℃, the cathode plate is easy to burn under the irradiation of the high-power laser, so that the aluminum foil is oxidized and even can be perforated to cause light transmission, the impedance of a cleaning area is increased, and the welding effect of the cathode plate and a tab is influenced;

2) the mode of using solvent to wash the pole piece is as follows: after the pole piece is subjected to the cold pressing process, the bonding force between the pole piece and the coating is increased, the coating powder at the welding groove is not easy to scrub, the diffusion range of the solvent is wide, the diffusion speed is high, and the size of a groove position of the welding groove is easy to control during scrubbing.

In view of the above, there is a need for improving the current cleaning scheme of battery pole piece reasonably to meet the actual production requirement.

Disclosure of Invention

The invention aims to: the method for cleaning the lithium ion battery pole piece effectively solves the problems that the pole piece is damaged and the cleaning size is difficult to control in the traditional cleaning mode.

In order to achieve the purpose, the invention adopts the following technical scheme:

a method for cleaning a lithium ion battery pole piece comprises the following steps:

step 1) placing a pole piece in a coating machine for coating, and primarily cleaning a welding groove on the coated pole piece by using low-power laser;

step 2) after the preliminary cleaning is finished, cold pressing the pole piece by passing through a roller to tightly compact the coating layer and the pole piece;

step 3) cutting the cold-pressed pole piece by using cutting equipment according to the size specification of the battery to obtain a small pole piece;

and 4) carrying out solvent scrubbing on the pole piece obtained in the step 3).

As an improvement of the method for cleaning the lithium ion battery pole piece, the output power of the laser in the step 1 is 20-90 w. Through the laser cleaning that adopts the miniwatt, can get rid of most coating layer powder on the pole piece welding groove, do not harm the pole piece foil, in addition, remain after the preliminary washing coating layer powder in welding groove because do not receive the force in follow-up cold pressing process, consequently, this part coating layer powder adhesion is less, and easy subsequent solvent is cleaned to improve the effect of cleaning.

As an improvement of the cleaning method of the lithium ion battery pole piece, the pressure applied by cold pressing in the step 2 is 1-10000 kgf, and the rolling speed is 4-20 m/min.

As an improvement on the cleaning method of the lithium ion battery pole piece, the solvent is any one of N-methyl pyrrolidone, absolute ethyl alcohol, butanone, epoxy resin, diethyl carbonate, propylene carbonate, methyl ethyl carbonate, dimethyl carbonate and polypropylene. Wherein, this solvent can prefer absolute ethyl alcohol, and absolute ethyl alcohol's solubility can be good, can quick dissolution coating layer powder, has prevented that coating layer powder from adsorbing in dust collecting equipment's inlet tube and exit tube.

As an improvement of the method for cleaning the lithium ion battery pole piece in the present invention, the step 4 of scrubbing the pole piece with the solvent specifically includes the following steps:

step 4.1) spraying a solvent to the welding groove on one surface of the pole piece, and scrubbing the welding groove sprayed with the solvent by using a wiping device;

step 4.2) after the scrubbing is finished, spraying a solvent on the welding groove on the other surface of the pole piece, and scrubbing the welding groove on the surface by using a scrubbing device;

and 4.3) detecting the scrubbing effect of the pole piece with two scrubbed surfaces through mechanical vision equipment.

As an improvement of the method for cleaning the lithium ion battery pole piece, step 4.1 is to perform die cutting on the edge powder of the welding groove before spraying the solvent on the pole piece. Through cold pressing, the powder adhesive force of the coating layer at the edge of the welding groove is enhanced, and then through die cutting, the powder remained at the edge of the welding groove after cold pressing can be removed, so that the cleaning effect is further improved.

As an improvement of the cleaning method of the lithium ion battery pole piece, the wiping device comprises a wiping head and dust-free paper, wherein the wiping head is used for wiping the welding groove, and the dust-free paper is used for cleaning the wiping head. The cleaning head is cleaned by using the dust-free paper, so that the cleaning effect is improved.

As an improvement of the cleaning method of the lithium ion battery pole piece, the wiping head is made of a mixed material of hard foam and soft foam. The mixed material of soft and hard foam can provide proper wear resistance and softness, greatly improve the wiping effect of the wiping head and prolong the service life.

As an improvement of the cleaning method of the lithium ion battery pole piece, powder of the coating layer falling off in the scrubbing process of the welding groove in the step 4.1 and the step 4.2 is adsorbed by vacuum adsorption equipment. The powder falling in the process of scrubbing the welding groove is adsorbed by the vacuum adsorption equipment, so that the cleanliness of the welding groove after scrubbing is effectively ensured, and the welding effect of the pole piece and the pole lug is improved.

As an improvement of the cleaning method of the lithium ion battery pole piece, the mechanical vision device is a CCD camera or a CMOS camera. The industrial-grade CCD camera is preferably selected, has the characteristics of high resolution, low noise, high sensitivity, wide dynamic range and the like, can effectively detect the gray values of the first welding groove and the second welding groove, and improves the detection precision and efficiency.

The invention has the beneficial effects that: compared with the prior art, the invention adopts a mode of laser cleaning and solvent scrubbing, and primarily cleans the pole piece by utilizing low-power laser before cold pressing, so that most coating layer powder at the welding groove is cleaned, the damage to the pole piece is effectively reduced, and the coating layer powder remained at the welding groove after cleaning is not stressed during subsequent cold pressing, so that the coating layer powder at the position has small cohesive force and is easy to scrub, therefore, the coating layer powder can be easily cleaned when the solvent scrubbing is carried out, the cleaning effect is obviously improved, and the problem that the size of the traditional groove position is difficult to control is avoided.

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 of the operation of the present invention;

FIG. 2 is a process capability example of weld pull in an 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.

In the present invention, unless otherwise expressly specified or limited, the terms "mounted," "connected," "secured," and the like are to be construed broadly and can, for example, be fixedly connected, detachably connected, or integrally connected; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meanings of the above terms in the present invention can be understood by those skilled in the art according to specific situations.

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

As shown in fig. 1, a method for cleaning a lithium ion battery pole piece includes the following steps:

step 1) placing a pole piece in a coating machine for coating, and primarily cleaning a welding groove on the coated pole piece by using low-power laser;

step 2) after the preliminary cleaning is finished, cold pressing the pole piece by passing through a roller to tightly compact the coating layer and the pole piece;

step 3) cutting the cold-pressed pole piece by using cutting equipment according to the size specification of the battery to obtain a small pole piece;

and 4) carrying out solvent scrubbing on the pole piece obtained in the step 3).

According to the scheme of the invention, a mode of laser cleaning and solvent scrubbing is adopted, compared with the traditional mode of only laser cleaning or solvent cleaning, the pole piece is cleaned primarily by using low-power laser before cold pressing, most of coating layer powder at the welding groove is cleaned, the damage to the pole piece is effectively reduced, and the coating layer powder remained at the welding groove after cleaning is not stressed during subsequent cold pressing, so that the coating layer powder at the position is low in cohesive force and easy to scrub, therefore, the coating layer powder can be easily cleaned during solvent scrubbing, the cleaning effect is obviously improved, and the problem that the size of the traditional groove position is difficult to control is solved.

Wherein the output power of the laser is 20-90 w. The pressure applied by cold pressing is 1-10000 kgf, and the rolling speed is 4-20 m/min. The solvent can be any one of N-methyl pyrrolidone, absolute ethyl alcohol, butanone, epoxy resin, diethyl carbonate, propylene carbonate, methyl ethyl carbonate, dimethyl carbonate and polypropylene.

Preferably, the solvent scrubbing of the pole piece in the step 4 specifically comprises the following steps:

step 4.1) spraying a solvent to the welding groove on one surface of the pole piece, and scrubbing the welding groove sprayed with the solvent by using a wiping device;

step 4.2) after the scrubbing is finished, spraying a solvent on the welding groove on the other surface of the pole piece, and scrubbing the welding groove on the surface by using a scrubbing device;

and 4.3) detecting the scrubbing effect of the pole piece with two scrubbed surfaces through mechanical vision equipment.

Preferably, step 4.1 further includes die cutting the edge powder of the welding groove before spraying the solvent on the pole piece. Through cold pressing, the powder adhesive force of the coating layer at the edge of the welding groove is enhanced, and then through die cutting, the powder remained at the edge of the welding groove after cold pressing can be removed, so that the cleaning effect is further improved.

Preferably, the wiping device comprises a wiping head for wiping the welding bath and a dust-free paper for cleaning the wiping head. In addition, in order to improve the wiping effect of the wiping head, the wiping head is made of a mixed material of hard foam and soft foam, so that proper wear resistance and flexibility are provided for the wiping process, and the service life is prolonged.

Preferably, powder of the coating layer falling off from the welding groove in the step 4.1 and the step 4.2 in the scrubbing process is adsorbed by a vacuum adsorption device. The powder falling in the process of scrubbing the welding groove is adsorbed by the vacuum adsorption equipment, so that the cleanliness of the welding groove after scrubbing is effectively ensured, and the welding effect of the pole piece and the pole lug is improved.

Preferably, the mechanical vision device is a CCD camera or a CMOS camera. The industrial-grade CCD camera is preferably selected, has the characteristics of high resolution, low noise, high sensitivity, wide dynamic range and the like, can effectively detect the gray values of the first welding groove and the second welding groove, and improves the detection precision and efficiency.

As shown in fig. 2, in order to detect the influence of the cleaning method of the present invention on the welding effect, in this embodiment, a process capability test is performed on the welding tension of the cleaned pole piece and the tab, wherein the number of the tested samples is 32, the abscissa is the welding tension, the unit is gram force, and the ordinate is the number of the extracted samples.

The foregoing description shows and describes several preferred embodiments of the invention, but as aforementioned, it is to be understood that the invention is not limited to the forms disclosed herein, but is not to be construed as excluding other embodiments and is capable of use in various other combinations, modifications, and environments and is capable of changes within the scope of the inventive concept as expressed herein, commensurate with the above teachings, or the skill or knowledge of the relevant art. And that modifications and variations may be effected by those skilled in the art without departing from the spirit and scope of the invention as defined by the appended claims.