Method and device for pole piece treatment in lithium ion battery failure quantitative analysis

Abstract

The invention discloses a method and a device for pole piece treatment through lithium ion battery failure quantitative analysis, and the method comprises the following steps: S1, disassembling a circulated lithium battery, taking out a pole piece, and removing impurities on the surface of the pole piece; s2, fixing the pole piece on a sample table, and dividing the surface of the pole piece into a powder scraping area and a reserving area; s3, the powder in the powder scraping area is scraped through a flexible scraper, and the scraped powder is collected in a negative pressure mode; s4, the collected powder is subjected to chemical analysis, and meanwhile, the pole piece with the powder scraped in the step S3 is made into a single-face pole piece; and S5, assembling the single-sided pole piece in the step S4 into a battery, and taking the single-sided pole piece as a working electrode. According to the invention, a lossless, accurate and repeatable pole piece processing method is provided for the research of the failure mechanism of the lithium ion battery, a solid theoretical foundation is laid for the diagnosis of the failure mechanism of the battery, and the product quality can be further improved by identifying the failure reason.

Description

Technical Field

[0001] This invention relates to the field of lithium battery testing technology, and in particular to a method and apparatus for quantitative analysis of lithium-ion battery failure and processing of electrode sheets. Background Technology

[0002] The performance failure mechanisms of lithium-ion batteries include loss of active lithium, damage to the structure of active materials, electrolyte decomposition, and dissolution of transition metals. Identifying the specific causes of failure requires disassembling the battery and further chemical analysis of the electrode sheets and positive and negative electrode materials. Therefore, disassembling and analyzing batteries after cycle testing is a crucial step. By comparing the changes in the physicochemical properties (such as morphology, crystal structure, and elemental composition) of the positive and negative electrode sheets before and after cycling, the degradation mechanism of lithium-ion batteries can be analyzed in depth. Currently, the most common analytical method is to scrape off the active material from the electrode sheets after cycling, reuse it as a working electrode, and assemble it with lithium sheets and electrolyte to form a coin cell for electrochemical testing. However, existing scraping and processing methods have serious drawbacks: the scraping process introduces contamination, the sample representativeness is insufficient, and the material damage prevents "non-destructive" extraction. Therefore, there is an urgent need in this field for a method that can perform targeted, micro-scale, and non-destructive scraping of the electrode sheets after cycling, while preserving the original material information to the maximum extent, in order to improve the accuracy and reliability of subsequent analytical data. Summary of the Invention

[0003] To address the technical problems existing in the background art, the present invention proposes a method and apparatus for quantitative analysis and processing of electrode sheets in lithium-ion batteries.

[0004] This invention proposes a method for quantitative analysis and treatment of electrode sheets in lithium-ion batteries, comprising the following steps:

[0005] S1. Disassemble the cycled lithium battery and remove the electrode plates, removing impurities from the surface of the electrode plates;

[0006] S2. Fix the electrode on the sample stage and divide the electrode surface into a powder scraping area and a retention area;

[0007] S3. The powder in the powder scraping area is scraped off by a flexible scraper and the scraped powder is collected by negative pressure.

[0008] S4. Perform chemical analysis on the collected powder, and at the same time, process the electrode sheet after scraping off the powder in step S3 into a single-sided electrode sheet.

[0009] S5. Assemble the single-sided electrode from step S4 into a battery and use the single-sided electrode as the working electrode.

[0010] As a further optimization of the present invention, the disassembly of the lithium battery in step S1 is carried out in an inert gas protected environment, thereby ensuring the safety of the operation.

[0011] As a further optimization of the present invention, in step S1, the electrode is gently rinsed with an organic solvent to remove impurities from the electrode, and then dried in a vacuum drying oven to remove the organic solvent.

[0012] The mild organic solvent can be a low-boiling-point solvent such as dimethyl carbonate or ethyl methyl carbonate, thus ensuring that impurities on the electrode surface can be removed gently.

[0013] As a further optimization of the present invention, the powder scraping area in step S2 is a region with cracks and discontinuity, and the retention area is a region without impurities and continuous without cracks.

[0014] This ensures the quality of the single-sided electrode manufactured in the reserved area, while the cracked powder scraping area facilitates the scraping of powder by a flexible scraper.

[0015] As a further optimization of the present invention, in step S2, the surface of the electrode is divided into sections using an optical microscope.

[0016] This ensures the accuracy of the partitioning.

[0017] As a further optimization of the present invention, the material of the flexible scraper in step S3 is polyetheretherketone.

[0018] The flexible scraper of this material is inert, high-strength, and does not easily produce debris, thus ensuring the accuracy of material extraction while scraping off electrode powder.

[0019] As a further optimization of the present invention, the speed at which the flexible scraper moves to scrape the powder in step S3 is 0.1-1.0 mm / s.

[0020] While ensuring efficient powder scraping, avoid damaging the electrode sheet and the flexible scraper.

[0021] As a further optimization of the present invention, in step S4: a single-sided electrode is prepared from the reserved area of ​​the electrode: the active material in the reserved area is adsorbed by negative pressure, and the reserved area of ​​the electrode is punched into a circular electrode for a coin cell.

[0022] The electrodes in the reserved area are cleaned and then made into circular electrodes to ensure the accuracy of the test.

[0023] As a further optimization of the present invention, in step S5: when installing the circular electrode, one side of the original electrode layer is kept facing the separator and the lithium metal sheet, and after adding an appropriate amount of electrolyte, it is encapsulated.

[0024] This ensures that the circular electrode is used as the working electrode, thus improving the accuracy of the detection.

[0025] An apparatus for quantitative analysis and processing of electrode sheets in lithium-ion battery failure includes a worktable with an electrode sheet fixing area. The electrode sheet is fixed in the electrode sheet by a negative pressure method. A mounting base is mounted on the worktable via a drive component. A flexible scraper and a negative pressure tube are mounted on the mounting base, with the opening of the negative pressure tube facing the working part of the flexible scraper.

[0026] The method and apparatus proposed in this invention for quantitative analysis of lithium-ion battery failures provide a non-destructive, precise, quantitative, and repeatable electrode processing method for the study of lithium-ion battery failure mechanisms. This lays a solid theoretical foundation for diagnosing battery failure mechanisms and can further improve product quality by identifying the causes of failure.

[0027] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may become apparent by practice of the invention. Attached Figure Description

[0028] Figure 1 This is a flowchart of the method of the present invention;

[0029] Figure 2 This is a schematic diagram of the workbench structure of the present invention;

[0030] Figure 3 This is a schematic diagram of the structure after the electrode sheet of the present invention is placed on the support block;

[0031] Figure 4 This is a cross-sectional view of the present invention;

[0032] In the diagram: 1. Workbench; 2. Negative pressure pipe; 3. Flexible scraper; 4. Robotic arm; 5. Support block; 50. Negative pressure through hole; 6. Negative pressure box; 7. Flattening block. Detailed Implementation

[0033] Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings, wherein the same or similar symbols denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0034] like Figure 1 The method shown here is for quantitative analysis and treatment of electrode sheets in lithium-ion batteries, and includes the following steps:

[0035] S1. Disassemble the cycled lithium battery and remove the electrode sheets, removing impurities from the surface of the electrode sheets, which include positive electrode sheets and negative electrode sheets.

[0036] To ensure safety, the disassembly of lithium batteries is carried out in an environment protected by inert gas.

[0037] The electrodes are gently rinsed with organic solvents to remove impurities, and then dried in a vacuum drying oven to remove the organic solvents.

[0038] The mild organic solvent can be a low-boiling-point solvent such as dimethyl carbonate or ethyl methyl carbonate, thus ensuring that impurities on the electrode surface can be removed gently.

[0039] S2. Fix the electrode on the sample stage and keep the electrode horizontal and flat. Observe the surface of the electrode through an optical microscope and divide the surface of the electrode into a powder scraping area and a retention area. After the division is completed, use an existing marker pen to draw lines to distinguish them.

[0040] The powder scraping zone is a cracked and discontinuous area, while the retention zone is a continuous and crack-free area free of impurities.

[0041] To ensure the quality of the single-sided electrode manufactured in the reserved area, the powder scraping area with cracks facilitates the scraping of material powder by the flexible scraper 3.

[0042] S3. The powder in the powder scraping area is scraped by the flexible scraper 3 and the scraped powder is collected by negative pressure.

[0043] The flexible scraper 3 is made of polyetheretherketone (PEEK), which is inert, has high strength, and is not prone to producing debris. This ensures the accuracy of the extracted substance while scraping off the electrode powder. The flexible scraper 3 moves at a speed of 0.1-1.0 mm / s to scrape off the powder.

[0044] Specifically, the existing robotic arm 4 can drive the scraper to move. The robotic arm 4 also has a negative pressure tube 2. When the flexible scraper 3 scrapes the powder, the scraped powder is adsorbed into the powder container by negative pressure. The powder container can be a bottle-shaped structure.

[0045] S4. Perform chemical analysis on the collected powder, and at the same time, process the electrode sheet after scraping off the powder in step S3 into a single-sided electrode sheet.

[0046] To prepare a single-sided electrode from the reserved area of ​​the electrode sheet: the active material in the reserved area is adsorbed by negative pressure, and the reserved area of ​​the electrode sheet is punched into a circular electrode sheet for a coin cell; the electrode sheet in the reserved area is cleaned and then made into a circular electrode sheet, thereby ensuring the accuracy of the test.

[0047] S5. Assemble the single-sided electrode from step S4 into a battery and use the single-sided electrode as the working electrode; when installing the circular electrode, keep one side of the original electrode layer facing the separator and the lithium metal sheet, add an appropriate amount of electrolyte and then encapsulate it, thereby ensuring that the circular electrode is used as the working electrode and increasing the accuracy of detection.

[0048] The beneficial effect of this method is the integrity of the sampling area. It enables simultaneous analysis of the intrinsic physicochemical properties of the active material and the electrochemical properties of the electrode material on the same electrode sample, providing a comprehensive understanding of the overall state of the failed electrode.

[0049] Quantitative testing of samples: Simultaneous vacuum collection and precise weighing through scraping provide a reliable basis for quantitative chemical analysis of powder samples; by preserving the original interface, electrochemical quantitative data that truly reflects the electrode state are obtained.

[0050] Accuracy of analytical data: The flexible scraper 3 and synchronous collection technology can avoid impurity contamination and ensure the authenticity and reliability of subsequent analytical results;

[0051] Repeatable standardized process: It provides a standardized and repeatable operating process, which greatly reduces the error introduced by human operation and is suitable for cause diagnosis in battery research and development, quality control and failure analysis;

[0052] like Figure 2 - Figure 4 The apparatus shown is for quantitative analysis and processing of electrode sheets for lithium-ion battery failure. It includes a worktable 1 with an electrode sheet fixing area. The electrode sheet is fixed in the electrode sheet fixing area by negative pressure. A support block 5 is detachably installed on the worktable 1. The electrode sheet is placed on the support block 5. The support block 5 has multiple negative pressure through holes 50. The negative pressure through holes 50 are connected to external negative pressure equipment to achieve adsorption and fixation of the electrode sheet.

[0053] Preferably, to ensure that the electrode sheet is placed flat on the support block 5, when negative pressure is introduced into the negative pressure through hole 50, a flattening block 7 (such as...) is placed on the electrode sheet. Figure 3 As shown), the flattening block 7 can be a block-shaped component with a flat bottom and relatively large mass in the prior art. Then, a negative pressure adsorption electrode is introduced into the negative pressure through hole 50 to ensure that the electrode is in a flat state. Then, the flattening block 7 is taken out for subsequent scraping operations.

[0054] Preferably, in order to ensure that the pressure inside each negative pressure through hole 50 is equal, the bottom of the workbench 1 is provided with a negative pressure box 6, the negative pressure box 6 has a dispersion cavity, and the workbench 1 has a connecting hole that communicates with the dispersion cavity. When the support block 5 is installed on the workbench 1, the connecting hole communicates with the negative pressure through hole 50.

[0055] Preferably, the workbench 1 has a rubber connector, and the support block 5 has a connecting hole that communicates with the negative pressure through hole 50. When the support block 5 is fixed on the workbench 1, the rubber connector extends into the connecting hole and is in a compressed state, thereby realizing the communication between the dispersion chamber and the negative pressure through hole 50. In order to ensure stability, the bottom of the support block 5 is in contact with the top surface of the workbench 1. Preferably, it can be determined whether the support block 5 is parallel to the bottom by placing a level on the support block 5.

[0056] Preferably, the connecting hole includes a first connecting part and a second connecting part that are connected. The axes of the first connecting part and the second connecting part are parallel, thereby ensuring the pressure balance within the negative pressure through hole 50, thereby ensuring the stability of the electrode fixing, and thus increasing the detection accuracy.

[0057] Specifically, the electrode fixing area is provided with a worktable 1 on which a mounting base is mounted via a drive component. This drive component can be a robotic arm 4 in the prior art. The figure is only a schematic diagram. For the specific robotic arm 4, please refer to the existing structure. The drive component is used to drive the mounting base to move horizontally or vertically. A flexible scraper 3 and a negative pressure tube 2 are mounted on the mounting base. The opening of the negative pressure tube 2 is directly opposite the working part of the flexible scraper 3. The negative pressure tube 2 adsorbs the powder scraped off by the scraper through negative pressure. The drive component drives the scraper and the negative pressure tube 2 to move synchronously, thereby ensuring the effect of the powder adsorbed by the negative pressure tube 2.

[0058] It should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the present invention.

[0059] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection, an electrical connection, or a connection that allows communication between the components; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0060] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "over," and "on top" of the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature.

[0061] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A method for quantitative analysis and processing of electrode sheets in lithium-ion battery failure, characterized in that, Includes the following steps: S1. Disassemble the cycled lithium battery and remove the electrode plates, removing impurities from the surface of the electrode plates; S2. Fix the electrode on the sample stage and divide the electrode surface into a powder scraping area and a retention area; S3. The powder in the powder scraping area is scraped by a flexible scraper and the scraped powder is collected by negative pressure. S4. Perform chemical analysis on the collected powder, and at the same time, process the electrode sheet after scraping off the powder in step S3 into a single-sided electrode sheet. S5. Assemble the single-sided electrode from step S4 into a battery and use the single-sided electrode as the working electrode.

2. The method for quantitative analysis and processing of electrode sheets for lithium-ion battery failure according to claim 1, characterized in that, The disassembly of the lithium battery in step S1 is carried out in an inert gas protected environment.

3. The method for quantitative analysis and processing of electrode sheets for lithium-ion battery failure according to claim 1, characterized in that, In step S1, the electrode is gently rinsed with an organic solvent to remove impurities, and then dried in a vacuum drying oven to remove the organic solvent.

4. The method for quantitative analysis and processing of electrode sheets for lithium-ion battery failure according to claim 1, characterized in that, The powder scraping area in step S2 is a cracked and discontinuous area, while the retention area is a continuous and crack-free area free of impurities.

5. The method for quantitative analysis and processing of electrode sheets for lithium-ion battery failure according to claim 1, characterized in that, In step S2, the surface of the electrode is divided into sections using an optical microscope.

6. The method for quantitative analysis and processing of electrode sheets for lithium-ion battery failure according to claim 1, characterized in that, The flexible scraper in step S3 is made of polyetheretherketone.

7. The method for quantitative analysis and processing of electrode sheets for lithium-ion battery failure according to claim 1, characterized in that, In step S3, the flexible scraper moves at a speed of 0.1-1.0 mm / s to scrape the powder.

8. The method for quantitative analysis and processing of electrode sheets for lithium-ion battery failure according to claim 1, characterized in that, In step S4: Prepare a single-sided electrode from the reserved area of ​​the electrode: Adsorb the active material in the reserved area by negative pressure, and punch the reserved area of ​​the electrode into a circular electrode for a coin cell.

9. The method for quantitative analysis and processing of electrode sheets for lithium-ion battery failure according to claim 1, characterized in that, In step S5: When installing the circular electrode, keep one side of the original electrode layer facing the separator and the lithium metal sheet, add an appropriate amount of electrolyte, and then encapsulate.

10. The apparatus for quantitative analysis and processing of electrode sheets in lithium-ion batteries according to claim 1, characterized in that, The device includes a worktable with an electrode fixing area, where the electrode is fixed by negative pressure. A mounting base is mounted on the worktable via a drive component, and a flexible scraper and a negative pressure tube are mounted on the mounting base. The opening of the negative pressure tube faces the working part of the flexible scraper.

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