Slurry recovery method

Abstract

The present application provides a slurry recovery method, and belongs to the technical field of battery manufacturing. The slurry recovery method comprises: measuring the viscosity of an electrode slurry utilized during an electrode coating process; and in response to the viscosity of the electrode slurry being not greater than a viscosity threshold value, performing slurry preparation on the electrode slurry according to a first slurry preparation process to obtain a slurry that can be used again, or in response to the viscosity of the electrode slurry being greater than the viscosity threshold value, performing slurry preparation on the electrode slurry according to a second slurry preparation process to obtain a slurry that can be used again, the second slurry preparation process being different from the first slurry preparation process.

Description

Slurry recovery method

[0001] Cross-references

[0002] This application refers to Chinese Patent Application No. 202410361467.2, filed on March 27, 2024, entitled “Slurry Recovery Method”, which is incorporated herein by reference in its entirety. Technical Field

[0003] The present application relates to the field of battery manufacturing technology, and in particular to a slurry recovery method. Background Art

[0004] Energy conservation and emission reduction are key to the sustainable development of the automotive industry. Electric vehicles, due to their energy-saving and environmentally friendly advantages, have become an important component of the sustainable development of the automotive industry. For electric vehicles, battery technology is a key factor in their development.

[0005] Electrode coating is a critical step in battery production, and the quality of this coating is crucial to battery quality. The electrode slurry used in this process is a homogeneous mixture of active materials, conductive agents, binders, and solvents. The quality of the electrode slurry directly impacts battery performance and stability. During the electrode coating process, the electrode slurry physically gels after a period of time within the trough, resulting in wrinkles during coating. This often requires replacement of the electrode slurry, and the existing slurry is discarded.

[0006] Summary of the Invention

[0007] The present application aims to solve at least one of the technical problems existing in the background art. To this end, one object of the present application is to provide a slurry recovery method to alleviate, mitigate or eliminate the problems in the related art.

[0008] An embodiment of the first aspect of the present application provides a slurry recovery method, comprising: detecting the viscosity of the electrode slurry used in the electrode coating process; in response to the viscosity of the electrode slurry being not greater than a viscosity threshold, slurrying the electrode slurry according to a first slurrying process to obtain a reusable slurry; or in response to the viscosity of the electrode slurry being greater than a viscosity threshold, slurrying the electrode slurry according to a second slurrying process to obtain a reusable slurry, wherein the second slurrying process is different from the first slurrying process.

[0009] In the technical solution of the embodiment of the present application, different pulping processes are used to process the recovered battery slurry according to the viscosity of the electrode slurry, so that the recycled electrode slurries of different viscosities can meet the viscosity requirements for reuse after treatment, thereby realizing the recycling and reuse of the electrode slurry, reducing the scrapping of the electrode slurry, and improving the utilization rate.

[0010] In some embodiments, the first slurrying process includes circulating a coarse mixed slurry prepared from a powder and a solvent, a binder, and an electrode slurry between a first circulation tank and a second circulation tank via a first pipe for a first period of time, wherein the first pipe connects the first circulation tank and the second circulation tank, and a disperser including an impeller is disposed in the first pipe, and the impeller rotates at a first speed. When the viscosity of the recovered electrode slurry is low, the recovered electrode slurry, the coarse mixed slurry, and the binder are circulated through the two circulation tanks and the disperser, so that the viscosity of the reusable slurry obtained after the circulation meets the use requirements and can be reused, thereby improving the utilization rate of the electrode slurry.

[0011] In some embodiments, circulating the coarse mixed slurry, binder, and electrode slurry prepared from the powder and solvent between a first circulation tank and a second circulation tank via a first conduit includes rotating the first circulation tank at a second rotational speed and the second circulation tank at a third rotational speed, wherein the second and third rotational speeds are less than the first rotational speed. During the circulation process, while the disperser is being used for dispersion, the two circulation tanks are also rotated, thereby achieving more uniform dispersion and mixing of the coarse mixed slurry, binder, and electrode slurry, thereby improving the dispersion effect.

[0012] In some embodiments, the powder includes a first raw material and a second raw material, and the first slurrying process further includes the following steps to prepare a coarse mixed slurry: dry mixing the first raw material and the second raw material in a premixing tank to obtain a premix; mixing the premix with a solvent to obtain a premixed slurry; and circulating the premixed slurry between a first circulation tank and a second circulation tank via a first pipe for a second time period to obtain a coarse mixed slurry, wherein the impeller rotates at a fourth speed, the fourth speed being greater than the first speed, and the second time period being greater than the first time period. After the two powders are premixed, they are mixed with the solvent and circulated using two circulation tanks and a disperser, so that the dispersion and mixing of the coarse mixed slurry are more uniform, thereby improving the quality of the coarse mixed slurry.

[0013] In some embodiments, the disperser is further connected to a premixing tank via a second pipe, and mixing the premix with the solvent to obtain a premixed slurry includes: adding a solvent to a first circulation tank; transferring the solvent from the first circulation tank to the disperser via a first pipe, and transferring the premix from the premixing tank to the disperser via a second pipe, wherein the impeller rotates at a fifth speed to mix the premix with the solvent, the fifth speed being greater than the first speed; transferring the mixture of the premix and the solvent from the disperser to the first circulation tank via the first pipe; and circulating the mixture of the premix and the solvent between the first circulation tank and the disperser for a third time period to obtain the premixed slurry, wherein the impeller rotates at the fifth speed, and the third time period is greater than the first time period. After obtaining the premix, the premix and the solvent are dispersed and mixed by the disperser, so that the dispersion and mixing of the premixed slurry is more uniform, thereby improving the quality of the premixed slurry.

[0014] In some embodiments, circulating the mixture of the premix and the solvent between the first circulation tank and the disperser includes rotating the first circulation tank at a sixth speed, the sixth speed being less than the first speed. During the circulation process, while the disperser is being used for dispersion, the first circulation tank is also rotated, thereby achieving more uniform dispersion and mixing of the premix and the solvent, thereby improving the dispersion effect.

[0015] In some embodiments, the second slurrying process includes circulating the electrode slurry between a first circulation tank and a second circulation tank via a first pipe for a fourth time period, wherein the first pipe connects the first circulation tank and the second circulation tank, and a disperser including an impeller is disposed in the first pipe, and the impeller rotates at a seventh speed. When the viscosity of the recovered electrode slurry is relatively high, the recovered electrode slurry is separately circulated using two circulation tanks and dispersers, so that the viscosity of the reusable slurry obtained after the circulation meets the use requirements and can be reused, thereby improving the utilization rate of the electrode slurry and simplifying the operation process.

[0016] In some embodiments, circulating the electrode slurry between the first circulation tank and the second circulation tank via the first conduit includes rotating the first circulation tank at an eighth speed and rotating the second circulation tank at a ninth speed, wherein the eighth and ninth speeds are less than the seventh speed. During the circulation process, while the disperser is being used for dispersion, the two circulation tanks are also rotated, so that the recovered electrode slurry is dispersed and mixed more evenly, thereby improving the dispersion effect.

[0017] In some embodiments, the slurry recovery method further includes: detecting the viscosity of the reusable slurry; and in response to the viscosity of the reusable slurry being within a predetermined viscosity range, adding the reusable slurry to a transfer tank for reuse in the electrode coating process. After processing the recovered electrode slurry, the viscosity of the reusable slurry is detected. If the viscosity meets the usage requirements, the reusable slurry can be reused, thereby reducing the waste of the electrode slurry and improving its utilization rate.

[0018] In some embodiments, the electrode coating process includes a gravure printing process, and the electrode slurry includes anode slurry. Recycling the anode slurry in the gravure printing process can achieve reuse of the slurry and reduce anode slurry waste in the electrode coating process.

[0019] In some embodiments, the anode slurry includes sodium carboxymethyl cellulose, styrene-butadiene emulsion, conductive carbon powder, and deionized water, and has a viscosity threshold of greater than or equal to 40 mPa·s and less than or equal to 60 mPa·s. Selecting an appropriate viscosity threshold based on the materials included in the anode slurry and treating the recovered anode slurry accordingly can improve the quality of the resulting reusable slurry.

[0020] The above description is only an overview of the technical solution of the present application. In order to more clearly understand the technical means of the present application, it can be implemented in accordance with the contents of the specification. In order to make the above and other purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are listed below. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following is a brief introduction to the drawings required for use in the embodiments of the present application. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on the drawings without creative work.

[0022] In the accompanying drawings, unless otherwise specified, the same reference numerals throughout the multiple drawings represent the same or similar components or elements. These drawings are not necessarily drawn to scale. It should be understood that these drawings only depict some embodiments disclosed in this application and should not be construed as limiting the scope of this application.

[0023] FIG1 is a connection diagram of a slurry recovery system according to some embodiments of the present application;

[0024] FIG2 is a schematic flow diagram of a slurry recovery method according to some embodiments of the present application;

[0025] FIG3 is a schematic diagram of a process for preparing a coarse mixed slurry according to some embodiments of the present application;

[0026] FIG4 is a schematic diagram of a process for obtaining a premixed slurry in some embodiments of the present application;

[0027] FIG5 is a schematic diagram of a process for slurry recycling according to some embodiments of the present application;

[0028] FIG6 is a schematic flow diagram of a slurry recovery method according to some embodiments of the present application.

[0029] Explanation of the reference numerals: slurry recovery system 10 ; first raw material metering tank 11 , second raw material metering tank 12 , sending tank 13 , premixing tank 14 , disperser 15 , first circulation tank 16 , second circulation tank 17 , first pipeline 18 , second pipeline 19 . DETAILED DESCRIPTION

[0030] The following embodiments of the technical solution of the present application will be described in detail with reference to the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present application and are therefore only examples and are not intended to limit the scope of protection of the present application.

[0031] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which this application belongs; the terms used herein are only for the purpose of describing specific embodiments and are not intended to limit this application; the terms "including" and "having" and any variations thereof in the specification and claims of this application and the above-mentioned figure descriptions are intended to cover non-exclusive inclusions.

[0032] In the description of the embodiments of this application, the technical terms "first" and "second" are used only to distinguish different objects and should not be understood to indicate or imply relative importance or implicitly specify the quantity, specific order, or primary and secondary relationship of the indicated technical features. In the description of the embodiments of this application, the meaning of "plurality" is more than two, unless otherwise clearly and specifically defined.

[0033] References herein to "embodiments" mean that a particular feature, structure, or characteristic described in connection with the embodiments may be included in at least one embodiment of the present application. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor does it constitute an independent or alternative embodiment that is mutually exclusive of other embodiments. It is understood, both explicitly and implicitly, by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0034] In the description of the embodiments of this application, the term "and / or" is simply a description of the association relationship between associated objects, indicating that three relationships can exist. For example, A and / or B can represent the following three situations: A exists alone, A and B exist simultaneously, and B exists alone. In addition, the character " / " in this document generally indicates that the associated objects are in an "or" relationship.

[0035] In the description of the embodiments of the present application, the term "multiple" refers to more than two (including two). Similarly, "multiple groups" refers to more than two groups (including two groups), and "multiple pieces" refers to more than two pieces (including two pieces).

[0036] In the description of the embodiments of the present application, the technical terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing the embodiments of the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the embodiments of the present application.

[0037] In the description of the embodiments of the present application, unless otherwise expressly specified or limited, technical terms such as "installed," "connected," "connected," and "fixed" should be understood in a broad sense. For example, they can refer to fixed connections, detachable connections, or integration; mechanical connections or electrical connections; direct connections or indirect connections through an intermediate medium; internal connections between two components or interactions between two components. Those skilled in the art can understand the specific meanings of the above terms in the embodiments of the present application based on specific circumstances.

[0038] Currently, market developments indicate that power batteries are becoming increasingly widely used. They are not only used in energy storage systems such as hydropower, thermal, wind, and solar power plants, but are also widely used in electric vehicles like electric bicycles, electric motorcycles, and electric vehicles, as well as in military equipment and aerospace. As power battery applications continue to expand, market demand is also growing.

[0039] Electrode coating is a critical step in battery production, and the quality of this coating is crucial to battery quality. The electrode slurry used in this process is a uniform mixture of active materials, conductive agents, binders, and solvents. The quality of the electrode slurry directly impacts battery performance and stability. The viscosity of the electrode slurry is a crucial parameter, determining its fluidity, coating uniformity, and drying efficiency.

[0040] Gravure coating is a common coating process in electrode coating. It offers advantages such as precise metering, simple operation, smooth coating surfaces, and high coating speeds. The working principle of gravure coating is that the coating is applied to the engraved points or lines of the gravure drum through rotation, and then the coating on the gravure drum is transferred to the coated material.

[0041] During the gravure coating process, the electrode slurry will physically gel after a period of time in the trough, resulting in wrinkles during coating. This often requires replacement of the electrode slurry, and the existing slurry is discarded. To reduce the amount of electrode slurry discarded during the gravure coating process, the electrode slurry can be recycled to obtain reusable slurry for reuse.

[0042] Based on the above considerations, a slurry recovery method was designed. By selecting different pulping processes according to the viscosity of the electrode slurry, reusable slurry was obtained, so that the recovered electrode slurry can be used again in the gravure coating process, reducing the scrap of electrode slurry and improving the utilization rate of electrode slurry.

[0043] The slurry recovery method disclosed in the embodiments of this application can be used, but is not limited to, in the production process of batteries used in electrical devices such as vehicles, ships, or aircraft. The slurry recovery method disclosed in this application can be used to recycle electrode slurry used in electrode coating processes, thereby reducing electrode slurry waste and improving electrode slurry utilization.

[0044] For the convenience of description, the following embodiments are described by taking a slurry recovery system 10 according to an embodiment of the present application as an example.

[0045] Referring to Figure 1, the slurry recovery system 10 includes a first raw material metering tank 11, a second raw material metering tank 12, a sending tank 13, a premixing tank 14, a disperser 15, a first circulation tank 16, and a second circulation tank 17. The first circulation tank 16 and the second circulation tank 17 are connected by a first pipe 18. The disperser 15 is disposed in the first pipe 18 and is also connected to the premixing tank 14 via a second pipe 19. The disperser 15 includes an impeller (not shown). When the impeller rotates, the solid and / or liquid materials flowing through the disperser 15 can be dispersed and mixed.

[0046] The embodiment of the present application provides a slurry recovery method 200. Referring to FIG2 , the slurry recovery method 200 includes steps 210-230:

[0047] Step 210 : detecting the viscosity of the electrode slurry used in the electrode coating process.

[0048] Step 220 : In response to the viscosity of the electrode slurry being not greater than the viscosity threshold, the electrode slurry is slurried according to a first slurrying process to obtain a reusable slurry.

[0049] Step 230 : In response to the viscosity of the electrode slurry being greater than a viscosity threshold, the electrode slurry is slurried according to a second slurrying process to obtain a reusable slurry.

[0050] The second pulping process is different from the first pulping process.

[0051] The electrode slurry used in the electrode coating process, especially the gravure coating process, must meet certain viscosity requirements to ensure coating quality. As the coating process continues, the electrode slurry in the trough tray will undergo physical gelation, resulting in changes in viscosity. When the electrode slurry needs to be recycled, step 210 can be performed to test the viscosity of the electrode slurry. Step 210 can be performed manually using a corresponding detection method or using an automated testing method, which is not limited in this disclosure.

[0052] For electrode slurries with different viscosities, different slurrying processes can be adopted to slurry them to obtain reusable slurries. The viscosity thresholds for different slurrying processes can be predetermined based on parameters such as the type, material, and ratio of the slurry. After the viscosity of the electrode slurry is detected, the slurrying process to be used for it is determined based on the relationship between the viscosity and the viscosity threshold. In step 220, when the viscosity of the electrode slurry is not greater than the viscosity threshold, it is slurried according to the first slurrying process to obtain a reusable slurry. In step 230, when the viscosity of the electrode slurry is greater than the viscosity threshold, it is slurried according to the second slurrying process to obtain a reusable slurry.

[0053] The first slurrying process and the second slurrying process can be determined according to factors such as the type of electrode slurry, the viscosity range, and a predetermined viscosity threshold.

[0054] According to the viscosity of the electrode slurry, different pulping processes are used to process the recycled battery slurry, so that the recycled electrode slurries of different viscosities can meet the viscosity requirements for reuse after treatment, realizing the recycling and reuse of the electrode slurry, reducing the scrap of the electrode slurry and improving the utilization rate.

[0055] According to some embodiments of the present application, the first pulping process includes:

[0056] The coarse mixed slurry prepared from the powder and the solvent, the binder and the electrode slurry are circulated between the first circulation tank 16 and the second circulation tank 17 via the first pipe 18 for a first period of time.

[0057] The first pipe 18 connects the first circulation tank 16 and the second circulation tank 17. A disperser 15 including an impeller is provided in the first pipe 18. The impeller rotates at a first speed.

[0058] In step 220, the viscosity of the electrode slurry is no greater than the viscosity threshold, indicating a relatively low viscosity. Therefore, in addition to the electrode slurry, a coarse mixed slurry and a binder are added during the first slurrying process to ensure that the viscosity of the resulting reusable slurry meets the required viscosity. In some embodiments, the materials, ratios, and other parameters of the coarse mixed slurry and binder added in step 220 are the same as those used in the electrode slurry preparation process. In this example, the binder can be styrene-butadiene latex (GAS).

[0059] In order to achieve a better dispersion and mixing effect, the coarse mixed slurry, binder and electrode slurry are circulated between the two circulation tanks. These materials need to flow through the first pipe 18 when entering the second circulation tank 17 from the first circulation tank 16 or when entering the first circulation tank 16 from the second circulation tank 17. A disperser 15 is provided in the first pipe 18. The impeller of the disperser 15 rotates at a first speed. The first speed can be set according to the applicable occasion, and the present disclosure does not limit this. In the example, the first speed can be set to 1500 revolutions per minute (rpm).

[0060] Whenever the coarse mixed slurry, the binder and the electrode slurry pass through the disperser 15 , they are dispersed and mixed by the disperser 15 , thereby achieving a better dispersion effect.

[0061] The first duration of the circulation of the coarse mixed slurry, binder, and electrode slurry between the two circulation tanks can be set according to the applicable application, and this disclosure is not limited to this. In this example, the first duration can be set to 15 minutes. It should be understood that the first duration can also be reflected in the number of cycles.

[0062] When the viscosity of the recovered electrode slurry is low, the recovered electrode slurry, coarse mixed slurry and binder are circulated using two circulation tanks and a disperser, so that the viscosity of the reusable slurry obtained after the circulation meets the use requirements and can be used again, thereby improving the utilization rate of the electrode slurry.

[0063] According to some embodiments of the present application, circulating the coarse mixed slurry prepared from the powder and the solvent, the binder, and the electrode slurry between the first circulation tank 16 and the second circulation tank 17 via the first pipe 18 includes:

[0064] The first circulation tank 16 is rotated at a second rotational speed, and the second circulation tank 17 is rotated at a third rotational speed. The second rotational speed and the third rotational speed are lower than the first rotational speed.

[0065] When the coarse mixed slurry, binder, and electrode slurry circulate between the first circulation tank 16 and the second circulation tank 17, in order to achieve a better dispersion effect, the first circulation tank 16 and the second circulation tank 17 can also be in a rotating state. In some embodiments, the rotational speeds of the two circulation tanks can be the same or different from each other, and can be set to be less than the rotational speed of the impeller of the disperser 15 at this time (i.e., the first rotational speed). In the example, the first circulation tank 16 and the second circulation tank 17 rotate at the same speed, and the second rotational speed and the third rotational speed are both set to 30 revolutions per minute (rpm).

[0066] The present disclosure does not limit the rotation directions of the impeller, the first circulation tank 16 and the second circulation tank 17 .

[0067] During the circulation process, while the disperser is used for dispersion, the two circulation tanks are also rotated, so that the dispersion and mixing of the coarse mixed slurry, binder and electrode slurry can be more uniform, thereby improving the dispersion effect.

[0068] According to some embodiments of the present application, the powder includes a first raw material and a second raw material. The first pulping process further includes a process 300 to prepare a coarse mixed slurry. Referring to FIG. 3 , the process 300 includes steps 310-330:

[0069] Step 310 : dry-mix the first raw material and the second raw material in the premixing tank 14 to obtain a premix.

[0070] In step 320 , the premixture is mixed with a solvent to obtain a premixed slurry.

[0071] Step 330: Circulate the premixed slurry between the first circulation tank 16 and the second circulation tank 17 via the first pipe 18 for a second duration to obtain a coarse mixed slurry. The impeller rotates at a fourth speed, which is greater than the first speed. The second duration is greater than the first duration.

[0072] As shown in Figure 1, the first raw material is added to the first raw material metering tank 11, and the second raw material is added to the second raw material metering tank 12. The two powders are transferred to the premixing tank 14 via the sending tank 13. In the premixing tank 14, the first and second raw materials are mixed to form a premix. The first and second raw materials are solid raw materials used in the electrode slurry preparation process. In this example, the first raw material can be sodium carboxymethyl cellulose (CMC), and the second raw material can be conductive carbon powder (GCC).

[0073] The premix is ​​mixed with a solvent to obtain a premix slurry. In an example, the solvent may be deionized water (GSW).

[0074] After the premixed slurry is obtained, the premixed slurry is circulated between the first circulation tank 16 and the second circulation tank 17. In each cycle, the premixed slurry flows through the disperser 15 in the first pipeline 18. The impeller of the disperser 15 rotates at a fourth speed to disperse and mix the premixed slurry to achieve a better dispersion effect. In some embodiments, the fourth speed can be set to be greater than the first speed. In an example, the fourth speed can be set to 2250 revolutions per minute (rpm).

[0075] The second duration of the premixed slurry circulating between the two circulation tanks can be set according to the applicable application, and this disclosure does not limit this. In this example, the second duration can be set to 60 minutes. It should be understood that the second duration can also be reflected in the number of cycles.

[0076] The two powders are premixed and then mixed with a solvent, and circulated using two circulation tanks and a disperser, so that the dispersion and mixing of the coarse mixed slurry is more uniform, thereby improving the quality of the coarse mixed slurry.

[0077] According to some embodiments of the present application, the disperser 15 is further connected to the premixing tank 14 via a second pipe 19. Referring to FIG. 4 , step 320 includes steps 410-440:

[0078] In step 410 , a solvent is added to the first circulation tank 16 .

[0079] In step 420, the solvent is transferred from the first circulation tank 16 to the disperser 15 via the first pipe 18, and the premix is ​​transferred from the premix tank 14 to the disperser 15 via the second pipe 19. The impeller rotates at a fifth speed to mix the premix with the solvent. The fifth speed is greater than the first speed.

[0080] In step 430 , the mixture of the premix and the solvent is transferred from the disperser 15 to the first circulation tank 16 via the first pipeline 18 .

[0081] Step 440: Circulate the mixture of the premix and the solvent between the first circulation tank 16 and the disperser 15 for a third time period to obtain a premixed slurry. The impeller rotates at a fifth speed. The third time period is greater than the first time period.

[0082] As shown in Figure 1, a solvent may be added to the first circulation tank 16 and transferred to the disperser 15. The premix obtained in step 310 is also transferred from the premixing tank 14 to the disperser 15. The impeller of the disperser 15 rotates at a fifth speed to disperse and mix the premix and the solvent.

[0083] For the mixture of the premixture and the solvent after disperser 15 dispersion mixing in step 420, it can be transferred to the first circulation tank 16. In step 440, the mixture circulates between the first circulation tank 16 and the disperser 15 to achieve better dispersion mixing effect. In steps 420 and 440, the impeller of disperser 15 can be set to rotate at a fifth speed. In certain embodiments, the fifth speed can be set to be greater than the first speed. In an example, the fifth speed can be set to 2250 revolutions per minute (rpm).

[0084] It should be understood that steps 420, 430 and 440 can be performed asynchronously or synchronously, that is, all the solvents in the first circulation tank 16 and all the premixes in the premixing tank 14 can be transferred to the disperser 15 for dispersion and mixing, and the resulting mixture can be transferred to the first circulation tank 16, so that the mixture circulates between the first circulation tank 16 and the disperser 15; the solvent in the first circulation tank 16 and the premix in the premixing tank 14 can also be gradually transferred to the disperser 15 for dispersion and mixing, and the resulting mixture can be transferred to the first circulation tank 16. At this time, the original solvent may still be stored in the first circulation tank 16. During the process of the mixture circulating between the first circulation tank 16 and the disperser 15 in step 440, step 420 may also be performed at the same time, and the premix in the premixing tank 14 and the solvent in the first circulation tank 16 may still be gradually transferred to the disperser 15 and dispersed and circulated together with the mixture of the premix and the solvent.

[0085] The third duration during which the mixture of the premix and the solvent circulates between the first circulation tank 16 and the disperser 15 can be set according to the applicable application, and this disclosure does not limit this. In this example, the third duration can be set to 70 minutes. It should be understood that the third duration can also be reflected in the number of cycles.

[0086] After the premix is ​​obtained, the premix and the solvent are dispersed and mixed by a disperser, so that the dispersion and mixing of the premix slurry is more uniform, thereby improving the quality of the premix slurry.

[0087] According to some embodiments of the present application, circulating the mixture of the premix and the solvent between the first circulation tank 16 and the disperser 15 includes:

[0088] The first circulation tank 16 is rotated at a sixth rotational speed which is lower than the first rotational speed.

[0089] When the mixture of the premix and the solvent circulates between the first circulation tank 16 and the disperser 15, the first circulation tank 16 can also be rotated to achieve a better dispersion effect. In some embodiments, the rotation speed of the first circulation tank 16 can be set to a sixth rotation speed that is less than the first rotation speed. In an example, the sixth rotation speed can be set to 30 revolutions per minute (rpm).

[0090] The present disclosure does not limit the rotation directions of the impeller and the first circulation tank 16 .

[0091] During the circulation process, while the disperser is used for dispersion, the first circulation tank is also rotated, so that the dispersion and mixing of the premixture and the solvent can be more uniform, thereby improving the dispersion effect.

[0092] According to some embodiments of the present application, the second pulping process includes:

[0093] The electrode slurry is circulated between the first circulation tank 16 and the second circulation tank 17 via the first pipe 18 for a fourth period of time.

[0094] The first pipe 18 connects the first circulation tank 16 and the second circulation tank 17. A disperser 15 including an impeller is provided in the first pipe 18. The impeller rotates at a seventh speed.

[0095] In the second slurrying process, the viscosity of the electrode slurry is greater than the viscosity threshold. At this time, the viscosity of the electrode slurry is relatively high, so the viscosity of the obtained reusable slurry can be made to meet the use requirements by treating the electrode slurry alone.

[0096] In order to achieve a better dispersion and mixing effect, the electrode slurry is circulated between the two circulation tanks. The electrode slurry needs to flow through the first pipe 18 when entering the second circulation tank 17 from the first circulation tank 16 or when entering the first circulation tank 16 from the second circulation tank 17. A disperser 15 is provided in the first pipe 18. The impeller of the disperser 15 rotates at a seventh speed. The seventh speed can be set according to the applicable occasion, and the present disclosure does not limit this. In the example, the seventh speed can be set to 1500 revolutions per minute (rpm).

[0097] Whenever the electrode slurry passes through the disperser 15 , it is dispersed and mixed by the disperser 15 , thereby achieving a better dispersion effect.

[0098] The fourth duration of the electrode slurry circulating between the two circulation tubes can be set according to the applicable application, and this disclosure does not limit this. In the example, the fourth duration can be set to 15 minutes. It should be understood that the fourth duration can also be reflected in the number of cycles.

[0099] When the viscosity of the recovered electrode slurry is high, two circulation tanks and dispersers are used to circulate the recovered electrode slurry separately, so that the viscosity of the reusable slurry obtained after circulation meets the use requirements and can be used again, thereby improving the utilization rate of the electrode slurry and simplifying the operation process.

[0100] According to some embodiments of the present application, circulating the electrode slurry between the first circulation tank 16 and the second circulation tank 17 via the first pipe 18 includes:

[0101] The first circulation tank 16 is rotated at an eighth rotational speed, and the second circulation tank 17 is rotated at a ninth rotational speed. The eighth and ninth rotational speeds are lower than the seventh rotational speed.

[0102] When the electrode slurry circulates between the first circulation tank 16 and the second circulation tank 17, in order to achieve a better dispersion effect, the first circulation tank 16 and the second circulation tank 17 can also be rotated. In some embodiments, the rotational speeds of the two circulation tanks can be the same or different, and can be set to be lower than the current rotational speed of the impeller of the disperser 15 (i.e., the seventh rotational speed). In the example, the first circulation tank 16 and the second circulation tank 17 rotate at the same rotational speed, and the eighth and ninth rotational speeds are both set to 30 revolutions per minute (rpm).

[0103] The present disclosure does not limit the rotation directions of the impeller, the first circulation tank 16 and the second circulation tank 17 .

[0104] During the circulation process, while using the disperser for dispersion, the two circulation tanks are also rotated, so that the dispersion and mixing of the recovered electrode slurry can be more uniform, thereby improving the dispersion effect.

[0105] According to some embodiments of the present application, the slurry recovery method 200 further includes a process 500. Referring to FIG. 5 , the process 500 includes steps 510-520:

[0106] Step 510 , detecting the viscosity of the reusable slurry.

[0107] In step 520 , in response to the viscosity of the reusable slurry being within a predetermined viscosity range, the reusable slurry is added to a transfer tank (not shown) for reuse in the electrode coating process.

[0108] After the electrode slurry is recycled, the viscosity of the resulting reusable slurry may be tested to determine whether the reusable slurry can be used in an electrode coating process.

[0109] The preset viscosity range can be determined according to the requirements of the electrode coating process. In an example, the preset viscosity range can be set to 30-1500 mPa·s.

[0110] Step 510 may be completed manually using a corresponding detection method, or may be completed using an automated testing method, which is not limited in this disclosure.

[0111] After processing the recovered electrode slurry, the viscosity of the obtained reusable slurry is tested. When the use requirements are met, the reusable slurry can be reused, reducing the scrapping of the electrode slurry and improving the utilization rate.

[0112] According to some embodiments of the present application, the electrode coating process includes a gravure printing process. The electrode slurry includes an anode slurry.

[0113] During the electrode coating process, a gravure printing process can be used to apply the anode slurry. After the anode slurry is prepared, it is added to the feed tank and the electrode coating is completed using the gravure printing process. After a period of time, the anode slurry that has undergone physical gelation can be recycled to obtain a reusable slurry.

[0114] Recycling the anode slurry in the gravure printing process can achieve the reuse of the slurry and reduce the waste of anode slurry in the electrode coating process.

[0115] According to some embodiments of the present application, the anode slurry includes sodium carboxymethyl cellulose, styrene-butadiene emulsion, conductive carbon powder, and deionized water, and has a viscosity threshold of greater than or equal to 40 mPa·s and less than or equal to 60 mPa·s.

[0116] In the process of preparing the anode slurry, sodium carboxymethyl cellulose and conductive carbon powder may be mixed, and then further mixed with deionized water. After the mixture is uniformly mixed, styrene-butadiene emulsion is added and fully dispersed and mixed to obtain the anode slurry.

[0117] For the anode slurry, the viscosity threshold of the slurry recovery method 200 can be set to be greater than or equal to 40 mPa·s and less than or equal to 60 mPa·s. In an example, the viscosity threshold can be set to 50 mPa·s.

[0118] According to the materials included in the anode slurry, selecting an appropriate viscosity threshold to treat the recovered anode slurry accordingly can improve the quality of the resulting reusable slurry.

[0119] A specific embodiment of the present application is described below. It should be understood that this specific embodiment is described for illustrative purposes only and should not be construed as limiting the present application.

[0120] As shown in Figure 6, take the electrode coating process as the gravure printing process and the electrode slurry as the anode slurry as an example:

[0121] In step 602, the viscosity of the electrode slurry used in the electrode coating process, i.e., the viscosity of the anode slurry, is detected. The viscosity threshold is set to 50 mPa·s. After the viscosity of the electrode slurry is obtained, the relationship between the viscosity and the viscosity threshold is determined.

[0122] When the viscosity of the electrode slurry is not greater than 50 mPa·s, the electrode slurry is slurried according to a first slurrying process, which includes steps 604-616.

[0123] In step 604, the first raw material and the second raw material are dry-mixed in a premixing tank 14 to produce a premix. The first raw material may be sodium carboxymethyl cellulose, and the second raw material may be conductive carbon powder. As shown in Figure 1, the first raw material is added to a first raw material metering tank 11, and the second raw material is added to a second raw material metering tank 12. The first and second raw materials are transferred to the premixing tank 14 via a sending tank 13 for dry mixing to produce a premix.

[0124] In step 606, a solvent is added to the first circulation tank 16. The solvent may be deionized water.

[0125] In step 608, the solvent is transferred from the first circulation tank 16 to the disperser 15 via the first pipe 18, and the premix is ​​transferred from the premix tank 14 to the disperser 15 via the second pipe 19. The impeller of the disperser 15 rotates at a fifth speed to mix the premix with the solvent. The fifth speed may be 2250 rpm.

[0126] In step 610 , the mixture of the premix and the solvent is transferred from the disperser 15 to the first circulation tank 16 via the first pipe 18 .

[0127] In step 612, the mixture of the premix and the solvent is circulated between the first circulation tank 16 and the disperser 15 for a third time period to produce a premixed slurry. The impeller of the disperser 15 rotates at a fifth speed, which may be 2250 rpm. The first circulation tank 16 rotates at a sixth speed, which may be 30 rpm. The third time period may be 70 minutes.

[0128] In step 614, the premixed slurry is circulated between the first circulation tank 16 and the second circulation tank 17 via the first pipeline 18 for a second time period to obtain a coarse mixed slurry. The impeller of the disperser 15 rotates at a fourth speed, which may be 2250 rpm. The first circulation tank 16 and the second circulation tank 17 may also rotate at a speed of 30 rpm. The second time period may be 60 minutes.

[0129] In step 616, the crude mixed slurry, binder, and electrode slurry are circulated between the first circulation tank 16 and the second circulation tank 17 via the first pipeline 18 for a first duration to obtain a reusable slurry. The binder may be a styrene-butadiene emulsion. The impeller of the disperser 15 rotates at a first speed, which may be 1500 rpm. The first circulation tank 16 rotates at a second speed, and the second circulation tank 17 rotates at a third speed, which may be 30 rpm. The first duration may be 15 minutes.

[0130] In the first pulping process, the materials and weight ratios of the first raw material, the second raw material, the solvent and the binder may be as shown in Table 1:

[0131] Table 1 Materials and weight ratios of the first raw material, the second raw material, the solvent and the binder

[0132] In the first pulping process, the pulping temperature may be 5-65 degrees Celsius.

[0133] When the viscosity of the electrode slurry is greater than 50 mPa·s, the electrode slurry is slurried according to a second slurrying process, and the second slurrying process includes step 618 .

[0134] In step 618, the electrode slurry is circulated between the first circulation tank 16 and the second circulation tank 17 via the first pipe 18 for a fourth time period to obtain a reusable slurry. The impeller of the disperser 15 in the first pipe 18 rotates at a seventh speed, which may be 1500 rpm. The first circulation tank 16 rotates at an eighth speed, and the second circulation tank 17 rotates at a ninth speed, which may be 30 rpm. The fourth time period may be 15 minutes.

[0135] In the second pulping process, the pulping temperature may be 5-65 degrees Celsius.

[0136] After the reusable slurry is obtained, the viscosity of the reusable slurry is tested in step 620. During the testing process, the first circulation tank 16 and the second circulation tank 17 can be rotated at 30 rpm.

[0137] Based on the detected viscosity of the reusable slurry and a preset viscosity range, a determination is made as to whether the reusable slurry can be reused. The preset viscosity range may be 30-1500 mPa·s. In step 622, if the viscosity of the reusable slurry meets the preset viscosity range, the reusable slurry is added to a transfer tank for reuse in the electrode coating process.

[0138] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some or all of the technical features therein. These modifications or replacements do not deviate the essence of the corresponding technical solutions from the scope of the technical solutions of the embodiments of the present application, and they should all be included in the scope of the claims and specification of the present application. In particular, as long as there is no structural conflict, the various technical features mentioned in the various embodiments can be combined in any way. The present application is not limited to the specific embodiments disclosed herein, but includes all technical solutions that fall within the scope of the claims.

Claims

1. A slurry recovery method (200), comprising: Detect the viscosity of electrode slurry used in electrode coating process; In response to the viscosity of the electrode slurry being no greater than a viscosity threshold, slurrying the electrode slurry according to a first slurrying process to obtain a reusable slurry; or In response to the viscosity of the electrode slurry being greater than the viscosity threshold, the electrode slurry is slurried according to a second slurrying process to obtain a reusable slurry, Wherein, the second pulping process is different from the first pulping process.

2. The method (200) according to claim 1, wherein: The first pulping process includes: The coarse mixed slurry prepared from the powder and the solvent, the binder and the electrode slurry are circulated between the first circulation tank (16) and the second circulation tank (17) via the first pipe (18) for a first time period. The first pipe (18) connects the first circulation tank (16) and the second circulation tank (17), and a disperser (15) including an impeller is provided in the first pipe (18), and the impeller rotates at a first speed.

3. The method (200) according to claim 2, wherein: The step of circulating the coarse mixed slurry prepared from the powder and the solvent, the binder, and the electrode slurry between the first circulation tank (16) and the second circulation tank (17) via the first pipe (18) comprises: The first circulation tank (16) is rotated at a second rotational speed, and the second circulation tank (17) is rotated at a third rotational speed, wherein the second rotational speed and the third rotational speed are lower than the first rotational speed.

4. The method (200) according to claim 2 or 3, wherein: The powder includes a first raw material and a second raw material, and the first pulping process further includes the following steps to prepare the coarse mixed pulp: dry-mixing the first raw material and the second raw material in a premixing tank (14) to obtain a premix; mixing the premixture with the solvent to obtain a premixed slurry; as well as The premixed slurry is circulated between the first circulation tank (16) and the second circulation tank (17) via the first pipe (18) for a second time period to obtain the coarse mixed slurry, wherein the impeller rotates at a fourth speed, the fourth speed is greater than the first speed, and the second time period is greater than the first time period.

5. The method (200) according to claim 4, wherein: The disperser (15) is further connected to the premixing tank (14) via a second pipe (19) to mix the premix with the solvent to obtain the premixed slurry comprising: adding the solvent into the first circulation tank (16); The solvent is transferred from the first circulation tank (16) to the disperser (15) via the first pipe (18), and the premix is ​​transferred from the premix tank (14) to the disperser (15) via the second pipe (19), wherein the impeller rotates at a fifth speed to mix the premix with the solvent, and the fifth speed is greater than the first speed; transferring the mixture of the premix and the solvent from the disperser (15) to the first circulation tank (16) via the first pipe (18); and The mixture of the premixture and the solvent is circulated between the first circulation tank (16) and the disperser (15) for a third time period to obtain the premixed slurry, wherein the impeller rotates at the fifth speed and the third time period is greater than the first time period.

6. The method (200) according to claim 5, wherein: Circulating the mixture of the premix and the solvent between the first circulation tank (16) and the disperser (15) comprises: The first circulation tank (16) is rotated at a sixth rotational speed, which is lower than the first rotational speed.

7. The method (200) according to any one of claims 1 to 6, wherein: The second pulping process includes: circulate the electrode slurry between the first circulation tank (16) and the second circulation tank (17) via the first pipe (18) for a fourth time period, The first pipe (18) connects the first circulation tank (16) and the second circulation tank (17), and a disperser (15) including an impeller is provided in the first pipe (18), and the impeller rotates at a seventh speed.

8. The method (200) of claim 7, wherein: Circulating the electrode slurry between the first circulation tank (16) and the second circulation tank (17) via the first pipe (18) includes: The first circulation tank (16) is rotated at an eighth rotational speed, and the second circulation tank (17) is rotated at a ninth rotational speed, wherein the eighth rotational speed and the ninth rotational speed are lower than the seventh rotational speed.

9. The method (200) according to any one of claims 1 to 8, further comprising: detecting the viscosity of the recyclable slurry; as well as In response to the viscosity of the reusable slurry meeting a predetermined viscosity range, the reusable slurry is added to a transfer tank for reuse in the electrode coating process.

10. The method (200) according to any one of claims 1 to 9, wherein: The electrode coating process includes a gravure printing process, and the electrode slurry includes an anode slurry.

11. The method (200) according to claim 10, wherein: The anode slurry includes sodium carboxymethyl cellulose, styrene-butadiene emulsion, conductive carbon powder and deionized water, and the viscosity threshold is greater than or equal to 40 mPa·s and less than or equal to 60 mPa·s.

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