An electrode powder, a method for producing the same, and use thereof

Abstract

The application belongs to the technical field of electrode processing and manufacturing. The application provides an electrode powder, a preparation method and an application thereof. The preparation method comprises the following steps: sequentially performing vibration dispersion and vibration granulation on a fibrillated powder obtained by a dry electrode technology, so as to obtain the electrode powder. The application performs dispersion and secondary granulation in a vibration mode, so as to form the electrode powder with a certain fluidity. The electrode powder can be used to continuously produce a continuous film with uniform thickness and density when being rolled into a film, and the adhesion and tensile strength are not affected, so that the production quality, production efficiency and the performance of the obtained electrode are improved.

Description

Technical Field

[0001] This invention belongs to the field of electrode processing and preparation technology, and relates to an electrode powder, its preparation method and application. Background Technology

[0002] With the rapid development of the new energy industry, higher requirements have been placed on the processing technology of devices such as capacitors and secondary batteries. During the electrode preparation process, factors such as raw materials, equipment, processes, environment, and production control standards all affect the production efficiency and quality of electrode products, requiring precise control of the process and strict standardization of the products.

[0003] Currently, in the electrode preparation process of capacitors and secondary batteries, the wet process of coating a mixed slurry (made using liquid solvents or dispersants) onto a substrate is widely used to prepare the electrode sheet. However, the recovery of the liquid will greatly increase energy consumption, and during the drying and recovery process of the liquid phase system, the coating structure will inevitably change and deviate from the target design state. This uncontrollability of the coating structure will also have a serious impact on the performance of the electrode sheet.

[0004] Compared to wet processes, the implementation of dry electrode technology can greatly avoid the energy consumption caused by slurry preparation and liquid recovery, and is conducive to shortening the processing steps. Because dry electrode technology uses little or no liquid, its electrode structure can better meet the requirements of designability and stability.

[0005] Typically, the process route for dry electrode technology involves dry mixing the active material, conductive agent, fiberizable binder, and other additives in one or several steps. The uniformly mixed powder is then stored at high temperature, causing the binder to expand due to heat, transforming the dense particles into loose clumps. Under high-speed shearing force, the granular binder forms fibers, resulting in a fibrillated powder. This powder is then used for roll forming to produce dry electrode sheets.

[0006] However, in the conventional dry electrode process described above, the fibrous binder is mixed with the active material and other powders. Due to the fibrous state of the binder, the mixed powder is prone to forming clumps or flocs during stirring. This makes it difficult to meter the feed and fails to meet the uniformity requirements during subsequent roll forming. Extremely high roll forming pressure is often required to squeeze and extend the flocs or clumps to form a continuous film. It is precisely because of the agglomeration of the clumps or flocs in the mixed powder that the continuity and uniformity of the physical properties of the electrode sheet, such as thickness, density, and tensile strength, are difficult to guarantee.

[0007] Existing technologies disclose a method for processing electrode materials and electrode sheets, which includes stirring fibrous materials at a low speed of 100-500 rpm to disperse them, thereby facilitating roller feeding and the formation of a continuous and uniform film to some extent; another prior art discloses a method for preparing dry electrode sheets, which includes shearing and granulating fibrous materials at a low speed of 400-600 rpm to form 1 cm particles, thereby facilitating roller feeding and the formation of a continuous and uniform film to some extent.

[0008] However, in the above dry electrode technology, the bonding effect relies on the fiberized binder to connect the components. If the binder that has already undergone fiberization is further stirred and dispersed, its fiberized structure will be destroyed by shear force, the fibers will be further shortened or even over-fiberized, resulting in a serious reduction in the strength of the binder fibers. As a result, effective cross-linking and bonding cannot be formed between the short fibers, ultimately causing a decrease in the macroscopic strength of the electrode film, which in turn affects the performance of the electrode.

[0009] Therefore, it is necessary to provide a new method for processing powder after dry electrode fiberization and a new method for dry electrode processing. Summary of the Invention

[0010] In view of the problems existing in the prior art, the purpose of this invention is to provide an electrode powder, its preparation method, and its uses. The preparation method involves sequentially vibrating and dispersing the fibrillated powder obtained by dry electrode technology and then vibrating and granulating it to obtain the electrode powder. By dispersing and granulating it through vibration, an electrode powder with a certain degree of fluidity is formed. This allows for the continuous production of continuous films with uniform thickness and density during roll forming, while ensuring that the adhesion and tensile strength are not affected, thereby improving production quality, production efficiency, and the performance of the resulting electrode.

[0011] To achieve this objective, the present invention adopts the following technical solution:

[0012] In a first aspect, the present invention provides a method for preparing electrode powder, comprising: dry mixing electrode raw materials to obtain fibrillated powder; and sequentially subjecting the fibrillated powder to vibration dispersion and vibration granulation to obtain electrode powder.

[0013] This invention disperses and granulates the material through vibration. Vibration dispersion breaks up the flocculent and clump-like substances in the fibrillated powder, further optimizing the uniform mixing of the components. Vibration granulation re-agglomerates the uniformly dispersed raw materials into uniform secondary particles, providing a foundation for the consistency and uniformity of subsequent roll forming. While facilitating processing, it also makes the electrode film layer more uniform and improves electrochemical performance such as cycling.

[0014] In summary, the combination of vibration dispersion and vibration granulation ultimately forms an electrode powder with a certain degree of fluidity. This allows for the production of continuous films with uniform thickness and density during roll forming, while ensuring that adhesion and tensile strength remain unaffected. Furthermore, the resulting electrode powder is easy to feed and meter, thereby improving production quality, production efficiency, and the performance of the resulting electrodes.

[0015] The following are preferred technical solutions of the present invention, but are not intended to limit the technical solutions provided by the present invention. The technical objectives and beneficial effects of the present invention can be better achieved and realized through the following technical solutions.

[0016] As a preferred technical solution of the present invention, the electrode raw material includes an active main material, a conductive agent and a binder; the dry mixing process includes: mixing the electrode raw material and then dry mixing to obtain a mixed powder, and subjecting the mixed powder to heat treatment and high-speed shearing in sequence to fiberize the binder to obtain fibrillated powder.

[0017] Preferably, the adhesive comprises at least one of PTFE (polytetrafluoroethylene), PE (polyethylene), PP (polypropylene) or PEO (polyethylene oxide), for example typical but non-limiting examples of combinations include combinations of PTFE and PE, PTFE and PEO, PTFE and PP, PE and PP, PEO and PP, or PEO and PE, etc.

[0018] It is understood that the adhesive described in this invention is a fiberizable adhesive, and thus can be fiberized through heat treatment and high-speed shearing.

[0019] Furthermore, this invention does not limit the specific material selection and dosage of the active main material and the conductive agent, nor does it limit the dosage of the binder. The active main material can be a positive electrode active material or a negative electrode active material, so that the final electrode is a positive electrode or a negative electrode. Further, the electrode raw materials of this invention may also include other excipients or additives, which can be reasonably adjusted and selected by those skilled in the art according to design objectives and actual needs.

[0020] As a preferred technical solution of the present invention, the dry mixing process includes: first mixing the active main material with the conductive agent and then performing a first dry mixing to obtain a first mixed powder; then mixing the first mixed powder with the binder and then performing a second dry mixing to obtain a second mixed powder.

[0021] Preferably, the rotation speed of the first dry mixing is 400-600 rpm, such as 400 rpm, 430 rpm, 450 rpm, 480 rpm, 500 rpm, 530 rpm, 550 rpm, 580 rpm or 600 rpm, and the time is 20-40 min, such as 20 min, 23 min, 25 min, 28 min, 30 min, 33 min, 35 min, 38 min or 40 min.

[0022] Preferably, after the first mixed powder is cooled and dry-mixed, it is then mixed with the binder and subjected to a second dry-mixing; the temperature of the cooling and dry-mixing is 0-10℃, for example, 0℃, 1℃, 2℃, 3℃, 4℃, 5℃, 6℃, 7℃, 8℃, 9℃ or 10℃, etc., the rotation speed is 50-150 rpm, for example, 50 rpm, 60 rpm, 70 rpm, 80 rpm, 90 rpm, 100 rpm, 110 rpm, 120 rpm, 130 rpm, 140 rpm or 150 rpm, etc., and the time is 5-15 min, for example, 5 min, 6 min, 7 min, 8 min, 9 min, 10 min, 11 min, 12 min, 13 min, 14 min or 15 min, etc.

[0023] Preferably, the rotation speed of the second dry mixing is 700-900 rpm, such as 700 rpm, 730 rpm, 750 rpm, 780 rpm, 800 rpm, 830 rpm, 850 rpm, 880 rpm or 900 rpm, and the time is 10-60 min, such as 10 min, 15 min, 20 min, 25 min, 30 min, 35 min, 40 min, 45 min, 50 min, 55 min or 60 min.

[0024] Preferably, the temperature of the second dry mix is ​​lower than the softening point of the binder.

[0025] It should be noted that during the dry mixing process to obtain the mixed powder, the temperature subjected to the binder should be kept below its softening point to avoid fiberization of the binder during dry mixing. Therefore, in order to control the temperature when the binder is added, the present invention preferably performs cooling dry mixing of the first mixed powder to reduce and stabilize the bulk temperature.

[0026] As a preferred embodiment of the present invention, the heat treatment temperature is 90-100℃, such as 90℃, 91℃, 92℃, 93℃, 94℃, 95℃, 96℃, 97℃, 98℃, 99℃ or 100℃, and the time is 30-180min, such as 30min, 40min, 50min, 60min, 70min, 80min, 90min, 100min, 110min, 120min, 130min, 140min, 150min, 160min, 170min or 180min.

[0027] As a preferred technical solution of the present invention, the high-speed shearing speed is 8000-9000 rpm, such as 8000 rpm, 8100 rpm, 8200 rpm, 8300 rpm, 8400 rpm, 8500 rpm, 8600 rpm, 8700 rpm, 8800 rpm, 8900 rpm or 9000 rpm, and the time is 5-10 min, such as 5 min, 6 min, 7 min, 8 min, 9 min or 10 min.

[0028] As a preferred technical solution of the present invention, the vibration mode of vibration dispersion and vibration granulation includes ultrasonic vibration and / or mechanical vibration.

[0029] Preferably, the vibration dispersion and vibration granulation use a vibrating screen of 80 to 150 mesh, such as 80 mesh, 90 mesh, 100 mesh, 110 mesh, 120 mesh, 130 mesh, 140 mesh or 150 mesh.

[0030] Preferably, the number of vibrating screens used for vibration dispersion and vibration granulation is independently 1 to 3, for example, 1, 2 or 3.

[0031] In this invention, based on experience, using 1 to 3 vibrating screens for vibration dispersion and vibration granulation is sufficient to achieve excellent dispersion and secondary granulation effects. Of course, depending on the needs, more than 3 vibrating screens can be used for vibration dispersion and vibration granulation. When using at least 2 vibrating screens, they are preferably stacked vertically, so that the material from the upper vibrating screen falls directly into the lower vibrating screen.

[0032] Preferably, the mesh size of the vibrating screen increases sequentially along the material discharge direction of the vibration dispersion.

[0033] Preferably, the mesh size of the vibrating screen is the same along the material discharge direction of the vibratory granulation.

[0034] Preferably, the maximum mesh size of the vibrating screen used for vibratory granulation is not greater than the maximum mesh size of the vibrating screen used for vibratory dispersion.

[0035] In this invention, the mesh size of the vibrating screen used for vibration dispersion gradually decreases to facilitate the dispersing of flocculent powder. Conversely, the mesh size of the vibrating screen used for vibration granulation is larger to facilitate secondary granulation.

[0036] Preferably, the vibration direction of the vibration dispersion includes vertical vibration, and the vibration direction of the vibration granulation includes horizontal vibration.

[0037] In this invention, vertical vibration refers to the up-and-down vibration perpendicular to the screen surface (along the material drop direction) when the material is received on the screen surface of the vibrating screen, causing the material to "jump" up and down; horizontal vibration refers to the "rolling" of the material on the screen surface (perpendicular to the material drop direction) back and forth or left and right.

[0038] In a second aspect, the present invention provides an electrode powder obtained according to the preparation method described in the first aspect.

[0039] As a preferred embodiment of the present invention, the electrode powder is a secondary particle.

[0040] Preferably, the repose angle of the electrode powder of the secondary particles is ≤35°, such as 35°, 32°, 30°, 28°, 25°, 22°, 20°, 18°, 16°, 13°, 10°, 8°, 5°, 3° or 1°.

[0041] Thirdly, the present invention provides an electrode comprising the electrode powder described in the second aspect.

[0042] Fourthly, the present invention provides a method for manufacturing the electrode described in the third aspect, wherein the electrode powder described in the third aspect is rolled into a continuous self-supporting electrode film, and then the continuous self-supporting electrode film and a substrate are rolled into an electrode.

[0043] Fifthly, the present invention provides an application of the electrode described in the third aspect, the application including a secondary battery or a supercapacitor.

[0044] Due to space limitations and to avoid redundancy, this invention does not list all point values ​​within the above numerical range, but it is not limited to the listed values ​​either; other unlisted values ​​within the above numerical range are also applicable.

[0045] Compared with existing technical solutions, the present invention has at least the following beneficial effects:

[0046] This invention obtains fibrillated powder through a dry process, which is then subjected to vibration dispersion and vibration granulation to obtain electrode powder. The dispersion and secondary granulation via vibration create electrode powder with a certain degree of flowability. This allows for the continuous production of continuous films with uniform thickness and density during roll forming, while ensuring that adhesion and tensile strength remain unaffected. Furthermore, the resulting electrode powder facilitates feeding and metering, thereby improving production quality, efficiency, and the performance of the resulting electrodes. Attached Figure Description

[0047] Figure 1 This is a schematic flowchart of the electrode powder preparation method in Example 1;

[0048] Figure 2 This is a schematic flowchart of a method for manufacturing an electrode containing the electrode powder described in this invention.

[0049] Figure 3 This is a schematic diagram of the ultrasonic vibrating screen in Example 1. Detailed Implementation

[0050] The technical solution of the present invention will be further illustrated below through specific embodiments.

[0051] Those skilled in the art will understand that the embodiments described are merely illustrative of the invention and should not be construed as limiting the invention.

[0052] Example 1

[0053] This embodiment provides a method for preparing electrode powder, such as... Figure 1 As shown, the preparation method includes:

[0054] (1) Weigh out the active substrate NCM811, conductive agent carbon black and binder PTFE powder in a mass ratio of 96.5:2:1.5; add the active substrate and conductive agent to a stirrer and perform a first dry mix at 500 rpm for 30 min at room temperature to obtain a first mixed powder; use low temperature cooling water to control the temperature and perform a cooling dry mix at 100 rpm for 10 min below 10℃ to obtain a cooled mixed powder; add the binder to the stirrer to mix the cooled mixed powder with the binder, and perform a second dry mix at 800 rpm for 35 min, controlling the temperature of the second dry mix to be lower than the softening point of the binder to avoid premature fiberization of the binder, to obtain a second mixed powder;

[0055] (2) The obtained second mixed powder was heat-treated in an oven at 95°C for 110 min, and then subjected to high-speed shearing at a stirring speed of 8500 rpm for 8 min to fiberize the binder and obtain fibrillated powder.

[0056] (3) Prepare an ultrasonic vibrating screen, such as Figure 3 As shown, four ultrasonic vibrating screens are stacked from top to bottom, with mesh sizes of 80 mesh, 150 mesh, 150 mesh, and 150 mesh respectively. The screen surfaces are horizontal, and adjacent upper and lower vibrating screens are connected by elastic connectors. The first two ultrasonic vibrating screens vibrate vertically up and down, while the last two ultrasonic vibrating screens vibrate horizontally back and forth.

[0057] The obtained fibrillated powder is placed in the uppermost ultrasonic vibrating screen, so that the fibrillated powder is vibrated and dispersed in the first two ultrasonic vibrating screens during the feeding process, and vibrated and granulated in the last two ultrasonic vibrating screens, finally obtaining electrode powder of secondary particles under the screen, the angle of repose of the electrode powder is 15.4°.

[0058] Example 2

[0059] This embodiment provides a method for preparing electrode powder, the method comprising:

[0060] (1) Weigh out active substrate graphite, conductive agent SP and binder PTFE powder in a mass ratio of 97%:1.5%:1.5%; add the active substrate and conductive agent to a stirrer and perform a first dry mix at 400 rpm for 40 min at room temperature to obtain a first mixed powder; use low temperature cooling water to control the temperature and perform a cooling dry mix at 50 rpm for 15 min below 10℃ to obtain a cooled mixed powder; add the binder to the stirrer to mix the cooled mixed powder with the binder, and perform a second dry mix at 700 rpm for 45 min, controlling the temperature of the second dry mix to be lower than the softening point of the binder to avoid premature fiberization of the binder, to obtain a second mixed powder;

[0061] (2) The obtained second mixed powder was heat-treated in an oven at 90°C for 180 min, and then subjected to high-speed shearing at a stirring speed of 8000 rpm for 10 min to fiberize the binder and obtain fibrillated powder.

[0062] (3) Prepare an ultrasonic vibrating screen. Three ultrasonic vibrating screens are stacked from top to bottom, with mesh sizes of 80 mesh, 150 mesh, and 150 mesh respectively. The screen surface is horizontal. The first two ultrasonic vibrating screens vibrate vertically up and down, and the third ultrasonic vibrating screen vibrates horizontally back and forth.

[0063] The obtained fibrillated powder is placed in the uppermost ultrasonic vibrating screen, so that the fibrillated powder is vibrated and dispersed in the first two ultrasonic vibrating screens during the feeding process, and vibrated and granulated in the third ultrasonic vibrating screen, finally obtaining the electrode powder under the screen, the angle of repose of the electrode powder is 15.4°.

[0064] Example 3

[0065] This embodiment provides a method for preparing electrode powder, the method comprising:

[0066] (1) Weigh out the active substrate MgTiO3, activated carbon and binder PTFE powder in a mass ratio of 95%:3%:2%; add the active substrate and conductive agent to a stirrer and perform a first dry mix at 600 rpm for 20 min at room temperature to obtain a first mixed powder; use low temperature cooling water to control the temperature and perform a cooling dry mix at 150 rpm for 5 min below 10℃ to obtain a cooled mixed powder; add the binder to the stirrer to mix the cooled mixed powder with the binder, and perform a second dry mix at 900 rpm for 25 min, controlling the temperature of the second dry mix to be lower than the softening point of the binder to avoid premature fiberization of the binder, to obtain a second mixed powder;

[0067] (2) The obtained second mixed powder was heat-treated in an oven at 100°C for 80 min, and then subjected to high-speed shearing at a stirring speed of 8000 rpm for 5 min to fiberize the binder and obtain fibrillated powder.

[0068] (3) Prepare an ultrasonic vibrating screen. Five ultrasonic vibrating screens are stacked from top to bottom, with mesh sizes of 80 mesh, 120 mesh, 150 mesh, 150 mesh and 150 mesh respectively. The screen surface is horizontal. The first three ultrasonic vibrating screens vibrate vertically up and down, and the last two ultrasonic vibrating screens vibrate horizontally back and forth.

[0069] The obtained fibrillated powder is placed in the uppermost ultrasonic vibrating screen, so that the fibrillated powder is vibrated and dispersed in the first three ultrasonic vibrating screens during the feeding process, and vibrated and granulated in the last two ultrasonic vibrating screens, finally obtaining the electrode powder under the screen, the angle of repose of the electrode powder is 15.7°.

[0070] Example 4

[0071] This embodiment provides a method for preparing electrode powder. In step (1), the first mixed powder is directly subjected to a second dry mixing without cooling. The resulting electrode powder has a repose angle of 23.4°. Except for the above, the other conditions are exactly the same as in Example 1.

[0072] Example 5

[0073] This embodiment provides a method for preparing electrode powder. In step (2), no heat treatment is performed; instead, high-speed shearing is directly applied. The angle of repose of the electrode powder is 15.1°. Except for the above, all other conditions are exactly the same as in Example 1.

[0074] Example 6

[0075] This embodiment provides a method for preparing electrode powder. In step (2), the high-speed shearing time is adjusted from 8 min to 15 min, and the angle of repose of the electrode powder is 11.3°. Except for the above, the other conditions are exactly the same as in Example 1.

[0076] Example 7

[0077] This embodiment provides a method for preparing electrode powder. In step (3), a mechanical vibrating screen is used instead of an ultrasonic vibrating screen, and the angle of repose of the electrode powder is 14.6°. Except for the above, all other conditions are exactly the same as in Embodiment 1.

[0078] Example 8

[0079] This embodiment provides a method for preparing electrode powder. In step (3), the number of ultrasonic vibrating screens is reduced from four to two, with mesh sizes of 150 mesh and 150 mesh respectively. The first ultrasonic vibrating screen vibrates vertically up and down, while the second ultrasonic vibrating screen vibrates horizontally back and forth. Vibration dispersion is performed and completed in the first ultrasonic vibrating screen, and vibration granulation is performed and completed in the second ultrasonic vibrating screen. Finally, electrode powder is obtained from the screens, and the angle of repose of the electrode powder is 28.2°. Except for the above, all other conditions are exactly the same as in Example 1.

[0080] Example 9

[0081] This embodiment provides a method for preparing electrode powder. In step (3), the number of ultrasonic vibrating screens is adjusted from 4 to 6, with mesh sizes of 80 mesh, 120 mesh, 150 mesh, 150 mesh, 150 mesh, and 150 mesh respectively. The first three ultrasonic vibrating screens vibrate vertically up and down, while the last three vibrate horizontally back and forth. Vibration dispersion is performed and completed in the first three ultrasonic vibrating screens, and vibration granulation is performed and completed in the last three ultrasonic vibrating screens. Finally, electrode powder is obtained from the screens, and the angle of repose of the electrode powder is 11.4°. Except for the above, other conditions are exactly the same as in Embodiment 1.

[0082] Comparative Example 1

[0083] This comparative example provides a method for preparing electrode powder, wherein step (3) is omitted, and the fibrillated powder obtained in step (2) is used directly. The electrode powder does not have flowability, and the angle of repose cannot be measured. Except for the above, the other conditions are exactly the same as in Example 1.

[0084] Comparative Example 2

[0085] This comparative example provides a method for preparing electrode powder, wherein step (3) is omitted, and the fibrillated powder obtained in step (2) is used directly. The angle of repose of the electrode powder is 38.4°. Except for the above, the other conditions are exactly the same as in Example 2.

[0086] Comparative Example 3

[0087] This comparative example provides a method for preparing electrode powder, wherein step (3) is omitted, and the fibrillated powder obtained in step (2) is used directly. The angle of repose of the electrode powder is 42.1°. Except for the above, all other conditions are exactly the same as in Example 3.

[0088] Comparative Example 4

[0089] This comparative example provides a method for preparing electrode powder. In step (3), the preparation method only involves vibration dispersion and does not involve vibration granulation. The sample obtained by vibration dispersion is used directly. Except for the above, the other conditions are exactly the same as in Example 1. The angle of repose of the electrode powder is 62.7°.

[0090] Comparative Example 5

[0091] This comparative example provides a method for preparing electrode powder. In step (3), the vibration dispersion and vibration granulation are not performed. Instead, the fibrillated powder obtained in step (2) is stirred at a low speed of 300 rpm to disperse it. Except for the above, the other conditions are exactly the same as in Example 1. The electrode powder does not have fluidity and the angle of repose cannot be measured.

[0092] Application Example 1

[0093] The electrode powders obtained in Examples 1-9 and Comparative Examples 1-5 were used to manufacture electrodes, such as... Figure 2 As shown, the method for manufacturing the electrode includes placing the electrode powder in a dry powder metering and feeding system to accurately measure the feeding amount, pre-pressing it into a film by roller pressing, then performing multi-stage thinning through multiple roller pressings to form a uniform and continuous self-supporting electrode film, and then combining the self-supporting electrode film with a substrate by roller pressing to form an electrode.

[0094] The obtained electrodes were subjected to diaphragm tension strength and areal density fluctuation tests. The diaphragm strength was tested using a universal tensile testing machine. Circular samples with a diameter of 5 cm were cut along the width and length directions. The areal density of the samples was calculated, and the difference between the maximum and minimum values ​​was taken to calculate the areal density fluctuation range. The results are recorded in Table 1.

[0095] Table 1

[0096] Electrode powder diaphragm tensile strength (N / m) Surface density fluctuation in width direction / 80cm Surface density fluctuation along length direction / 10m Example 1 25 0.1％ 0.020％ Example 2 6 0.08％ 0.015％ Example 3 22 0.11％ 0.018％ Example 4 7 1.2％ 0.032％ Example 5 12 0.2％ 0.025％ Example 6 18 0.1％ 0.018％ Example 7 23 0.1％ 0.022％ Example 8 8 0.3％ 3％ Example 9 24 0.11％ 0.019％ Comparative Example 1 5 2.2％ 2.300％ Comparative Example 2 0.5 1.3％ 1.1％ Comparative Example 3 4 2.4％ 1.8％ Comparative Example 4 8 0.5％ 2.4％ Comparative Example 5 12 4.2％ 1.200％

[0097] As can be seen from Table 1:

[0098] Due to the inherent properties of the graphite anode, the tensile strength of Example 2 is lower than that of Example 1; and during roll forming, the areal density fluctuates less due to the self-lubricating properties of graphite itself.

[0099] The physical properties of the main material in Example 3 are similar to those in Example 1, therefore their membrane properties are similar;

[0100] In Example 4, the absence of cooling water caused the binder to become fibrous during mixing and stirring. When it was fibrousized again at high speed, the binder was over-fiberized, its fiber length was shortened, and the strength of the film formed was low.

[0101] In Example 5, there was no heat treatment process, the fiberization of the binder was insufficient, and the strength of the film formed was low.

[0102] In Example 6, the binder was stirred at high speed for too long, resulting in excessive fiberization, which caused the fibers to break and the resulting film to have low strength.

[0103] In Example 7, mechanical vibration was used. The dispersion and granulation effects were similar to those of ultrasonic vibration, but the dispersion and granulation effects were not as good as those of ultrasonic vibration. The secondary structure inside the particles could not be dispersed, and the homogenization was insufficient. Therefore, the tensile strength of the membrane decreased slightly.

[0104] In Example 8, the number of sieve layers resulted in poor dispersion and granulation effects, leading to uneven material distribution during membrane rolling, resulting in poor areal density consistency and low strength.

[0105] In Example 9, the use of more layers of sieves significantly improved dispersion and granulation, but did not significantly enhance the performance of the membrane.

[0106] Therefore, reasonable stirring, dispersion, and granulation methods can be used to prepare electrode films with high tensile strength and good film consistency.

[0107] In summary, the preparation method described in this invention breaks down and disperses the flocculent structure of the fibrillated powder after vibration dispersion. After vibration granulation, due to the properties of the fiber itself, it agglomerates into small particles when vibrating left and right and passes through a sieve to form uniform spherical secondary particles of electrode powder. Using this electrode powder, a continuous, uniform, and consistent thickness self-supporting electrode film can be prepared, and further composited to form an electrode sheet.

[0108] Application Example 2

[0109] The electrodes obtained in Application Example 1 from Examples 1, 2, 4-9 and Comparative Examples 1, 2, 4 and 5 are used as positive or negative electrode sheets to assemble a battery. The battery assembly method includes cutting the above-mentioned positive electrode sheet into a raw sheet with a diameter of 12 mm, and using the negative electrode sheet obtained from Example 2 as the counter electrode to assemble a CR2032 button battery.

[0110] The obtained batteries were tested, and the results are recorded in Table 2.

[0111] Table 2

[0112]

[0113]

[0114] As can be seen from Table 2:

[0115] The positive electrode prepared in Example 1 and the negative electrode prepared in Example 2 exhibited relatively high first-efficiency and cycle retention rates. The uniformity of the electrode sheet (macroscopically) is positively correlated with the granulation effect; therefore, uniform material dispersion is required. Fluctuations in tension and length only represent the difficulty of processing and the consistency of the cell. Referring to the results of Example 8 in Table 1, although the ultrasonic vibration in Example 8 cannot guarantee the granulation effect, it can ensure material uniformity; therefore, the cycle capacity of the cell itself will not deteriorate excessively. In Comparative Example 4, the lack of cooling water damages the material structure, thus worsening the cycle retention rate.

[0116] Application Example 3

[0117] The electrodes obtained from Example 3 and Comparative Example 3 in Application Example 1 are assembled into a supercapacitor. The assembly method of the supercapacitor includes cutting the above-mentioned electrode sheets into original sheets with a diameter of 12 mm and assembling them into a CR2032 button cell with symmetrical electrodes.

[0118] The obtained supercapacitor was tested, and the results are recorded in Table 3.

[0119] Table 3

[0120] electrode 5A / 1A Capacity Retention Rate Example 3 99 Comparative Example 3 87

[0121] As can be seen from Table 3:

[0122] The capacitor assembled in Example 3 has even better rate performance.

[0123] As can be seen from the above, this invention obtains fibrillated powder through a dry process, which is then subjected to vibration dispersion and vibration granulation to obtain electrode powder. The dispersion and secondary granulation via vibration create electrode powder with a certain degree of fluidity. This allows for the continuous production of continuous films with uniform thickness and density during roll forming, while ensuring that adhesion and tensile strength remain unaffected. Furthermore, the resulting electrode powder facilitates feeding and metering, thereby improving production quality, efficiency, and the performance of the resulting electrodes.

[0124] This invention illustrates the detailed process equipment and process flow through the above embodiments. However, this invention is not limited to the detailed process equipment and process flow described above, meaning that this invention does not necessarily depend on the detailed process equipment and process flow to be implemented. Those skilled in the art should understand that any improvements to this invention, equivalent substitutions of raw materials for the product of this invention, addition of auxiliary components, and selection of specific methods, all fall within the protection scope and disclosure scope of this invention.

[0125] The preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited to the specific details in the above embodiments. Within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solution of the present invention, and these simple modifications all fall within the protection scope of the present invention.

[0126] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present invention will not describe the various possible combinations separately.

[0127] Furthermore, various different embodiments of the present invention can be combined in any way, as long as they do not violate the spirit of the present invention, they should also be regarded as the content disclosed by the present invention.

Claims

1. A method for producing an electrode powder having a rest angle of < 35°, characterized in that The electrode raw material is dry mixed to obtain fibrillated powder; the fibrillated powder is subjected to vibration dispersion and vibration granulation in sequence to obtain electrode powder. The vibration direction of the vibration dispersion includes vertical vibration, and the vibration direction of the vibration granulation includes horizontal vibration. The electrode raw material includes active main material, conductive agent and binder; the process of the dry mixing includes: after the electrode raw material is mixed, dry mixing is performed to obtain mixed powder, and the mixed powder is subjected to heat treatment and high-speed shearing in sequence to make the binder fibrillated to obtain fibrillated powder.

2. The method of claim 1, wherein the electrode powder is prepared by a process comprising: The binder includes at least one of polytetrafluoroethylene, polyethylene, polypropylene or polyethylene oxide.

3. The method of claim 2, wherein the step of mixing is performed at a temperature of 20°C to 40°C. The process of the dry mixing includes: first, the active main material and the conductive agent are mixed to perform first dry mixing to obtain first mixed powder, and then the first mixed powder and the binder are mixed to perform second dry mixing to obtain second mixed powder.

4. The method of claim 2, wherein the electrode powder is prepared by a process comprising: The rotation speed of the first dry mixing is 400-600 rpm, and the time is 20-40 min.

5. The method of claim 4, wherein the electrode powder is prepared by a process comprising: After the first mixed powder is subjected to cooling dry mixing, the first mixed powder is mixed with the binder and subjected to second dry mixing; the temperature of the cooling dry mixing is 0-10 ℃, the rotation speed is 50-150 rpm, and the time is 5-15 min.

6. The method of claim 4, wherein the electrode powder is prepared by a process comprising: The rotation speed of the second dry mixing is 700-900 rpm, and the time is 10-60 min.

7. The method of claim 4, wherein the electrode powder is prepared by a process comprising: The temperature of the second dry mixing is less than the softening point of the binder.

8. The method of claim 4, wherein the electrode powder is prepared by a process comprising: The temperature of the heat treatment is 90-100 ℃, and the time is 30-180 min.

9. The method of claim 2, wherein the electrode powder is prepared by a process comprising: The rotation speed of the high-speed shearing is 8000-9000 rpm, and the time is 5-10 min.

10. The method of claim 2, wherein the electrode powder is prepared by a process comprising: The vibration mode of the vibration dispersion and the vibration granulation includes ultrasonic vibration and / or mechanical vibration.

11. A method of producing an electrode powder according to any one of claims 2 to 10, characterized in that, The vibration dispersion and the vibration granulation use vibration screens with 80-150 mesh.

12. A method of producing an electrode powder according to any one of claims 2 to 10, characterized in that, The number of the vibration screens used in the vibration dispersion and the vibration granulation is independently 1-3.

13. The method of claim 12, wherein the electrode powder is prepared by a process comprising: Along the falling direction of the vibration dispersion, the mesh of the vibration screens increases in sequence.

14. The method of claim 12, wherein the electrode powder is prepared by a process comprising: Along the falling direction of the vibration granulation, the mesh of the vibration screens is the same.

15. The method of claim 12, wherein the electrode powder is prepared by a process comprising: The maximum mesh of the vibration screens of the vibration granulation is not greater than the maximum mesh of the vibration screens of the vibration dispersion.

16. The method of claim 12, wherein the electrode powder is prepared by a process comprising: The preparation method according to any one of claims 1-16.

17. An electrode powder, characterized by The electrode powder is secondary particles.

18. The electrode powder of claim 17, wherein, The electrode powder of the secondary particles has an angle of repose of ≤35°.

19. The electrode powder of claim 18, wherein, The electrode powder contains the electrode powder according to any one of claims 17-19.

20. An electrode, characterized by The electrode powder according to any one of claims 17-19 is rolled into an electrode film, and the electrode film is rolled with a substrate into an electrode.

21. A method of manufacturing the electrode of claim 20, wherein The use includes secondary batteries or supercapacitors.

22. Use of an electrode according to claim 20, characterized in that ​

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