Method and system for representing film-forming performance of powder after dry-method electrode fibrillation

Abstract

The invention discloses a method and system for representing the film-forming performance of powder after dry-method electrode fibrillation, and the method comprises the following steps: S1, uniformly mixing a positive electrode material or a negative electrode material of a lithium / sodium ion battery, a conductive agent and a binder under a solvent-free condition, and then carrying out fibrillation to obtain dry-method electrode powder, sampling the dry-method electrode powder to obtain dry-method electrode powder to be detected; s2, measuring the maximum diffusion diameter A of the bottom surface of the to-be-measured dry-method electrode powder and the height B of the to-be-measured dry-method electrode powder in the vertical direction after the to-be-measured dry-method electrode powder is pressed and vibrated, and calculating the filming degree W of the dry-method electrode powder, and S3, judging whether the filming degree value W of the to-be-measured dry-method electrode powder meets the standard for preparing a dry-method diaphragm or not. According to the invention, whether the dry-method electrode powder can be made into the membrane can be rapidly represented, and the problems that the existing dry-method electrode detection method is lack and the dry powder material cannot be represented are solved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of dry electrodes and lithium ion batteries, and particularly relates to a method and system for characterizing film-forming performance of powder after fibrillation of a dry electrode, a computer device, a storage medium and a program product. BACKGROUND

[0002] With the explosive growth of the global new energy vehicle and energy storage industries, lithium-ion batteries, as core power sources and energy storage media, are facing fierce competition for performance improvement and cost control. While the traditional wet electrode process (slurry coating) is mature and stable, it faces inherent bottlenecks such as high energy consumption (solvent drying), pollution risks (organic solvent use and recovery), complex equipment, and rising costs. Against this backdrop, dry electrode technology, with its disruptive process—solvent-free, direct electrode preparation through dry powder mixing, fiberization, and hot pressing—is considered a strategic direction for the next generation of high-performance, low-cost, and more environmentally friendly battery manufacturing. The core appeal of the dry process lies in its revolutionary process simplification and potential cost and environmental advantages: complete elimination of solvents, significant energy reduction, broad material compatibility, high theoretical loading, and high rate capability. However, the core step of the dry process—powder fiberization (fibrillation of the binder PTFE through high-intensity mechanical action to form a network structure encapsulating the active material and conductive agent)—introduces complex microstructural evolution far beyond that of wet processes. Multiphase dry powder mixing, uniform dispersion of the active material, conductive agent, and binder powders, and initial contact states, are difficult to precisely control and assess. Dynamic fiberization process: The generation, length, orientation, distribution density and the three-dimensional network topology (overlapping, entanglement, wrapping) of PTFE fibers are highly dependent on process parameters (such as mixing energy input, temperature, and time) and are in dynamic change. Hot pressing densification: Under the action of pressure and temperature, the deformation, slippage, rearrangement of the fiber network and the interfacial bonding state with the active particles / conductive agent directly determine the mechanical strength, pore structure and electrical contact of the electrode. Unfortunately, the existing characterization method system suitable for wet-process electrodes shows systematic deficiencies and missing key information when faced with the unique microstructure formation mechanism of the dry process (especially the fiberization process): failure to evaluate the uniformity of powder mixing, lack of characterization of the degree of fiberization and network structure (core pain point), and fuzzy mapping relationship between electrode microstructure and performance. For example, the rheological test (viscosity, thixotropy) of traditional wet-process slurry can directly reflect the dispersion state, but there is a lack of effective in-situ and online rapid evaluation methods after dry-process powder mixing. Existing offline methods (such as SEM / EDS point scanning) have poor sampling representativeness, are time-consuming, have difficulty capturing local heterogeneity during dynamic mixing, and cannot determine the film-forming properties of powders after fiberization. Dry electrode technology has become an inevitable option for battery manufacturing upgrades due to its significant advantages. However, the serious lag in current characterization technology, especially the inability to capture the key structural parameters of fiberized powders, has become the biggest bottleneck hindering the technology from moving from the laboratory to large-scale mass production. Scientific research institutions and the industry urgently need to jointly invest in breakthroughs in in-situ, non-destructive, high-throughput, and multi-dimensional characterization technologies, and establish a "structure-process-performance" quantitative relationship map exclusive to dry electrodes. Only in this way can we accurately optimize the process, ensure consistency, release the full potential of dry electrodes, and accelerate the commercialization of the next generation of high-performance batteries. Breaking through the characterization bottleneck is the key to unlocking the future of dry methods. SUMMARY

[0003] The present application discloses a method, system, computer device, storage medium and program product for characterizing the film-forming performance of dry electrode powder after fibrillation, which can quickly determine whether the dry electrode powder can be made into a film, and solves the problem of the lack of detection methods for dry electrode powder.

[0004] The present application is achieved by the following technical solutions:

[0005] The present application first provides a method for characterizing the film-forming performance of dry electrode powder after fibrillation, comprising the following steps:

[0006] S1, mixing the positive or negative material of a lithium / sodium ion battery, a conductive agent and a binder under solvent-free conditions, using a mixing machine to fibrillate to obtain dry electrode powder, and sampling the dry electrode powder to obtain the dry electrode powder to be tested;

[0007] S2, measuring the maximum diffusion diameter A of the bottom surface of the dry electrode powder to be tested and the height B in the vertical direction after the dry electrode powder to be tested is compressed and vibrated, and calculating the film-forming degree W of the dry electrode powder,

[0008]

[0009] wherein K is the ratio of the height and the inner diameter of the container, and the value is 0.6; M is the force applied by the full-automatic small tabletop press to the dry electrode powder to be tested, and S is the area of the applied pressure; F is the vibration frequency of the test equipment, and L is the vibration drop distance of the test equipment;

[0010] S3, determining whether the film-forming degree value W of the dry electrode powder to be tested meets the standard 0.55≤W≤1.2 for making a dry film.

[0011] As a further solution, the method for measuring the maximum diffusion diameter A of the bottom surface of the dry electrode powder to be tested and the height B in the vertical direction after the dry electrode powder to be tested is compressed and vibrated in S2 is:

[0012] S21, keeping the film-forming degree test equipment horizontal;

[0013] S22, placing the dry electrode powder to be tested prepared in step S1 evenly in the container of the test equipment and compressing it to make the powder particles tightly contact each other;

[0014] S23, after scraping off the dry electrode powder that is higher than the conical lower mold of the test equipment and smoothing it, lifting the lower mold gently and starting the test equipment, the vibration frequency F of the test equipment is 0.5-1HZ, the vibration drop distance L is 10-20mm, and the test equipment is jumped for 25 times.

[0015] S24. After the test is completed, use a caliper to measure the maximum diffusion diameter A of the bottom surface of the dry electrode powder and its vertical height B to an accuracy of 1 mm, and the film forming degree W of the dry electrode powder can be calculated.

[0016] As a further solution, the method for tightly compacting the dry electrode powders to be tested in S22 is:

[0017] The dry electrode powder to be tested is quickly loaded into the conical mold of the test equipment in two layers. The first layer is loaded to about 2 / 3 of the height of the conical lower mold of the test equipment. Use a steel ruler to mark it several times in two mutually perpendicular directions. Use a solid stainless steel rod weighing 3 kg and 20 cm long to press it evenly from the edge to the center several times. Then load the second layer and load it to about 20 mm above the conical lower mold. Use a steel ruler to mark it 10 times in each lion direction. Then use a tamping rod to press it evenly 10 times from the edge to the center. Remove the conical upper mold of the test equipment. Finally, use a fully automatic press to apply a force M to the above-mentioned dry electrode powder to be tested. The value range of M is: 25-40 kg, press once, and the time is 5 seconds.

[0018] As a further solution, the method for tightly compacting the dry electrode powders to be tested in S22 is:

[0019] The dry electrode powder to be tested is quickly loaded into the conical mold of the test equipment in two layers. The first layer is loaded to about 2 / 3 of the height of the conical lower mold. The high-frequency vibration of the small vibration platform is used to rearrange the powder particles to improve the density. The powder is then compacted by a press with a pressure range of 3 kg, pressed once, and a time of 3 seconds. The second layer is then loaded to about 20 mm above the conical lower mold. The small vibration platform is started again to rearrange the powder particles and then compacted by a press with a pressure range of 3 kg, pressed once, and a time of 3 seconds. The conical upper mold is removed, and a force M is applied to the above-mentioned dry electrode powder to be tested using a fully automatic press. The value range of M is: 25-40 kg, pressed once, and the time is 5 seconds.

[0020] As a further solution, the method for sampling the dry electrode powder in S1 to obtain the dry electrode powder to be tested is: the circumference of the material tray or material tank is evenly divided into several units, a sample is collected at the position of each unit, and then a sample is collected at the center, and multiple samples are mixed to obtain the dry electrode powder to be tested.

[0021] The present invention also provides a system for characterizing the film-forming performance of powder material after dry-process electrode fibrillation, and the method for characterizing the film-forming performance of powder material after dry-process electrode fibrillation is applied, comprising:

[0022] Material preparation unit, used to prepare dry electrode powder to be tested;

[0023] a data processing unit, which measures the maximum diffusion diameter A of the bottom surface of the dry-process electrode powder to be tested and the height B in the vertical direction thereof after the dry-process electrode powder to be tested is compacted and vibrated, and calculates the filmability W of the dry-process electrode powder;

[0024] a data analysis unit, which determines whether the dry-process electrode film can be made according to the filmability W of the dry-process electrode powder to be tested.

[0025] The application further provides a non-transitory computer readable storage medium, which stores computer instructions, and the computer instructions are executed by a processor to implement the steps of the method for characterizing the film forming performance of the dry-process electrode powder after fibrillation.

[0026] The application further provides a computer device, which comprises a memory and a processor, the processor and the memory are in communication with each other, the memory stores program instructions that can be executed by the processor, and the processor invokes the program instructions to execute the steps of the method for characterizing the film forming performance of the dry-process electrode powder after fibrillation.

[0027] The application further provides a computer program product, which comprises a computer program, and the computer program is executed by a processor to implement the steps of the method for characterizing the film forming performance of the dry-process electrode powder after fibrillation.

[0028] The application has the following characteristics and advantages:

[0029] (1) The application can quickly characterize whether the dry-process electrode powder can be made into a film, and solves the problem that the dry-process electrode detection method is missing and the dry powder material cannot be characterized.

[0030] (2) The test method of the application is simple, easy to implement, widely applicable, and has strong versatility. DETAILED DESCRIPTION

[0031] In order to more clearly illustrate the technical solutions in the embodiments of the application, the following will briefly introduce the drawings needed to be used in the embodiments or prior art description. Obviously, the drawings in the following description are only some embodiments of the application, and other drawings can be obtained by those skilled in the art without creative labor.

[0032] Figure 1 The flowchart of the method for characterizing the film forming performance of the dry-process electrode powder after fibrillation according to the embodiments of the application;

[0033] Figure 2 The schematic diagram of the sampling position according to the embodiments of the application;

[0034] Figure 3Pressing sequence of the tamping rod Figure 1 ;

[0035] Figure 4 Pressing sequence of the tamping rod Figure 2 ;

[0036] Figure 5 Area of the press to apply pressure. DETAILED DESCRIPTION

[0037] In order to facilitate the understanding of the present application, the present application will be described more fully below with reference to the embodiments of the present application, but the scope of the present application is not limited thereby.

[0038] In the description of the present application, it should be understood that the orientation or positional relationship indicated by the terms "center", "longitudinal", "transverse", "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer" and the like is based on the orientation or positional relationship shown in the drawings, and is only for the purpose of facilitating the description of the present application and simplifying the description, and does not indicate or imply that the device or element indicated thereby must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation of the present application. In addition, the terms "first", "second" and the like are only for the purpose of description and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the technical features indicated thereby. Therefore, the features defined with "first", "second" and the like can explicitly or implicitly include one or more of the features. In the description of the present application, the meaning of "a plurality of" is two or more, unless otherwise specified.

[0039] In the description of the present application, it should be noted that, unless otherwise explicitly specified and limited, the terms "mounting", "connecting", "connection" should be understood broadly, for example, it can be fixed connection, or detachable connection, or integrally connected; it can be mechanical connection, or electrical connection; it can be directly connected, or indirectly connected through an intermediate medium, or the communication inside two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0040] A method for characterizing the film-forming performance of dry electrode powder after fibrillation, as shown in Figures 1 to 5 includes the following steps:

[0041] S1, mixing the positive electrode material or negative electrode material, conductive agent and binder of lithium / sodium ion battery under solvent-free condition uniformly, using a mixing machine for fibrillation, to obtain dry electrode powder.

[0042] Preferably, the material of the binder is PTFE, and the material of the conductive agent is at least one of SP and CNTs.

[0043] Preferably, the mixing machine is a homogenizer or a mixing blender.

[0044] Preferably, the preparation of the dry electrode powder is carried out in a tray or a tank, and after obtaining the dry electrode powder, sampling is carried out to obtain the dry electrode powder to be tested.

[0045] The sampling method is as follows: the circumference of the tray or the tank is evenly divided into a plurality of units, and a sample is collected at the position of each unit, and then a sample is collected at the center, and after mixing the plurality of samples, the dry electrode powder to be tested is obtained. During mixing, manual mixing or machine mixing can be used.

[0046] In one or more embodiments, the following steps are performed: Figure 2 In the tank, sampling is carried out at five positions, and 5 samples are simply manually mixed to obtain the dry electrode powder to be tested.

[0047] S2, the dry electrode powder to be tested is quickly characterized by its film-forming degree, and the test method is as follows:

[0048] S21, place the film-forming degree test equipment (test equipment is a cement mortar fluidity tester, model is NLD-3) on a horizontal plane, adjust the height of the four foot pads to ensure that the equipment is horizontal;

[0049] S22, evenly place the dry electrode powder to be tested prepared in step S1 in the container and press tightly to make the powder particles tightly contact each other;

[0050] Specifically, two methods are included:

[0051] The first method is as follows: the dry electrode powder to be tested is quickly loaded into a conical mold in two layers, the first layer is loaded to about 2 / 3 of the height of the conical lower mold, a steel ruler is drawn multiple times in two perpendicular directions, preferably 5 times in each direction; a tamping rod (a solid stainless steel rod with a weight of 3 Kg and a length of 20 cm) is used to press from the edge to the center multiple times, preferably 15 times, then the second layer is loaded, and the second layer is loaded to about 20 mm above the conical lower mold, a steel ruler is drawn 10 times in each direction, and then the tamping rod is used to press from the edge to the center 10 times. The pressing force completely depends on the weight of the tamping rod itself, and the dry electrode powder should be filled in the conical lower mold, and the pressing sequence is shown in Figure 3 and Figure 4 The conical upper mold is removed, and a full-automatic small tabletop press is used to apply a force M to the dry electrode powder to be tested, preferably the value of the applied force is in the range of 25-40 kg, and the pressing is performed once with a time of 5 S, so as to ensure that the powder particles tightly contact each other, as shown in Figure 5(Green represents the area of the press to apply pressure, S = πr 2 = π * 33 * 33 = 3421.2 mm 2 ). When loading the dry electrode powder and pressing, the mold should be held steady with hands and not allowed to move.

[0052] The second method is: the dry electrode powder to be tested is loaded into the conical mold in two layers, the first layer is loaded to about 2 / 3 of the height of the conical lower mold, the powder particles are rearranged by high-frequency vibration of the small vibration platform to reduce the voids and improve the density, and then the press is pressed according to the set pressure, preferably, the pressure value is 3 kg, pressed once, and the time is 3 s; then the second layer is loaded to about 20 mm above the conical lower mold, and the powder particles are rearranged again by starting the small vibration platform, and then the press is pressed according to the set pressure, the pressure value is 3 kg, pressed once, and the time is 3 s. Any press that can achieve the above functions can be used; the conical upper mold is removed, and finally the dry electrode powder to be tested is subjected to force M by using a full-automatic small desktop press, preferably, the force value is 25-40 kg, pressed once, and the time is 5 s, to ensure that the powder particles are in close contact, such as Figure 5 (Green represents the area of the press to apply pressure, S = πr 2 = π * 33 * 33 = 3421.2 mm 2 ). When loading the dry electrode powder and pressing, the mold should be held steady with hands and not allowed to move.

[0053] S23, after pressing, the dry electrode powder above the conical lower mold is scraped off and smoothed, the lower mold is gently lifted, and then the equipment is started, the equipment parameters are vibration frequency F (0.5-1 HZ) and vibration drop distance L (10-20 mm), and 25 times of jumping is performed. The whole test should be completed within 5-6 min.

[0054] Preferably, the method for scraping off and smoothing the dry electrode powder above the conical lower mold is: the dry electrode powder above the conical lower mold is scraped off and smoothed twice from the middle to the edge by using a steel ruler, and the dry electrode powder falling on the desktop is wiped off.

[0055] S24, after the test, the maximum spreading diameter A of the bottom surface of the dry electrode powder and the height B in the vertical direction thereof are measured by using a caliper, accurate to 1 mm, and the filmability W of the dry electrode powder can be calculated.

[0056]

[0057] Wherein, K = H / R1 = 0.6, H is the height of the conical lower mold 60mm, R1 is the inner diameter of the bottom 100mm, R2 is the inner diameter of the top 70mm; M is the force applied by the full-automatic small bench press to the dry electrode powder, S is the area of the applied pressure; F is the vibration frequency of the test equipment, L is the vibration drop distance of the test equipment;

[0058] The film-forming degree value W formula characterizes the ability of the dry electrode powder to aggregate into a film under a specific mechanical action, i.e., a specific pressure and vibration action, which can indirectly characterize the bonding performance of the fibrillated dry electrode powder. A higher film-forming degree value indicates that the fiber network formed by the fibrillation of the lithium / sodium ion battery positive material or negative material, conductive agent and binder after uniform mixing under solvent-free conditions has good film-forming properties. Fibrillation significantly enhances the inter-particle bonding force through van der Waals forces and mechanical anchoring, giving the dry film high self-supporting properties. Fibrillation enables the powder to change from a loose packed state to a viscoelastic continuum.

[0059] Wherein, the ratio of the height B of the dry electrode powder to be tested in the vertical direction after compaction and vibration to the maximum spread diameter A directly reflects the aggregation and spreading ability of the dry electrode powder. When the ratio of the height B to the diameter A is relatively high, the powder tends to be in an aggregated state rather than a dispersed particle state after the full-automatic small bench press is used to compact and vibrate the dry electrode powder to be tested, and the powder can form better aggregation in the form of a continuum. At this time, the powder does not form an excessively aggregated film that cannot be spread due to high aggregation, nor does it form a film due to excessive looseness. This indicates that the lithium / sodium ion battery positive material or negative material, conductive agent and binder after uniform mixing under solvent-free conditions are well fibrillated, which makes it easier to form a state of relatively aggregated powder and moderate spreading, indicating better film-forming ability. In addition, K reflects the shape of the container. Since the height-to-diameter ratio affects the powder's packing state and flow behavior after being subjected to stress, K is a correction factor for the influence of the container shape on the powder. The ratio of M / S represents the pressure applied by the full-automatic small bench press to the dry electrode powder to be tested. By taking the pressure as a parameter in the film-forming degree, the influence of different test conditions on the test results can be balanced. The ratio of the test equipment vibration drop distance L to the test equipment vibration frequency F reflects the vibration intensity of the test equipment, which is a key basic physical quantity for characterizing the vibration intensity or energy level input by the test equipment to the powder, for quantifying the influence of vibration on the final powder morphology, correcting the influence of vibration energy on the aggregation and dispersion behavior of the powder, and improving the accuracy of the test results.

[0060] S3, determining whether the film-forming degree value of the dry electrode powder meets the standard for making a dry film; the standard is that when the film-forming degree W of the dry electrode powder satisfies 0.55 ≤ W ≤ 1.2, the dry electrode powder can be made into a dry film.

[0061] Example 1

[0062] (1) The graphite negative electrode material, conductive agent SP, and binder PTFE were mixed in a mass ratio of 93:2:5 under solvent-free conditions using a dry mixing stirrer at 2000 rpm for 5 min, and high-speed shearing fibrillation at 5000 rpm for 8 min to form a dry electrode negative dry powder.

[0063] (2) The above negative dry powder was tested according to the test procedure in step S2, with the following parameters:

[0064] The dry electrode powder was pressed once by a full-automatic small bench press with a force M = 30 kg for 5 s;

[0065] The test equipment parameters were vibration frequency F = 1 HZ and vibration drop distance L = 10 mm ± 0.1 mm;

[0066] After the test, the maximum spread diameter A = 110 mm and the vertical height B = 55 mm of the dry powder were measured with a caliper, and the film formation degree W = 0.73 was calculated.

[0067] (3) The value of the film formation degree 0.73 was within the standard range 0.55 ≤ W ≤ 1.2 in step S3, indicating that the dry powder could theoretically be made into a dry film;

[0068] (4) The above dry powder was pressed into a film using a film forming machine with the following parameters: heating roller temperature 100°C, roller gap 0.06 mm, and pressure 5T. It was found that the dry powder could indeed be made into a dry film.

[0069] Example 2

[0070] The difference between this embodiment and Example 1 is the proportion of the graphite negative electrode mixture formula, and the rest of the procedures are the same.

[0071] (1) The graphite negative electrode material, conductive agent SP, conductive agent CNTs, and binder PTFE were mixed in a mass ratio of 94:2:1:3 under solvent-free conditions using a dry mixing stirrer at 2000 rpm for 5 min, and high-speed shearing fibrillation at 5000 rpm for 8 min to form a dry electrode negative dry powder.

[0072] (2) The above negative dry powder was tested according to the test procedure in step S2, with the following parameters:

[0073] The dry electrode powder was pressed once by a full-automatic small bench press with a force M = 30 kg for 5 s;

[0074] The test equipment parameters were vibration frequency F = 1 HZ and vibration drop distance L = 10 mm ± 0.1 mm;

[0075] After completion, the maximum diffusion diameter of the bottom surface of the dry powder was measured with a caliper, A = 115 mm, and the vertical height B = 50 mm. Calculation showed that the film forming degree W = 0.63.

[0076] (3) The film forming degree value of 0.63 is within the standard range of 0.55≤W≤1.2 in step S3, indicating that the dry powder can theoretically be made into a dry film;

[0077] (4) The dry powder was pressed into a film using a film forming machine. The parameters were set as the heating roller temperature of 100°C, the roller gap of 0.06mm, and the pressure of 5T. It was found that the dry powder could indeed be made into a dry film.

[0078] Example 3

[0079] The difference between this embodiment and embodiment 1 is that a fully automatic small desktop press applies force M to the dry electrode powder, and the rest of the processes are the same.

[0080] (1) The graphite negative electrode material, conductive agent SP, and binder PTFE were mixed in a mass ratio of 93:2:5, mixed evenly in a dry mixing mixer at 2000 rpm for 5 min under solvent-free conditions, and high-speed shear fibrillation was performed at 5000 rpm for 8 min to form a dry electrode negative electrode dry powder.

[0081] (2) The above-mentioned negative electrode dry powder is tested according to the test steps in step S2, wherein the parameters are as follows:

[0082] A fully automatic small table press applies a force of M = 40 kg to the dry electrode powder, pressing once for 5 seconds;

[0083] Test equipment parameters: vibration frequency F = 1HZ, vibration drop distance L = 10mm ± 0.1mm;

[0084] After completion, the maximum diffusion diameter of the bottom surface of the dry powder was measured with a caliper, A = 105 mm, and the vertical height B = 57 mm. Calculation showed that the film forming degree W = 1.06.

[0085] (3) The film forming degree value of 1.06 is within the standard range of 0.55≤W≤1.2 in step S3, indicating that the dry powder can theoretically be made into a dry film;

[0086] (4) The dry powder was pressed into a film using a film forming machine. The parameters were set as the heating roller temperature of 100°C, the roller gap of 0.06mm, and the pressure of 5T. It was found that the dry powder could indeed be made into a dry film.

[0087] Example 4

[0088] The difference between this embodiment and embodiment 1 is that the device vibration drop distance L is tested, and the rest is the same as the process.

[0089] (1) The graphite negative electrode material, conductive agent SP, and binder PTFE are mixed in a mass ratio of 93:2:5 under solvent-free conditions using a dry mixing stirrer to mix uniformly at 2000 rpm for 5 min, and high-speed shearing fibrillation at 5000 rpm for 8 min to form a dry electrode negative dry powder.

[0090] (2) The above negative dry powder is tested according to the test steps in step S2, and the parameters are as follows:

[0091] The dry electrode powder is pressed once by a full-automatic small desktop press with a force M = 30 kg, and the time is 5 s;

[0092] The test equipment parameters are vibration frequency F = 1 HZ and vibration drop distance L = 20 mm ± 0.1 mm;

[0093] After the end, the maximum diffusion diameter A = 150 mm of the dry powder bottom surface is measured by a caliper, and the height B = 38 mm in the vertical direction is calculated, and the film forming degree W = 0.74 is calculated.

[0094] (3) The value of the film forming degree 0.74 is within the range of 0.55≤W≤1.2 in step S3, which indicates that the dry powder can theoretically be made into a dry film;

[0095] (4) The above dry powder is pressed into a film using a film forming machine, and the parameters are set as follows: heating roller temperature 100℃, roller gap 0.06mm, pressure 5T, and it is found that the dry powder can indeed be made into a dry film.

[0096] Example 5

[0097] The difference between this embodiment and embodiment 1 is the proportion of the graphite negative electrode mixture formula, and the rest is the same as the process.

[0098] (1) The graphite negative electrode material, conductive agent SP, and binder PTFE are mixed in a mass ratio of 97.5:2:0.5 under solvent-free conditions using a dry mixing stirrer to mix uniformly at 2000 rpm for 5 min, and high-speed shearing fibrillation at 5000 rpm for 8 min to form a dry electrode negative dry powder.

[0099] (2) The above negative dry powder is tested according to the test steps in step S2, and the parameters are as follows:

[0100] The dry electrode powder is pressed once by a full-automatic small desktop press with a force M = 30 kg, and the time is 5 s;

[0101] Test equipment parameters vibration frequency F = 1HZ, vibration drop distance L = 10mm ± 0.1mm;

[0102] After the end, the maximum diffusion diameter A = 160mm of the dry powder bottom surface is measured by the caliper, the height B = 30mm in the vertical direction, and the film forming degree W = 0.27 is calculated.

[0103] (3) The value of the film forming degree 0.27 is not in the standard range 0.55≤W≤1.2 of step S3, which indicates that the dry powder cannot be made into a dry film sheet in theory;

[0104] (4) The dry powder is pressed and formed by using a film forming machine, the heating roller temperature is set to 100℃, the roller gap is 0.06mm, and the pressure is 5T, and it is found that the dry powder cannot be made into a dry film sheet.

[0105] Comparative Example

[0106] The difference between the comparative example and example 1 is the proportion of the graphite negative electrode mixture formula, and the rest is the same.

[0107] (1) The graphite negative electrode material, conductive agent SP, and binder PTFE are mixed in a mass ratio of 98:2:0 by using a dry mixing stirrer under solvent-free conditions, 2000rpm for 5min, and high-speed shearing fibrillation 5000rpm for 8min, to form a dry electrode negative powder.

[0108] (2) The above negative dry powder is tested according to the test steps in step S2, and the parameters are as follows:

[0109] The dry electrode powder is pressed by a full-automatic small-sized bench press once, and the time is 5S;

[0110] Test equipment parameters vibration frequency F = 1HZ, vibration drop distance L = 10mm ± 0.1mm;

[0111] After the end, the maximum diffusion diameter A = 200mm of the dry powder bottom surface is measured by the caliper, the height B = 10mm in the vertical direction, and the film forming degree W = 0.07 is calculated.

[0112] (3) The value of the film forming degree 0.07 is in the standard range 0.55≤W≤1.2 of step S3, which indicates that the dry powder cannot be made into a dry film sheet in theory;

[0113] (4) The dry powder is pressed and formed by using a film forming machine, the heating roller temperature is set to 100℃, the roller gap is 0.06mm, and the pressure is 5T, and it is found that the dry powder cannot be made into a dry film sheet.

[0114] The results of the quick characterization test method for the dry powder in the examples, comparative examples are as follows table 1.

[0115] Table 1

[0116]

[0117]

[0118] The method for characterizing the film forming performance of the dry powder after the original fiberization of the dry method electrode provided by the application can quickly characterize whether the dry method electrode powder can be made into a film sheet, and solves the problems of the lack of detection methods for the dry method electrode and the inability to characterize the dry powder material.

[0119] The application further provides a system for characterizing the film forming performance of the dry powder after the original fiberization of the dry method electrode, comprising

[0120] A material preparation unit is used to prepare dry powder material of the negative electrode of the dry method electrode;

[0121] A data processing unit measures the maximum diffusion diameter A of the bottom surface of the dry method electrode powder and the height B in the vertical direction after the dry method electrode negative dry powder material is compressed and vibrated, and calculates the filmability W of the dry method electrode powder;

[0122] A data analysis unit determines whether the dry method electrode powder can be made into a dry method film sheet according to the filmability W of the dry method electrode powder.

[0123] The system can quickly characterize whether the dry method electrode powder can be made into a film sheet, and solves the problems of the lack of detection methods for the dry method electrode and the inability to characterize the dry powder material.

[0124] The application further provides a non-transitory computer readable storage medium, which stores computer instructions, and the computer instructions are executed by a processor to implement the method for characterizing the film forming performance of the dry powder after the original fiberization of the dry method electrode.

[0125] The application further provides a computer device, which comprises a memory and a processor, the processor and the memory are in communication with each other, the memory stores program instructions that can be executed by the processor, and the processor calls the program instructions to execute the method for characterizing the film forming performance of the dry powder after the original fiberization of the dry method electrode.

[0126] The application further provides an electronic device, which comprises a processor, a memory and a computer program; wherein the processor is connected with the memory, the computer program is stored in the memory, and when the electronic device is running, the processor executes the computer program stored in the memory, so that the electronic device executes the instructions for implementing the method for characterizing the film forming performance of the dry powder after the original fiberization of the dry method electrode.

[0127] It should be noted that the above-mentioned embodiments illustrate rather than limit the application, and that those skilled in the art will be able to design many alternative embodiments without departing from the scope of the application. Accordingly, the legal scope of the application is defined only by the appended claims.

Claims

1. A method for characterizing the film-forming properties of dry-process electrode powder after fibrillation, characterized in that: The process includes the following steps: S1. Mixing the positive electrode material or negative electrode material of a lithium / sodium ion battery, a conductive agent, and a binder in a solvent-free condition and then fibrillating the mixture to obtain a dry electrode powder. Sampling the dry electrode powder to obtain a dry electrode powder to be tested; S2. After compacting and vibrating the dry electrode powder to be tested, measure the maximum diffusion diameter A of the bottom surface of the dry electrode powder to be tested and its vertical height B, and calculate the film forming degree W of the dry electrode powder. Wherein, K is the ratio of the container height to the inner diameter, which is set to 0.6; M is the force applied by the fully automatic small desktop press to the dry electrode powder to be tested, S is the area where the pressure is applied; F is the vibration frequency of the test equipment, and L is the vibration drop distance of the test equipment; S3. Determine whether the film-forming property value W of the dry-process electrode powder to be tested meets the standard of being able to be made into a dry-process membrane: 0.55≤W≤1.

2.

2. The method for characterizing the film-forming properties of dry-process electrode powder after fibrillation according to claim 1, characterized in that: The method for measuring the maximum diffusion diameter A of the bottom surface of the dry electrode powder to be tested and its vertical height B after the dry electrode powder to be tested is compacted and vibrated in S2 is: S21. Keep the film-forming degree test equipment level; S22, evenly placing the dry electrode powder to be tested prepared in step S1 in a container of the testing equipment and pressing it tightly so that the powder particles are in close contact with each other; S23. Scrape and smooth the dry electrode powder that protrudes from the conical lower mold in the test equipment, gently lift the lower mold, and start the test equipment. The test equipment vibrates at a frequency F of 0.5 to 1 Hz and a drop distance L of 10 to 20 mm for 25 beats. S24. After the test is completed, use a caliper to measure the maximum diffusion diameter A of the bottom surface of the dry electrode powder and its vertical height B to an accuracy of 1 mm, and the film forming degree W of the dry electrode powder can be calculated.

3. The method for characterizing the film-forming properties of dry-process electrode powder after fibrillation according to claim 2, characterized in that: The method for tightly compacting the dry electrode powders to be tested in S22 is: The dry electrode powder to be tested is quickly loaded into the conical mold of the test equipment in two layers. The first layer is loaded to about 2 / 3 of the height of the conical lower mold of the test equipment. Use a steel ruler to mark it several times in two mutually perpendicular directions. Use a solid stainless steel rod weighing 3 kg and 20 cm long to press it evenly from the edge to the center several times. Then load the second layer and load it to about 20 mm above the conical lower mold. Use a steel ruler to mark it 10 times in each lion direction. Then use a tamping rod to press it evenly 10 times from the edge to the center. Remove the conical upper mold of the test equipment. Finally, use a fully automatic press to apply a force M to the above-mentioned dry electrode powder to be tested. The value range of M is: 25-40 kg, press once, and the time is 5 seconds.

4. The method for characterizing the film-forming properties of dry-process electrode powder after fibrillation according to claim 2, characterized in that: The method for tightly compacting the dry electrode powders to be tested in S22 is: The dry electrode powder to be tested is quickly loaded into the conical mold of the test equipment in two layers. The first layer is loaded to about 2 / 3 of the height of the conical lower mold. The high-frequency vibration of the small vibration platform is used to rearrange the powder particles to improve the density. The powder is then compacted by a press with a pressure range of 3 kg, pressed once, and a time of 3 seconds. The second layer is then loaded to about 20 mm above the conical lower mold. The small vibration platform is started again to rearrange the powder particles and then compacted by a press with a pressure range of 3 kg, pressed once, and a time of 3 seconds. The conical upper mold is removed, and a force M is applied to the above-mentioned dry electrode powder to be tested using a fully automatic press. The value range of M is: 25-40 kg, pressed once, and the time is 5 seconds.

5. The method for characterizing the film-forming properties of dry-process electrode powder after fibrillation according to claim 1, characterized in that: The method for sampling the dry electrode powder in S1 to obtain the dry electrode powder to be tested is: evenly divide the circumference of the material tray or material tank into several units, collect a sample at the position of each unit, and then collect a sample at the center, and mix the multiple samples to obtain the dry electrode powder to be tested.

6. The method for characterizing the film-forming properties of dry-process electrode powder after fibrillation according to claim 1, characterized in that: The material of the binder is PTFE, and the material of the conductive agent is at least one of SP and CNTs.

7. A system for characterizing the film-forming properties of a dry-process electrode powder after fibrillation, using the method for characterizing the film-forming properties of a dry-process electrode powder after fibrillation according to any one of claims 1 to 6, characterized in that: include Material preparation unit, used to prepare dry electrode powder to be tested; The data processing unit measures the maximum diffusion diameter A of the bottom surface of the dry electrode powder to be tested and its vertical height B after compacting and vibrating the dry electrode powder to be tested, and calculates the film forming degree W of the dry electrode powder; The data analysis unit determines whether the dry-process electrode powder can be made into a dry-process membrane according to the film-forming degree W of the dry-process electrode powder to be tested.

8. A computer device comprising a memory and a processor, wherein the memory stores a computer program, wherein: When the processor executes the computer program, the steps of the method according to any one of claims 1 to 6 are implemented.

9. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the steps of the method according to any one of claims 1 to 6 are implemented.

10. A computer program product comprising a computer program, characterized in that When the computer program is executed by a processor, the steps of the method according to any one of claims 1 to 6 are implemented.

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