Method for evaluating fibrosis degree of dry-method battery mixed material

Abstract

The invention belongs to the technical field of battery material fibration degree evaluation, and relates to a dry method battery mixed material fibration degree evaluation method, which comprises the following steps: S1, detecting resistance generated by the flowing of a fibration mixed material; and S2, analyzing the maximum resistance according to the resistance, and evaluating the fibrosis degree of the mixed material according to the maximum resistance. According to the technical scheme, the consistency of the fibration degrees of the same batch of materials with the same fibration condition can be evaluated, and the fibration degrees of the same batch of materials with different fibration conditions can also be evaluated.

Description

Technical Field

[0001] This invention relates to the field of battery material fiberization degree assessment technology, and in particular to a method for assessing the fiberization degree of dry-process battery mixtures. Background Technology

[0002] Currently, the preparation of positive and negative electrodes or solid electrolytes in batteries includes wet coating and dry preparation. While the wet coating process has been continuously optimized and the technology and equipment have reached a very mature stage, it undeniably requires cumbersome processes such as drying and solvent recovery after wet coating. Equipment for processes like binder preparation, slurry coating, electrode baking, and NMP solvent recovery is large in area, costly, and requires significant maintenance and manpower. Existing dry preparation technology uses fibrous binders to bond battery materials, enabling the powder materials to form a self-supporting film. The dry film preparation process eliminates the need for NMP solvent, simplifying the electrode preparation process, reducing production costs, and making the production process more environmentally friendly.

[0003] In dry film-forming processes, the degree of fiberization of the binder is a crucial factor affecting the process itself. However, existing methods for characterizing the degree of binder fiberization are inadequate, lacking effective technical means to monitor it, making them unsuitable for mass production quality control. Therefore, how to quantitatively assess the degree of binder fiberization to optimize process parameters and improve product quality is a problem urgently needing to be solved by those skilled in the art. Summary of the Invention

[0004] To address the aforementioned problems, this invention discloses a method for evaluating the degree of fibrousness in dry-process battery mixtures. The technical solution of this invention is implemented as follows:

[0005] This invention discloses a method for evaluating the degree of fibrosis in dry-process battery mixtures, the method comprising the following steps:

[0006] S1. Detect the resistance generated by the flow of the fiberized mixture;

[0007] S2. Analyze the maximum resistance based on the resistance, and evaluate the degree of fiberization of the mixture based on the maximum resistance.

[0008] Furthermore, the mixture includes battery materials and a fiberizable binder.

[0009] Furthermore, step S1 includes:

[0010] S11. The fiberized mixture is fed into the torque detection device;

[0011] S12. The torque detection device stirs the mixture and detects the resistance to the flow of the mixture.

[0012] Furthermore, the torque detection device includes a mixture receiving unit, a mixture shearing unit, a driving unit, and a sensing unit.

[0013] Step S11 includes feeding the mixture into the mixture receiving unit;

[0014] Step S12 includes a drive unit on the outside of the mixture receiving unit driving the mixture shearing unit inside the mixture receiving unit to rotate, stirring the mixture, and a sensing unit on the mixture shearing unit detecting the torque value; the rotational speed R of the drive unit is in the range of R≤25r / s;

[0015] The torque value reflects the resistance generated by the flow of the mixture.

[0016] Furthermore, step S12 also includes applying a constant pressure, F ≤ 50 N, to the mixture in the mixture receiving unit by the pressure unit in the torque detection device.

[0017] Furthermore, step S12 also includes regulating the constant temperature inside the mixture container unit by the temperature control unit in the torque detection device, wherein the temperature T is in the range of 20℃≤T≤120℃.

[0018] Furthermore, step S2 includes,

[0019] S21. Filter the acquired torque value to obtain a preprocessed value;

[0020] S22. Determine the maximum torque value based on the preprocessed value and terminate the acquisition of torque value.

[0021] Furthermore, step S22 includes:

[0022] The test is terminated when several consecutive preprocessed values ​​obtained exceed a preset unit value relative to the maximum preprocessed value.

[0023] Furthermore, multiple samples are taken from the same batch of mixed materials, and the samples are used as the maximum resistance test for the mixed materials. The difference between the maximum resistance of different samples is compared. If the difference is within a preset difference range, it indicates that the batch of mixed materials is uniformly fiberized. The preset difference range D is ±2%.

[0024] Furthermore, the degree of fiberization is evaluated for multiple batches of mixtures with different fiberization processes, and the best fiberization process is obtained based on the maximum resistance of the mixture.

[0025] The advantages of this invention are as follows:

[0026] When evaluating the same batch of materials with different fiberization conditions using the technical solution of this invention, the process parameters of the fiberization process can be optimized. That is, among the same batch of materials with different fiberization conditions, the greater the maximum torque value of the material under which fiberization condition, the better the degree of fiberization of the material under that fiberization condition.

[0027] Different fiberization conditions can be further divided into different fiberization methods, and the same fiberization method but different specific conditions such as rotation speed and time. These conditions can be used to determine which fiberization conditions are the optimal parameters for this batch of materials.

[0028] In addition, when evaluating the same batch of materials with the same fiberization conditions using the technical solution of the present invention, the consistency of the degree of fiberization of the same batch of materials can be evaluated. That is, if the difference in the maximum torque value of the same batch of materials with the same fiberization conditions is within the range of ≤±2%, it is considered that the consistency of the degree of fiberization of the batch of materials is good.

[0029] Here, "the same batch of materials" refers to materials with the same composition and content, and may also include materials from the same raw material supplier. This can be used to test whether the degree of fiberization of the batch of materials meets production requirements. Attached Figure Description

[0030] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only one embodiment of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0031] Figure 1 This is a structural diagram of the evaluation device used in the embodiments of the present invention;

[0032] Figure 2 for Figure 1 Enlarged view of a portion of the structure in the evaluation device shown;

[0033] Figure 3 This is a cross-sectional view of the evaluation device used in the embodiments of the present invention;

[0034] Figure 4 for Figure 3 Enlarged view of a portion of the structure shown in the cross-sectional diagram;

[0035] Figure 5 Time-torque curves for materials in group A, group B, and group C;

[0036] Figure 6 Time-torque curves for materials in groups D, E, and F.

[0037] The symbols in the above figures have the following meanings:

[0038] 1. Material receiving unit;

[0039] 2. Feed inlet;

[0040] 3. Pressure bar;

[0041] 4. Rotor. Detailed Implementation

[0042] The technical solutions of the present invention will now be clearly and completely described with reference to the embodiments and accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0043] The dry-process battery mixture used in this application to evaluate the degree of fibrosis includes battery materials and a fibrous binder. The dry-process battery mixture is prepared by mixing the battery materials and the fibrous binder in a mixer.

[0044] In specific applications, battery materials can be positive electrode materials, negative electrode materials, or electrolyte materials.

[0045] When the battery material is a positive electrode material, the positive electrode material includes the positive electrode active material.

[0046] The positive electrode active material may be any positive electrode active material known in the art for use in batteries. As an example, the positive electrode active material may include at least one of the following materials: lithium-containing phosphates with an olivine structure, lithium transition metal oxides, and their respective modified compounds. However, this application is not limited to these materials, and other conventional materials that can be used as positive electrode active materials for batteries may also be used.

[0047] When the battery material is a negative electrode material, the negative electrode material includes the negative electrode active material.

[0048] The specific types of anode active materials are not limited and can be selected according to requirements. Specifically, anode active materials are selected from natural graphite, artificial graphite, mesophase microcarbon spheres (MCMB), hard carbon, soft carbon, silicon, silicon-carbon composites, Li-Sn alloys, Li-Sn-O alloys, Sn, SnO, SnO2, and spinel-structured lithiated TiO2-Li4Ti5O. 12 One or more of Li-Al alloys. Non-limiting examples of carbon materials include crystalline carbon, amorphous carbon, and mixtures thereof. Crystalline carbon can be amorphous or flake-shaped, small flake-shaped, spherical, or fibrous natural or artificial graphite. Amorphous carbon can be soft carbon, hard carbon, mesophase pitch carbides, calcined coke, etc.

[0049] For example, fiberizable adhesives include, but are not limited to, polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), polyacrylic acid (PAA), styrene-butadiene rubber (SBR), cellulose, nanocellulose, nanofibers (CNF), polyaniline (PANI), polypyrrole (PPy), polyrotaxane, and any combination thereof.

[0050] The degree of dispersion of the dry-process battery mixture is crucial when forming the dry electrode film. The degree of dispersion of the battery materials and the degree of fiberization of the binder have a significant impact on the self-support of the dry electrode film. In the dry electrode film, uneven dispersion of the electrode materials and binder can also affect the cell performance. Therefore, to obtain a dry electrode film that meets quality standards, it is necessary to evaluate the degree of dispersion and fiberization of the binder in the dry-process battery mixture.

[0051] It should be noted that the "fibrillation" referred to in this invention refers to feeding materials into high-speed, high-shear equipment, where high-intensity mechanical shearing or tensile forces, such as high-speed stirring, rolling, and ball milling, cause the binder (such as PTFE molecules) chains to break and rearrange into a fibrous structure. The high-speed, high-shear equipment includes air jet mills, twin-screw extruders, mixers, and differential roller presses.

[0052] Because existing methods for characterizing the degree of fiberization in adhesives are imperfect and lack effective technical means to monitor the degree of fiberization in adhesives, they are not suitable for mass production quality monitoring.

[0053] To address the aforementioned issues, this application proposes a method for evaluating the degree of fibrousness in dry-process battery materials.

[0054] The technical solution of this application will be described in detail below through embodiments.

[0055] In one specific embodiment, a method for evaluating the degree of fibrousness of dry-process battery mixtures employs, as follows: Figures 1-4 The evaluation device shown.

[0056] The evaluation device includes a material receiving unit, a material shearing unit, a drive unit, a sensing unit, a control unit, a feeding unit, a pressure unit, and a temperature control unit.

[0057] The material receiving unit has an opening at the top and is used to hold the fiberized mixture.

[0058] A material shearing unit is disposed within a material receiving unit. In this embodiment, the material shearing unit includes a pair of rotors 4, the surfaces of which are provided with spiral protrusions to promote the flow and dispersion of the mixture.

[0059] A drive unit is disposed outside the material receiving unit, and its output shaft extends into the material receiving unit and is connected to the material shearing unit for driving the material shearing unit to rotate. In this embodiment, the drive unit includes a motor, which is fixed outside the material receiving unit. The output end of the motor extends into the material receiving unit and is connected to the material shearing unit for driving the material shearing unit to rotate, thereby stirring the mixture inside the material receiving unit.

[0060] A sensing unit, connected between the drive unit and the material shearing unit, is used to measure the resistance generated during material flow. In this embodiment, the sensing unit is a torque sensor, and the torque value of the torque sensor is the "counter-resistance torque" experienced by the rotor 4 when it rotates. This torque value reflects the resistance generated by the flow of the mixed material.

[0061] The control unit, sensing unit, and drive unit are all communicatively connected. The control unit is a conventional intelligent device control hub or control box, used to control the operation of various components of the device. As it is a common device in this field, it will not be described in detail here.

[0062] The feeding unit is connected to the opening of the material receiving unit, which facilitates feeding materials into the material receiving unit.

[0063] The pressure unit, located above the feeding unit, facilitates pressing materials into the material receiving unit and prevents the mixture from overflowing during the mixing process in the material shearing unit, thus maintaining material consistency. Specifically, the pressure unit is a vertically movable pressure rod 3. One end of the pressure rod extends into the material receiving unit to press the mixture into it and seals the opening of the material receiving unit, preventing the mixture from overflowing during mixing.

[0064] The temperature control unit adjusts the temperature inside the material receiving unit to maintain a constant temperature.

[0065] This invention provides a method for evaluating the fibrous nature of dry-process battery materials, the evaluation method comprising the following steps:

[0066] S1. Detect the resistance generated by the flow of the fiberized mixture.

[0067] The fibrous mixture refers to the mixture formed by mixing a fibrous binder with battery materials (positive electrode material, negative electrode material, or electrolyte material) until the binder becomes fibrous. The process of binder fibrosis is the transformation of the binder from discrete particles or short fibers into a continuous, interwoven fiber network. The higher the degree of fibrosis, the denser the fiber network, the more cross-linking points in the mixture, and the stronger the adsorption force and the tighter the entanglement between the fibrous binder and the battery material. This results in greater resistance to the flow of the mixture. Therefore, the degree of fibrosis of the mixture can be determined by detecting the resistance generated during flow.

[0068] In step S1, detecting the resistance generated by the flow of the fiberized mixture specifically includes the following steps:

[0069] S11. The fiberized mixture is fed into the torque detection device.

[0070] S12. The torque detection device stirs the mixture and detects the resistance to the flow of the mixture.

[0071] The fiberized mixture is fed into a torque detection device, which stirs the mixture to make it flow, and the resistance to the flow of the mixture is detected.

[0072] Specifically, the mixture is fed into the mixture receiving unit of the torque detection device. The drive unit on the outside of the mixture receiving unit drives the mixture shearing unit inside the mixture receiving unit to rotate, thereby stirring the mixture. The torque value is detected by the sensing unit (torque sensor) set on the mixture shearing unit. The torque value detected by the sensing unit reflects the resistance generated by the flow of the mixture.

[0073] When the rotor of the torque detection device rotates and stirs the mixture, the mixture exerts a counterforce (a torque that opposes the rotation of the blades) on the rotating rotor. The greater the resistance, the stronger the counterforce; the two are strictly positively correlated. During the stirring process, the torque sensor detects the counterforce acting on the rotor. This counterforce reflects the resistance to the flow of the mixture, thus helping to determine the degree of fiberization.

[0074] The rotational speed R of the drive unit is within the range of R ≤ 25 r / s. If the stirring speed > 25 r / s (high-speed stirring), the stirring blades will further affect the mixture, potentially promoting further fiberization or causing fiber breakage and separation of interlacing points. Stirring speeds exceeding this range damage the fiber network formed by the originally well-fiberized mixture. In this case, the detected resistance is the flow resistance of the damaged mixture, not the resistance corresponding to the original degree of fiberization, directly leading to misjudgments of the fiberization level in the test results. Within this stirring speed range, the force exerted by the stirring blades on the material is gentle and will not affect the original fiber network of the mixture. The detected resistance accurately reflects the mechanical obstruction and dragging force caused by the interlacing of binder and battery material fibers, ensuring a strong correlation between the test results and the actual degree of fiberization.

[0075] While the rotor of the torsion detection device is stirring the mixture, a constant pressure is also applied to the mixture in the mixture receiving unit through a pressure unit (pressure rod). This helps to ensure contact between the material and the stirring rotor during the stirring process, preventing the rotor from spinning idly and affecting the detection results of the torque sensor.

[0076] The applied constant pressure F ≤ 50N. Setting the constant pressure within this range helps to avoid damage to the material caused by excessive pressure, and prevents excessive pressure from placing an excessive load on the rotor rotation, thus affecting the service life of the equipment.

[0077] While the rotor of the torque detection device agitates the mixture, the temperature control unit within the torque detection device also regulates the temperature within the mixture receiving unit to maintain a constant temperature. By setting a constant temperature, it helps eliminate the interference of temperature fluctuations on the quantitative relationship between "degree of fibrousness" and "flow resistance," ensuring the accuracy of torque detection.

[0078] The temperature range T is 20℃ ≤ T ≤ 120℃. Limiting the mixing temperature within this range helps ensure smooth mixing and testing. Excessively high temperatures can lead to fiber degradation, oxidation, or damage to material properties; excessively low temperatures can cause fiber breakage and material caking. This setting within the specified temperature range helps avoid the adverse effects of extreme temperatures on the mixture.

[0079] S2. Analyze the maximum resistance based on the resistance analysis, and assess the degree of fiberization of the mixture based on the maximum resistance.

[0080] Specifically, the resistance generated by the flow of the mixture is obtained; the maximum resistance generated by the flow of the mixture is analyzed based on the resistance generated by the flow, and the mixture is evaluated based on the maximum resistance.

[0081] Reference Figure 5 , Figure 5This graph displays the relationship between torque values ​​and time obtained from mixing different materials. It reflects the resistance generated during the flow of the mixture. Figure 5 As can be seen, the torque value initially increases and then decreases with the stirring of the mixture. When stirring is initiated, the material is in a static or insufficiently flowing state. Material around the rotor is gradually drawn into the flow region, increasing the volume of material involved in the stirring and causing the stirring resistance to gradually rise. As the material gradually transitions from localized flow to overall circulating flow, the flow resistance distribution becomes more uniform, the system reaches dynamic equilibrium, and the torque tends to stabilize or slightly decrease. The peak torque directly reflects the minimum destructive force required to agitate the mixture. The better the degree of fiberization in the mixture, the greater the minimum destructive force required, and the higher the peak torque. Therefore, the degree of fiberization of the mixture can be effectively assessed through the maximum resistance.

[0082] In step S2, the maximum resistance is analyzed based on the resistance, and the degree of fiberization of the mixture is evaluated based on the maximum resistance. This specifically includes the following steps:

[0083] S21. When obtaining the resistance generated by the mixture, the torque value of the rotor is obtained by the torque sensor according to the preset time, and the torque value is smoothed and filtered to obtain the preprocessed value, so as to avoid a large number of meaningless local extreme points due to small fluctuations.

[0084] Specifically, a smoothing window is set up, with an example, but not limited, window size of 5. Five consecutive torque values ​​are retained within the window. Each acquired torque value is added to the window, and one torque value is removed from the window. The average of the torque values ​​within the window is calculated to perform smoothing filtering preprocessing. The resulting preprocessed value is used as the criterion for determining the maximum resistance value.

[0085] S22. Determine the maximum torque value based on the preprocessed value and terminate the acquisition of torque value.

[0086] In the process of obtaining the resistance generated by the mixture, the test is terminated when several pre-processed values ​​are obtained continuously and exceed a preset unit value relative to the maximum pre-processed value. The maximum pre-processed value is obtained. Based on the maximum pre-processed value, the torque value corresponding to the maximum pre-processed value before filtering is obtained, which is the maximum torque value. Thus, the maximum resistance of the mixture flow can be obtained.

[0087] Specifically, in the process of obtaining discrete torque values, for each torque value obtained, a corresponding preprocessing value is calculated. The latest preprocessing value is compared with the previously obtained preprocessing values ​​to obtain a relatively higher preprocessing value. This relative preprocessing value is updated in real time during the acquisition of discrete torque values. When several consecutive preprocessing values ​​are all less than the relative preprocessing value, it indicates that the mixed slurry has reached dynamic equilibrium. The current preprocessing value is the maximum preprocessing value. Based on this maximum preprocessing value, the corresponding torque value can be determined, thus obtaining the maximum torque value and, consequently, the maximum resistance to the flow of the mixture.

[0088] When measuring the torque value of a rotor during rotation using a torque sensor, the uneven density and varying degrees of cross-linking in the mixture can easily cause fluctuations in the measured torque value. Even after filtering the torque value, the pre-processed value may still exhibit slight fluctuations. Therefore, by continuously acquiring several torque values ​​that gradually decrease until the maximum torque value is obtained, and then stopping the acquisition of torque values, the results are more accurate.

[0089] To examine the degree of fiberization in binders, samples are typically taken from the mixture to prepare self-supporting sheet-like samples (dry-process positive electrode samples, dry-process negative electrode samples, or dry-process electrolyte membrane samples). The self-supporting strength and tensile strength of these samples are then tested to determine the degree of fiberization in the mixture. Compared to conventional testing methods, this invention provides timely results, facilitating timely adjustment of the mixed slurry production process. Furthermore, it eliminates the need for sample preparation, preventing damage and waste to the mixture. The degree of fiberization exhibits a strictly monotonically increasing relationship with maximum resistance: the lower the degree of fiberization, the closer the material is to a loose granular state, with minimal obstruction during flow and low maximum resistance. As fiberization intensifies, the fiber structure becomes increasingly interwoven and dense, leading to a continuous increase in maximum resistance. This correlation shows no inverse fluctuation, ensuring the accuracy of the fiberization degree assessment.

[0090] It should be noted that the viscosity and maximum flow resistance of the mixed slurry are affected by factors such as materials and process requirements, and the maximum flow resistance of the mixed slurry may also be different. This application does not make specific limitations on the maximum flow resistance of the mixed material corresponding to the degree of fiberization, that is, the maximum torque value.

[0091] In some implementations, the degree of fiberization is evaluated for multiple batches of mixtures with different fiberization processes. The best fiberization process is obtained based on the maximum resistance of the mixture, wherein the greater the maximum resistance, the better the degree of fiberization. Therefore, the fiberization process corresponding to the mixture with the greater maximum resistance value is better.

[0092] Specifically, NCM:VGCF:PTFE are mixed evenly in a mass ratio of 96:2:2 and placed in a high shear force mixer for fiberization. The fiberization process parameters are: rotation speed 41m / s, time 2min, and the equipment is neither heated nor cooled to obtain fiberized material A.

[0093] NCM:VGCF:PTFE were mixed evenly in a mass ratio of 96:2:2 and then placed in a high shear force mixer for fiberization. The fiberization process parameters were: rotation speed 41m / s, time 4min, and the equipment was neither heated nor cooled to obtain the fiberized material B.

[0094] NCM:VGCF:PTFE were mixed evenly in a mass ratio of 96:2:2 and then placed in a high shear force mixer for fiberization. The fiberization process parameters were: rotation speed 38m / s, time 2min, and the equipment was neither heated nor cooled to obtain the fiberized material C.

[0095] The fiberized materials A, B, and C were taken out and put into the evaluation device for testing. The rotor 4 of the evaluation device was fixed at a speed of 5 m / s, the temperature was 80°C, and the pressure applied by the pressing rod 3 was 15 N. The three groups of fiberized materials A, B, and C were obtained respectively.

[0096] The time-torque curves for preparing three sets of materials are as follows: Figure 5 As shown.

[0097] from Figure 5 As can be seen from the data, the maximum torque values ​​of materials in groups A, B, and C are as follows: Group A reaches 15.5 N*m in 83 seconds, Group B reaches 20.1 N*m in 87 seconds, and Group C reaches 12.8 N*m in 49 seconds. Therefore, it can be concluded that the material in group B has a better degree of fiberization. When optimizing the fiberization process parameters of the material, the fiberization process parameters corresponding to group B can be selected.

[0098] In some implementations, multiple samples are taken from the same batch of mixture, and these samples are used to test the maximum resistance of the mixture. The difference between the maximum resistance of different samples, i.e., the difference between the maximum torque values, is compared. If the difference is within a preset range, it indicates that the batch of mixture is uniformly fiberized. Specifically, the preset range D is ±2%.

[0099] Specifically, LMO:SP:PTFE is mixed evenly in a mass ratio of 96:2:2 and placed in a high shear force mixer for fiberization. The fiberization process parameters are: rotation speed 41m / s, time 6min, temperature 60℃. The fiberized material is then divided into group D, group E, and group F.

[0100] The fiberized materials from groups D, E, and F (to reduce error, the weight error of each group should be controlled within ±0.1% during testing) were taken out and placed into the evaluation device for testing. The rotor 4 of the evaluation device was fixed at a speed of 6 m / s, the temperature at 80℃, and the pressure applied by the pressure rod 3 was 15 N. The time-torque curves of the fiberized materials from groups D, E, and F were obtained, as shown below. Figure 6 As shown.

[0101] from Figure 6 As can be seen from the data, the maximum torque values ​​of materials in groups D, E, and F are 14.9 N*m for group D at 42 seconds, 15.7 N*m for group E at 41 seconds, and 14.8 N*m for group F at 41 seconds. Therefore, it can be concluded that the fiberization degree of materials in groups D and F is more consistent. When preparing the materials, materials in groups D and F can be selected to maintain the consistency of the materials and optimize the performance of the batteries produced later.

[0102] It should be noted that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for evaluating the degree of fibrousness in dry-process battery mixtures, characterized in that, The evaluation method includes the following steps: S1. Detect the resistance generated by the flow of the fiberized mixture; S2. Analyze the maximum resistance based on the resistance, and evaluate the degree of fiberization of the mixture based on the maximum resistance.

2. The method for evaluating the degree of fibrosis in dry-process battery mixtures according to claim 1, characterized in that, The mixture includes battery materials and a fiberizable binder.

3. The method for evaluating the degree of fibrosis in dry-process battery mixtures according to claim 1, characterized in that, Step S1 includes: S11. The fiberized mixture is fed into the torque detection device; S12. The torque detection device stirs the mixture and detects the resistance to the flow of the mixture.

4. The method for evaluating the degree of fibrosis in dry-process battery mixtures according to claim 3, characterized in that, The torque detection device includes a mixture receiving unit, a mixture shearing unit, a drive unit, and a sensing unit. Step S11 includes feeding the mixture into the mixture receiving unit; Step S12 includes a drive unit on the outside of the mixture receiving unit driving the mixture shearing unit inside the mixture receiving unit to rotate, stirring the mixture, and a sensing unit on the mixture shearing unit detecting the torque value; the rotational speed R of the drive unit is in the range of R≤25r / s; The torque value reflects the resistance generated by the flow of the mixture.

5. The method for evaluating the degree of fibrosis in dry-process battery mixtures according to claim 4, characterized in that, Step S12 further includes applying a constant pressure, F ≤ 50 N, to the mixture in the mixture receiving unit by the pressure unit in the torque detection device.

6. The method for evaluating the degree of fibrosis in dry-process battery mixtures according to claim 4, characterized in that, Step S12 further includes regulating the constant temperature inside the mixture container unit by the temperature control unit in the torque detection device, wherein the temperature T is in the range of 20℃≤T≤120℃.

7. The method for evaluating the degree of fibrosis in dry-process battery mixtures according to claim 4, characterized in that, Step S2 includes, S21. Filter the acquired torque value to obtain a preprocessed value; S22. Determine the maximum torque value based on the preprocessed value and terminate the acquisition of torque value.

8. The method for evaluating the degree of fibrosis in dry-process battery mixtures according to claim 7, characterized in that, Step S22 includes: The test is terminated when several consecutive preprocessed values ​​obtained exceed a preset unit value relative to the maximum preprocessed value.

9. A method for evaluating the degree of fibrosis in dry-process battery mixtures according to any one of claims 1-8, characterized in that, Multiple samples are taken from the same batch of mixed materials. The samples are used as the maximum resistance test for the mixed materials. The difference between the maximum resistance of different samples is compared. If the difference is within a preset difference range, it indicates that the batch of mixed materials is uniformly fiberized. The preset difference range D is ±2%.

10. A method for evaluating the degree of fibrosis in dry-process battery materials according to any one of claims 1-8, characterized in that, The degree of fiberization was evaluated for multiple batches of mixtures with different fiberization processes, and the best fiberization process was obtained based on the maximum resistance of the mixture.

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