Equipment and method for testing uniformity of dry-method electrode powder and diaphragm of battery

Abstract

The invention relates to the technical field of battery electrode testing, and discloses equipment and a method for testing the uniformity of battery dry-method electrode powder and a diaphragm, and the method comprises the following steps: receiving a test request, determining to select a test mechanism according to a test mode in the test request, and putting a sample to be tested into the test mechanism; the driving mechanism is controlled by the control unit, and the upper pressure head is driven to move downwards to apply test pressure to the to-be-tested sample; and receiving resistivity data detected by the probe electrode, and analyzing the resistivity data to determine a uniformity characterization value of the to-be-tested sample so as to realize the uniformity test of the powder and the diaphragm. According to the invention, the uniformity of the powder and the diaphragm can be rapidly and accurately tested by the same equipment, the test cost is reduced, and the test efficiency and precision are improved.

Description

Technical Field

[0001] This invention relates to the field of battery electrode testing technology, and in particular to a testing device and method for the uniformity of dry electrode powder and film in batteries. Background Technology

[0002] Dry electrode technology is a major technological development direction for lithium batteries. Its success will significantly reduce production costs, energy consumption, and environmental pollution. At the same time, dry electrode technology is also a challenge that solid-state batteries must overcome; otherwise, their success will be difficult to achieve.

[0003] Currently, methods for detecting the uniformity of dry electrodes include scanning electron microscopy (SEM) and X-ray diffraction (EDX). These methods can only be used for micro-area measurements and are not suitable for production in small batches or larger.

[0004] To date, dry electrode technology has not achieved mass production success, mainly because dry stirring struggles to achieve good uniformity. To achieve good uniformity, the first step is to develop a testing method and equipment that meets the requirements for powder and film uniformity in mass production; only then can dry electrode technology move forward.

[0005] In the manufacturing process of dry-process battery electrodes, the uniformity of electrode powder dispersion and the structural uniformity of the formed film directly determine the battery's charge-discharge performance, cycle life, and safety. If the powder agglomerates or is unevenly distributed, or if the film has excessively large local density differences or material inhomogeneity, it will lead to uneven current distribution inside the battery, causing problems such as local overheating, lithium dendrite precipitation, and excessively rapid capacity decay, seriously affecting the quality and reliability of the battery product.

[0006] Currently, testing technologies for the uniformity of powders and films in dry-process battery electrodes have significant shortcomings. On the one hand, existing testing equipment mostly employs a single testing mode, meaning it can only test powders or films individually. This requires two independent sets of equipment, increasing equipment procurement costs and floor space, and necessitates switching between devices when testing different samples, making operation cumbersome and reducing testing efficiency. On the other hand, traditional testing methods rely heavily on indirect methods such as visual observation, X-rays, and weighing, measuring extremely small areas unsuitable for mass production. They cannot directly and accurately reflect the internal uniformity of powders and films, resulting in highly subjective and low-precision test results that fail to meet the high-precision, mass-production testing requirements of dry-process electrodes. Furthermore, normal material resistivity testing can only measure the overall resistivity of a sample, not the resistivity in different directions within the same sample. Commonly used material resistivity methods, even when measuring the resistivity of two samples of the same material, will not yield the same resistivity value; therefore, the internal uniformity of each sample is inconsistent. Thus, commonly used material resistivity measurement methods cannot detect the uniformity within a sample.

[0007] Therefore, there is an urgent need for a device and method that can simultaneously perform uniformity testing of powders and films, is easy to operate, and has high testing accuracy. Summary of the Invention

[0008] The purpose of this invention is to provide a testing device and method for the uniformity of powder and film in dry electrode production for batteries. This aims to address the problems of existing equipment, which relies on a single detection mode and indirect methods such as visual observation, weighing, and overall resistivity, failing to directly and accurately reflect the internal uniformity of powder and film. The test results are highly subjective and have low precision, making it difficult to meet the testing requirements of high-precision, batch, and high-efficiency production of dry electrodes. This invention enables rapid and accurate testing of powder and film uniformity using the same equipment, reducing testing costs and improving testing efficiency and accuracy.

[0009] This invention provides a testing device for the uniformity of dry-process electrode powder and film in batteries, comprising: The test equipment body has a drive mechanism installed on its upper part; An upper pressure head is located at the bottom of the drive mechanism. The upper pressure head is driven downward by the drive mechanism. When testing the uniformity of the membrane, an upper probe electrode is provided at the bottom of the upper pressure head. A base is located at the bottom of the test equipment body and directly below the upper pressure head. When testing the uniformity of powder, a lower probe electrode is provided on the base. The testing mechanism is set on the base or the upper pressure head. The testing mechanism includes a powder testing mechanism and a membrane testing mechanism. The powder testing mechanism is used to perform powder uniformity testing, and the membrane testing mechanism is used to perform membrane uniformity testing. A control module is connected to the drive mechanism and the test mechanism. The control module is used to control the switching of the voltage and current lines of the resistance test between the probes, and to control the drive mechanism and the test mechanism to perform uniformity testing according to the test request.

[0010] Preferably, the powder testing mechanism includes: a powder testing platform, a powder cylinder, a lower probe electrode, a probe insulating block, a boss, and an insulating pressure head; the powder testing platform is disposed on the base, the powder cylinder is disposed on the powder testing platform, the probe insulating block is disposed on the powder testing platform, the lower probe electrode is disposed inside the probe insulating block, the boss is disposed on the left and right sides of the powder testing platform, and the insulating pressure head is disposed inside the hole of the powder cylinder.

[0011] Preferably, the diaphragm testing mechanism includes: a diaphragm testing platform and a diaphragm measuring head; the diaphragm testing platform is disposed on the base, the diaphragm measuring head is disposed on the upper pressure head, the top of the diaphragm measuring head is provided with a hole sleeve that matches the upper pressure head, and the diaphragm measuring head is connected to the upper pressure head through the hole sleeve.

[0012] Preferably, the number of the upper probe electrodes is greater than or equal to four.

[0013] Preferably, the control module includes: an input unit, a processing unit, and a control unit; The input unit is used to receive test requests and process parameters and transmit the test requests to the control unit. The test requests include test mode, test pressure, and probe current and voltage line switching requirements. The control unit is used to control the drive mechanism to move the upper pressure head downward to perform a uniformity test on the sample according to the test request; The processing unit is used to receive the resistance and sample thickness detected by the probe electrode, calculate the resistivity, and determine the sample uniformity characterization value based on the resistivity.

[0014] This application also discloses a test method for the uniformity of battery dry electrode powder and film, applied to the aforementioned test equipment for the uniformity of battery dry electrode powder and film, characterized in that it includes: Receive a test request, determine the test facility based on the test mode in the test request, and place the sample to be tested into the test facility; The control unit controls the drive mechanism, which moves the upper pressure head downward to apply test pressure to the sample to be tested. The system receives resistance and sample thickness detected by different probe electrodes, calculates resistivity data, analyzes the resistivity data to determine the uniformity characterization value of the sample under test, so as to realize the uniformity test of powder and film.

[0015] Preferably, determining the selection of a testing organization based on the testing mode in the testing request includes: if the testing mode is a powder uniformity testing mode, then switching to a powder testing organization and controlling the powder testing organization to perform a uniformity test; If the test mode is the membrane uniformity test mode, then switch to the membrane test mechanism and control the membrane test mechanism to perform the uniformity test.

[0016] Preferably, when the test mode is the powder uniformity test mode, the sample to be tested is powder; the powder is placed into the barrel hole of the powder barrel and an insulating pressure head is installed. The upper pressure head moves downward under the drive of the drive mechanism. The insulating pressure head applies pressure to the powder to reach the test pressure and maintains it for a set time to obtain the resistivity data detected by the probe electrode. When the test mode is the membrane uniformity test mode, the sample to be tested is a membrane. The membrane insulating seat is placed on the membrane test stage, the membrane is placed on the membrane insulating seat, and the membrane measuring head is sleeved on the upper probe electrode. The membrane measuring head moves downward under the drive of the drive mechanism to apply pressure to the membrane to reach the test pressure and maintain it for a set time to obtain the resistivity data detected by the probe electrode.

[0017] Preferably, the analysis of the resistivity data to determine the uniformity characterization value of the sample to be tested includes: the probe spacing is a fixed known value; Set any two probe electrodes as a group of probes, obtain the resistivity between each group of probes, and randomly select the resistivity between a group of probes as the reference resistivity. The resistivity difference between each group of probes and the reference resistivity is determined, and the ratio between the resistivity difference and the reference resistivity is determined. The ratio is set as the uniformity characterization value of the sample to be tested.

[0018] Compared with the prior art, the beneficial effects of the present invention are as follows: The testing equipment of the present invention integrates a powder testing mechanism and a membrane testing mechanism, and can switch between them to test the uniformity of powder and membrane. It eliminates the need for two independent sets of equipment, reduces equipment cost and floor space, and improves equipment utilization.

[0019] By using multiple probe electrodes to collect resistivity data at different locations on the sample, and calculating the ratio of the resistivity difference to the reference resistivity as a uniformity characterization value, the internal uniformity of the sample can be directly and objectively reflected. This avoids the subjectivity and low precision problems of traditional indirect testing methods, and also avoids the fact that electron microscopy and X-ray methods can only test the uniformity of micro-regions, which is not suitable for the pilot and mass production needs of dry electrodes.

[0020] The control module enables automated control, allowing operators to complete the testing process simply by inputting a test request, eliminating the need for complex manual operations. At the same time, the equipment facilitates switching between testing mechanisms, significantly shortening the testing cycle and improving testing efficiency.

[0021] The test pressure can be flexibly set according to the sample characteristics, and it is suitable for testing dry electrode powders and films of different types and specifications of batteries, with broad application prospects. Attached Figure Description

[0022] 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 embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0023] Figure 1 This is a partial structural schematic diagram of the testing equipment for the uniformity of dry electrode powder and film in batteries according to the present invention; Figure 2 This is a schematic diagram of the structure of the powder testing station in an embodiment of the present invention; Figure 3 This is a schematic diagram of the structure of the diaphragm measuring head in an embodiment of the present invention; Figure 4 This is a schematic flowchart of the method for testing the uniformity of dry electrode powder and film in batteries according to the present invention. In the figure, 1. Upper pressure head; 2. Base; 3. Powder test stage; 4. Powder cylinder; 5. Upper probe electrode; 6. Probe insulating block; 7. Diaphragm test stage; 8. Diaphragm measuring head; 9. Insulating pressure head; 10. Boss; 11. Lower probe electrode. Detailed Implementation

[0024] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0025] In the description of this application, it should be understood that the terms "center", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0026] The terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, unless otherwise stated, "a plurality of" means two or more.

[0027] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection between two components. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0028] like Figure 1-3 As shown, the present invention provides a testing device for the uniformity of dry electrode powder and film in batteries, comprising: The test equipment body has a drive mechanism installed on its upper part. The upper pressure head 1 is located at the bottom of the drive mechanism. The upper pressure head 1 is driven to move downward by the drive mechanism. When testing the uniformity of the membrane, the upper probe electrode 5 is provided at the bottom of the upper pressure head 1. The base 2 is located at the bottom of the test equipment body and is positioned directly below the upper pressure head 1. When testing the uniformity of powder, the lower probe electrode 11 is provided on the base 2. The testing mechanism is set on the base 2 or the upper pressure head 1. The testing mechanism includes a powder testing mechanism and a membrane testing mechanism. The powder testing mechanism is used to perform powder uniformity testing, and the membrane testing mechanism is used to perform membrane uniformity testing. The control module is connected to the drive mechanism and the test mechanism. The control module is used to control the switching of the voltage and current lines of the resistance test between the probes, and to control the drive mechanism and the test mechanism to perform uniformity testing and switch the resistance lines according to the test request.

[0029] This testing equipment effectively tests the uniformity of dry-process battery electrode powder and membranes, exhibiting high accuracy and reliability. The drive mechanism moves the upper pressure head 1 downwards, applying stable and controllable pressure to the sample placed on the base 2, providing favorable conditions for testing. The upper probe electrode 5 and lower probe electrode 11 allow for accurate acquisition of electrical signals during testing, obtaining crucial data on powder and membrane uniformity. The separate setup of the powder testing mechanism and the membrane testing mechanism is highly targeted, meeting the needs of different test objects. For powders, it can detect the uniformity of their distribution in different areas, which is crucial for evaluating powder quality and subsequent battery electrode performance. The membrane testing mechanism can detect membrane thickness, resistivity, and other uniformity indicators, ensuring that the membrane quality meets battery production requirements. The control module significantly improves the automation level of the test. It can precisely control the operation of the drive mechanism and testing mechanism according to test requests, reducing human interference and improving the consistency and repeatability of test results. Meanwhile, the control module can also perform preliminary processing and analysis of the test data, providing operators with intuitive test results, which helps to identify problems and make adjustments in a timely manner.

[0030] Specifically, the drive mechanism is configured as an electric cylinder or a pneumatic cylinder. The output shaft of the drive mechanism is connected to the load cell. The load cell connection plate is located below the load cell, the upper probe electrode insulating plate is located below the load cell connection plate, the upper probe electrode seat is located below the upper probe electrode insulating plate, and the upper probe electrode 5 is located below the upper probe electrode seat. A left displacement sensor is located to the left of the upper probe electrode 5, and a right displacement sensor is located to the right of the upper probe electrode 5. The left and right displacement sensors are symmetrically arranged around the center line of the upper probe electrode 5, and the load cell is located on the center line of the upper probe electrode 5. The upper probe electrode 5 is connected to the output and input current lines and the output and input voltage lines, respectively; the lower probe electrode 11 is connected to the input current line and the input voltage line, respectively.

[0031] In this embodiment, the main body of the testing device serves as the support frame for the entire device, with a drive mechanism fixedly mounted on its upper part. The drive mechanism possesses precise displacement control and pressure adjustment capabilities, providing a stable downward moving force for the upper pressure head 1. The upper pressure head 1 is located at the bottom of the drive mechanism and is fixedly connected to the power output end of the drive mechanism. It can move downwards vertically under the drive of the drive mechanism. A diaphragm measuring head is fixedly installed at the bottom of the upper pressure head 1. The diaphragm measuring head is made of a metal material with excellent conductivity and mechanical properties (such as steel or tungsten) and is used to form a conductive circuit during the test. The diaphragm measuring head consists of four or more probes and is used to measure the resistivity and uniformity of the diaphragm.

[0032] The base 2 is fixedly installed at the bottom of the test equipment body and directly below the upper pressure head 1, ensuring that the upper pressure head 1 can accurately act on the test mechanism on the base 2 when it moves down. The lower probe electrode 11 is fixedly installed on the top of the base 2. The lower probe electrode 11 is made of the same material and matches the size of the upper probe electrode 5. The lower probe electrode 11 consists of 4 or more probes and is used to measure the resistivity or uniformity of powder materials. When the powder cylinder is removed, the resistivity and uniformity of the diaphragm can also be measured.

[0033] In some embodiments of this application, the powder testing mechanism includes: a powder testing platform 3, a powder cylinder 4, a lower probe electrode 11, a probe insulating block 6, a boss 10, and an insulating pressure head 9; the powder cylinder 4 is disposed on the powder testing platform 3, the probe insulating block 6 is disposed on the powder testing platform 3, the lower probe electrode 11 is disposed inside the probe insulating block 6, the boss 10 is disposed on the left and right sides of the powder testing platform, and the insulating pressure head 9 is disposed inside the hole of the powder cylinder.

[0034] Understandably, this powder testing apparatus further optimizes the testing of the uniformity of dry-process battery electrode powder. The powder testing platform 3 provides a stable support platform for the entire test, ensuring the smooth progress of the test process. The powder cylinder 4 facilitates the placement and fixation of powder samples, allowing the powder to maintain a relatively stable state during the test and reducing the interference of external factors on the test results. The combination of the lower probe electrode 11 and the probe insulating block 6 plays a crucial role. The lower probe electrode 11 can accurately collect electrical signals inside the powder, which reflect the electrical characteristics of the powder at different locations, thus allowing inferences about the uniformity of the powder. The probe insulating block 6 effectively isolates the current interference between electrodes, ensuring the accuracy and reliability of the collected electrical signals. This structural design enables the powder testing apparatus to detect the uniformity of powder through different current paths. It can detect uneven distribution of powder at internal levels, such as local agglomeration or voids. By analyzing this information, a deeper understanding of the powder's uniformity quality can be obtained, providing important reference for powder production and subsequent battery electrode preparation.

[0035] Specifically, the powder cylinder 4 of the present invention has an inner diameter of 10mm, 12mm, 14mm, etc., which is suitable for characterization during mass production; uniformity is a quantitative dimensionless index that is directly given by the instrument.

[0036] In this embodiment, the powder testing mechanism includes a powder testing platform 3, a powder cylinder 4, a lower probe electrode 11, a probe insulating block 6, a boss 10, and an insulating pressure head 9. Specifically: the powder testing platform 3 is a flat plate structure used to mount the lower probe electrode 11 and support the powder cylinder 4; the powder cylinder 4 is a cylindrical structure with an open top, placed on the powder testing platform 3, and has an internal cylinder hole for accommodating the powder to be tested. The size of the cylinder hole can be designed according to testing requirements (e.g., diameter 8-50mm, depth 5-20mm), and the insulating pressure head 9 is placed inside the cylinder hole. The probe insulating block 6 is made of a high-temperature resistant and highly insulating material (such as ceramic) and is embedded in the cylinder hole of the powder cylinder 4. Its interior has mounting holes that match the lower probe electrodes 11. There are four or more lower probe electrodes 11, which are metal needle-like structures (such as tungsten needles or stainless steel needles) and are fixedly installed in the mounting holes of the probe insulating block 6. The lower ends of the lower probe electrodes 11 extend into the cylinder hole to contact the powder to be tested and measure its resistivity. The multiple lower probe electrodes 11 are evenly distributed within the cylinder hole (e.g., circumferential, matrix, or linear distribution) to ensure that resistivity data from different locations on the powder can be collected.

[0037] In some embodiments of this application, the diaphragm testing mechanism includes: a diaphragm testing platform 7 and a diaphragm measuring head 8; the diaphragm testing platform 7 is disposed on a base, the diaphragm measuring head 8 is disposed on an upper pressure head, the top of the diaphragm measuring head 8 is provided with a hole sleeve that matches the upper pressure head, and the diaphragm measuring head 8 is connected to the upper pressure head 1 through the hole sleeve.

[0038] Understandably, this membrane testing mechanism enhances the testing capability for the uniformity of dry-process battery electrode membranes. The membrane testing platform 7 provides a stable testing foundation for the membrane, ensuring it remains flat, insulated, and stable during testing, preventing changes in membrane position from affecting the accuracy of test results. The orifice at the top of the membrane measuring head 8 precisely matches the upper pressure head, achieving a reliable connection between the membrane measuring head 8 and the upper pressure head, ensuring stable current conduction during testing.

[0039] The upper probe electrodes 5 at the bottom of the membrane measurement head 8 play a crucial role in the test. These upper probe electrodes 5 can make full contact with the membrane surface, accurately measuring the electrical parameters at different locations on the membrane. By analyzing these electrical parameters, the uniformity of the membrane can be accurately determined. For example, if there are local thickness differences or compositional inhomogeneities in the membrane, the electrical parameters collected by the upper probe electrodes 5 will change accordingly, thus enabling timely detection of membrane quality problems.

[0040] This requires a membrane testing facility capable of comprehensive and precise testing of membrane uniformity. It can detect non-uniformities at both the macroscopic and microscopic levels, including membrane surface thickness and internal component distribution. In-depth analysis of this information provides a comprehensive understanding of the membrane's quality, offering crucial reference data for membrane production and battery electrode fabrication.

[0041] In this embodiment, the membrane testing mechanism includes a membrane testing platform 7 and a membrane measuring head 8. The membrane testing platform 7 is a flat plate structure, fixedly mounted on a base, used to place the membrane to be tested. Its surface flatness error does not exceed 0.01 mm to ensure stable placement of the membrane. The membrane measuring head 8 has a perforated sleeve at its top that matches the upper pressure head, allowing it to be detachably fitted onto the upper pressure head for easy installation and replacement. An upper probe electrode 5 is fixedly mounted at the bottom of the membrane measuring head 8. The number of upper probe electrodes 5 is also greater than or equal to four, evenly distributed, used to contact the membrane to be tested and detect its resistivity. The material of the upper probe electrodes 5 may be different from that of the lower probe electrode 11 in the powder testing mechanism.

[0042] In some embodiments of this application, the number of upper probe electrodes 5 is greater than or equal to 4.

[0043] In this embodiment, the upper probe electrodes 5 can be any number of four or more, arranged at equal intervals or arbitrary spacing, and arranged in a straight line or any shape.

[0044] In some embodiments of this application, the control module includes: an input unit, a processing unit, and a control unit; the input unit is used to receive test requests and process parameters and transmit the test requests to the control unit, the test requests including test mode, test pressure, and current and voltage line switching requirements of the probe; the control unit is used to control the drive mechanism to move the upper pressure head 1 downward to perform a uniformity test on the sample according to the test request; the processing unit is used to receive the resistance and sample thickness detected by the lower probe electrode 11 or the diaphragm measuring head, calculate the resistivity, and determine the sample uniformity characterization value based on the resistivity.

[0045] Understandably, the control module provides an efficient, intelligent, and precise control mechanism for the uniformity testing of dry electrode powders and films in batteries. The input unit facilitates interaction between the operator and the testing equipment, allowing the operator to flexibly select test modes and pressures according to different testing needs, enabling the testing process to better adapt to diverse samples and testing scenarios. For example, different test modes and pressures can be selected for films or powder samples of different materials and thicknesses to ensure the accuracy and reliability of the test results.

[0046] The control unit can precisely control the drive mechanism to move the upper pressure head 1 downward according to the test request transmitted from the input unit, so that the upper pressure head 1 applies appropriate pressure to the sample, thereby ensuring that the test process is carried out according to the preset requirements. This precise control can avoid test errors caused by excessive or insufficient pressure, and improve the accuracy and repeatability of the test.

[0047] The processing unit is the key component for analyzing and processing test data. It receives resistivity data detected by the probe electrodes and determines the homogeneity characterization value of the sample based on this data. Through the analysis and processing of large amounts of resistivity data, the processing unit can delve into the homogeneity information within the sample, providing a scientific basis for judging sample quality. For example, if the sample exhibits localized inhomogeneity, the processing unit can accurately locate the inhomogeneous area by analyzing resistivity changes and provide the corresponding homogeneity characterization value, helping operators to promptly identify and resolve problems. This not only improves the accuracy and reliability of the test but also significantly enhances its efficiency. Operators only need to input the test request into the input unit, and the control module can automatically complete the entire testing process and quickly provide the sample's homogeneity characterization value. This reduces the complexity and error of manual operation, improving the efficiency and quality of the testing work.

[0048] like Figure 4 As shown, the present invention also discloses a test method for the uniformity of dry-process electrode powder and film in batteries, applied to the test equipment for the uniformity of dry-process electrode powder and film in batteries as described above, comprising: Receive a test request, determine the test facility based on the test mode in the test request, and place the sample to be tested into the test facility; The control unit controls the drive mechanism, which moves the upper pressure head downward to apply test pressure to the sample to be tested. The system receives resistance and sample thickness detected by different probe electrodes, calculates resistivity data, analyzes the resistivity data to determine the uniformity characterization value of the sample under test, so as to realize the uniformity test of powder and film.

[0049] This testing method enables rigorous testing of powder and film uniformity in the early stages of battery production, allowing for the timely detection of potential quality issues. Compared to traditional testing methods, this approach utilizes advanced testing equipment and analyzes resistivity data, avoiding errors from subjective judgment and significantly improving the accuracy and reliability of the test results.

[0050] In actual production, this testing method can significantly reduce the defect rate of battery production. Once a sample with non-uniformity is found, the manufacturer can quickly adjust the production process and optimize the production flow, thereby improving the overall quality of the battery electrodes. This not only helps to improve battery performance and stability, reduce battery failures and safety hazards caused by electrode quality problems, but also reduces production costs and improves the company's economic benefits.

[0051] In this embodiment, the uniformity characterization value is a dimensionless value.

[0052] In some embodiments of this application, determining the selection of a testing mechanism based on the testing mode in the test request includes: if the testing mode is a powder uniformity testing mode, then switching to a powder testing mechanism and controlling the powder testing mechanism to perform a uniformity test; if the testing mode is a membrane uniformity testing mode, then switching to a membrane testing mechanism and controlling the membrane testing mechanism to perform a uniformity test.

[0053] Understandably, this method enables flexible switching of testing modes, allowing for precise selection of the appropriate testing mechanism based on different testing requirements. For dry-process electrode production in batteries, the differences in the properties and characteristics of powder and film are key process points at different stages, and the testing requirements for their uniformity also differ. This solution addresses this by setting up separate powder and film testing mechanisms, automatically matching them according to the testing mode. This makes the testing process more closely aligned with actual needs, significantly improving the relevance and effectiveness of the testing.

[0054] This method of selecting a testing facility based on the testing mode simplifies the testing process. Operators only need to specify the testing mode in the test request, and the equipment will automatically select it without manual intervention or adjustment. This not only reduces the complexity and difficulty of operation and the possibility of human error, but also improves testing efficiency and shortens testing time.

[0055] In some embodiments of this application, when the test mode is the powder uniformity test mode, the sample to be tested is powder; the powder is placed into the barrel hole of the powder barrel and the insulating pressure head 9 is placed into the barrel hole. The upper pressure head moves downward under the drive of the drive mechanism, and the pressure is applied to the powder through the insulating pressure head 9 to reach the test pressure and maintain it for a set time to obtain the resistivity data detected by the probe electrode.

[0056] When the test mode is the membrane uniformity test mode, the sample to be tested is a membrane. Place the membrane insulating seat on the membrane test stage, place the membrane on the membrane insulating seat, and put the membrane measuring head on the upper probe electrode 5. The membrane measuring head moves downward under the drive of the drive mechanism, applies pressure to the membrane to reach the test pressure and maintains it for a set time, and obtains the resistivity data detected by the probe electrode.

[0057] Understandably, this application provides targeted testing procedures for samples under different testing modes, ensuring the accuracy and reliability of the test results. In the powder uniformity test, pressure is applied to the powder by an upper pressure head and maintained for a certain period of time, simulating the pressure state of the powder in actual applications. This makes the obtained resistivity data more reflective of the powder's uniformity in real-world environments. Moreover, this standardized pressure application process ensures consistency of test conditions for each test, reducing errors caused by fluctuations in test conditions and improving the repeatability of test results.

[0058] For diaphragm uniformity testing, placing the diaphragm measuring head on the upper pressure head 1 and applying pressure ensures a tight fit to the diaphragm, resulting in more accurate measurements. The diaphragm plays a crucial role in the dry electrode of a battery, and its uniformity directly affects battery performance. This testing method can comprehensively and meticulously detect the uniformity of the diaphragm, promptly identifying potential defects and non-uniform areas, thus providing strong support for diaphragm quality control.

[0059] In some embodiments of this application, analyzing the resistivity data to determine the uniformity characterization value of the sample to be tested includes: the probe spacing is a fixed known value, guaranteed by mechanical processing; setting any two probe electrodes as a group of probes, obtaining the resistivity between each group of probes, and randomly selecting the resistivity between a group of probes as the reference resistivity; determining the resistivity difference between the resistivity between each group of probes and the reference resistivity, and determining the ratio between the resistivity difference and the reference resistivity, and setting the ratio as the uniformity characterization value of the sample to be tested.

[0060] To further illustrate this application, the testing method of this application is illustrated with examples: Powder uniformity test Equipment preparation: Install the powder testing mechanism on the probe electrode under the base of the testing equipment body. The diameter of the powder barrel hole is 14mm and the depth is 10mm. Four probe electrodes are installed inside the probe insulating block, arranged in a straight line with equal spacing (3mm). Sample placement: Fill the powder of the dry electrode active material to be tested (such as lithium iron phosphate powder) into the barrel hole of the powder barrel, use a scraper to level the powder surface to ensure that the powder is densely packed, and then place the insulating pressure head in.

[0061] Test parameter settings: Set the test mode to "powder uniformity test mode" through the input unit, the test pressure to 2MPa, and the pressure maintenance time to 20s. Test run: The control unit controls the drive mechanism to move the upper pressure head downward, apply a pressure of 2MPa to the powder and maintain it for 20s; during this period, three probe electrodes collect resistivity data at different locations of the powder and transmit it to the processing unit. Data processing: Four probe electrodes are used to form four groups: AB, AC, BC, and CD. If the resistivity of group AB is R0=500Ω·cm, group AC is R1=510Ω·cm, and group BC is R2=495Ω·cm, then the uniformity characterization value of group AC is |510-500| / 500=0.02, and that of group BC is |495-500| / 500=0.01, indicating that the powder has good uniformity. Example 2: Diaphragm Uniformity Test Equipment preparation: Install the membrane testing mechanism on the probe electrodes under the base. The surface flatness error of the membrane testing stage is 0.005mm. Four probe electrodes are installed at the bottom of the membrane measuring head in a straight line (3mm apart). Sample placement: Lay the dry electrode membrane to be tested (100μm thick, 50mm in diameter) flat on the membrane test stage, and put the membrane measuring head onto the upper pressure head through the hole sleeve, ensuring that the probe electrode is aligned with the center area of ​​the membrane. Test parameter settings: Set the test mode to "diaphragm uniformity test mode" through the input unit, the test pressure to 3MPa, and the pressure maintenance time to 15s. Test run: The control unit controls the drive mechanism to move the upper pressure head and the diaphragm measuring head downward, apply a pressure of 3MPa to the diaphragm and maintain it for 15s; the four probe electrodes collect resistivity data at different positions of the diaphragm and transmit it to the processing unit. Data processing: The four probe electrodes were divided into six groups: AB, AC, AD, BC, BD, and CD. The resistivity of group AB was selected as R0 = 800 Ω·cm. The resistivity of the other groups were R1 = 805 Ω·cm, R2 = 798 Ω·cm, R3 = 810 Ω·cm, R4 = 795 Ω·cm, and R5 = 802 Ω·cm, respectively. The calculated uniformity values ​​of each group were all between 0.01 and 0.015, indicating that the film has good uniformity.

[0062] Understandably, the homogeneity characterization values ​​determined in this way can intuitively reflect the homogeneity of the sample under test in a quantitative form. By using a reference resistivity, the differences and ratios between the resistivity of other probe groups and this reference resistivity are calculated, allowing for objective comparison of the homogeneity between different samples. This provides a unified and accurate standard for the quality assessment of dry electrode powders and films for batteries, avoiding the limitations of previous subjective judgments or qualitative descriptions.

[0063] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the specific implementation of the present invention. Any modifications or equivalent substitutions that do not depart from the spirit and scope of the present invention should be covered within the scope of protection of the claims of the present invention.

Claims

1. A testing device for the uniformity of dry-process electrode powder and films in batteries, characterized in that, include: The test equipment body has a drive mechanism installed on its upper part; An upper pressure head is located at the bottom of the drive mechanism. The upper pressure head is driven downward by the drive mechanism. When testing the uniformity of the membrane, an upper probe electrode is provided at the bottom of the upper pressure head. A base is located at the bottom of the test equipment body and directly below the upper pressure head. When testing the uniformity of powder, a lower probe electrode is provided on the base. A testing mechanism is disposed on the base or the upper pressure head. The testing mechanism includes a powder testing mechanism and a membrane testing mechanism. The powder testing mechanism is used to perform powder uniformity testing, and the membrane testing mechanism is used to perform membrane uniformity testing. A control module is connected to the drive mechanism and the test mechanism. The control module is used to control the switching of the voltage and current lines of the resistance test between the probes, and to control the drive mechanism and the test mechanism to perform uniformity testing according to the test request.

2. The testing equipment for the uniformity of dry-process electrode powder and film in batteries according to claim 1, characterized in that, The powder testing mechanism includes: a powder testing platform, a powder cylinder, a lower probe electrode, a probe insulating block, a boss, and an insulating pressure head; the powder testing platform is disposed on the base, the powder cylinder is disposed on the powder testing platform, the probe insulating block is disposed on the powder testing platform, the lower probe electrode is disposed inside the probe insulating block, the boss is disposed on the left and right sides of the powder testing platform, and the insulating pressure head is disposed inside the hole of the powder cylinder.

3. The testing equipment for the uniformity of dry-process electrode powder and film in batteries according to claim 2, characterized in that, The diaphragm testing mechanism includes a diaphragm testing platform and a diaphragm measuring head; the diaphragm testing platform is disposed on the base, the diaphragm measuring head is disposed on the upper pressure head, the top of the diaphragm measuring head is provided with a hole sleeve that matches the upper pressure head, and the diaphragm measuring head is connected to the upper pressure head through the hole sleeve.

4. The testing equipment for the uniformity of dry-process electrode powder and film in batteries according to claim 3, characterized in that, The number of the upper probe electrodes is greater than or equal to 4.

5. The testing equipment for the uniformity of dry-process electrode powder and film in batteries according to claim 4, characterized in that, The control module includes: an input unit, a processing unit, and a control unit; The input unit is used to receive test requests and process parameters and transmit the test requests to the control unit. The test requests include test mode, test pressure, and probe current and voltage line switching requirements. The control unit is used to control the drive mechanism to move the upper pressure head downward to perform a uniformity test on the sample according to the test request; The processing unit is used to receive the resistance and sample thickness detected by the probe electrode, calculate the resistivity, and determine the sample uniformity characterization value based on the resistivity.

6. A method for testing the uniformity of dry-process electrode powder and films for batteries, applied to the testing equipment for testing the uniformity of dry-process electrode powder and films for batteries as described in any one of claims 1-5, characterized in that, include: Receive a test request, determine the test facility based on the test mode in the test request, and place the sample to be tested into the test facility; The control unit controls the drive mechanism, which moves the upper pressure head downward to apply test pressure to the sample to be tested. The system receives resistance and sample thickness detected by different probe electrodes, calculates resistivity data, analyzes the resistivity data to determine the uniformity characterization value of the sample under test, so as to realize the uniformity test of powder and film.

7. The method for testing the uniformity of dry electrode powder and film in batteries according to claim 6, characterized in that, The selection of a testing organization is determined according to the testing mode in the test request, including: if the testing mode is a powder uniformity test mode, then a powder testing organization is installed and the powder testing organization is controlled to perform a uniformity test. If the test mode is the membrane uniformity test mode, then switch to the membrane test mechanism and control the membrane test mechanism to perform the uniformity test.

8. The method for testing the uniformity of dry electrode powder and film in batteries according to claim 7, characterized in that, When the test mode is the powder uniformity test mode, the sample to be tested is powder; the powder is placed into the barrel hole of the powder barrel and an insulating pressure head is installed. The upper pressure head moves downward under the drive of the drive mechanism. The pressure is applied to the powder through the insulating pressure head to reach the test pressure and is maintained for a set time to obtain the resistivity data detected by the probe electrode. When the test mode is the membrane uniformity test mode, the sample to be tested is a membrane. The membrane insulating seat is placed on the membrane test stage, the membrane is placed on the membrane insulating seat, and the membrane measuring head is sleeved on the upper probe electrode. The membrane measuring head moves downward under the drive of the drive mechanism to apply pressure to the membrane to reach the test pressure and maintain it for a set time to obtain the resistivity data detected by the probe electrode.

9. The method for testing the uniformity of dry electrode powder and film in batteries according to claim 8, characterized in that, Analyzing the resistivity data to determine the uniformity characterization value of the sample under test includes: The probe spacing is a fixed, known value; Set any two probe electrodes as a group of probes, obtain the resistivity between each group of probes, and randomly select the resistivity between a group of probes as the reference resistivity. The resistivity difference between each group of probes and the reference resistivity is determined, and the ratio between the resistivity difference and the reference resistivity is determined. The ratio is set as the uniformity characterization value of the sample to be tested.

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