Battery water content determination methods, systems, devices, apparatuses, media, and products

Abstract

The application relates to a battery water content determination method, system, device, equipment, medium and product. Moisture determination is performed on a target battery electrode sample according to a first critical temperature, the water content of the electrode sample is obtained, and then the water content of the target battery is determined according to the water content of the electrode sample. The first critical temperature is the temperature at which the network structure formed by the cathode main material and the water-based binder in the target battery is destroyed. The method can accurately characterize the water content in the target battery.

Description

Technical Field

[0001] This application relates to the field of battery technology, and in particular to a method, system, apparatus, equipment, medium, and product for determining the water content of a battery. Background Technology

[0002] With the development of battery technology, the application range of batteries is becoming increasingly wide. In the battery production process, certain technical indicators are used as the main factors to measure the quality of battery performance.

[0003] Taking moisture as an example, moisture is a key indicator that needs to be strictly controlled during battery production. Factors such as high ambient humidity and the use of water-based binders can increase the moisture content during electrode preparation. If the moisture content of the baked battery does not meet a certain standard, the battery's capacity and internal resistance will be negatively affected, leading to a reduction in the battery's cycle performance and safety performance.

[0004] Therefore, there is an urgent need for a method to accurately characterize the water content in batteries. Summary of the Invention

[0005] Therefore, it is necessary to provide a method, system, device, equipment, medium, and product for determining the water content of batteries that can accurately characterize the water content in batteries, in order to address the above-mentioned technical problems.

[0006] In a first aspect, this application provides a method for determining the water content of a battery, the method comprising:

[0007] The moisture content of the electrode sample of the target battery is determined by performing a moisture determination based on the first critical temperature; the first critical temperature is the temperature at which the cross-linked network structure formed by the cathode material and the aqueous binder in the target battery is destroyed.

[0008] The water content of the target battery is determined based on the water content of the electrode sample.

[0009] In the battery water content determination method provided in this application embodiment, the water content of the electrode sample of the target battery is determined by performing a water content determination on the electrode sample according to a first critical temperature. Then, the water content of the target battery is determined based on the water content of the electrode sample. The first critical temperature is the temperature at which the cross-linked network structure formed by the cathode main material and the aqueous binder in the target battery is destroyed. In this method, the electrode sample of the target battery is heated to the first critical temperature that can destroy the cross-linked network structure formed by the cathode main material and the aqueous binder in the target battery. This causes the cross-linked network structure formed by the cathode main material and the aqueous binder in the target battery to be destroyed. The destruction of the cross-linked network structure allows the water trapped in the cross-linked network structure in the electrode sample to be completely released. In addition to the trapped water, other water in the electrode sample can also be completely released at this first critical temperature. Thus, it is equivalent to using the first critical temperature to determine the water content of the electrode sample. The determination is performed when all the water in the electrode sample has been completely released, thereby accurately determining the water content in the electrode sample. Furthermore, since the electrode sample is part of the target battery, the water content of the target battery can be accurately characterized by the water content in the electrode sample, provided that the water content in the electrode sample is accurately determined.

[0010] In one embodiment, the water content includes the actual water content; the water content of the electrode sample of the target battery is obtained by performing a moisture determination on the electrode sample according to a first critical temperature, including:

[0011] When the heating device is heated to the first critical temperature, the first sample tube containing the electrode sample is placed into the heating device to obtain the water content in the first sample tube.

[0012] The true water content of the electrode sample is obtained based on the water content in the first sample tube.

[0013] In the battery water content determination method provided in this application embodiment, after heating the heating device to a first critical temperature, a first sample tube containing an electrode sample is placed into the heating device to obtain the water content in the first sample tube, and the true water content of the electrode sample is obtained based on the water content in the first sample tube. In this method, by configuring a heating device capable of heating to the first critical temperature to heat the first sample tube containing the electrode sample, the electrode sample in the first sample tube can be heated to the first critical temperature, thereby accurately obtaining the water content in the first sample tube. Furthermore, by placing the first sample tube into the heating device after heating to the first critical temperature, the heating device is essentially placed in a stable heating state, ensuring that the first sample tube is heated stably after being placed in the heating device, thus enabling rapid acquisition of the water content in the first sample tube. Since the first sample tube includes the electrode sample, the water content in the first sample tube includes the water content in the electrode sample; therefore, the true water content of the electrode sample can be accurately obtained based on the water content in the first sample tube.

[0014] In one embodiment, the true water content of the electrode sample is obtained based on the water content in the first sample tube, including:

[0015] Obtain the water content in the empty sample tube; no electrode sample was placed in the empty sample tube.

[0016] The true water content of the electrode sample is determined based on the water content of the empty sample and the water content in the first sample tube.

[0017] The battery water content determination method provided in this application embodiment obtains the empty sample water content in the empty sample tube, and determines the true water content of the electrode sample based on the empty sample water content and the water content in the first sample tube; wherein, no electrode sample is placed in the empty sample tube. In this method, since there may be a certain amount of moisture in the environment of the first sample tube before the electrode sample is placed, the water content in the first sample tube actually includes the water content in the environment of the first sample tube and the water content of the electrode sample. Therefore, when determining the true water content of the electrode sample, it is necessary to consider the empty sample water content in the empty sample tube without the electrode sample, and then remove the empty sample water content from the water content in the first sample tube to obtain the true water content of the electrode sample, thereby improving the accuracy of the measured true water content of the electrode sample.

[0018] In one embodiment, the heating device includes a heating pipe and a heating unit, the heating pipe having a hollow structure in the middle; when the heating device is heated to a first critical temperature, a first sample tube containing an electrode sample is placed into the heating device, including:

[0019] When the heating pipe is heated to the first critical temperature by the heating unit, the first sample tube is placed into the cavity of the heating pipe.

[0020] In the battery water content determination method provided in this application embodiment, the heating device includes a heating pipe and a heating unit. The heating pipe has a hollow cavity structure in the middle. After the heating pipe is heated to a first critical temperature by the heating unit, a first sample tube is placed into the cavity of the heating pipe. In this method, the heating pipe is heated to the first critical temperature before the first sample tube is placed into the cavity of the heating pipe. This is equivalent to first placing the heating pipe in a heated and stable state, so that the first sample tube is heated and stabilized after being placed in the heating pipe, thereby enabling rapid acquisition of the water content in the first sample tube.

[0021] In one embodiment, the first sample tube is a long-necked sample tube, and the distance between the opening of the long-necked sample tube and the heating unit is greater than a preset distance.

[0022] In the battery water content determination method provided in this application embodiment, the sample tube is a long-necked sample tube, and the distance between the opening of the sample tube and the heating unit is greater than a preset distance. In this method, by setting the distance between the opening of the first sample tube and the heating unit to be greater than the preset distance, the opening of the first sample tube is moved away from the heating area of ​​the heating unit. For example, by making the distance between the opening of the first sample tube and the heating unit greater than the preset distance, the opening of the first sample tube will not lose its sealing performance due to heat, thereby improving the sealing performance of the first sample tube.

[0023] In one embodiment, the first sample tube includes an inlet and an outlet; the inlet is connected to an inlet pipe, and the outlet is connected to an electrolytic cell via an outlet pipe; obtaining the water content in the first sample tube includes:

[0024] When dry gas enters the first sample tube through the inlet pipe and water vapor generated by heating the electrode sample is sent into the electrolytic cell through the outlet pipe, the water content in the first sample tube is determined based on the amount of electricity generated during the electrolysis process of the water vapor in the electrolytic cell.

[0025] In the battery water content determination method provided in this application embodiment, the first sample tube includes an inlet and an outlet. The inlet is connected to an inlet pipe, and the outlet is connected to the electrolytic cell through an outlet pipe. When dry gas enters the first sample tube through the inlet pipe and water vapor generated by heating the electrode sample is sent into the electrolytic cell through the outlet pipe, the water content in the first sample tube is determined based on the amount of electricity generated by the electrolysis process of the water vapor in the electrolytic cell. In this method, water vapor in the first sample tube is vented using a dry gas, preventing an increase in water vapor in the first sample tube due to the introduction of dry gas. Furthermore, the dry gas enters the first sample tube through an inlet pipe, while water vapor generated by the electrode sample is sent to the electrolytic cell through an outlet pipe. By transporting the dry gas and water vapor through two separate gas pipes, all water vapor in the first sample tube can enter the electrolytic cell while the dry gas is being vented into the first sample tube, thus improving the accuracy of determining the water content in the first sample tube. In addition, water vapor in the first sample tube can be obtained simply by supplying dry gas to the first sample tube, allowing the determination of the water content in the first sample tube based on the water vapor content, thereby improving the convenience of determining the water content in the first sample tube.

[0026] In one embodiment, the water content includes free water content and bound water content. The water content of the electrode sample of the target battery is obtained by performing a moisture determination on the sample based on a first critical temperature, including:

[0027] Moisture content of the electrode sample is determined by performing a moisture determination on the second sample tube containing the electrode sample based on the second critical temperature; the second critical temperature is lower than the first critical temperature.

[0028] After the free water content of the electrode sample is determined, the moisture content of the second sample tube is determined according to the first critical temperature to obtain the bound water content of the electrode sample.

[0029] In the battery water content determination method provided in this application embodiment, a water content determination is performed on a second sample tube containing an electrode sample according to a second critical temperature to obtain the free water content of the electrode sample; the second critical temperature is lower than the first critical temperature; after the free water content determination of the electrode sample is completed, a water content determination is performed on the second sample tube according to the first critical temperature to obtain the bound water content of the electrode sample. This method obtains the free water content and bound water content of the electrode sample by performing water content determination at different critical temperatures, and identifies different forms of water content through different critical temperatures. This allows for the comprehensive release of any form of water content in the electrode sample, ensuring that any form of water content can be effectively and accurately determined.

[0030] In one embodiment, a moisture determination is performed on a second sample tube containing an electrode sample based on a second critical temperature to obtain the free water content of the electrode sample, including:

[0031] When the heating device is heated to the second critical temperature, the second sample tube containing the electrode sample is placed into the heating device to obtain the water content in the second sample tube.

[0032] The free water content of the electrode sample is determined based on the water content in the second sample tube.

[0033] In the battery water content determination method provided in this application embodiment, a second sample tube containing an electrode sample is placed into the heating device after heating the heating device to a second critical temperature, and the water content in the second sample tube is obtained; based on the water content in the second sample tube, the free water content of the electrode sample is determined. In this method, the second critical temperature allows the free water in the electrode sample to be completely released; therefore, the water content in the second sample tube can be accurately obtained at the second critical temperature. Furthermore, the water content in the second sample tube includes the free water content of the electrode sample; therefore, based on the water content in the second sample tube, the free water content of the electrode sample can be accurately obtained.

[0034] In one embodiment, determining the free water content of the electrode sample based on the water content in the second sample tube includes:

[0035] Obtain the water content in the empty sample tube; no electrode sample was placed in the empty sample tube.

[0036] The free water content of the electrode sample is determined based on the water content of the empty sample and the water content in the second sample tube.

[0037] In the battery water content determination method provided in this application embodiment, the empty sample water content in the empty sample tube is obtained, and the free water content of the electrode sample is determined based on the empty sample water content and the water content in the second sample tube; wherein, no electrode sample is placed in the empty sample tube. Since there may be a certain amount of moisture in the environment of the second sample tube before the electrode sample is placed, the water content in the second sample tube actually includes the water content in the environment of the second sample tube and the free water content of the electrode sample. Therefore, when determining the free water content of the electrode sample, it is necessary to consider the empty sample water content in the empty sample tube without the electrode sample, and then remove the empty sample water content from the water content in the second sample tube to obtain the free water content of the electrode sample, thereby improving the accuracy of the measured free water content of the electrode sample.

[0038] In one embodiment, a moisture determination is performed on the second sample tube based on a first critical temperature to obtain the bound water content of the electrode sample, including:

[0039] Remove the second sample tube from the heating device, and then put the second sample tube back into the heating device while heating the device to the first critical temperature to obtain the bound water content of the electrode sample.

[0040] In the battery water content determination method provided in this application embodiment, a second sample tube is removed from the heating device, and after the heating device is heated to a first critical temperature, the second sample tube is placed back into the heating device to obtain the bound water content of the electrode sample. In this method, the step of placing the second sample tube into the heating device to obtain the bound water content of the electrode sample is performed after determining the free water content of the electrode sample in the second sample tube. At this time, the free water of the electrode sample in the second sample tube has been completely evaporated, leaving only the bound water that has not evaporated at the second critical temperature. Therefore, by placing the second sample tube back into the heating device to perform water content determination after heating the device to the first critical temperature, the bound water content of the electrode sample can be accurately obtained.

[0041] In one embodiment, the method further includes, prior to performing the moisture determination:

[0042] The drift value in the gas measurement environment is controlled to be less than a preset drift threshold by using a drift-stabilized empty sample tube.

[0043] In the battery water content determination method provided in this application embodiment, before performing the water content determination, the drift value in the gas measurement environment is controlled to be less than a preset drift threshold by using a drift stabilizing empty sample tube. In this method, before each water content determination, in order to remove other interfering factors in the gas measurement environment, such as moisture and incomplete sealing, it is necessary to control the drift value in the gas measurement environment to be stable below the preset drift threshold, so that subsequent water content determination operations are carried out in a completely undisturbed environment, improving the accuracy of the water content determination results. Furthermore, by using a drift stabilizing empty sample tube to stabilize the drift value in the water content determination system below the preset drift threshold, the speed of determining the battery water content is increased.

[0044] In one embodiment, before performing a moisture determination on the electrode sample of the target battery based on a first critical temperature, the method further includes:

[0045] Once the target battery has been baked, the battery electrodes in the target battery are cut to obtain electrode samples of the target battery; the electrode samples are sheet-shaped electrodes of a preset size.

[0046] In the battery water content determination method provided in this application embodiment, before performing water content determination on the electrode sample of the target battery according to the first critical temperature, the battery electrodes in the target battery are cut after the target battery has been baked to obtain the electrode sample of the target battery; the electrode sample is a sheet-like electrode of a preset size. In this method, since baking is a necessary process in the preparation of the target battery, it can evaporate some of the water in the battery. Therefore, when characterizing the water content of the target battery, it is necessary to collect samples from the battery electrodes in the baked target battery. In this way, the water content of the target battery can be accurately characterized based on the water content of the electrode sample. Furthermore, since the electrode sample is of a preset size, the water in the preset-sized electrode sample can be fully released, thus accurately obtaining the water content in the electrode sample.

[0047] Secondly, this application provides a water content determination system, which includes: a water content testing system including: a heating device and an electrolytic cell; a sample tube placed in the heating device is connected to the electrolytic cell through a gas pipeline;

[0048] The electrode sample built into the sample tube is used to generate water vapor when the temperature of the heating device reaches the first critical temperature; the first critical temperature is the temperature at which the cross-linked network structure formed by the cathode main material and the aqueous binder in the target battery is destroyed.

[0049] Gas pipelines are used to transport water vapor to the electrolytic cell to obtain the water content of the electrode sample.

[0050] The water content determination system provided in this application includes a heating device and an electrolytic cell. A sample tube placed in the heating device is connected to the electrolytic cell through a gas pipeline. An electrode sample built into the sample tube is used to generate water vapor when the temperature of the heating device reaches a first critical temperature. The gas pipeline is used to transport the water vapor to the electrolytic cell to obtain the water content of the electrode sample. The first critical temperature is the temperature at which the cross-linked network structure formed by the cathode main material and the water-based binder in the target battery is destroyed. In this system, a heating device capable of reaching a first critical temperature is configured to heat the electrode sample in the sample tube to a temperature that disrupts the cross-linked network structure formed by the cathode material and the water-based binder. This disruption allows the water trapped within the cross-linked network to be completely released. In addition to the trapped water, other water in the electrode sample is also completely released at this first critical temperature. Therefore, the water content of the electrode sample is determined using the first critical temperature, assuming all water has been released, thus enabling accurate measurement. Furthermore, by connecting the sample tube to the electrolytic cell via a gas pipeline, water vapor from the sample tube is directly transported to the electrolytic cell to obtain the water content of the electrode sample, improving the speed of water content determination.

[0051] In one embodiment, the heating device includes a heating pipe and a heating unit, wherein the heating pipe has a hollow structure in the middle, and the sample tube is placed inside the hollow structure of the heating pipe.

[0052] In the water content determination system provided in this application embodiment, the heating device includes a heating pipe and a heating unit. The heating pipe has a hollow structure in the middle, and the sample tube is placed inside the hollow structure of the heating pipe. The heating unit is positioned directly in front of the electrode sample in the sample tube. In this system, placing the sample tube inside the hollow structure of the heating pipe allows the heating unit to heat the electrode sample. The moisture in the electrode sample can be completely evaporated under the heating of the heating unit, thereby enabling accurate determination of the water content of the electrode sample.

[0053] In one embodiment, the sample tube is a long-necked sample tube, and the distance between the opening of the sample tube and the heating unit is greater than a preset distance; the sample tube is capable of withstanding high-temperature resistant materials with a temperature greater than the first critical temperature.

[0054] In the water content determination system provided in this application embodiment, the sample tube is a long-necked sample tube, and the distance between the sample tube opening and the heating unit is greater than a preset distance; the sample tube is made of a high-temperature resistant material capable of withstanding temperatures above a first critical temperature. In this system, by setting the distance between the sample tube opening and the heating unit to be greater than a preset distance, the sample tube opening is moved away from the heating area of ​​the heating unit. For example, by making the distance between the opening of the first sample tube and the heating unit greater than a preset distance, the sample tube opening will not lose its sealing performance due to heat, thereby improving the sealing performance of the sample tube.

[0055] In one embodiment, the gas pipeline includes an inlet pipeline and an outlet pipeline. The inlet of the sample tube is connected to an air pump through the inlet pipeline, and the outlet of the sample tube is connected to an electrolytic cell through the outlet pipeline.

[0056] An air pump is used to deliver dry gas to the sample tube through an inlet pipe, so that water vapor in the sample tube can be transferred to the electrolytic cell through an outlet pipe.

[0057] In the water content determination system provided in this application embodiment, the gas pipeline includes an inlet pipeline and an outlet pipeline. The inlet of the sample tube is connected to an air pump through the inlet pipeline, and the outlet of the sample tube is connected to an electrolytic cell through the outlet pipeline. The air pump is used to deliver dry gas to the sample tube through the inlet pipeline to transfer water vapor in the sample tube to the electrolytic cell through the outlet pipeline. In this system, by using dry gas to vent the water vapor in the sample tube, the water vapor in the first sample tube will not increase due to the introduction of dry gas. Furthermore, the dry gas enters the sample tube through the inlet pipeline, and the water vapor in the sample tube is sent to the electrolytic cell through the outlet pipeline. By delivering dry gas and water vapor through two separate gas pipelines, all the water vapor in the sample tube can enter the electrolytic cell when the dry gas is vented into the sample tube, improving the accuracy of determining the water content in the sample tube. In addition, water vapor in the sample tube can be obtained simply by delivering dry gas to the sample tube, and the water content in the sample tube can be determined based on the water vapor, improving the convenience of determining the water content in the sample tube.

[0058] In one embodiment, a heating band is wrapped around the outer edge of the outlet pipe; the heating band is used to prevent water vapor in the sample tube from condensing in the outlet pipe.

[0059] In the water content determination system provided in this application embodiment, by wrapping a heating belt around the outer ring of the gas outlet pipe, the water vapor released by the electrode sample will not condense in the gas outlet pipe, thereby improving the accuracy of the determination results.

[0060] In one embodiment, the air intake pipe is connected to the air intake port and the air outlet pipe is connected to the air outlet port through multiple adapters, and the connection of each adapter is sealed with a sealing ring.

[0061] In the water content determination system provided in this application embodiment, the inlet pipe and the outlet pipe are connected by multiple adapters, and the connection points of each adapter are sealed with sealing rings. By using multiple adapters to connect the inlet pipe and the outlet pipe to the outlet, and sealing the connection points of each adapter with sealing rings, the sealing performance between the inlet pipe and the inlet of the sample tube, and between the outlet pipe and the outlet of the sample tube, is improved, thereby enhancing the overall sealing performance of the water content determination system.

[0062] Thirdly, embodiments of this application provide a battery water content measuring device, the device comprising:

[0063] The acquisition module is used to perform moisture determination on the electrode sample of the target battery according to the first critical temperature to obtain the water content of the electrode sample; the first critical temperature is the temperature at which the cross-linked network structure formed by the cathode main material and the water-based binder in the target battery is destroyed;

[0064] The determination module is used to determine the water content of the target battery based on the water content of the electrode sample.

[0065] Fourthly, embodiments of this application provide a computer device including a memory and a processor. The memory stores a computer program, and the processor executes the computer program to implement the method steps of any of the embodiments in the first aspect described above.

[0066] Fifthly, embodiments of this application provide a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the method steps of any of the embodiments in the first aspect described above.

[0067] Sixthly, embodiments of this application provide a computer program product, which includes a computer program that, when executed by a processor, implements the method steps of any of the embodiments in the first aspect described above.

[0068] The above description is only an overview of the technical solution of this application. In order to better understand the technical means of this application and to implement it in accordance with the contents of the specification, and to make the above and other objects, features and advantages of this application more obvious and understandable, the following are specific embodiments of this application. Attached Figure Description

[0069] Figure 1a This is a schematic diagram illustrating the thought process for studying the moisture release mechanism of the electrode in one embodiment;

[0070] Figure 1b This is a schematic diagram of the test results for studying the moisture release mechanism of the electrode in one embodiment;

[0071] Figure 1c This is a schematic diagram of the test results for studying the electrode moisture release mechanism in another embodiment;

[0072] Figure 1d This is a schematic diagram of the test results for studying the electrode moisture release mechanism in another embodiment;

[0073] Figure 1e This is a schematic diagram of the test results for studying the electrode moisture release mechanism in another embodiment;

[0074] Figure 1f This is a schematic diagram of the test results for studying the electrode moisture release mechanism in another embodiment;

[0075] Figure 1g This is a schematic diagram of the test results for studying the electrode moisture release mechanism in another embodiment;

[0076] Figure 2 This is a schematic diagram of the water content determination system in one embodiment;

[0077] Figure 3 This is a schematic diagram of the water content determination system in another embodiment;

[0078] Figure 4 This is a schematic diagram of the water content determination system in another embodiment;

[0079] Figure 5 This is a schematic diagram of the water content determination system in another embodiment;

[0080] Figure 6 This is a schematic diagram of the water content determination system in another embodiment;

[0081] Figure 7 This is a schematic diagram of the water content determination system in another embodiment;

[0082] Figure 8 This is a schematic diagram of the water content determination system in another embodiment;

[0083] Figure 9 This is a flowchart illustrating a method for determining the water content of a battery in one embodiment;

[0084] Figure 10 This is a flowchart illustrating the battery water content determination method in another embodiment;

[0085] Figure 11 This is a flowchart illustrating the battery water content determination method in another embodiment;

[0086] Figure 12 This is a flowchart illustrating the battery water content determination method in another embodiment;

[0087] Figure 13 This is a flowchart illustrating the battery water content determination method in another embodiment;

[0088] Figure 14 This is a flowchart illustrating the battery water content determination method in another embodiment;

[0089] Figure 15 This is a schematic diagram illustrating the performance verification results of a water content determination system in one embodiment;

[0090] Figure 16 This is a schematic diagram illustrating the performance verification results of the water content determination system in another embodiment;

[0091] Figure 17 This is a schematic diagram illustrating the performance verification results of the water content determination system in another embodiment;

[0092] Figure 18 This is a flowchart illustrating the battery water content determination method in another embodiment;

[0093] Figure 19 This is a structural block diagram of a battery water content measuring device in one embodiment;

[0094] Figure 20 This is an internal structural diagram of a computer device in one embodiment.

[0095] Explanation of reference numerals in the attached figures:

[0096] 20 Heating device; 21 Electrolytic cell;

[0097] 22 Sample tube; 23 Gas tubing;

[0098] 24. Electrode samples; 31. Heating pipes;

[0099] 32 Heating unit; 51 Intake pipe;

[0100] 52. Air outlet pipe; 53. Air pump;

[0101] 61. Titration cup; 62. Electrode;

[0102] 63 Karl Fischer anodic reagent; 64 Karl Fischer cathodic reagent;

[0103] 71. Heating belt. Detailed Implementation

[0104] The embodiments of the technical solution of this application will now be described in detail with reference to the accompanying drawings. These embodiments are only used to more clearly illustrate the technical solution of this application and are therefore merely examples, and should not be used to limit the scope of protection of this application.

[0105] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the application; the terms "comprising" and "having," and any variations thereof, in the specification, claims, and accompanying drawings of this application are intended to cover non-exclusive inclusion. In the description of embodiments of this application, technical terms such as "first," "second," etc., are used only to distinguish different objects and should not be construed as indicating or implying relative importance or implicitly specifying the number, specific order, or primary or secondary relationship of the indicated technical features. In the description of embodiments of this application, "a plurality of" means two or more, unless otherwise explicitly defined.

[0106] In this document, the term "embodiment" means that a specific feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments. Those skilled in the art will understand the specific meaning of the above terms in the embodiments of this application according to the specific circumstances.

[0107] Typically, in the battery manufacturing process, moisture is a key indicator that needs to be strictly controlled. Factors such as high ambient humidity and the use of water-based binders can lead to an increase in moisture content during electrode preparation.

[0108] Taking lithium-ion batteries as an example, if the moisture content of a baked lithium-ion battery does not reach a certain standard, the electrolyte will decompose and produce gas, affecting the battery manufacturing process. This will reduce the consistency of cell capacity and internal resistance, leading to a decrease in the battery's cycle performance and safety performance.

[0109] In related technologies, battery electrode packs with different moisture contents were prepared by adjusting the lithium-ion battery manufacturing process, and their full-cell formation and electrochemical cycling processes were tracked and tested. The results show that different moisture contents have a significant impact on the full-cell formation process and cycle performance. When the moisture content is less than 550 × 10⁻⁶, the moisture content is significantly lower than that of the battery. －6 Battery manufacturing process consistency and cycle performance are less affected by moisture factors. When the battery moisture content is greater than 700×10 －6 When the battery's cycle performance deteriorates significantly, product consistency cannot be guaranteed. Therefore, accurately measuring the battery's moisture content is crucial.

[0110] The Karl Fischer coulometric moisture analyzer is recognized by many countries as the most accurate measuring instrument, suitable for solid, liquid, and gas samples. The Karl Fischer coulometric moisture analyzer mainly consists of a Karl Fischer electrolytic cell and a sample heating unit. The sample is placed in a sealed sample vial, which is then heated to 170°C. The moisture in the sample evaporates, and the water vapor is then sent into the electrolytic cell to participate in the reaction using a dry gas. The amount of electricity generated during the electrolysis process is measured to determine the moisture content.

[0111] However, experimental testing revealed a linear relationship between electrode moisture content and temperature. The water content measured by the Karl Fischer moisture analyzer at 170°C does not represent all the moisture contained in the electrode. In other words, the Karl Fischer moisture analyzer cannot characterize the true water content inside the electrode at 170°C, nor can it distinguish between different forms of water. This makes it impossible to effectively analyze the source and evolution of electrode moisture and the impact of the electrode on the cell performance based on the Karl Fischer moisture analyzer's measurement results.

[0112] Based on this, the mechanism of moisture release from the electrode is analyzed, such as... Figure 1a As shown, the reasons for the linear increase in moisture were studied through verification of the measurement system, the water release law of single-component formulation, two-component formulation, and other aspects.

[0113] The verification of the measurement system included a comparison between the measuring instrument in the related technology and the water content measurement system. The verification results showed that the measuring instrument in the related technology was consistent with the water content measurement system and the test was reliable.

[0114] The moisture release patterns of the single components in the formulation include: ferrophosphorus (lithium iron phosphate) main material, conductive carbon, N-methylpyrrolidone, water-based binder, and 72A metal carbon spring steel wire. Among them, ferrophosphorus main material showed that the moisture content of the electrode plateaued at a certain temperature, with no moisture release at higher temperatures. Conductive carbon showed no change in electrode moisture content. N-methylpyrrolidone showed side reactions in the electrode, but the amount of water produced was extremely small. Water-based binder showed a linear increase in electrode moisture, possibly due to water encapsulation during manufacturing, but the content was relatively low compared to the electrode itself. Metal carbon spring steel wire 72A showed side reactions in the electrode, but the amount of water produced was extremely small.

[0115] The formulation of two components follows a pattern including dry mixing of ferrophosphorus and water-based binder and wet mixing of ferrophosphorus and water-based binder. Dry mixing of ferrophosphorus and water-based binder revealed that the moisture content of the electrode plateaus at a certain temperature, while wet mixing of ferrophosphorus and water-based binder revealed that the moisture content of the electrode plate increases linearly.

[0116] Other validations included tests before and after cold pressing, extended time and reheating, sample quantity comparison, and powder scraping + extraction + liquid moisture. The test results showed that the moisture content of the electrode increased linearly before and after cold pressing, but there was no fundamental difference before and after cold pressing. The extended time and reheating tests showed that temperature is the key factor for moisture release from the electrode. The sample quantity comparison test showed that the moisture content of the electrode still increased linearly when the sample quantity was very small. The powder scraping + extraction + liquid moisture test showed that a moisture plateau appeared after 20 hours of extraction, with a water content greater than 1500 ppm.

[0117] Based on the above test results, it was found that the measuring system, single-component formulation, electrode state, and sample amount were not the causes of the linear increase in electrode moisture. The two-component formulation may be the cause of the linear increase in electrode moisture. Therefore, the water content was further tested after dry mixing and wet mixing of the cathode material and water-based binder powder; the cathode material can be either ferrophosphorus or ternary cathode.

[0118] Taking a cathode made of ferrophosphorus phosphorus and a water-based binder of polyvinylidene fluoride (PVDF) as an example, such as Figure 1b and Figure 1c As shown, Figure 1b The water content resulting from the dry mixing of ferrophosphorus and water-based binder powder. Figure 1c The water content resulting from the wet mixing of ferrophosphorus and PVDF powder, from Figure 1b and Figure 1c It can be seen that when the dry mixture of ferrophosphorus and PVDF powder reaches a plateau at around 230℃, the water content of the wet mixture of ferrophosphorus and PVDF powder continues to increase.

[0119] Therefore, it can be determined that the wet mixing of the cathode material and the aqueous binder in the battery is the main reason for the linear increase in moisture, and temperature is the key factor for moisture release.

[0120] Furthermore, the electrode was experimentally analyzed using thermogravimetric analysis and online mass spectrometry coupled with adsorption spectroscopy (TPD-MS). The experimental results are as follows: Figure 1d and Figure 1e As shown in the figure, the experimental results indicate that the peak temperature of PVDF is approximately 450℃, and the moisture content gradually increases during the heating process.

[0121] Therefore, it can be determined that during the wet mixing process of the cathode material and the water-based binder, the water-based binder forms a cross-linked network structure with the cathode material (phosphorus iron or ternary cathode), encapsulating moisture within it, such as... Figure 1f As shown, during the heating process, the water-based binder gradually decomposes due to heat, causing the cross-linked network structure to gradually break down and releasing moisture.

[0122] Therefore, the electrode was further tested using TPD-MS, and the test results are as follows: Figure 1gIt is known that by first heating to a temperature sufficient to release all the free water in the electrode, and then holding that temperature for a certain period, followed by further heating, the cross-linked network structure formed by the aqueous binder and the main material gradually decomposes and breaks down due to the heat, releasing the bound water until all the bound water is released. Experimental analysis clarified the boundary temperatures corresponding to different binding forms of water in the battery electrode.

[0123] Based on the above analysis, in order to accurately characterize the true water content of the battery, this application designs a method for determining the water content of the battery. By performing a moisture determination on the electrode sample of the target battery at a first critical temperature, the water content of the electrode sample can be obtained. Since the first critical temperature is the temperature at which the cross-linked network structure formed by the cathode main material and the water-based binder in the target battery is destroyed, the water content of the electrode sample can be obtained at the first critical temperature. Under the premise of accurately determining the water content in the electrode sample, the water content in the electrode sample can be used to accurately characterize the water content of the target battery.

[0124] The technical effects that the battery water content determination method and water content determination system provided in this application embodiment can achieve are not limited to these, and can also achieve other technical effects. For example, the water content determination system overcomes the defect of the Karl Fischer coulomb micro moisture analyzer in related technologies, which can only be heated to a certain temperature, by structural modification. By heating the water content determination system to different boundary temperatures, quantitative characterization of water in different binding forms can be achieved.

[0125] It should be noted that the water content determination system provided in this application embodiment can, but is not limited to, determine the water content of the electrode.

[0126] The battery water content determination method provided in this application embodiment is applied to a water content determination system. Therefore, before describing the battery water content determination method provided in this application embodiment, the water content determination system used in this application embodiment will be described first.

[0127] like Figure 2 As shown, Figure 2 This is a schematic diagram of a water content determination system provided in an embodiment of this application. The water content testing system includes: a heating device 20 and an electrolytic cell 21; a sample tube 22 placed in the heating device 20 is connected to the electrolytic cell 21 through a gas pipeline 23; an electrode sample 24 built into the sample tube 22 is used to generate water vapor when the temperature of the heating device 20 reaches a first critical temperature; the gas pipeline 23 is used to transport the water vapor to the electrolytic cell 21 to obtain the water content of the electrode sample 24.

[0128] The first critical temperature is the temperature at which the cross-linked network structure formed by the cathode material and the aqueous binder in the target battery is destroyed. For example, if the target battery is a lithium-ion battery, the first critical temperature is 650°C.

[0129] The heating device 20 can be a high-temperature device, such as a slide rail furnace. The sample tube 22 is placed in the heating device 20, and the electrode sample 24 in the sample tube 22 can be heated by the heating device 20. When the heating device 20 heats the sample to the first critical temperature, the water vapor in the electrode sample 24 is completely released, and then the water vapor is transported to the electrolytic cell 21 through the gas pipeline 23 connected to the sample tube 22.

[0130] Furthermore, after receiving water vapor, the electrolytic cell 21 reacts with the electrolyte in the electrolytic cell 21. The amount of electricity generated by the water vapor during electrolysis is then measured to determine the water content of the electrode sample 24. The electrolytic cell 21 can be a Karl Fischer electrolytic cell, and the electrolyte in the electrolytic cell 21 can be a Karl Fischer reagent. When the Karl Fischer reagent reaches equilibrium, a water-containing sample is injected. The water participates in the redox reaction of iodine and sulfur dioxide. In the presence of pyridine and methanol, hydrogen, iodine, acid pyridine, and methyl pyridine sulfate are generated. The consumed iodine is generated at the anode through electrolysis, thus continuously carrying out the redox reaction until all the water is depleted. The water content is then determined based on the electrolysis produced during the electrolysis process.

[0131] Taking a lithium-ion battery as an example, at the first critical temperature, the electrode sample can destroy the cross-linked network structure formed by the cathode material and the aqueous binder in the electrode sample of the lithium-ion battery. Specifically, the cross-linked network structure formed by the cathode material and the aqueous binder is destroyed due to the gradual decomposition of the aqueous binder by heat, and the water wrapped in the cross-linked network structure is completely released.

[0132] It should be noted that the sample tube is made of a high-temperature resistant material that can withstand temperatures above the first critical temperature. For example, quartz can withstand high temperatures, so the sample tube can be made of quartz.

[0133] The water content determination system provided in this application includes a heating device and an electrolytic cell. A sample tube placed in the heating device is connected to the electrolytic cell through a gas pipeline. An electrode sample built into the sample tube is used to generate water vapor when the temperature of the heating device reaches a first critical temperature. The gas pipeline is used to transport the water vapor to the electrolytic cell to obtain the water content of the electrode sample. The first critical temperature is the temperature at which the cross-linked network structure formed by the cathode main material and the water-based binder in the target battery is destroyed. In this system, a heating device capable of reaching a first critical temperature is configured to heat the electrode sample in the sample tube to a temperature that disrupts the cross-linked network structure formed by the cathode material and the water-based binder. This disruption allows the water trapped within the cross-linked network to be completely released. In addition to the trapped water, other water in the electrode sample is also completely released at this first critical temperature. Therefore, the water content of the electrode sample is determined using the first critical temperature, assuming all water has been released, thus enabling accurate measurement. Furthermore, by connecting the sample tube to the electrolytic cell via a gas pipeline, water vapor from the sample tube is directly transported to the electrolytic cell to obtain the water content of the electrode sample, improving the speed of water content determination.

[0134] In one embodiment, such as Figure 3 As shown, the heating device 20 includes a heating pipe 31 and a heating unit 32. The heating pipe 31 has a hollow structure in the middle, and the sample tube 22 is placed in the hollow of the heating pipe 31.

[0135] The heating unit 32 is positioned directly opposite the electrode sample 24 in the sample tube 22. Figure 3 This refers to the case where the heating unit 32 is directly facing the electrode sample 24 in the sample tube 22. By positioning the heating unit directly in front of the electrode sample in the sample tube, the electrode sample is placed in the center of the heating area of ​​the heating unit, allowing the electrode sample to be fully heated and the water in the electrode sample to be completely released, thereby enabling accurate determination of the water content of the electrode sample.

[0136] The heating pipe 31 can be cylindrical, and the sample tube 22 can be a long-necked sample tube. The sample tube 22 can fit completely into the heating pipe 31, so that the sample tube 22 can be placed into the heating pipe. The sample tube can be a long straight tube or a U-shaped tube, etc.

[0137] In this embodiment, the heating pipe 31 has a hollow structure in the middle, so that the sample tube 22 is placed in the hollow structure of the heating pipe 31, and the heating unit 32 is directly opposite the electrode sample 24 in the sample tube 22. The sample tube 22 is a long-necked sample tube, so that the distance between the tube opening of the sample tube 22 and the heating unit 32 is greater than a preset distance. The heating pipe 31 can be a slide rail furnace sample tube, and the heating unit 32 can be a slide rail furnace heating system.

[0138] The following explanation uses the example of heating pipe 31 being cylindrical and sample tube 22 being U-shaped. Figure 4 As shown, the heating pipe 31 is placed horizontally, the U-shaped tube is placed horizontally in the heating pipe 31, the electrode sample 24 is placed at the bottom of the U-shaped tube, the electrode sample 24 is in the center of the heating unit 32, the heating unit 32 heats the electrode sample 24 directly, and the opening of the U-shaped tube is far away from the heating unit 32; the opening of the sample tube 22 can be sealed with a rubber stopper.

[0139] It should be noted that parameters such as the diameter and length of the sample tube and the center distance of the tube opening can be set according to the actual situation, and will not be elaborated here in the embodiments of this application.

[0140] In this embodiment, the sample tube is a long-necked sample tube, and the distance between the sample tube opening and the heating unit is greater than a preset distance; the sample tube is made of a high-temperature resistant material capable of withstanding temperatures above a first critical temperature. In this system, by setting the distance between the sample tube opening and the heating unit to be greater than a preset distance, the sample tube opening is moved away from the heating area of ​​the heating unit. For example, by making the distance between the opening of the first sample tube and the heating unit greater than a preset distance, the sample tube opening will not lose its sealing performance due to heat, thus improving the sealing performance of the sample tube and thereby improving the accuracy of determining the true water content of the battery.

[0141] In the water content determination system provided in this application embodiment, the heating device includes a heating pipe and a heating unit. The heating pipe has a hollow structure in the middle, and the sample tube is placed inside the hollow structure of the heating pipe. The heating unit is positioned directly in front of the electrode sample in the sample tube. In this system, placing the sample tube inside the hollow structure of the heating pipe allows the heating unit to heat the electrode sample. The moisture in the electrode sample can be completely evaporated under the heating of the heating unit, thereby enabling accurate determination of the water content of the electrode sample.

[0142] Since the water vapor generated in sample tube 22 needs to be output to the electrolytic cell, the water vapor can be introduced into the electrolytic cell by supplying gas to one end of the sample tube. Therefore, in one embodiment, as... Figure 5As shown, the gas pipeline 23 includes an inlet pipeline 51 and an outlet pipeline 52. The inlet of the sample tube 22 is connected to the air pump 53 through the inlet pipeline 51, and the outlet of the sample tube 22 is connected to the electrolytic cell 21 through the outlet pipeline 52. The air pump 53 is used to deliver dry gas to the sample tube 22 through the inlet pipeline 51 so as to transfer the water vapor in the sample tube 22 to the electrolytic cell 21 through the outlet pipeline 52.

[0143] Alternatively, the drying gas may be nitrogen.

[0144] After the electrode sample 24 in the sample tube 22 generates water vapor at the first critical temperature, the air pump 53 can output dry gas to the sample tube 22 through the air inlet pipe 51 at a preset flow rate, so that the water vapor in the sample tube 22 enters the electrolytic cell 21 through the air outlet pipe 52; for example, the air pump can be set to a preset flow rate of 50 ml / min.

[0145] Taking electrolytic cell 21 as an example, such as Figure 6 As shown, the Karl Fischer electrolytic cell includes a titration cup 61, an electrode 62, a Karl Fischer anodic reagent 63, and a Karl Fischer cathodic reagent 64; the outlet of the sample tube 22 is connected to the electrolytic cell 21 through an outlet pipe 52, which is essentially the outlet of the sample tube 22 being connected to the titration cup 61 of the Karl Fischer electrolytic cell through the outlet pipe 52; the water vapor in the sample tube 22 is transported to the electrolytic cell 21 through the outlet pipe 52, which is essentially the water vapor being transported to the titration cup 61 of the Karl Fischer electrolytic cell through the outlet pipe 52.

[0146] Furthermore, such as Figure 7 As shown, because the gas outlet pipe is too long and the gas outlet pipe 52 is located in the non-heating zone, a heating band 71 is wrapped around the outer ring of the gas outlet pipe 52; the heating band 71 is used to prevent water vapor in the sample tube 22 from condensing in the gas outlet pipe 52.

[0147] The heating temperature of the heating band 71 is set within a preset temperature range. For example, when measuring water content using a water content determination system, the heating temperature of the heating band 71 can be set to a preset temperature that prevents water vapor in the outlet pipe from condensing. Under the preset temperature condition, the outlet pipe 52 is heated so that the water vapor released by the electrode sample 24 will not condense in the outlet pipe, thus improving the accuracy of the measurement results.

[0148] In the water content determination system provided in this application embodiment, the gas pipeline includes an inlet pipeline and an outlet pipeline. The inlet of the sample tube is connected to an air pump through the inlet pipeline, and the outlet of the sample tube is connected to an electrolytic cell through the outlet pipeline. The air pump is used to deliver dry gas to the sample tube through the inlet pipeline to transfer water vapor in the sample tube to the electrolytic cell through the outlet pipeline. In this system, by using dry gas to vent the water vapor in the sample tube, the water vapor in the first sample tube will not increase due to the introduction of dry gas. Furthermore, the dry gas enters the sample tube through the inlet pipeline, and the water vapor in the sample tube is sent to the electrolytic cell through the outlet pipeline. By delivering dry gas and water vapor through two separate gas pipelines, all the water vapor in the sample tube can enter the electrolytic cell when the dry gas is vented into the sample tube, improving the accuracy of determining the water content in the sample tube. In addition, water vapor in the sample tube can be obtained simply by delivering dry gas to the sample tube, and the water content in the sample tube can be determined based on the water vapor, improving the convenience of determining the water content in the sample tube.

[0149] To ensure the airtightness of the entire water content determination system, in one embodiment, the air inlet pipe 51 is connected to the air inlet and the air outlet pipe 52 is connected to the air outlet through multiple adapters, and the connection of each adapter is sealed with a sealing ring.

[0150] The air intake pipe 51 is connected to the air intake port and the air outlet pipe 52 is connected to the air outlet via multiple adapters. The connection method between the air intake pipe 51 and the air intake port and the air outlet pipe 52 and the air outlet can be the same.

[0151] For example, the connection between the air inlet pipe and the air inlet of the sample tube can be as follows: the connector of the air inlet pipe is connected to one end of a reducing threaded adapter; the other end of the reducing threaded adapter is connected to one end of a threaded quick-connect adapter via a sealing ring; the other end of the threaded quick-connect adapter is connected to one end of a first rigid tube with a preset pressure bearing capacity; the other end of the first rigid tube is connected to the reducing quick-connect adapter; the other end of the reducing quick-connect adapter is connected to one end of a second rigid tube; the other end of the second rigid tube is connected to one end of an air inlet Luer needle via a Luer adapter; the other end of the air inlet Luer needle is connected to the air inlet of the sample tube; and the other end of the air inlet pipe is connected to an air pump.

[0152] Accordingly, the connection between the gas outlet pipeline and the gas outlet can be as follows: the connector of the gas outlet pipeline is connected to one end of a reducing threaded adapter; the other end of the reducing threaded adapter is connected to one end of a threaded quick-connect adapter via a sealing ring; the other end of the threaded quick-connect adapter is connected to one end of a first rigid tube with a preset pressure bearing capacity; the other end of the first rigid tube is connected to the reducing quick-connect adapter; the other end of the reducing quick-connect adapter is connected to one end of a second rigid tube; the other end of the second rigid tube is connected to one end of a gas outlet Luer needle via a Luer adapter; the other end of the gas outlet Luer needle is connected to the gas outlet of the sample tube; and the other end of the gas outlet pipeline is connected to the electrolytic cell.

[0153] The connection method between the air inlet and the air inlet of the sample tube will be explained, such as... Figure 8 As shown, a1 is the inlet pipe connector, a2 is the reducing threaded adapter, a3 is the threaded to quick-connect adapter, a4 is the first rigid tube, a5 is the reducing quick-connect adapter, a6 is the second rigid tube, a7 is the Luer adapter, and a8 is the inlet Luer needle. The inlet pipe connector has an external thread interface, the reducing threaded adapter has an internal thread to external thread interface, the threaded to quick-connect adapter has an internal thread to quick-connect interface, the first rigid tube connects the threaded to quick-connect adapter and the reducing quick-connect adapter, the reducing quick-connect adapter has a quick-connect to quick-connect interface, and the second rigid tube connects the reducing quick-connect adapter and the Luer adapter. The connection between the reducing threaded adapter and the threaded to quick-connect adapter is sealed with a sealing ring to ensure airtightness. The inlet Luer needle is inserted into the inlet of the sample tube.

[0154] In the water content determination system provided in this application embodiment, the inlet pipe and the outlet pipe are connected by multiple adapters, and the connection points of each adapter are sealed with sealing rings. By using multiple adapters to connect the inlet pipe and the outlet pipe to the outlet, and sealing the connection points of each adapter with sealing rings, the sealing performance between the inlet pipe and the sample tube's inlet, and between the outlet pipe and the sample tube's outlet, is improved. This enhances the overall sealing performance of the water content determination system and thus improves the accuracy of battery water content determination.

[0155] It is understood that the design of each structure in the water content determination system in the above embodiments is only one example of achieving the technical effect of this application. In practical applications, it can also be adapted to achieve easily conceivable technical effects. The embodiments of this application do not limit its structure.

[0156] Next, the battery water content determination method provided in the embodiments of this application will be described. The battery water content determination methods in the embodiments of this application are all applied to the above-mentioned... Figure 2 The water content measurement system in the middle.

[0157] In one embodiment, such as Figure 9 As shown, this embodiment includes the following steps:

[0158] S101, perform moisture determination on the electrode sample of the target battery according to the first critical temperature to obtain the water content of the electrode sample; the first critical temperature is the temperature at which the cross-linked network structure formed by the cathode main material and the water-based binder in the target battery is destroyed.

[0159] Before performing moisture determination on the electrode sample of the target battery according to the first critical temperature, it is necessary to obtain the electrode sample of the target battery. In one embodiment, the electrode sample of the target battery can be obtained by cutting the battery electrode in the target battery after the target battery has been baked. The electrode sample is a sheet-like electrode of a preset size.

[0160] Specifically, the target battery after baking is obtained, and then the battery electrode sheet of the target battery is obtained and cut. First, the edge part of the battery electrode sheet is cut off, and the remaining part of the battery electrode sheet is cut into sheet-like electrode sheets according to the preset size. The battery electrode sheet can be cut with ceramic scissors. The preset size can be 1cm*1cm, but this application is not limited to this and the specific size can be set according to the specific scenario.

[0161] After cutting the remaining part of the battery electrode into sheet-like electrodes, a sheet-like electrode of a preset weight is obtained as an electrode sample; optionally, the preset weight can be 0.6 to 1.2g, which is not limited in this application and can be set according to the specific scenario.

[0162] After the electrode sample is prepared, the moisture content of the electrode sample is determined under the condition of the first critical temperature. Specifically, the electrode sample is heated to the first critical temperature, and then the water vapor evaporated from the electrode sample at the first critical temperature is obtained. Then, the water vapor is electrolyzed with the electrolyte in the electrolytic cell, and the water content of the electrode sample is determined based on the amount of electricity generated during the electrolysis process.

[0163] S102, determine the water content of the target battery based on the water content of the electrode sample.

[0164] The water content of the electrode sample obtained above is actually the absolute water content of the electrode sample. In practical applications, it is necessary to determine the water content of the target battery based on the absolute water content of the electrode sample. The water content of the target battery is the relative water content.

[0165] One way to determine the water content of the target battery is to obtain the mass of an electrode sample and determine the ratio of the absolute water content of the electrode sample to the mass of the electrode sample as the relative water content of the target battery. The relative water content of the target battery is the water content of the target battery in this embodiment of the application.

[0166] In the battery water content determination method provided in this application embodiment, the water content of the electrode sample of the target battery is determined by performing a water content determination on the electrode sample according to a first critical temperature. Then, the water content of the target battery is determined based on the water content of the electrode sample. The first critical temperature is the temperature at which the cross-linked network structure formed by the cathode main material and the aqueous binder in the target battery is destroyed. In this method, the electrode sample of the target battery is heated to the first critical temperature that can destroy the cross-linked network structure formed by the cathode main material and the aqueous binder in the target battery. This causes the cross-linked network structure formed by the cathode main material and the aqueous binder in the target battery to be destroyed. The destruction of the cross-linked network structure allows the water trapped in the cross-linked network structure in the electrode sample to be completely released. In addition to the trapped water, other water in the electrode sample can also be completely released at this first critical temperature. Thus, it is equivalent to using the first critical temperature to determine the water content of the electrode sample. The determination is performed when all the water in the electrode sample has been completely released, thereby accurately determining the water content in the electrode sample. Furthermore, since the electrode sample is part of the target battery, the water content of the target battery can be accurately characterized by the water content in the electrode sample, provided that the water content in the electrode sample is accurately determined.

[0167] The water content of the electrode sample includes the actual water content of the electrode sample, that is, all the water content in the electrode sample. In one embodiment, such as... Figure 10 As shown, the moisture content of the electrode sample of the target battery is determined by performing a moisture determination based on the first critical temperature, including the following steps:

[0168] S201, when the heating device is heated to the first critical temperature, the first sample tube containing the electrode sample is placed into the heating device to obtain the water content in the first sample tube.

[0169] Before performing moisture determination on the electrode sample of the target battery, the electrode sample needs to be placed in a first sample tube. The process of placing the electrode sample in the first sample tube includes: placing the cleaned empty tube into an oven in a drying room and drying it for a preset time; then taking out the dried empty tube and placing it on a clean sample preparation table for later use; loading the prepared electrode sample into the empty tube; sealing the opening of the empty tube with a rubber stopper; covering it with an aluminum cap and sealing it with sealing pliers to obtain the prepared first sample tube containing the electrode sample; for example, the preset time can be 4 to 8 hours, which is not limited in this application and can be set according to the actual situation.

[0170] After the first sample tube is prepared, the heating device is controlled to heat to the first critical temperature. When the heating device is heated to the first critical temperature, the first sample tube containing the electrode sample is placed into the heating device. When the electrode sample is at the first critical temperature, the cross-linked network structure formed by the cathode material and the water-based binder in the electrode sample is destroyed, and the water in the electrode sample is completely evaporated in the first sample tube. Then, the water content in the first sample tube is determined based on the water vapor in the first sample tube.

[0171] It should be noted that the electrode sample preparation process and the sample tube preparation process in the embodiments of this application are both carried out in a drying room.

[0172] S202, based on the water content in the first sample tube, obtain the true water content of the electrode sample.

[0173] Due to environmental factors, the first sample tube may contain a certain amount of moisture. Therefore, the water content in the first sample tube obtained above includes not only the water content of the electrode sample but also the water content of the first sample tube itself. Therefore, to obtain the true water content of the electrode sample, it is necessary to obtain the water content in an empty sample tube without an electrode sample to determine the true water content of the electrode sample.

[0174] In one embodiment, such as Figure 11 As shown, the true water content of the electrode sample is obtained based on the water content in the first sample tube, including the following steps:

[0175] S301, Obtain the water content in the empty sample tube; no electrode sample is placed in the empty sample tube.

[0176] Since the water content in the empty sample tube is the same as the water content in the air inside the empty sample tube, the water content in the empty sample tube can be obtained at any temperature that allows the moisture in the air inside the empty sample tube to evaporate.

[0177] For example, taking the first critical temperature as an example, when the heating device is heated to the first critical temperature, an empty sample tube is placed in the heating device to obtain the water content of the empty sample tube.

[0178] S302, determine the true water content of the electrode sample based on the water content of the empty sample and the water content in the first sample tube.

[0179] The water content of the empty sample is the water content in the empty sample tube, and the water content in the first sample tube is the water content of the electrode sample and the water content in the first sample tube. Therefore, the difference between the water content in the first sample tube and the water content of the empty sample is determined as the true water content of the electrode sample.

[0180] In this embodiment, since there may be a certain amount of moisture in the environment of the first sample tube before the electrode sample is placed, the water content in the first sample tube actually includes the water content in the environment of the first sample tube and the water content of the electrode sample. Therefore, when determining the true water content of the electrode sample, it is necessary to consider the empty sample water content in the empty sample tube without the electrode sample, and then remove the empty sample water content from the water content in the first sample tube to obtain the true water content of the electrode sample, thereby improving the accuracy of the measured true water content of the electrode sample.

[0181] In the battery water content determination method provided in this application embodiment, after heating the heating device to a first critical temperature, a first sample tube containing an electrode sample is placed into the heating device to obtain the water content in the first sample tube, and the true water content of the electrode sample is obtained based on the water content in the first sample tube. In this method, by configuring a heating device capable of heating to the first critical temperature to heat the first sample tube containing the electrode sample, the electrode sample in the first sample tube can be heated to the first critical temperature, thereby accurately obtaining the water content in the first sample tube. Furthermore, by placing the first sample tube into the heating device after heating to the first critical temperature, the heating device is essentially placed in a stable heating state, ensuring that the first sample tube is heated stably after being placed in the heating device, thus enabling rapid acquisition of the water content in the first sample tube. Since the first sample tube includes the electrode sample, the water content in the first sample tube includes the water content in the electrode sample; therefore, the true water content of the electrode sample can be accurately obtained based on the water content in the first sample tube.

[0182] In one embodiment, the heating device includes a heating pipe and a heating unit, wherein the heating pipe has a cavity structure in the middle; when the heating device is heated to a first critical temperature, a first sample tube containing an electrode sample is placed into the heating device, including: when the heating pipe is heated to the first critical temperature by the heating unit, the first sample tube is placed into the cavity of the heating pipe.

[0183] Please continue to refer to this. Figure 3 The first sample tube is placed into the heating device, which is essentially placing the first sample tube into the cavity of the heating pipe.

[0184] The heating unit is positioned directly above the electrode sample in the first sample tube, which is located at the bottom of the first sample tube.

[0185] When the heating unit heats the heating pipe to the first critical temperature, the first sample tube is placed into the cavity of the heating pipe, and the heating unit is positioned directly in front of the electrode sample in the first sample tube. This ensures that the electrode sample is in the center of the heating area of ​​the heating unit, allowing the electrode sample to be fully heated and the moisture in the electrode sample to be completely released, thereby enabling accurate determination of the water content of the electrode sample.

[0186] In the battery water content determination method provided in this application embodiment, the heating device includes a heating pipe and a heating unit. The heating pipe has a hollow cavity structure in the middle. After the heating pipe is heated to a first critical temperature by the heating unit, a first sample tube is placed into the cavity of the heating pipe. In this method, the heating pipe is heated to the first critical temperature before the first sample tube is placed into the cavity of the heating pipe. This is equivalent to first placing the heating pipe in a heated and stable state, so that the first sample tube is heated and stabilized after being placed in the heating pipe, thereby enabling rapid acquisition of the water content in the first sample tube.

[0187] In one embodiment, the first sample tube is a long-necked sample tube, and the distance between the opening of the long-necked sample tube and the heating unit is greater than a preset distance.

[0188] The first sample tube is a long-necked sample tube, and the opening of the long-necked sample tube is far away from the heating area of ​​the heating unit. Therefore, the distance between the opening of the long-necked sample tube and the heating area of ​​the heating unit is greater than the preset distance.

[0189] In the battery water content determination method provided in this application embodiment, the sample tube is a long-necked sample tube, and the distance between the opening of the sample tube and the heating unit is greater than a preset distance. In this system, by setting the distance between the opening of the first sample tube and the heating unit to be greater than the preset distance, the opening of the first sample tube is moved away from the heating area of ​​the heating unit. For example, by making the distance between the opening of the first sample tube and the heating unit greater than the preset distance, the opening of the first sample tube will not lose its sealing performance due to heat, thus improving the sealing performance of the first sample tube and thereby improving the accuracy of determining the true water content of the battery.

[0190] In one embodiment, the first sample tube includes an inlet and an outlet; the inlet is connected to an inlet pipe, and the outlet is connected to an electrolytic cell through an outlet pipe; obtaining the water content in the first sample tube includes: when dry gas enters the first sample tube through the inlet pipe and water vapor generated by heating the electrode sample is sent into the electrolytic cell through the outlet pipe, determining the water content in the first sample tube based on the amount of electricity generated during the electrolysis process of the water vapor in the electrolytic cell.

[0191] The first sample tube includes two ports: an inlet and an outlet. The inlet is connected to an inlet pipe, the other end of which is connected to an air pump. The outlet is connected to an electrolytic cell via an outlet pipe. When the heating unit heats the sample to the first critical temperature, the first sample tube is placed in the heating pipe. The electrode sample in the first sample tube is heated, causing the moisture in the electrode sample to evaporate. Then, the air pump delivers dry gas to the first sample tube through the inlet pipe at a preset flow rate. The water vapor generated in the first sample tube is then transferred to the electrolytic cell through the outlet pipe. The water vapor can then electrolyze with the electrolyte in the electrolytic cell. The water content in the first sample tube is determined based on the amount of electricity generated by the water vapor during the electrolysis process.

[0192] In the battery water content determination method provided in this application embodiment, the first sample tube includes an inlet and an outlet. The inlet is connected to an inlet pipe, and the outlet is connected to the electrolytic cell through an outlet pipe. When dry gas enters the first sample tube through the inlet pipe and water vapor generated by heating the electrode sample is sent into the electrolytic cell through the outlet pipe, the water content in the first sample tube is determined based on the amount of electricity generated by the electrolysis process of the water vapor in the electrolytic cell. In this method, water vapor in the first sample tube is vented using a dry gas, preventing an increase in water vapor in the first sample tube due to the introduction of dry gas. Furthermore, the dry gas enters the first sample tube through an inlet pipe, while water vapor generated by the electrode sample is sent to the electrolytic cell through an outlet pipe. By transporting the dry gas and water vapor through two separate gas pipes, all water vapor in the first sample tube can enter the electrolytic cell while the dry gas is being vented into the first sample tube, thus improving the accuracy of determining the water content in the first sample tube. In addition, water vapor in the first sample tube can be obtained simply by supplying dry gas to the first sample tube, allowing the determination of the water content in the first sample tube based on the water vapor content, thereby improving the convenience of determining the water content in the first sample tube.

[0193] The above embodiments illustrate how to obtain the true water content of electrode samples. However, water content also includes water in different bound forms: free water and bound water. The following embodiment illustrates how to obtain the free water content and bound water content of electrode samples. In one embodiment, as shown... Figure 12 As shown, the water content includes free water content and bound water content. The water content of the electrode sample of the target battery is obtained by performing a moisture determination on the sample based on the first critical temperature, including:

[0194] S401, perform moisture determination on the second sample tube containing the electrode sample according to the second critical temperature to obtain the free water content of the electrode sample.

[0195] The second critical temperature is the temperature at which the free water in the electrode sample can be completely released; the second critical temperature is lower than the first critical temperature, for example, the second critical temperature can be 170℃.

[0196] Free water in the electrode sample at the second critical temperature can be released, and bound water in the electrode sample at the first critical temperature can be released. Therefore, when obtaining the free water content and bound water content of the electrode sample respectively, the free water content of the electrode sample is obtained first. After the free water in the electrode sample is released, the remaining water in the electrode sample is divided into bound water content, and then the bound water content in the electrode sample is obtained.

[0197] Therefore, after preparing the second sample tube containing the electrode sample, a moisture determination is performed on the second sample tube according to the second critical temperature to obtain the free water content of the electrode sample. The method for preparing the second sample tube is the same as that for preparing the first sample tube described above, and will not be repeated here.

[0198] After the second sample tube is prepared, moisture determination is performed on the second sample tube under the condition of the second critical temperature to obtain the free water content of the electrode sample. Specifically, the second sample tube is heated to the second critical temperature, and then the water vapor evaporated from the electrode sample in the second sample tube at the second critical temperature is obtained. Then, the water vapor is electrolyzed with the electrolyte in the electrolytic cell, and the free water content of the electrode sample is determined according to the amount of electricity generated during the electrolysis process.

[0199] S402, after the free water content of the electrode sample is determined, the moisture content of the second sample tube is determined according to the first critical temperature to obtain the bound water content of the electrode sample.

[0200] After the free water content of the electrode sample is determined, the moisture content of the second sample tube is determined according to the first critical temperature to obtain the bound water content of the electrode sample. Specifically, after the free water content of the electrode sample is determined, the second sample tube is heated to the first critical temperature, and then the water vapor evaporated from the electrode sample in the second sample tube at the first critical temperature is obtained. Then, the water vapor is electrolyzed with the electrolyte in the electrolytic cell, and the bound water content of the electrode sample is determined according to the amount of electricity generated during the electrolysis process.

[0201] It should be noted that the sum of the free water content and the bound water content in the electrode sample is equal to the actual water content of the electrode sample.

[0202] In the battery water content determination method provided in this application embodiment, a water content determination is performed on a second sample tube containing an electrode sample according to a second critical temperature to obtain the free water content of the electrode sample; the second critical temperature is lower than the first critical temperature; after the free water content determination of the electrode sample is completed, a water content determination is performed on the second sample tube according to the first critical temperature to obtain the bound water content of the electrode sample. In this method, by performing water content determination at different critical temperatures, the free water content and bound water content of the electrode sample are obtained. By identifying water content in different bound forms through different critical temperatures, all forms of water content in the electrode sample can be comprehensively released, ensuring that the water content in any form can be effectively and accurately determined.

[0203] The specific process for obtaining the free water content of electrode samples is described in detail below. In one embodiment, such as... Figure 13 As shown, the moisture content of the electrode sample is determined by performing a moisture determination on the second sample tube containing the electrode sample at the second critical temperature, including the following steps:

[0204] S501, when the heating device is heated to the second critical temperature, the second sample tube containing the electrode sample is placed into the heating device to obtain the water content in the second sample tube.

[0205] When obtaining the water content in the second sample tube, the heating device is heated to the second critical temperature. When the heating device is heated to the second critical temperature, the second sample tube containing the electrode sample is placed into the heating device. When the electrode sample reaches the second critical temperature, the free water in the electrode sample is released and water vapor is generated. Then, the water content in the second sample tube is determined based on the water vapor generated in the second sample tube.

[0206] It should be noted that the method of determining the water content in the second sample tube based on the water vapor generated in the second sample tube is the same as the method of determining the water content in the first sample tube based on the water vapor in the first sample tube, and will not be repeated here in the embodiments of this application.

[0207] Based on the above embodiments, it can be seen that the heating device includes a heating pipe and a heating unit, and the heating pipe has a hollow structure in the middle. Therefore, when the heating device is heated to the second critical temperature, the second sample tube containing the electrode sample is placed into the heating device, which includes: heating the heating pipe to the second critical temperature by the heating unit, and then placing the second sample tube into the hollow of the heating pipe; wherein, the heating unit is directly facing the electrode sample in the second sample tube, the second sample tube is a long-necked sample tube, and the distance between the opening of the long-necked sample tube and the heating unit is greater than a preset distance.

[0208] Furthermore, the second sample tube includes an inlet and an outlet; the inlet is connected to an inlet pipe, and the outlet is connected to the electrolytic cell through an outlet pipe. Therefore, obtaining the water content in the second sample tube includes: when the drying gas enters the second sample tube through the inlet pipe, and the water vapor generated by heating the electrode sample is sent into the electrolytic cell through the outlet pipe, the water content in the second sample tube is determined based on the amount of electricity generated during the electrolysis process of the water vapor in the electrolytic cell.

[0209] S502, determine the free water content of the electrode sample based on the water content in the second sample tube.

[0210] Due to environmental factors, the second sample tube may contain a certain amount of moisture. Therefore, the water content in the second sample tube obtained above includes not only the free water content of the electrode sample but also the water content in the second sample tube itself. Therefore, to obtain the free water content of the electrode sample, it is necessary to obtain the water content in an empty sample tube without an electrode sample to determine the free water content of the electrode sample.

[0211] Therefore, in one embodiment, such as Figure 14 As shown, the free water content of the electrode sample is determined based on the water content in the second sample tube, including the following steps:

[0212] S601, Obtain the water content in the empty sample tube; no electrode sample is placed in the empty sample tube.

[0213] S602, determine the free water content of the electrode sample based on the water content of the empty sample and the water content in the second sample tube.

[0214] One way to obtain the water content in the empty sample tube is to place the empty sample tube into the heating device when the heating device is heated to the second critical temperature, and then obtain the water content in the empty sample tube.

[0215] The difference between the water content in the second sample tube and the water content in the empty sample tube is then determined as the free water content of the electrode sample.

[0216] In this embodiment, since there may be some moisture in the environment of the second sample tube before the electrode sample is placed, the water content in the second sample tube actually includes the water content in the environment of the second sample tube and the free water content of the electrode sample. Therefore, when determining the free water content of the electrode sample, it is necessary to consider the empty sample water content in the empty sample tube without the electrode sample, and then remove the empty sample water content from the water content in the second sample tube to obtain the free water content of the electrode sample, thereby improving the accuracy of the measured free water content of the electrode sample.

[0217] In the battery water content determination method provided in this application embodiment, a second sample tube containing an electrode sample is placed into the heating device after heating the heating device to a second critical temperature, and the water content in the second sample tube is obtained; based on the water content in the second sample tube, the free water content of the electrode sample is determined. In this method, the second critical temperature allows the free water in the electrode sample to be completely released; therefore, the water content in the second sample tube can be accurately obtained at the second critical temperature. Furthermore, the water content in the second sample tube includes the free water content of the electrode sample; therefore, based on the water content in the second sample tube, the free water content of the electrode sample can be accurately obtained.

[0218] The specific process for obtaining the bound water content of the electrode sample is described in detail below. In one embodiment, the bound water content of the electrode sample is obtained by performing a moisture determination on the second sample tube according to the first critical temperature, including: removing the second sample tube from the heating device, and then placing the second sample tube back into the heating device while heating the heating device to the first critical temperature to obtain the bound water content of the electrode sample.

[0219] When the heating device is heated to the second critical temperature, a second sample tube containing the electrode sample is placed into the heating device. After obtaining the water content in the second sample tube, it is removed from the heating device. The heating device is then heated again until it reaches the first critical temperature. The second sample tube is then placed back into the heating device. At the first critical temperature, the bound water in the electrode sample in the second sample tube is completely released, generating water vapor. The water content in the second sample tube is then determined based on the water vapor generated. At this point, the water content in the second sample tube is the bound water content of the electrode sample.

[0220] Since the free water content of the electrode sample was obtained at the second critical temperature before obtaining the bound water content of the electrode sample in the second sample tube, the water carried in the second sample tube itself had already evaporated when the free water content of the electrode sample was obtained. Therefore, the water content in the second sample tube obtained at the first critical temperature is the bound water content of the electrode sample.

[0221] In one embodiment, removing the second sample tube from the heating device and then placing the second sample tube back into the heating device after heating the heating device to a first critical temperature includes: removing the second sample tube from the heating pipe and placing the second sample tube back into the heating pipe after heating the heating unit to the first critical temperature.

[0222] Obtaining the bound water content of the electrode sample involves: with dry gas entering the second sample tube through the inlet pipe and water vapor generated by heating the electrode sample being sent into the electrolytic cell through the outlet pipe, the bound water content of the electrode sample is determined based on the amount of electricity generated during the electrolysis process of the water vapor in the electrolytic cell.

[0223] In the battery water content determination method provided in this application embodiment, a second sample tube is removed from the heating device, and after the heating device is heated to a first critical temperature, the second sample tube is placed back into the heating device to obtain the bound water content of the electrode sample. In this method, the step of placing the second sample tube into the heating device to obtain the bound water content of the electrode sample is performed after determining the free water content of the electrode sample in the second sample tube. At this time, the free water of the electrode sample in the second sample tube has been completely evaporated, leaving only the bound water that has not evaporated at the second critical temperature. Therefore, by placing the second sample tube back into the heating device to perform water content determination after heating the device to the first critical temperature, the bound water content of the electrode sample can be accurately obtained.

[0224] Before performing moisture determination using a water content determination system, the drift value in the water content determination system needs to be stabilized below a preset value. Therefore, in one embodiment, before performing moisture determination, the embodiment includes controlling the drift value in the gas measurement environment to be less than a preset drift threshold by using a drift stabilization empty sample tube.

[0225] When determining the water content of a battery using a water content determination system, the drift value in the system is unstable. Therefore, before performing the water content determination, it is necessary to stabilize the drift value in the system. Thus, a drift-stabilized empty sample tube needs to be prepared.

[0226] When performing moisture determination on the electrode sample of the target battery according to the first critical temperature, when the heating device heats to the first critical temperature, the drift stabilization empty sample tube is placed into the heating pipe of the heating device. After the drift value in the gas measurement environment is controlled to be less than the preset drift threshold by the drift stabilization empty sample tube, the drift stabilization empty sample tube is taken out from the heating device, and then the moisture content of the electrode sample of the target battery is determined.

[0227] Before obtaining the water content in the empty sample tube, it is necessary to ensure that the drift value in the control gas measurement environment of the drift-stabilized empty sample tube is less than the preset drift threshold before performing moisture measurement on the empty sample tube.

[0228] To obtain the free water content and bound water content of the electrode sample, the heating device is heated to the second critical temperature. Then, the drift value in the gas measurement environment is controlled to be less than the preset drift threshold by using a drift stabilizing empty sample tube. Next, the moisture content of the second sample tube containing the electrode sample is measured to obtain the free water content of the electrode sample. After the free water content of the electrode sample is measured, the second sample tube is removed from the heating device. While the heating device is heated to the first critical temperature, the drift stabilizing empty sample tube is placed into the heating device. After the drift value in the gas measurement environment is controlled to be less than the preset drift threshold by using the drift stabilizing empty sample tube, the second sample tube is put back into the heating device to obtain the bound water content of the electrode sample.

[0229] To maximize the accuracy of determining the water content of electrode samples, a small preset drift threshold can be set, for example, 5 ppm. This application does not limit this setting and the threshold can be adjusted according to the actual situation.

[0230] In the battery water content determination method provided in this application embodiment, before performing the water content determination, the drift value in the gas measurement environment is controlled to be less than a preset drift threshold by using a drift stabilizing empty sample tube. In this method, before each water content determination, in order to remove other interfering factors in the gas measurement environment, such as moisture and incomplete sealing, it is necessary to control the drift value in the gas measurement environment to be stable below the preset drift threshold, so that subsequent water content determination operations are carried out in a completely undisturbed environment, improving the accuracy of the water content determination results. Furthermore, by using a drift stabilizing empty sample tube to stabilize the drift value in the water content determination system below the preset drift threshold, the speed of determining the battery water content is increased.

[0231] To assess the reliability of determining the water content in batteries, the reliability of the water content determination system can be verified. Specifically, the airtightness, feasibility, and testing capability of the Karl Fischer coulomb trace moisture analyzer and the water content determination system provided in this application are evaluated to verify the accuracy of the water content determination system provided in this application.

[0232] The airtightness of the water content determination system provided in this application was evaluated by testing the moisture content of a solid water standard using both a Karl Fischer coulomb trace moisture analyzer and the water content determination system provided in this application. Taking a solid standard substance with a moisture content of 10,000 ppm as an example, assuming the test result error is within ±200 ppm, the airtightness of the measurement system can be considered to meet the requirements. Figure 15 As shown, Figure 15 (a) shows the airtightness test results of the Karl Fischer coulomb trace moisture analyzer. Figure 15(b) The airtightness test results of the water content determination system provided in this application, wherein the horizontal axis is the sample number and the vertical axis is the water content. According to the test results, the airtightness of the water content determination system provided in this application meets the requirements.

[0233] Samples of the same type of electrode were prepared, and the test results of the electrode were compared and verified by the Karl Fischer coulomb trace moisture analyzer and the water content determination system provided in this application. If the verification was successful, the water content determination system provided in this application was considered feasible.

[0234] Selected electrodes of the same type were tested under certain temperature conditions using a Karl Fischer coulomb trace moisture analyzer and the water content determination system provided in this application. If the repeatability and reproducibility verification passed, the testing capability of the water content determination system provided in this application was considered to meet the requirements. Figure 16 As shown, Figure 16 (a) shows the repeatability test results of the Karl Fischer coulomb trace moisture analyzer. Figure 16 (b) The repeatability test results of the water content determination system provided in this application, wherein the horizontal axis represents the sample number and the vertical axis represents the water content.

[0235] like Figure 17 As shown, Figure 17 The box plot is generated based on the test verification data of the Karl Fischer coulomb trace moisture analyzer and the water content determination system provided in this application. System 1 represents the Karl Fischer coulomb trace moisture analyzer, and System 2 represents the water content determination system. As can be seen from the figure, the water content determination system provided in this application has passed the verification.

[0236] The electrode sheets baked on the production line were tested with a Karl Fischer coulomb trace moisture analyzer under certain temperature conditions. The test results showed that there was no significant difference in the water content of the electrode sheets in the same batch and different batches. However, when these electrode sheets were made into battery cells and their performance was tested, there were significant differences in the test results (or the water content of the electrode sheets was different, but the performance of the battery cells was the same).

[0237] Therefore, characterizing the water content of a battery by measuring its water content using a water content determination system and correlating the test results with the performance of the downstream battery cells enables rapid prediction of cell performance. Furthermore, by preparing electrodes from raw materials using different manufacturing processes and testing their true water content after baking, the most suitable raw material processing technology can be selected based on the test results. This can be used solely for rapidly predicting various performance characteristics of the finished battery cells and guiding process improvements.

[0238] In one embodiment, this application also provides a method for determining the water content of a battery, such as... Figure 18As shown, it should be noted that all parameter values ​​used in this embodiment are examples and are not limited to these data in actual applications. This embodiment includes the following steps:

[0239] S701, after baking, remove the electrode from the battery, cut off the edge of the electrode with ceramic scissors, and cut the remaining part into sheet-like electrode. Weigh the sheet-like electrode of the preset weight using a balance as an electrode sample, and prepare two electrode samples.

[0240] S702, two electrode samples are loaded into sample tubes to obtain the first sample tube and the second sample tube, and then an empty sample tube and a drift-stabilized empty sample tube are prepared.

[0241] S703 controls the water content measurement system to start, the heating unit to heat up to the second critical temperature and maintain a constant temperature, the heating belt to heat at the preset temperature, and the air pump to turn on and set the flow rate to the preset flow rate.

[0242] S704, insert the inlet Luer needle of the inlet pipe and the outlet Luer needle of the outlet pipe into the inlet and outlet of the drift stabilization empty sample tube, respectively. After waiting for the drift value to stabilize below the preset drift threshold, pull out the inlet and outlet needles and insert them into the empty sample tube. Place the empty sample tube into the heating unit for empty sample measurement to obtain the water content of the empty sample.

[0243] S705, after the empty sample measurement is completed, the inlet and outlet needles are pulled out of the empty sample tube and inserted into the drift stabilization empty sample tube. The drift stabilization empty sample tube is placed in the heating pipe. After waiting for the drift value to stabilize below the preset drift threshold, the inlet and outlet needles are pulled out and inserted into the second sample tube. The second sample tube is placed in the heating pipe to measure the water content of the second sample tube and obtain the free water content in the second sample tube.

[0244] S706, the difference between the free water content in the second sample tube and the water content of the empty sample is the free water content of the electrode sample.

[0245] S707, remove the second sample tube from the heating pipe and turn off the air pump. After heating the heating unit to the first critical temperature, turn on the air pump. Insert the inlet Luer needle of the inlet pipe and the outlet Luer needle of the outlet pipe into the inlet and outlet of the drift stabilization empty sample tube, respectively. After waiting for the drift value to stabilize below the preset drift threshold, put the second sample tube back into the heating pipe to determine the water content of the second sample tube. The test value is the bound water content of the electrode sample.

[0246] S708. After the test is completed, the inlet and outlet needles are pulled out of the second sample tube and inserted into the drift stabilization empty sample tube. After the drift value stabilizes below the preset drift threshold, the inlet and outlet needles are pulled out and inserted into the first sample tube. The first sample tube is placed in the heating pipe to determine the water content of the sample and obtain the water content in the first sample tube.

[0247] S709, the difference between the water content in the first sample tube and the water content of the empty sample is determined as the true water content of the electrode sample.

[0248] It should be understood that although the steps in the flowcharts of the embodiments described above are shown sequentially according to the arrows, these steps are not necessarily executed in the order indicated by the arrows. Unless explicitly stated herein, there is no strict order restriction on the execution of these steps, and they can be executed in other orders. Moreover, at least some steps in the flowcharts of the embodiments described above may include multiple steps or multiple stages. These steps or stages are not necessarily completed at the same time, but can be executed at different times. The execution order of these steps or stages is not necessarily sequential, but can be performed alternately or in turn with other steps or at least some of the steps or stages of other steps.

[0249] Based on the same inventive concept, this application also provides a battery water content measuring device for implementing the battery water content measuring method described above. The solution provided by this device is similar to the solution described in the above method; therefore, the specific limitations in one or more battery water content measuring device embodiments provided below can be found in the limitations of the battery water content measuring method described above, and will not be repeated here.

[0250] In one embodiment, such as Figure 19 As shown, a battery water content measuring device 1900 is provided, including: an acquisition module 1901 and a determination module 1902, wherein:

[0251] The acquisition module 1901 is used to perform moisture determination on the electrode sample of the target battery according to the first critical temperature to obtain the water content of the electrode sample; the first critical temperature is the temperature at which the cross-linked network structure formed by the cathode main material and the water-based binder in the target battery is destroyed;

[0252] The determination module 1902 is used to determine the water content of the target battery based on the water content of the electrode sample.

[0253] In one embodiment, the acquisition module 1901 includes:

[0254] The first acquisition unit is used to place a first sample tube containing an electrode sample into the heating device when the heating device is heated to a first critical temperature, and to acquire the water content in the first sample tube.

[0255] The second acquisition unit is used to acquire the true water content of the electrode sample based on the water content in the first sample tube.

[0256] In one embodiment, the second acquisition unit includes:

[0257] The first acquisition subunit is used to acquire the water content of the empty sample tube; no electrode sample is placed in the empty sample tube.

[0258] The first determining subunit is used to determine the true water content of the electrode sample based on the water content of the empty sample and the water content in the first sample tube.

[0259] In one embodiment, the first acquisition unit includes:

[0260] A heating unit is used to place a first sample tube into the cavity of the heating pipe when the heating pipe is heated to a first critical temperature by the heating unit; wherein the heating unit is directly facing the electrode sample in the first sample tube.

[0261] In one embodiment, the first sample tube is a long-necked sample tube, and the distance between the opening of the long-necked sample tube and the heating unit is greater than a preset distance.

[0262] In one embodiment, the first acquisition unit includes:

[0263] The second determining subunit is used to determine the water content in the first sample tube based on the amount of electricity generated during the electrolysis process of the water vapor in the electrolytic cell, when the dry gas enters the first sample tube through the inlet pipe and the water vapor generated by heating the electrode sample is sent into the electrolytic cell through the outlet pipe.

[0264] In one embodiment, the acquisition module 1901 includes:

[0265] The third acquisition unit is used to perform moisture determination on the second sample tube containing the electrode sample according to the second critical temperature to obtain the free water content of the electrode sample; the second critical temperature is lower than the first critical temperature;

[0266] The fourth acquisition unit is used to perform moisture determination on the second sample tube according to the first critical temperature after the free water content of the electrode sample is determined, so as to obtain the bound water content of the electrode sample.

[0267] In one embodiment, the third acquisition unit includes:

[0268] The second acquisition subunit is used to place the second sample tube containing the electrode sample into the heating device when the heating device is heated to the second critical temperature, and to acquire the water content in the second sample tube.

[0269] The third determining subunit is used to determine the free water content of the electrode sample based on the water content in the second sample tube.

[0270] In one embodiment, the third determining subunit includes:

[0271] The third acquisition subunit is used to acquire the water content of the empty sample tube; no electrode sample is placed in the empty sample tube.

[0272] The fourth determining subunit is used to determine the free water content of the electrode sample based on the water content of the empty sample and the water content in the second sample tube.

[0273] In one embodiment, the fourth acquisition unit includes:

[0274] The fourth acquisition subunit is used to remove the second sample tube from the heating device, and then put the second sample tube back into the heating device after heating the heating device to the first critical temperature to obtain the bound water content of the electrode sample.

[0275] In one embodiment, the device 1900 further includes:

[0276] The control module is used to control the drift value in the gas measurement environment to be less than a preset drift threshold by using a drift stabilization empty sample tube.

[0277] In one embodiment, the device 1900 further includes:

[0278] The preparation module is used to cut the battery electrode sheets in the target battery after the target battery has been baked to obtain the electrode sheet sample of the target battery; the electrode sheet sample is a sheet-like electrode sheet of a preset size.

[0279] Each module in the aforementioned battery water content measuring device can be implemented entirely or partially through software, hardware, or a combination thereof. These modules can be embedded in or independent of the processor in a computer device, or stored in the computer device's memory as software, so that the processor can call and execute the corresponding operations of each module.

[0280] In one embodiment, a computer device is provided, which may be a server, and its internal structure diagram may be as follows: Figure 20As shown, the computer device includes a processor, memory, input / output (I / O) interfaces, and a communication interface. The processor, memory, and I / O interfaces are connected via a system bus, and the communication interface is also connected to the system bus via the I / O interfaces. The processor provides computational and control capabilities. The memory includes non-volatile storage media and internal memory. The non-volatile storage media stores the operating system, computer programs, and a database. The internal memory provides the environment for the operation of the operating system and computer programs stored in the non-volatile storage media. The database stores battery water content measurement data. The I / O interfaces are used for exchanging information between the processor and external devices. The communication interface is used for communicating with external terminals via a network. When the computer program is executed by the processor, it implements a battery water content measurement method.

[0281] Those skilled in the art will understand that Figure 20 The structure shown is merely a block diagram of a portion of the structure related to the present application and does not constitute a limitation on the computer device to which the present application is applied. Specific computer devices may include more or fewer components than those shown in the figure, or combine certain components, or have different component arrangements.

[0282] In one embodiment, a computer device is provided, including a memory and a processor, wherein the memory stores a computer program, and the processor executes the computer program to implement the technical solution of the battery water content determination method provided in any of the above embodiments.

[0283] The computer device provided in the above embodiments has a similar implementation principle and technical effect to the above method embodiments, and will not be described again here.

[0284] In one embodiment, a computer-readable storage medium is provided, on which a computer program is stored, which, when executed by a processor, implements the technical solution of the battery water content determination method provided in any of the above embodiments.

[0285] The computer-readable storage medium provided in the above embodiments has a similar implementation principle and technical effect to the above method embodiments, and will not be described again here.

[0286] In one embodiment, a computer program product is provided, including a computer program that, when executed by a processor, implements the technical solution of the battery water content determination method provided in any of the above embodiments.

[0287] The computer program product provided in the above embodiments has a similar implementation principle and technical effect to the above method embodiments, and will not be described again here.

[0288] It should be noted that the data involved in this application (including but not limited to data used for analysis, data stored, data displayed, etc.) are all information and data authorized by the user or fully authorized by all parties, and the collection, use and processing of the relevant data must comply with the relevant laws, regulations and standards of the relevant countries and regions.

[0289] Those skilled in the art will understand that all or part of the processes in the methods of the above embodiments can be implemented by a computer program instructing related hardware. The computer program can be stored in a non-volatile computer-readable storage medium, and when executed, it can include the processes of the embodiments of the above methods. Any references to memory, databases, or other media used in the embodiments provided in this application can include at least one of non-volatile and volatile memory. Non-volatile memory can include read-only memory (ROM), magnetic tape, floppy disk, flash memory, optical memory, high-density embedded non-volatile memory, resistive random access memory (ReRAM), magnetic random access memory (MRAM), ferroelectric random access memory (FRAM), phase change memory (PCM), graphene memory, etc. Volatile memory can include random access memory (RAM) or external cache memory, etc. By way of illustration and not limitation, RAM can take many forms, such as Static Random Access Memory (SRAM) or Dynamic Random Access Memory (DRAM). The databases involved in the embodiments provided in this application may include at least one type of relational database and non-relational database. Non-relational databases may include, but are not limited to, blockchain-based distributed databases. The processors involved in the embodiments provided in this application may be general-purpose processors, central processing units, graphics processing units, digital signal processors, programmable logic devices, quantum computing-based data processing logic devices, etc., and are not limited to these.

[0290] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0291] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of this patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this application should be determined by the appended claims.

Claims

1. A method of determining water content of a battery, characterized by, The method comprises: performing moisture determination on a target battery electrode sample according to a first critical temperature to obtain water content of the electrode sample; the first critical temperature is a temperature at which a network structure formed by a cathode main material and an aqueous binder in the target battery is destroyed; determining water content of the target battery according to the water content of the electrode sample; the method comprises: in the case that the heating pipe in the heating device is heated to the first critical temperature by the heating unit in the heating device, the first sample tube with the electrode sample is placed in the cavity of the heating pipe, and in the case that the water vapor generated by heating the electrode sample is sent into an electrolytic cell through the gas outlet pipe connected with the gas outlet of the first sample tube, the water content in the first sample tube is determined according to the electric quantity of the electrolysis process of the water vapor in the electrolytic cell; the real water content of the electrode sample is obtained according to the water content in the first sample tube.

2. The method of claim 1, wherein, the method comprises: obtaining the water content of the empty sample tube; the empty sample tube does not contain the electrode sample; the real water content of the electrode sample is determined according to the water content of the empty sample and the water content in the first sample tube.

3. The method according to claim 1 or 2, characterized in that, the first sample tube is a long-neck sample tube, and the distance between the tube opening of the long-neck sample tube and the heating unit is greater than a preset distance.

4. The method of claim 1, wherein, the water content includes free water content and bound water content, and the method comprises: performing the moisture determination on the second sample tube with the electrode sample according to a second critical temperature to obtain the free water content of the electrode sample; the second critical temperature is less than the first critical temperature; after the free water content of the electrode sample is determined, performing the moisture determination on the second sample tube according to the first critical temperature to obtain the bound water content of the electrode sample.

5. The method of claim 4, wherein, the method comprises: in the case that the heating device is heated to the second critical temperature, the second sample tube with the electrode sample is placed in the heating device to obtain the water content in the second sample tube; the free water content of the electrode sample is determined according to the water content in the second sample tube.

6. The method of claim 5, wherein, the method comprises: obtaining the water content of the empty sample tube; the empty sample tube does not contain the electrode sample; the free water content of the electrode sample is determined according to the water content of the empty sample and the water content in the second sample tube.

7. The method according to claim 5 or 6, characterized in that, the method comprises: The second sample tube is taken out of the heating device, and the second sample tube is re-placed into the heating device with the heating device heated to the first critical temperature, so as to obtain the water content of the pole piece sample.

8. The method of claim 1 or 2, wherein, Before the moisture determination is performed, the method further comprises: The drift value in the gas determination environment is controlled to be less than a preset drift threshold through the drift-stable empty sample tube.

9. The method of claim 1 or 2, wherein, Before the moisture determination of the pole piece sample of the target battery is performed according to the first critical temperature, the method further comprises: In a case where the target battery is baked, the pole piece of the target battery is cut to obtain a pole piece sample of the target battery; the pole piece sample is a sheet-shaped pole piece with a preset size.

10. A water content measurement system characterized by, The water content determination system comprises a heating device and an electrolytic cell; a sample tube placed in the heating device is connected to the electrolytic cell through a gas pipeline; The pole piece sample in the sample tube is used to generate water vapor when the temperature of the heating device reaches a first critical temperature; the first critical temperature is a temperature at which a cross-linked structure formed by a cathode main material and a water-based binder in a target battery is destroyed; The gas pipeline is used to transport the water vapor to the electrolytic cell to obtain the water content of the pole piece sample; The heating device comprises a heating pipeline and a heating unit, and a cavity structure is formed in the middle of the heating pipeline; the sample tube is placed in the cavity of the heating pipeline; The gas pipeline comprises an air inlet pipeline and an air outlet pipeline; an air inlet of the sample tube is connected to an air pump through the air inlet pipeline; an air outlet of the sample tube is connected to the electrolytic cell through the air outlet pipeline; The air pump is used to transport dry gas to the sample tube through the air inlet pipeline, so that the water vapor in the sample tube is transmitted to the electrolytic cell through the air outlet pipeline.

11. The system of claim 10, wherein, The sample tube is a long-neck sample tube; the distance between the tube opening of the sample tube and the heating unit is greater than a preset distance; and the sample tube can withstand a high-temperature material greater than the first critical temperature.

12. The system of claim 10, wherein, The air outlet pipeline is wrapped with a heating belt; the heating belt is used to prevent the water vapor in the sample tube from condensing in the air outlet pipeline.

13. The system of claim 10, wherein, The air inlet pipeline and the air inlet, and the air outlet pipeline and the air outlet are connected through a plurality of adapters, and the connection portions of the adapters are sealed by sealing rings.

14. A battery water content measuring device characterized by comprising: The device comprises: An acquisition module is configured to perform moisture determination on a pole piece sample of a target battery according to a first critical temperature, and to acquire the water content of the pole piece sample; the first critical temperature is a temperature at which a cross-linked structure formed by a cathode main material and a water-based binder in the target battery is destroyed; A determination module is configured to determine the water content of the target battery according to the water content of the pole piece sample; The acquisition module is further configured to: In the case that the heating pipe in the heating device is heated to the first critical temperature by the heating unit in the heating device, the first sample pipe in which the pole piece sample is placed is put into the cavity of the heating pipe, dry gas enters the gas inlet of the first sample pipe through the gas inlet pipeline, the water vapor generated by heating the pole piece sample is sent into the electrolytic cell through the gas outlet pipeline connected with the gas outlet of the first sample pipe, and the water content in the first sample pipe is determined according to the electric quantity of the electrolysis process of the water vapor in the electrolytic cell; and the real water content of the pole piece sample is obtained according to the water content in the first sample pipe.

15. A computer device comprising a memory and a processor, the memory storing a computer program, characterized in that, The computer program, when executed by the processor, implements the steps of the method of any one of claims 1 to 9.

16. A computer readable storage medium having stored thereon a computer program, characterized in that, The computer program, when executed by the processor, implements the steps of the method of any one of claims 1 to 9.

17. A computer program product comprising a computer program, characterized in that, The computer program, when executed by the processor, implements the steps of the method of any one of claims 1 to 9. The computer program, when executed by the processor, implements the steps of the method of any one of claims 1 to 9.

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