WO2022237767A1 - Battery slurry stability test method and apparatus - Google Patents

Abstract

Provided are a battery slurry stability test method and apparatus. The method comprises: obtaining, at different time points, the pressure value Fnmor the pressure intensity value Pnm of at least one test point located below the surface of battery slurry in a container (1) for containing the battery slurry, wherein n is the sign of the test point, and m is the sign of the time point; when there is one test point, the test point being located above the bottom of the battery slurry; calculating the density corresponding to the test point according to the pressure value Fnm or the pressure intensity value Pnm, and obtaining the solid contents of the test point at different time points according to the relationship between the density and the solid content; and determining the stability of the battery slurry according to the plurality of solid contents of the same test point obtained at different time points. In the battery slurry stability test method, the solid content can be obtained without drying and weighting the battery slurry multiple times, such that the test time is shortened, the solid content of the battery slurry can be measured at any height in the container (1) at any time according to requirements, and the operation is simple.

Description

Battery slurry stability detection method and device

This application claims the priority of the Chinese patent application with application number 202110503401.9 submitted to the China Patent Office on May 10, 2021, and the entire content of the above application is incorporated in this application by reference.

technical field

The present application relates to the technical field of lithium batteries, for example, to a method and device for detecting the stability of battery slurry.

Background technique

Lithium battery slurry needs to have good stability, which is an important indicator to ensure battery consistency in the battery production process. With the completion of slurry mixing and the stop of stirring, the battery slurry will appear to settle, flocculate, coalesce and other phenomena, resulting in large particles, which will have a great impact on the subsequent coating and other processes. Therefore, it is very important to detect and control the stability of the battery slurry. The current commonly used method is to store the battery slurry in a glass container, then put the glass container in a drying oven to dry, and test the solid content of the battery slurry at different depths in the beaker at regular intervals after drying.

The current test method for the stability of battery slurry has a problem that the solid content test time is too long. When testing the solid content, the battery slurry needs to be dried in an oven. The drying time is often more than one hour, resulting in a huge labor cost.

Therefore, there is an urgent need for a battery slurry stability detection method and device to solve the above technical problems.

Contents of the invention

The purpose of this application is to propose a battery slurry stability testing method and device.

For this purpose, the application adopts the following technical solutions:

A method for detecting the stability of battery slurry is provided, comprising the steps of:

Obtain the pressure value F _nm or the pressure value P _nm of at least one test point below the liquid level of the battery slurry in the battery slurry container at different time points, wherein, n is the test point label, and m is the time point label;

When the test point is one, the test point is located above the liquid bottom of the battery slurry;

Calculate the density corresponding to the test point from the pressure value F _nm or pressure value P _nm , and obtain the solid content of the test point at different time points through the relationship between density and solid content;

The stability of the battery slurry was judged based on multiple solid contents obtained at different time points at the same test point.

The present application also provides a battery slurry stability detection device, which adopts the above-mentioned battery slurry stability detection method, the device includes a container for holding battery slurry, a detection unit and a controller, the detection The unit is arranged on the inner wall of the container, and the controller communicates with the detection unit to receive the value transmitted by the detection unit and calculate and obtain the solid content of each test point at different time points.

Description of drawings

Figure 1 is a schematic structural diagram of a battery slurry stability detection device provided in Example 1 of the present application;

Fig. 2 is a flow chart of the main steps of the battery slurry stability testing method provided in Example 2 of the present application;

Fig. 3 is a detailed step-by-step flow chart of the battery slurry stability testing method provided in Example 2 of the present application;

Fig. 4 is a detailed flow chart of the battery slurry stability testing method provided in Example 3 of the present application;

FIG. 5 is a flow chart of detailed steps of the battery slurry stability testing method provided in Embodiment 4 of the present application.

In the picture:

1. Container; 2. Detection unit; 3. Controller.

Detailed ways

The application will be further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described here are only used to explain the present application, but not to limit the present application. In addition, it should be noted that, for the convenience of description, only some structures related to the present application are shown in the drawings but not all structures.

In the description of this application, unless otherwise clearly specified and limited, the terms "connected", "connected" and "fixed" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integrated ; It can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediary, and it can be the internal communication of two components or the interaction relationship between two components. Those of ordinary skill in the art can understand the specific meanings of the above terms in this application in specific situations.

In this application, unless otherwise expressly specified and limited, a first feature being "on" or "under" a second feature may include direct contact between the first and second features, and may also include the first and second features Not in direct contact but through another characteristic contact between them. Moreover, "above", "above" and "above" the first feature on the second feature include that the first feature is directly above and obliquely above the second feature, or simply means that the first feature is horizontally deeper than the second feature. "Below", "beneath" and "beneath" the first feature include that the first feature is directly below and obliquely below the second feature, or simply means that the horizontal depth of the first feature is smaller than that of the second feature.

In the description of this embodiment, the terms "up", "down", "right", and other orientations or positional relationships are based on the orientations or positional relationships shown in the drawings, and are only for the convenience of description and simplification of operations, rather than indicating Or imply that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation, and therefore should not be construed as limiting the application. In addition, the terms "first" and "second" are only used to distinguish in description, and have no special meaning.

In the related technology, when the solid content is detected, it needs to be dried, heated and then cooled to obtain the constant weight, and the constant weight is brought into the calculation formula to obtain the solid content. In this method, drying takes a long time, and the solid content data test is not uniform. When sampling battery slurry at different depths, the state of the upper battery slurry will be destroyed, and the authenticity of the solid content of the upper battery slurry cannot be guaranteed later. This embodiment provides a battery slurry stability detection device and a battery slurry stability detection method to solve the above problems.

Embodiment one

This embodiment provides a battery slurry stability detection device, as shown in Figure 1, the device includes a container 1 for battery slurry, a detection unit 2 and a controller 3, and the detection unit 2 is arranged on the inside of the container 1 On the wall, the controller 3 communicates with the detection unit 2 to receive the value transmitted by the detection unit 2 and calculate and obtain the solid content of each test point at different time points. In this embodiment, the controller 3 can be a centralized or distributed controller. For example, the controller 3 can be a single single-chip microcomputer, or it can be composed of distributed multi-block single-chip microcomputers. The control program can be run in the single-chip microcomputers, and then The detection unit 2 is controlled to realize its function.

The detection unit 2 is a pressure sensor or a pressure sensor, which can be selected according to actual needs. The detection unit 2 is arranged on the inner side wall of the container 1 at equal intervals, and the detection unit 2 divides the volume of the battery slurry into equal parts, wherein the number of the detection unit 2 can be one or more than two, when the detection unit 2 is one, the detection unit 2 is located below the liquid level of the battery slurry, and the test unit 2 is located above the liquid bottom of the battery slurry. When there are more than two detection units 2, one of them is located at the liquid bottom of the battery slurry, that is, the bottom wall of the container 1 On the other hand, the rest of the test unit 2 divides the volume of the battery slurry into equal parts. In this embodiment, the container 1 is a glass vessel, specifically a beaker. Since the structure of the beaker is cylindrical, the detection unit 2 can divide the volume of the battery slurry according to It needs to be divided into multiple sections to facilitate the subsequent detection of the solid content of different sections, so as to analyze the stability of the battery slurry according to the obtained solid content. It should be noted that when the number of detection units 2 is greater than two, the distance between the detection unit 2 at the top of the detection units 2 and the liquid surface is the same as the distance between the detection unit 2 and the adjacent detection units 2 .

The battery slurry stability detection device provided in this embodiment, by detecting the pressure or pressure applied to the container 1 by the battery slurry at different detection points, the controller 3 can calculate and obtain the solid content according to the obtained pressure or pressure value, so that Judge the stability of the battery slurry. Compared with the related technology, the device saves the step of drying the battery slurry, and can detect the solid content of the battery slurry at any height in the container 1 at any time as required. The operation is simple, and the measurement marks are uniform and accurate. At the same time, it is possible to avoid taking material in the container 1 and damaging the battery slurry from settling.

Embodiment two

As shown in Figure 2, this embodiment provides a battery slurry stability testing method, which is applied to the battery slurry stability testing device provided in Example 1. The method provided in this example mainly includes the following steps:

Obtain the pressure value F _nm or the pressure value P _nm of at least one test point below the liquid level of the battery slurry in the battery slurry container at different time points, wherein, n is the test point label, and m is the time point label;

When the test point is one, the test point is located above the liquid bottom of the battery slurry;

Calculate the density corresponding to the test point from the pressure value F _nm or pressure value P _nm , and obtain the solid content of the test point at different time points through the relationship between density and solid content;

The stability of the battery slurry was judged based on multiple solid contents obtained at different time points at the same test point.

The battery slurry stability detection method provided in this embodiment obtains the density corresponding to the test point by obtaining the pressure value or pressure value of the test point, and then obtains the solid concentration at different time points through the relationship between density and solid content. Content, the stability of the battery slurry is judged by the solid content analysis obtained at different time points at the same test point. Compared with related technologies, the method provided in this embodiment does not need to dry the battery slurry and weigh the battery slurry multiple times to obtain the solid content, which shortens the test time, and at the same time, it can be measured at any height in the container at any time as needed. Detect the solid content of the battery slurry, and the operation is simple.

The method provided by this embodiment is described in detail below in conjunction with FIG. 3, and the method includes the following steps:

S101. Obtain pressure values F _nm or pressure values P _nm at different depths in the container containing the battery slurry;

Specifically, in this embodiment, pressure or pressure can be obtained through a pressure sensor or a pressure sensor or a probe with a pressure sensor or a pressure sensor, wherein the container is a glass vessel, specifically a beaker, and the pressure sensor or pressure sensor is arranged from top to bottom Set to detect the pressure or pressure applied to the beaker by the battery slurry at different depths in the beaker.

S102. Calculate the uniform battery slurry density ρ _{battery slurry n0} corresponding to the battery slurry at the test point from the pressure value _Fn0 or pressure value _Pn0 of the uniform battery slurry obtained at the test point;

The calculation of uniform battery slurry density ρ _{battery slurry n0} specifically includes:

The pressure value F _n0 or pressure value P _n0 of the uniform battery slurry obtained at the test point calculates the battery slurry average density ρ _{battery slurry average n0} corresponding to the battery slurry;

The average density of _{battery slurry ρ The average n0} of battery slurry is calculated and the corrected density ρ _{correction n0} corresponding to the battery slurry at different depths is obtained, where,

ρ _{correction n0} = (ρ _{battery slurry average n0} nV-ρ _{battery slurry average (n-1)0} (n-1)V)/V;

Wherein, n≥2; V is the segmented volume; the corrected density ρ _{modified n0} is the uniform battery slurry density ρ _{battery slurry n0} .

The uniform battery slurry means that after the battery slurry is poured into the container, the battery slurry is evenly distributed in the container. At this time, the battery slurry is a uniform battery slurry, that is, the battery slurry does not have stratification. It can be understood that the uniform battery slurry density ρ _{battery slurry n0} is the battery slurry density ρ _{battery slurry n1} obtained at the first time. The battery slurry density ρ _{battery slurry n1} means that the battery slurry density is detected immediately after the battery slurry is poured into the container. Of course, in other embodiments, the uniform battery slurry density ρ _{battery slurry n0} is the first time to obtain the battery slurry density, that is, the first time is to perform the battery slurry density after the battery slurry is poured into the container and rested for a period of time. detection. In order to save test time, in this embodiment, the uniform battery slurry density ρ _{battery slurry n0} usually refers to the battery slurry density ρ _{battery slurry n1} obtained at the first time. When m is 0, it does not represent time.

S103. Bring the obtained uniform battery slurry density ρ _{battery slurry n0} into the solid formula 1/ρ _{battery slurry} =C/ρ _powder +(1-C)/ρ _solvent to calculate the actual powder density of the battery slurry ρ _powder , wherein, C is the theoretical solid content of the uniform battery slurry, and the solvent density of the battery slurry ρ _solvent is a known value.

Among them, the theoretical solid content C of uniform battery slurry can be calculated from the homogenate ratio file, and the _solvent density ρsolvent of the battery slurry can be obtained by testing in advance, so _ρsolvent is a known value.

S104. Bring the actual powder density ρ _powder , the battery slurry density ρ _{battery slurry nm} obtained at different time points and the battery slurry solvent density ρ _solvent into the formula:

C _nm = ρ _powder (ρ _solvent - ρ _{battery slurry nm} )/(ρ _solvent ρ _{battery slurry nm} - ρ _powder ρ _{battery slurry nm} ), to obtain the solid content of battery slurry corresponding to different test points at different time points .

It should be noted that different time points can be timed in minutes or hours. In this embodiment, detection is performed according to 0h, 2h, 4h, 8h, 16h, 24h and 48h.

That is, before the S104 step, first obtain the uniform battery slurry density ρ _{battery slurry n0} of the battery slurry in a uniform state; then obtain the actual powder density ρ _powder according to the uniform battery slurry density ρ _{battery slurry n0} , and then The battery slurry density ρ _{battery slurry nm} will change due to the sedimentation and stratification of the battery slurry, so it is necessary to calculate the battery slurry density ρ _{battery slurry nm} at the same detection point at different times, and the actual powder density ρ The _powder is a fixed value, which will not change with the sedimentation and stratification of the battery slurry, so it can be obtained according to the actual powder density ρ _powder , the battery slurry density ρ _{battery slurry nm} obtained at different time points, and the battery slurry solvent The density ρ _{solvent is} brought into the solid content formula to obtain the solid content of different test points at different times. Among them, n represents the detection point, and m represents the time.

S105. Calculate the actual variance of multiple solid contents obtained at different time points at the same test point, and compare the actual variance with the preset variance to determine the stability of the battery slurry.

In this embodiment, when the actual variance is less than the preset variance, it is considered that the stability of the battery slurry is better, and when the actual variance is greater than or equal to the preset variance, it is considered that the stability of the battery slurry is poor. Through the comparison of variance, the solid content fluctuation of the same test point at different time points can be obtained, so as to obtain the test results intuitively.

In the method provided in this embodiment, since the detection of relevant values is obtained by the detection unit arranged in the container, the solid content of the battery slurry in the lower layer can be obtained without stirring the battery slurry in the upper layer during the test process, At the same time, the solid content is obtained by pressure or pressure, which can save detection time, and the detection process does not need to dry the battery slurry.

Embodiment Three

This embodiment provides a battery slurry stability testing method, which is applied to the battery slurry stability testing device provided in Example 1. The method provided in this example mainly includes the following steps:

Obtain the pressure value F _nm or the pressure value P _nm of at least one test point below the liquid level of the battery slurry in the battery slurry container at different time points, wherein, n is the test point label, and m is the time point label;

When the test point is one, the test point is located above the liquid bottom of the battery slurry;

Calculate the density corresponding to the test point from the pressure value F _nm or pressure value P _nm , and obtain the solid content of the test point at different time points through the relationship between density and solid content;

The stability of the battery slurry was judged based on multiple solid contents obtained at different time points at the same test point.

The battery slurry stability detection method provided in this embodiment obtains the density corresponding to the test point by obtaining the pressure value or pressure value of the test point, and then obtains the solid concentration at different time points through the relationship between density and solid content. Content, the stability of the battery slurry is judged by the solid content analysis obtained at different time points at the same test point. Compared with related technologies, the method provided in this embodiment does not need to dry the battery slurry and weigh the battery slurry multiple times to obtain the solid content, which shortens the test time, and at the same time, it can be measured at any height in the container at any time as needed. Detect the solid content of the battery slurry, and the operation is simple.

The method provided by this embodiment is described in detail below in conjunction with FIG. 4, and the method includes the following steps:

S201. Obtain pressure values F _nm or pressure values P _nm at different depths in the container containing the battery slurry;

Specifically, in this embodiment, pressure or pressure can be obtained through a pressure sensor or a pressure sensor or a probe with a pressure sensor or a pressure sensor, wherein the container is a glass vessel, specifically a beaker, and the pressure sensor or pressure sensor is arranged from top to bottom Set to detect the pressure or pressure applied to the beaker by the battery slurry at different depths in the beaker.

In this embodiment, there are multiple test points, and each test point is provided with a detection unit. The multiple detection units are arranged on the inner side wall of the container at equal intervals from top to bottom, and one of the test points is located on the bottom wall of the container. , each test point is provided with a detection unit to obtain a pressure value F _nm or a pressure value P _nm .

S202. Calculate the uniform battery slurry density ρ _{battery slurry n0} corresponding to the battery slurry at the test point from the pressure value _Fn0 or pressure value _Pn0 of the uniform battery slurry obtained at the test point;

The calculation of uniform battery slurry density ρ _{battery slurry n0} specifically includes:

The pressure value F _n0 or pressure value P _n0 of the uniform battery slurry obtained at the test point calculates the battery slurry average density ρ _{battery slurry average n0} corresponding to the battery slurry;

The average density of _{battery slurry ρ The average n0} of battery slurry is calculated and the corrected density ρ _{correction n0} corresponding to the battery slurry at different depths is obtained, where,

ρ _{correction n0} = (ρ _{battery slurry average n0} nV-ρ _{battery slurry average (n-1)0} (n-1)V)/V;

Wherein, n≥2; V is the segmented volume; the corrected density ρ _{modified n0} is the uniform battery slurry density ρ _{battery slurry n0} .

The uniform battery slurry means that after the battery slurry is poured into the container, the battery slurry is evenly distributed in the container. At this time, the battery slurry is a uniform battery slurry, that is, the battery slurry does not have stratification. It can be understood that the uniform battery slurry density ρ _{battery slurry n0} is the battery slurry density ρ _{battery slurry n1} obtained at the first time. The battery slurry density ρ _{battery slurry n1} means that the battery slurry density is detected immediately after the battery slurry is poured into the container. Of course, in other embodiments, the uniform battery slurry density ρ _{battery slurry n0} is the first time to obtain the battery slurry density, that is, the first time is to perform the battery slurry density after the battery slurry is poured into the container and rested for a period of time. detection. In order to save test time, in this embodiment, the uniform battery slurry density ρ _{battery slurry n0} usually refers to the battery slurry density ρ _{battery slurry n1} obtained at the first time. When m is 0, it does not represent time.

S203. Bring the obtained uniform battery slurry density ρ _{battery slurry n0} into the solid formula 1/ρ _{battery slurry} =C/ρ _powder +(1-C)/ρ _solvent to calculate the actual powder density of the battery slurry ρ _powder , wherein, C is the theoretical solid content of uniform battery slurry, and ρ _solvent is a known value.

Among them, the theoretical solid content C of uniform battery slurry can be calculated from the homogenate ratio file, and the _solvent density ρsolvent of the battery slurry can be obtained by testing in advance, so _ρsolvent is a known value.

S204. Obtain the battery slurry density ρ _{battery slurry nm} at different time points, specifically including the following steps:

Calculate the battery slurry average density ρ _{battery slurry average nm corresponding} to the battery slurry by the pressure value _Fnm or pressure value Pnm of the battery slurry obtained at the test point;

Calculate the average density of _{battery slurry ρ average nm} of battery slurry and obtain the corrected density ρ _{corrected nm} of battery slurry at different test points, where,

ρ _{correction nm} = (ρ _{battery slurry average nm} nV-ρ _{battery slurry average (n-1)m} (n-1)V)/V;

Wherein, n≥2; V is the segment volume, ρ _{correction n1} =ρ _{battery slurry n1} ; ρ _{correction 11} =ρ _{battery slurry 11} . The ρ _{correction nm} is the battery slurry density ρ _{battery slurry nm} .

The following content is described using the pressure sensor as an example. As the battery slurry increases with time, there will be a layering phenomenon, so there will be differences in the pressure detection results of the same test point at different time points, and through the relationship between pressure and density and the relationship between density and solid content The relationship between the solid content of the same test point at different time points can be obtained. Different time points can be timed in minutes or hours. In this embodiment, detection is performed according to 0h, 2h, 4h, 8h, 16h, 24h and 48h.

The formula for calculating the average density of the battery slurry is ρ _{battery slurry average nm} = P _nm /gh _n or ρ _{battery slurry average nm} = F _nm /S _n gh _n , where S _n is the cross-sectional area of the container at different test points; h _n is the distance from the detection unit of different test points to the liquid surface. Among them, n represents the detection point, and m represents the time.

The installation depths h ₁ , h ₂ , h ₃ , h ₄ , h ₅ and h ₆ of the pressure sensors in this embodiment are all known values. The installation depth refers to the distance from the pressure sensor to the liquid surface. As n increases, the distance gradually increases, that is, h ₁ <h ₂ <h ₃ <h ₄ <h ₅ <h ₆ ; g is the acceleration of gravity of the earth.

According to the formula P=ρgh, the battery slurry density corresponding to different depths ρ=P/gh can be obtained, where the density ρ is the average density from a single test point to the battery slurry liquid level.

The average density of battery slurry in the area from the first pressure sensor to the liquid level is ρ _{average 1m of battery slurry} = P _1m /gh ₁ ;

The average density of battery slurry in the area from the second pressure sensor to the liquid level ρ average _{battery slurry 2m} = P _2m /gh ₂ ;

The average density of the battery slurry in the area from the third pressure sensor to the liquid level ρ Average _{battery slurry 3m} = P _3m /gh ₃ ;

The average density of the battery slurry in the area from the fourth pressure sensor to the liquid level ρ average _{battery slurry 4m} = P _4m /gh ₄ ;

The average density of battery slurry in the area from the fifth pressure sensor to the liquid level ρ average _{battery slurry 5m} = P _5m /gh ₅ ;

The average density of the battery slurry in the region from the sixth pressure sensor to the liquid level ρ _{average 6m of the battery slurry} =P _6m /gh ₆ .

Because the density of the battery slurry is different at each depth, the density represented by the _{average 1m} of the ρ _{battery slurry to the average 6m} of the ρ battery slurry here is the average density of the battery slurry from the test point to the liquid surface. The corrected density ρ _{corrected nm} can be obtained from the average battery slurry density ρ _{battery slurry average nm} at each depth. The battery slurry in the container is divided into six parts with each pressure sensor as the boundary. The depth of each part is already very small, and it can be approximately considered that the internal substances of each part are uniform.

Calculating and obtaining the corrected density ρ _{corrected nm} corresponding to the battery slurry at different depths from the battery slurry average density ρ _{battery slurry average} nm includes the following steps:

Let the volume of each equal segment be V, where the formula for calculating the corrected density ρ _{corrected nm} is:

ρ _{correction nm} = (ρ _{battery slurry average nm} nV-ρ _{battery slurry average (n-1)m} (n-1)V)/V;

Where n≥2, V is the volume of the segment, ρ _{correction n1} = ρ _{battery slurry n1} ; ρ _{correction 11} = ρ _{battery slurry 11} , ρ _{correction nm} is the battery slurry density ρ _{battery slurry nm} .

S205. Bring the actual powder density ρ _powder , the battery slurry density ρ _{battery slurry nm} obtained at different time points and the battery slurry solvent density ρ _solvent into the formula:

C _nm = ρ _powder (ρ _solvent - ρ _{battery slurry nm} )/(ρ _solvent ρ _{battery slurry nm} - ρ _powder ρ _{battery slurry nm} ), to obtain the solid content of battery slurry corresponding to different test points at different time points .

That is, before the step S205, first obtain the uniform battery slurry density ρ _{battery slurry n0} of the battery slurry in a uniform state; then obtain the actual powder density ρ _powder according to the uniform battery slurry density ρ _{battery slurry n0} , the actual powder The material density ρ _powder is a fixed value, which will not change with the sedimentation and stratification of the battery slurry, so it can be obtained according to the actual powder density ρ _powder , the battery slurry density ρ _{battery slurry nm} and the battery slurry obtained at different time points. The slurry solvent density ρ _{solvent is} brought into the solid content formula to obtain the solid content of different test points at different times.

S206. Calculate the actual variance of multiple solid contents obtained at different time points at the same test point, and compare the actual variance with the preset variance to determine the stability of the battery slurry.

S207. If the actual variance is smaller than the preset variance, the battery slurry has better stability.

S208. If the actual variance is greater than or equal to the preset variance, the stability of the battery slurry is poor.

In this embodiment, when the actual variance is less than the preset variance, it is considered that the stability of the battery slurry is better, and when the actual variance is greater than or equal to the preset variance, it is considered that the stability of the battery slurry is poor. Through the comparison of variance, the solid content fluctuation of the same test point at different time points can be obtained, so as to obtain the test results intuitively.

For example, in this embodiment, the value range of the preset variance is 0-3%, more preferably, the value range of the preset variance is 0-2%, of course, the optional value of the preset variance is 0.5%, 1%, 1.5% or 2% pip value. The smaller the actual variance value, the better the stability.

In the method provided in this embodiment, since the detection of relevant values is obtained by the detection unit arranged in the container, the solid content of the battery slurry in the lower layer can be obtained without stirring the battery slurry in the upper layer during the test process, At the same time, the solid content is obtained by pressure or pressure, which can save detection time, and the detection process does not need to dry the battery slurry. In this embodiment, each region in the container is decomposed to obtain corrected densities corresponding to different test points, thereby compensating for test differences caused by inconsistencies in the density of the battery slurry, making the measurement standard uniform and accurate.

Embodiment Four

This embodiment provides a battery slurry stability testing method, which is applied to the battery slurry stability testing device provided in Example 1. The method provided in this example mainly includes the following steps:

Obtain the pressure value F _nm or the pressure value P _nm of at least one test point below the liquid level of the battery slurry in the battery slurry container at different time points, wherein, n is the test point label, and m is the time point label;

When the test point is one, the test point is located above the liquid bottom of the battery slurry;

Calculate the density corresponding to the test point from the pressure value F _nm or pressure value P _nm , and obtain the solid content of the test point at different time points through the relationship between density and solid content;

The stability of the battery slurry was judged based on multiple solid contents obtained at different time points at the same test point.

The battery slurry stability detection method provided in this embodiment obtains the density corresponding to the test point by obtaining the pressure value or pressure value of the test point, and then obtains the solid concentration at different time points through the relationship between density and solid content. Content, the stability of the battery slurry is judged by the solid content analysis obtained at different time points at the same test point. Compared with related technologies, the method provided in this embodiment does not need to dry the battery slurry and weigh the battery slurry multiple times to obtain the solid content, which shortens the test time, and at the same time, it can be measured at any height in the container at any time as needed. Detect the solid content of the battery slurry, and the operation is simple.

The method provided by this embodiment is described in detail below in conjunction with FIG. 5, and the method includes the following steps:

S301. Obtain pressure values F _nm or pressure values P _nm at different depths in the container holding the battery slurry;

Specifically, in this embodiment, pressure or pressure can be obtained through a pressure sensor or a pressure sensor or a probe with a pressure sensor or a pressure sensor, wherein the container is a glass vessel, specifically a beaker, and the pressure sensor or pressure sensor is arranged from top to bottom Set to detect the pressure or pressure applied to the beaker by the battery slurry at different depths in the beaker.

In this embodiment, there are multiple test points, and each test point is provided with a detection unit. The multiple detection units are arranged on the inner side wall of the container at equal intervals from top to bottom, and one of the test points is located on the bottom wall of the container. , each test point is provided with a detection unit to obtain a pressure value F _nm or a pressure value P _nm .

S302. Calculate the uniform battery slurry density ρ _{battery slurry n0} corresponding to the battery slurry at the test point from the pressure value _Fn0 or pressure value _Pn0 of the uniform battery slurry obtained at the test point;

The calculation of uniform battery slurry density ρ _{battery slurry n0} specifically includes:

The pressure value F _n0 or pressure value P _n0 of the uniform battery slurry obtained at the test point calculates the battery slurry average density ρ _{battery slurry average n0} corresponding to the battery slurry;

The average density of _{battery slurry ρ The average n0} of battery slurry is calculated and the corrected density ρ _{correction n0} corresponding to the battery slurry at different depths is obtained, where,

ρ _{correction n0} = (ρ _{battery slurry average n0} nV-ρ _{battery slurry average (n-1)0} (n-1)V)/V;

Wherein, n≥2; V is the segmented volume; the corrected density ρ _{modified n0} is the uniform battery slurry density ρ _{battery slurry n0} .

The uniform battery slurry means that after the battery slurry is poured into the container, the battery slurry is evenly distributed in the container. At this time, the battery slurry is a uniform battery slurry, that is, the battery slurry does not have stratification. It can be understood that the uniform battery slurry density ρ _{battery slurry n0} is the battery slurry density ρ _{battery slurry n1} obtained at the first time. The battery slurry density ρ _{battery slurry n1} means that the battery slurry density is detected immediately after the battery slurry is poured into the container. Of course, in other embodiments, the uniform battery slurry density ρ _{battery slurry n0} is the first time to obtain the battery slurry density, that is, the first time is to perform the battery slurry density after the battery slurry is poured into the container and rested for a period of time. detection. In order to save test time, in this embodiment, the uniform battery slurry density ρ _{battery slurry n0} usually refers to the battery slurry density ρ _{battery slurry n1} obtained at the first time. When m is 0, it does not represent time.

S303. Bring the obtained uniform battery slurry density ρ _{battery slurry n0} into the solid formula 1/ρ _{battery slurry} =C/ρ _powder +(1-C)/ρ _solvent to calculate the actual powder density of the battery slurry ρ _powder , wherein, C is the theoretical solid content of uniform battery slurry, and ρ _solvent is a known value.

Among them, the theoretical solid content C of uniform battery slurry can be calculated from the homogenate ratio file, and the _solvent density ρsolvent of the battery slurry can be obtained by testing in advance, so _ρsolvent is a known value.

S304. Obtain the battery slurry density ρ _{battery slurry nm} at different time points, specifically including the following steps:

Calculate the battery slurry average density ρ _{battery slurry average nm corresponding} to the battery slurry by the pressure value _Fnm or pressure value Pnm of the battery slurry obtained at the test point;

Calculate the average density of _{battery slurry ρ average nm} of battery slurry and obtain the corrected density ρ _{corrected nm} of battery slurry at different test points, where,

ρ _{correction nm} = (ρ _{battery slurry average nm} nV-ρ _{battery slurry average (n-1)m} (n-1)V)/V;

Among them, n≥2; V is the segment volume, ρ _{correction n1} = ρ _{battery slurry n1} ; ρ _{correction 11} = ρ _{battery slurry 11} , ρ _{correction nm} is the battery slurry density ρ _{battery slurry nm} .

The following content is described using the pressure sensor as an example. As the battery slurry increases with time, there will be a layering phenomenon, so there will be differences in the pressure detection results of the same test point at different time points, and through the relationship between pressure and density and the relationship between density and solid content The relationship between the solid content of the same test point at different time points can be obtained. Different time points can be timed in minutes or hours. In this embodiment, detection is performed according to 0h, 2h, 4h, 8h, 16h, 24h and 48h.

The formula for calculating the average density of the battery slurry is ρ _{battery slurry average nm} = P _nm /gh _n or ρ _{battery slurry average nm} = F _nm /S _n gh _n , where S _n is the cross-sectional area of the container at different test points; h _n is the distance from the detection unit of different test points to the liquid surface.

The installation depths h ₁ , h ₂ , h ₃ , h ₄ , h ₅ and h ₆ of the pressure sensors in this embodiment are all known values. The installation depth refers to the distance from the pressure sensor to the liquid surface. As n increases, the distance gradually increases, that is, h ₁ <h ₂ <h ₃ <h ₄ <h ₅ <h ₆ ; g is the acceleration of gravity of the earth.

According to the formula P=ρgh, the battery slurry density corresponding to different depths ρ=P/gh can be obtained, where the density ρ is the average density from a single test point to the battery slurry liquid level.

The average density of battery slurry in the area from the first pressure sensor to the liquid level is ρ _{average 1m of battery slurry} = P _1m /gh ₁ ;

The average density of battery slurry in the area from the second pressure sensor to the liquid level ρ average _{battery slurry 2m} = P _2m /gh ₂ ;

The average density of the battery slurry in the area from the third pressure sensor to the liquid level ρ Average _{battery slurry 3m} = P _3m /gh ₃ ;

The average density of the battery slurry in the area from the fourth pressure sensor to the liquid level ρ average _{battery slurry 4m} = P _4m /gh ₄ ;

The average density of battery slurry in the area from the fifth pressure sensor to the liquid level ρ average _{battery slurry 5m} = P _5m /gh ₅ ;

The average density of the battery slurry in the region from the sixth pressure sensor to the liquid level ρ _{average 6m of the battery slurry} =P _6m /gh ₆ .

Because the density of the battery slurry is different at each depth, the density represented by the _{average 1m} of the ρ _{battery slurry to the average 6m} of the ρ battery slurry here is the average density of the battery slurry from the test point to the liquid surface. The corrected density ρ _{corrected nm} can be calculated from the battery slurry average density ρ _{battery slurry average nm} at each depth. The battery slurry in the container is divided into six parts with each pressure sensor as the boundary. The depth of each part is already very small, and it can be approximately considered that the internal substances of each part are uniform.

Calculate and obtain the corrected density ρ _{corrected nm} corresponding to the battery slurry at different depths from the average density of the _{battery slurry ρ average nm} of the battery slurry.

Let the volume of each equal segment be V, where the formula for calculating the corrected density ρ _{corrected nm} is:

ρ _{correction nm} = (ρ _{battery slurry average nm} nV-ρ _{battery slurry average (n-1)m} (n-1)V)/V;

Where n≥2, V is the segmented volume, ρ _{correction n1} =ρ _{battery slurry n1} ; ρ _{correction 11} =ρ _{battery slurry 11} .

The corrected density ρ _{corrected nm} is the battery slurry density ρ _{battery slurry nm} .

S305. Bring the actual powder density ρ _powder , the battery slurry density ρ _{battery slurry nm} obtained at different time points and the battery slurry solvent density ρ _solvent into the formula:

C _nm = ρ _powder (ρ _solvent - ρ _{battery slurry nm} )/(ρ _solvent ρ _{battery slurry nm} - ρ _powder ρ _{battery slurry nm} ), to obtain the solid content of battery slurry corresponding to different test points at different time points .

That is, before the step S305, first obtain the uniform battery slurry density ρ _{battery slurry n0} of the battery slurry in a uniform state; then obtain the actual powder density ρ _powder according to the uniform battery slurry density ρ _{battery slurry n0} , the actual powder The material density ρ _powder is a fixed value, which will not change with the sedimentation and stratification of the battery slurry, so it can be obtained according to the actual powder density ρ _powder , the battery slurry density ρ _{battery slurry nm} and the battery slurry obtained at different time points. The slurry solvent density ρ _{solvent is} brought into the solid content formula to obtain the solid content of different test points at different times.

S306. Fit multiple solid contents obtained at different time points at the same test point into a curve or a line segment, and judge whether the curvature change of the curve is smaller than a preset curvature change, or judge whether the slope of the straight line is smaller than a preset slope.

S307. If the curvature change of the fitted curve is smaller than the preset curvature change, or the slope of the fitted line segment is smaller than the preset slope, the stability is better;

S308. If the curvature change of the curve obtained by fitting is greater than or equal to the preset curvature change, or the slope of the line segment obtained by fitting is greater than or equal to the preset slope, the stability is poor.

The smaller the absolute value of the slope of the solid content change curve at the same test point, the better the slurry stability. Under normal circumstances, the absolute value of the slope of the upper layer slurry gradually decreases, and the speed of the decrease of the upper solid content becomes slower and slower, and the speed of the increase of the upper layer solid content becomes slower and slower.

In the method provided in this embodiment, since the detection of relevant values is obtained by the detection unit arranged in the container, the solid content of the battery slurry in the lower layer can be obtained without stirring the battery slurry in the upper layer during the test process, At the same time, the solid content is obtained by pressure or pressure, which can save detection time, and the detection process does not need to dry the battery slurry. In this embodiment, each region in the container is decomposed to obtain corrected densities corresponding to different test points, thereby compensating for test differences caused by inconsistencies in the density of the battery slurry, making the measurement standard uniform and accurate.

The purpose of this application is to propose a battery slurry stability detection method and device, which can measure and store the solid content at any depth in the beaker at any time, and judge the stability of the battery slurry according to the solid content, and the operation is simple.

In addition, the above are only some embodiments and applied technical principles of the present application. Those skilled in the art will understand that the present application is not limited to the specific embodiments described herein, and various obvious changes, readjustments and substitutions can be made by those skilled in the art without departing from the protection scope of the present application. Therefore, although the present application has been described in detail through the above embodiments, the present application is not limited to the above embodiments, and can also include more other equivalent embodiments without departing from the concept of the present application, and the present application The scope is determined by the scope of the appended claims.

Claims (10)

1. A method for detecting the stability of battery slurry, comprising the steps of:

   Obtain the pressure value F _nm or the pressure value P _nm of at least one test point below the liquid level of the battery slurry in the battery slurry container at different time points, wherein, n is the test point label, and m is the time point label;

   When the test point is one, the test point is located above the liquid bottom of the battery slurry;

   Calculate the density corresponding to the test point from the pressure value F _nm or pressure value P _nm , and obtain the solid content of the test point at different time points through the relationship between density and solid content;

   The stability of the battery slurry was judged based on multiple solid contents obtained at different time points at the same test point.
2. The battery slurry stability detection method according to claim 1, wherein said calculating the density corresponding to the test point from the pressure value _Fnm or the pressure value _Pnm comprises the following steps:

   Calculate the uniform battery slurry density ρ _{battery slurry n0} corresponding to the battery slurry at the test point from the pressure value _Fn0 or pressure value _Pn0 of the uniform battery slurry obtained at the test point;

   Bring the obtained uniform battery slurry density ρ _{battery slurry n0} into the solid formula 1/ρ _{battery slurry n} = C/ρ _powder + (1-C)/ρ _solvent to calculate the actual powder density ρ of the battery slurry _Powder , wherein, C is the theoretical solid content of the uniform battery slurry, and the solvent density ρ of the battery slurry _solvent is a known value.
3. The method for detecting the stability of battery slurry according to claim 2, wherein said obtaining the solid content of the test point at different time points through the relationship between the density and the solid content includes:

   The actual powder density ρ _powder , the battery slurry density ρ _{battery slurry nm} obtained at different time points and the battery slurry solvent density ρ _solvent are brought into the formula:

   C _nm = ρ _powder (ρ _solvent - ρ _{battery slurry nm} )/(ρ _solvent ρ _{battery slurry nm} - ρ _powder ρ _{battery slurry nm} ), to obtain the solid content of battery slurry corresponding to different test points at different time points .
4. The battery slurry stability detection method according to claim 3, wherein there are multiple test points, each of which is provided with a detection unit, and the plurality of detection units are equally spaced from top to bottom It is arranged on the inner side wall of the container, wherein one of the test points is located on the bottom wall of the container, and each of the test points is provided with the detection unit to obtain the pressure value _Fnm or the pressure Value _Pnm .
5. The battery slurry stability detection method according to claim 4, wherein, after the battery slurry is poured into the container, the battery slurry is uniformly distributed in the container, and the uniform _battery slurry density ρ The battery _{slurry n0} is the battery slurry density ρ _{battery slurry n1} obtained at the first time.
6. The battery slurry stability detection method according to claim 4, wherein obtaining a uniform battery slurry density ρ _{battery slurry n0} comprises:

   Calculate the battery slurry average density ρ _{battery slurry average n0} corresponding to the battery slurry from the pressure value F _n0 or pressure value P _n0 of the uniform battery slurry obtained at the test point;

   The average density of _{battery slurry ρ The average n0} of battery slurry is calculated and the corrected density ρ _{correction n0} corresponding to the battery slurry at different depths is obtained, where,

   ρ _{correction n0} = (ρ _{battery paddle average n0} nV-ρ _{battery paddle average (n-1)0} (n-1)V)/V;

   Wherein, n≥2; V is the segmented volume; the corrected density ρ _{modified n0} is the uniform battery slurry density ρ _{battery slurry n0} .
7. The battery slurry stability detection method according to claim 6, wherein obtaining the battery slurry density p _{battery slurry nm} at different time points comprises the steps of:

   Calculate the battery slurry average density ρ _{battery slurry average nm corresponding} to the battery slurry by the pressure value _Fnm or pressure value Pnm of the battery slurry obtained at the test point;

   Calculate the average density of _{battery slurry ρ average nm} of battery slurry and obtain the corrected density ρ _{corrected nm} of battery slurry at different test points, where,

   ρ _{correction nm} = (ρ _{battery slurry average nm} nV-ρ _{battery slurry average (n-1)m} (n-1)V)/V;

   Among them, n ≥ 2; V is the segmented volume, ρ _{correction n1} = ρ _{battery slurry n1} ; ρ _{correction 11} = ρ _{battery slurry 11} ; ρ _{correction nm} is the battery slurry density ρ _{battery slurry nm} ;

   The formula for calculating the average density of the battery slurry is ρ _{battery slurry average nm} = P _nm /gh _n or ρ _{battery slurry average nm} = F _nm /S _n gh _n , where S _n is the cross-sectional area of the container at different test points ; The h _n is the distance from the detection unit to the liquid surface at different test points.
8. The battery slurry stability detection method according to claim 1, wherein said judging the stability of the battery slurry according to multiple solid contents obtained at different time points at the same test point comprises:

   Calculate the actual variance of multiple solid contents obtained at different time points at the same test point, and compare the actual variance with the preset variance to judge the stability of the battery slurry.
9. The battery slurry stability detection method according to claim 1, wherein said judging the stability of the battery slurry according to multiple solid contents obtained at different time points at the same test point comprises:

   Multiple solid contents obtained at different time points at the same test point are fitted into a curve or a line segment, and the stability of the battery slurry is judged according to the curvature change of the curve or the slope of the line segment.
10. A battery slurry stability detection device, which adopts the battery slurry stability detection method according to any one of claims 1-9, said device comprising a battery slurry container (1), a detection unit (2 ) and a controller (3), the detection unit (2) is arranged on the inner wall of the container (1), and the controller (3) communicates with the detection unit (2) to receive the The value transmitted by the detection unit (2) is calculated to obtain the solid content of each test point at different time points.

Images