CN118050363A

CN118050363A - Detection method and detection device

Info

Publication number: CN118050363A
Application number: CN202410451985.3A
Authority: CN
Inventors: 邓雅岑; 罗东升; 马智文
Original assignee: Contemporary Amperex Technology Co Ltd
Current assignee: Contemporary Amperex Technology Co Ltd
Priority date: 2024-04-16
Filing date: 2024-04-16
Publication date: 2024-05-17
Anticipated expiration: 2044-04-16
Also published as: CN118050363B

Abstract

The present application relates to a detection method and a detection apparatus. The detection method is used for detecting the fibers in the graphite powder; the detection method comprises the following steps: mixing graphite powder with preset mass and a separating agent aqueous solution with preset volume to form slurry, so that the fiber and graphite particles in the graphite powder are layered, the fiber is positioned on the top layer of the slurry, and the graphite particles are positioned on the bottom layer of the slurry; wherein the density of the aqueous separating agent solution is less than the density of the graphite particles and greater than the density of the fibers; separating the top layer of the slurry; the number of fibers in the top layer of the slurry is obtained. The separating agent aqueous solution can be used for well separating graphite powder and fibers, and the detection method does not need to consume a large amount of pure water, so that the consumption of the pure water can be reduced, and the detection cost of the detection method is reduced.

Description

Detection method and detection device

Technical Field

The application relates to the technical field of batteries, in particular to a detection method and a detection device.

Background

The negative electrode material of the battery comprises graphite powder, and the quality of the graphite powder is a critical influencing factor for quality control of the battery. Therefore, the impurities in the graphite powder are required to be detected so as to be used as the basis for quality control of the graphite powder.

However, the detection method of graphite particles of the related art requires a large amount of pure water to be consumed.

Disclosure of Invention

Based on this, it is necessary to provide a detection method and a detection apparatus for the problem that a large amount of pure water is consumed in the detection method of graphite particles of the related art.

According to a first aspect of the present application, there is provided a detection method for detecting fibres in graphite powder; the detection method comprises the following steps: mixing graphite powder with preset mass and a separating agent aqueous solution with preset volume to form slurry, so that the fiber and graphite particles in the graphite powder are layered, the fiber is positioned on the top layer of the slurry, and the graphite particles are positioned on the bottom layer of the slurry; wherein the density of the aqueous separating agent solution is less than the density of the graphite particles and greater than the density of the fibers; separating the top layer of the slurry; the number of fibers in the top layer of the slurry is obtained.

In the technical scheme of the application, because the density of the separating agent aqueous solution is smaller than that of the graphite particles and is larger than that of the fibers, after the preset mass of graphite powder and the preset volume of separating agent aqueous solution are mixed to form slurry, the graphite powder can be deposited on the bottom layer of the slurry under the action of gravity due to the fact that the density of the separating agent aqueous solution is larger than that of the separating agent aqueous solution, and the fibers float on the top layer of the slurry due to the fact that the density of the separating agent aqueous solution is smaller than that of the separating agent aqueous solution, which is equivalent to layering the fibers and the graphite particles, then the top layer of the slurry is separated, and the number of the fibers in the top layer of the slurry is obtained.

In one embodiment, the aqueous separating agent solution is a colorless transparent solution. Because the separating agent aqueous solution is colorless transparent solution, whether fibers and graphite particles in the slurry are layered or not is conveniently observed, so that the top layer of the slurry is separated according to the requirement, and the operation convenience of the detection method can be improved.

In one embodiment, the aqueous separating agent comprises an aqueous zinc chloride solution. On the one hand, the zinc chloride aqueous solution is colorless and transparent aqueous solution, so that the top layer of the slurry is conveniently separated according to the requirement, and the operation convenience of the detection method can be improved. On the other hand, by dissolving zinc chloride of a certain mass in a certain volume of pure water, an aqueous zinc chloride solution satisfying the density condition that the density of the aqueous zinc chloride solution is smaller than that of graphite particles and greater than that of fibers can be easily prepared, and the convenience of detection can be improved. In addition, the zinc chloride aqueous solution is nontoxic and non-corrosive, so that the safety of the detection method can be improved, and the pollution degree of the subsequent water treatment of the detection method can be reduced.

In one embodiment, the aqueous zinc chloride solution has a density of 1.5g/cm ³-1.8g/cm³. The density of the prepared zinc chloride aqueous solution is selected within a proper range, for example, 1.5g/cm ³-1.8g/cm³, so that the density of the prepared zinc chloride aqueous solution is greatly different from that of graphite particles, the zinc chloride aqueous solution is favorable for better depositing the graphite particles on the bottom layer of the slurry under the action of gravity, and further, the zinc chloride aqueous solution can be better utilized to enable fibers and the graphite particles to be arranged in a layered manner, so that the top layer of the slurry is separated later, the number of fibers in the top layer of the slurry is obtained, and further, the reliability of the detection method provided by the application can be improved.

In one embodiment, the preset mass is a and the preset volume is V, wherein the preset mass and the preset volume satisfy the following conditions: v/a is more than or equal to 1.5ml/g. In order to separate the fibers and graphite particles better, it is necessary to mix a predetermined mass of graphite powder with a sufficient volume of an aqueous solution of a separating agent so that the fibers and graphite particles can be separated by a distance within the slurry, thereby facilitating the separation of the fibers located on the top layer of the slurry to obtain the number of fibers, and therefore, the predetermined mass and predetermined volume need to satisfy the following conditions: v/a is more than or equal to 1.5ml/g.

In one embodiment, the preset mass and preset volume satisfy the following conditions: v/a is less than or equal to 1.5ml/g and less than or equal to 3ml/g.

In one embodiment, the separation of the top layer of slurry comprises: the top layer of the slurry is separated by adopting a drainage mode. The amount of fibers in the top layer of the slurry is conveniently obtained.

In one embodiment, the detection method further comprises, prior to separating the top layer of slurry: a flocculant is added to the slurry. The flocculant can interact with graphite particles in the slurry to form larger flocculation, so that the graphite particles can be flocculated and precipitated, and the fiber and the graphite particles can be better and faster layered by the flocculant, so that the top layer of the slurry can be conveniently and better separated out, and the quantity of the fiber in the top layer of the slurry can be conveniently obtained.

In one embodiment, the flocculant comprises a water-soluble flocculant. The water-soluble flocculant is selected, so that the flocculant can be well dissolved in water, the flocculant can be more quickly contacted with graphite particles in the slurry, the graphite particles can be better flocculated and precipitated, further, the fiber and the graphite particles can be better arranged in a layering manner, the follow-up better separation of the top layer of the slurry is facilitated, and the number of the fibers in the top layer of the slurry is obtained.

In one embodiment, the mass of water in the aqueous separating agent solution is b, the mass of flocculant added is greater than or equal to 0.002b, and the mass units of graphite particles and flocculant are grams. In order to better bring the flocculant into more and faster contact with the graphite particles in the slurry, sufficient flocculant may be added based on the mass of water in the aqueous separating agent solution, e.g., the mass of water in the aqueous separating agent solution is b, and the mass of flocculant added is greater than or equal to 0.002b.

In one embodiment, the mass of water in the aqueous separating agent solution is b and the mass of flocculant added is 0.0025b to 0.01b.

In one embodiment, the detection method further comprises, prior to separating the top layer of slurry: and treating the slurry added with the flocculant by adopting a centrifugal separation mode. The adoption of the centrifugal separation mode can enable fibers and graphite particles to be layered more quickly and better, and further the top layer of the slurry can be separated out better, so that the number of fibers in the top layer of the slurry can be obtained.

In one embodiment, the detection method further comprises, prior to separating the top layer of slurry: mixing graphite powder, a separating agent aqueous solution and a flocculating agent in a stirring mode. The method can fully disperse graphite powder, the separating agent aqueous solution and the flocculating agent, is favorable for the interaction of the flocculating agent and the graphite particles to flocculate and precipitate the graphite particles, and further can better utilize the separating agent aqueous solution to realize layering arrangement of the fibers and the graphite particles so as to obtain the number of the fibers in the top layer of the slurry.

In one embodiment, graphite powder, the aqueous solution of the separating agent and the flocculating agent are mixed in a stirring manner, and specifically comprises the following steps: mixing graphite powder, a separating agent aqueous solution and a flocculating agent for a first preset time at a first preset stirring speed; mixing graphite powder, a separating agent aqueous solution and a flocculating agent for a second preset time at a second preset stirring speed; wherein the first preset stirring speed is smaller than the second preset stirring speed. Firstly, mixing graphite powder, a separating agent aqueous solution and a flocculating agent for a first preset time at a small stirring speed, so that the probability of flying phenomenon of the graphite powder is reduced; and mixing the graphite powder, the separating agent aqueous solution and the flocculating agent for a second preset time at a larger stirring speed, so that the flocculating agent is in contact with the graphite particles sufficiently, the flocculating agent and the graphite particles interact to flocculate and precipitate the graphite particles, and the separating agent aqueous solution can be better utilized to enable the fibers and the graphite particles to be arranged in a layered manner, so that the number of the fibers in the top layer of the slurry can be acquired subsequently.

In one embodiment, the detection method further comprises, prior to separating the top layer of slurry: a surfactant is added to the slurry. Because one end of the surfactant is a hydrophilic group and the other end of the surfactant is a hydrophobic group, the hydrophobic group of the surfactant can be utilized to adsorb graphite particles in the graphite powder, and then the hydrophilic group of the surfactant can be utilized to ensure that the graphite particles are dispersed more uniformly in the separating agent aqueous solution, so that fibers doped among the graphite particles can be better separated, the separation effect of the fibers and the graphite particles can be improved, and the number of the fibers can be more accurately detected by using the detection method.

In one embodiment, the preset mass is a and the mass of the added surfactant is c; wherein c is more than or equal to 0.02a and less than or equal to 0.07a, and the mass units of the graphite particles and the surfactant are gram. According to the preset mass, the mass of the added surfactant is set in a proper range, so that the hydrophilic groups of the surfactant can be better utilized to uniformly disperse graphite particles in the aqueous solution of the separating agent, the separation effect of fibers and the graphite particles can be improved, and further, the detection method can be used for detecting the number of the fibers more accurately.

In one embodiment, 0.03 a.ltoreq.c.ltoreq.0.06 a.

In one embodiment, the obtaining the number of fibers in the top layer of the slurry specifically includes: flowing the top layer of the separated slurry through the visual pool at a preset speed; a plurality of inspection images of the fibers flowing through the visual pool are acquired and the number of fibers in the top layer of the slurry is determined based on the plurality of inspection images. The labor cost of manual counting can be reduced, and the detection method can be used for detecting the number of fibers in the graphite powder more accurately and more efficiently.

According to a first aspect of the present application, there is provided a detection device, which is applied to the detection method of any one of the above embodiments, and which includes a mixing vessel having a mixing chamber for mixing graphite powder and an aqueous solution of a separating agent, a separating mechanism provided on the mixing vessel, and an obtaining mechanism for separating a top layer of slurry from the mixing chamber. The acquisition mechanism is arranged on one side of the mixing container and is used for acquiring the quantity of fibers in the top layer of the slurry. The detection device can be applied to the detection method, so that the use amount of pure water can be reduced, and the detection cost is reduced.

In one of the embodiments, the top of the side wall of the mixing vessel is provided with a separation outlet in communication with the mixing chamber; the separating mechanism comprises a drainage piece which is used for guiding the top layer of the slurry to flow out towards the separating outlet. The graphite powder and the separating agent aqueous solution are mixed to obtain the slurry, and after the fibers are positioned on the top layer of the slurry, the graphite particles are positioned on the bottom layer of the slurry, the top layer of the slurry can be guided to flow out towards the separating outlet through the drainage piece, so that the number of the fibers in the top layer of the slurry can be conveniently obtained.

In one embodiment, the separation mechanism further comprises an air supply member connected to the flow guide member, the air supply member having an air supply port, the flow guide member having an air blowing port disposed toward the separation outlet, the air blowing port being in communication with the separation outlet and the air supply port, respectively. The gas which does not react with the substances in the mixing cavity, such as air or inert gas, can be introduced into the mixing cavity through the gas supply port and the gas blowing port of the gas supply piece, and is combined with the gas blowing port to be arranged towards the separation outlet, so that the gas blown into the mixing cavity from the gas blowing port can flow towards the separation outlet, then the top layer of the slurry is driven to flow towards the separation outlet, and the top layer of the slurry can be separated from the mixing cavity, so that the quantity of fibers in the top layer of the slurry can be obtained later.

In one embodiment, the detection device further comprises a visual pool outside the mixing container and on one side of the acquisition mechanism, the visual pool having a visual cavity communicating with the separation outlet, the visual pool being located on the underside of the separation outlet in a direction parallel to the top of the mixing container and directed towards the bottom thereof; the visualization pool includes a visualization portion for viewing the fibers. After the top layer of the slurry is separated from the mixing cavity, the slurry can slowly flow into the visible pool under the action of gravity, and the fibers flowing into the visible pool can be observed through the visible part, so that the acquisition mechanism can be used for acquiring the number of the fibers in the top layer of the slurry.

In one embodiment, the detection device further comprises a flow guide pipe and an ultrasonic disperser, one end of the flow guide pipe is communicated with the separation outlet, the other end of the flow guide pipe is communicated with the visible cavity, and the ultrasonic disperser is arranged on the flow guide pipe. After the top layer of the slurry is separated from the mixing cavity, before the top layer of the slurry flows into the visual pool, the slurry can flow through the flow guide pipe, and fibers in the top layer of the slurry are fully dispersed in the top layer of the slurry through the ultrasonic disperser arranged on the flow guide pipe, so that the condition that the fibers are clustered is reduced, and the number of the fibers in the top layer of the slurry is better acquired.

In one embodiment, the acquisition mechanism includes a high speed camera directed toward the viewable portion. A plurality of inspection images of the fibers flowing into the visual pool can be acquired well with a high speed camera and the number of fibers in the top layer of the slurry can be determined from the plurality of inspection images.

In one embodiment, the detection device further comprises a water inlet mechanism having a water supply port in communication with the mixing chamber and a water discharge mechanism having a water return port, the visible chamber being in communication between the separation outlet and the water return port. Pure water can be provided in a mixing cavity of the mixing container through the water inlet mechanism, a separating agent and pure water form a separating agent aqueous solution with a preset volume in the mixing cavity, and graphite powder with a preset mass is added in the mixing cavity to form slurry, graphite particles and fibers can be arranged in layers in the slurry, the top layer of the slurry can be separated from the mixing cavity through the separating mechanism, the top layer of the slurry can flow through a visual cavity of a visual pool, in the process, an acquisition mechanism can acquire the number of fibers in the top layer of the slurry through a visual part, and after the number of fibers is detected, the top layer of the detected slurry can be collected and processed through the water draining mechanism. Thus, the separated top layer of the slurry can flow through the visual pool at a preset speed, and the acquisition mechanism can acquire the number of fibers in the top layer of the slurry through the visual part conveniently.

The foregoing description is only an overview of the present application, and is intended to be implemented in accordance with the teachings of the present application in order that the same may be more clearly understood and to make the same and other objects, features and advantages of the present application more readily apparent.

Drawings

Various other advantages and benefits will become apparent to those of ordinary skill in the art upon reading the following detailed description of the preferred embodiments. The drawings are only for purposes of illustrating the preferred embodiments and are not to be construed as limiting the application. Also, like reference numerals are used to designate like parts throughout the accompanying drawings. In the drawings:

Fig. 1 is a flow chart of a detection method according to an embodiment of the application.

Fig. 2 shows a schematic structural diagram of a detection device according to an embodiment of the present application.

Fig. 3 is a flow chart of a detection method according to another embodiment of the application.

Fig. 4 shows a schematic structural diagram of a detection device according to another embodiment of the present application.

Reference numerals:

10. a detection device;

110. A mixing vessel; 1101. a mixing chamber; 1102. a separation outlet;

120. a separation mechanism; 121. a drainage member; 1211. an air blowing port; 122. a gas supply member;

130. An acquisition mechanism;

140. A visual pool; 141. a visual part; 1401. a visual cavity;

151. A flow guiding pipe; 152. a valve;

160. an ultrasonic disperser;

171. A water inlet mechanism; 1711. a water supply port; 172. a drainage mechanism; 1721. a water return port; 173. a communicating pipe; 174. a blow-down pipe;

180. a stirring mechanism; 181. a motor; 182. a gear assembly; 183. stirring paddles;

20. Graphite particles;

30. A fiber;

40. A slurry; 41. a top layer; 42. a bottom layer.

Detailed Description

In order that the above objects, features and advantages of the application will be readily understood, a more particular description of the application will be rendered by reference to the appended drawings. In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present application. The present application may be embodied in many other forms than described herein and similarly modified by those skilled in the art without departing from the spirit of the application, whereby the application is not limited to the specific embodiments disclosed below.

In the description of the present application, it should be understood that, if any, these terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., are used herein with respect to the orientation or positional relationship shown in the drawings, these terms refer to the orientation or positional relationship for convenience of description and simplicity of description only, and do not indicate or imply that the apparatus or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore should not be construed as limiting the application.

Furthermore, the terms "first," "second," and the like, if any, are used for descriptive purposes only and are not to be construed as indicating or implying a relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defining "a first" or "a second" may explicitly or implicitly include at least one such feature. In the description of the present application, the terms "plurality" and "a plurality" if any, mean at least two, such as two, three, etc., unless specifically defined otherwise.

In the present application, unless explicitly stated and limited otherwise, the terms "mounted," "connected," "secured," and the like are to be construed broadly. For example, the two parts can be fixedly connected, detachably connected or integrated; can be mechanically or electrically connected; either directly or indirectly, through intermediaries, or both, may be in communication with each other or in interaction with each other, unless expressly defined otherwise. The specific meaning of the above terms in the present application can be understood by those of ordinary skill in the art according to the specific circumstances.

In the present application, unless expressly stated or limited otherwise, the meaning of a first feature being "on" or "off" a second feature, and the like, is that the first and second features are either in direct contact or in indirect contact through an intervening medium. Moreover, a first feature being "above," "over" and "on" a second feature may be a first feature being directly above or obliquely above the second feature, or simply indicating that the first feature is level higher than the second feature. The first feature being "under", "below" and "beneath" the second feature may be the first feature being directly under or obliquely below the second feature, or simply indicating that the first feature is less level than the second feature.

It will be understood that if an element is referred to as being "fixed" or "disposed" on another element, it can be directly on the other element or intervening elements may also be present. If an element is referred to as being "connected" to another element, it can be directly connected to the other element or intervening elements may also be present. The terms "vertical," "horizontal," "upper," "lower," "left," "right," and the like as used herein, if any, are for descriptive purposes only and do not represent a unique embodiment.

Through researches, the problems that the surface of the coated negative electrode plate is uneven and the like can be caused by the existence of fibers in the graphite powder. Therefore, it is desirable to provide a detection method capable of detecting impurities such as fibers in graphite powder so as to provide corresponding guidance for quality control of graphite powder.

In the related art, a small amount of graphite (e.g. 3 g) is added to a large amount of pure water (e.g. 25L) to realize effective dispersion of graphite particles and clear appearance of fiber in graphite, so that qualitative analysis of fiber in graphite can be performed, however, the detection method of graphite particles in the related art needs to consume a large amount of pure water.

In order to solve the problem that a large amount of pure water is consumed in the detection method of the graphite particles in the related art, the application designs the detection method and the detection device, which can utilize the aqueous solution of the separating agent to enable the fibers in the graphite powder and the graphite particles to be arranged in a layered manner, so that the fibers on the upper layer can be separated conveniently, the number of the fibers can be obtained, and the detection method can reduce the consumption of the pure water and reduce the detection cost.

The detection method and/or the detection device disclosed by the embodiment of the application can be used in the production of batteries, but are not limited to.

Fig. 1 is a flow chart of a detection method according to an embodiment of the application. Fig. 2 shows a schematic structural diagram of a detection device 10 according to an embodiment of the present application.

Referring to fig. 1 and 2, an embodiment of the present application provides a detection method for detecting a fiber 30 in graphite powder, the detection method comprising the following steps:

S10, mixing graphite powder with preset mass and a separating agent aqueous solution with preset volume to form slurry 40, so that the fiber 30 and graphite particles 20 in the graphite powder are layered, the fiber 30 is positioned on the top layer 41 of the slurry 40, and the graphite particles 20 are positioned on the bottom layer 42 of the slurry 40; wherein the aqueous separating agent has a density less than the density of the graphite particles 20 and greater than the density of the fibers 30.

The aqueous separating agent solution is an aqueous solution having a density greater than that of the fibers 30 and smaller than that of the graphite particles 20 and capable of layering the fibers 30 and the graphite particles 20, and it should be noted that the aqueous separating agent solution does not react with the fibers 30 and the graphite particles 20.

The separating agent aqueous solution comprises pure water and a separating agent which is easy to dissolve in the water, a certain mass of the separating agent is dissolved in a certain volume of the pure water to prepare the separating agent aqueous solution, and the density of the separating agent aqueous solution is smaller than that of the graphite particles 20 and larger than that of the fibers 30.

The separating agent may be selected according to the density condition that the aqueous separating agent solution has a density smaller than that of the graphite particles 20 and greater than that of the fibers 30, and may be a substance capable of satisfying the above density condition and readily soluble in water, for example, the separating agent may be an inorganic compound capable of satisfying the above density condition and readily soluble in water, and specifically, the separating agent may be a metal halide capable of satisfying the above density condition and readily soluble in water.

Conditions for selecting the separating agent may also be selected according to the appearance of the aqueous separating agent solution, for example, the appearance conditions include: the separating agent aqueous solution is a light-transmitting aqueous solution, and specifically, the appearance conditions include: the aqueous separating agent solution may be a colorless transparent solution. In this manner, the top layer 41 of slurry 40 is facilitated to be separated as desired.

The top layer 41 of the slurry 40 refers to a layer of solution of the slurry 40 on the top side of the bottom layer 42 and having the fibers 30 disposed therein, and the bottom layer 42 of the slurry 40 refers to a layer of solution of the slurry 40 on the bottom side of the top layer 41 and having the graphite particles 20 disposed therein.

Alternatively, a stirring method may be used to uniformly mix a preset mass of graphite powder and a preset volume of aqueous solution of a separating agent, and then a standing method may be used to layer the fibers 30 and the graphite particles 20 in the graphite powder.

S20, separating the top layer 41 of the slurry 40.

The top layer 41 of the slurry 40 may be separated by suction, the top layer 41 of the slurry 40 may be separated by drainage, and the top layer 41 of the slurry 40 may be separated by overflow. There is no particular limitation herein.

S30, the number of fibers 30 in the top layer 41 of the slurry 40 is obtained.

The top layer 41 of the separated slurry 40 may be passed through a filter to intercept the portion of fibers 30 and then the number of the portion of fibers 30 may be obtained, or the number of fibers 30 in the top layer 41 of the slurry 40 may be obtained in other ways.

The number of fibers 30 in the top layer 41 of the slurry 40 may be obtained by direct visual inspection, or the number of fibers 30 in the top layer 41 of the slurry 40 may be obtained by a camera or a microscope or the like. Illustratively, the microscope may be selected from a Kernel digital microscope, leica microscope system, or microscopic particulate analysis system (JOMESA).

Because the density of the separating agent aqueous solution is smaller than that of the graphite particles 20 and is larger than that of the fibers 30, after the preset mass of graphite powder and the preset volume of separating agent aqueous solution are mixed to form the slurry 40, the graphite powder can be deposited on the bottom layer 42 of the slurry 40 under the action of gravity due to the fact that the density of the separating agent aqueous solution is larger than that of the separating agent aqueous solution, the fibers 30 float on the top layer 41 of the slurry 40 due to the fact that the density of the separating agent aqueous solution is smaller than that of the separating agent aqueous solution, the fibers 30 and the graphite particles 20 are arranged in a layered mode, then the top layer 41 of the slurry 40 is separated, and the number of the fibers 30 in the top layer 41 of the slurry 40 is obtained.

In some embodiments, the aqueous separating agent solution is a colorless transparent solution.

That is, the appearance conditions include: the separating agent aqueous solution is colorless transparent solution.

The separating agent aqueous solution may be zinc chloride aqueous solution or potassium chloride aqueous solution, but may be other aqueous solutions capable of satisfying the above-mentioned appearance condition and density condition.

Because the aqueous solution of the separating agent is a colorless transparent solution, whether the fibers 30 and the graphite particles 20 in the slurry 40 are layered or not can be conveniently observed, so that the top layer 41 of the slurry 40 can be separated according to the requirement, and the operation convenience of the detection method of the application can be improved.

In some embodiments, the aqueous separating agent solution comprises an aqueous zinc chloride solution.

On the one hand, the zinc chloride aqueous solution is a colorless transparent aqueous solution, so that the top layer 41 of the slurry 40 can be conveniently separated according to the requirement, and the operation convenience of the detection method of the application can be improved. On the other hand, by dissolving zinc chloride in a certain amount of pure water, the zinc chloride aqueous solution satisfying the density condition that the density of the zinc chloride aqueous solution is smaller than that of the graphite particles 20 and larger than that of the fibers 30 can be easily prepared, and the convenience of detection can be improved. In addition, the zinc chloride aqueous solution is nontoxic and non-corrosive, so that the safety of the detection method can be improved, and the pollution degree of the subsequent water treatment of the detection method can be reduced.

In some embodiments, the zinc chloride aqueous solution has a density of 1.5g/cm ³-1.8g/cm³.

Illustratively, the zinc chloride aqueous solution has a density of 1.5g/cm ³、1.6g/cm³、1.7g/cm³ or 1.8g/cm ³.

Typically, the density of the fiber 30 is in the range of 0.91g/cm ³-1.54g/cm³, the density of the graphite particles 20 is in the range of 2.09g/cm ³-2.23g/cm³, and based on this, the density of the prepared zinc chloride aqueous solution is selected in a proper range, for example, 1.5g/cm ³-1.8g/cm³, so that the density of the prepared zinc chloride aqueous solution is greatly different from that of the graphite particles 20, which is beneficial to better utilize the zinc chloride aqueous solution to enable the graphite particles 20 to be deposited on the bottom layer 42 of the slurry 40 under the action of gravity, and further, the zinc chloride aqueous solution can be better utilized to enable the fiber 30 and the graphite particles 20 to be layered, so as to separate the top layer 41 of the slurry 40 later, and obtain the number of the fiber 30 in the top layer 41 of the slurry 40, thereby improving the reliability of the detection method of the application.

In some embodiments, the preset mass is a and the preset volume is V, wherein the preset mass and preset volume satisfy the following conditions: v/a is more than or equal to 1.5ml/g.

Illustratively, V/a is 1.5ml/g, 2.5ml/g, 3.5ml/g, etc.

It will be appreciated that the graphite particles 20 are in grams of mass and the predetermined volume is in milliliters of volume.

Wherein a is 50g-100g, and V is 150ml-250ml. Illustratively, a is 50g, 75g or 100g and V may be 150ml, 200ml or 250ml.

In order to separate the fibers 30 and the graphite particles 20 better, it is necessary to mix a predetermined mass of graphite powder with a sufficient volume of the aqueous separating agent solution so that the fibers 30 and the graphite particles 20 can be spaced apart within the slurry 40 to separate the fibers 30 at the top layer 41 of the slurry 40 to obtain the number of fibers 30, and thus, the predetermined mass and the predetermined volume need to satisfy the following conditions: v/a is more than or equal to 1.5ml/g.

In some embodiments, the preset mass and preset volume satisfy the following conditions: v/a is less than or equal to 1.5ml/g and less than or equal to 3ml/g.

Illustratively, V/a is 1.5ml/g, 2.5ml/g, 3ml/g, etc. Specifically, a is 50g, 60g, 70g, 80g, 90g or 100g, and V may be 150ml, 160ml, 170ml, 180ml, 190ml, 200ml, 210ml, 220ml, 230ml, 240ml or 250ml.

Thus, the fiber 30 and the graphite particles 20 can be well separated in the slurry 40 by a certain distance, so that the fiber 30 positioned on the top layer 41 of the slurry 40 is conveniently separated to obtain the number of the fibers 30, and the volume of the separating agent aqueous solution can be reduced under the condition that the quality of the graphite particles 20 is inconvenient, so that the detection cost of the detection method is reduced.

In some embodiments, the step S20 of separating the top layer 41 of the slurry 40 specifically includes:

s21, separating the top layer 41 of the slurry 40 in a drainage mode.

The top layer 41 of the slurry 40 is separated, for example by drainage means, in order to obtain the amount of fibres 30 in the top layer 41 of the slurry 40.

In some embodiments, referring to fig. 3, before the step S20 of separating the top layer 41 of the slurry 40, the detection method further includes:

S11, adding a flocculating agent into the slurry 40.

The flocculant may be an inorganic flocculant such as polyaluminum chloride, or an organic flocculant such as polyacrylamide. The flocculant can be selected from water-soluble flocculant and water-insoluble flocculant, and specifically, the flocculant can be selected according to actual needs.

The flocculant is capable of interacting with the graphite particles 20 in the slurry 40 to form larger flocks, thereby flocculating and precipitating the graphite particles 20, and the flocculant may be utilized to better and more quickly layer the fibers 30 and the graphite particles 20, facilitating the subsequent better separation of the top layer 41 of the slurry 40, so as to obtain the number of fibers 30 in the top layer 41 of the slurry 40.

In some embodiments, the flocculant comprises a water-soluble flocculant.

The water-soluble flocculant is selected to provide good dissolution of the flocculant in water so that the flocculant contacts the graphite particles 20 in the slurry 40 more and faster, and to better flocculate and precipitate the graphite particles 20, thereby facilitating a better layering of the fibers 30 and the graphite particles 20, and facilitating a subsequent better separation of the top layer 41 of the slurry 40 so as to obtain the amount of fibers 30 in the top layer 41 of the slurry 40.

In some embodiments, the mass of water in the aqueous separating agent solution is b, the mass of flocculant added is greater than or equal to 0.002b, and the mass units of graphite particles 20 and flocculant are grams.

For example, the mass of water in the aqueous separating agent solution is b, and the mass of flocculant added is 0.003b, 0.0025b, 0.00375 or 0.004b. Illustratively, the mass of water in the aqueous separating agent solution is 800g and the mass of flocculant is 3g.

To better bring the flocculant into more and faster contact with the graphite particles 20 in slurry 40, sufficient flocculant may be added based on the mass of water in the aqueous separating agent solution, e.g., b, with the mass of flocculant added being greater than or equal to 0.002b, where the mass units of graphite particles 20 and flocculant are grams.

In some embodiments, the mass of water in the aqueous separating agent solution is b and the mass of flocculant added is 0.0025b to 0.01b.

Specifically, the mass of the flocculant added is 0.0025b-0.004b. More specifically, the mass of the flocculant added is 0.003b to 0.0038b. Illustratively, the mass of water in the aqueous separating agent solution is b, and the mass of flocculant added is 0.003b, 0.0033b, 0.0036b, or 0.0038b. The mass of water in the separating agent aqueous solution was 900g, and the mass of the flocculant was 3g.

In this manner, on the one hand, the flocculant is allowed to contact the graphite particles 20 in the slurry 40 more and faster, and the graphite particles 20 are better flocculated and precipitated, thereby facilitating better layering of the fibers 30 and the graphite particles 20, and also facilitating better separation of the top layer 41 of the slurry 40 to obtain the amount of fibers 30 in the top layer 41 of the slurry 40. On the other hand, the cost of the flocculant can be reasonably controlled.

and S12, treating the slurry 40 added with the flocculating agent by adopting a centrifugal separation mode.

The centrifugal separation method can be used for layering the fibers 30 and the graphite particles 20 more quickly and better, so that the top layer 41 of the slurry 40 can be separated better, and the number of the fibers 30 in the top layer 41 of the slurry 40 can be obtained.

s13, mixing graphite powder, a separating agent aqueous solution and a flocculating agent in a stirring mode.

Specifically, step S13 is located before step S12.

The graphite powder, the aqueous separating agent solution, and the flocculant may be sufficiently dispersed to facilitate the interaction of the flocculant with the graphite particles 20 to flocculate and precipitate the graphite particles 20, and the aqueous separating agent solution may be better utilized to layer the fibers 30 and the graphite particles 20 (e.g., the fibers 30 and the graphite particles 20 may be more quickly layered by centrifugal separation) to subsequently obtain the number of fibers 30 in the top layer 41 of the slurry 40.

In some embodiments, the step S13 of mixing the graphite powder, the aqueous separating agent solution and the flocculant by stirring specifically includes:

S131, mixing graphite powder, a separating agent aqueous solution and a flocculating agent for a first preset time at a first preset stirring speed.

For example, the first preset time may be 1 minute to 3 minutes, for example, the first preset time may be 1 minute, 2 minutes, or 3 minutes.

S132, mixing the graphite powder, the separating agent aqueous solution and the flocculating agent for a second preset time at a second preset stirring speed.

For example, the second preset time may be 9 minutes to 12 minutes, for example, the second preset time may be 9 minutes, 10 minutes, 11 minutes, or 12 minutes.

Wherein the first preset stirring speed is smaller than the second preset stirring speed.

Specifically, the first preset stirring speed is less than or equal to 200rpm, and the second preset stirring speed is greater than 200rpm and less than or equal to 500rpm.

The first preset stirring speed may be 100rpm or 200rpm, and the stirring speed may be slowly increased to the first preset stirring speed for a first preset time. Illustratively, the first preset agitation speed is 200rpm, and the agitation speed may be increased by 50rpm every 1 minute until the first preset agitation speed is reached.

The second preset stirring speed may be 400rpm or 500rpm, and the stirring speed may be slowly increased to the second preset stirring speed for the second preset time. Illustratively, the second preset agitation speed is 500rpm, and the agitation speed may be increased by 50rpm every 1 minute until the agitation speed is increased from the first preset agitation to the second preset agitation speed.

Firstly, mixing graphite powder, a separating agent aqueous solution and a flocculating agent for a first preset time at a small stirring speed, so that the probability of flying phenomenon of the graphite powder is reduced; and mixing the graphite powder, the aqueous solution of the separating agent and the flocculating agent for a second preset time at a larger stirring speed, so that the flocculating agent is in contact with the graphite particles 20 sufficiently, the interaction of the flocculating agent and the graphite particles 20 is facilitated, the graphite particles 20 are flocculated and precipitated, and the fibers 30 and the graphite particles 20 can be arranged in a layered manner by utilizing the aqueous solution of the separating agent better, so that the number of the fibers 30 in the top layer 41 of the slurry 40 can be acquired later.

and S14, adding a surfactant into the slurry 40.

Alternatively, the surfactant may be a readily water-soluble surfactant or a water-soluble surfactant, such as potassium laureth phosphate, polysorbate, or X-3204 dispersant.

Because one end of the surfactant is a hydrophilic group and the other end is a hydrophobic group, the hydrophobic group of the surfactant can be utilized to adsorb graphite particles 20 in the graphite powder, and further the hydrophilic group of the surfactant can be utilized to ensure that the graphite particles 20 are dispersed more uniformly in the separating agent aqueous solution, thereby being beneficial to better separating out fibers 30 doped among the graphite particles 20, improving the separation effect of the fibers 30 and the graphite particles 20, and further being beneficial to more accurately detecting the number of the fibers 30 by using the detection method.

Optionally, step S14 may also be located before step S13, and step S13 is located before step S12, so that step S13 of mixing graphite powder, the aqueous solution of the separating agent and the flocculant by stirring specifically includes: mixing graphite powder, a separating agent aqueous solution, a flocculating agent and a surfactant in a stirring manner. The step S12 of treating the slurry 40 to which the flocculant is added by centrifugal separation specifically includes: the slurry 40 with the flocculant and surfactant added is treated by centrifugation.

The graphite powder, the separating agent aqueous solution, the flocculating agent and the surfactant can be fully mixed in a stirring manner, so that the dispersing effect of the surfactant can be improved, the separating effect of the fiber 30 and the graphite particles 20 can be improved, and the number of the fiber 30 can be detected by using the detection method more accurately.

In some embodiments, the predetermined mass is a and the added surfactant is c, where 0.02 a.ltoreq.c.ltoreq.0.07 a, and the graphite particles 20 and the surfactant are each gram.

For example, c is 0.02a, 0.03a, 0.04a, 0.05a, 0.06a, or 0.07a, and the preset mass is 100g, and the mass of the surfactant added is 2g, 3g, 4g, 5g, 6g, or 7g, for example.

According to the preset mass, the mass of the added surfactant is set in a proper range, so that the hydrophilic groups of the surfactant can be better utilized to uniformly disperse the graphite particles 20 in the aqueous solution of the separating agent, the separation effect of the fibers 30 and the graphite particles 20 can be improved, and the number of the fibers 30 can be accurately detected by the detection method.

In some embodiments, 0.03 a.ltoreq.c.ltoreq.0.06 a.

For example, c is 0.03a, 0.04a, 0.05a, or 0.06a, and the preset mass is 100g, and the mass of the added surfactant is 3g, 4g, 5g, or 6g, for example.

Thus, the graphite particles 20 can be uniformly dispersed in the separating agent aqueous solution by utilizing the surfactant with proper dosage, the separating effect of the fiber 30 and the graphite particles 20 is improved, the number of the fibers 30 can be detected by utilizing the detection method more accurately, and the use cost of the surfactant can be reasonably controlled.

In some embodiments, the step S30 of obtaining the number of fibers 30 in the top layer 41 of the slurry 40 specifically includes:

s31, enabling the top layer 41 of the separated slurry 40 to flow through the visible pool 140 at a preset speed.

The top layer 41 of the slurry 40 may flow through the visual pool 140 under the action of gravity, where the preset speed is gt (g is gravity acceleration, t is the time when the top layer 41 of the slurry 40 falls), or the top layer 41 of the slurry 40 may flow through the visual pool 140 at the preset speed by a suction pump, which is not limited herein.

S32, acquiring a plurality of detection images of the fibers 30 flowing through the visual pool 140, and determining the number of the fibers 30 in the top layer 41 of the slurry 40 according to the plurality of detection images.

A plurality of sensed images of the fibers 30 flowing through the visual pool 140 may be acquired and the number of fibers 30 in the top layer 41 of the slurry 40 may be determined based on the plurality of sensed images. Specifically, the image recognition analysis system may be utilized to process the plurality of inspection images and determine the number of fibers 30 within the top layer 41 of the slurry 40. Thus, the labor cost of manual counting can be reduced, and the number of fibers 30 in the graphite powder can be detected more accurately and efficiently by using the detection method.

Referring to fig. 2 and 4, an embodiment of the present application provides a detection apparatus 10, where the detection apparatus 10 is applied to the detection method of any one of the above embodiments, and the detection apparatus 10 includes a mixing container 110, a separating mechanism 120, and an obtaining mechanism 130.

The mixing vessel 110 has a mixing chamber 1101 for mixing graphite powder and an aqueous solution of a separating agent, a separating mechanism 120 is provided on the mixing vessel 110 for separating the top layer 41 of the slurry 40 from the mixing chamber 1101, and an acquisition mechanism 130 is provided on one side of the mixing vessel 110 for acquiring the number of fibers 30 in the top layer 41 of the slurry 40.

The mixing vessel 110 may be a tank, such as a centrifuge tank, a stirred tank, or a centrifuge stirred tank.

The separation mechanism 120 may include a suction pump coupled to the mixing vessel 110 that may be used to draw the top layer 41 of the slurry 40 from the mixing chamber 1101; the separation mechanism 120 may also include a flow guide 121 through which the top layer 41 of slurry 40 is separated from the mixing chamber 1101 by flow guide 121. There is no particular limitation herein.

The acquisition mechanism 130 may be a microscope or camera, but may be any other mechanism capable of acquiring the number of fibers 30 in the top layer 41 of the slurry 40.

When the detection device 10 is used, graphite powder and a separating agent aqueous solution can be mixed by the mixing container 110 to obtain the slurry 40, the slurry 40 in the mixing cavity 1101 of the mixing container 110 can be kept stand for layering or layered in a centrifugal mode, so that the fibers 30 and the graphite particles 20 are layered, then the top layer 41 of the slurry 40 is separated by the separating mechanism 120, the number of the fibers 30 in the top layer 41 of the slurry 40 is obtained by the obtaining mechanism 130, the number of the fibers 30 in the graphite powder with a certain mass can be obtained, and the corresponding quality control of the graphite powder is facilitated.

In some embodiments, the top of the sidewall of the mixing vessel 110 is provided with a separation outlet 1102 in communication with the mixing chamber 1101, and the separation mechanism 120 comprises a flow guide 121, the flow guide 121 being adapted to guide the top layer 41 of the slurry 40 out towards the separation outlet 1102.

The drainage member 121 refers to a member capable of guiding the top layer 41 of the slurry 40 to flow out towards the separation outlet 1102. Drainage by blowing may be provided, overflow structures or the like may be provided which guide the top layer 41 of the slurry 40 out of the separation outlet 1102.

The graphite powder and the separating agent aqueous solution are mixed to obtain the slurry 40, and after the fibers 30 are positioned on the top layer 41 of the slurry 40 and the graphite particles 20 are positioned on the bottom layer 42 of the slurry 40, the top layer 41 of the slurry 40 can be guided to flow out towards the separating outlet 1102 through the drainage member 121, so that the number of the fibers 30 in the top layer 41 of the slurry 40 can be conveniently obtained.

In some embodiments, the separation mechanism 120 further includes an air supply member 122 coupled to the flow guide member 121, the air supply member 122 having an air supply port, the flow guide member 121 having an air blow port 1211 disposed toward the separation outlet 1102, the air blow port 1211 being in communication with the separation outlet 1102 and the air supply port, respectively.

The air-blowing port 1211 is being disposed toward the separation outlet 1102, and the air-blowing port 1211 may also be disposed obliquely toward the separation outlet 1102, such as with the axial direction of the air-blowing port 1211 disposed at an angle to the axial direction of the separation outlet 1102 and the gravitational direction of the mixing container 110, respectively.

Specifically, the drainage member 121 is disposed on a side wall of the mixing vessel 110 opposite to the separation outlet 1102 at a distance.

Gases which do not react with the substances in the mixing chamber 1101, such as air or inert gases, can be introduced into the mixing chamber 1101 through the gas supply opening and the gas blowing opening 1211 of the gas supply member 122, and the gas blown into the mixing chamber 1101 from the gas blowing opening 1211 is arranged towards the separation outlet 1102, so that the gases blown into the mixing chamber 1101 from the gas blowing opening 1211 can flow towards the separation outlet 1102, and further drive the top layer 41 of the slurry 40 to flow towards the separation outlet 1102, and further the top layer 41 of the slurry 40 can be separated from the mixing chamber 1101, so that the number of fibers 30 in the top layer 41 of the slurry 40 can be obtained later.

In some embodiments, the detection device 10 further comprises a visual pool 140 located outside the mixing vessel 110 and on the side of the acquisition mechanism 130, the visual pool 140 having a visual cavity 1401 communicating with the separation outlet 1102, the visual pool 140 being located on the underside of the separation outlet 1102 in a direction parallel to the top of the mixing vessel 110 pointing towards the bottom thereof, the visual pool 140 comprising a visual portion 141 for viewing the fibers 30.

Since the visual pool 140 is located at the lower side of the separation outlet 1102, after the top layer 41 of the slurry 40 is separated from the mixing chamber 1101, the slurry can slowly flow into the visual pool 140 by gravity, the fibers 30 flowing into the visual pool 140 can be observed by the visual portion 141, and the number of the fibers 30 in the top layer 41 of the slurry 40 can be obtained by the obtaining mechanism 130.

In some embodiments, the detection device 10 further includes a flow guide 151 and an ultrasonic disperser 160, one end of the flow guide 151 is communicated with the separation outlet 1102, the other end of the flow guide 151 is communicated with the visual cavity 1401, and the ultrasonic disperser 160 is disposed on the flow guide 151.

After the top layer 41 of the slurry 40 is separated from the mixing chamber 1101 and before the top layer 41 of the slurry 40 flows into the visual pool 140, the fibers 30 in the top layer 41 of the slurry 40 can be fully dispersed in the top layer 41 of the slurry 40 by the ultrasonic disperser 160 arranged on the flow guide 151 through the flow guide 151, so that the condition that the fibers 30 are clustered is reduced, and the number of the fibers 30 in the top layer 41 of the slurry 40 is better obtained.

In some embodiments, a valve 152 is provided at the separation outlet 1102 or on the draft tube 151.

Valve 152 may be closed first to mix the graphite powder and the aqueous separating agent to obtain slurry 40, and after layering of fibers 30 and graphite particles 20, valve 152 may be opened so that top layer 41 of slurry 40 is separated from separation outlet 1102, facilitating subsequent acquisition of the number of fibers 30 in top layer 41 of slurry 40.

In some embodiments, the acquisition mechanism 130 includes a high-speed camera directed toward the viewable portion 141.

A plurality of sensed images of the fibers 30 flowing into the visual pool 140 can be well acquired with a high speed camera and facilitate determining the number of fibers 30 in the top layer 41 of the slurry 40 based on the plurality of sensed images.

Specifically, the acquisition mechanism 130 further includes an image recognition analysis system electrically coupled to the high speed camera for processing the plurality of inspection images and determining the number of fibers 30 within the top layer 41 of the slurry 40.

In some embodiments, the detection apparatus 10 further includes a stirring mechanism 180, where the stirring mechanism 180 includes a motor 181, a gear assembly 182 connected to the motor 181, and a stirring paddle 183 coaxially disposed with one gear of the gear assembly 182, and an end of the stirring paddle 183 remote from the gear assembly 182 extends into the mixing chamber 1101.

The motor 181 can drive the gear of the gear assembly 182 to rotate, so as to drive the stirring paddle 183 to rotate, and stir the materials in the mixing cavity 1101, for example, graphite powder, a separating agent aqueous solution, a flocculating agent and the like can be mixed in a stirring manner.

In some embodiments, the detecting device 10 further includes a controller (not shown) electrically connected to the motor 181, the controller being configured to control the output of the motor 181 to rotate the stirring paddle 183 at a first preset stirring speed for a first preset time and then at a second preset stirring speed for a second preset time.

In some embodiments, the detection device 10 further includes a water inlet mechanism 171 and a water outlet mechanism 172, the water inlet mechanism 171 having a water supply port 1711 in communication with the mixing chamber 1101, the water outlet mechanism 172 having a water return port 1721, the visual chamber 1401 being in communication between the separation outlet 1102 and the water return port 1721.

Specifically, the detection device 10 further includes a communication pipe 173 that communicates between the visible chamber 1401 and the return water port 1721.

In this manner, pure water may be provided to the mixing chamber 1101 of the mixing vessel 110 through the water inlet mechanism 171, a predetermined volume of the aqueous solution of the separating agent and the pure water may be formed in the mixing chamber 1101, and a predetermined mass of graphite powder may be added to the mixing chamber 1101 to form the slurry 40, the graphite particles 20 and the fibers 30 may be layered within the slurry 40, the top layer 41 of the slurry 40 may be separated from the mixing chamber 1101 through the separating mechanism 120, the top layer 41 of the slurry 40 may be caused to flow through the vision chamber 1401 of the vision cell 140, during which the obtaining mechanism 130 may obtain the number of the fibers 30 in the top layer 41 of the slurry 40 through the vision portion 141, and after the number of the fibers 30 is detected, the detected top layer 41 of the slurry 40 may be collected and processed through the water discharge mechanism 172. In this manner, the separated top layer 41 of the slurry 40 may be caused to flow through the visual cell 140 at a predetermined speed, so that the obtaining mechanism 130 may obtain the number of fibers 30 in the top layer 41 of the slurry 40 through the visual portion 141, for example, a plurality of detected images of the fibers 30 flowing through the visual cell 140 may be captured by a high-speed camera, and the plurality of detected images may be processed by an image recognition analysis system to determine the number of fibers 30 in the top layer 41 of the slurry 40.

In other embodiments, the detection apparatus 10 further includes a drain 174, and a side of the viewing chamber 1401 remote from the separation outlet 1102 is in communication with the drain 174.

In this manner, the top layer 41 of the slurry 40 may also be flowed through the viewing chamber 1401 of the viewing cell 140 to facilitate capturing a plurality of inspection images of the fibers 30 flowing through the viewing cell 140 using a high speed camera, and an image recognition analysis system may be used to process the plurality of inspection images and determine the number of fibers 30 within the top layer 41 of the slurry 40.

Test example 1

In order to examine the applicability of the detection method of the present application, the case where the graphite powder includes the fiber-free graphite and the fibers 30 is described as an example, and in the case of the same quality of the fiber-free graphite, the same type and the same number of fibers 30 are selected, and in the case where the densities of the aqueous solutions of the separating agents are different, the detection of the aqueous solutions of the separating agents of different densities is performed, respectively. Specifically, 800ml of pure water is injected into a mixing container 110 (centrifugal stirring tank) by utilizing a water inlet mechanism 171, zinc chloride powder with different quality is added, and after stirring is carried out uniformly, separating agent aqueous solutions with different densities are obtained respectively, 400g of fiber-free graphite, 3g of flocculating agent and 20g of surfactant (the surfactant is selected from X-3204 dispersing agent), 30 fibers 30 (the fibers can be first type fibers, the first type fibers are ribbon fibers and are white and circular cylindrical, the length of the first type fibers is 1000 microns, the diameter of the first type fibers is 25 microns) are added, mixing stirring is carried out, the stirring speed is slowly increased to 200rpm within 0-3 minutes, then slowly increased to 500rpm, stirring is continued for 12 minutes, after stirring is completed, centrifugal treatment is carried out on the substances in the mixing container 110, the fibers 30 and the graphite particles 20 are layered, the top layer 41 of the slurry 40 is separated, and the number of the fibers 30 in the top layer 41 of the slurry 40 is obtained. The results of the various types of aqueous solutions were as follows in table 1:

TABLE 1

Wherein the detection rate is the percentage of the number of the detected fibers to the number of the fibers actually contained in the graphite powder. The contrast material is white sugar, sodium citrate, ammonium sulfate or ammonium acetate.

As described above, in the related art, a small amount of graphite (e.g., 3 g) was added to a large amount of pure water (e.g., 25L) to achieve effective dispersion of the graphite particles 20 and the morphology of the fibers in the graphite was clearly seen, and in the case where the quality of the fiber-free graphite and the quality of the pure water were the same as those of examples 1 to 4 of the present application, the detection rate of the fibers in comparative example 6 was zero, and it was apparent that in comparative example 6, the graphite particles 20 could not be effectively dispersed due to the smaller amount of pure water, thereby affecting the detection of the fibers 30, and it was also reversely verified that a large amount of pure water was added to the graphite to achieve effective dispersion of the graphite particles 20; in comparative examples 1 to 6, the density of the aqueous solution was too small, less than 1.4g/cm ³, resulting in easy deposition of the fibers on the bottom layer of the aqueous solution, which in turn resulted in difficulty in separation of the fibers 30 from the graphite particles 20, which in turn resulted in lower detection rates of comparative examples 1 to 6; compared with comparative examples 1-6, the detection method provided by the application can greatly reduce the consumption of pure water, has higher detection rate, and especially can be more than 80% and even more than 90% when the density of the zinc chloride aqueous solution is 1.5g/cm ³-1.8g/cm³, so that the detection method provided by the application has higher accuracy, can be well applied to graphite powder in actual production, can well control the quality of the graphite powder, and can be used for reducing the problem that the surface of a negative electrode plate coated with the graphite powder is uneven.

Test example two

In order to examine the applicability of the detection method of the present application to different types of fibers, in this test embodiment, the graphite powder material includes fiber-free graphite and fibers, and under the condition of fiber-free graphite of the same quality, different types of fibers are selected, and three groups of detection of different fiber concentrations are respectively performed for each type of fibers. Specifically, 800ml of pure water is injected into a mixing container 110 (centrifugal stirring tank) by utilizing a water inlet mechanism 171, 1kg of zinc chloride powder is added, a separating agent aqueous solution is obtained after uniform stirring, 500g of fiber-free graphite, 3g of flocculating agent and 20g of surfactant (the surfactant is selected from X-3204 dispersing agent), 20, 30 or 40 fibers (the fibers can be second type fibers or third type fibers, wherein the second type fibers are ton package fibers, are transparent and flat, the length of the second type fibers is 1000 microns, the diameter of the second type fibers is 20 microns, the third type fibers are filter core fibers, are white and round cylindrical, the length of the third type fibers is 1000 microns, the diameter of the third type fibers is 15 microns) are added, the mixing stirring is carried out, the stirring speed is slowly increased to 200rpm within 0-3 minutes, then slowly increased to 500rpm, stirring is continued for 12 minutes, after the stirring is completed, the materials in the mixing container 110 are subjected to centrifugal treatment, the fibers and graphite particles 20 are layered, the fibers are separated from the slurry 40, and the number of the top layer 40 of the fibers in the top layer 41 is obtained. The results of the measurements of the different fiber concentrations and the different types of fibers are shown in Table 2 below:

TABLE 2

Wherein the detection rate is the percentage of the number of the detected fibers to the number of the fibers actually contained in the graphite powder.

From the above table 2, it can be seen that, by using the detection method of the present application, under the condition of the same quality of fiber-free graphite, the detection of different fiber concentrations is performed respectively, and the detection rate is greater than 90%, so that the detection method of the present application has high accuracy, and can be well applied to the graphite powder in actual production, so as to well perform corresponding quality control on the graphite powder, and reduce the problem of uneven surface of the negative electrode plate coated with the graphite powder.

The technical features of the above-described embodiments may be arbitrarily combined, and all possible combinations of the technical features in the above-described embodiments are not described for brevity of description, however, as long as there is no contradiction between the combinations of the technical features, they should be considered as the scope of the description.

The above examples illustrate only a few embodiments of the application, which are described in detail and are not to be construed as limiting the scope of the claims. It should be noted that it will be apparent to those skilled in the art that several variations and modifications can be made without departing from the spirit of the application, which are all within the scope of the application. Accordingly, the scope of protection of the present application is to be determined by the appended claims.

Claims

1. A detection method for detecting fibers in graphite powder; the detection method is characterized by comprising the following steps:

Mixing graphite powder with preset mass and a separating agent aqueous solution with preset volume to form slurry, so that the fibers and graphite particles in the graphite powder are layered, the fibers are positioned on the top layer of the slurry, and the graphite particles are positioned on the bottom layer of the slurry; wherein the separating agent aqueous solution has a density less than the density of the graphite particles and greater than the density of the fibers;

Separating the top layer of the slurry;

The number of fibers in the top layer of the slurry is obtained.

2. The method according to claim 1, wherein the aqueous separating agent solution is a colorless transparent solution.

3. The method of claim 2, wherein the aqueous separating agent comprises an aqueous zinc chloride solution.

4. The method according to claim 3, wherein the aqueous zinc chloride solution has a density of 1.5g/cm ³-1.8g/cm³.

5. The method of claim 1, wherein the predetermined mass is a and the predetermined volume is V, wherein the predetermined mass and the predetermined volume satisfy the following condition: v/a is more than or equal to 1.5ml/g.

6. The method of claim 5, wherein the predetermined mass and the predetermined volume satisfy the following conditions: v/a is less than or equal to 1.5ml/g and less than or equal to 3ml/g.

7. The method according to any one of claims 1 to 6, wherein said separating the top layer of the slurry comprises:

And separating the top layer of the slurry by adopting a drainage mode.

8. The method of any one of claims 1-6, wherein prior to separating the top layer of slurry, the method further comprises:

a flocculant is added to the slurry.

9. The method of detection of claim 8, wherein the flocculant comprises a water-soluble flocculant.

10. The method according to claim 8, wherein the mass of water in the aqueous solution of the separating agent is b, the mass of the flocculant added is 0.002b or more, and the mass units of the graphite particles and the flocculant are g.

11. The method according to claim 10, wherein the mass of water in the aqueous solution of the separating agent is b, and the mass of the flocculant added is 0.0025b to 0.01b.

12. The method of detecting according to claim 8, wherein prior to separating the top layer of slurry, the method further comprises:

The slurry added with the flocculant is treated by centrifugal separation.

13. The method of detecting according to claim 8, wherein prior to separating the top layer of slurry, the method further comprises:

and mixing the graphite powder, the separating agent aqueous solution and the flocculating agent in a stirring mode.

14. The method according to claim 13, wherein the mixing of the graphite powder, the aqueous separating agent solution and the flocculant by stirring comprises:

mixing the graphite powder, the aqueous solution of the separating agent and the flocculant for a first preset time at a first preset stirring speed;

Mixing the graphite powder, the aqueous solution of the separating agent and the flocculant for a second preset time at a second preset stirring speed;

15. The method of any one of claims 1-6, wherein prior to separating the top layer of slurry, the method further comprises:

A surfactant is added to the slurry.

16. The method according to claim 15, wherein the preset mass is a and the mass of the surfactant added is c;

Wherein c is more than or equal to 0.02a and less than or equal to 0.07a, and the mass units of the graphite particles and the surfactant are grams.

17. The method of claim 16, wherein 0.03 a.ltoreq.c.ltoreq.0.06 a.

18. The method according to any one of claims 1 to 6, wherein the obtaining the number of the fibers in the top layer of the slurry specifically comprises:

flowing the separated top layer of the slurry through a visual pool at a preset speed;

A plurality of detected images of the fibers flowing through the visual pool are acquired, and the number of fibers in the top layer of the slurry is determined based on the plurality of detected images.

19. A test device for use in a test method according to any one of claims 1 to 18, the test device comprising:

a mixing vessel having a mixing chamber for mixing the graphite powder and the aqueous solution of the separating agent;

A separation mechanism provided on the mixing vessel for separating a top layer of the slurry from the mixing chamber; and

And the acquisition mechanism is arranged on one side of the mixing container and is used for acquiring the number of the fibers in the top layer of the slurry.

20. The device according to claim 19, wherein the top of the side wall of the mixing vessel is provided with a separate outlet communicating with the mixing chamber;

The separation mechanism comprises a flow guide for guiding the top layer of slurry out towards the separation outlet.

21. The test device of claim 20, wherein the separation mechanism further comprises an air supply member coupled to the flow guide member, the air supply member having an air supply port;

The drainage piece is provided with an air blowing port which is arranged towards the separation outlet and is respectively communicated with the separation outlet and the air supply port.

22. The test device of claim 20, further comprising a visual well outside the mixing vessel and to one side of the acquisition mechanism;

the visual pool is provided with a visual cavity communicated with the separation outlet, and is positioned at the lower side of the separation outlet along the direction parallel to the top of the mixing container and pointing to the bottom of the mixing container;

The visualization pool includes a visualization portion for viewing the fibers.

23. The detection apparatus according to claim 22, characterized in that the detection apparatus further comprises:

one end of the flow guide pipe is communicated with the separation outlet, and the other end of the flow guide pipe is communicated with the visible cavity; and

The ultrasonic disperser is arranged on the guide pipe.

24. The detection apparatus according to claim 22, wherein the acquisition mechanism includes a high-speed camera directed toward the viewing portion.

25. The test device of claim 22, wherein the test device further comprises:

a water inlet mechanism which is provided with a water supply port communicated with the mixing cavity; and

The drainage mechanism is provided with a water return port, and the visible cavity is communicated between the separation outlet and the water return port.