Detection method and detection device

Abstract

A detection method and a detection device (10). The detection method is used for detecting fibers (30) in a graphite powder. The detection method comprises: mixing a preset mass of a graphite powder and a preset volume of an aqueous solution of a separating agent, so as to form a slurry (40), such that fibers (30) and graphite particles (20) in the graphite powder are arranged in layers, with the fibers (30) being located at the top layer (41) of the slurry (40), and the graphite particles (20) being located at the bottom layer (42) of the slurry (40), wherein the density of the aqueous solution of a separating agent is less than the density of the graphite particles (20) and is greater than the density of the fibers (30); separating out the top layer (41) of the slurry (40); and obtaining the number of fibers in the top layer (41) of the slurry (40).

Description

Detection method and detection device Cross-reference to related applications

[0001] This application is based on Chinese Patent Application No. 202410451985.3, filed on April 16, 2024, entitled "Detection method and detection device", which is incorporated by reference in its entirety. TECHNICAL FIELD

[0002] The present application relates to the technical field of batteries, in particular to a detection method and a detection device. BACKGROUND

[0003] The negative electrode material of a battery includes graphite powder, and the quality of the graphite powder is a crucial factor for the quality control of the battery. Therefore, it is necessary to detect impurities in the graphite powder as a basis for quality control of the graphite powder.

[0004] However, the detection method of the related art graphite particles requires a large amount of pure water. SUMMARY

[0005] Therefore, it is necessary to provide a detection method and a detection device to solve the problem that the detection method of the related art graphite particles requires a large amount of pure water.

[0006] According to a first aspect of the present application, a detection method for detecting fibers in graphite powder is provided, the detection method comprising: mixing a predetermined mass of graphite powder and a predetermined volume of a water solution of a separating agent to form a slurry, so that the fibers and graphite particles in the graphite powder are arranged in layers, and the fibers are located in the top layer of the slurry and the graphite particles are located in the bottom layer of the slurry; wherein the density of the water solution of the separating agent is less than the density of the graphite particles and greater than the density of the fibers; separating the top layer of the slurry; and obtaining the number of fibers in the top layer of the slurry.

[0007] In the technical solution of the present application, since the density of the water solution of the separating agent is less than the density of the graphite particles and greater than the density of the fibers, after the predetermined mass of graphite powder and the predetermined volume of the water solution of the separating agent are mixed to form a slurry, the graphite powder can be deposited in the bottom layer of the slurry under the action of gravity because its density is greater than the density of the water solution of the separating agent, while the fibers will float in the top layer of the slurry because its density is less than the density of the water solution of the separating agent, which is equivalent to arranging the fibers and the graphite particles in layers. Then, the top layer of the slurry is separated, and the number of fibers in the top layer of the slurry is obtained. In this way, it can be known how many fibers are contained in a certain mass of graphite powder, which facilitates good quality control of the graphite powder. In addition, the water solution of the separating agent can be used to separate the graphite powder and the fibers, and the use of this detection method can reduce the amount of pure water used and reduce the detection cost of the detection method.

[0008] In one of the embodiments, the aqueous solution of the separating agent is a colorless transparent solution. Since the aqueous solution of the separating agent is a colorless transparent solution, it is convenient to observe whether the fibers and the graphite particles in the slurry are arranged in layers so as to separate the top layer of the slurry as needed, thereby improving the operation convenience of the detection method of the present application.

[0009] In one of the embodiments, the aqueous solution of the separating agent includes an aqueous solution of zinc chloride. On the one hand, the aqueous solution of zinc chloride is a colorless transparent aqueous solution, which is convenient to separate the top layer of the slurry as needed, thereby improving the operation convenience of the detection method of the present application. On the other hand, the aqueous solution of zinc chloride satisfying the density condition that the density of the aqueous solution of zinc chloride is less than the density of the graphite particles and greater than the density of the fibers can be easily prepared by dissolving a certain mass of zinc chloride in a certain volume of pure water, thereby improving the convenience of detection. In addition, the aqueous solution of zinc chloride is non-toxic and non-corrosive, which can improve the safety of the detection method and reduce the pollution degree of subsequent water treatment of the detection method.

[0010] In one of the embodiments, the density of the aqueous solution of zinc chloride is 1.5 grams per cubic centimeter (g / cm 3 ) to 1.8 grams per cubic centimeter (g / cm 3 ). The density of the prepared aqueous solution of zinc chloride is selected within a suitable range, such as 1.5 grams per cubic centimeter (g / cm 3 ) to 1.8 grams per cubic centimeter (g / cm 3 ), which can make the density of the prepared aqueous solution of zinc chloride greatly different from the density of the graphite particles, thereby facilitating the use of the aqueous solution of zinc chloride to make the graphite particles deposit in the bottom layer of the slurry under the action of gravity, and further facilitating the use of the aqueous solution of zinc chloride to arrange the fibers and the graphite particles in layers, so as to subsequently separate the top layer of the slurry and obtain the number of fibers in the top layer of the slurry, thereby improving the reliability of the detection method of the present application.

[0011] In one of the embodiments, the preset mass is a and the preset volume is V, wherein the preset mass and the preset volume satisfy the following condition: V / a≥1.5 milliliters per gram (ml / g). In order to better separate the fibers and the graphite particles, it is necessary to mix the graphite powder of the preset mass with a sufficient volume of the aqueous solution of the separating agent, so that the fibers and the graphite particles can be spaced apart by a distance in the slurry, thereby facilitating the separation of the fibers located in the top layer of the slurry to obtain the number of fibers, and therefore, it is necessary to make the preset mass and the preset volume satisfy the following condition: V / a≥1.5 milliliters per gram (ml / g).

[0012] In one of the embodiments, the preset mass and the preset volume satisfy the following condition: 1.5 milliliters per gram (ml / g)≤V / a≤3 milliliters per gram (ml / g).

[0013] In one of the embodiments, the top layer of the slurry is separated, specifically including: the top layer of the slurry is separated by using the way of flow guide. It is convenient to obtain the number of fibers in the top layer of the slurry.

[0014] In one of the embodiments, before the top layer of the slurry is separated, the detection method further includes: adding a flocculating agent to the slurry. The flocculating agent can interact with the graphite particles in the slurry to form larger flocs, so that the graphite particles can be flocculated and precipitated. The flocculating agent can be used to better and faster stratify the fibers and graphite particles, which is convenient for subsequent better separation of the top layer of the slurry to obtain the number of fibers in the top layer of the slurry.

[0015] In one of the embodiments, the flocculating agent includes a water-soluble flocculating agent. The water-soluble flocculating agent can be well dissolved in water, so that the flocculating agent can better and faster contact the graphite particles in the slurry, which can better flocculate and precipitate the graphite particles, and further facilitate better stratification of the fibers and graphite particles, which is convenient for subsequent better separation of the top layer of the slurry to obtain the number of fibers in the top layer of the slurry.

[0016] In one of the embodiments, the mass of water in the water solution of the separating agent is b, and the mass of the added flocculating agent is greater than or equal to 0.002b, and the mass units of the graphite particles and the flocculating agent are grams. In order to better and faster contact the flocculating agent with the graphite particles in the slurry, enough flocculating agent can be added according to the mass of water in the water solution of the separating agent, for example, the mass of water in the water solution of the separating agent is b, and the mass of the added flocculating agent is greater than or equal to 0.002b.

[0017] In one of the embodiments, the mass of water in the water solution of the separating agent is b, and the mass of the added flocculating agent is 0.0025b-0.01b.

[0018] In one of the embodiments, before the top layer of the slurry is separated, the detection method further includes: treating the slurry with the added flocculating agent by using the way of centrifugal separation. The way of centrifugal separation can better and faster stratify the fibers and graphite particles, which is further conducive to better separation of the top layer of the slurry to obtain the number of fibers in the top layer of the slurry.

[0019] In one of the embodiments, before the top layer of the slurry is separated, the detection method further includes: mixing the graphite powder, the water solution of the separating agent and the flocculating agent by using the way of stirring. The graphite powder, the water solution of the separating agent and the flocculating agent can be fully dispersed, which is conducive to the interaction between the flocculating agent and the graphite particles to flocculate and precipitate the graphite particles, and further better stratify the fibers and graphite particles by using the water solution of the separating agent to obtain the number of fibers in the top layer of the slurry.

[0020] In one of the embodiments, the graphite powder, the water solution of the separating agent and the flocculating agent are mixed by stirring, specifically including: mixing the graphite powder, the water solution of the separating agent and the flocculating agent at a first preset stirring speed for a first preset time; mixing the graphite powder, the water solution of the separating agent and the flocculating agent at a second preset stirring speed for a second preset time; wherein the first preset stirring speed is less than the second preset stirring speed. The graphite powder, the water solution of the separating agent and the flocculating agent are first mixed at a smaller stirring speed for a first preset time, so as to reduce the probability of the graphite powder flying; and then the graphite powder, the water solution of the separating agent and the flocculating agent are mixed at a larger stirring speed for a second preset time, which is conducive to the contact between the flocculating agent and the graphite particles, and is conducive to the interaction between the flocculating agent and the graphite particles so that the graphite particles can be flocculated and precipitated, and then the water solution of the separating agent can be better used to arrange the fibers and the graphite particles in layers, so as to better obtain the number of fibers in the top layer of the slurry.

[0021] In one of the embodiments, before the top layer of the slurry is separated, the detection method further includes: adding a surfactant into the slurry. Since one end of the surfactant is a hydrophilic group and the other end is a hydrophobic group, the graphite particles in the graphite powder can be adsorbed by the hydrophobic group of the surfactant, and then the graphite particles can be more uniformly dispersed in the water solution of the separating agent by the hydrophilic group of the surfactant, so as to better separate the fibers mixed into the graphite particles, improve the separation effect of the fibers and the graphite particles, and then more accurately detect the number of fibers by using the detection method.

[0022] In one of the embodiments, the preset mass is a, and the mass of the added surfactant is c; wherein 0.02a≤c≤0.07a, and the mass units of the graphite particles and the surfactant are grams. According to the preset mass, the mass of the added surfactant is set in a suitable range, which is conducive to better dispersing the graphite particles in the water solution of the separating agent by the hydrophilic group of the surfactant, can improve the separation effect of the fibers and the graphite particles, and then more accurately detect the number of fibers by using the detection method.

[0023] In one of the embodiments, 0.03a≤c≤0.06a.

[0024] In one of the embodiments, the number of fibers in the top layer of the slurry is obtained, specifically including: flowing the separated top layer of the slurry through the visible cell at a preset speed; obtaining a plurality of detection images of the fibers flowing through the visible cell, and determining the number of fibers in the top layer of the slurry according to the plurality of detection images. The labor cost of manual counting can be reduced, and the number of fibers in the graphite powder can be more accurately and efficiently detected by using the detection method.

[0025] According to a first aspect of the present application, a detection device is provided, which is applied to the detection method of any of the above embodiments. The detection device comprises a mixing container, a separation mechanism and an acquisition mechanism. The mixing container has a mixing cavity for mixing graphite powder and an aqueous solution of a separating agent. The separation mechanism is arranged on the mixing container and is used to separate the top layer of the slurry from the mixing cavity. The acquisition mechanism is arranged on one side of the mixing container and is used to acquire the number of fibers in the top layer of the slurry. The detection device can be applied to the detection method described above, which can reduce the amount of pure water used and reduce the detection cost.

[0026] In one embodiment, the top of the side wall of the mixing container is provided with a separation outlet communicating with the mixing cavity. The separation mechanism comprises a flow guide for guiding the top layer of the slurry to flow out of the separation outlet. After the graphite powder and the aqueous solution of the separating agent are mixed to obtain the slurry, and the fibers are in the top layer of the slurry and the graphite particles are in the bottom layer of the slurry, the flow guide can guide the top layer of the slurry to flow out of the separation outlet, thereby facilitating the acquisition of the number of fibers in the top layer of the slurry.

[0027] In one embodiment, the separation mechanism further comprises a gas supply member connected to the flow guide. The gas supply member has a gas supply port, and the flow guide has a gas blowing port arranged towards the separation outlet, and the gas blowing port respectively communicates with the separation outlet and the gas supply port. The gas supply port and the gas blowing port of the gas supply member can be used to introduce a gas that does not react with the substances in the mixing cavity, such as air or inert gas, into the mixing cavity. The gas blowing port is 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, thereby driving the top layer of the slurry to flow towards the separation outlet, and then the top layer of the slurry can be separated from the mixing cavity, so as to subsequently acquire the number of fibers in the top layer of the slurry.

[0028] In one embodiment, the detection device further comprises a viewing cell located outside the mixing container and on one side of the acquisition mechanism. The viewing cell has a viewing cavity communicating with the separation outlet, and the viewing cell is located below the separation outlet in a direction parallel to the top of the mixing container and pointing to the bottom of the mixing container. The viewing cell comprises a viewing portion for observing the fibers. After the top layer of the slurry is separated from the mixing cavity, it slowly flows into the viewing cell under the action of gravity. The fibers flowing into the viewing cell can be observed through the viewing portion, and then the number of fibers in the top layer of the slurry can be acquired by the acquisition mechanism.

[0029] In one of the embodiments, 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 visual 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, and before the top layer of the slurry flows into the visual pool, the top layer of the slurry can flow through the flow guide pipe, and the fibers in the top layer of the slurry can be fully dispersed in the top layer of the slurry by the ultrasonic disperser arranged on the flow guide pipe, so as to reduce the reunion of the fibers, and thus to facilitate better acquisition of the number of fibers in the top layer of the slurry.

[0030] In one of the embodiments, the acquisition mechanism comprises a high-speed camera facing the visual part. The high-speed camera can be used to well acquire a plurality of detection images of the fibers flowing into the visual pool, and facilitate determination of the number of fibers in the top layer of the slurry according to the plurality of detection images.

[0031] In one of the embodiments, the detection device further comprises a water inlet mechanism and a water outlet mechanism, the water inlet mechanism has a water inlet communicated with the mixing cavity, the water outlet mechanism has a water return outlet, and the visual cavity is communicated between the separation outlet and the water return outlet. Pure water can be provided into the mixing cavity of the mixing container through the water inlet mechanism, the separation agent and the pure water form a pre-set volume of the separation agent aqueous solution in the mixing cavity, and a pre-set mass of graphite powder is added in the mixing cavity to form the slurry, the graphite particles and the fibers can be arranged in layers in the slurry, the top layer of the slurry can be separated from the mixing cavity by the separation mechanism, and the top layer of the slurry can flow through the visual cavity of the visual pool, in this process, the acquisition mechanism can acquire the number of fibers in the top layer of the slurry through the visual part, after the detection of the number of fibers is completed, the top layer of the slurry after detection can be collected and processed through the water outlet mechanism. In this way, the separated top layer of the slurry can flow through the visual pool at a pre-set speed, and the acquisition mechanism can acquire the number of fibers in the top layer of the slurry through the visual part.

[0032] The above description is only a summary of the technical solutions of the present application, in order to more clearly understand the technical means of the present application, the specific embodiments of the present application can be implemented according to the content of the description, and in order to make the above and other purposes, features and advantages of the present application more obvious and easy to understand, the following will specifically describe the embodiments of the present application. BRIEF DESCRIPTION OF DRAWINGS

[0033] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following will briefly introduce the drawings needed to be used in the embodiments of the present application. Obviously, the drawings described below are only some embodiments of the present application, and other drawings can also be obtained by those skilled in the art without creating any creative labor. In the drawings:

[0034] Fig. 1 shows a flow diagram of a detection method according to an embodiment of the present application.

[0035] FIG2 shows a schematic structural diagram of a detection device according to an embodiment of the present application.

[0036] FIG3 shows a schematic flow chart of a detection method according to another embodiment of the present application.

[0037] FIG4 shows a schematic structural diagram of a detection device according to another embodiment of the present application.

[0038] Figure numerals: 10, detection device; 110, mixing container; 1101, mixing chamber; 1102, separation outlet; 120, separation mechanism; 121, guide piece; 1211, air outlet; 122, air supply piece; 130, acquisition mechanism; 140, visual pool; 141, visual part; 1401, visual chamber; 151, guide pipe; 152, valve; 160, ultrasonic disperser; 171, water inlet mechanism; 1711, water supply port; 172, drainage mechanism; 1721, return water port; 173, connecting pipe; 174, sewage pipe; 180, stirring mechanism; 181, motor; 182, gear assembly; 183, stirring paddle; 20, graphite particles; 30, fiber; 40, slurry; 41, top layer; 42, bottom layer. DETAILED DESCRIPTION

[0039] To make the above-mentioned objects, features, and advantages of the present application more clearly understood, the specific embodiments of the present application are described in detail below with reference to the accompanying drawings. The following description sets forth many specific details to facilitate a full understanding of the present application. However, the present application can be implemented in many other ways than those described herein, and those skilled in the art can make similar improvements without violating the scope of the present application. Therefore, the present application is not limited to the specific embodiments disclosed below.

[0040] In the description of the present application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.

[0041] In addition, the terms "first", "second", etc. are used only for descriptive purposes and do not connote or imply relative importance or an ordering between or among the indicated features. Thus, a feature defined with "first", "second", etc. can include at least one of the features implicitly or explicitly. In the description of the present application, the meaning of "a plurality" is at least two, for example, two, three, etc., unless otherwise explicitly specified and limited.

[0042] In the present application, unless specifically and particularly defined otherwise, the terms "mounting", "connecting", "connecting", "fixing" and the like should be interpreted broadly, for example, it can be fixed connection, or detachable connection, or integrated; it can be mechanical connection, or electrical connection; it can be direct connection, or indirect connection through intermediate medium; it can be the internal communication of two elements or the interaction relationship between two elements, unless otherwise specifically defined. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0043] In the present application, unless specifically and particularly defined otherwise, the first feature is "on" or "under" the second feature, which can be direct contact between the first and second features, or indirect contact between the first and second features through intermediate medium. Moreover, the first feature "above", "over" and "on" the second feature can be directly above or obliquely above the first feature, or only indicate that the horizontal height of the first feature is higher than that of the second feature. The first feature "below", "under" and "under" the second feature can be directly below or obliquely below the first feature, or only indicate that the horizontal height of the first feature is less than that of the second feature.

[0044] It should be noted that when an element is referred to as "fixed to" or "disposed on" another element, it can be directly on the other element or there can be a middle element. When an element is referred to as "connected to" another element, it can be directly connected to the other element or there can be a middle element. The terms "vertical", "horizontal", "up", "down", "left", "right" and similar expressions used herein are for illustrative purposes only and are not the only implementation.

[0045] It is found through research that the fibers in the graphite powder can cause unevenness of the surface of the coated negative electrode sheet. Therefore, it is necessary to provide a detection method capable of detecting impurities such as fibers in the graphite powder, so as to provide corresponding guidance for the quality control of the graphite powder.

[0046] In the related art, a small amount of graphite (such as 3g) is added to a large amount of pure water (such as 25L) to achieve effective dispersion of graphite particles and clear visibility of the fiber morphology in the graphite, and then the fiber in the graphite can be qualitatively analyzed. However, the detection method of the graphite particles in the related art needs to consume a large amount of pure water.

[0047] To solve the problem that the detection method of the graphite particles in the related art needs to consume a large amount of pure water, the present application designs a detection method and a detection device, which can use a water solution of a separating agent to make the fiber and the graphite particles in the graphite powder layer, facilitate the separation of the fiber in the upper layer, and then obtain the number of the fiber. This detection method can reduce the amount of pure water used and reduce the detection cost.

[0048] The detection method and / or the detection device disclosed in the embodiments of the present application can be used in the production of batteries, but are not limited thereto.

[0049] FIG. 1 shows a flowchart of the detection method according to an embodiment of the present application. FIG. 2 shows a structural schematic diagram of a detection device 10 according to an embodiment of the present application.

[0050] Referring to FIGS. 1 and 2, the detection method provided by an embodiment of the present application is used to detect the fiber 30 in the graphite powder. The detection method includes the following steps:

[0051] S10, mixing a predetermined mass of graphite powder and a predetermined volume of a water solution of a separating agent to form a slurry 40, so that the fiber 30 and the graphite particles 20 in the graphite powder are layered, and the fiber 30 is located in the top layer 41 of the slurry 40, and the graphite particles 20 are located in the bottom layer 42 of the slurry 40; wherein the density of the water solution of the separating agent is less than the density of the graphite particles 20 and greater than the density of the fiber 30.

[0052] The water solution of the separating agent refers to a water solution whose density is greater than that of the fiber 30 and less than that of the graphite particles 20, and which can make the fiber 30 and the graphite particles 20 layered. It should be noted that the water solution of the separating agent does not react with the fiber 30 and the graphite particles 20.

[0053] The water solution of the separating agent includes pure water and a separating agent that is easily soluble in water. A certain mass of the separating agent is dissolved in a certain volume of pure water to prepare the water solution of the separating agent, and the density of the water solution of the separating agent is less than the density of the graphite particles 20 and greater than the density of the fiber 30.

[0054] The separation agent can be selected according to the density condition that the density of the water solution of the separation agent is less than the density of the graphite particles 20 and greater than the density of the fibers 30. The separation agent can be a substance that can meet the above density condition and is easily soluble in water, such as an inorganic compound that can meet the above density condition and is easily soluble in water. In some embodiments, the separation agent can be a metal halide that can meet the above density condition and is easily soluble in water.

[0055] The appearance of the water solution of the separation agent can also be used as a condition for selecting the separation agent. For example, the appearance condition includes that the water solution of the separation agent is a transparent water solution, and in some embodiments, the appearance condition includes that the water solution of the separation agent can be a colorless transparent solution. In this way, the top layer 41 of the slurry 40 can be easily separated out as needed.

[0056] The top layer 41 of the slurry 40 refers to a solution layer in the slurry 40 located on the top side of the bottom layer 42 and in which the fibers 30 are arranged. The bottom layer 42 of the slurry 40 refers to a solution layer in the slurry 40 located on the bottom side of the top layer 41 and in which the graphite particles 20 are arranged.

[0057] In some embodiments, the graphite powder of a predetermined mass and the water solution of the separation agent of a predetermined volume can be mixed uniformly by stirring, and then the fibers 30 and the graphite particles 20 in the graphite powder can be arranged in layers by standing.

[0058] S20, the top layer 41 of the slurry 40 is separated out.

[0059] The top layer 41 of the slurry 40 can be separated out by suction, or by drainage, or by overflow. No specific limitation is made herein.

[0060] S30, the number of fibers 30 in the top layer 41 of the slurry 40 is obtained.

[0061] The separated top layer 41 of the slurry 40 can pass through a filter element to intercept the fibers 30, and then the number of the fibers 30 can be obtained. The number of the fibers 30 in the top layer 41 of the slurry 40 can also be obtained by other methods.

[0062] The number of the fibers 30 in the top layer 41 of the slurry 40 can be obtained directly by naked eye observation, or by a camera or a microscope. For example, the microscope can be a Keyence digital microscope, a Leica microscope system, or a JOMESA.

[0063] Since the density of the water solution of the separating agent is less than the density of the graphite particles 20 and greater than the density of the fibers 30, after the graphite powder of a preset mass and the water solution of the separating agent of a preset volume are mixed to form the slurry 40, the graphite powder can deposit at the bottom layer 42 of the slurry 40 under the action of gravity because the density of the graphite powder is greater than the density of the water solution of the separating agent, and the fibers 30 can float on the top layer 41 of the slurry 40 because the density of the fibers 30 is less than the density of the water solution of the separating agent, which is equivalent to layering the fibers 30 and the graphite particles 20, and 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, so that the number of the fibers 30 in the graphite powder of a certain mass can be known, and the quality of the graphite powder can be well controlled. In addition, the water solution of the separating agent can well separate the graphite powder and the fibers 30, and the detection method does not need to consume a large amount of pure water, and the use amount of the pure water can be reduced, and the detection cost of the detection method can be reduced.

[0064] In some embodiments, the water solution of the separating agent is a colorless transparent solution.

[0065] That is, the appearance condition includes that the water solution of the separating agent is a colorless transparent solution.

[0066] For example, the water solution of the separating agent can be a zinc chloride solution or a potassium chloride solution, and of course, other water solutions that meet the above appearance condition and density condition can also be selected.

[0067] Since the water 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 can be observed, so that the top layer 41 of the slurry 40 can be separated according to needs, and the operation convenience of the detection method of the present application can be improved.

[0068] In some embodiments, the water solution of the separating agent includes a zinc chloride solution.

[0069] On the one hand, the zinc chloride solution is a colorless transparent solution, which facilitates the separation of the top layer 41 of the slurry 40 according to needs, and improves the operation convenience of the detection method of the present application. On the other hand, the zinc chloride solution that meets the density condition that the density of the zinc chloride solution is less than the density of the graphite particles 20 and greater than the density of the fibers 30 can be easily configured by dissolving a certain mass of zinc chloride in a certain volume of pure water, and the detection convenience can be improved. In addition, the zinc chloride solution is non-toxic and non-corrosive, which can improve the safety of the detection method and reduce the pollution degree of subsequent water treatment of the detection method.

[0070] In some embodiments, the density of the zinc chloride solution is 1.5 grams per cubic centimeter (g / cm 3 -1.8 grams per cubic centimeter (g / cm 3).

[0071] For example, the density of the zinc chloride aqueous solution is 1.5 grams per cubic centimeter (g / cm 3 ), 1.6 grams per cubic centimeter (g / cm 3 ), 1.7 grams per cubic centimeter (g / cm 3 ), or 1.8 grams per cubic centimeter (g / cm 3 ).

[0072] Generally, the density of the fiber 30 ranges from 0.91 grams per cubic centimeter (g / cm 3 ) to 1.54 grams per cubic centimeter (g / cm 3 ), and the density of the graphite particles 20 ranges from 2.09 grams per cubic centimeter (g / cm 3 ) to 2.23 grams per cubic centimeter (g / cm 3 ). Based on this, the density of the prepared zinc chloride aqueous solution is selected in a suitable range, such as 1.5 grams per cubic centimeter (g / cm 3 ) to 1.8 grams per cubic centimeter (g / cm 3 ), so that the density of the prepared zinc chloride aqueous solution is greatly different from the density of the graphite particles 20, which is beneficial to better use the zinc chloride aqueous solution to make the graphite particles 20 deposit at the bottom layer 42 of the slurry 40 under the action of gravity, and thus the zinc chloride aqueous solution can be better used to make the fiber 30 and the graphite particles 20 be layered, so as to subsequently separate the top layer 41 of the slurry 40 and obtain the number of the fiber 30 in the top layer 41 of the slurry 40, and thus the reliability of the detection method of the present application can be improved.

[0073] In some embodiments, the preset mass is a and the preset volume is V, wherein the preset mass and the preset volume satisfy the following condition: V / a≥1.5 milliliters per gram (ml / g).

[0074] For example, V / a is 1.5 milliliters per gram (ml / g), 2.5 milliliters per gram (ml / g), or 3.5 milliliters per gram (ml / g), etc.

[0075] It can be understood that the mass unit of the graphite particles 20 is grams, and the volume unit of the preset volume is milliliters.

[0076] wherein a is 50 grams (g) to 100 grams (g), and V can be 150 milliliters (ml) to 250 milliliters (ml). For example, a is 50 grams (g), 75 grams (g), or 100 grams (g), and V can be 150 milliliters (ml), 200 milliliters (ml), or 250 milliliters (ml).

[0077] In order to better separate the fibers 30 and the graphite particles 20, the preset mass of the graphite powder is mixed with a sufficient volume of the aqueous solution of the separating agent, so that the fibers 30 and the graphite particles 20 can be spaced apart in the slurry 40, thereby facilitating the separation of the fibers 30 in the top layer 41 of the slurry 40 to obtain the number of the fibers 30. Therefore, the preset mass and the preset volume need to satisfy the following condition: V / a≥1.5 ml / g.

[0078] In some embodiments, the preset mass and the preset volume satisfy the following condition: 1.5 ml / g≤V / a≤3 ml / g.

[0079] For example, V / a is 1.5 ml / g, 2.5 ml / g, or 3 ml / g, etc. In some embodiments, a is 50 g, 60 g, 70 g, 80 g, 90 g, or 100 g, and V can be 150 ml, 160 ml, 170 ml, 180 ml, 190 ml, 200 ml, 210 ml, 220 ml, 230 ml, 240 ml, or 250 ml.

[0080] In this way, the fibers 30 and the graphite particles 20 can be well spaced apart in the slurry 40, thereby facilitating the separation of the fibers 30 in the top layer 41 of the slurry 40 to obtain the number of the fibers 30, and the volume of the aqueous solution of the separating agent can be reduced in the case that the mass of the graphite particles 20 is inconvenient, thereby reducing the detection cost of the detection method.

[0081] In some embodiments, the step S20 of separating the top layer 41 of the slurry 40 specifically includes:

[0082] S21, the top layer 41 of the slurry 40 is separated by using a drainage method.

[0083] For example, the top layer 41 of the slurry 40 is separated by using a drainage device, so as to obtain the number of the fibers 30 in the top layer 41 of the slurry 40.

[0084] 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:

[0085] S11, a flocculating agent is added to the slurry 40.

[0086] The flocculant can be selected from inorganic flocculants, such as polyaluminum chloride, and can also be selected from organic flocculants, such as polyacrylamide. Water-soluble flocculants can be selected, and water-insoluble flocculants can also be selected. In some embodiments, the flocculant can be selected according to actual needs.

[0087] The flocculant can interact with the graphite particles 20 in the slurry 40 to form larger flocs, so that the graphite particles 20 can be flocculated and precipitated. The flocculant can be used to better and faster stratify the fibers 30 and the graphite particles 20, which facilitates better separation of the top layer 41 of the slurry 40 in the future, so as to obtain the number of fibers 30 in the top layer 41 of the slurry 40.

[0088] In some embodiments, the flocculant includes a water-soluble flocculant.

[0089] The water-soluble flocculant can be selected to better dissolve in water, so that the flocculant can better and faster contact the graphite particles 20 in the slurry 40, which can better flocculate and precipitate the graphite particles 20, and thus facilitates better stratification of the fibers 30 and the graphite particles 20, which facilitates better separation of the top layer 41 of the slurry 40 in the future, so as to obtain the number of fibers 30 in the top layer 41 of the slurry 40.

[0090] In some embodiments, the mass of water in the water solution of the separating agent is b, and the mass of the added flocculant is greater than or equal to 0.002b, and the mass units of the graphite particles 20 and the flocculant are grams.

[0091] For example, the mass of water in the water solution of the separating agent is b, and the mass of the added flocculant is 0.003b, 0.0025b, 0.00375b, or 0.004b. For example, the mass of water in the water solution of the separating agent is 800 grams (g), and the mass of the flocculant is 3 grams (g).

[0092] In order to better make the flocculant better and faster contact the graphite particles 20 in the slurry 40, sufficient flocculant can be added according to the mass of water in the water solution of the separating agent, for example, the mass of water in the water solution of the separating agent is b, and the mass of the added flocculant is greater than or equal to 0.002b, and the mass units of the graphite particles 20 and the flocculant are grams.

[0093] In some embodiments, the mass of water in the water solution of the separating agent is b, and the mass of the added flocculant is 0.0025b-0.01b.

[0094] In some embodiments, the mass of the added flocculating agent is 0.0025b-0.004b. For example, the mass of the added flocculating agent is 0.003b-0.0038b. Illustratively, the mass of water in the aqueous solution of the separating agent is b, and the mass of the added flocculating agent is 0.003b, 0.0033b, 0.0036b, or 0.0038b. The mass of water in the aqueous solution of the separating agent is 900 grams (g), and the mass of the flocculating agent is 3 grams (g).

[0095] In this way, on the one hand, the flocculating agent can be made to contact the graphite particles 20 in the slurry 40 more and faster, and the graphite particles 20 can be better flocculated and precipitated, which is conducive to better layering of the fibers 30 and the graphite particles 20, and is also conducive to 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. On the other hand, the cost of the flocculating agent can be reasonably controlled.

[0096] 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:

[0097] S12, treating the slurry 40 to which the flocculating agent is added by using centrifugal separation.

[0098] The fibers 30 and the graphite particles 20 can be better layering by using centrifugal separation, which is conducive to 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.

[0099] 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:

[0100] S13, mixing the graphite powder, the aqueous solution of the separating agent, and the flocculating agent by using stirring.

[0101] In some embodiments, the step S13 is located before the step S12.

[0102] The graphite powder, the aqueous solution of the separating agent, and the flocculating agent can be fully dispersed, which is conducive to the flocculating agent interacting with the graphite particles 20 to flocculate and precipitate the graphite particles 20, and then the aqueous solution of the separating agent can be better used to layer the fibers 30 and the graphite particles 20 (for example, the fibers 30 and the graphite particles 20 can be better layering by using centrifugal separation), so as to subsequently obtain the number of fibers 30 in the top layer 41 of the slurry 40.

[0103] In some embodiments, the step S13 of mixing the graphite powder, the aqueous solution of the separating agent, and the flocculating agent by using stirring specifically includes:

[0104] S131, mixing the graphite powder, the water solution of the separating agent, and the flocculating agent at a first preset stirring speed for a first preset time.

[0105] For example, the first preset time can be 1-3 minutes, such as 1, 2, or 3 minutes.

[0106] S132, mixing the graphite powder, the water solution of the separating agent, and the flocculating agent at a second preset stirring speed for a second preset time.

[0107] For example, the second preset time can be 9-12 minutes, such as 9, 10, 11, or 12 minutes.

[0108] The first preset stirring speed is less than the second preset stirring speed.

[0109] In some embodiments, the first preset stirring speed is less than or equal to 200 revolutions per minute (rpm), the second preset stirring speed is greater than 200 rpm and less than or equal to 500 rpm.

[0110] The first preset stirring speed can be 100 rpm or 200 rpm, and the stirring speed can be slowly increased to the first preset stirring speed within the first preset time. For example, the first preset stirring speed is 200 rpm, and the stirring speed can be increased by 50 rpm every 1 minute until the first preset stirring speed is reached.

[0111] The second preset stirring speed can be 400 rpm or 500 rpm, and the stirring speed can be slowly increased to the second preset stirring speed within the second preset time. For example, the second preset stirring speed is 500 rpm, and the stirring speed can be increased by 50 rpm every 1 minute until the second preset stirring speed is reached from the first preset stirring.

[0112] First, the graphite powder, the water solution of the separating agent, and the flocculating agent are mixed at a smaller stirring speed for a first preset time, which reduces the probability of the graphite powder flying; then, the graphite powder, the water solution of the separating agent, and the flocculating agent are mixed at a larger stirring speed for a second preset time, which is conducive to the flocculating agent fully contacting the graphite particles 20 and the flocculating agent interacting with the graphite particles 20 to flocculate and precipitate the graphite particles 20, and then the separating agent water solution can be better used to layer the fibers 30 and the graphite particles 20, so as to better obtain the number of fibers 30 in the top layer 41 of the slurry 40.

[0113] 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 comprises:

[0114] S14, adding a surfactant to the slurry 40.

[0115] In some embodiments, the surfactant can be selected from water-soluble surfactants or water-soluble surfactants, such as potassium lauryl ether phosphate, polysorbate, or X-3204 dispersant, etc.

[0116] Since 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 used to adsorb graphite particles 20 in the graphite powder, and the hydrophilic group of the surfactant can be used to disperse the graphite particles 20 more uniformly in the water solution of the separating agent, which is conducive to better separating the fibers 30 mixed between the graphite particles 20, improving the separation effect of the fibers 30 and the graphite particles 20, and thus facilitating more accurate detection of the number of fibers 30 using the detection method.

[0117] In some embodiments, step S14 can also be located before step S13, and step S13 is located before step S12, so that step S13 of mixing the graphite powder, the water solution of the separating agent, and the flocculant by stirring specifically includes: mixing the graphite powder, the water solution of the separating agent, the flocculant, and the surfactant by stirring. Step S12 of processing the slurry 40 added with the flocculant by centrifugal separation specifically includes: processing the slurry 40 added with the flocculant and the surfactant by centrifugal separation.

[0118] The graphite powder, the water solution of the separating agent, the flocculant, and the surfactant can be mixed by stirring to improve the dispersion effect of the surfactant, and thus the separation effect of the fibers 30 and the graphite particles 20 can be improved, and thus more accurate detection of the number of fibers 30 using the detection method can be facilitated.

[0119] In some embodiments, the preset mass is a, and the mass of the added surfactant is c, where 0.02a≤c≤0.07a, and the mass units of the graphite particles 20 and the surfactant are both grams.

[0120] For example, c is 0.02a, 0.03a, 0.04a, 0.05a, 0.06a, or 0.07a, and by way of example, the preset mass is 100g, and the mass of the added surfactant is 2g, 3g, 4g, 5g, 6g, or 7g.

[0121] According to the preset mass, the mass of the added surfactant is set in an appropriate range, which is conducive to better dispersing the graphite particles 20 uniformly in the water solution of the separating agent using the hydrophilic group of the surfactant, improving the separation effect of the fibers 30 and the graphite particles 20, and thus facilitating more accurate detection of the number of fibers 30 using the detection method.

[0122] In some embodiments, 0.03a≤c≤0.06a.

[0123] For example, c is 0.03a, 0.04a, 0.05a or 0.06a, and the preset mass is 100 grams (g), and the mass of the added surfactant is 3 grams (g), 4 grams (g), 5 grams (g) or 6 grams (g).

[0124] In this way, the graphite particles 20 can be uniformly dispersed in the aqueous solution of the separating agent by using a suitable amount of surfactant, the separation effect of the fibers 30 and the graphite particles 20 is improved, and the number of fibers 30 can be more accurately detected by using the detection method.

[0125] In some embodiments, the step S30 of obtaining the number of fibers 30 in the top layer 41 of the slurry 40 specifically comprises:

[0126] S31, the top layer 41 of the separated slurry 40 flows through the visible cell 140 at a preset speed.

[0127] The top layer 41 of the slurry 40 can flow through the visible cell 140 under the action of gravity, and at this time, the preset speed is gt (g is the acceleration of gravity, and t is the falling time of the top layer 41 of the slurry 40), or the top layer 41 of the slurry 40 can flow through the visible cell 140 at a preset speed by using a suction pump, which is not specifically limited herein.

[0128] S32, a plurality of detection images of the fibers 30 flowing through the visible cell 140 are obtained, and the number of fibers 30 in the top layer 41 of the slurry 40 is determined according to the plurality of detection images.

[0129] A plurality of detection images of the fibers 30 flowing through the visible cell 140 can be obtained, and the number of fibers 30 in the top layer 41 of the slurry 40 can be determined according to the plurality of detection images. In some embodiments, the plurality of detection images can be processed by using an image recognition analysis system, and the number of fibers 30 in the top layer 41 of the slurry 40 can be determined. In this way, the labor cost of manual counting can be reduced, and the number of fibers 30 in the graphite powder can be more accurately and efficiently detected by using the detection method.

[0130] Referring to FIGS. 2 and 4, an embodiment of the present application provides a detection device 10, which is applied to the detection method of any one of the above-mentioned embodiments. The detection device 10 comprises a mixing container 110, a separating mechanism 120 and an obtaining mechanism 130.

[0131] The mixing container 110 has a mixing cavity 1101 for mixing the graphite powder and the water solution of the separating agent. The separating mechanism 120 is arranged on the mixing container 110 and is used to separate the top layer 41 of the slurry 40 from the mixing cavity 1101. The obtaining mechanism 130 is arranged on one side of the mixing container 110 and is used to obtain the number of fibers 30 in the top layer 41 of the slurry 40.

[0132] The mixing container 110 can be a tank body, such as a centrifugal tank, a stirring tank, or a centrifugal stirring tank.

[0133] The separating mechanism 120 can include a suction pump connected to the mixing container 110. The suction pump can be used to separate the top layer 41 of the slurry 40 from the mixing cavity 1101 by suction. The separating mechanism 120 can also include a flow guide 121, which can be used to separate the top layer 41 of the slurry 40 from the mixing cavity 1101 by flow guidance. No specific limitation is made herein.

[0134] The obtaining mechanism 130 can be a microscope or a camera, and of course can also be other mechanisms capable of obtaining the number of fibers 30 in the top layer 41 of the slurry 40.

[0135] When the detection device 10 is used, the graphite powder and the water solution of the separating agent 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 allowed to stand and stratify or stratify by centrifugation, so that the fibers 30 and the graphite particles 20 are stratified. Then, the top layer 41 of the slurry 40 is separated by the separating mechanism 120, and the number of fibers 30 in the top layer 41 of the slurry 40 is obtained by the obtaining mechanism 130. The number of fibers 30 in a certain mass of graphite powder can be obtained, which facilitates good quality control of the graphite powder. In addition, the water solution of the separating agent can be used to separate the graphite powder and the fibers 30 well. This method does not need to consume a large amount of pure water, and can also reduce the use amount of pure water, thereby reducing the detection cost of the detection method.

[0136] In some embodiments, the top of the side wall of the mixing container 110 is provided with a separation outlet 1102 communicating with the mixing cavity 1101. The separating mechanism 120 includes a flow guide 121 for guiding the top layer 41 of the slurry 40 to flow out of the separation outlet 1102.

[0137] The flow guide 121 refers to a component capable of guiding the top layer 41 of the slurry 40 to flow out of the separation outlet 1102. The flow guide can be in the form of air blowing, or can be in the form of an overflow structure for guiding the top layer 41 of the slurry 40 to flow out of the separation outlet 1102.

[0138] The graphite powder and the water solution of the separating agent are mixed to obtain the slurry 40, and after the fibers 30 are located in the top layer 41 of the slurry 40 and the graphite particles 20 are located in the bottom layer 42 of the slurry 40, the top layer 41 of the slurry 40 can be guided to flow out by the flow guide 121 towards the separating outlet 1102, thereby facilitating the obtaining of the number of the fibers 30 in the top layer 41 of the slurry 40.

[0139] In some embodiments, the separating mechanism 120 further comprises a gas supply member 122 connected with the flow guide 121, the gas supply member 122 has a gas supply port, and the flow guide 121 has a gas blowing port 1211 arranged towards the separating outlet 1102, the gas blowing port 1211 is respectively connected with the separating outlet 1102 and the gas supply port.

[0140] The gas blowing port 1211 is arranged towards the separating outlet 1102, and the gas blowing port 1211 can also be arranged obliquely towards the separating outlet 1102, for example, the axis direction of the gas blowing port 1211 is arranged at an angle with the axis direction of the separating outlet 1102 and the direction of gravity of the mixing container 110.

[0141] In some embodiments, the flow guide 121 is arranged opposite to and spaced apart from the separating outlet 1102 on the side wall of the mixing container 110.

[0142] The gas supply port of the gas supply member 122 and the gas blowing port 1211 can be used to introduce a gas that does not react with the substances in the mixing chamber 1101, such as air or inert gas, into the mixing chamber 1101, and the gas blowing port 1211 is arranged towards the separating outlet 1102, so that the gas blown into the mixing chamber 1101 from the gas blowing port 1211 can flow towards the separating outlet 1102, thereby driving the top layer 41 of the slurry 40 to flow towards the separating outlet 1102, and the top layer 41 of the slurry 40 can be separated from the mixing chamber 1101, so as to subsequently obtain the number of the fibers 30 in the top layer 41 of the slurry 40.

[0143] In some embodiments, the detection device 10 further comprises a visual cell 140 located outside the mixing container 110 and on one side of the obtaining mechanism 130, the visual cell 140 has a visual chamber 1401 connected with the separating outlet 1102, the visual cell 140 is located on the lower side of the separating outlet 1102 in a direction parallel to the top of the mixing container 110 pointing to the bottom, and the visual cell 140 comprises a visual part 141 for observing the fibers 30.

[0144] Since the visual cell 140 is located on the lower side of the separating outlet 1102, after the top layer 41 of the slurry 40 is separated from the mixing chamber 1101, it can slowly flow into the visual cell 140 under the action of gravity, and the fibers 30 flowing into the visual cell 140 can be observed through the visual part 141, thereby the number of the fibers 30 in the top layer 41 of the slurry 40 can be obtained by the obtaining mechanism 130.

[0145] In some embodiments, the detection device 10 further comprises a flow guide pipe 151, one end of the flow guide pipe 151 being in communication with the separation outlet 1102, and the other end of the flow guide pipe 151 being in communication with the visual cavity 1401, and an ultrasonic disperser 160 arranged on the flow guide pipe 151.

[0146] After the top layer 41 of the slurry 40 is separated from the mixing cavity 1101, and before the top layer 41 of the slurry 40 flows into the visual pool 140, the top layer 41 of the slurry 40 can flow through the flow guide pipe 151, and the fibers 30 in the top layer 41 of the slurry 40 can be dispersed in the top layer 41 of the slurry 40 by the ultrasonic disperser 160 arranged on the flow guide pipe 151, so as to reduce the agglomeration of the fibers 30, and thus facilitate better acquisition of the number of the fibers 30 in the top layer 41 of the slurry 40.

[0147] In some embodiments, a valve 152 is arranged at the separation outlet 1102 or on the flow guide pipe 151.

[0148] The valve 152 can be closed first, the graphite powder and the aqueous solution of the separation agent are mixed to obtain the slurry 40, and after the fibers 30 and the graphite particles 20 are arranged in layers, the valve 152 can be opened, so that the top layer 41 of the slurry 40 is separated from the separation outlet 1102, and the number of the fibers 30 in the top layer 41 of the slurry 40 is facilitated to be acquired subsequently.

[0149] In some embodiments, the acquisition mechanism 130 comprises a high-speed camera facing the visual part 141.

[0150] The high-speed camera can be used to well acquire a plurality of detection images of the fibers 30 flowing into the visual pool 140, and facilitate determination of the number of the fibers 30 in the top layer 41 of the slurry 40 according to the plurality of detection images.

[0151] In some embodiments, the acquisition mechanism 130 further comprises an image recognition analysis system electrically connected with the high-speed camera, and the image recognition analysis system is used to process the plurality of detection images and determine the number of the fibers 30 in the top layer 41 of the slurry 40.

[0152] In some embodiments, the detection device 10 further comprises a stirring mechanism 180, the stirring mechanism 180 comprising a motor 181, a gear assembly 182 connected with the motor 181, a stirring paddle 183 coaxially arranged with one gear of the gear assembly 182, and an end of the stirring paddle 183 away from the gear assembly 182 extending into the mixing cavity 1101.

[0153] The motor 181 can drive the gears of the gear assembly 182 to rotate, thereby driving the stirring paddle 183 to rotate, and the materials in the mixing cavity 1101 can be stirred, for example, the graphite powder, the aqueous solution of the separation agent, and the flocculating agent can be mixed by stirring.

[0154] In some embodiments, the detection device 10 further comprises a controller (not shown in the figure) electrically connected with 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.

[0155] In some embodiments, the detection device 10 further comprises a water inlet mechanism 171 having a water inlet port 1711 in communication with the mixing cavity 1101 and a water outlet mechanism 172 having a water outlet port 1721 in communication between the visual cavity 1401 and the separation outlet 1102 and the water outlet port 1721.

[0156] In some embodiments, the detection device 10 further comprises a communication pipe 173 in communication between the visual cavity 1401 and the water outlet port 1721.

[0157] In this way, the mixing cavity 1101 of the mixing container 110 can be provided with pure water through the water inlet mechanism 171, the separation agent and the pure water can form a separation agent aqueous solution of a preset volume in the mixing cavity 1101, and a graphite powder of a preset mass can be added to the mixing cavity 1101 to form the slurry 40, the graphite particles 20 and the fibers 30 can be arranged in layers in the slurry 40, the top layer 41 of the slurry 40 can be separated from the mixing cavity 1101 through the separation mechanism 120, and the top layer 41 of the slurry 40 can flow through the visual cavity 1401 of the visual cell 140, in the process, the acquisition mechanism 130 can acquire the number of fibers 30 in the top layer 41 of the slurry 40 through the visual part 141, after the number of fibers 30 is detected, the top layer 41 of the slurry 40 after detection can be collected and processed through the water outlet mechanism 172. In this way, the separated top layer 41 of the slurry 40 can flow through the visual cell 140 at a preset speed, facilitating the acquisition mechanism 130 to acquire the number of fibers 30 in the top layer 41 of the slurry 40 through the visual part 141, for example, a high-speed camera can be used to capture a plurality of detection images of a plurality of fibers 30 flowing through the visual cell 140, and an image recognition analysis system can be used to process the plurality of detection images and determine the number of fibers 30 in the top layer 41 of the slurry 40.

[0158] In other embodiments, the detection device 10 further comprises a sewage pipe 174, and the visual cavity 1401 is in communication with the sewage pipe 174 away from the separation outlet 1102.

[0159] In this way, the top layer 41 of the slurry 40 can also flow through the visual cavity 1401 of the visual cell 140, facilitating the use of a high-speed camera to capture a plurality of detection images of a plurality of fibers 30 flowing through the visual cell 140, and the use of an image recognition analysis system to process the plurality of detection images and determine the number of fibers 30 in the top layer 41 of the slurry 40.

[0160] Test Example One

[0161] To investigate the applicability of the detection method of the present application, graphite powder including fiber-free graphite and fiber 30 is taken as an example. In the case of the same mass of fiber-free graphite, the same type and the same number of fiber 30 are selected, and the detection of the aqueous solution of the separating agent with different densities is carried out under the condition that the density of the aqueous solution of the separating agent is different. In some embodiments, 800 milliliters (ml) of pure water is injected into the mixing container 110 (centrifugal stirring tank) by using the water inlet mechanism 171, and different masses of zinc chloride powder are added. After uniform stirring, the aqueous solution of the separating agent is obtained, different densities of the aqueous solution of the separating agent can be obtained, and 400 grams (g) of fiber-free graphite, 3 grams (g) of flocculating agent and 20 grams (g) of surfactant (the surfactant is selected as X-3204 dispersant) are added. Then, 30 fibers 30 (the fibers can be first type fibers, the first type fibers are ribbon fibers, white and circular column-shaped, the length of the first type fibers is 1000 micrometers, and the diameter of the first type fibers is 25 micrometers) are mixed and stirred. The stirring speed is slowly increased to 200 revolutions per minute (rpm) within 0-3 minutes, and then slowly increased to 500 revolutions per minute (rpm), and continues to stir for 12 minutes. After stirring is completed, the material in the mixing container 110 is subjected to centrifugal treatment, so that the fibers 30 and the graphite particles 20 are arranged in layers. Then, the top layer 41 of the slurry 40 is separated, and the number of fibers 30 in the top layer 41 of the slurry 40 is obtained. The detection results of different types of aqueous solutions are as shown in Table 1.

[0162] Table 1

[0163] The detection rate is the percentage of the number of detected fibers to the number of fibers actually contained in the graphite powder. The comparative substances are white sugar, sodium citrate, ammonium sulfate or ammonium acetate.

[0164] As described above, in the related art, a small amount of graphite (such as 3 grams) is added to a large amount of pure water (such as 25 liters) to achieve effective dispersion of the graphite particles 20 and clear visibility of the fiber morphology in the graphite. In the case where the mass of fiber-free graphite and the mass of pure water are the same as in the present application examples 1-4, the detection rate of the fiber in Comparative Example 6 is zero. Obviously, in Comparative Example 6, because the amount of pure water is small, the graphite particles 20 cannot be effectively dispersed, which affects the detection of the fiber 30. It is also verified that a large amount of pure water needs to be added to the graphite to achieve effective dispersion of the graphite particles 20. In Comparative Examples 1-6, the density of the aqueous solution is too small, less than 1.4 grams per cubic centimeter (g / cm 3), leading to the fibers being easily deposited at the bottom layer of the aqueous solution, and further leading to the difficulty in separating the fibers 30 from the graphite particles 20, and further leading to the low detection rate of the Comparative Examples 1-6; compared to the Comparative Examples 1-6, the use amount of pure water can be greatly reduced by using the detection method of the present application, and the detection rate is higher, especially when the density of the zinc chloride aqueous solution is 1.5 grams per cubic centimeter (g / cm 3 )-1.8 grams per cubic centimeter (g / cm 3 ), the detection rate can be greater than 80% or even greater than 90%, thus it can be seen that the accuracy of the detection method of the present application is high, and can be well applied to the graphite powder material in actual production, so as to well control the quality of the graphite powder material, and reduce the problem of uneven surface of the negative electrode sheet coated by using the graphite powder material.

[0165] Test Example Two

[0166] In order to investigate the applicability of the detection method of the present application to different types of fibers, in this test example, the graphite powder material including fiberless graphite and fibers is taken as an example for illustration, in the case of the same mass of fiberless graphite, different types of fibers are selected, and for each type of fiber, three groups of detection of different fiber concentrations are carried out. In some embodiments, the water inlet mechanism 171 is used to inject 800 milliliters (ml) of pure water into the mixing container 110 (centrifugal stirring tank), and then 1 kilogram (kg) of zinc chloride powder is added, and after being stirred uniformly, a separation agent aqueous solution is obtained, and then 500 grams (g) of fiberless graphite, 3 grams (g) of flocculating agent and 20 grams (g) of surfactant (the surfactant is selected from X-3204 dispersant) are added, and then 20, 30 or 40 fibers (the fibers can be the second type of fiber or the third type of fiber, wherein the second type of fiber is ton bag fiber, which is transparent and flat and round, the length of the second type of fiber is 1000 micrometers, and the diameter of the second type of fiber is 20 micrometers; the third type of fiber is filter core fiber, which is white and circular column-shaped, the length of the third type of fiber is 1000 micrometers, and the diameter of the third type of fiber is 15 micrometers) are added for mixing and stirring, the stirring speed is slowly increased to 200 revolutions per minute (rpm) within 0-3 minutes, and then slowly increased to 500 revolutions per minute (rpm), and continues to stir for 12 minutes, after the stirring is completed, the material in the mixing container 110 is subjected to centrifugal treatment, so that the fibers and the graphite particles 20 are layered, and then the top layer 41 of the slurry 40 is separated out, and the number of fibers in the top layer 41 of the slurry 40 is obtained. The detection results of different fiber concentrations and different types of fibers are as follows in Table 2:

[0167] Table 2

[0168] Wherein, the detection rate is the percentage of the number of fibers detected to the number of fibers actually contained in the graphite powder material.

[0169] From Table 2, it can be seen that, by using the detection method of the present application, in the case of the same quality of fiber-free graphite, detection of different fiber concentrations is carried out, and the detection rate is greater than 90%. It can be seen that the accuracy of the detection method of the present application is high, and it can be well applied to the actual production of graphite powder to well control the quality of the graphite powder and reduce the problem of uneven surface of the negative electrode sheet coated with the graphite powder.

[0170] The technical features of the above-described embodiments can be combined arbitrarily. To make the description concise, all possible combinations of the technical features in the above-described embodiments are not described, but as long as the combinations of the technical features do not exist, they should be considered as the scope of the present disclosure.

[0171] The above-described embodiments only express several embodiments of the present application, and the description is more specific and detailed, but it should not be construed as limiting the scope of the patent application. It should be noted that for ordinary skilled persons in the art, without departing from the concept of the present application, a number of modifications and improvements can be made, which are within the scope of the present application. Therefore, the scope of the patent of the present application should be subject to the appended claims.

Claims

1. A detection method for detecting fibres in a graphite powder; wherein, The detection method comprises: Mixing graphite powder of a preset mass and a water solution of a separating agent of a preset volume to form a slurry, so that the fibers are arranged in layers with graphite particles in the graphite powder, and the fibers are located at a top layer of the slurry and the graphite particles are located at a bottom layer of the slurry; wherein the density of the water solution of the separating agent is less than the density of the graphite particles and greater than the density of the fibers; Separating the top layer of the slurry; Obtaining the number of the fibers in the top layer of the slurry.

2. The detection method according to claim 1, wherein, The water solution of the separating agent is a colorless and transparent solution.

3. The detection method according to claim 2, wherein, The water solution of the separating agent comprises a water solution of zinc chloride.

4. The detection method according to claim 3, wherein, The aqueous zinc chloride solution has a density of 1.5 grams per cubic centimeter (g / cm 3 ) to 1.8 grams per cubic centimeter (g / cm 3 ).

5. The assay of any one of claims 1-4, wherein, The preset mass is a and the preset volume is V, wherein the preset mass and the preset volume satisfy the following condition: V / a≥1.5 milliliter per gram (ml / g).

6. The detection method according to claim 5, wherein, The preset mass and the preset volume satisfy the following condition: 1.5 milliliter per gram (ml / g)≤V / a≤3 milliliter per gram (ml / g).

7. The assay of any one of claims 1-6, wherein, The separating of the top layer of the slurry specifically comprises: The top layer of the slurry is separated by a drainage method.

8. The assay of any one of claims 1-7, wherein, Before the separating of the top layer of the slurry, the detection method further comprises: Adding a flocculating agent into the slurry.

9. The detection method according to claim 8, wherein, The flocculating agent comprises a water-soluble flocculating agent.

10. The detection method according to claim 8, wherein, The mass of water in the water solution of the separating agent is b, and the mass of the added flocculating agent is greater than or equal to 0.002b, and the mass units of the graphite particles and the flocculating agent are grams.

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

12. The detection method according to claim 8, wherein, Before the separating of the top layer of the slurry, the detection method further comprises: The slurry with the added flocculating agent is treated by a centrifugal separation method.

13. The detection method of claim 8, wherein, Before the separating of the top layer of the slurry, the detection method further comprises: The graphite powder, the water solution of the separating agent and the flocculating agent are mixed by stirring.

14. The detection method according to claim 13, wherein, The mixing of the graphite powder, the water solution of the separating agent and the flocculating agent by stirring specifically comprises: The graphite powder, the water solution of the separating agent and the flocculating agent are mixed at a first preset stirring speed for a first preset time; The graphite powder, the water solution of the separating agent and the flocculating agent are mixed at a second preset stirring speed for a second preset time; The first preset stirring speed is less than the second preset stirring speed.

15. The assay of any one of claims 1-14, wherein, Before the separating of the top layer of the slurry, the detection method further comprises: Adding a surfactant into the slurry.

16. The detection method according to claim 15, wherein, The preset mass is a, and the mass of the added surfactant is c; 0.02a≤c≤0.07a, and the mass units of the graphite particles and the surfactant are grams.

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

18. The assay of any one of claims 1-17, wherein, The obtaining of the number of the fibers in the top layer of the slurry specifically comprises: The separated top layer of the slurry flows through a visual cell at a preset speed; A plurality of detection images of the fibers flowing through the visual cell are obtained, and the number of the fibers in the top layer of the slurry is determined according to the plurality of detection images.

19. A detection device, wherein, The detection device is applied to the detection method as claimed in any one of claims 1-18, and the detection device comprises: a mixing container having a mixing cavity for mixing the graphite powder and the aqueous solution of the separating agent; a separating mechanism arranged on the mixing container and used for separating the top layer of the slurry from the mixing cavity; and an acquisition mechanism arranged on one side of the mixing container and used for acquiring the number of the fibers in the top layer of the slurry.

20. The detection device of claim 19, wherein, A top portion of a side wall of the mixing container is provided with a separating outlet in communication with the mixing cavity. The separating mechanism comprises a flow guide member used for guiding the top layer of the slurry to flow out towards the separating outlet.

21. The detection device of claim 20, wherein, The separating mechanism further comprises a gas supply member connected with the flow guide member, and the gas supply member has a gas supply port. The flow guide member has a gas blowing port arranged towards the separating outlet, and the gas blowing port is in communication with the separating outlet and the gas supply port respectively.

22. The detection device of claim 20, wherein, The detection device further comprises a visual cell located outside the mixing container and on one side of the acquisition mechanism. The visual cell has a visual cavity in communication with the separating outlet, and the visual cell is located on the lower side of the separating outlet in a direction parallel to the top portion of the mixing container and pointing to the bottom portion of the mixing container. The visual cell comprises a visual part used for observing the fibers.

23. The detection device of claim 22, wherein, The detection device further comprises: a flow guide pipe having one end in communication with the separating outlet and the other end in communication with the visual cavity; and an ultrasonic disperser arranged on the flow guide pipe.

24. The assay device of claim 22, wherein, The acquisition mechanism comprises a high-speed camera towards the visual part.

25. The assay device of claim 22, wherein, The detection device further comprises: a water inlet mechanism having a water supply port in communication with the mixing cavity; and a water outlet mechanism having a water return port, and the visual cavity is in communication between the separating outlet and the water return port.

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