Slurry filtering and demagnetizing device and using method thereof

Abstract

The invention discloses a slurry filtering and demagnetizing device, the slurry is used for preparing a battery active material, the device comprises a filter element assembly, an accommodating cavity and an ultrasonic generator, and the device has a filtering and demagnetizing mode and a cleaning mode. By the adoption of the technical scheme, slurry can be filtered and demagnetized, the filter element and the magnetic adsorption component can be cleaned in a cleaning mode after filtering and demagnetizing are completed, the filter element and the magnetic adsorption component do not need to be disassembled and assembled in the whole process, and the production efficiency is greatly improved. In addition, the filter element and the magnetic adsorption component are integrated into one slurry filtering and demagnetizing device, so that the cost is reduced, and the occupied area is also reduced. The invention further discloses a using method of the slurry filtering and demagnetizing device. The method comprises the steps of feeding, filtering and demagnetizing and cleaning. The method is convenient and simple to operate, the production efficiency is greatly improved, and meanwhile, good filtering and demagnetizing effects are achieved.

Description

Technical Field

[0001] The invention belongs to the technical field of battery slurry filtration, and in particular relates to a slurry filtration and demagnetization device and a use method thereof. Background Art

[0002] Lithium-ion batteries have the advantages of high voltage, high specific energy (i.e. energy density), many cycles, and long storage time. They are widely used not only in portable electronic devices such as mobile phones, digital cameras, and laptops, but also in large electric devices such as electric vehicles, electric bicycles, and electric tools. With the widespread use, the safety requirements for lithium-ion batteries are becoming increasingly higher.

[0003] In the production process of lithium-ion batteries, it is necessary to prepare various slurries used to prepare battery active materials, such as positive and negative electrode slurries, binder emulsions, conductive agent slurries, and ceramics. There are impurities and magnetic substances in the slurry, which will affect the performance of the battery. Therefore, during the preparation and transportation of the slurry, it is necessary to filter and demagnetize it to obtain a slurry that meets the use requirements.

[0004] However, in the prior art, filtration and demagnetization are often two independent processes. The slurry generally passes through a filtration device to filter out impurities, and then passes through a demagnetization device to remove magnetic substances in the slurry. As the two processes of filtration and demagnetization are carried out, impurity particles will continue to accumulate in the filtration device, and even block the filter mesh, resulting in a decrease in filtration efficiency; magnetic impurities will also continue to accumulate in the demagnetization device, reducing the demagnetization effect. Therefore, it is necessary to clean the filtration device and the demagnetization device in time to remove these blockages and restore their filtration efficiency and demagnetization efficiency.

[0005] When cleaning, the device is often offline, that is, the entire process of preparing and transporting the slurry needs to be stopped, and the filter element in the filter device and the magnetic adsorption components in the demagnetization device, such as magnetic bars, need to be taken out and cleaned. After cleaning, they are reinstalled and continued to be used. Since they need to be disassembled and installed continuously, the operation process is relatively cumbersome. In addition, the filter device and the demagnetization device occupy a large area and are also costly. Summary of the invention

[0006] The present invention provides the following technical solutions to solve the above technical problems.

[0007] The present invention provides a slurry filtering and demagnetizing device, wherein the slurry is a slurry for preparing battery active materials, and the device comprises:

[0008] Filter element assembly, including:

[0009] A filter element, the interior of which can accommodate slurry and is used for filtering the slurry;

[0010] The magnetic adsorption component is located in the filter element and is used to adsorb magnetic substances in the slurry;

[0011] The accommodating chamber includes a discharge port, and the filter element assembly is located in the accommodating chamber;

[0012] An ultrasonic generator acts in the containing cavity;

[0013] The slurry filtration and demagnetization device has:

[0014] Filtration and demagnetization mode: The slurry is filtered and demagnetized through the filter element assembly to obtain a finished product, which flows out of the filter element assembly and is discharged through the discharge port;

[0015] Cleaning mode: the containing cavity contains the cleaning liquid, the filter element assembly is immersed in the cleaning liquid, the ultrasonic generator ultrasonically cleans the filter element assembly through the cleaning liquid to obtain cleaning waste, and the cleaning waste is discharged through the discharge port.

[0016] By adopting the above technical solution, the filter element and the magnetic adsorption component are "combined into one" into a slurry filtering and demagnetizing device, which reduces production costs and reduces floor space. The slurry filtering and demagnetizing device can not only filter the slurry but also demagnetize the slurry. After filtering and demagnetizing, the filter element and the magnetic adsorption component can be cleaned through the cleaning mode. The whole process does not require the removal and installation of the filter element and the magnetic adsorption component, which greatly improves production efficiency. Furthermore, the ultrasonic cleaning method is selected to clean the filter element and the magnetic adsorption component, which has a good cleaning effect, prolongs the service life of the filter element and the magnetic adsorption component, and reduces the replacement frequency.

[0017] Optionally, the accommodating cavity has a side wall, and a heating component is embedded in the side wall, and the heating component is used to heat the accommodating cavity.

[0018] Optionally, a protrusion is provided at the bottom of the filter element assembly, and a groove is provided at the bottom of the accommodating cavity. The filter element assembly is fixed in the accommodating cavity by snapping the protrusion into the groove.

[0019] Optionally, the slurry filtering and demagnetizing device further comprises a finished product receiving device and a waste receiving device, wherein the finished product receiving device is used to receive finished products, and the waste receiving device is used to receive cleaning waste;

[0020] The discharge port includes a first discharge port and a second discharge port, the first discharge port is connected to the finished product receiving device, and the second discharge port is connected to the waste receiving device; or,

[0021] A conversion valve is provided on the discharge port, and the conversion valve is used to control the switching between the discharge port being separately connected to the finished product receiving device and the discharge port being separately connected to the waste receiving device.

[0022] Optionally, it also includes an upper cover, the accommodating cavity has an opening, the upper cover covers the accommodating cavity, and the upper cover is provided with a feed port, which is connected to the interior of the filter element assembly.

[0023] Optionally, the filter element has a mesh size of 80-200 meshes.

[0024] Optionally, the magnetic adsorption component is a magnetic bar, and there are 2 to 12 magnetic bars, wherein the magnetic induction intensity of each magnetic bar is 5000 to 15000 GS.

[0025] The present invention also provides a method for using the slurry filtering and demagnetizing device, using the slurry filtering and demagnetizing device in each of the above embodiments, the method comprises the following steps:

[0026] Feed: Add slurry into the filter element assembly;

[0027] Filtration and demagnetization: The filter element assembly filters and demagnetizes the slurry to obtain a finished product, which flows out of the filter element assembly and is discharged through the discharge port;

[0028] Cleaning: Add cleaning liquid into the containing cavity, turn on the ultrasonic generator to clean the filter element assembly to obtain cleaning waste, and the obtained cleaning waste is discharged through the discharge port.

[0029] By adopting the above technical scheme, the slurry (battery positive and negative electrode slurry, binder emulsion, conductive agent slurry and ceramic slurry, etc.) can be filtered and demagnetized through the filtering and demagnetization mode, and the filter element and magnetic adsorption components can be cleaned through the cleaning mode after the filtering and demagnetization are completed. The operation is simple and convenient, which greatly improves the production efficiency and has good cleaning and demagnetization effects.

[0030] Optionally, the cleaning step further comprises: cleaning the filter element assembly at a heating temperature of 30-70° C. to obtain cleaning waste, and / or, cleaning the filter element assembly at an ultrasonic power of 0.3-0.6 W / cm 2 The filter element assembly is cleaned under conditions of to obtain cleaning waste, and / or, the filter element assembly is cleaned under conditions of an ultrasonic frequency of 20 to 90 Hz to obtain cleaning waste.

[0031] Optionally, the cleaning solution contains one or more of dimethylformamide (DMF), water (H2O), N-methylformamide (NMF) and N-methyl-2-pyrrolidone (NMP). BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 A schematic diagram showing the structure of an ultrasonic cleaning device in the prior art is shown;

[0033] Figure 2 A schematic diagram showing the structure of a slurry filtering and demagnetizing device according to an embodiment of the present invention;

[0034] Figure 3 A schematic diagram showing the structure of a filter element in one embodiment of the present invention is shown;

[0035] Figure 4 A schematic structural diagram of a magnetic adsorption component in one embodiment of the present invention is shown.

[0036] (Explanation of symbols)

[0037] 1-slurry filtering and demagnetizing device, 2-filter element assembly, 3-filter element, 4-magnetic adsorption component, 5-accommodating chamber, 6-ultrasonic generator, 7-cleaning liquid, 8-discharge port, 9-feed port, 10-upper cover. DETAILED DESCRIPTION

[0038] The following is an explanation of the embodiments of the present invention by specific specific examples, and those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. Although the description of the present invention will be introduced in conjunction with the preferred embodiment, this does not mean that the features of this invention are limited to this embodiment. On the contrary, the purpose of introducing the invention in conjunction with the embodiment is to cover other options or modifications that may be extended based on the claims of the present invention. In order to provide a deep understanding of the present invention, the following description will include many specific details. The present invention can also be implemented without using these details. In addition, in order to avoid confusion or blurring the focus of the present invention, some specific details will be omitted in the description. It should be noted that the embodiments of the present invention and the features in the embodiments can be combined with each other without conflict.

[0039] The terms “first”, “second”, etc. are only used for distinguishing descriptions and should not be understood as indicating or implying relative importance.

[0040] It should be noted that in this specification, similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, it does not need to be further defined and explained in the subsequent drawings.

[0041] In order to make the objectives, technical solutions and advantages of the present invention more clear, the embodiments of the present invention will be further described in detail below with reference to the accompanying drawings.

[0042] like Figure 1-Figure 4 As shown, the present invention provides a slurry filtering and demagnetizing device 1, wherein the slurry is a slurry for preparing battery active materials (such as positive and negative electrode slurry, binder emulsion, conductive agent slurry, etc.), and the slurry filtering and demagnetizing device 1 comprises:

[0043] The filter element assembly 2 comprises:

[0044] A filter element 3, the interior of which can accommodate slurry and is used for filtering the slurry;

[0045] The magnetic adsorption component 4 is located in the filter element 2 and is used to adsorb magnetic substances in the slurry;

[0046] The accommodating chamber 5 includes a discharge port 8, and the filter element assembly 2 is located in the accommodating chamber 5;

[0047] An ultrasonic generator 6 acts in the accommodating cavity 5;

[0048] The slurry filtering and demagnetizing device 1 has:

[0049] Filtration and demagnetization mode: the slurry is filtered and demagnetized through the filter element assembly 2 to obtain a finished product, which flows out of the filter element assembly 2 and is discharged through the discharge port 8;

[0050] Cleaning mode: the accommodating chamber 5 accommodates the cleaning liquid 7, the filter element assembly 2 is immersed in the cleaning liquid 7, the ultrasonic generator 6 ultrasonically cleans the filter element assembly 2 through the cleaning liquid 7 to obtain cleaning waste, and the cleaning waste is discharged through the discharge port 8.

[0051] By adopting the above technical solution, the filter element 3 and the magnetic adsorption component 4 are "combined into one" into a slurry filtering and demagnetizing device 1, which reduces costs and reduces the floor space. The slurry filtering and demagnetizing device 1 can both filter the slurry and demagnetize the slurry. After the filtration and demagnetization are completed, the filter element 3 and the magnetic adsorption component 4 can also be cleaned through the cleaning mode. The whole process does not require the disassembly and installation of the filter element 3 and the magnetic adsorption component 4, which greatly improves the production efficiency. Furthermore, ultrasonic cleaning is selected to clean the filter element assembly 2 and the magnetic adsorption component 4, and the cleaning effect is good, which prolongs the service life of the filter element 3 and the magnetic adsorption component 4 and reduces the replacement frequency.

[0052] Specifically, refer to Figure 2 In the filtering and demagnetizing mode, the flow path of the slurry is "inside-out". After entering the filter element assembly 2, the magnetic substances in the slurry will be adsorbed on the magnetic adsorption component 4 (such as Figure 4 Under the action of pressure, the finished product is removed from the filter element 3 (as shown in FIG. Figure 3 The mesh holes on the filter element 2 are squeezed out, and the impurities are trapped in the filter element assembly 2. The finished product flowing out of the filter element assembly 2 enters the accommodating chamber 5 and is then discharged through the discharge port 8.

[0053] refer to Figure 1 In the cleaning mode, a cleaning liquid 7 can be poured into the accommodating chamber 5. Then the ultrasonic generator 6 is turned on. At this time, the cleaning liquid 7 is used to clean the filter element assembly 2 (such as Figure 2 As shown) is subjected to ultrasonic cleaning to obtain cleaning waste. Figure 3 Combined with Figure 2 The obtained cleaning waste flows out along the mesh holes on the filter element 3 into the accommodating chamber 5 and is then discharged through the discharge port 8.

[0054] Among them, ultrasound is a sound wave with a frequency higher than the upper limit of human hearing (about 20kHz). It relies on elastic media such as liquids, solids or gases during propagation. The propagation of ultrasound causes the particles in the medium to oscillate and transfer energy through the medium in the direction of ultrasound propagation. Among them, the acceleration of particle vibration caused by ultrasound is proportional to the square of the ultrasound frequency, which means that even ultrasound with a frequency of only tens of kilohertz can produce huge forces. Strong ultrasound propagating in liquids can cause acoustic cavitation due to nonlinear effects. When cavitation bubbles suddenly close, they emit shock waves that can generate local high pressures of up to thousands of atmospheric pressures around them. This high pressure directly and repeatedly impacts the object being cleaned, which not only destroys the adsorption force between the dirt and the surface of the cleaning part, but also causes the dirt layer to rupture, causing it to detach from the surface of the cleaning part and disperse into the cleaning liquid. During the vibration process, cavitation bubbles also cause liquid circulation, which is called acoustic streaming. Acoustic streaming forms high velocity gradients and viscous stresses on the surface of the bubbles, which helps to destroy and remove dirt on the surface of the cleaning part. The high-speed micro jets generated by ultrasonic cavitation at the interface between solid and liquid can remove or weaken the boundary dirt layer, even corrode the solid surface, enhance the stirring effect, accelerate the dissolution of soluble dirt, and enhance the effect of chemical cleaning agents. In addition, the speed and acceleration of particle vibration caused by ultrasound in the cleaning liquid are very large, which makes the dirt on the surface of the cleaning piece suffer frequent and violent impacts, thereby effectively cleaning the surface. The present invention adopts ultrasonic cleaning to improve the cleaning effect of the filter element component 2 and effectively remove impurities remaining on the surface of the filter element component 2.

[0055] Furthermore, the accommodating cavity 5 in the above embodiment has a side wall 5.1. A heating component is embedded in the side wall 5.1, and the heating component is used to heat the accommodating cavity 5.

[0056] The study found that in the cleaning mode, turning on the heating component can greatly improve the cleaning effect, extend the service life of the filter element 3 and the magnetic adsorption component 4, and reduce the replacement frequency. Specifically, since the mesh number of the filter element 3 (referring to the number of filter mesh holes per unit length (usually per inch). The higher the mesh number of the filter element 3, the smaller the pore size of the filter mesh) is small, impurities are easily blocked in the mesh, and some impurities can be cleaned under ultrasonic conditions. However, there are still some impurities, such as adhesives, which are tightly adhered to the mesh due to the solidification phenomenon, and it is difficult to clean them through the conventional ultrasonic cleaning mode. This makes the filter element unusable after several ultrasonic cleanings, and a new filter element needs to be replaced. The filter element is expensive, which leads to an increase in production costs. Under heating conditions, these solidified adhesives will be softened or deteriorated, and will dissolve in the cleaning liquid after ultrasonic cleaning, so that the mesh on the filter element 3 is in an open state. This improves the cleaning effect of the filter element 3, extends the service life of the filter element 3, and reduces its replacement frequency.

[0057] It should be noted that the heating component can adopt a variety of different heating methods, such as resistance heating, induction heating, infrared heating or microwave heating, etc. In particular, the heating component is a resistance heating component, such as a heating wire. Resistance heating is used to facilitate precise temperature control.

[0058] The present invention uses heating and ultrasonic cleaning technology, and can utilize the cavitation effect, acceleration effect and straight flow effect of ultrasonic waves in the liquid after heating to directly and indirectly act on the liquid and the suspension, so that the agglomerate layer is dispersed, emulsified and peeled off to achieve the purpose of cleaning, and the device also has a demagnetization function. The device can adopt an offline cleaning method (that is, the whole process of preparing and transporting the slurry is stopped, and the filter element 3 and the magnetic adsorption component 4 are taken out and cleaned), or an online cleaning method 9, that is, an online ultrasonic oscillation cleaning method, that is, after the filtration and demagnetization is completed, the cleaning mode is turned on to clean the filter element assembly 2, which greatly improves the cleaning effect and reduces the cleaning frequency. In addition, periodic online ultrasonic oscillation cleaning during the slurry conveying process can make the filtrate difficult to agglomerate and adhere. In some possible embodiments, the online ultrasonic oscillation is turned on during the slurry conveying process, and the cycle of the online ultrasonic oscillation is 0.2-5 times / minute.

[0059] refer to Figure 2 In some possible embodiments provided by the present invention, a protrusion (not shown in the figure) is provided at the bottom of the filter element assembly 2, and a groove (not shown in the figure) is provided at the bottom of the accommodating chamber 5. The filter element assembly 2 is engaged with the protrusion and the groove to fix the filter element assembly in the accommodating chamber 5. In this way, the filter element assembly 2 can be stably installed in the accommodating chamber 5, and it is also convenient to pull out the filter element assembly 2 to replace or wipe it. After ultrasonic cleaning, most of the magnetic substances adsorbed on the magnetic adsorption component 4 are cleaned away, but a small part of the iron powder adsorbed on the magnetic adsorption component 4 is difficult to be cleaned away by ultrasonic cleaning. After long-term use, it is necessary to pull out the magnetic adsorption component 4 and wipe it with a rag to remove the iron powder. Specifically, a protrusion is provided at the bottom of the filter element 3, and the structure of the protrusion is a cylinder. A cylindrical groove is provided in the accommodating chamber 5, so that the filter element 32 can be fixed in the accommodating chamber 5 by engaging the protrusion and the groove; the magnetic adsorption component 4 can be a plurality of magnetic rods fixed on a disc (such as Figure 4 As shown in FIG. 1 , the disc is made of stainless steel, and a plurality of protrusions are arranged at the bottom of the disc. The protrusions can be arranged in a triangular prism (the bottom surface is a triangle) or a quadrangular prism (the bottom surface is a quadrangle), and a prism-shaped groove that can be engaged with the protrusions is arranged in the receiving cavity 5. Such a protrusion structure has good stability. After the magnetic adsorption component 4 is installed in the receiving cavity 5, it is not easy to slide. At the same time, the structure is also convenient for production and manufacturing.

[0060] Furthermore, the slurry filtering and demagnetizing device 1 in each of the above embodiments also includes a finished product receiving device and a waste receiving device, the finished product receiving device is used to receive finished products, the waste receiving device is used to receive cleaning waste, and the discharge port 8 includes a first discharge port and a second discharge port, the first discharge port is connected to the finished product receiving device, and the second discharge port is connected to the waste receiving device. By setting two different discharge ports (the first discharge port and the second discharge port), the finished product and the cleaning waste can be effectively separated. In this way, the purity and quality of the finished product can be ensured, and the subsequent treatment of the waste can be facilitated. Alternatively, a conversion valve is set on the discharge port 8, and the conversion valve is used to control the switching between the discharge port 8 being connected to the finished product receiving device alone and the discharge port 8 being connected to the waste receiving device alone. This setting allows the discharge port 8 to be flexibly switched between the finished product receiving device and the waste receiving device. Thereby, the process can be adjusted according to production needs, for example, all materials can be directed to the waste receiving device for further processing when necessary.

[0061] Furthermore, the slurry filtering and demagnetizing device 1 in each of the above embodiments further includes an upper cover 10. The accommodating chamber 5 has an opening, and the upper cover 10 covers the accommodating chamber. The upper cover 10 is provided with a feed port 8, and the feed port 8 is connected to the inside of the filter assembly 2. This arrangement can prevent external impurities from entering the filtration system, and can also prevent the slurry from leaking during the filtration process, keeping the working environment clean. At the same time, the inflow speed and flow rate of the slurry can be controlled through the feed port 8, which helps to adjust the workload of the filter assembly 2 and optimize the filtration effect.

[0062] Furthermore, in the above embodiments, the mesh number of the filter element 3 is 80-200 meshes. The mesh number within this range can ensure the cleaning effect, extend the service life of the filter element 3, reduce the replacement frequency, and reduce the maintenance cost.

[0063] Furthermore, if Figure 4 As shown, in the above embodiments, the magnetic adsorption component 4 is a magnetic bar, and there are 2 to 12 magnetic bars. The magnetic induction intensity of each magnetic bar is 5000 to 15000 GS, so that the magnetic material in the slurry can be effectively adsorbed.

[0064] Furthermore, according to production requirements, 1 to 6 filter element assemblies 2 can be connected in series in the filtering and demagnetizing device 1 to further improve the efficiency of filtering and demagnetizing. Furthermore, 1 to 6 filtering and demagnetizing devices can be connected in series to further improve the effect of filtering and demagnetizing.

[0065] The present invention also provides a method for using the slurry filtering and demagnetizing device 1. Using the slurry filtering and demagnetizing device 1 in each of the above embodiments, the method comprises the following steps:

[0066] Feeding: Add slurry into the filter element assembly 2.

[0067] Filtration and demagnetization: The filter element assembly 2 filters and demagnetizes the slurry to obtain a finished product, and the obtained finished product flows out of the filter element assembly 2 and is discharged through the discharge port 8.

[0068] Cleaning: Add cleaning liquid 7 into the accommodating chamber 5, turn on the ultrasonic generator 6 to clean the filter element assembly 2 to obtain cleaning waste, and the obtained cleaning waste is discharged through the discharge port 8.

[0069] By adopting the above technical scheme, the slurry (battery positive and negative electrode slurry, binder emulsion, conductive agent slurry and ceramic slurry) can be filtered and demagnetized through the filtering and demagnetization mode, and the filter element 3 and the magnetic adsorption component 4 can be cleaned through the cleaning mode after the filtering and demagnetization are completed. The operation method is simple and convenient, which greatly improves the production efficiency, and the cleaning and demagnetization effects are good.

[0070] Furthermore, in the above embodiment, the cleaning step also includes: cleaning the filter element assembly 2 under the condition of a heating temperature of 30-70°C to obtain cleaning waste. Studies have found that controlling the temperature at 30-70°C can significantly improve the cleaning effect and reduce the cleaning frequency. For example, the cleaning frequency can be reduced from the original single shift (12h) to once every 7 days, successfully solving the problem of the filter element being difficult to clean during slurry mixing and slurry transportation. Conventional filtering devices include capsule filters and stainless steel filter elements. Capsule filters are disposable filtering devices that cannot be reused and are relatively expensive. Stainless steel filter elements have a high replacement frequency. Although they can be reused, they are difficult to clean and the cleaning effect is difficult to guarantee. The use of this technical solution can effectively solve the problems of poor cleaning effect and difficulty in cleaning. In particular, after filtering and demagnetizing the positive electrode slurry, cleaning the filter element assembly 2 at a temperature of 50-60°C can achieve a better cleaning effect; after filtering and demagnetizing the negative electrode slurry, cleaning the filter element assembly 2 at a temperature of 30-50°C can achieve a better cleaning effect.

[0071] In addition, existing demagnetization devices usually use two methods: permanent magnetic demagnetization and electromagnetic demagnetization. Electromagnetic demagnetization consumes a lot of energy and occupies a large area, so permanent magnetic demagnetization is still the most commonly used. However, permanent magnetic demagnetization is generally difficult to clean, and it is troublesome to disassemble and assemble, and it needs to be stopped for cleaning. The above-mentioned scheme provided by the present invention can ensure the cleaning effect, reduce the frequency of cleaning, and can also be quickly disassembled and cleaned. Since this method only needs to use a filtering demagnetization device 1 to complete filtering demagnetization and cleaning, it can also reduce the floor space.

[0072] Furthermore, when the ultrasonic power is 0.3-0.6 W / cm 2 The filter element assembly 2 is cleaned under conditions to obtain cleaning waste.

[0073] Furthermore, the filter element assembly 2 is cleaned under the condition of an ultrasonic frequency of 20 to 90 Hz to obtain cleaned waste. In particular, the ultrasonic frequency is 50 to 90 Hz.

[0074] Furthermore, in each of the above embodiments, the cleaning liquid 7 contains an oil-based component, and the oil-based component can be selected from one or more of dimethylformamide (DMF), N-methylformamide (NMF) and N-methyl-2-pyrrolidone (NMP). The above three polar solvents have a strong solubility, can dissolve a variety of organic matter, and are suitable for removing impurities in the positive electrode slurry. Studies have found that under the condition of a heating temperature of 30-70°C, the use of the above polar solvents can achieve a better cleaning effect. In particular, the oil-based component in the cleaning liquid 7 is N-methyl-2-pyrrolidone (NMP), and the heating temperature is 50-60°C. In addition, the cleaning liquid may also contain an aqueous component, and the aqueous component may be deionized water, which is particularly suitable for removing impurities in the negative electrode slurry. Studies have found that under the condition of a heating temperature of 30-50°C, a better cleaning effect can be achieved.

[0075] The technical effects of the present invention are further described below in conjunction with embodiments and drawings.

[0076] Example 1

[0077] Selection Figure 2 The device shown (a switching valve is provided on the discharge port 8, the switching valve is used to control the switching between the discharge port 8 being connected to the finished product receiving device alone and the discharge port 8 being connected to the waste receiving device, the magnetic adsorption component is a magnetic rod, and the number of magnetic rods is 10) performs the following steps:

[0078] Feeding: Add slurry into the filter element assembly 2, wherein the slurry is positive electrode lithium iron phosphate slurry.

[0079] Filtration and demagnetization: The filter element assembly 2 filters and demagnetizes the slurry to obtain a finished product, and the obtained finished product flows out of the filter element assembly 2 and is discharged through the discharge port 8;

[0080] Cleaning: Add NMP (cleaning liquid) into the containing chamber 5, turn on the ultrasonic generator 6 and the heating component, wherein the heating temperature is 55°C and the ultrasonic power is 0.5W / cm 2 , the filter element assembly 2 is cleaned under the condition of an ultrasonic frequency of 40 Hz to obtain cleaning waste, and the obtained cleaning waste is discharged through the discharge port 8.

[0081] The production process repeats the above-mentioned feeding, filtering and demagnetizing steps online. The filter element assembly can be cleaned online once according to the cleaning steps during the daily shift change, and the finished product is obtained after filtering and demagnetizing after 2 days.

[0082] Example 2

[0083] Selection Figure 2 The device shown (a switching valve is provided on the discharge port 8, the switching valve is used to control the switching between the discharge port 8 being connected to the finished product receiving device alone and the discharge port 8 being connected to the waste receiving device, the magnetic adsorption component is a magnetic rod, and the number of magnetic rods is 8) performs the following steps:

[0084] Feeding: Add slurry into the filter element assembly 2, wherein the slurry is positive electrode lithium iron phosphate slurry.

[0085] Filtration and demagnetization: The filter element assembly 2 filters and demagnetizes the slurry to obtain a finished product, and the obtained finished product flows out of the filter element assembly 2 and is discharged through the discharge port 8;

[0086] Cleaning: Add NMP (cleaning liquid) into the containing chamber 5, turn on the ultrasonic generator 6 and the heating component, wherein the heating temperature is 55°C and the ultrasonic power is 0.3W / cm 2 , the filter element assembly 2 is cleaned under the condition of an ultrasonic frequency of 30 Hz to obtain cleaning waste, and the obtained cleaning waste is discharged through the discharge port 8.

[0087] The production process repeats the above-mentioned feeding, filtering and demagnetizing steps online. The filter element assembly can be cleaned online once according to the cleaning steps during the daily shift change, and the finished product is obtained after filtering and demagnetizing after 2 days.

[0088] Example 3

[0089] Selection Figure 2 The device shown (a switching valve is provided on the discharge port 8, the switching valve is used to control the switching between the discharge port 8 being connected to the finished product receiving device alone and the discharge port 8 being connected to the waste receiving device, the magnetic adsorption component is a magnetic rod, and the number of magnetic rods is 6) performs the following steps:

[0090] Feeding: Add slurry into the filter element assembly 2, wherein the slurry is positive electrode lithium iron phosphate slurry.

[0091] Filtration and demagnetization: The filter element assembly 2 filters and demagnetizes the slurry to obtain a finished product, and the obtained finished product flows out of the filter element assembly 2 and is discharged through the discharge port 8;

[0092] Cleaning: Add NMP (cleaning liquid) into the containing chamber 5, turn on the ultrasonic generator 6 and the heating component, wherein the heating temperature is 80°C and the ultrasonic power is 0.5W / cm 2 , the filter element assembly 2 is cleaned under the condition of an ultrasonic frequency of 20 Hz to obtain cleaning waste, and the obtained cleaning waste is discharged through the discharge port 8.

[0093] The production process repeats the above-mentioned feeding, filtering and demagnetizing steps online. The filter element assembly can be cleaned online once according to the cleaning steps during the daily shift change, and the finished product is obtained after filtering and demagnetizing after 2 days.

[0094] Example 4

[0095] Selection Figure 2 The device shown (a switching valve is provided on the discharge port 8, the switching valve is used to control the switching between the discharge port 8 being connected to the finished product receiving device alone and the discharge port 8 being connected to the waste receiving device, the magnetic adsorption component is a magnetic rod, and the number of magnetic rods is 6) performs the following steps:

[0096] Feeding: Add slurry into the filter element assembly 2, wherein the slurry is negative electrode graphite slurry.

[0097] Filtration and demagnetization: The filter element assembly 2 filters and demagnetizes the slurry to obtain a finished product, and the obtained finished product flows out of the filter element assembly 2 and is discharged through the discharge port 8;

[0098] Cleaning: Add H2O (cleaning liquid) into the containing chamber 5, turn on the ultrasonic generator 6 and the heating component, wherein the heating temperature is 40°C and the ultrasonic power is 0.5W / cm 2 , the filter element assembly 2 is cleaned under the condition of an ultrasonic frequency of 20 Hz to obtain cleaning waste, and the obtained cleaning waste is discharged through the discharge port 8.

[0099] The production process repeats the above-mentioned feeding, filtering and demagnetizing steps online. The filter element assembly can be cleaned online once according to the cleaning steps during the daily shift change, and the finished product is obtained after filtering and demagnetizing after 2 days.

[0100] Example 5

[0101] Selection Figure 2 The device shown (a switching valve is provided on the discharge port 8, the switching valve is used to control the switching between the discharge port 8 being connected to the finished product receiving device alone and the discharge port 8 being connected to the waste receiving device, the magnetic adsorption component is a magnetic rod, and the number of magnetic rods is 10) performs the following steps:

[0102] Feeding: Add slurry into the filter element assembly 2, wherein the slurry is negative electrode graphite slurry.

[0103] Filtration and demagnetization: The filter element assembly 2 filters and demagnetizes the slurry to obtain a finished product, and the obtained finished product flows out of the filter element assembly 2 and is discharged through the discharge port 8;

[0104] Cleaning: Add H2O (cleaning liquid) into the containing chamber 5, turn on the ultrasonic generator 6 and the heating component, wherein the heating temperature is 40°C and the ultrasonic power is 0.5W / cm 2 , the filter element assembly 2 is cleaned under the condition of an ultrasonic frequency of 50 Hz to obtain cleaning waste, and the obtained cleaning waste is discharged through the discharge port 8.

[0105] The production process repeats the above-mentioned feeding, filtering and demagnetizing steps online. The filter element assembly can be cleaned online once according to the cleaning steps during the daily shift change, and the finished product is obtained after filtering and demagnetizing after 2 days.

[0106] Comparative Example 1

[0107] Use a filtering device (such as Figure 3 as shown) and a demagnetizing device (as Figure 4 As shown, the magnetic adsorption component is a magnetic rod, and the number of magnetic rods is 10) to filter and demagnetize the positive lithium iron phosphate slurry, wherein filtering and demagnetizing are two independent processes, and the filtering device and the demagnetizing device are connected in series. The specific steps are as follows:

[0108] The positive lithium iron phosphate slurry enters the filter device, the filter screen filters the slurry, and then enters the demagnetization device, and the demagnetization device demagnetizes the filtered slurry. The production process lasts for 2 days and then goes offline. The filter device and demagnetization device are manually cleaned, and the finished product is obtained after 2 days of filtration and demagnetization.

[0109] The finished products obtained in the above-mentioned Examples 1-6 were tested, and the magnetic substance content in the finished products was detected by ICP (inductively coupled plasma) test experiment. The filter was removed and rinsed, and the transmittance was observed to determine the pore blockage of the screen. The transmittance refers to the ability of light to pass through the filter. The higher the transmittance, the fewer the pores are blocked, and the better the filtering and cleaning effect. The ICP data (where 1 ppb is equivalent to 1 unit of magnetic substance in 1 billion units of finished products) and the filter transmittance are recorded in the following Table 1.

[0110] Table 1

[0111]

[0112] According to Table 1, within the same use cycle, the slurry filtering and demagnetizing device provided by the present invention can be applied to the filtering and demagnetizing of positive and negative electrode slurries, and also has better self-cleaning effect and demagnetization effect. Compared with Comparative Example 1, in the filtering and demagnetizing mode, the content of magnetic substances in the slurries of Examples 1-5 is significantly reduced, and the demagnetization effect is greatly improved; in the cleaning mode, the light transmittance of the filter screen is significantly increased, and the cleaning effect is significantly improved. In practice, when the light transmittance of the filter element is lower than 50%, it needs to be replaced. The use of the online slurry filtering and demagnetizing device provided by the present invention can make the light transmittance of the filter screen reach more than 80%, which greatly reduces the replacement and cleaning frequency of the filter screen, thereby greatly reducing the manufacturing cost.

[0113] Furthermore, when the positive electrode slurry is filtered and demagnetized and then the slurry filtering and demagnetizing device is cleaned, the cleaning effect of Example 1-2 is better than that of Example 3 because the temperature is further controlled within the range of 50-60°C, which is ultimately reflected in the fact that the light transmittance of Example 1-2 is higher than that of Example 3.

[0114] Furthermore, when filtering and demagnetizing the negative electrode slurry and then cleaning the slurry filtering and demagnetizing device, the cleaning effect of Example 4-5 is better because the temperature is controlled at 30-50°C, and the light transmittance of the filter reaches more than 80%. Furthermore, Example 5 further controls the ultrasonic frequency at 50-90Hz, and its cleaning effect is better than that of Example 4, and the light transmittance of Example 5 is higher than that of Example 4.

[0115] Although the present invention has been illustrated and described with reference to certain preferred embodiments of the present invention, it should be understood by those skilled in the art that the above is a further detailed description of the present invention in conjunction with specific embodiments, and it cannot be determined that the specific implementation of the present invention is limited to these descriptions. Those skilled in the art may make various changes in form and details, including making several simple deductions or substitutions, without departing from the spirit and scope of the present invention.

Claims

1. A slurry filtering and demagnetizing device, wherein the slurry is a slurry for preparing battery active materials, characterized in that: include: Filter element assembly, including: A filter element, the interior of which can accommodate the slurry and is used to filter the slurry; A magnetic adsorption component, located in the filter element, for adsorbing magnetic substances in the slurry; An accommodating chamber, including a discharge port, wherein the filter element assembly is located in the accommodating chamber; An ultrasonic generator acts in the accommodating cavity; The slurry filtering and demagnetizing device comprises: Filtration and demagnetization mode: the slurry is filtered and demagnetized through the filter element assembly to obtain a finished product, which flows out of the filter element assembly and is discharged through the discharge port; Cleaning mode: the containing chamber contains cleaning liquid, the filter element assembly is immersed in the cleaning liquid, the ultrasonic generator ultrasonically cleans the filter element assembly through the cleaning liquid to obtain cleaning waste, and the cleaning waste is discharged through the discharge port.

2. The slurry filtering and demagnetizing device according to claim 1, characterized in that: The accommodating cavity has a side wall, and a heating component is embedded in the side wall. The heating component is used to heat the inside of the accommodating cavity.

3. The slurry filtering and demagnetizing device according to claim 1, characterized in that: The bottom of the filter element assembly is provided with a protrusion, and the bottom of the accommodating cavity is provided with a groove. The filter element assembly is engaged with the groove through the protrusion so that the filter element assembly is fixed in the accommodating cavity.

4. The slurry filtering and demagnetizing device according to claim 1, characterized in that: The slurry filtering and demagnetizing device further comprises a finished product receiving device and a waste receiving device, wherein the finished product receiving device is used to receive the finished product, and the waste receiving device is used to receive the cleaning waste; The discharge port includes a first discharge port and a second discharge port, the first discharge port is connected to the finished product receiving device, and the second discharge port is connected to the waste receiving device; or, The discharge port is provided with a conversion valve, and the conversion valve is used to control the switching between the discharge port being separately connected to the finished product receiving device and the discharge port being separately connected to the waste receiving device.

5. The slurry filtering and demagnetizing device according to claim 1, characterized in that: It also includes an upper cover, the accommodating cavity has an opening, the upper cover covers the accommodating cavity, and the upper cover is provided with a feed port, and the feed port is connected to the interior of the filter element assembly.

6. The slurry filtering and demagnetizing device according to claim 1, characterized in that: The mesh number of the filter element is 80-200 meshes.

7. The slurry filtering and demagnetizing device according to claim 1, characterized in that: The magnetic adsorption component is a magnetic bar, and there are 2 to 12 magnetic bars, wherein the magnetic induction intensity of each magnetic bar is 5000 to 15000 GS.

8. A method for using a slurry filtering and demagnetizing device, characterized in that: Using the slurry filtration and demagnetization device according to any one of claims 1 to 7, the method of using the device comprises the following steps: Feed: Add slurry into the filter element assembly; Filtration and demagnetization: the filter element assembly filters and demagnetizes the slurry to obtain a finished product, and the obtained finished product flows out of the filter element assembly and is discharged through a discharge port; Cleaning: Add cleaning liquid into the containing cavity, turn on the ultrasonic generator to clean the filter element assembly to obtain cleaning waste, and the obtained cleaning waste is discharged through the discharge port.

9. The method according to claim 8, characterized in that The cleaning step further comprises: cleaning the filter element assembly at a heating temperature of 30-70° C. to obtain the cleaning waste, and / or, cleaning the filter element assembly at an ultrasonic power of 0.3-0.6 W / cm 2 The filter element assembly is cleaned under the condition of ultrasonic frequency of 20 to 90 Hz to obtain the cleaning waste.

10. The method according to claim 8, characterized in that The cleaning solution contains one or more of dimethylformamide (DMF), water (H2O), N-methylformamide (NMF) and N-methyl-2-pyrrolidone (NMP).

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