A battery slurry impurity removal mechanism and a battery slurry processing device

Abstract

The application discloses a battery slurry impurity removing mechanism and a battery slurry processing device, and relates to the technical field of battery manufacturing. The battery slurry impurity removing mechanism comprises a shell and a plurality of magnet groups. The shell has a first direction, and the shell has a first end and a second end oppositely arranged along the first direction. The plurality of magnet groups are stacked in the shell along the first direction, and the magnetic field intensity of the plurality of magnet groups decreases from the first end to the second end. In this way, when the battery slurry impurity removing mechanism adsorbs the magnetic impurities in the battery slurry, the battery slurry impurity removing mechanism can reduce the adsorption of the lithium supplement in the battery slurry due to the decrease of the magnetic field intensity in the adsorption process of the magnetic impurities, so that the content of the lithium supplement in the battery slurry is ensured, and the available capacity of the prepared battery is improved.

Description

Technical Field

[0001] This application belongs to the field of battery manufacturing technology, specifically relating to a battery slurry impurity removal mechanism and battery slurry processing equipment. Background Technology

[0002] Lithium-ion batteries are widely used in small digital appliances, new energy vehicles, and energy storage due to their advantages such as high energy density, high output voltage, long cycle life, and low environmental pollution. Magnetic foreign matter in the positive electrode material of lithium-ion batteries can cause internal short circuits and self-discharge, thus reducing battery safety. Therefore, the content of magnetic foreign matter is an important indicator for evaluating the safety performance of lithium-ion battery positive electrode materials.

[0003] In related technologies, equidistant magnetic rings and rods are usually used to remove magnetic impurities in battery slurry. However, since the lithium replenishing agent in the battery slurry is also magnetic, the equidistant magnetic rings and rods will also adsorb the lithium replenishing agent while adsorbing the magnetic impurities, resulting in the loss of the lithium replenishing agent and affecting the usable capacity of the battery. Utility Model Content

[0004] This application aims to provide a battery slurry impurity removal mechanism and battery slurry processing equipment, which can solve the problem in related technologies that equidistant magnetic rings and rods adsorb lithium replenishing agent while adsorbing magnetic impurities, resulting in the loss of lithium replenishing agent and affecting the usable capacity of the battery.

[0005] To solve the above-mentioned technical problems, this application is implemented as follows:

[0006] In a first aspect, embodiments of this application propose a battery slurry impurity removal mechanism, comprising: a housing and a plurality of magnet groups, the housing having a first direction, the housing having a first end and a second end disposed opposite to each other along the first direction, the plurality of magnet groups being stacked within the housing along the first direction; and the magnetic field strength of the plurality of magnet groups decreasing from the first end to the second end.

[0007] Optionally, the magnet group includes a plurality of magnets, which are stacked and arranged along the first direction, and the magnetic field strength of the plurality of magnets in the magnet group is the same;

[0008] Alternatively, from the first end to the second end, the magnetic field strength of the multiple magnets in the magnet group gradually decreases.

[0009] Optionally, in all the magnets, each magnet has the same cross-sectional area perpendicular to the first direction, and the height of the magnet gradually decreases from the first end to the second end;

[0010] Alternatively, multiple magnets in the same magnet group have the same height along the first direction, and two adjacent magnet groups are respectively a first magnet group and a second magnet group. The first magnet group is located on the side of the second magnet group closer to the first end. The height of the magnets in the first magnet group is H1, and the height of the magnets in the second magnet group is H2, satisfying: H1 > H2.

[0011] Optionally, the battery slurry impurity removal mechanism further includes a magnetizable metal sheet, with the metal sheet disposed between two adjacent magnets.

[0012] Optionally, the plurality of magnet groups include a first magnet group, a second magnet group, and a third magnet group, and the three magnet groups are stacked sequentially from the first end to the second end;

[0013] The magnetic field strength of the first magnet group is H1, which satisfies: 14500Gs≤H1≤15000Gs;

[0014] The magnetic field strength of the second magnet group is H2, which satisfies: 13500Gs≤H2≤14000Gs;

[0015] The magnetic field strength of the third magnet group is H3, which satisfies: 8000Gs≤H3≤9000Gs.

[0016] Optionally, the plurality of magnet groups further includes a fourth magnet group, which is disposed between the second magnet group and the third magnet group along the first direction. The magnetic field strength of the fourth magnet group is H4, satisfying: 9500Gs≤H4≤10000Gs.

[0017] Optionally, the outer peripheral surface of the housing is provided with a groove that extends spirally along the first direction.

[0018] Optionally, the helix angle of the groove is α, satisfying: 30°≤α≤60°.

[0019] The surface roughness of the outer peripheral surface of the shell is Ra, which satisfies: Ra≤0.1μm;

[0020] And / or, the outer peripheral surface of the housing is provided with a coating, the coating being used to reduce the surface energy of the outer surface of the housing.

[0021] Secondly, embodiments of this application propose a battery slurry processing apparatus, comprising: a battery slurry impurity removal mechanism as described in any of the preceding claims, wherein the battery slurry processing apparatus has a flow channel, the battery slurry impurity removal mechanism is disposed within the flow channel, and the battery slurry flows from the first end to the second end.

[0022] In an embodiment of this application, the battery slurry impurity removal mechanism includes a housing and multiple magnet groups. The housing has a first direction and has a first end and a second end disposed opposite to each other along the first direction. The multiple magnet groups are stacked inside the housing along the first direction, and the magnetic field strength of the multiple magnet groups decreases from the first end to the second end. Thus, when the battery slurry impurity removal mechanism adsorbs magnetic impurities in the battery slurry, due to the decreasing magnetic field strength, the mechanism can reduce the adsorption of lithium supplement in the battery slurry during the adsorption process, thereby ensuring the lithium supplement content in the battery slurry and improving the usable capacity of the prepared battery.

[0023] Additional aspects and advantages of this application will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of this application. Attached Figure Description

[0024] The above and / or additional aspects and advantages of this application will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which:

[0025] Figure 1 This is a schematic diagram of a battery slurry impurity removal mechanism according to an embodiment of this application;

[0026] Figure 2 According to the embodiments of this application, along Figure 1 A cross-sectional view of line AA in the middle;

[0027] Figure 3 According to the embodiments of this application, along Figure 1 Another cross-sectional view of line AA in the middle.

[0028] Figure label:

[0029] 1: Shell; 11: First end; 12: Second end; 13: Groove; 2: Magnet group; 20: Magnet; 21: First magnet group; 22: Second magnet group; 23: Third magnet group; 24: Fourth magnet group; 3: Metal sheet; X: First direction. Detailed Implementation

[0030] The embodiments of this application will now be described in detail. Examples of these embodiments are illustrated in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this application, and should not be construed as limiting this application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application.

[0031] The terms "first" and "second" in the specification and claims of this application may explicitly or implicitly include one or more of the features. In the description of this application, unless otherwise stated, "multiple" means two or more. Furthermore, "and / or" in the specification and claims indicates at least one of the connected objects, and the character " / " generally indicates that the preceding and following objects are in an "or" relationship.

[0032] In the description of this application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., indicating the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application.

[0033] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection between two components. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0034] Before explaining the battery slurry impurity removal mechanism and battery slurry processing equipment provided in the embodiments of this application, the application scenarios of the battery slurry impurity removal mechanism and battery slurry processing equipment provided in the embodiments of this application will be specifically described:

[0035] Magnetic impurities in battery slurry pose the following safety hazards: during charging and discharging, they may be attracted, puncture the separator, and cause short circuits or even thermal runaway; they may consume active lithium, reducing battery capacity; and they may also clog the coating die, resulting in defective electrodes. Therefore, removing magnetic impurities is a crucial process step in lithium battery slurry preparation.

[0036] In related technologies, magnetic impurities are generally adsorbed using equidistant magnetic rings and rods (such as 15-ring N35 neodymium iron boron magnets with a spacing of 30 mm and an average magnetic field strength of 12000 Gs). However, this can lead to the simultaneous adsorption of lithium replenishing agents and magnetic impurities. Since lithium replenishing agents can compensate for irreversible lithium loss during the first charge and discharge process, thereby improving the battery's initial coulombic efficiency and overall energy density, the simultaneous adsorption of lithium replenishing agents and magnetic impurities reduces the usable capacity of the prepared battery, affecting the battery's production quality.

[0037] Therefore, this application provides a battery slurry impurity removal mechanism and a battery slurry processing equipment. The following, in conjunction with the accompanying drawings, will describe in detail the battery slurry impurity removal mechanism and battery slurry processing equipment provided in this application through specific embodiments and application scenarios.

[0038] like Figure 1 , Figure 2 and Figure 3 As shown, the battery slurry impurity removal mechanism according to some embodiments of this application includes a housing 1 and a plurality of magnet groups 2. The housing 1 has a first direction X and has a first end 11 and a second end 12 disposed opposite to each other along the first direction X. The plurality of magnet groups 2 are stacked in the housing 1 along the first direction X; and the magnetic field strength of the plurality of magnet groups 2 decreases from the first end 11 to the second end 12.

[0039] In this embodiment, by setting multiple magnet groups 2 in the housing 1, magnetic impurities in the battery slurry can be removed when the battery slurry is processed by the battery slurry impurity removal mechanism. At the same time, the magnetic field strength of the multiple magnet groups 2 decreases from the first end 11 to the second end 12. Thus, during the adsorption of magnetic impurities, the battery slurry impurity removal mechanism can reduce the adsorption of lithium supplement in the battery slurry, thereby ensuring the lithium supplement content in the battery slurry and improving the usable capacity of the prepared battery.

[0040] It should be noted that the first direction X specifically refers to the length direction of the shell 1. When the shell 1 is cylindrical, the first direction X is the axial direction. In actual use, the battery slurry flows from the first end 11 to the second end 12 of the shell 1, that is, the first end 11 of the shell 1 is set at the inlet of the battery slurry. The battery slurry flows through the outer circumference of the shell 1. The multiple magnet groups 2 in the shell 1 can adsorb magnetic impurities in the battery slurry. As the battery slurry flows, the adsorption force of the multiple magnet groups 2 with decreasing magnetic field strength gradually decreases, thereby reducing the adsorption of lithium supplementation agent. This ensures the content of lithium supplementation agent in the battery slurry, so that the usable capacity of the battery prepared using the battery slurry will not be reduced, thus ensuring the production quality of the battery.

[0041] In specific applications, the housing 1 can be made of a smooth metal tube, such as a stainless steel tube. Multiple magnet groups 2 are stacked inside the housing 1 along the first direction X, thereby forming a magnetic field on the outer periphery of the housing 1 to adsorb magnetic impurities in the battery slurry.

[0042] It should be explained that the multiple magnet groups 2 can be any number of 3, 4, 5, etc. The magnetic field strength of the multiple magnet groups 2 decreases from the first end 11 to the second end 12. Specifically, it can be a gradient decrease or an irregular decrease. Those skilled in the art can set it according to actual needs, and this application does not limit it.

[0043] It should be noted that the battery slurry flows from the first end 11 to the second end 12. When the battery slurry is at the first end 11, it contains more magnetic impurities, so the magnetic field strength at the first end 11 is higher to ensure the adsorption capacity of magnetic impurities. However, as the battery slurry flows from the first end 11 to the second end 12, the magnetic impurities are adsorbed by multiple magnet groups 2, so the content of magnetic impurities in the battery slurry decreases at the second end 12. Therefore, the magnetic field strength at the second end 12 is lower, which can adsorb the remaining magnetic impurities and reduce the adsorption of lithium replenishing agent.

[0044] In some embodiments of this application, the average magnetic field strength of the multiple magnet groups 2 is 12000 Gs, thereby ensuring the adsorption effect on magnetic impurities in the battery slurry.

[0045] It should be noted that Gs specifically refers to the unit of magnetic field strength: Gauss.

[0046] like Figure 2 and Figure 3 As shown, in some embodiments of this application, the magnet group 2 includes a plurality of magnets 20, which are stacked and arranged along the first direction X, and the magnetic field strength of the plurality of magnets 20 in the magnet group 2 is the same.

[0047] Alternatively, from the first end 11 to the second end 12, the magnetic field strength of the multiple magnets 20 in the magnet group 2 gradually decreases.

[0048] In this embodiment, the magnet group 2 includes a plurality of magnets 20 stacked along the first direction X. The magnetic field strength of the plurality of magnets 20 in each magnet group 2 is the same, so that the same magnets 20 can be selected in each magnet group 2, which facilitates processing and selection of magnets 20. Alternatively, the magnetic field strength of the plurality of magnets 20 in the magnet group 2 can gradually decrease from the first end 11 to the second end 12, thereby forming a magnetic field with a decreasing trend from the first end 11 to the second end 12, making the decrease in magnetic field strength smoother and avoiding the situation where the magnetic field strength drops sharply and the adsorption force for magnetic impurities is insufficient.

[0049] In specific applications, each magnet group 2 includes multiple magnets 20, such that the magnetic field strength of the multiple magnet groups 2 decreases from the first end 11 to the second end 12. Specifically, it can be set such that the magnetic field strength of the multiple magnets 20 in each magnet group 2 is the same, and the magnetic field strength of the magnets 20 in the magnet group 2 gradually decreases from the first end 11 to the second end 12, thereby forming a magnetic field with a decreasing magnetic field strength from the first end 11 to the second end 12. For example, from the first end 11 to the second end 12, the multiple magnet groups 2 are sequentially the first magnet group, the second magnet group, and the third magnet group. The magnetic field strength of the multiple magnets 20 in the first magnet group is 15000 Gs, the magnetic field strength of the multiple magnets 20 in the second magnet group is 10000 Gs, and the magnetic field strength of the multiple magnets in the third magnet group is 8000 Gs.

[0050] Alternatively, the magnetic field strength of the multiple magnets 20 in each magnet group 2 can be gradually reduced, thus the magnetic field strength of the multiple magnet groups 2 decreases sequentially, forming a magnetic field with a decreasing trend from the first end 11 to the second end 12. For example, from the first end 11 to the second end 12, the multiple magnet groups 2 are sequentially a first magnet group, a second magnet group, and a third magnet group. The first magnet group includes three magnets 20, which are arranged from the first end 11 to the second end 12. The magnetic field strengths of the three magnets are 15000Gs, 14500Gs, and 14000Gs, respectively. The second and third magnet groups are set in the same way, so that the magnets 20 in the multiple magnet groups 2 can form a magnetic field with a gradually decreasing magnetic field strength from the first end 11 to the second end 12, thereby reducing the adsorption of lithium replenishing agent.

[0051] like Figure 2 and Figure 3 As shown, in some embodiments of this application, in all magnets 20, the cross-sectional area of ​​each magnet 20 along the first direction X is equal, and the height of the magnet 20 gradually decreases from the first end 11 to the second end 12.

[0052] In this embodiment of the application, by setting the cross-sectional area of ​​each magnet 20 to be equal along the first direction X, and the height of the magnet 20 gradually decreases from the first end 11 to the second end 12, a magnetic field with a gradually decreasing magnetic field strength can be formed from the first end 11 to the second end 12, which facilitates processing and reduces processing difficulty.

[0053] It should be explained that, in actual processing, permanent magnets are generally selected as the magnet 20 in this application, such as neodymium magnets, and the formula for calculating their magnetic field strength is as shown in Equation 1:

[0054] B0≈B r Equation 1, ×(L / (L+D))

[0055] Where B0 is the surface magnetic field strength of the magnet, measured in Gs or T; B r This refers to remanence, measured in Gs or tons (T). Its specific value is determined by the material; for example, the remanence of a neodymium magnet is B. r ≈1.2T-1.4T, L refers to the length in the magnetization direction, which is the height of the magnet 20 in this application, in mm, and D refers to the dimension perpendicular to the magnetization direction, in mm, specifically the diameter or side length.

[0056] Therefore, it can be deduced from Equation 1 above that when the cross-sectional area of ​​each magnet 20 along the first direction X is equal, the greater the height of the magnet 20, the greater the magnetic field strength. Thus, the height of the magnet 20 gradually decreases, which can form a magnetic field with gradually decreasing magnetic field strength from the first end 11 to the second end 12. In other words, in actual processing, magnets 20 with the same magnetic field strength per unit volume (i.e., magnet materials with the same remanence) can be selected. Thus, when the cross-sectional area along the first direction X is equal, the smaller the height of the magnet 20, the lower the magnetic field strength. Therefore, by setting the height of the magnet 20 to gradually decrease, a magnetic field with gradually decreasing magnetic field strength can be formed, which is convenient for processing.

[0057] like Figure 2 and Figure 3 As shown, in some embodiments of this application, the heights of multiple magnets 20 in the same magnet group 2 along the first direction X are all the same. Two adjacent magnet groups 2 are respectively the first magnet group and the second magnet group. The first magnet group is located on the side of the second magnet group closer to the first end 11. The height of the magnet 20 in the first magnet group is H1, and the height of the magnet 20 in the second magnet group is H2, satisfying: H1 > H2.

[0058] In this embodiment of the application, by setting multiple magnets 20 in the same magnet group 2 to have equal heights along the first direction X, and the height H1 of the magnets 20 in the first magnet group is greater than the height H2 of the magnets 20 in the second magnet group, multiple magnet groups 2 can be formed with the magnetic field strength gradually decreasing from the first end 11 to the second end 12, thereby causing the magnetic field strength of the battery slurry impurity removal mechanism to gradually decrease from the first end 11 to the second end 12, so as to reduce the adsorption of lithium replenishing agent.

[0059] In specific applications, as shown in Equation 1 above, the heights of multiple magnets 20 in the same magnet group 2 along the first direction X are equal, thereby enabling the magnetic field strength of multiple magnets 20 in the same magnet group 2 to be the same. Furthermore, the height H1 of the magnets 20 in the magnet group closer to the first end 11 is greater than the height H2 of the magnets 20 in the magnet group farther from the first end 11, thereby making the magnetic field strength of the magnet group 2 closer to the first end 11 greater and the magnetic field strength of the magnet group 2 farther from the first end 11 smaller. This results in the magnetic field strength of the battery slurry impurity removal mechanism gradually decreasing from the first end 11 to the second end 12.

[0060] Of course, permanent magnets with smaller remanence can be used for the magnets 20 of the magnet group 2 that are far away from the first end 11, so that the magnetic field strength of the multiple magnet groups 2 from the first end 11 to the second end 12 is more different.

[0061] like Figure 2 and Figure 3 As shown, in some embodiments of this application, the battery slurry impurity removal mechanism further includes a magnetizable metal sheet 3, with the metal sheet 3 disposed between two adjacent magnets 20.

[0062] In this embodiment of the application, by providing a magnetizable metal sheet 3 between two adjacent magnets 20, the repulsive force between the two adjacent magnets 20 can be reduced, thereby increasing the magnetic field strength of that part.

[0063] It should be explained that in practical applications, the N poles of two adjacent magnets 20 are set opposite each other, forming NN. A magnetizable metal sheet 3 is placed between two adjacent magnets 20. The magnetic field lines of the magnets 20 are "broken" through the metal sheet 3, thereby reducing the repulsive force between the two adjacent magnets 20. At the same time, it can guide the magnetic field, reduce the leakage magnetic field between the magnets 20, and thus improve the magnetic field strength at that part.

[0064] In specific applications, the metal sheet 3 can be made of magnetizable metal materials such as iron, nickel, and cobalt. Those skilled in the art can make the settings according to actual needs, and this application does not impose any restrictions on this.

[0065] In some embodiments of this application, the plurality of magnets 20 are specifically neodymium iron boron magnets, and the housing 1 is made of stainless steel tube with an outer diameter of 50.8 mm and a thickness of 0.5 mm.

[0066] From the first end 11 to the second end 12, the first to fifth magnets 20 are N52 neodymium iron boron magnets, each magnet 20 has a height of 40mm along the first direction X, and a 0.5mm iron sheet is placed between two adjacent magnets 20; the sixth to eighth magnets 20 are N48 neodymium iron boron magnets, each magnet 20 has a height of 35mm along the first direction X, and a 0.8mm iron sheet is placed between two adjacent magnets 20; the ninth to eleventh magnets 20 are N35 neodymium iron boron magnets, each magnet 20 has a height of 25mm along the first direction X. m, a 1.2mm iron sheet is placed between two adjacent magnets 20; the twelfth to fifteenth magnets 20 are N35 neodymium iron boron magnets, each magnet 20 has a height of 20mm along the first direction X, and a 1.5mm iron sheet is placed between two adjacent magnets 20; the first to fifteenth magnets 20 are stacked in a stainless steel tube from the first end 11 to the second end 12, with the first magnet 20 located at the first end 11 and the fifteenth magnet 20 located at the second end 12, thereby forming the battery slurry impurity removal mechanism described in this application.

[0067] The specific assembly process is as follows:

[0068] Step 1: Place the cleaned stainless steel pipe horizontally on the assembly workbench and fix it in place using a special positioning clamp;

[0069] Step 2: Following the sequence of the high gradient zone at the front, the transition zone in the middle, and the low gradient zone at the rear, alternately insert the magnet 20 and the iron sheet into the stainless steel tube. After inserting each magnet 20 and iron sheet, use a pressure sensor to detect the assembly pressure to ensure a tight assembly with the gap controlled within ±0.02mm.

[0070] Step 3: After assembly, laser seal the two ends of housing 1. A 1.5kW laser welder is used under argon protection. The welding speed is controlled at 5mm / s, and the welding depth is 0.3mm to ensure a good weld seal, free of porosity and cracks. After welding, a penetrant test is performed on the weld, conforming to ISO 3452 requirements.

[0071] like Figure 2 As shown, in some embodiments of this application, the multiple magnet groups 2 include a first magnet group 21, a second magnet group 22 and a third magnet group 23, and the three magnet groups 2 are stacked and arranged sequentially from the first end 11 to the second end 12.

[0072] Among them, the magnetic field strength of the first magnet group 21 is H1, which satisfies: 14500Gs≤H1≤15000Gs;

[0073] The magnetic field strength of the second magnet group 22 is H2, which satisfies: 13500Gs≤H2≤14000Gs;

[0074] The magnetic field strength of the third magnet group 23 is H3, which satisfies: 8000Gs≤H3≤9000Gs.

[0075] In this embodiment, by setting the magnetic field strength H1 of the first magnet group 21, the magnetic field strength H2 of the second magnet group 22, and the magnetic field strength H3 of the third magnet group within a reasonable range, each magnet group has a certain magnetic field strength, which can ensure the adsorption effect on magnetic impurities. At the same time, the magnetic field strength of the first magnet group 21, the second magnet group 22, and the third magnet group 23 is gradually reduced, thereby forming a magnetic field that gradually decreases from the first end 11 to the second end 12, thereby reducing the adsorption of lithium replenishing agent.

[0076] In specific applications, the magnetic field strength H1 of the first magnet group 21 can be set to any value such as 15000Gs, 14800Gs, 14600Gs, 14500Gs, or a range between two arbitrary values; the magnetic field strength H2 of the second magnet group 22 can be set to any value such as 14000Gs, 13800Gs, 13600Gs, 13500Gs, or a range between two arbitrary values; and the magnetic field strength H3 of the third magnet group 23 can be set to any value such as 9000Gs, 9800Gs, 9600Gs, 9500Gs, 9200Gs, 8000Gs, or a range between two arbitrary values.

[0077] In practical applications, a gaussmeter can be used to measure the magnetic field strength at different positions from the first end 11 to the second end 12 of the battery slurry impurity removal mechanism. A measurement point is taken every 10 mm, and the magnetic field strength value is recorded to ensure that the magnetic field strength of each magnet group 2 is set within the preset range and that the gradient decay of the magnetic field strength meets the preset requirements.

[0078] Meanwhile, a three-dimensional magnetic field measurement system can be used to scan the magnetic field distribution around the battery slurry impurity removal mechanism, draw a magnetic field intensity distribution map, and analyze the magnetic field intensity uniformity to ensure that the magnetic field uniformity deviation is within ±5%.

[0079] like Figure 3 As shown, in some embodiments of this application, the plurality of magnet groups 2 further includes a fourth magnet group 24. Along the first direction X, the fourth magnet group 24 is disposed between the second magnet group 22 and the third magnet group 23. The magnetic field strength of the fourth magnet group 24 is H4, which satisfies: 9500Gs≤H4≤10000Gs.

[0080] In this embodiment, by setting a fourth magnet group 24 between the second magnet group 22 and the third magnet group 23, and setting the magnetic field strength H4 of the fourth magnet group 24 within a reasonable range, the magnetic field strength of the first magnet group 21, the second magnet group 22, the fourth magnet group 24 and the third magnet group 23 can be gradually reduced, so as to reduce the adsorption of lithium replenishing agent while ensuring the adsorption capacity of magnetic impurities, and at the same time make the attenuation of magnetic field strength smoother.

[0081] In specific applications, the magnetic field strength H4 of the fourth magnet group 24 can be set to any value such as 10000Gs, 9800Gs, 9600Gs, 9500Gs, or a range between two arbitrary values.

[0082] like Figure 1 As shown, in some embodiments of this application, the outer peripheral surface of the housing 1 is provided with a groove 13 that extends spirally along the first direction X.

[0083] In this embodiment of the application, by providing a groove 13 extending spirally along the first direction X on the outer peripheral surface of the housing 1, the battery slurry flowing through the outer peripheral surface of the housing 1 can be disturbed, thereby reducing the flow rate of the battery slurry on the outer peripheral surface of the housing 1 and improving the adsorption effect on magnetic impurities.

[0084] In specific applications, the spirally extended grooves 13 on the outer periphery of the housing 1 can cause the flowing battery slurry to form turbulence, thereby mixing laminar and turbulent flow, reducing the flow rate of the battery slurry in this area, and thus improving the adsorption efficiency of magnetic impurities and the uniformity of magnetic impurity adsorption.

[0085] like Figure 1 As shown, in some embodiments of this application, the helix angle of the groove 13 is α, which satisfies: 30°≤α≤60°.

[0086] In this embodiment, by setting the helix angle α of the groove 13 within a reasonable range, the disturbance effect of the groove 13 on the battery slurry can be guaranteed, thereby improving the adsorption effect on magnetic impurities.

[0087] It should be explained that when the helix angle α of the groove 13 is less than 30°, it is not convenient to process, while when the helix angle α of the groove 13 is greater than 60°, the groove 13 has a poor disturbance effect on the battery slurry.

[0088] In specific applications, the helix angle α of the groove 13 can be set to any value such as 30°, 40°, 50°, 60°, or a range between two arbitrary values.

[0089] In actual processing, taking a stainless steel pipe with an outer diameter of 50.8mm as an example, the following parameters can be processed on the outer circumference of the shell 1: groove depth: 0.15±0.02mm, groove width: 0.5±0.05mm, pitch: 8±0.1mm, and helix angle α gradually changes from 60° at the inlet to 30° at the outlet.

[0090] After machining, the bottom of the groove 13 is subjected to nanocrystalline strengthening treatment. The Fe-18Cr-12Ni-2Mo nanocrystalline strip is fused with the material at the bottom of the groove 13 by laser irradiation. After fusion, the hardness of the cladding layer is tested with a hardness tester to ensure that the hardness uniformity is within ±5%.

[0091] like Figure 1 As shown, in some embodiments of this application, the surface roughness of the outer peripheral surface of the housing 1 is Ra, which satisfies: Ra≤0.1μm.

[0092] In this embodiment of the application, by setting the surface roughness Ra of the outer peripheral surface of the shell 1 within a reasonable range, the adsorption probability of lithium replenishing agent can be reduced, thereby ensuring the content of lithium replenishing agent in the battery slurry.

[0093] In practical applications, a high-precision polishing machine can be used to mirror polish the outer peripheral surface of the housing 1 to ensure that the surface roughness Ra of the outer peripheral surface of the housing 1 is within a reasonable range.

[0094] Specifically, the surface roughness Ra of the outer peripheral surface of the shell 1 can be set to any value such as 0.1μm, 0.09μm, 0.08μm, 0.07μm, 0.06μm, or a range between two arbitrary values.

[0095] In practical use, the assembled battery slurry impurity removal mechanism is mounted on a high-precision polishing machine for polishing. After polishing, a surface roughness meter is used to detect the surface roughness Ra of the outer peripheral surface of the housing 1, ensuring that the surface roughness Ra of the outer peripheral surface of the housing 1 is ≤0.1μm (compliant with GB / T 1031 standard). An optical microscope is then used to observe the surface micromorphology to ensure that the surface is free of scratches and pits.

[0096] like Figure 1 As shown, in some embodiments of this application, the outer peripheral surface of the housing 1 is provided with a coating, which is used to reduce the surface energy of the outer surface of the housing 1.

[0097] In this embodiment of the application, by providing a coating (not shown in the figure) that reduces surface energy on the outer peripheral surface of the housing 1, the adsorption capacity of the outer peripheral surface of the housing 1 can be reduced, thereby reducing the adsorption of lithium replenishing agent.

[0098] In practical applications, surface energy refers to the physical quantity in which atoms or molecules on the surface of a material have higher energy than atoms inside the material, directly affecting the material's wettability, adsorption, catalysis, fracture behavior, etc.

[0099] In practical applications, the coating is specifically a diamond-like carbon (DLC) coating. The DLC coating is deposited on the outer surface of the housing 1 using a physical vapor deposition (PVD) system. After deposition, the coating thickness is measured using a profilometer to ensure it is 2 ± 0.2 μm. The water droplet contact angle on the coating surface is measured using a contact angle meter to ensure it is ≥105° and the surface energy is ≤20 mN / m.

[0100] In some embodiments of this application, the battery slurry impurity removal mechanism may also be subjected to the following tests:

[0101] Battery slurry impurity removal test:

[0102] The specific experimental method was conventional magnetic separation, which will not be elaborated here. A simulated battery slurry was prepared, with a ferromagnetic impurity content of 100 ppm and a lithium supplement content of 1%. The slurry was passed through a battery slurry impurity removal mechanism at a flow rate of 0.3 m / s and circulated for 1 hour.

[0103] After processing, the content of ferromagnetic impurities in the slurry was detected using inductively coupled plasma mass spectrometry (ICP-MS), and the iron impurity capture rate was calculated. Simultaneously, the content of the lithium supplement was detected using chemical analysis, and the lithium supplement adsorption capacity was calculated.

[0104] It can be concluded that the iron impurity capture rate is ≥99.5%, and the lithium adsorption capacity is ≤0.08%.

[0105] In some embodiments of this application, a battery slurry processing apparatus is also proposed, including: a battery slurry impurity removal mechanism as described in any of the above embodiments, the battery slurry processing apparatus having a flow channel, the battery slurry impurity removal mechanism being disposed in the flow channel, and the battery slurry flowing from the first end 11 to the second end 12.

[0106] In this embodiment, the battery slurry impurity removal mechanism includes a housing 1 and multiple magnet groups 2. The housing 1 has a first direction X and has a first end 11 and a second end 12 disposed opposite to each other along the first direction X. The multiple magnet groups 2 are stacked inside the housing 1 along the first direction X; and the magnetic field strength of the multiple magnet groups 2 decreases from the first end 11 to the second end 12. Therefore, during the adsorption of magnetic impurities, the battery slurry impurity removal mechanism can reduce the adsorption of lithium supplement in the battery slurry, thereby ensuring the lithium supplement content in the battery slurry and improving the usable capacity of the prepared battery.

[0107] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0108] Although embodiments of this application have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of this application, the scope of which is defined by the claims and their equivalents.

Claims

1. A battery slurry impurity removal mechanism, characterized in that, include: The housing (1) and a plurality of magnet groups (2) are provided. The housing (1) has a first direction (X). The housing (1) has a first end (11) and a second end (12) disposed opposite to each other along the first direction (X). The plurality of magnet groups (2) are stacked in the housing (1) along the first direction (X). The magnetic field strength of the plurality of magnet groups (2) decreases from the first end (11) to the second end (12).

2. The battery slurry impurity removal mechanism according to claim 1, characterized in that, The magnet group (2) includes a plurality of magnets (20), which are stacked and arranged along the first direction (X), and the magnetic field strength of the plurality of magnets (20) in the magnet group (2) is the same; Alternatively, from the first end (11) to the second end (12), the magnetic field strength of the plurality of magnets (20) in the magnet group (2) gradually decreases.

3. The battery slurry impurity removal mechanism according to claim 2, characterized in that, In all the magnets (20), each magnet (20) has the same cross-sectional area along the first direction (X), and the height of the magnet (20) gradually decreases from the first end (11) to the second end (12); Alternatively, multiple magnets (20) in the same magnet group (2) have the same height along the first direction (X), and two adjacent magnet groups (2) are respectively the first magnet group and the second magnet group. The first magnet group is located on the side of the second magnet group closer to the first end (11). The height of the magnet (20) in the first magnet group is H1, and the height of the magnet (20) in the second magnet group is H2, satisfying: H1 > H2.

4. The battery slurry impurity removal mechanism according to claim 2, characterized in that, The battery slurry impurity removal mechanism also includes a magnetizable metal sheet (3), which is disposed between two adjacent magnets (20).

5. The battery slurry impurity removal mechanism according to any one of claims 1-4, characterized in that, The plurality of magnet groups (2) include a first magnet group (21), a second magnet group (22) and a third magnet group (23), and the three magnet groups (2) are stacked in sequence from the first end (11) to the second end (12); The magnetic field strength of the first magnet group (21) is H1, which satisfies: 14500Gs≤H1≤15000Gs; The magnetic field strength of the second magnet group (22) is H2, which satisfies: 13500Gs≤H2≤14000Gs; The magnetic field strength of the third magnet group (23) is H3, which satisfies: 8000Gs≤H3≤9000Gs.

6. The battery slurry impurity removal mechanism according to claim 5, characterized in that, The plurality of magnet groups (2) further includes a fourth magnet group (24) along the first direction (X). The fourth magnet group (24) is located between the second magnet group (22) and the third magnet group (23). The magnetic field strength of the fourth magnet group (24) is H4, which satisfies: 9500Gs≤H4≤10000Gs.

7. The battery slurry impurity removal mechanism according to claim 1, characterized in that, The outer peripheral surface of the housing (1) is provided with a groove (13) extending spirally along the first direction (X).

8. The battery slurry impurity removal mechanism according to claim 7, characterized in that, The helix angle of the groove (13) is α, which satisfies: 30°≤α≤60°.

9. The battery slurry impurity removal mechanism according to claim 1, characterized in that, The surface roughness of the outer peripheral surface of the shell (1) is Ra, which satisfies: Ra≤0.1μm; And / or, the outer peripheral surface of the housing (1) is provided with a coating, the coating being used to reduce the surface energy of the outer surface of the housing (1).

10. A battery slurry processing equipment, characterized in that, include: The battery slurry impurity removal mechanism according to any one of claims 1-9, wherein the battery slurry processing equipment has a flow channel, the battery slurry impurity removal mechanism is disposed in the flow channel, and the battery slurry flows from the first end (11) to the second end (12).

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