Magnetic assembly for pole piece coating and pole piece coating system

Abstract

The utility model discloses a magnetic assembly for pole piece coating and a pole piece coating mechanism, the magnetic assembly comprises a magnet unit, the magnet unit comprises: a first magnet having a first magnetic field direction; a second magnet having a second magnetic field direction; the magnetism gathering material layer is arranged between the first magnet and the second magnet; wherein the direction of the first magnetic field is opposite to the direction of the second magnetic field. Compared with the prior art, the magnetic assembly coated with the pole piece is provided with the first magnet and the second magnet in a stacked mode, the magnetism gathering material layer is additionally arranged between the first magnet and the second magnet, higher magnetic field intensity can be provided, a magnetic field area meeting the requirement is larger, it is guaranteed that graphite particles can be magnetized better, and the magnetic assembly coated with the pole piece is more stable in performance. The included angle between the graphite particles is close to 180 degrees, and the expansion rate of the battery cell in the vertical direction is reduced.

Description

Technical Field

[0001] This utility model relates to the field of secondary battery technology, specifically to a magnetic component and electrode coating system for electrode coating. Background Technology

[0002] In the manufacturing process of lithium-ion batteries, the performance of the anode material has a significant impact on the overall performance of the battery. As a crucial component of the lithium-ion battery anode, the quality and performance of the graphite slurry directly affect the battery's charge-discharge efficiency, cycle stability, and safety. Graphite particles, as the main component of the graphite slurry, play a decisive role in the overall performance of the anode material due to their physical and chemical properties.

[0003] The dispersibility, conductivity, and bonding strength of graphite particles in negative electrode graphite slurry are key factors affecting the performance of the negative electrode. However, traditional graphite particle preparation processes often neglect the important step of magnetization. Magnetization refers to the process by which a material acquires magnetic properties under the influence of an external magnetic field. For graphite particles, magnetization not only improves their dispersibility but also enhances their conductivity and bonding strength with other materials.

[0004] In existing technologies, during the magnetization process of coated graphite slurry, the magnetic field strength of the permanent magnet and the required magnetic field area directly affect the magnetization effect on the graphite particles, which in turn affects the expansion direction of the battery cell, leading to foil breakage. Magnetization of graphite particles mainly involves placing the graphite-coated foil under a permanent magnet and applying a magnetic field of a certain strength to the graphite particles, causing them to deflect under the influence of the magnetic field, with the angle of deflection approaching 180°.

[0005] Currently, there are many magnetization devices for graphite particles, but most permanent magnet devices have a very small magnetic field area that meets the requirements. In the end, only a portion of the graphite is magnetized, while some graphite particles are not magnetized because the magnetic field strength or the area that meets the magnetic field strength is not large enough. Ultimately, the unmagnetized areas will crack due to vertical expansion.

[0006] In view of this, it is indeed necessary to provide a technical solution to the above problems. Utility Model Content

[0007] One of the objectives of this invention is to provide a magnetic component for electrode coating that addresses the shortcomings of existing technologies, possessing better magnetization and stronger magnetic field strength, and is better able to magnetize graphite particles.

[0008] To achieve the above objectives, the present invention adopts the following technical solution:

[0009] A magnetic assembly for electrode coating includes a magnet unit, the magnet unit comprising:

[0010] A first magnet has a first magnetic pole and a second magnetic pole with the opposite magnetic properties to the first magnetic pole, and the first magnet has a first magnetic field direction;

[0011] The second magnet, stacked on top of the first magnet, has a third magnetic pole and a fourth magnetic pole with the opposite magnetic properties to the third magnetic pole, and the second magnet has a second magnetic field direction;

[0012] A magnetic material layer is disposed between the first magnet and the second magnet;

[0013] The direction of the first magnetic field is opposite to that of the second magnetic field.

[0014] Preferably, the number of magnet units is N, where N≥2; multiple magnet units are stacked together, and adjacent magnet units are connected by the magnetic material layer.

[0015] Preferably, the direction of the first magnetic field is from the first magnetic pole to the second magnetic pole; the direction of the second magnetic field is from the fourth magnetic pole to the third magnetic pole.

[0016] Preferably, the first magnetic pole is the S pole, the second magnetic pole is the N pole, the third magnetic pole is the N pole, and the fourth magnetic pole is the S pole.

[0017] Preferably, the magnetic material is one of ferrite stainless steel, low carbon steel, and iron-cobalt alloy.

[0018] Preferably, the magnetic field strengths of the first magnet and the second magnet are equal, and the magnetic field strengths of the first magnet and the second magnet are both 1340-1370 mT.

[0019] Preferably, both the first magnet and the second magnet are permanent magnets.

[0020] Preferably, the first magnet and the second magnet have the same shape and size.

[0021] Preferably, the first magnet and the second magnet are at least one of cuboid, cube, cylinder, and prism.

[0022] The second objective of this utility model is to provide an electrode coating system, including the aforementioned magnetic components for electrode coating.

[0023] Compared with the prior art, the beneficial effects of this utility model are as follows: The magnetic component of the electrode coating provided by this utility model provides a first magnet and a second magnet by stacking them, and a magnetic material layer is added between the first magnet and the second magnet. This can provide a stronger magnetic field strength and a larger magnetic field area to meet the requirements, ensuring that the graphite particles can be better magnetized, so that the included angle between the graphite particles is close to 180°, reducing the vertical expansion rate of the cell. When the included angle between the graphite particles is close to 180°, the expansion of graphite during the charging and discharging process of the battery can be reduced. In addition, the magnetization treatment can reduce the anisotropy of the graphite particles of the electrode and increase the I(004) / I(110) intensity ratio in the lattice, thereby reducing the diffusion resistance of the magnetized electrode and improving the rate and cycle performance of the battery. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the structure of a magnetic component according to an embodiment of the present invention;

[0025] Figure 2 This is a schematic diagram of the structure of a magnetic component according to another embodiment of the present invention.

[0026] Among them, 1 is the first magnet; 2 is the second magnet; and 3 is the magnetic material layer. Detailed Implementation

[0027] To make the technical solution and advantages of this utility model clearer, the present utility model and its beneficial effects will be described in more detail below in conjunction with specific embodiments, but the embodiments of this utility model are not limited thereto.

[0028] The terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature.

[0029] The first aspect of this utility model aims to provide a magnetic assembly for electrode coating, including a magnet unit, the magnet unit comprising:

[0030] The first magnet 1 has a first magnetic pole and a second magnetic pole with the opposite magnetic properties to the first magnetic pole, and the first magnet 1 has a first magnetic field direction;

[0031] The second magnet 2 is stacked with the first magnet 1, and has a third magnetic pole and a fourth magnetic pole with the opposite magnetic properties to the third magnetic pole. The second magnet 2 has a second magnetic field direction.

[0032] A magnetic material layer 3 is disposed between the first magnet 1 and the second magnet 2;

[0033] The direction of the first magnetic field is opposite to that of the second magnetic field.

[0034] The first magnet 1 and the second magnet 2 of this application are stacked together, which can uniformly deflect graphite particles. They are connected in the middle by a magnetically concentrated ferrite stainless steel material. Due to the magnetic concentration effect of the magnetically concentrated material, the magnetic field strength of the foil can be enhanced and the magnetic induction intensity area that meets the conditions can be larger. The area that meets the magnetic field strength is obviously better than the single permanent magnet scheme.

[0035] The magnetization component of this application is set on the coating system and its main function is to magnetize the graphite material coating after the slurry is coated. Specifically, after the foil is coated with graphite slurry, the foil coated with graphite slurry is placed on the front of the permanent magnet to magnetize it.

[0036] Using the magnetization component of this invention, the graphite in the electrode can be deflected to an angle between graphite particles close to 180°. When the angle between graphite particles is close to 180°, the expansion of graphite during the charging and discharging process of the battery can be reduced. Furthermore, the magnetization treatment can reduce the anisotropy of graphite particles in the electrode and increase the I(004) / I(110) intensity ratio in the lattice, thereby reducing the diffusion resistance of the magnetized electrode and improving the rate and cycle performance of the battery.

[0037] In one embodiment of this application, the number of magnet units is N, where N≥2; multiple magnet units are stacked together, and adjacent magnet units are connected by the magnetic material layer 3. The number of magnet units can be adjusted according to the actual coating machine, and can be freely adjusted to the number of units that can deflect all the graphite particles on the coating machine.

[0038] In one embodiment of this application, the direction of the first magnetic field is from the first magnetic pole to the second magnetic pole; the direction of the second magnetic field is from the fourth magnetic pole to the third magnetic pole.

[0039] In one embodiment of this application, the first magnetic pole is the S pole, the second magnetic pole is the N pole, the third magnetic pole is the N pole, and the fourth magnetic pole is the S pole. Due to the basic law of magnetic field interaction that like poles repel and unlike poles attract, the magnetic poles of adjacent permanent magnets should be arranged with the N poles and S poles facing each other.

[0040] In one embodiment of this application, the magnetic material is one of ferrite stainless steel, low-carbon steel, and iron-cobalt alloy. The magnetic material layer 3 enhances the magnetic induction intensity, increases the area of ​​the magnetic field strength region that meets the conditions, allows the graphite particles to be magnetized better, reduces vertical expansion, and can reduce foil breakage caused by vertical expansion.

[0041] In one embodiment of this application, the magnetic field strengths of the first magnet 1 and the second magnet 2 are equal, both being 1340–1370 mT. For example, the magnetic field strength and magnetic field region of a permanent magnet directly affect the magnetization effect on graphite particles, thereby affecting the expansion direction of the battery cell and causing the foil to rupture.

[0042] In one embodiment of this application, both the first magnet 1 and the second magnet 2 are permanent magnets. The permanent magnet material includes at least one of AlNiCo permanent magnet alloys, IronChromiumCo permanent magnet alloys, barium ferrite stainless steel, Strontium ferrite stainless steel, rare earth cobalt permanent magnet materials, and Neodymium Iron Boron permanent magnet materials. Permanent magnets can maintain their magnetism for a long time and are not easily demagnetized by external environmental interference. This long-term stable magnetism makes permanent magnets an ideal choice for many devices requiring a persistent magnetic field.

[0043] In one embodiment of this application, the first magnet 1 and the second magnet 2 have the same shape and size, which can uniformly magnetize the graphite particles on the electrode, thereby uniformly deflecting the graphite particles so that the included angle between the graphite particles on the electrode is close to 180°.

[0044] In one embodiment of this application, the first magnet 1 and the second magnet 2 are at least one of cuboids, cubes, cylinders, and prisms. To ensure uniform magnetization of the graphite particles on the pole pieces, at least one of cuboids, cubes, cylinders, and prisms is preferred.

[0045] According to a second aspect of the present invention, an electrode coating system includes a storage tank, a feed pipe, a return pipe, a return throttle valve, a return valve, a screw pump, a filter, a coating valve, a die head, an exhaust pipe, a back roller, and a magnetizing component of any one of the above.

[0046] The coated electrode is placed under the magnetic assembly, ensuring it is completely covered by the magnetic field. Under the influence of the magnetic field, the graphite particles in the electrode align with the direction of the magnetic field. This alignment reduces the internal resistance of the battery during operation and improves its conductivity.

[0047] The magnetized graphite particles need to maintain their relative positions to preserve the performance of the battery electrodes. To achieve this, the magnetized electrodes need to be dried and shaped. During the drying process, the relative positions of the magnetized graphite particles are fixed, ensuring the stability and consistency of the electrodes.

[0048] The design of the entire system needs to ensure that the coating device and the magnetic components work together so that the electrode can be dried immediately after magnetization to avoid the magnetic field from having an adverse effect on the uncured electrode.

[0049] Based on the disclosure and teachings of the above specification, those skilled in the art can make changes and modifications to the above embodiments. Therefore, this utility model is not limited to the specific embodiments described above, and any obvious improvements, substitutions, or modifications made by those skilled in the art based on this utility model are within the protection scope of this utility model. Furthermore, although some specific terms are used in this specification, these terms are only for convenience of explanation and do not constitute any limitation on this utility model.

Claims

1. A magnetic assembly for pole piece coating, characterized by, The magnetic assembly comprises a magnet unit, the magnet unit comprises: a first magnet (1) having a first magnetic pole and a second magnetic pole opposite to the first magnetic pole, the first magnet (1) having a first magnetic field direction; a second magnet (2) stacked with the first magnet (1), having a third magnetic pole and a fourth magnetic pole opposite to the third magnetic pole, the second magnet (2) having a second magnetic field direction; a magnetic material layer (3) arranged between the first magnet (1) and the second magnet (2), the magnetic material in the magnetic material layer (3) being one of ferrite stainless steel, low carbon steel and iron-cobalt alloy; wherein the first magnetic field direction is opposite to the second magnetic field direction, the number of the magnet units is N, N>2, a plurality of the magnet units are stacked, and adjacent two of the magnet units are connected by the magnetic material layer (3).

2. The magnetic assembly for pole piece coating of claim 1, wherein, The first magnetic field direction is from the first magnetic pole to the second magnetic pole; and the second magnetic field direction is from the fourth magnetic pole to the third magnetic pole.

3. The magnetic assembly for pole piece coating of claim 1, wherein, The first magnetic pole is an S pole, and the second magnetic pole is an N pole; the third magnetic pole is an N pole, and the fourth magnetic pole is an S pole.

4. The magnetic assembly for pole piece coating of claim 1, wherein, The magnetic field intensity of the first magnet (1) and the second magnet (2) is equal, and the magnetic field intensity of the first magnet (1) and the second magnet (2) is 1340-1370mT.

5. The magnetic assembly for pole piece coating of claim 1, wherein, The first magnet (1) and the second magnet (2) are permanent magnets.

6. The magnetic assembly for pole piece coating of claim 1, wherein, The first magnet (1) and the second magnet (2) are the same in shape and size.

7. The magnetic assembly for pole piece coating of claim 1, wherein, The first magnet (1) and the second magnet (2) are at least one of cuboid, square, cylinder and prism.

8. A pole piece coating system characterized by, The magnetic assembly for pole piece coating comprises any one of claims 1-7.

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