Magnetic assembly for pole piece coating and pole piece coating system

Abstract

The utility model provides a magnetic assembly for pole piece coating, which comprises a first magnet, a second magnet, a first magnetic pole, a second magnetic pole, a second magnetic pole, a third magnetic pole, a third magnetic pole and a fourth magnetic pole, the second magnet is provided with a third magnetic pole and a fourth magnetic pole opposite to the third magnetic pole in magnetism, and the second magnet is provided with a second magnetic field direction; 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 can provide uniform magnetic field intensity to uniformly magnetize graphite particles in the pole piece, the included angle between the graphite particles is close to 180 degrees, the expansion of graphite in the charging and discharging process of the battery is reduced, the anisotropy of the graphite particles of the pole piece can be reduced through magnetization treatment, and the service life of the battery is prolonged. And the intensity ratio of I (004) / I (110) in the crystal lattice is increased, so that the diffusion internal resistance of the magnetized pole piece is reduced, and the rate and cycle performance of the battery are improved. The utility model further provides a pole piece coating system.

Description

Technical Field

[0001] The utility model relates to the technical field of secondary batteries, in particular to a magnetic component and a pole piece coating system for pole piece coating. Background Art

[0002] During the magnetization process of the coated graphite slurry, the magnetic field strength and uniformity of the permanent magnet will directly affect the magnetization effect on the graphite particles, which in turn affects the expansion direction of the battery core and causes the foil to rupture. Magnetization of graphite particles mainly involves placing the foil coated with graphite slurry under a permanent magnet. The graphite particles are subjected to a magnetic field of a certain strength, causing the graphite particles to deflect under the action of the magnetic field, and the angle after deflection is close to 180°.

[0003] There are many magnetizing devices for graphite particles, but most permanent magnet devices suffer from the problem of magnetic field unevenness. In the end, only a part of the graphite is magnetized, and some graphite particles will not be magnetized because the magnetic field strength or magnetic field uniformity does not meet the requirements. Ultimately, the non-magnetized areas will rupture due to vertical expansion.

[0004] In view of this, it is indeed necessary to provide a technical solution to the above problems. Utility Model Content

[0005] One of the purposes of the present invention is to address the deficiencies of the prior art and provide a magnetic component for pole piece coating, thereby improving the problem of uneven magnetization of graphite particles in the pole piece leading to expansion and rupture of the graphite particles during battery charging and discharging.

[0006] In order to achieve the above purpose, the utility model adopts the following technical solutions:

[0007] A magnetic component for pole piece coating, comprising:

[0008] A first magnet having a first magnetic pole and a second magnetic pole having a magnetic opposite direction to the first magnetic pole, wherein the first magnet has a first magnetic field direction;

[0009] The second magnet has a third magnetic pole and a fourth magnetic pole with magnetic properties opposite to the third magnetic pole, and the second magnet has a second magnetic field direction; wherein the first magnetic field direction is opposite to the second magnetic field direction.

[0010] 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.

[0011] Preferably, 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.

[0012] Preferably, the magnetic field strength of the first magnet is equal to the magnetic field strength of the second magnet.

[0013] Preferably, the magnetic field strength of the first magnet and the magnetic field strength of the second magnet are both 470-475 mT.

[0014] Preferably, the first magnet and the second magnet are arranged side by side.

[0015] Preferably, the first magnet and the second magnet are both permanent magnets.

[0016] Preferably, the first magnet and the second magnet have the same shape and size.

[0017] Preferably, the first magnet and the second magnet are in a shape of at least one of a cuboid, a cube, a cylinder, and a prism.

[0018] A second object of the present invention is to provide a pole piece coating system, comprising any of the magnetic components for pole piece coating described above.

[0019] Compared to the prior art, the present invention has the following advantages: the magnetic assembly for pole piece coating provided by the present invention comprises a first magnet and a second magnet, wherein the two magnets are of equal size and have opposite magnetic field directions. This magnetic assembly can provide a uniform magnetic field strength, causing the graphite particles in the pole piece to be uniformly magnetized, with the angle between the graphite particles approaching 180°, thereby reducing the expansion of the graphite during the battery's charge and discharge process. Furthermore, the magnetization treatment can reduce the anisotropy of the pole piece graphite particles and increase the I(004) / I(110) intensity ratio in the lattice, thereby reducing the diffusion internal resistance of the magnetized pole piece and improving the battery's rate and cycle performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 This is a schematic structural diagram of a magnetic assembly according to an embodiment of the present invention;

[0021] Figure 2 This is a diagram showing the magnetic field line distribution of a magnetic component according to an embodiment of the present invention.

[0022] Among them, 1 is the first magnet; 11 is the first magnetic pole; 12 is the second magnetic pole; 2 is the second magnet; 21 is the third magnetic pole; 22 is the fourth magnetic pole. DETAILED DESCRIPTION

[0023] In order to make the technical solutions and advantages of the present invention clearer, the present invention and its beneficial effects will be described in further detail below in conjunction with specific implementation methods and the accompanying drawings, but the implementation methods of the present invention are not limited thereto.

[0024] In the description of this utility model, unless otherwise expressly specified or limited, the terms "installed," "connected," "connected," and "fixed" should be understood in a broad sense. For example, they can refer to fixed connection, detachable connection, or integration; mechanical connection or electrical connection; direct connection or indirect connection through an intermediate medium; internal communication between two components or interaction between two components. Those skilled in the art will understand the specific meanings of the above terms in this utility model based on the specific circumstances.

[0025] The standard parts used in this utility model can all be purchased from the market, and special-shaped parts can be customized according to the description in the specification and the drawings. The specific connection methods of each part all adopt conventional means such as bolts, rivets, welding, etc. that are mature in the existing technology. The machinery, parts and equipment all adopt conventional models in the existing technology, and the circuit connection adopts the conventional connection method in the existing technology, which will not be described in detail here. The terms "first" and "second" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of such features. In the description of this utility model, the meaning of "multiple" is two or more, unless otherwise clearly and specifically defined.

[0026] like Figures 1-2 As shown, the first aspect of the utility model is to provide a magnetic component for pole piece coating, comprising: a first magnet 1, having a first magnetic pole 11 and a second magnetic pole 12 with opposite magnetic properties to the first magnetic pole 11, the first magnet 1 having a first magnetic field direction; a second magnet 2, having a third magnetic pole 21 and a fourth magnetic pole 22 with opposite magnetic properties to the third magnetic pole 21, the second magnet 2 having a second magnetic field direction; wherein the first magnetic field direction is opposite to the second magnetic field direction.

[0027] The pole piece magnetization process is a crucial step in lithium battery manufacturing. It involves treating magnetic materials through specific methods to align their internal magnetic domains, thereby exhibiting magnetism. During the preparation of lithium battery pole pieces, magnetization technology can be used to improve their performance.

[0028] At present, in the process of magnetizing graphite particles in the coating process, a single permanent magnet is often used for magnetization. If a single permanent magnet is used for magnetization, there will often be strong non-uniformity in the transverse direction of the permanent magnet. There will be some areas with high magnetic induction intensity, and some areas with low magnetic induction intensity. This will result in only a part of the graphite particles being magnetized and deflected in the transverse direction. The graphite particles in some areas will remain stationary and will not deflect because the magnetic induction intensity is too low. The dual permanent magnet parallel structure used in the utility model makes the magnetic induction intensity of the foil highly uniform, the magnetic induction intensity is better than that of a single permanent magnet, and the fluctuation of the magnetic induction intensity in the transverse direction of the permanent magnet is very small, and the magnetization efficiency is higher.

[0029] The first magnetic field is directed from the first magnetic pole 11 to the second magnetic pole 12; the second magnetic field is directed from the fourth magnetic pole 22 to the third magnetic pole 21. This means the first magnetic field is in the opposite direction to the second magnetic field, meaning the first magnet 1 and the second magnet 2 attract each other. Since the magnetic field lines start from the north pole of the magnet and return to the south pole, forming a closed magnetic field loop, their magnetic field lines connect to form a stronger magnetic field, thereby generating an attractive force.

[0030] In some embodiments, the first magnetic pole 11 is an S pole, the second magnetic pole 12 is an N pole; the third magnetic pole 21 is an N pole, and the fourth magnetic pole 22 is an S pole.

[0031] In some embodiments, the magnetic field strength of the first magnet 1 is equal to the magnetic field strength of the second magnet 2. Since the graphite in the pole piece is magnetized, the magnetic field strengths of the first magnet 1 and the second magnet 2 must be the same to ensure uniform magnetization of the graphite particles and maintain approximately the same deflection angle during magnetization.

[0032] In some embodiments, the magnetic field strength of the first magnet 1 and the magnetic field strength of the second magnet 2 are both 470-475 mT. Specifically, they can be 471 mT, 471.1 mT, 471.2 mT, 471.3 mT, 471.4 mT, 471.5 mT, 471.6 mT, 471.7 mT, 471.8 mT, 471.9 mT, 472 mT, 472.1 mT, 471.2 mT, 472.3 mT, 472.4 mT, 472.5 mT, 472.6 mT, 472.7 mT, 472.8 mT, 472.9 mT, 473 mT, 473.1 mT. , 473.2mT, 473.3mT, 473.4mT, 473.5mT, 473.6mT, 473.7mT, 473.8mT, 473.9mT, 474mT, 474.1mT, 474.2mT, 474.3mT, 474.4mT, 474.5mT, 474.6mT, 474.7mT, 474.8mT, 474.9mT, 475mT, may include but are not limited to the listed values, preferably 473.4mT.

[0033] In some embodiments, the first magnet 1 and the second magnet 2 are arranged side by side. Arranging the magnets side by side can effectively enhance the magnetic induction intensity, improve the uniformity of the magnetic field, better magnetize the graphite particles, and reduce the expansion of the graphite during the charging and discharging process.

[0034] In some embodiments, both the first magnet 1 and the second magnet 2 are permanent magnets. The permanent magnet material includes at least one of an aluminum-nickel-cobalt permanent magnet alloy, an iron-chromium-cobalt permanent magnet alloy, a barium ferrite, a strontium ferrite, a rare earth cobalt permanent magnet material, and a neodymium-iron-boron permanent magnet material. Permanent magnets maintain their magnetism over long periods of time and are not easily demagnetized by environmental interference. This long-term stable magnetism makes permanent magnets an ideal choice for many devices requiring a persistent magnetic field.

[0035] In some embodiments, the first magnet 1 and the second magnet 2 have the same shape and size. The same shape and size can ensure that the graphite particles to be magnetized are uniformly magnetized without uneven magnetization.

[0036] In some embodiments, the first magnet 1 and the second magnet 2 are in the shape of at least one of a cuboid, a cube, a cylinder, and a prism, preferably a cuboid.

[0037] The size and shape of the magnet in the present invention can be adjusted according to the size of the pole piece to be magnetized in the wound battery core.

[0038] According to a second aspect of the present invention, the present invention further provides a pole piece coating system, comprising a coating device and any one of the above-mentioned magnetic components for pole piece coating.

[0039] The coating device 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, and a back roller. The magnetic component is set in the latter process of the coating device to magnetize the pole piece after coating.

[0040] The coated pole piece is placed beneath the magnetic assembly, completely covered by the magnetic field. Under the influence of the magnetic field, the graphite particles in the pole piece align according to the direction of the magnetic field. In this utility model, the graphite particles are oriented at an angle of approximately 180°. The magnetized pole piece is then placed in a dryer for drying. During the drying process, the solvent evaporates, leaving behind a solidified conductive paste. During the drying process, the heat stabilizes the relative positions of the magnetized graphite particles, ensuring the stability and consistency of the pole piece.

[0041] The entire system needs to be designed to ensure that the coating device and the magnetic assembly work together so that the pole pieces can be dried immediately after magnetization to avoid adverse effects of the magnetic field on the uncured pole pieces.

[0042] Unless otherwise specified, the raw materials adopted in the present invention can be purchased from the market or are commonly used in this area. Unless otherwise specified, the methods in the following embodiments are all conventional methods in this area. According to the disclosure and teachings of the above description, those skilled in the art in the field to which the present invention belongs can also change and modify the above embodiment. Therefore, the present invention is not limited to the above-mentioned specific embodiments, and any obvious improvement, replacement or modification made by those skilled in the art on the basis of the present invention all fall within the scope of protection of the present invention. In addition, although some specific terms are used in this specification, these terms are only for convenience of description and do not constitute any restriction to the present invention.

Claims

1. A magnetic component for pole piece coating, characterized in that: include: A first magnet having a first magnetic pole and a second magnetic pole having a magnetic opposite direction to the first magnetic pole, wherein the first magnet has a first magnetic field direction; a second magnet having a third magnetic pole and a fourth magnetic pole magnetically opposite to the third magnetic pole, wherein the second magnet has a second magnetic field direction; The direction of the first magnetic field is opposite to the direction of the second magnetic field.

2. The magnetic component for pole piece coating according to claim 1, characterized in that: 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.

3. The magnetic component for pole piece coating according to claim 1 or 2, characterized in that: 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 component for pole piece coating according to claim 1, characterized in that: The magnetic field strength of the first magnet is equal to the magnetic field strength of the second magnet.

5. The magnetic component for pole piece coating according to claim 4, characterized in that: The magnetic field strength of the first magnet and the magnetic field strength of the second magnet are both 470-475 mT.

6. The magnetic component for pole piece coating according to claim 1, characterized in that: The first magnet and the second magnet are arranged side by side.

7. The magnetic component for pole piece coating according to claim 1, characterized in that: The first magnet and the second magnet are both permanent magnets.

8. The magnetic component for pole piece coating according to claim 1, characterized in that: The first magnet and the second magnet have the same shape and size.

9. The magnetic component for pole piece coating according to claim 1, characterized in that: The first magnet and the second magnet are in a shape of at least one of a cuboid, a cube, a cylinder, and a prism.

10. A pole piece coating system, characterized by: The invention comprises a magnetic component for pole piece coating according to any one of claims 1 to 9.

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