Graphite cathode material screening and demagnetizing device

Abstract

The invention belongs to the technical field of battery negative electrode material processing, and particularly relates to a graphite negative electrode material screening and demagnetizing device. The device comprises a conveying box, a conveying channel and demagnetizing equipment, and the demagnetizing equipment comprises a demagnetizing box arranged at the side end of the conveying box, a channel arranged on the side wall of the conveying box, a driving structure arranged on the demagnetizing box and an electromagnetic rod which is connected with the driving structure and enters / leaves the conveying box through the channel. And the control structure is used for supplying power to the electromagnetic rod. Through the arrangement of the conveying box, the conveying channel and the magnetism removing equipment, magnetic substances in conveyed raw materials can be rapidly adsorbed, the adsorbed magnetic substances can be taken away from the conveying position along with work of the magnetism removing equipment and removed, and the risk that the magnetic substances fall into the raw materials is avoided; therefore, the requirement on the precision of the magnetic intensity of the demagnetizing equipment is not high, and the method is easy to implement and has the advantages of high practicability and simplicity and convenience in operation.

Description

Technical Field

[0001] The invention belongs to the technical field of battery negative electrode material processing, and in particular relates to a graphite negative electrode material screening and demagnetization device. Background Art

[0002] As negative electrode material, artificial graphite is an ideal choice for negative electrode materials of lithium-ion batteries due to its advantages of high energy density, high power density and low cost. The main graphite particles of high-capacity and high-retention composite graphite materials for energy storage are artificial graphite obtained by crushing, shaping, granulating and high-temperature graphitization of needle coke and petroleum coke; its general preparation process includes mixing various raw materials in proportion, adding adhesives for coating, bonding and high-temperature carbonization to obtain carbonized products, and then crushing, screening, mixing and demagnetizing the carbonized products to produce high-capacity and high-retention composite graphite materials with uniform physical and chemical properties.

[0003] Among them, demagnetization is generally done by electric demagnetization, and the magnetic material is adsorbed and removed by the magnetic field generated by electricity. The existing demagnetization device generally sets an electric plate on the top side of the conveyor belt to adsorb and remove the magnetic material during transportation. However, the existing device is fixed, and after adsorbing a certain amount of impurities, its adsorption capacity will be affected, resulting in the inability to completely remove the magnetic impurities, thereby affecting the quality of the finished graphite.

[0004] The document with application publication number CN117181444A discloses a graphite negative electrode material demagnetization device, including a support rod, a demagnetization box and an energized conductive rod, wherein the energized conductive rod is arranged inside the demagnetization box, and a feed plate and a discharge support plate are respectively arranged at both ends of the demagnetization box, a vibrating mechanism is arranged between the feed plate and the discharge support plate, a demagnetization mechanism is arranged on the outer side of the energized conductive rod, and a linkage mechanism is arranged between the energized conductive rod and the vibrating mechanism to drive the two to move synchronously.

[0005] The working principle of the device is: through the rotation of the energized conductive rod, the graphite in the transportation process is adsorbed, and all surfaces of the energized conductive rod can be adsorbed, replacing the traditional fixed energized plate, ensuring that the energized conductive rod removes the impurities adsorbed on the surface through the removal mechanism after adsorbing a certain amount of impurities, ensuring that the adsorption capacity of the energized conductive rod will not be affected, and the reciprocating screw rod of the removal mechanism can control the reciprocating movement of the scraper to scrape the surface of the energized conductive rod to ensure the adsorption efficiency of the energized conductive rod.

[0006] However, the device still has the following problems: the magnetic strength of the energized conductive rod cannot be controlled. In order to adsorb the material, the magnetic strength needs to be strong enough, but this will also increase the difficulty of the scraper structure to scrape off the adsorbed magnetic material, and the magnetic material that falls off after scraping is also easy to fall back onto the transmitted raw material, resulting in an unsatisfactory removal rate of the magnetic material. Summary of the invention

[0007] In view of the above-mentioned problems, the present invention provides a graphite negative electrode material screening and demagnetization device, which can quickly adsorb magnetic substances in the raw materials being transmitted through the arrangement of a transmission box, a transmission channel and a demagnetization device, and the adsorbed magnetic substances will be taken away from the transmission position and removed as the demagnetization device works, and there is no risk of the magnetic substances falling into the raw materials. Therefore, the accuracy requirements for the magnetic strength of the demagnetization device are not high, and it is easy to implement, with the advantages of strong practicality and simple operation.

[0008] In order to achieve the above object, the technical solution of the present invention is as follows: A graphite negative electrode material screening and demagnetization device comprises a transmission box, a transmission channel arranged in the transmission box, and a demagnetization device, wherein the demagnetization device comprises a demagnetization box arranged on the side end of the transmission box, a channel arranged on the side wall of the transmission box, a driving structure arranged on the demagnetization box, an electromagnetic rod connected to the driving structure and entering / leaving the transmission box through the channel, and a control structure for supplying power to the electromagnetic rod.

[0009] As a further preferred embodiment of the present invention, the electromagnetic rod performs a circular motion, and the electromagnetic rod rotates through the upper end of the transmission channel.

[0010] As a further preferred embodiment of the present invention, the electromagnetic rod includes a rod body and a protective cover arranged outside the rod body; the control structure includes a wire wound around the outer circumference of the rod body and a power source connected to the wire.

[0011] As a further preferred embodiment of the present invention, the conducting wire comprises a first connecting segment and a second connecting segment connected to two electrodes of the power supply, and two main segments connected to the rod body; one of the main segments is connected to the first connecting segment, the other main segment is connected to a first conductive sheet, and the end of the second connecting segment away from the power supply is connected to a second conductive sheet; the protective cover comprises an inner cylinder on which the first conductive sheet is installed, and an outer cylinder on which the second conductive sheet is installed and slidably connected to the inner cylinder; the control structure also comprises a control member for controlling the relative position of the inner cylinder and the outer cylinder.

[0012] As a further preferred embodiment of the present invention, the control member includes a support spring arranged on the end of the electromagnetic rod close to the inner cylinder / outer cylinder and connected to the inner wall of the inner cylinder / outer cylinder, and an extrusion plate arranged on the inner wall of the demagnetizing box and used to squeeze the inner cylinder / outer cylinder.

[0013] As a further preferred embodiment of the present invention, the protective cover also includes a track arranged on the inner wall of the outer cylinder, and a sliding column arranged on the outer wall of the inner cylinder and inserted into the track; the second conductive sheet is installed on the bottom surface of the track, the sliding column is connected to the first conductive sheet, and the sliding column is a conductive material.

[0014] As a further preferred embodiment of the present invention, the protective cover is provided with a circuit channel through which the first connecting section and the second connecting section pass.

[0015] As a further preferred embodiment of the present invention, the magnetic removal box includes a box body, a flat plate arranged in the box body and docked with the channel, a magnetic removal port arranged at the lower end of the box body, and a guiding slope arranged on the inner wall of the box body and extending to the magnetic removal port.

[0016] As a further preferred embodiment of the present invention, the driving structure includes a fixed cylinder arranged on the flat plate, a rotating shaft rotatably arranged in the fixed cylinder, a fixed block arranged on the rotating shaft and used to install the electromagnetic rod, and a motor arranged on the demagnetization box and having an output shaft passing through the demagnetization box and connected to the rotating shaft.

[0017] The present invention also provides a method for controlling the above-mentioned graphite negative electrode material screening and demagnetization device, comprising: when the electromagnetic rod enters the demagnetization box, the control component drives the inner cylinder / outer cylinder to slide so that the first conductive sheet and the second conductive sheet are misaligned, the main section is powered off, and the magnetism of the electromagnetic rod disappears or weakens; when the electromagnetic rod leaves the demagnetization box, the control component drives the inner cylinder / outer cylinder to slide so that the first conductive sheet and the second conductive sheet are docked, the main section is powered on, and the magnetism of the electromagnetic rod is restored or strengthened.

[0018] The beneficial effects of the present invention are as follows: The demagnetization device provided by the present invention can quickly adsorb magnetic substances in raw materials being transmitted through the setting of a transmission box, a transmission channel, and a demagnetization device, and the adsorbed magnetic substances will be taken away from the transmission position and removed as the demagnetization device works. There is no risk of magnetic substances falling into the raw materials. Therefore, the accuracy requirements for the magnetic strength of the demagnetization device are not high, it is easy to implement, and has the advantages of strong practicality and simple operation.

[0019] In the demagnetization device provided by the present invention, the power supply state of the electromagnetic rod is switched according to the position of the electromagnetic rod, and the functions of sucking and unloading materials are finally realized. The device has clear indicators, simple control, strong economy and easy maintenance. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Attached Figure 1 It is a schematic diagram of the structure of the present invention from a top view.

[0021] Attached Figure 2 It is a schematic diagram of the internal structure of the present invention from a top view.

[0022] Attached Figure 3 It is a structural schematic diagram of the electromagnetic rod of the present invention.

[0023] Attached Figure 4 The figure is a schematic diagram of the internal structure of the demagnetization box of the present invention at the main viewing angle.

[0024] Attached Figure 5 Schematic diagram of the circuit of the electromagnetic rod of the present invention.

[0025] Attached Figure 6 It is a schematic diagram of the partial structure of the electromagnetic rod and the control structure of the present invention from a top view.

[0026] Attached Figure 7 It is a schematic diagram of the local structure of the connection between the inner cylinder and the outer cylinder in a top view of the present invention.

[0027] Description of the drawings: bracket a, buffer support b, transmission box 1, transmission channel 2, demagnetization equipment 3; Horizontal box 11, feed port 12, discharge port 13; Conveying belt 21, conveying roller body 22, conveying motor 23, baffle 24; In addition to the magnetic box 31, the channel 32, the driving structure 33, the electromagnetic rod 34, and the control structure 35; Box body 311, flat plate 312, magnetic discharge port 313, guiding slope 314; A fixed cylinder 331, a rotating shaft 332, a fixed block 333, and a motor 334; Rod body 341, protective cover 342; Inner cylinder 342a, outer cylinder 342b, track 342c, sliding column 342d, circuit channel 342e; Wire 351, power supply 352, control element 353; A first connecting section 351a, a second connecting section 351b, a main section 351c, a first conductive sheet 351d, and a second conductive sheet 351e; Support spring 353a and pressing plate 353b. DETAILED DESCRIPTION

[0028] In the description of the present invention, it should be understood that the terms "upper", "lower", "inside", "outside", "left", "right", etc. indicate directions or positional relationships based on the directions or positional relationships shown in the accompanying drawings, or are directions or positional relationships in which the product of the invention is usually placed when in use, or are directions or positional relationships commonly understood by those skilled in the art. These directions or positional relationships are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore should not be understood as a limitation on the present invention.

[0029] In the description of the present invention, it is also necessary to explain that, unless otherwise clearly specified and limited, the terms such as "setting" and "connection" should be understood in a broad sense. For example, "connection" can be a fixed connection, a detachable connection, or an integral connection: it can be a mechanical connection or an electrical connection: it can be a direct connection, or it can be an indirect connection through an intermediate medium, or it can be the internal communication of two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0030] Example 1 The present invention provides a graphite negative electrode material screening and demagnetization device, comprising a transmission box 1, a transmission channel 2 arranged in the transmission box 1, and a demagnetization device 3.

[0031] In this embodiment, the transmission box 1 includes a horizontal box body 11, a feeding port 12 is provided on one side of the upper end of the horizontal box body 11, and a discharging port 13 is provided on the side away from the horizontal box body 11. The horizontal box body 11 is installed on a bracket a, and a buffer support b connected to the four corners of the horizontal box body 11 is also provided on the bracket a, and the buffer support b can be a buffer spring.

[0032] In this embodiment, the transmission channel 2 includes a transmission belt 21, a transmission roller body 22, and a transmission motor 23; wherein, the transmission belt 21 is installed on at least two transmission roller bodies 22 rotatably installed in the horizontal box body 11, and the transmission motor 23 is used to drive the transmission roller body 22 to rotate. The transmission belt 21 is moved by the synchronous rotation of the transmission roller body 22, thereby driving the material on the transmission belt to move from the feed port 12 to the discharge port 13.

[0033] It is understandable that in order to improve the demagnetization efficiency, the material on the conveyor belt 21 needs to be spread out as much as possible. Therefore, a vibration motor (not shown in the figure) for driving the conveyor belt 21 to vibrate can also be installed in the horizontal box 11; in order to prevent the material from falling from the conveyor belt 21, baffles 24 protruding from the upper surface of the conveyor belt 21 are provided on the two side ends of the conveyor belt 21.

[0034] In this embodiment, the demagnetization device 3 includes a demagnetization box 31 arranged on the side end of the transmission box 1, a channel 32 arranged on the side wall of the transmission box 1, a driving structure 33 arranged on the demagnetization box 31, an electromagnetic rod 34 connected to the driving structure 33 and entering / leaving the transmission box 1 through the channel 32, and a control structure 35 for supplying power to the electromagnetic rod 34.

[0035] Among them, the demagnetization box 31 is arranged in the middle of the transmission box 1 or near the discharge port 13. The channel 32 is arranged on the side wall of the transmission box 1 parallel to the transmission channel 2. The length of the channel 32 matches the length of the internal space of the demagnetization box 31, and the width of the channel 32 needs to ensure that the electromagnetic rod 34 can pass through. The driving structure 33 is used to control the movement of the electromagnetic rod 34. The driving structure 33 can be a power device that drives the electromagnetic rod 34 to translate. At this time, the electromagnetic rod 34 is preferably parallel to the length direction of the channel 32 to ensure that the effective adsorption area is increased as much as possible and the demagnetization efficiency is improved when the path from entering the transmission box 1 to leaving the transmission box 1 remains unchanged; the driving structure 33 can also be a power device that drives the electromagnetic rod 34 to rotate. At this time, the electromagnetic rod 34 makes a circular motion. When the electromagnetic rod 34 rotates through the upper end of the transmission channel 2, compared with the translation method, its effective adsorption area is larger, so this embodiment is preferred.

[0036] As a preferred embodiment of the present invention, the demagnetization box 31 includes a box body 311, a flat plate 312 disposed in the box body 311 and docked with the channel 32, a magnetic discharge port 313 disposed at the lower end of the box body 311, and a guide slope 314 disposed on the inner side wall of the box body 311 and extending to the magnetic discharge port 313. The flat plate 312 is a strip-shaped plate, which docks with the channel 32 to provide a platform for the installation of the drive structure 33 and the electromagnetic rod 34; the magnetic discharge port 313 is used to discharge the fallen magnetic material, and a valve body (not marked in the figure) of the control switch can be installed on it; the guide slope 314 is mainly used to quickly guide the magnetic material to the magnetic discharge port 313 to increase the discharge speed.

[0037] As a preferred embodiment of this embodiment, the driving structure 33 includes a fixed cylinder 331 arranged on the flat plate 312, a rotating shaft 332 rotatably arranged in the fixed cylinder 331, a fixed block 333 arranged on the rotating shaft 332 and used to install the electromagnetic rod 34, and a motor 334 arranged on the demagnetization box 31 and having an output shaft passing through the demagnetization box 31 and connected to the rotating shaft 332. Among them, a bearing is arranged between the rotating shaft 332 and the demagnetization box 31, and the fixed block 333 is a block fixedly installed on the rotating shaft 332. A plurality of fixed blocks 333 can be arranged and vertically distributed on the rotating shaft 332. One fixed block 333 corresponds to one electromagnetic rod 34. By increasing the number of electromagnetic rods 34, the frequency of the electromagnetic rods 34 entering the transmission box 1 can be increased, thereby improving the demagnetization efficiency.

[0038] In this embodiment, the electromagnetic rod 34 includes a rod body 341 and a protective cover 342 arranged on the outside of the rod body 341; the control structure 35 includes a wire 351 wound around the outer peripheral side of the rod body 341 and a power supply 352 connected to the wire 351, and the power supply 352 has a switch for turning on / off the power supply, which can be manually controlled or connected to a control panel and controlled by the control panel. Among them, the protective cover 342 is made of insulating material, which is used to protect the rod body 341 and avoid the safety hazard of leakage; the rod body 341 can be an electromagnetic rod, which is connected to the two poles of the power supply 352 through two wires 351 respectively. When the rod body 341 is energized, it generates electromagnetic attraction, so that it has the ability to absorb magnetic substances in the raw materials.

[0039] The working principle of the screening and demagnetization device provided in this embodiment is as follows: the raw material to be demagnetized is input into the horizontal box 11 through the feed port 12, the raw material falls onto the transmission channel 2 and moves toward the discharge port 13, the driving structure 33 is started, and the electromagnetic rod 34 repeatedly enters the horizontal box 11 through the channel 32 and passes over the transmission channel 2. The control structure 35 is started and stopped according to the position of the electromagnetic rod 34. When the electromagnetic rod 34 is located in the horizontal box 11, the control structure 35 is turned on, the electromagnetic rod 34 is energized to generate electromagnetic attraction, and the magnetic material is attracted by the electromagnetic rod 34 and moves with the electromagnetic rod 34; when the electromagnetic rod 34 enters the demagnetization box 31, the control structure 35 is turned off, the electromagnetic rod 34 is deenergized, and the electromagnetic attraction disappears. At this time, the magnetic material brought into the demagnetization box 31 falls into the demagnetization box 31 under the action of gravity.

[0040] Example 2 This embodiment is optimized on the basis of the embodiment 1, aiming to improve the automation degree of power on / off of the electromagnetic rod 34, and the specific structure is as follows: In this embodiment, the conductive wire 351 includes a first connecting segment 351a and a second connecting segment 351b connected to two electrodes of the power source 352, and two main segments 351c connected to the rod body 341; one of the main segments 351c is connected to the first connecting segment 351a, the other main segment 351c is connected to a first conductive sheet 351d, and the end of the second connecting segment 351b away from the power source 352 is connected to a second conductive sheet 351e.

[0041] The two main body segments 351c can be two wires connected to the rod body 341, or two interfaces of a wire wound around the rod body 341. The former is used to directly control the electrification of the rod body 341, and the latter is used to form a coil outside the rod body 341. The electrification of the coil generates a magnetic field in the same direction as the rod body 341, which is used to enhance the magnetic field strength and improve the magnetic attraction. When the first conductive sheet 351d and the second conductive sheet 351e are connected, an electrified path is formed, thereby forming a magnetic field; when the first conductive sheet 351d and the second conductive sheet 351e are misaligned, the path is disconnected, and the magnetic field disappears or weakens.

[0042] Specifically, the protective sleeve 342 includes an inner cylinder 342a equipped with the first conductive sheet 351d, and an outer cylinder 342b equipped with the second conductive sheet 351e and slidably connected to the inner cylinder 342a; the control structure 35 also includes a control member 353 for controlling the relative position of the inner cylinder 342a and the outer cylinder 342b. Among them, the inner cylinder 342a and the outer cylinder 342b are both closed at one end and open at the other end, and the two openings are butted together. The rod body 341 is installed in the outer cylinder 342b, and after the rod body 341 is installed, there is a gap between the rod body 341 and the outer cylinder 342b for the outer wall of the inner cylinder 342a to be inserted, so as to ensure the close connection between the inner cylinder 342a and the outer cylinder 342b, thereby ensuring that the first conductive sheet 351d and the second conductive sheet 351e can fit closely and conduct electricity successfully; the position of the inner cylinder 342a in the outer cylinder 342b is controlled by the control member 353, so that the first conductive sheet 351d and the second conductive sheet 351e can be butted together or misaligned, and the power on and off of the path can be controlled. Furthermore, when the protective sleeve 342 is at its maximum length, the first conductive sheet 351d and the second conductive sheet 351e are butted together.

[0043] In this embodiment, the control member 353 includes a support spring 353a arranged on the end of the electromagnetic rod 34 close to the inner cylinder 342a / outer cylinder 342b and connected to the inner wall of the inner cylinder 342a / outer cylinder 342b, and an extrusion plate 353b arranged on the inner wall of the demagnetization box 31 and used to squeeze the inner cylinder 342a / outer cylinder 342b.

[0044] It is worth noting that both the inner cylinder 342a and the outer cylinder 342b can be arranged at the end near the side wall of the demagnetization box 31, and the bottom surface of the cylinder located on the outside is used to install the support spring 353a; the extrusion plate 353b can be a plate protruding from the side wall of the demagnetization box 31, or the inner wall body of the demagnetization box 31 has a shape so that the electromagnetic rod 34 is compressed during the rotation process. More preferably, the two symmetrically distributed inner walls of the demagnetization box 31 near the channel 32 have an introduction section, and the two ends of the inner wall away from the channel 32 are respectively connected to the introduction section as the main compression section, so that the electromagnetic rod 34 can be powered off after rotating to a certain distance from the demagnetization box 31, so that the magnetic material can fall in the middle of the box body, which is convenient for collection and discharge, and the extension and contraction of the electromagnetic rod 34 can be gradual, which is convenient for improving the service life.

[0045] As a further preferred embodiment of the present invention, the protective sleeve 342 further comprises a track 342c arranged on the inner wall of the outer cylinder 342b, a sliding post 342d arranged on the outer wall of the inner cylinder 342a and inserted into the track 342c; the second conductive sheet 351e is mounted on the bottom surface of the track 342c, the sliding post 342d is connected to the first conductive sheet 351d, and the sliding post 342d is a conductive material. The sliding connection between the track 342c and the sliding post 342d can enhance the stability of the sliding connection between the inner cylinder 342a and the outer cylinder 342b, the conductive material selected by the sliding post 342d can be any metal material, preferably the same as the material of the first conductive sheet 351d, and preferably, the sliding post 342d is fixedly connected or integrally formed with the first conductive sheet 351d. When there is only one sliding column 342d, it is preferably installed on the lower surface of the inner cylinder 342a, so that the gravity of the inner cylinder 342a can be used to ensure that the sliding column 342d can be tightly pressed against the bottom surface of the track 342c; in order to ensure the stability of sliding, a sliding column should also be provided on the other side of the sliding column 342d. The column can be made of insulating material, and the first conductive sheet does not need to be set, and it only plays the function of strengthening the sliding connection.

[0046] As a further preference of this embodiment, the protective cover 342 is provided with a circuit channel 342e through which the first connecting segment 351a and the second connecting segment 351b pass. The circuit channel 342e is preferably parallel to the side wall of the cylinder to avoid the accidental breakage of the passage due to squeezing the first connecting segment and the second connecting segment during extension and retraction.

[0047] The present embodiment provides a method for controlling the above-mentioned graphite negative electrode material screening and demagnetization device, comprising: when the electromagnetic rod 34 enters the demagnetization box 31, the control component 353 drives the inner cylinder 342a / outer cylinder 342b to slide so that the first conductive sheet 351d and the second conductive sheet 351e are misaligned, the main body section 351c is powered off, and the magnetism of the electromagnetic rod 34 disappears or weakens; when the electromagnetic rod 34 leaves the demagnetization box 31, the control component 353 drives the inner cylinder 342a / outer cylinder 342b to slide so that the first conductive sheet 351d and the second conductive sheet 351e are docked, the main body section 351c is powered on, and the magnetism of the electromagnetic rod 34 is restored or strengthened.

[0048] The specific embodiments described herein are merely examples of the spirit of the present invention. Those skilled in the art may make various modifications or additions to the specific embodiments described or replace them in similar ways, but they will not deviate from the spirit of the present invention or exceed the scope defined by the appended claims.

Claims

1. A graphite negative electrode material screening and demagnetization device, comprising a transmission box (1), a transmission channel (2) arranged in the transmission box (1) and a demagnetization device (3), characterized in that: The demagnetization device (3) comprises a demagnetization box (31) arranged on the side end of the transmission box (1), a channel (32) arranged on the side wall of the transmission box (1), a driving structure (33) arranged on the demagnetization box (31), an electromagnetic rod (34) connected to the driving structure (33) and entering / leaving the transmission box (1) through the channel (32), and a control structure (35) for supplying power to the electromagnetic rod (34).

2. A graphite negative electrode material screening and demagnetization device according to claim 1, characterized in that: The electromagnetic rod (34) performs circular motion, and the electromagnetic rod (34) rotates through the upper end of the transmission channel (2).

3. A graphite negative electrode material screening and demagnetization device according to claim 2, characterized in that: The electromagnetic rod (34) comprises a rod body (341) and a protective cover (342) arranged outside the rod body (341); the control structure (35) comprises a wire (351) wound around the outer circumference of the rod body (341) and a power source (352) used to be connected to the wire (351).

4. A graphite negative electrode material screening and demagnetization device according to claim 3, characterized in that: The lead (351) comprises a first connection section (351a) and a second connection section (351b) connected to two electrodes of the power source (352), and two main sections (351c) connected to the rod body (341); one of the main sections (351c) is connected to the first connection section (351a), the other of the main sections (351c) is connected to a first conductive sheet (351d), and the end of the second connection section (351b) away from the power source (352) is connected to a second conductive sheet (351e); the protective sleeve (342) comprises an inner cylinder (342a) on which the first conductive sheet (351d) is mounted, and an outer cylinder (342b) on which the second conductive sheet (351e) is mounted and which is slidably connected to the inner cylinder (342a); and the control structure (35) further comprises a control member (353) for controlling the relative position of the inner cylinder (342a) and the outer cylinder (342b).

5. A graphite negative electrode material screening and demagnetization device according to claim 4, characterized in that: The control member (353) includes a support spring (353a) arranged on the end of the electromagnetic rod (34) close to the inner cylinder (342a) / outer cylinder (342b) and connected to the inner wall of the inner cylinder (342a) / outer cylinder (342b), and an extrusion plate (353b) arranged on the inner wall of the demagnetizing box (31) and used to squeeze the inner cylinder (342a) / outer cylinder (342b).

6. A graphite negative electrode material screening and demagnetization device according to claim 4, characterized in that: The protective sleeve (342) further comprises a track (342c) arranged on the inner wall of the outer tube (342b), and a sliding column (342d) arranged on the outer wall of the inner tube (342a) and inserted into the track (342c); the second conductive sheet (351e) is mounted on the bottom surface of the track (342c), the sliding column (342d) is connected to the first conductive sheet (351d), and the sliding column (342d) is a conductive material.

7. A graphite negative electrode material screening and demagnetization device according to claim 4, characterized in that: The protective sleeve (342) is provided with a circuit channel (342e) through which the first connecting section (351a) and the second connecting section (351b) pass.

8. The device for screening and demagnetizing graphite negative electrode materials according to claim 1, characterized in that: The magnetic removal box (31) comprises a box body (311), a flat plate (312) arranged in the box body (311) and connected to the channel (32), a magnetic removal opening (313) arranged at the lower end of the box body (311), and a guiding inclined surface (314) arranged on the inner side wall of the box body (311) and extending to the magnetic removal opening (313).

9. A graphite negative electrode material screening and demagnetization device according to claim 8, characterized in that: The driving structure (33) comprises a fixed cylinder (331) arranged on the flat plate (312), a rotating shaft (332) rotatably arranged in the fixed cylinder (331), a fixed block (333) arranged on the rotating shaft (332) and used for mounting the electromagnetic rod (34), and a motor (334) arranged on the demagnetization box (31) and having an output shaft passing through the demagnetization box (31) and connected to the rotating shaft (332).

10. A method for controlling a graphite negative electrode material screening and demagnetization device according to claim 4, characterized in that: include: When the electromagnetic rod (34) enters the demagnetizing box (31), the control component (353) drives the inner cylinder (342a) / outer cylinder (342b) to slide so that the first conductive sheet (351d) and the second conductive sheet (351e) are misaligned, the main body section (351c) is powered off, and the magnetism of the electromagnetic rod (34) disappears or weakens; when the electromagnetic rod (34) leaves the demagnetizing box (31), the control component (353) drives the inner cylinder (342a) / outer cylinder (342b) to slide so that the first conductive sheet (351d) and the second conductive sheet (351e) are docked, the main body section (351c) is powered on, and the magnetism of the electromagnetic rod (34) is restored or strengthened.

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