Device for intercepting fiber foreign matters in lithium battery graphite powder

Abstract

The invention relates to the technical field of lithium battery manufacturing, and particularly discloses a device for intercepting fiber foreign matters in lithium battery graphite powder. Comprising a shell, rolling brushes, a rotating disc and a driving device, a feeding pipe is arranged at the top of the shell, a discharging pipe is arranged at the bottom of the shell, the driving device is installed in the shell, the rolling brushes are rotationally installed on the rotating disc, roller shafts of the rolling brushes penetrate through the rotating disc and are fixedly provided with planetary gears, and the planetary gears are in meshing transmission connection with a fixed gear ring; the rolling brush rotates to make contact with graphite powder, fiber foreign matter in the graphite powder is intercepted in the mode that the fiber foreign matter and bristles are wound, and the filtering efficiency is high compared with the mode that a vibrating screen is adopted in the prior art; and the rolling brush rotates while rotating around the turntable, so that the bristles can be in contact with the falling graphite powder for many times, and the rejection rate of fiber foreign matters in the graphite powder is increased.

Description

Technical Field

[0001] The invention relates to the technical field of lithium battery manufacturing, and in particular to a device for intercepting fiber foreign matter in graphite powder of lithium batteries. Background Art

[0002] The negative electrode of a lithium battery is usually made of a mixture of graphite, conductive agents, adhesives and other additives, which are evenly coated on a current collector (metal foil). When the battery is charged, the lithium compounds in the positive electrode ionize lithium ions and enter the carbon layer of the negative electrode, thereby achieving the purpose of storing energy.

[0003] In the actual production process, the negative electrode powder coated with the negative electrode will produce bumps or depressions due to the presence of fibrous foreign matter mixed therein. The sources of fibrous foreign matter are relatively complex and diverse, and wear and tear of personnel's clothing and hair are collectively referred to as fibrous foreign matter. Judging from the production process, this is mainly due to the fact that the raw graphite materials are mostly packaged in ton bags or with bags for transportation. During the feeding process, the fibers in the packaging bags are broken and mixed into the graphite raw materials. Some of the fine fibers are difficult to be screened out. When the negative electrode material is coated by the coating machine, the fibers occupy the position of the negative electrode powder. If the fibers are coated in the negative electrode powder layer, bulges will occur. If the fibers are relatively thick, they may peel off and form depressions. The defects in the negative electrode powder layer on the negative electrode will cause the lithium ion embedding of the manufactured battery to be hindered during the charge and discharge process, making it easier for lithium ions to produce metallic lithium at the defective negative electrode position, that is, lithium plating. When the lithium plating phenomenon develops seriously, the dendrites of lithium metal may pierce the diaphragm, causing a short circuit between the positive and negative electrodes, causing the lithium battery to catch fire and explode.

[0004] Therefore, it is very important to ensure that the negative electrode powder coated with the negative electrode is uniform and to control the residual amount of fiber foreign matter brought into the graphite raw material. In the prior art, a multi-stage vibrating screen is usually used to separate the fiber foreign matter in the graphite raw material, but the screen of the vibrating screen is too fine and the screening efficiency is low, which affects the production efficiency. If the screen is too large, the fiber foreign matter with a shorter length will also be screened off the screen under the action of long-term vibration, resulting in the residual fiber foreign matter in the graphite raw material being difficult to be effectively intercepted and screened out. Summary of the invention

[0005] The purpose of the present invention is to provide a device for intercepting fiber foreign matter in lithium battery graphite powder to solve the problems existing in the prior art.

[0006] The present invention is implemented by the following technical scheme: a device for intercepting fibrous foreign matter in lithium battery graphite powder, comprising a shell, a roller brush, a turntable and a driving device, a feed pipe is provided at the top of the shell, a discharge pipe is provided at the bottom of the shell, a driving device is installed in the shell, the driving device comprises a fixed ring gear, a planetary gear, a driving shaft, a reducer and a driving motor, a fixed ring gear is fixedly installed in the shell, the driving shaft passes through the shell and is coaxially arranged with the fixed ring gear, one end of the driving shaft is transmission-connected with the output shaft of the reducer, the other end of the driving shaft is fixedly connected with the turntable, the input shaft of the reducer is transmission-connected with the output shaft of the driving motor, the reducer is fixedly installed on the outside of the shell, a plurality of roller brushes are rotatably installed on the turntable, the roller shaft of the roller brush passes through the turntable and is fixedly installed with a planetary gear, and the planetary gear is meshingly transmission-connected with the fixed ring gear.

[0007] Furthermore, the roller brush includes a brush roller, a roller shaft and bristles. The brush roller is a hollow cylinder. The roller shaft is coaxially fixed on the brush roller. The roller shaft is rotatably connected to the turntable through a bearing seat. Several rows of bristles are circumferentially arranged on the outer wall of the brush roller.

[0008] Furthermore, a keyway is provided in the brush roller, a key tooth engaged with the keyway is integrally formed on the roller shaft, a shaft ring is integrally formed on the roller shaft, one end of the brush roller abuts against the shaft ring, the other end of the brush roller abuts against a fixing screw, and the fixing screw is threadedly connected to the roller shaft.

[0009] Furthermore, the distance between the ends of the bristles of two adjacent roller brushes is 5-10 mm.

[0010] Furthermore, each cluster of bristles includes 20-50 stainless steel wires, and the diameter of the stainless steel wires is 0.2-0.4 mm.

[0011] Furthermore, the length of the bristles exposed from the brush roller is 0.5-0.8 times the diameter of the brush roller.

[0012] Furthermore, it also includes a negative pressure cleaning device, which includes an air intake pipe and a fixed roller brush. The driving shaft of the driving device is a hollow structure, and an air intake pipe is coaxially penetrated in the driving shaft. The air intake pipe is placed on the outside of the outer shell at one end and is connected to the high-pressure air source. The air intake pipe is placed inside the outer shell at one end and passes through the driving shaft and the turntable and is fixedly connected to the fixed roller brush. Bristles are installed on the fixed roller brush. The fixed roller brush is a hollow structure. The hollow inner cavity of the fixed roller brush is connected to the air intake pipe, and a plurality of through holes connected to the hollow inner cavity are opened on the outer wall of the fixed roller brush; the feed pipe of the outer shell is connected to the first valve, the discharge pipe is connected to the second valve, a cleaning pipe is provided on the side wall of the outer shell, the cleaning pipe is connected to the third valve, and the third valve is connected to the dust collector through a pipeline.

[0013] Furthermore, it also includes an inspection port, which is opened on one side of the shell. The sealing cover at the inspection port is provided with a movable sealing door, and the movable sealing door is hinged to the shell through a hinge.

[0014] Advantages of the present invention: 1. The roller brush rotates and contacts the graphite powder, intercepting the fiber foreign matter in the graphite powder by entanglement with the bristles. The graphite powder falls in the shell by gravity. Compared with the existing technology using a vibrating screen, the filtering efficiency is high. The resistance of the graphite powder flowing through the roller brush is small and the flow rate is not affected.

[0015] 2. The roller brush rotates around the turntable and rotates on its own at the same time, which is conducive to multiple contacts between the bristles and the falling graphite powder, thereby increasing the interception rate of fiber foreign matter in the graphite powder, and the processed fiber foreign matter can be effectively intercepted.

[0016] 3. The bristles of the roller brush are entangled with the fiber foreign matter, which has a good interception effect on the fiber foreign matter with a shorter length, and solves the problem of the fiber foreign matter with a shorter length leaking through the screen when the vibrating screen is repeatedly screened. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a schematic diagram of the overall structure of Example 1 of the present invention.

[0018] Figure 2 It is a partial structural cross-sectional view of the driving device of Example 1 of the present invention.

[0019] Figure 3 This is an exploded view of the structure of the roller brush according to Example 1 of the present invention.

[0020] Figure 4 This is a schematic diagram of the overall structure of Example 4 of the present invention.

[0021] Figure 5 This is a structural explosion diagram of the negative pressure cleaning device of Example 4 of the present invention.

[0022] In the figure: housing 1, roller brush 2, turntable 3, driving device 4, negative pressure cleaning device 5, first valve 6, second valve 7, third valve 8, inspection port 9, movable sealing door 10, brush roller 201, roller shaft 202, bristles 203, keyway 204, key teeth 205, shaft ring 206, fixing screw 207, fixed ring gear 401, planetary gear 402, driving shaft 403, reducer 404, driving motor 405, intake pipe 501, fixed roller brush 502, through hole 503. DETAILED DESCRIPTION

[0023] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0024] In the description of the present invention, it should be noted that the terms "center", "up", "down", "front", "back", "top", "bottom", "left", "right", "vertical", "horizontal", "inside" and "outside" etc. indicate directions or positional relationships based on the directions or positional relationships shown in the accompanying drawings. They 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. Therefore, they should not be understood as limiting the present invention.

[0025] Example 1: Figure 1 As shown, a fiber foreign body interception device in lithium battery graphite powder of the present invention comprises a shell 1, a roller brush 2, a turntable 3, a driving device 4 and an inspection port 9. A feed pipe 101 is provided on the top of the shell 1, and a discharge pipe 102 is provided on the bottom of the shell 1. Graphite powder falls into the shell 1 from the feed pipe 101 and is sent out from the discharge pipe 102. An inspection port 9 is provided on one side of the shell 1. A movable sealing door 10 is provided on the sealing cover at the inspection port 9. The movable sealing door 10 is hinged to the shell 1 through a hinge. The movable sealing door 10 is sealed with the shell 1 during normal operation. When maintenance is required for the mechanism inside the shell 1, it can be repaired through the inspection port 9.

[0026] like Figure 2 , Figure 3As shown: a driving device 4 is installed in the housing 1, and the driving device 4 includes a fixed ring gear 401, a planetary gear 402, a driving shaft 403, a reducer 404 and a driving motor 405. The reducer 404 is fixedly installed on the outside of the housing 1, and a fixed ring gear 401 is fixedly installed in the housing 1. The driving shaft 403 passes through the housing 1 and is coaxially arranged with the fixed ring gear 401. One end of the driving shaft 403 is drivingly connected to the output shaft of the reducer 404, and the other end of the driving shaft 403 is fixedly connected to the turntable 3. The input shaft of the reducer 404 is drivingly connected to the output shaft of the driving motor 405. The driving motor 405 drives the turntable 3 to rotate through the reducer 404. A plurality of roller brushes 2 are rotatably installed on the turntable 3. The roller brush 2 includes a brush roller 201, a roller shaft 202 and bristles 203. The brush roller 201 is a hollow cylinder. The roller shaft 202 is coaxially fixedly penetrated on the brush roller 201, and a plurality of rollers 203 are circumferentially arranged on the outer wall of the brush roller 201. The dry brush bristles 203, the roller shaft 202 and the turntable 3 are rotatably connected through the bearing seat, the roller shaft 202 of the roller brush 2 passes through the turntable 3 and is fixedly installed with a planetary gear 402, and the planetary gear 402 is meshed with the fixed ring gear 401 for transmission connection; when the turntable 3 rotates, the turntable 3 drives the roller shaft 202 of the roller brush 2 to rotate around the fixed ring gear 401, and the fixed ring gear 401 is fixed to the shell 1 and will not rotate. In contrast, the planetary gear 402 meshed with the fixed ring gear 401 rotates, thereby driving the roller shaft 202 to rotate. Therefore, the driving device 4 can drive the roller brush 2 on the turntable 3 to rotate around the driving shaft 403, and at the same time, the roller brush 2 on the turntable 3 rotates around the roller shaft 202. A plurality of rows of bristles 203 are provided on the roller brush 2. The bristles 203 contact and collide with the falling graphite powder, and the rotating roller brush 2 is used to entangle the fiber foreign matter in the material with the bristles 203, thereby removing the fiber foreign matter in the material.

[0027] The distance between the ends of the bristles 203 of two adjacent roller brushes 2 is 5-10mm, so that the two adjacent roller brushes 2 will not collide with each other during rotation, and can fully contact with the falling materials to avoid leakage. The brush roller 201 of the roller brush 2 is made of plastic material, and 10 rows of blind holes for fixing the bristles 203 are opened circumferentially on the surface of the brush roller 201. The bristles 203 are filled into the blind holes by a hair transplanting machine. Each cluster of the bristles 203 includes 20 stainless steel wires with a diameter of 0.4mm. The length of the bristles 203 exposed from the brush roller 201 is 0.8 times the diameter of the brush roller 201. The longer the length of the bristles 203, the more likely the stainless steel wires will collide with the materials. The easier it is to bend, the better the flexibility, and the easier it is for fibrous foreign matter to be entangled between the two stainless steel wires. However, the longer the bristles 203, the shorter the life of the bristles 203, and the easier it is to undergo plastic deformation, causing the bristles 203 to bend. The distance between the bristles 203 of two adjacent roller brushes 2 becomes larger, and material leakage occurs. Since the fibrous foreign matter in the graphite powder is usually a few millimeters to tens of millimeters in length, it is very easy to be entangled with the rotating bristles 203 or get stuck between the two stainless steel wires, and the graphite powder is a granular material and is not easy to be retained on the bristles 203. Based on this principle, the fibrous foreign matter in the graphite powder can be intercepted on the roller brush 2, thereby reducing the fibrous foreign matter content of the discharge pipe 102, thereby playing a filtering role.

[0028] After the roller brush 2 has been running for a period of time and is saturated with fiber foreign matter, the roller brush 2 needs to be disassembled for cleaning. Moreover, after repeated use of the roller brush 2, the bristles 203 will undergo plastic deformation, and the interception effect of the bristles 203 on fiber foreign matter is reduced. At this time, a new roller brush 2 needs to be replaced. In order to facilitate the replacement of the roller brush 2, the roller brush 2 is designed to be detachable, a key slot 204 is provided in the brush roller 201, and a key tooth 205 engaged with the key slot 204 is integrally formed on the roller shaft 202. A shaft ring 206 is integrally formed on the roller shaft 202, one end of the brush roller 201 abuts against the shaft ring 206, and the other end of the brush roller 201 abuts against the fixing screw 207, and the fixing screw 207 is threadedly connected to the roller shaft 202. The brush roller 201 is sleeved on the roller shaft 202, one end of which abuts against the shaft ring 206, and the other end is pressed tightly by the fixing screw 207. When replacement is required, just remove the fixing screw 207.

[0029] Example 2: A device for intercepting fibrous foreign matter in lithium battery graphite powder of the present invention, the overall structure of which is the same as that of Example 1, except that each cluster of bristles 203 on the roller brush 2 includes 50 stainless steel wires, the diameter of the stainless steel wires is 0.2 mm, and the length of the bristles 203 exposed from the brush roller 201 is 0.5 times the diameter of the brush roller 201. The thinner the diameter of the stainless steel wire of the bristles 203, the better the filtering effect on shorter length fibrous foreign matter, but the bristles 203 are more easily entangled, so a larger number of stainless steel wires are required.

[0030] Example 3: A device for intercepting fibrous foreign matter in lithium battery graphite powder of the present invention, whose overall structure is the same as that of Example 1, except that each cluster of bristles 203 on the roller brush 2 includes 40 stainless steel wires, the diameter of the stainless steel wires is 0.3 mm, and the length of the bristles 203 exposed from the brush roller 201 is 0.6 times the diameter of the brush roller 201.

[0031] Example 4: Figure 4 , Figure 5 As shown, a fiber foreign body interception device in lithium battery graphite powder of the present invention is provided, and its overall structure is the same as that of embodiment 1, except that it also includes a negative pressure cleaning device 5, and the negative pressure cleaning device 5 includes an air intake pipe 501 and a fixed roller brush 502. The driving shaft 403 of the driving device 4 is a hollow structure, and an air intake pipe 501 is coaxially penetrated in the driving shaft 403. The air intake pipe 501 is placed outside the housing 1 at one end and connected to the high-pressure gas source, and the air intake pipe 501 is placed inside the housing 1 at one end and passes through the driving shaft 403 and the rotating disk 3 and the fixed roller brush 502. The fixed roller brush 502 is fixedly connected, and bristles 203 are installed on the fixed roller brush 502. The fixed roller brush 502 is a hollow structure. The hollow inner cavity of the fixed roller brush 502 is connected to the air inlet pipe 501, and a plurality of through holes 503 connected to the hollow inner cavity are opened on the outer wall of the fixed roller brush 502; the high-pressure air source is an air compressor, which can provide high-pressure air to the hollow inner cavity of the fixed roller brush 502 through the air inlet pipe 501, and the air is ejected from the through holes 503, so as to have the effect of blowing away the fiber foreign matter entangled on the bristles 203.

[0032] The feed pipe 101 of the shell 1 is connected to the first valve 6, the discharge pipe 102 is connected to the second valve 7, and a cleaning pipe 103 is provided on the side wall of the shell 1, and the cleaning pipe 103 is connected to the third valve 8, and the third valve 8 is connected to the dust collector through a pipeline; during normal operation, the first valve 6 and the second valve 7 are opened, the cavity of the shell 1 is connected to the feed pipe 101 and the discharge pipe 102, and the third valve 8 is closed; after working for a period of time, the fiber foreign matter intercepted by the roller brush 2 is gradually saturated, and when it is necessary to clean the fiber foreign matter entangled on the roller brush 2, first close the first valve 6, temporarily stop feeding, and close the second valve 7 after the graphite powder in the shell 1 flows out, and at the same time open the third valve 8, and turn on the high-pressure air source, and jet cleaning is carried out through the through hole 503 of the fixed roller brush 502. During this period, the turntable 3 can be quickly reversed to assist in unwinding the fiber foreign matter entangled on the bristles 203, and then taken away by the air flow, and finally sucked to the dust collector through the third valve 8.

[0033] Comparative Example 1: 5 kg of graphite powder is taken out from the feed pipe 101 of the above-mentioned embodiment 1, and is repeatedly sieved by a vibrating screen until all the graphite powder on the screen is filtered to under the screen. The screen of the vibrating screen is 200 mesh. The undersize material is used as the treated graphite powder, and a fiber foreign matter treatment effect experiment is carried out to detect the treatment effect.

[0034] Comparative Example 2: The overall processing method is the same as that of Comparative Example 1, except that the screen of the vibrating screen is 250 mesh.

[0035] Comparative Example 3: The overall processing method is the same as that of Comparative Example 1, except that the screen of the vibrating screen is 300 mesh.

[0036] Fiber foreign body treatment effect experiment: Take 2.5 kg of the graphite powders treated in the above examples 1-3 and divide them into 3 groups. At the same time, take untreated graphite powders from the feed pipe 101 as a control group to perform fiber foreign matter detection. The specific experimental steps are as follows: S1. Preparation for fiber foreign body detection: Cut a 250-mesh sieve into a 5 cm × 5 cm square sieve, place the sieve in a beaker, add pure water for washing, ultrasonically treat for 30 minutes, then take out and wash with pure water three times, and take out for use.

[0037] S2. Sample screening: The samples taken above were respectively screened through a 250-mesh vibrating sieve, 2000 g of the screened samples were weighed in a beaker, and 1600 ml of anhydrous ethanol and 4000 ml of pure water were added to the screened samples and stirred into a slurry.

[0038] S3, slurry filtration: Place the above-mentioned 250-mesh square sieve in a suction filtration funnel, slowly pour the slurry into it, and after filtration, place the square sieve in a watch glass and dry it in an oven at 80°C.

[0039] S4. Counting of fiber foreign bodies: Place the dried square sieve under a microscope and search for foreign bodies row by row from left to right along an M-shaped line. When fiber foreign bodies are found, take photos and count them.

[0040] The counting results of Examples 1-3 and the control group obtained from the experimental test are shown in Table 1: Table 1:

[0041] By comparing the graphite powders treated in Examples 1-3 with the untreated graphite powders in the control group, the fiber foreign matter interception device provided by the present invention can effectively reduce the amount of fiber foreign matter in the graphite powder and has a good effect on intercepting fiber foreign matter.

[0042] At the same time, compared with the treatment effect of using a vibrating screen in Example 2 of the present invention and that in Comparative Examples 1-3, the finer the screen, the longer the number of filtrations and the longer the duration are required during the vibrating screen treatment. Although the interception rate of fiber foreign matter can be improved by selecting a screen with a larger mesh number, fiber foreign matter with a length of less than 1000 μm will pass through the mesh of the screen and be mixed into the screened material after repeated screening, and the interception effect is still not ideal.

Claims

1. A device for intercepting fiber foreign matter in lithium battery graphite powder, characterized in that: The invention comprises a housing (1), a roller brush (2), a rotating disk (3) and a driving device (4), wherein a feed pipe (101) is provided at the top of the housing (1), a discharge pipe (102) is provided at the bottom of the housing (1), and a driving device (4) is installed in the housing (1), and the driving device (4) comprises a fixed gear ring (401), a planetary gear (402), a driving shaft (403), a speed reducer (404) and a driving motor (405). The fixed gear ring (401) is fixedly installed in the housing (1), and the driving shaft (403) passes through the housing (1). The housing (1) and the fixed gear ring (401) are coaxially arranged, the other end of the driving shaft (403) is fixedly connected to the rotating disk (3), the input shaft of the reducer (404) is drivingly connected to the output shaft of the driving motor (405), the reducer (404) is fixedly installed on the outer side of the housing (1), a plurality of roller brushes (2) are rotatably installed on the rotating disk (3), the roller shaft (202) of the roller brush (2) passes through the rotating disk (3) and is fixedly installed with a planetary gear (402), and the planetary gear (402) is meshingly connected to the fixed gear ring (401).

2. The device for intercepting fiber foreign matter in lithium battery graphite powder according to claim 1, characterized in that: The roller brush (2) comprises a brush roller (201), a roller shaft (202) and bristles (203); the brush roller (201) is in the shape of a hollow cylinder; the roller shaft (202) is coaxially fixedly provided on the brush roller (201); the roller shaft (202) is rotatably connected to the rotating disk (3) via a bearing seat; and a plurality of rows of bristles (203) are provided on the outer wall of the brush roller (201) along the circumferential direction.

3. The device for intercepting fiber foreign matter in lithium battery graphite powder according to claim 2, characterized in that: A keyway (204) is provided in the brush roller (201), a key tooth (205) engaged with the keyway (204) is integrally formed on the roller shaft (202), a shaft ring (206) is integrally formed on the roller shaft (202), one end of the brush roller (201) abuts against the shaft ring (206), and the other end of the brush roller (201) abuts against a fixing screw (207), and the fixing screw (207) is threadedly connected to the roller shaft (202).

4. A device for intercepting fiber foreign matter in lithium battery graphite powder according to any one of claims 2 or 3, characterized in that: The distance between the ends of the bristles (203) of two adjacent roller brushes (2) is 5-10 mm.

5. The device for intercepting fiber foreign matter in lithium battery graphite powder according to claim 4, characterized in that: Each cluster of bristles (203) includes 20-50 stainless steel wires, and the diameter of the stainless steel wires is 0.2-0.4 mm.

6. The device for intercepting fiber foreign matter in lithium battery graphite powder according to claim 5, characterized in that: The length of the bristles (203) exposed from the brush roller (201) is 0.5-0.8 times the diameter of the brush roller (201).

7. The device for intercepting fiber foreign matter in lithium battery graphite powder according to claim 1, characterized in that: The invention also comprises a negative pressure cleaning device (5), the negative pressure cleaning device (5) comprising an air intake pipe (501) and a fixed roller brush (502), the driving shaft (403) of the driving device (4) being a hollow structure, the air intake pipe (501) being coaxially penetrated in the driving shaft (403), the air intake pipe (501) being arranged outside the housing (1) at one end and connected to a high-pressure gas source, the air intake pipe (501) being arranged inside the housing (1) at one end and passing through the driving shaft (403) and the rotating disk (3) and being fixedly connected to the fixed roller brush (502), and a brush is installed on the fixed roller brush (502). The fixed roller brush (502) is a hollow structure, the hollow inner cavity of the fixed roller brush (502) is connected to the air inlet pipe (501), and a plurality of through holes (503) connected to the hollow inner cavity are provided on the outer wall of the fixed roller brush (502); the feed pipe (101) of the outer shell (1) is connected to the first valve (6), the discharge pipe (102) is connected to the second valve (7), a cleaning pipe (103) is provided on the side wall of the outer shell (1), the cleaning pipe (103) is connected to the third valve (8), and the third valve (8) is connected to the dust collector through a pipeline.

8. The device for intercepting fiber foreign matter in lithium battery graphite powder according to claim 1, characterized in that: It also includes an inspection opening (9), which is provided on one side of the housing (1). A seal cover at the inspection opening (9) is provided with a movable sealing door (10), and the movable sealing door (10) is hingedly connected to the housing (1) via a hinge.

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