Crucible with replaceable inner shell for graphitization of negative electrode of lithium battery and replacement method

Abstract

The invention discloses a crucible with a replaceable inner shell for lithium battery negative electrode graphitization and a replacement method, and relates to the technical field of lithium battery negative electrode graphitization equipment.The crucible comprises a bottom plate, a pot body fixedly arranged on the bottom plate and an inner shell installed in the pot body, the top of the pot body is open, and a cavity is formed in the inner side wall of the pot body; the inner shell is detachably arranged in the pot body, a through opening communicated with the interior of the pot body is formed in the bottom end of the pot body, the through opening is matched with the inner shell and used for allowing the inner shell to penetrate through, and a lifting table is arranged on the bottom plate and located below the pot body in a sliding mode in the vertical direction. The bottom plate is provided with a jacking mechanism used for driving the lifting table to ascend and descend, the lifting table is provided with an end plate, and the end plate is matched with the through opening and used for sealing the through opening. On the premise that the structural strength and the performance stability of the crucible are guaranteed, the inner shell can be rapidly and conveniently replaced.

Description

Technical Field

[0001] The present application relates to the technical field of graphitization equipment for negative electrodes of lithium batteries, and in particular to a crucible with a replaceable inner shell for graphitization of negative electrodes of lithium batteries and a replacement method. Background Art

[0002] Graphitization of negative electrode materials for lithium batteries refers to the process of converting the disordered and irregular arrangement of carbon atoms into a regular arrangement of a hexagonal plane mesh structure at high temperature, so that the negative electrode material forms a purer and more complete structure. The main purpose of this process is to increase the cycle life and charge and discharge rate of the negative electrode material, and improve its high and low temperature performance and cycle performance. In the production process of graphitization of negative electrode materials for lithium batteries, the crucible, as one of the key equipment, plays a vital role. It not only needs to withstand chemical reactions in high temperature environments, but also ensure the quality of the material and the continuity of production.

[0003] At present, most common crucibles on the market adopt an integrated casting design. Although this design improves the overall strength and durability of the crucible, it also brings some problems. In practical applications, the crucible will crack during long-term use due to thermal expansion, hard object impact, incorrect installation operation, etc., causing the crucible to be unable to withstand high temperatures and melt pressure. Due to the immutability of the internal structure of the crucible, once damage occurs, the entire crucible needs to be scrapped and cannot be partially repaired or replaced, which not only increases production costs, but also affects production efficiency. Summary of the invention

[0004] In view of the problems existing in the prior art, the present application provides a crucible with a replaceable inner shell for graphitizing a negative electrode of a lithium battery and a replacement method.

[0005] In the first aspect, the present application provides a replaceable inner shell crucible for graphitizing a negative electrode of a lithium battery, which adopts the following technical solution: A crucible with a replaceable inner shell for graphitizing negative electrodes of lithium batteries comprises a bottom plate, a pot body fixedly arranged on the bottom plate, and an inner shell body installed in the pot body, wherein the top of the pot body is opened, the inner side wall of the pot body is provided with a cavity, the cavity is filled with a filler, the inner shell body is detachably arranged in the pot body, a through opening communicating with the interior of the pot body is provided at the bottom end of the pot body, the through opening is matched with the inner shell body and is used for the inner shell body to pass through, a lifting platform is provided on the bottom plate and below the pot body so as to slide in a vertical direction, a top supporting mechanism for driving the lifting platform to rise and fall is provided on the bottom plate, and an end plate is provided on the lifting platform, the end plate is matched with the through opening and is used to close the through opening.

[0006] Optionally, the supporting mechanism includes a supporting frame and a hydraulic cylinder. The supporting frame is slidably arranged on the bottom plate along a vertical direction. The lifting platform is installed on the supporting frame. The hydraulic cylinder is used to drive the supporting frame to slide.

[0007] Optionally, the lifting platform is slidably arranged on the top support frame in the horizontal direction, a return spring is installed on the top support frame, two ends of the return spring are respectively connected to the top support frame and the lifting platform, and a chamfer is arranged at the edge position of the through opening.

[0008] Optionally, the top wall of the lifting platform is provided with an annular groove along the circumference of the end plate, a positioning ring is slidably arranged in the annular groove along the direction vertical to the top wall of the lifting platform, and a first elastic member is arranged in the annular groove for driving the positioning ring to slide away from the bottom wall of the annular groove.

[0009] Optionally, the positioning ring is made of a sealing material, and the bottom wall of the pot body is provided with an annular sealing groove for the positioning ring to be inserted into.

[0010] Optionally, a receiving groove is provided on the lower side wall of the cavity, an extrusion ring is slidably arranged in the receiving groove, a driving structure for driving the extrusion ring to slide is provided on the pot body, and the extrusion ring is used to extrude the filler in the cavity.

[0011] Optionally, the driving structure includes a push rod and a second elastic member, and a through hole connected to the accommodating groove is opened at the bottom end of the pot body along the sliding direction of the extrusion ring. The push rod is slidably arranged in the through hole and is fixedly connected to the extrusion ring, and the lifting platform is used to abut the push rod, and the second elastic member is used to drive the extrusion ring to slide toward the bottom wall of the accommodating groove.

[0012] Optionally, a plurality of extrusion rods are fixedly provided on the top end of the extrusion ring, and the extrusion rods are distributed along the circumference of the extrusion ring.

[0013] Optionally, a mounting groove communicating with the cavity is formed at the top of the pot body, a pressure cover is fixed in the mounting groove by bolts, a center hole is provided on the pressure cover, and the inner shell body is inserted into the center hole.

[0014] In a second aspect, the present application provides a method for replacing a replaceable inner shell crucible for graphitizing a negative electrode of a lithium battery, using the following technical solution: A method for replacing a crucible with a replaceable inner shell for graphitizing a negative electrode of a lithium battery comprises the following steps: S1. When the inner shell is damaged and needs to be replaced, the lifting platform is driven down by the supporting mechanism to open the opening; S2. Prepare a new inner shell, place the inner shell to be replaced on the end plate of the lifting platform, and make the position of the inner shell correspond to the position of the opening at the bottom of the pot body; S3. The lifting platform is driven up through the supporting mechanism to insert the inner shell for replacement into the through-hole at the bottom of the pot body. As the lifting platform rises, the new inner shell pushes the damaged inner shell in the pot body, and the damaged inner shell is pushed out from the top of the pot body. The new inner shell replaces the original inner shell, and the inner shell is quickly replaced.

[0015] In summary, the present application includes at least one of the following beneficial technical effects: 1. The present application arranges the inner shell body detachably in the pot body. When the inner shell body is damaged, the lifting platform is driven down by the supporting mechanism to open the through hole, prepare a new inner shell body, and place the new inner shell body on the end plate of the lifting platform, and make the position of the inner shell body correspond to the through hole position at the bottom of the pot body; then, the lifting platform is driven up, the new inner shell body is inserted into the through hole at the bottom of the pot body, the damaged inner shell body is pushed out from the top of the pot body, and the new inner shell body replaces the original inner shell body, so that the inner shell body can be replaced quickly and conveniently, avoiding the problem of the traditional one-piece crucible being scrapped as a whole due to local damage, thereby reducing the production cost and ensuring the production efficiency.

[0016] 2. The present application sets a cavity on the inner wall of the pot body and fills the cavity with fillers. During the replacement of the inner shell body, the fillers are always located in the cavity. When the inner shell body is installed in the pot body, the fillers can effectively fill the gap between the pot body and the inner shell body, and play a role in heat preservation and support for the inner shell body, thereby ensuring the structural strength and performance stability of the crucible.

[0017] 3. The present application sets the lifting platform on the top support frame by sliding it in the horizontal direction, and ensures that the lifting platform automatically returns to the initial position when not affected by external forces through the setting of the reset spring. When the inner shell is installed, the position of the inner shell is automatically fine-tuned by coordinating the chamfer at the opening with the sliding lifting platform, so as to avoid rigid squeezing of the inner shell and the bottom wall of the pot body due to installation errors, thereby causing damage to the inner shell.

[0018] 4. The present application provides a positioning ring on the lifting platform, and when the inner shell is placed on the end plate, the positioning ring facilitates the positioning of the inner shell. Furthermore, the positioning ring is made of sealing material, and an annular sealing groove for inserting the positioning ring is provided on the bottom wall of the pot body. When the inner shell is replaced, the positioning ring can also act as a sealing ring to seal the gap between the lifting platform and the pot body, thereby improving the sealing between the lifting platform and the pot body.

[0019] 5. The present application provides a receiving groove on the lower side wall of the cavity and slides an extrusion ring in the receiving groove. When the inner shell is installed, the driving structure drives the extrusion ring to slide down, so that the filler in the cavity is in a relaxed state, which is convenient for the installation of the inner shell and reduces the friction between the filler and the side wall of the inner shell. After the inner shell is installed, the filler in the cavity is squeezed by the extrusion ring to fully compact the filler, thereby improving the density and uniformity of the filler; this not only helps to enhance the overall structural stability of the crucible, but also reduces the problem of uneven heat conduction caused by loose fillers, and further improves the quality and efficiency of graphitization of negative electrode materials for lithium batteries. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a schematic diagram of the overall structure of an embodiment of the present application; Figure 2 is a structural cross-sectional view of an embodiment of the present application; Figure 3 yes Figure 2 A magnified view of part A; Figure 4 It is an exploded view used to express the lifting platform in the embodiment of the present application.

[0021] Explanation of the accompanying drawings: 1. bottom plate; 11. support frame; 12. top support frame; 13. hydraulic cylinder; 14. reset spring; 2. pot body; 21. through opening; 211. chamfer; 22. annular sealing groove; 23. cavity; 231. filler; 232. accommodating groove; 233. limiting groove; 234. second placement groove; 235. second disk cover; 24. extrusion ring; 241. limiting ring; 242. extrusion rod; 25. push rod; 26. second elastic member; 27. through hole; 28. mounting groove; 29. ​​pressure cover; 3. inner shell; 4. lifting platform; 41. end plate; 42. annular groove; 421. guide groove; 43. positioning ring; 431. guide block; 44. first elastic member; 45. first placement groove; 46. first disk cover. DETAILED DESCRIPTION

[0022] The following will be combined with the attached Figure 1 -Attached Figure 4 , the technical solutions in the embodiments of the present invention are clearly and completely described. The described embodiments are only possible technical implementations of the present invention, not all possible implementations. Those skilled in the art can completely combine the embodiments of the present invention to obtain other embodiments without creative work, and these embodiments are also within the scope of protection of the present invention.

[0023] The inventor of the present application has found that in the process of graphitizing negative electrode materials of lithium batteries, the existing crucibles mostly adopt an integrated casting design. Although this design improves the overall strength and durability of the crucible, it also brings about the problem of overall scrapping due to local damage. To this end, the present application discloses a replaceable inner shell crucible for graphitizing negative electrodes of lithium batteries and a replacement method, which mainly adopts the following scheme: The present application discloses a crucible with a replaceable inner shell for graphitizing a negative electrode of a lithium battery. Figure 1 , including a bottom plate 1, a pot body 2 and an inner shell 3, a support frame 11 is fixedly arranged on the bottom plate 1, the pot body 2 is fixedly arranged on the support frame 11, and the top of the pot body 2 is opened, and the inner shell 3 is installed in the pot body 2 and is detachably connected to the pot body 2.

[0024] Reference Figure 1 , 2 In order to realize the rapid replacement of the inner shell 3, a through hole 21 communicating with the inside of the pot body 2 is opened at the bottom end of the pot body 2, and the through hole 21 is adapted to the inner shell 3 and is used for the inner shell 3 to pass through. A lifting platform 4 is slidably arranged on the bottom plate 1 and located below the pot body 2 in the vertical direction, and an end plate 41 is fixedly arranged on the top of the lifting platform 4, and the end plate 41 is adapted to the through hole 21 and is used to close the through hole 21.

[0025] Reference Figure 1 , 2 In order to drive the lifting platform 4 to move up and down, a supporting mechanism for driving the lifting platform 4 to move up and down is provided on the bottom plate 1. Specifically, the supporting mechanism includes a supporting frame 12 and a hydraulic cylinder 13. The supporting frame 12 is slidably arranged on the bottom plate 1 in the vertical direction. The lifting platform 4 is mounted on the supporting frame 12. The hydraulic cylinder 13 is fixedly mounted on the bottom plate 1, and the piston rod of the hydraulic cylinder 13 is fixedly connected to the supporting frame 12 to drive the supporting frame 12 to slide. The hydraulic cylinder 13 can select a high-pressure and high-flow model to adapt to heavy load conditions, or a low-pressure and low-flow model to adapt to light load conditions.

[0026] When the inner shell body 3 needs to be replaced, the lifting platform 4 is first lowered to open the through opening 21, a new inner shell body 3 is prepared, and the new inner shell body 3 is placed on the end plate 41 of the lifting platform 4, and the position of the inner shell body 3 corresponds to the position of the through opening 21 at the bottom of the pot body 2; thereafter, the lifting platform 4 is driven to rise, the new inner shell body 3 is inserted into the through opening 21 at the bottom of the pot body 2, the damaged inner shell body 3 is pushed out from the top of the pot body 2, and the new inner shell body 3 replaces the original inner shell body 3, thereby realizing a quick and convenient replacement of the inner shell body 3, avoiding the problem of the traditional one-piece crucible being scrapped as a whole due to local damage, thereby reducing production costs and ensuring production efficiency.

[0027] Reference Figure 2 , 3, the lifting platform 4 is slidably arranged on the top support frame 12 in the horizontal direction, and a reset spring 14 is installed on the top support frame 12. The two ends of the reset spring 14 are respectively connected to the top support frame 12 and the lifting platform 4, and a chamfer 211 is arranged at the edge of the through-port 21. The setting of the reset spring 14 can ensure that the lifting platform 4 automatically returns to the initial position when not affected by external forces. When the inner shell 3 is installed, the chamfer 211 at the position of the through-port 21 cooperates with the sliding lifting platform 4 to automatically fine-tune the position of the inner shell 3, so as to avoid the inner shell 3 being rigidly squeezed with the bottom wall of the pot body 2 due to installation errors, thereby causing damage to the inner shell 3. The design of the chamfer 211 can adopt an angle of 30°, 45° or 60° to adapt to different installation conditions.

[0028] Reference Figure 3 , 4 The top wall of the lifting platform 4 is provided with an annular groove 42 along the circumference of the end plate 41, and a positioning ring 43 is slidably arranged in the annular groove 42 along the direction vertical to the top wall of the lifting platform 4, and a plurality of guide blocks 431 are fixedly arranged on the side wall of the positioning ring 43, and the side walls of the annular groove 42 are respectively provided with guide grooves 421 for sliding of each guide block 431, and a first elastic member 44 is provided in the annular groove 42 for driving the positioning ring 43 to slide in a direction away from the bottom wall of the annular groove 42, and the first elastic member 44 includes a compression spring, which is arranged in the guide groove 421, one end of the compression spring abuts against the lower side wall of the guide groove 421, and the other end of the compression spring abuts against the guide block 431, and the positioning ring 43 extends out of the annular groove 42 under the elastic force of the compression spring, and when the inner shell 3 is placed on the end plate 41, the positioning ring 43 is convenient for preliminary positioning of the inner shell 3.

[0029] Reference Figure 3 The positioning ring 43 is made of sealing material, such as a sealing steel ring made of fluororubber, nitrile rubber or silicone rubber, and the bottom wall of the pot body 2 is provided with an annular sealing groove 22 for the positioning ring 43 to be inserted into. When the inner shell 3 is replaced, the top end of the positioning ring 43 is inserted into the annular sealing groove 22 of the bottom wall of the pot body 2, and the positioning ring 43 slides toward the bottom wall of the annular groove 42 under the influence of the reaction force of the pot body 2, so that the bottom end of the positioning ring 43 is pressed against the lower side wall of the annular groove 42, so that the positioning ring 43 can act as a sealing ring, close the gap between the lifting platform 4 and the pot body 2, and improve the sealing between the lifting platform 4 and the pot body 2.

[0030] Reference Figure 3 , 4 In order to facilitate the installation of the positioning ring 43 and the subsequent maintenance or replacement, a first placement groove 45 is opened at the top of the lifting platform 4. The first placement groove 45 is connected to the annular groove 42 and each guide groove 421 respectively, and a first disk cover 46 is fixed in the first placement groove 45 by bolts. The first disk cover 46 is annular and matches the first placement groove 45.

[0031] Reference Figure 2 , 3 The inner wall of the pot body 2 is also provided with a cavity 23, and the cavity 23 is filled with a filler 231. The filler 231 can be made of materials such as quartz sand, ceramic particles or alumina powder, which has good high temperature resistance and low thermal conductivity. It can effectively fill the gap between the pot body 2 and the inner shell 3, and play a role in heat preservation and support for the inner shell 3.

[0032] Reference Figure 3 The lower side wall of the cavity 23 is provided with a receiving groove 232, and an extrusion ring 24 is slidably arranged in the receiving groove 232. The extrusion ring 24 can be made of materials such as metal, ceramic or composite materials to adapt to different high temperature and wear resistance requirements. A limiting ring 241 is fixedly arranged on the side wall of the extrusion ring 24, and a limiting groove 233 is provided on the side wall of the receiving groove 232 for the limiting ring 241 to slide. The lower side wall of the cavity 23 is provided with a second placement groove 234 connected to the receiving groove 232 and the limiting groove 233. A second disk cover 235 is fixed in the second placement groove 234 by bolts. The second disk cover 235 is annular and matches the second placement groove 234. The setting of the second disk cover 235 facilitates the installation of the extrusion ring 24.

[0033] Reference Figure 3 A driving structure for driving the extrusion ring 24 to slide is provided on the pot body 2, and the driving structure includes a push rod 25 and a second elastic member 26. Two through holes 27 connected to the accommodating groove 232 are provided at the bottom end of the pot body 2 along the sliding direction of the extrusion ring 24. Push rods 25 are slidably penetrated in the two through holes 27, and each push rod 25 is fixedly connected to the extrusion ring 24. The second elastic member 26 includes an elastic clamping ring, which is made of elastic steel and is wavy. One end of the elastic clamping ring abuts against the limit ring 241, and the other end of the elastic clamping ring abuts against the second disk cover 235, which is used to drive the extrusion ring 24 to slide toward the bottom wall of the accommodating groove 232.

[0034] When the inner shell 3 is being installed, the lifting platform 4 slides down, separating the top rod 25 from the lifting platform 4. The extrusion ring 24 is driven down by the elastic force of the elastic clamping ring, so that the filler 231 in the cavity 23 is in a relaxed state, which is convenient for the installation of the inner shell 3 and reduces the friction between the filler 231 and the side wall of the inner shell 3. When the new inner shell 3 is replaced, the lifting platform 4 rises and contacts with each top rod 25, pushing the extrusion ring 24 to slide up and squeeze the filler 231 in the cavity 23, fully compacting the filler 231, thereby improving the density and uniformity of the filler 231; this not only helps to enhance the overall structural stability of the crucible, but also reduces the problem of uneven heat conduction caused by the looseness of the filler 231, and further improves the quality and efficiency of graphitization of the negative electrode material of the lithium battery.

[0035] Reference Figure 3A plurality of extrusion rods 242 are fixedly provided at the top of the extrusion ring 24. The extrusion rods 242 are distributed along the circumference of the extrusion ring 24. The extrusion rods 242 can be cylindrical, square or polygonal in shape to meet different extrusion requirements. The extrusion ring 24 is inserted into the filler 231. When the extrusion ring 24 slides, the fluidity inside the filler 231 is increased through the extrusion rods 242, thereby further improving the density and uniformity of the filler 231.

[0036] Reference Figure 2 In order to facilitate the replacement of the filler 231 or the replenishment of the filler 231, a mounting groove 28 connected to the cavity 23 is opened at the top of the pot body 2, and a pressure cover 29 is fixed in the mounting groove 28 by bolts. The pressure cover 29 is provided with a center hole, and the inner shell 3 is penetrated in the center hole.

[0037] The implementation principle of the inner shell replaceable crucible for graphitization of negative electrodes of lithium batteries in the embodiment of the present application is as follows: when the inner shell 3 needs to be replaced, the lifting platform 4 is first lowered to open the through opening 21, a new inner shell 3 is prepared, and the new inner shell 3 is placed on the end plate 41 of the lifting platform 4, and the position of the inner shell 3 corresponds to the position of the through opening 21 at the bottom of the pot body 2; thereafter, the lifting platform 4 is driven to rise, the new inner shell 3 is inserted into the through opening 21 at the bottom of the pot body 2, the damaged inner shell 3 is pushed out from the top of the pot body 2, and the new inner shell 3 replaces the original inner shell 3, thereby realizing fast and convenient replacement of the inner shell 3, avoiding the problem of overall scrapping of the traditional one-piece crucible due to local damage, thereby reducing production costs and ensuring production efficiency.

[0038] Furthermore, by setting a cavity 23 on the inner wall of the pot body 2 and filling the cavity 23 with a filler 231, the filler 231 is always located in the cavity 23 during the replacement of the inner shell body 3; and when the inner shell body 3 is installed in the pot body 2, the filler 231 can effectively fill the gap between the pot body 2 and the inner shell body 3, and play a role in heat preservation and support for the inner shell body 3, thereby ensuring the structural strength and performance stability of the crucible.

[0039] The present application also discloses a method for replacing a crucible with a replaceable inner shell for graphitizing a negative electrode of a lithium battery, comprising the following steps: S1. When the inner shell 3 is damaged and needs to be replaced, the lifting platform 4 is driven down by the supporting mechanism to open the through port 21. S2, prepare a new inner shell 3, place the inner shell 3 for replacement on the end plate 41 of the lifting platform 4, and make the position of the inner shell 3 correspond to the position of the through hole 21 at the bottom of the pot body 2; S3. The lifting platform 4 is driven to rise by the supporting mechanism, and the inner shell 3 to be replaced is inserted into the through-hole 21 at the bottom of the pot body 2. As the lifting platform 4 rises, the new inner shell 3 pushes the damaged inner shell 3 in the pot body 2, and the damaged inner shell 3 is pushed out from the top of the pot body 2. The new inner shell 3 replaces the original inner shell 3, and the inner shell 3 is quickly replaced.

[0040] The above are all preferred embodiments of the present application, and the protection scope of the present application is not limited thereto. Therefore, any equivalent changes made according to the structure, shape, and principle of the present application should be included in the protection scope of the present application.

Claims

1. A crucible with replaceable inner shell for graphitization of negative electrode of lithium battery, characterized in that: The invention comprises a bottom plate (1), a pot body (2) fixedly arranged on the bottom plate (1), and an inner shell (3) installed in the pot body (2); the top of the pot body (2) is open, the inner side wall of the pot body (2) is provided with a cavity (23), the cavity (23) is filled with a filler (231), the inner shell (3) is detachably arranged in the pot body (2), and the bottom end of the pot body (2) is provided with a through opening (231) communicating with the inside of the pot body (2). 1), the through opening (21) is matched with the inner shell (3) and is used for the inner shell (3) to pass through, a lifting platform (4) is slidably arranged on the bottom plate (1) and below the pot body (2) in a vertical direction, a supporting mechanism for driving the lifting platform (4) to move up and down is arranged on the bottom plate (1), an end plate (41) is arranged on the lifting platform (4), the end plate (41) is matched with the through opening (21) and is used for closing the through opening (21).

2. The inner shell replaceable crucible for graphitizing negative electrodes of lithium batteries according to claim 1, characterized in that: The supporting mechanism comprises a supporting frame (12) and a hydraulic cylinder (13); the supporting frame (12) is slidably arranged on the bottom plate (1) in a vertical direction; the lifting platform (4) is mounted on the supporting frame (12); and the hydraulic cylinder (13) is used to drive the supporting frame (12) to slide.

3. The inner shell replaceable crucible for graphitizing negative electrodes of lithium batteries according to claim 2, characterized in that: The lifting platform (4) is slidably arranged on the top support frame (12) in the horizontal direction, a return spring (14) is installed on the top support frame (12), two ends of the return spring (14) are respectively connected to the top support frame (12) and the lifting platform (4), and a chamfer (211) is arranged at the edge position of the through opening (21).

4. The inner shell replaceable crucible for graphitizing negative electrodes of lithium batteries according to claim 3, characterized in that: The top wall of the lifting platform (4) is provided with an annular groove (42) along the circumference of the end plate (41); a positioning ring (43) is provided in the inner groove of the annular groove (42) to slide along the vertical direction of the top wall of the lifting platform (4); and a first elastic member (44) is provided in the annular groove (42) to drive the positioning ring (43) to slide in a direction away from the bottom wall of the annular groove (42).

5. The inner shell replaceable crucible for graphitizing negative electrodes of lithium batteries according to claim 4, characterized in that: The positioning ring (43) is made of sealing material, and the bottom wall of the pot body (2) is provided with an annular sealing groove (22) for the positioning ring (43) to be inserted.

6. The inner shell replaceable crucible for graphitizing negative electrodes of lithium batteries according to claim 1, characterized in that: The lower side wall of the cavity (23) is provided with a receiving groove (232), an extrusion ring (24) is slidably arranged in the receiving groove (232), a driving structure for driving the extrusion ring (24) to slide is arranged on the pot body (2), and the extrusion ring (24) is used to extrude the filler (231) in the cavity (23).

7. The inner shell replaceable crucible for graphitizing negative electrodes of lithium batteries according to claim 6, characterized in that: The driving structure comprises a push rod (25) and a second elastic member (26); a through hole (27) communicating with the accommodating groove (232) is provided at the bottom end of the pot body (2) along the sliding direction of the extrusion ring (24); the push rod (25) is slidably arranged in the through hole (27) and is fixedly connected to the extrusion ring (24); the lifting platform (4) is used to abut against the push rod (25); and the second elastic member (26) is used to drive the extrusion ring (24) to slide in a direction close to the bottom wall of the accommodating groove (232).

8. The inner shell replaceable crucible for graphitizing negative electrodes of lithium batteries according to claim 6, characterized in that: A plurality of extrusion rods (242) are fixedly arranged at the top end of the extrusion ring (24), and each of the extrusion rods (242) is distributed along the circumference of the extrusion ring (24).

9. The inner shell replaceable crucible for graphitizing negative electrodes of lithium batteries according to claim 1, characterized in that: The top end of the pot body (2) is provided with a mounting groove (28) which is in communication with the mold cavity (23); a pressure cover (29) is fixed in the mounting groove (28) by means of bolts; a center hole is provided in the pressure cover (29), and the inner shell (3) is inserted into the center hole.

10. A method for replacing a replaceable inner shell crucible for graphitizing a negative electrode of a lithium battery according to any one of claims 1 to 9, characterized in that: The following steps are involved: S1. When the inner shell (3) is damaged and needs to be replaced, the lifting platform (4) is driven down by the supporting mechanism to open the opening (21); S2, prepare a new inner shell (3), place the inner shell (3) to be replaced on the end plate (41) of the lifting platform (4), and make the position of the inner shell (3) correspond to the position of the opening (21) at the bottom of the pot body (2); S3, the lifting platform (4) is driven to rise by the supporting mechanism, and the inner shell (3) to be replaced is inserted into the through opening (21) at the bottom of the pot body (2), and as the lifting platform (4) rises, the new inner shell (3) pushes the damaged inner shell (3) in the pot body (2), and the damaged inner shell (3) is pushed out from the top of the pot body (2), and the new inner shell (3) replaces the original inner shell (3), thereby completing the rapid replacement of the inner shell (3).

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