Liquid injection method for solving diaphragm whitening after formation of cylindrical full-tab lithium battery

Abstract

The invention belongs to the technical field of lithium battery production, and particularly relates to a liquid injection method for solving the problem of diaphragm whitening after formation of a cylindrical full-tab lithium battery, which comprises the following steps: S1, firstly, putting the battery into a standing cavity, and sequentially vacuumizing and filling nitrogen into the battery to discharge gas in the battery out of the battery, and enabling a retainer cup electrolyte to enter the battery; s2, gas in the roll core is discharged through high-temperature standing for a certain time, and the electrolyte enters the roll core through the capillary action, so that the primary infiltration effect of the electrolyte on the pole piece is achieved; s3, finally, the battery is vacuumized and charged with positive-pressure nitrogen again, so that the pole piece is completely infiltrated; the pole piece can be completely infiltrated by the electrolyte through two times of vacuumizing, nitrogen filling and high-temperature standing, then the formed negative pole piece can form a uniform and stable SEI film, the cycle performance is greatly improved, the problem that the diaphragm becomes white after the cylindrical full-tab battery is formed can be solved, the color of the diaphragm and the color of the pole piece are uniform after the battery is disassembled, and the service life of the battery is prolonged. And appearance abnormity is avoided.

Description

Technical Field

[0001] The invention belongs to the technical field of lithium battery production, and specifically is a liquid injection method for solving the problem that a diaphragm of a cylindrical full-ear lithium battery turns white after formation. Background Art

[0002] The lithium battery injection and infiltration process is one of the important process steps in the lithium battery production process that can ensure battery performance and cycle life. In the production process of lithium-ion batteries, the internal materials of the battery must be infiltrated with electrolyte before they can be formed and charged. The purpose of the infiltration is to allow the electrolyte to fully fill the gaps between the particles of the electrode material inside the battery and the pores of the diaphragm material, thereby ensuring the safety and electrical performance of the battery. The role of the electrolyte is to conduct ions between the positive and negative electrodes and act as a medium for charging and discharging. The above process of injecting electrolyte into the lithium battery is the lithium battery injection and infiltration process.

[0003] A Chinese patent with publication number CN201910028193.4 discloses an electrolyte infiltration method for lithium batteries, comprising the following steps: a first vacuum step, placing the lithium battery in a vacuum environment with a vacuum degree of -0.08MPa to -0.099MPa; a first normal pressure step: placing the lithium battery after the first vacuum step in a normal atmospheric pressure environment; a high pressure step: placing the lithium battery after the first normal pressure step in a high pressure environment with a pressure greater than 0.7MPa; a second normal pressure step: placing the lithium battery after the high pressure step in a normal atmospheric pressure environment; a second vacuum step: placing the lithium battery after the second normal pressure step in a vacuum environment with a vacuum degree of -0.08MPa to -0.099MPa.

[0004] In the above technology, the infiltration method is used to continuously and alternately change the environment of the lithium battery, so that the electrolyte can be fully infiltrated. At the same time, it can prevent the existence of some areas in the middle of the battery electrode after formation that are not completely infiltrated by the electrolyte, and the phenomenon of whitening of the diaphragm after formation. However, the operation is complicated, the pressure of the equipment must be changed frequently, and repeated vacuum operations are likely to damage the sealing performance of the lithium battery.

[0005] To this end, the present invention provides a liquid injection method for solving the problem of whitening of the diaphragm of a cylindrical full-tab lithium battery after formation. Summary of the invention

[0006] In order to make up for the shortcomings of the prior art, the problem that a part of the middle of the battery pole piece after formation is not completely wetted by the electrolyte as mentioned in the background art is solved.

[0007] The technical solution adopted by the present invention to solve the technical problem is: a liquid injection method for solving the problem of whitening of the diaphragm of a cylindrical full-ear lithium battery after formation according to the present invention comprises the following steps: S1: First, the battery is placed in a static chamber, and the battery is vacuumed and filled with nitrogen in turn to discharge the gas inside the battery, and the cup electrolyte enters the battery; S2: After a certain period of high temperature standing, the gas inside the winding core is discharged, and the electrolyte enters the winding core through capillary action, achieving the initial infiltration effect of the electrolyte on the electrode; S3: Finally, the battery is evacuated again and filled with positive pressure nitrogen to make the electrode completely soaked.

[0008] Preferably, the vacuum degree of the vacuum pumping in S1 is -0.092MPa, and the vacuum pumping time is 120S; the nitrogen filling pressure is 0.7MPa, and the nitrogen filling time is 600S; wherein 120S of vacuum pumping and 600S of nitrogen filling constitute one cycle, and the entire static process after liquid injection requires eight cycles.

[0009] Preferably, after the liquid is injected into S2, the battery is placed in an environment with a temperature of -45±3°C and a dew point ≤-40°C for high-temperature standing, and the high-temperature standing time is 24 hours.

[0010] Preferably, after the high-temperature standing in S3, the battery needs to be placed in a standing chamber for standing, the vacuum degree of the vacuum pumping is -0.092MPa, and the vacuum pumping time is 120S; the nitrogen filling pressure is 0.7MPa, and the nitrogen filling time is 600S; wherein 120S of vacuum pumping and 600S of nitrogen filling are one cycle, and three cycles are required.

[0011] Preferably, the static chamber comprises: Wetting box; A clamping assembly disposed inside the infiltration box; A shaking mechanism provided at the bottom of the infiltration tank; A heater fixed to the bottom of the infiltration tank; The shaking mechanism includes four sliding columns fixedly connected to the bottom of the infiltration box, and the four sliding columns are arranged circumferentially at the bottom of the infiltration box; the sliding columns all slide on the base, and the outer sides of the sliding columns are sleeved with first springs, and the first springs are fixed between the infiltration box and the base; the bottoms of the sliding columns are equipped with rollers; the bottom ends of the bases are fixedly connected to a fixed plate, and the center of the fixed plate is rotatably connected to a turntable through a bearing; the top of the turntable is fixedly connected to four triangular blocks arranged circumferentially, and the triangular blocks all cooperate with the rollers; the bottom of the fixed plate is fixedly connected to a motor through an L-shaped plate, and the output shaft of the motor is fixedly connected to a second bevel gear; the bottom of the turntable is fixedly connected to a rotating rod, and the outer side wall of the rotating rod is fixedly connected to a first bevel gear; the first bevel gear is meshed with the second bevel gear.

[0012] Preferably, the clamping assembly includes six clamping plates, two adjacent clamping plates are arranged as a pair, the clamping plates are slidably connected with a guide rod, both ends of the guide rod are fixed to the inner wall of the infiltration box, and a plurality of second springs are arranged on the outer side of the guide rod, and the second springs separate adjacent clamping plates.

[0013] Preferably, a sealing plate is tightly installed on the top of the infiltration box; one side wall of the infiltration box is connected and fixedly connected to an air inlet pipe, and the air inlet pipe is externally connected to a nitrogen bottle; the other side wall of the infiltration box is connected and fixedly connected to one end of a gas supply pipe, and the other end of the gas supply pipe is connected and fixedly connected to a vacuum pump; a pressure gauge is installed on the gas supply pipe, and an air valve is installed on the gas supply pipe.

[0014] Preferably, both side walls of the infiltration box are fixedly connected with side panels, the side panels are slidably connected with pillars, and the bottoms of the pillars are fixedly connected to the top of the base.

[0015] The beneficial effects of the present invention are as follows: 1. The liquid injection method for solving the problem of whitening of the diaphragm after formation of a cylindrical full-tab lithium battery described in the present invention allows the electrode to be completely infiltrated by the electrolyte by arranging two times of vacuuming, nitrogen filling and high-temperature standing. After that, the negative electrode can form a uniform and stable SEI film after formation, which greatly improves the cycle performance. The present invention can solve the problem of whitening of the diaphragm after formation of a cylindrical full-tab battery. After the battery is disassembled, the diaphragm color is uniform, the electrode color is uniform, and there is no appearance abnormality, thereby improving the service life of the battery.

[0016] 2. The present invention discloses a method for injecting liquid to solve the problem of whitening of the diaphragm of a cylindrical full-ear lithium battery after formation. By comparing the comparative examples with the embodiments, the battery prepared by the conventional injection method and the electrode plate infiltration method in the prior art has a residual capacity reduced to 79.9% of the initial capacity after 900 cycles, while the battery produced by the injection method and the electrode plate infiltration method of the present invention has a capacity retention rate of 91.2% after the same 900 cycles, and the battery cycle performance is improved by 11.3% year-on-year.

[0017] 3. The present invention discloses a method for injecting liquid to solve the problem of whitening of the diaphragm after formation of a cylindrical full-ear lithium battery. The method comprises the following steps: setting a triangular block and a roller for use together, turning on the motor, and the motor drives the second bevel gear to rotate through the output shaft. The second bevel gear drives the first bevel gear to rotate. The first bevel gear drives the rotating rod to rotate. The rotating rod drives the rotating disk to rotate. The rotating disk drives the triangular block to rotate. During the rotation of the triangular block, the roller passes over the triangular block, moves to the highest point and falls down. The roller drives the sliding column and the infiltration box to complete a vibration. The operation is repeated to accelerate the flow rate of the electrolyte in the lithium battery, so that the battery pole piece is fully infiltrated by the electrolyte. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The present invention will be further described below in conjunction with the accompanying drawings.

[0019] Figure 1 is a method flow chart of an embodiment of the present invention; Figure 2 is a stereogram of the present invention; Figure 3 is a cross-sectional view of the present invention; Figure 4 It is a structural schematic diagram of the triangular block and the rotating disk in the present invention; Figure 5 It is a structural schematic diagram of the splint in the present invention; Figure 6 It is a structural schematic diagram of the triangular block in the present invention; Figure 7 It is a schematic diagram of the cycle trend of battery preparation in the present invention; In the figure: 1. base; 11. turntable; 12. fixing plate; 13. rotating rod; 14. L-shaped plate; 15. first bevel gear; 16. second bevel gear; 17. motor; 18. triangular block; 19. roller; 110. first spring; 111. sliding column; 2. infiltration box; 21. support; 22. side plate; 23. clamping plate; 24. guide rod; 25. second spring; 3. vacuum pump; 31. air pipe; 32. air valve; 33. pressure gauge; 4. air inlet pipe; 5. sealing plate; 6. heater. DETAILED DESCRIPTION

[0020] In order to make the technical means, creative features, objectives and effects achieved by the present invention easy to understand, the present invention is further explained below in conjunction with specific implementation methods. Embodiment 1:

[0021] like Figures 1 to 7 As shown, a method for injecting liquid to solve the problem of whitening of the diaphragm of a cylindrical full-ear lithium battery after formation according to an embodiment of the present invention comprises the following steps: S1: First, the battery is placed in a static chamber, and the battery is vacuumed and filled with nitrogen in turn to discharge the gas inside the battery, and the cup electrolyte enters the battery; S2: After a certain period of high temperature standing, the gas inside the winding core is discharged, and the electrolyte enters the winding core through capillary action, achieving the initial infiltration effect of the electrolyte on the electrode; S3: Finally, the battery is evacuated again and filled with positive pressure nitrogen to make the electrode completely soaked.

[0022] The vacuum degree of the vacuum pumping in S1 is -0.092MPa, and the vacuum pumping time is 120S; the nitrogen filling pressure is 0.7MPa, and the nitrogen filling time is 600S; wherein 120S of vacuum pumping and 600S of nitrogen filling constitute one cycle, and the entire static process after liquid injection needs to be performed eight cycles.

[0023] After the S2 is filled, the battery is placed in an environment with a temperature of -45±3°C and a dew point ≤-40°C for high-temperature standing for 24 hours.

[0024] After the high-temperature rest in S3, the battery needs to be placed in a rest chamber for rest. The vacuum degree of the vacuum pumping is -0.092MPa, and the vacuum pumping time is 120S; the nitrogen filling pressure is 0.7MPa, and the nitrogen filling time is 600S; wherein 120S of vacuum pumping and 600S of nitrogen filling are one cycle, and three cycles are required.

[0025] Comparative Example: Inject a certain weight of electrolyte into the cup, place the cup and the battery in the static chamber, evacuate the static chamber to -0.092MPa vacuum and fill it with 0.7MPa pressure nitrogen, and repeat the two steps of evacuating and filling with nitrogen 8 times; place the battery after liquid injection and static at a temperature of -45±3℃ and a dew point of ≤-40℃ for 24 hours, so that the electrolyte inside the winding core is absorbed by the pole piece; this batch of batteries is marked as batch A when it is circulated; Example

[0026] Inject a certain weight of electrolyte into the cup, place the cup and the battery in the static chamber, evacuate the static chamber to -0.092MPa and fill it with nitrogen at a pressure of 0.7MPa, and repeat these two steps of evacuating and filling with nitrogen for 8 times; place the battery after liquid injection and static at a temperature of -45±3℃ and a dew point of ≤-40℃ for 24 hours, so that the electrolyte inside the core is absorbed by the electrode; finally, place the cup and the battery after high-temperature static back into the static chamber, evacuate the static chamber to -0.092MPa and fill it with nitrogen at a pressure of 0.7MPa, and repeat these two steps of evacuating and filling with nitrogen for 3 times; this batch of batteries is marked as batch B when circulated.

[0027] After the A and B batches of batteries obtained through the positive and negative pressure process and the conventional injection method were formed, injected twice, aged, divided into different capacities, and tested for k values, one battery from each batch with similar capacity, internal resistance, and k value was selected and marked as A1 and B1. The cycle test experiment of 0.5C charging and 1C discharging was conducted at 25°C. The number of cycles was recorded for 900 weeks. The remaining capacity retention rate of each battery is as follows:

[0028] The battery prepared by the conventional liquid injection and electrode impregnation method of the prior art has a residual capacity reduced to 79.9% of the initial capacity after 900 cycles, while the battery produced by the liquid injection and electrode impregnation method of the present invention has a capacity retention rate of 91.2% after the same 900 cycles, and the battery cycle performance is improved by 11.3% year-on-year. Embodiment 2:

[0029] like Figures 2 to 4 As shown, the static chamber includes: Infiltration tank 2; A clamping assembly disposed inside the infiltration box 2; A shaking mechanism provided at the bottom of the infiltration box 2; A heater 6 fixedly connected to the bottom of the infiltration tank 2; The shaking mechanism includes four slide columns 111 fixedly connected to the bottom of the infiltration box 2, and the four slide columns 111 are arranged circumferentially at the bottom of the infiltration box 2; the slide columns 111 all slide on the base 1, and the outer sides of the slide columns 111 are sleeved with first springs 110, and the first springs 110 are fixedly connected between the infiltration box 2 and the base 1; the bottoms of the slide columns 111 are installed with rollers 19; the bottom end of the base 1 is fixedly connected to a fixed plate 12, and the center of the fixed plate 12 is connected by an axis The bearing is rotatably connected to a turntable 11; four triangular blocks 18 are fixedly connected to the top of the turntable 11 in a circumferential arrangement, and the triangular blocks 18 are all matched with rollers 19; a motor 17 is fixedly connected to the bottom of the fixed plate 12 through an L-shaped plate 14, and a second bevel gear 16 is fixedly connected to the output shaft of the motor 17; a rotating rod 13 is fixedly connected to the bottom of the turntable 11, and a first bevel gear 15 is fixedly connected to the outer side wall of the rotating rod 13; the first bevel gear 15 is meshed with the second bevel gear 16.

[0030] When the shaking mechanism provided by the present invention is in use, the battery is placed in the infiltration box 2 through the clamping assembly, and then the sealing plate 5 is sealed to perform vacuum and nitrogen filling operations. There is a partial area in the middle of the battery electrode that is not completely infiltrated by the electrolyte. In the subsequent use, lithium precipitation may occur in the incompletely infiltrated area. The motor 17 is turned on, and the motor 17 drives the second bevel gear 16 to rotate through the output shaft. The second bevel gear 16 drives the first bevel gear 15 to rotate. The first bevel gear 15 drives the rotating rod 13 to rotate. The rotating rod 13 drives the rotating disk 11 to rotate. The rotating disk 11 drives the triangular block 18 to rotate. During the rotation of the triangular block 18, the roller 19 passes over the triangular block 18 and moves to the maximum. When the battery falls from a high point, the roller 19 drives the slide column 111 and the wetting box 2 to complete a vibration, and the operation is repeated to accelerate the flow rate of the electrolyte in the lithium battery, so that the battery pole piece is fully infiltrated with the electrolyte; wherein the first spring 110, when in use, buffers the impact force between the infiltration box 2 and the base 1, and the connection between the first spring 110 and the slide column 111 is provided with a damping to achieve a shock absorbing effect together; during the lifting and lowering movement of the infiltration box 2, the infiltration box 2 drives the side plate 22 to move, and the side plate 22 slides on the support 21, and the support 21 limits the infiltration box 2 in the vertical direction; wherein in order to accelerate the fluidity of the decomposition liquid, the decomposition liquid is heated by starting the heater 6 to improve the infiltration of the battery.

[0031] like Figure 5As shown, the clamping assembly includes six clamps 23, and two adjacent clamps 23 are arranged as a pair. A guide rod 24 is slidably connected to the clamps 23, and both ends of the guide rod 24 are fixed to the inner wall of the infiltration box 2. A plurality of second springs 25 are arranged on the outer side of the guide rod 24, and the second springs 25 separate the adjacent clamps 23.

[0032] When the clamping plates 23 provided by the present invention are in use, the battery is placed between the clamping plates 23. At this time, the second spring 25 is compressed and the battery is fixed in the wetting box 2. The clamping plates 23 not only fix the battery but also keep the electrolyte wetting the electrode.

[0033] like Figure 3 As shown, a sealing plate 5 is tightly installed on the top of the infiltration box 2; one side wall of the infiltration box 2 is connected and fixedly connected with an air inlet pipe 4, and the air inlet pipe 4 is externally connected to a nitrogen bottle; the other side wall of the infiltration box 2 is connected and fixedly connected with one end of a gas supply pipe 31, and the other end of the gas supply pipe 31 is connected and fixedly connected with a vacuum pump 3; a pressure gauge 33 is installed on the gas supply pipe 31, and a gas valve 32 is installed on the gas supply pipe 31.

[0034] When the vacuum pump 3 provided by the present invention is used, the vacuum degree of the initial vacuum pumping is -0.092MPa, and the vacuum pumping time is 120S; the nitrogen filling pressure is 0.7MPa, and the nitrogen filling time is 600S; wherein 120S vacuum pumping and 600S nitrogen filling are one cycle, and the entire static process after liquid injection needs to be cycled eight times; after the high-temperature static placement, the battery needs to be placed in the static chamber for static placement, the vacuum degree of vacuum pumping is -0.092MPa, and the vacuum pumping time is 120S ; The pressure of nitrogen filling is 0.7MPa, and the time of nitrogen filling is 600S; wherein 120S of vacuuming and 600S of nitrogen filling constitute one cycle, and three cycles are required; through two times of vacuuming, nitrogen filling and high-temperature standing, the electrode can be completely infiltrated by the electrolyte, and then the negative electrode can form a uniform and stable SEI film; the pressure gauge 33 monitors the pressure in the infiltration box 2 in real time; a sealing ring is provided at the connection between the sealing plate 5 and the infiltration box 2 to ensure that the sealing plate 5 and the infiltration box 2 are more closely fitted and have good sealing performance.

[0035] like Figure 2 As shown, the two side walls of the infiltration box 2 are fixedly connected with side plates 22, and the side plates 22 are slidably connected with pillars 21, and the bottoms of the pillars 21 are fixedly connected to the top of the base 1.

[0036] When the pillars 21 provided by the present invention are in use, the infiltration box 2 drives the side panels 22 to move during the lifting movement, and the side panels 22 slide on the pillars 21. The pillars 21 limit the infiltration box 2 in the vertical direction.

[0037] Working principle: inject a certain weight of electrolyte into the cup, place the cup and the battery inside the static chamber, evacuate the static chamber to -0.092MPa vacuum and fill it with 0.7MPa pressure nitrogen, and repeat these two steps 8 times; place the battery after liquid injection and static at a temperature of -45±3℃ and a dew point of ≤-40℃ for 24 hours, so that the electrolyte inside the winding core is absorbed by the pole piece; finally, place the cup and the battery after high temperature static back into the static chamber, evacuate the static chamber to -0.092MPa vacuum and fill it with 0.7MPa pressure nitrogen. Pressure nitrogen, vacuuming and nitrogen filling are repeated three times; by placing the battery between the clamping plates 23, the second spring 25 is compressed, the battery is fixed in the infiltration box 2, and then the sealing plate 5 is sealed, and the vacuuming and nitrogen filling operations can be performed. There is a part of the area in the middle of the battery pole piece that is not completely infiltrated by the electrolyte. In the subsequent use, the incompletely infiltrated area will have lithium precipitation. Turn on the motor 17, the motor 17 drives the second bevel gear 16 to rotate through the output shaft, and the second bevel gear 16 drives the first bevel gear 15 to rotate, and the first The bevel gear 15 drives the rotating rod 13 to rotate, the rotating rod 13 drives the rotating disk 11 to rotate, the rotating disk 11 drives the triangular block 18 to rotate, and during the rotation of the triangular block 18, the roller 19 passes over the triangular block 18, moves to the highest point and falls down, and the roller 19 drives the sliding column 111 and the infiltration box 2 to complete a vibration, repeating the operation to accelerate the flow speed of the electrolyte in the lithium battery, so that the battery pole piece is fully infiltrated with the electrolyte; wherein the first spring 110, when in use, buffers the impact force between the infiltration box 2 and the base 1, and the first spring 110 and the sliding column 1 The connection between 11 is provided with damping to achieve the effect of shock absorption; during the lifting movement of the infiltration box 2, the infiltration box 2 drives the side plate 22 to move, and the side plate 22 slides on the support 21, and the support 21 limits the infiltration box 2 in the vertical direction; in order to accelerate the fluidity of the decomposition liquid, the decomposition liquid is heated by starting the heater 6 to improve the infiltration of the battery; through two times of vacuuming, nitrogen filling and high-temperature standing, the electrode can be completely infiltrated by the electrolyte, and then the negative electrode can form a uniform and stable SEI film, which greatly improves the cycle performance.

[0038] The above shows and describes the basic principles, main features and advantages of the present invention. It should be understood by those skilled in the art that the present invention is not limited to the above embodiments. The above embodiments and descriptions are only for explaining the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, which fall within the scope of the present invention. The scope of protection of the present invention is defined by the attached claims and their equivalents.

Claims

1. A method for injecting liquid to solve the problem of whitening of the diaphragm of a cylindrical full-ear lithium battery after formation, characterized in that: The following steps are involved: S1: First, the battery is placed in a static chamber, and the battery is vacuumed and filled with nitrogen in turn to discharge the gas inside the battery, and the cup electrolyte enters the battery; S2: After a certain period of high temperature standing, the gas inside the winding core is discharged, and the electrolyte enters the winding core through capillary action, achieving the initial infiltration effect of the electrolyte on the electrode; S3: Finally, the battery is evacuated again and filled with positive pressure nitrogen to make the electrode completely soaked.

2. A method for injecting liquid to solve the problem of whitening of the diaphragm of a cylindrical full-ear lithium battery after formation according to claim 1, characterized in that: The vacuum degree of the vacuum pumping in S1 is -0.092MPa, and the vacuum pumping time is 120S; the nitrogen filling pressure is 0.7MPa, and the nitrogen filling time is 600S; wherein 120S of vacuum pumping and 600S of nitrogen filling constitute one cycle, and the entire static process after liquid injection needs to be performed eight cycles.

3. A method for injecting liquid to solve the problem of whitening of the diaphragm of a cylindrical full-ear lithium battery after formation according to claim 2, characterized in that: After the S2 is filled, the battery is placed in an environment with a temperature of -45±3°C and a dew point ≤-40°C for high-temperature standing for 24 hours.

4. A method for injecting liquid to solve the problem of whitening of the diaphragm of a cylindrical full-ear lithium battery after formation according to claim 3, characterized in that: After the high-temperature rest in S3, the battery needs to be placed in a rest chamber for rest. The vacuum degree of the vacuum pumping is -0.092MPa, and the vacuum pumping time is 120S; the nitrogen filling pressure is 0.7MPa, and the nitrogen filling time is 600S; wherein 120S of vacuum pumping and 600S of nitrogen filling are one cycle, and three cycles are required.

5. According to the method for injecting liquid to solve the problem of whitening of the diaphragm of a cylindrical full-tab lithium battery after formation according to claim 4, the static chamber comprises: Infiltration tank (2); A clamping assembly arranged inside the infiltration box (2); A shaking mechanism provided at the bottom of the infiltration box (2); A heater (6) fixedly connected to the bottom of the infiltration box (2); The invention is characterized in that: the shaking mechanism comprises four sliding columns (111) fixedly connected to the bottom of the infiltration box (2); the four sliding columns (111) are arranged circumferentially at the bottom of the infiltration box (2); the sliding columns (111) all slide on the base (1); the outer sides of the sliding columns (111) are sleeved with first springs (110); the first springs (110) are fixedly connected between the infiltration box (2) and the base (1); the bottoms of the sliding columns (111) are equipped with rollers (19); the bottom end of the base (1) is fixedly connected to a fixing plate (12); the center of the fixing plate (12) A rotating disk (11) is rotatably connected via a bearing; four triangular blocks (18) are fixedly connected to the top of the rotating disk (11) in a circumferential arrangement, and the triangular blocks (18) are all matched with rollers (19); a motor (17) is fixedly connected to the bottom of the fixing plate (12) via an L-shaped plate (14), and the output shaft of the motor (17) is fixedly connected to a second bevel gear (16); a rotating rod (13) is fixedly connected to the bottom of the rotating disk (11), and a first bevel gear (15) is fixedly connected to the outer side wall of the rotating rod (13); the first bevel gear (15) is meshed with the second bevel gear (16).

6. A method for injecting liquid to solve the problem of whitening of the diaphragm of a cylindrical full-ear lithium battery after formation according to claim 5, characterized in that: The clamping assembly includes six clamping plates (23), two adjacent clamping plates (23) are arranged as a pair, the clamping plates (23) are slidably connected with a guide rod (24), both ends of the guide rod (24) are fixed to the inner wall of the infiltration box (2), and a plurality of second springs (25) are arranged on the outer side of the guide rod (24), and the second springs (25) separate adjacent clamping plates (23).

7. A method for injecting liquid to solve the problem of whitening of the diaphragm of a cylindrical full-tab lithium battery after formation according to claim 6, characterized in that: A sealing plate (5) is tightly mounted on the top of the infiltration box (2); a side wall of the infiltration box (2) is connected and fixedly connected to an air inlet pipe (4), and the air inlet pipe (4) is externally connected to a nitrogen bottle; the other side wall of the infiltration box (2) is connected and fixedly connected to one end of an air supply pipe (31), and the other end of the air supply pipe (31) is connected and fixedly connected to a vacuum pump (3); a pressure gauge (33) is mounted on the air supply pipe (31), and an air valve (32) is mounted on the air supply pipe (31).

8. A method for injecting liquid to solve the problem of whitening of the diaphragm of a cylindrical full-tab lithium battery after formation according to claim 7, characterized in that: The two side walls of the infiltration box (2) are fixedly connected to side plates (22), the side plates (22) are slidably connected to pillars (21), and the bottoms of the pillars (21) are fixedly connected to the top of the base (1).

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