Infiltration method of cylindrical lithium battery

Abstract

The invention discloses an infiltration method of a cylindrical lithium battery, which comprises the following steps: vacuum liquid injection: providing a dry cylindrical lithium battery, carrying out vacuum pretreatment on the cylindrical lithium battery, and injecting an electrolyte into the cylindrical lithium battery by an electrolyte needle. Placing the cylindrical lithium battery in a high-temperature and high-pressure tank body. And high-temperature formation: the formation system is set as follows: low-rate current 0.05 C is used for pre-charging, and then 0.1 C charging is carried out. And secondary liquid injection: performing vacuum pretreatment on the cylindrical lithium battery for multiple times, and injecting the electrolyte into the cavity from the liquid injection hole by the electrolyte needle head. And high-pressure pressure maintaining: transferring the cylindrical lithium battery into a high-pressure tank body for pressure maintaining. Sealing and shelving: sealing the cylindrical lithium battery, and shelving and storing the cylindrical lithium battery in a normal-temperature environment. The method can greatly shorten 48 hours or even longer shelving time required by high-temperature shelving in the traditional process, can reduce the production cost, and can improve the production efficiency.

Description

Technical Field

[0001] The invention relates to the technical field of lithium ion batteries, and in particular to an impregnation method for a cylindrical lithium battery. Background Art

[0002] Lithium iron phosphate batteries have the advantages of high voltage, high specific energy, long charge and discharge life, no memory effect and low environmental pollution. They are widely used in various fields such as industrial production and life. With the rapid development of new energy vehicles and portable power tools and the demand for miniaturization of various electrical equipment, people have higher and higher requirements for the energy density of lithium ions. In order to increase the capacity, high-capacity and high-density materials are developed for lithium batteries. As the compaction density of the battery cell pole piece continues to increase, the difficulty of wetting the pole piece is also increased. In order to produce better lithium-ion batteries, the wetting process in its production must be optimized. Lithium-ion batteries can be divided into square and cylindrical according to the shape of the battery. Among them, cylindrical lithium batteries use a winding process and have a high shell-into-shell ratio. The traditional process requires 48 hours or even longer high-temperature storage, which has problems such as difficulty in injection and slow wetting. Summary of the invention

[0003] The invention provides an infiltration method for a cylindrical lithium battery, so as to solve the problems of difficult liquid injection and slow infiltration of cylindrical lithium batteries in the prior art.

[0004] In order to solve the above technical problems, the technical solution adopted by the present invention is to provide a cylindrical lithium battery impregnation method, comprising the following steps:

[0005] Vacuum injection: providing a dry cylindrical lithium battery, performing vacuum pretreatment on the cylindrical lithium battery, and injecting electrolyte into the cylindrical lithium battery with an electrolyte needle.

[0006] High temperature and high pressure storage: The cylindrical lithium battery is transferred into a high temperature and high pressure tank.

[0007] High temperature formation: The formation system is set to pre-charge with a small rate current of 0.05C and then switch to 0.1C charging.

[0008] Secondary liquid injection: the cylindrical lithium battery is subjected to the vacuum pretreatment for multiple times, and the electrolyte needle injects the electrolyte into the cavity from the injection hole.

[0009] High-pressure maintenance: The cylindrical lithium battery is transferred into a high-pressure tank for pressure maintenance.

[0010] Sealing and storage: The cylindrical lithium battery is sealed and placed in a room temperature environment for storage.

[0011] Preferably, the vacuum pretreatment includes: placing the cylindrical lithium battery into a vacuum sealed cavity, evacuating the cavity, maintaining the pressure for a set time, and then breaking the vacuum.

[0012] Preferably, the vacuum standard is less than or equal to -0.095 MPa.

[0013] Preferably, the vacuum injection: providing a dry cylindrical lithium battery, performing vacuum pretreatment on the cylindrical lithium battery, injecting electrolyte into the cavity through the injection hole with an electrolyte needle, including: after the injection is completed, applying high voltage to the cavity multiple times through the injection hole.

[0014] Preferably, the high pressure uses nitrogen with a purity of 99.999%, and the pressure is greater than or equal to 0.8 MPa, and the pressure holding time is 4 hours.

[0015] Preferably, the high temperature and high pressure storage: the cylindrical lithium battery is transferred into a high temperature and high pressure tank, including: the storage temperature is 45°C-50°C, and the storage time is 4h.

[0016] Preferably, the high temperature formation: the formation system is set to pre-charge with a small rate current of 0.05C and then switch to 0.1C charging, including: adopting a closed-mouth formation method, the formation temperature is 30°C-35°C, the upper limit voltage is less than or equal to 3.2V, and the charging time is less than or equal to 4h.

[0017] Preferably, the injection volume of the secondary injection accounts for 10% of the total injection volume of the cylindrical lithium battery.

[0018] Preferably, the sealing and storage: the cylindrical lithium battery is sealed and placed in a room temperature environment for storage, including: the temperature of the room temperature environment is 25°C-30°C, and the storage time is 12h-15h.

[0019] Compared with the prior art, the cylindrical lithium battery impregnation method provided by the present invention has the following beneficial effects:

[0020] The cylindrical lithium battery infiltration method provided by the present invention first places the cylindrical lithium battery in a vacuum-sealed chamber for vacuum injection, and the electrolyte is completely injected into the shell. Then it is automatically transferred to a high-temperature and high-pressure tank for static placement. In this environment, the viscosity of the electrolyte decreases due to heat and the flow rate increases, and it can pass through the pores of the internal pole pieces of the battery in a short time to achieve an infiltration effect. The battery is formed at high temperature and charged with a small current, which will help the SEI structure to reorganize, form a loose and porous membrane, and improve the performance of the battery. Finally, the battery is vacuumed multiple times before the second injection, and the gas inside the battery during formation can be extracted. After the second injection, it is sealed and placed at room temperature to wait for volume separation. This method can greatly shorten the 48h high-temperature shelving required by the traditional process, or even a longer shelving time, which can reduce production costs and improve production efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for describing the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work, among which:

[0022] Figure 1 It is a process flow chart of a cylindrical lithium battery impregnation method provided by the present invention;

[0023] Figure 2 It is a three-dimensional diagram of a vacuum sealing chamber of a cylindrical lithium battery impregnation method provided by the present invention;

[0024] Figure 3 It is a three-dimensional diagram of a high-temperature and high-pressure tank body of a cylindrical lithium battery infiltration method provided by the present invention;

[0025] Figure 4 It is a structural schematic diagram of a high-pressure tank of an infiltration method for a cylindrical lithium battery provided by the present invention;

[0026] Figure 5 is a photograph of the negative electrode sheet after infiltration in Example 1 of the present invention;

[0027] Figure 6 This is a photo of the negative electrode sheet after infiltration in Comparative Example 1 of the present invention;

[0028] Figure 7 This is a photo of the negative electrode sheet after infiltration in Comparative Example 3 of the present invention;

[0029] In the figure:

[0030] 1. Cylindrical lithium battery; 2. Vacuum sealing chamber; 21. Liquid injection lower chamber; 22. Liquid injection upper chamber; 221. Liquid injection port; 3. High temperature and high pressure tank body; 31. High pressure lower tank; 311. Blower motor; 312. Heating plate; 313. Support platform; 32. High pressure upper tank; 321. Pressure gauge; 4. Tray; 41. Cup 41; 5. Locking buckle. DETAILED DESCRIPTION

[0031] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0032] refer to Figure 1 to Figure 4 , Figure 1A process flow chart of a cylindrical lithium battery impregnation method provided by an embodiment of the present invention is shown; Figure 2 A three-dimensional diagram of a vacuum sealing chamber in an infiltration method of a cylindrical lithium battery provided by an embodiment of the present invention is shown; Figure 3 A three-dimensional diagram of a high-temperature and high-pressure tank in an infiltration method of a cylindrical lithium battery provided by an embodiment of the present invention is shown; Figure 4 A schematic structural diagram of a high-pressure lower tank in an infiltration method of a cylindrical lithium battery provided in an embodiment of the present invention is shown.

[0033] like Figure 2 As shown, the vacuum sealed chamber includes a liquid injection lower chamber and a liquid injection upper chamber, and the top of the liquid injection lower chamber is along the first direction ( Figure 2 The upper cavity for liquid injection is hollow inside and can be moved in the second direction ( Figure 2 The top of the upper liquid injection chamber is provided with a liquid injection port corresponding to the position of the liquid injection hole on the top of the cylindrical lithium battery to perform a vacuum operation and inject electrolyte into the cylindrical lithium battery through an electrolyte needle.

[0034] like Figure 3 and Figure 4 As shown, the high-temperature and high-pressure tank body includes a high-pressure lower tank and a high-pressure upper tank, which can be buckled together in the second direction and locked and sealed by locking buckles on both sides. The inner walls of the high-pressure lower tank and the high-pressure upper tank are both provided with heating plates for heating the cylindrical lithium battery. The high-pressure lower tank is provided with two support platforms spaced apart along the first direction. The support platforms can be telescopically adjusted along the second direction, and the top is arranged to be arranged along the third direction ( Figure 2 The slideway extending in the Y direction (shown in the middle) facilitates the transportation of pallets loaded with cylindrical lithium batteries. A blower motor is also provided in the high-pressure lower tank, which is located between the two supporting platforms and is used to quickly transfer heat to the battery surface. A pressure gauge is provided on the outside of the high-pressure upper tank to confirm the internal pressure of the tank.

[0035] The following is a detailed description of the infiltration method of the cylindrical lithium battery provided by the present invention with specific examples. If no specific experimental steps or conditions are specified in the examples, the conventional experimental steps or conditions described in the literature in the field can be used. If the manufacturer of the reagents or instruments used is not specified, they are all conventional reagent products that can be purchased commercially.

[0036] Embodiment 1

[0037] S1, vacuum injection, the dried cylindrical lithium battery 1 is clamped by the clamp and automatically placed in the lower injection chamber 21, then the upper injection chamber 22 is closed, and the chamber is evacuated through the injection port 221, the vacuum degree is set to -0.095MPa, and the pressure is maintained for 60s before breaking the vacuum. The electrolyte needle injects electrolyte into the chamber through the injection port 221 of the upper chamber 22. After the injection is completed, cyclic high pressure is applied through the injection port 221, 0→0.4MPa→0.6MPa as one cycle, and a total of 5 cycles are performed to completely inject the electrolyte into the battery shell;

[0038] S2, high temperature and high pressure are put on hold. After the filling is completed, the cylindrical lithium battery 1 is automatically placed on the tray 4 by the mechanical gripper. After the tray 4 is full, the manipulator presses the sleeve cup 41 on the cylindrical lithium battery 1. At this time, the hole at the lower end of the sleeve cup 41 fits the injection hole of the cylindrical lithium battery. The entire tray 4 automatically enters the high-pressure lower tank body 31, and the high-pressure upper tank body 32 is slowly closed. The locking buckle 5 is overlapped and locked by the external buckle and the locking buckle to ensure that the tank body does not move when high pressure is applied, ensuring production safety. The heating plate 32 is turned on and heated to the set temperature of 45°C, and then the temperature is quickly transferred to the battery surface through the blower motor 311. At the same time, a high pressure of 0.8MPa is added to the tank body, and the pressure change is observed through the pressure gauge 321 shell. After the setting is completed and maintained for 4h, it ends.

[0039] S3, high temperature formation, the cylindrical lithium battery that has completed high temperature and high pressure maintenance is immediately transferred to the high-voltage formation cabinet, the temperature is 30℃, the formation current is 0.05C for 2h, then turned to 0.1C and continued for 1h to complete the formation.

[0040] S4, secondary injection: secondary injection is carried out after the formation is completed. The injection volume is 10% of the total injection volume, and the injection method is the same as the primary injection.

[0041] S5, high pressure maintenance, the secondary liquid injection is completed and automatically transferred to the high-pressure tank. The secondary liquid injection volume is less than that of the primary liquid injection. At this time, the high-pressure tank does not need to be heated to a high temperature, and the normal high pressure of 0.8MPa can be maintained for 2 hours.

[0042] S6. Sealing and setting aside. After the pressure holding is completed, the sealing process is started. After the sealing is completed, it is placed in the room temperature area at 25℃-30℃ and set aside for 12 hours before volume separation.

[0043] Disassemble the cylindrical lithium battery to check the infiltration of the electrode. Figure 5 This is a photo of the negative electrode after infiltration. It can be seen from the figure that the color of the electrode using this invention is uniform. The photos of other embodiments are similar to this embodiment and are not listed here.

[0044] Embodiment 2

[0045] This embodiment 2 provides a method for impregnating a cylindrical lithium battery, and the specific steps are as follows:

[0046] S1, vacuum injection, the dried and qualified cylindrical lithium battery 1 is clamped by the clamp and automatically placed in the lower injection chamber 21, and then the upper injection chamber 22 is closed, and the chamber is evacuated through the injection port 221, the vacuum degree is set to -0.095MPa, and the pressure is maintained for 60s before breaking the vacuum. The electrolyte needle injects electrolyte into the chamber through the injection port 221 of the upper chamber 22. After the injection is completed, a cyclic high pressure is applied through the injection port 221, 0→0.4MPa→0.6MPa as a cycle, and a total of 5 cycles are performed to completely inject the electrolyte into the battery shell;

[0047] S2, high temperature and high pressure are put on hold. After the filling is completed, the cylindrical lithium battery 1 is automatically placed on the tray 4 by the mechanical gripper. After the tray 4 is full, the manipulator presses the sleeve cup 41 on the cylindrical lithium battery 1. At this time, the hole at the lower end of the sleeve cup 41 fits the filling hole of the cylindrical lithium battery. The entire tray 4 automatically enters the high-pressure lower tank body 31, and the high-pressure upper tank body 32 is slowly closed. The locking buckle 5 is overlapped and locked by the external buckle and the locking buckle to ensure that the tank body does not move when high pressure is applied, ensuring production safety. The heating plate 32 is turned on and heated to the set temperature of 45°C, and then the temperature is quickly transferred to the battery surface through the blower motor 311. At the same time, a high pressure of 1.0MPa is added to the tank body, and the pressure change is observed through the pressure gauge 321 shell. After the setting is completed and maintained for 4h, it ends.

[0048] S3, high temperature formation, the cylindrical lithium battery that has completed high temperature and high pressure maintenance is immediately transferred to the high-voltage formation cabinet, the temperature is 30℃, the formation current is 0.05C for 2h, then turned to 0.1C and continued for 1h to complete the formation.

[0049] S4, secondary injection: secondary injection is carried out after the formation is completed. The injection volume is 10% of the total injection volume, and the injection method is the same as the primary injection.

[0050] S5, high pressure maintenance, the secondary liquid injection is completed and automatically transferred to the high-pressure tank. The secondary liquid injection volume is less than that of the primary liquid injection. At this time, the high-pressure tank does not need to be heated to a high temperature, and the normal high pressure of 0.8MPa can be maintained for 2 hours.

[0051] S6, seal and set aside, after the pressure holding is completed, enter the sealing process. After the sealing is completed, put it in the room temperature area at 25℃-30℃ and set aside for 12 hours before dividing the volume.

[0052] Disassemble the cylindrical lithium battery to check the infiltration condition of the electrode.

[0053] Comparative Example 1

[0054] This comparative example provides a method for impregnating a cylindrical lithium battery, and the specific steps are as follows:

[0055] S1, vacuum injection, the dried and qualified cylindrical lithium battery 1 is clamped by the clamp and automatically placed in the lower injection chamber 21, and then the upper injection chamber 22 is closed, and the chamber is evacuated through the injection port 221, the vacuum degree is set to -0.095MPa, and the pressure is maintained for 60s before breaking the vacuum. The electrolyte needle injects electrolyte into the chamber through the injection port 221 of the upper chamber 22. After the injection is completed, a cyclic high pressure is applied through the injection port 221, 0→0.4MPa→0.6MPa as a cycle, and a total of 5 cycles are performed to completely inject the electrolyte into the battery shell;

[0056] S2, high temperature and high pressure are shelved. After the filling is completed, the cylindrical lithium battery 1 is automatically placed on the tray 4 through the mechanical gripper. After the tray 4 is full, the manipulator presses the sleeve cup 41 on the cylindrical lithium battery 1. At this time, the hole at the lower end of the sleeve cup 41 fits the injection hole of the cylindrical lithium battery. The entire tray 4 automatically enters the high-pressure lower tank body 31, and the high-pressure upper tank body 32 is slowly closed. The locking buckle 5 is overlapped and locked by the external buckle and the locking buckle to ensure that the tank body does not move when high pressure is applied, ensuring production safety. The heating plate 32 is turned on and heated to the set temperature of 45°C, and then the temperature is quickly transferred to the battery surface through the blower motor 311. At the same time, a high pressure of 0.8MPa is added to the tank body, and the pressure change is observed through the pressure gauge 321 shell. After the setting is completed and maintained for 2h, it ends.

[0057] S3, high temperature formation, the cylindrical lithium battery that has completed high temperature and high pressure maintenance is immediately transferred to the high-voltage formation cabinet, the temperature is 30℃, the formation current is 0.05C for 2h, then turned to 0.1C and continued for 1h to complete the formation.

[0058] S4, secondary injection: secondary injection is carried out after the formation is completed. The injection volume is 10% of the total injection volume, and the injection method is the same as the primary injection.

[0059] S5, high pressure maintenance, the secondary liquid injection is completed and automatically transferred to the high-pressure tank. The secondary liquid injection volume is less than that of the primary liquid injection. At this time, the high-pressure tank does not need to be heated to a high temperature, and the normal high pressure of 0.8MPa can be maintained for 2 hours.

[0060] S6, seal and set aside, after the pressure holding is completed, enter the sealing process. After the sealing is completed, put it in the room temperature area at 25℃-30℃ and set aside for 12 hours before dividing the volume.

[0061] Disassemble the cylindrical lithium battery to check the infiltration of the electrode. Figure 6 This is a photo of the negative electrode after infiltration. It can be seen from the figure that a few black lines appear in the middle of the electrode without using this invention, and the electrode has slight lithium deposition. The photos of comparative example 2 and this comparative example are similar and are not listed again.

[0062] Comparative Example 2

[0063] This comparative example provides a method for impregnating a cylindrical lithium battery, and the specific steps are as follows:

[0064] S1, vacuum injection, the dried and qualified cylindrical lithium battery 1 is clamped by the clamp and automatically placed in the lower injection chamber 21, and then the upper injection chamber 22 is closed, and the chamber is evacuated through the injection port 221, the vacuum degree is set to -0.095MPa, and the pressure is maintained for 60s before breaking the vacuum. The electrolyte needle injects electrolyte into the chamber through the injection port 221 of the upper chamber 22. After the injection is completed, a cyclic high pressure is applied through the injection port 221, 0→0.4MPa→0.6MPa as a cycle, and a total of 5 cycles are performed to completely inject the electrolyte into the battery shell;

[0065] S2, put on hold at high temperature and high pressure, the cylindrical lithium battery 1 after liquid injection is automatically placed on the tray 4 by the mechanical gripper, after the tray 4 is full, the manipulator presses the sleeve cup 41 on the cylindrical lithium battery 1, at this time the hole at the lower end of the sleeve cup 41 fits with the injection hole of the cylindrical lithium battery. The entire tray 4 automatically enters the high-pressure lower tank body 31, the high-pressure upper tank body 32 is slowly closed, the locking buckle 5 is overlapped, and the external buckle is locked with the locking buckle to ensure that the tank body does not move when high pressure is applied, thereby ensuring production safety. The heating plate 32 turns off the heating function. At the same time, add a high pressure of 0.8MPa to the tank body, and observe the pressure change through the pressure gauge 321 shell. After the setting is completed and maintained for 4 hours, it ends.

[0066] S3, high temperature formation, the cylindrical lithium battery that has completed high temperature and high pressure maintenance is immediately transferred to the high-voltage formation cabinet, the temperature is 30℃, the formation current is 0.05C for 2h, then turned to 0.1C and continued for 1h to complete the formation.

[0067] S4, secondary injection: secondary injection is carried out after the formation is completed. The injection volume is 10% of the total injection volume, and the injection method is the same as the primary injection.

[0068] S5, high pressure maintenance, the secondary liquid injection is completed and automatically transferred to the high-pressure tank. The secondary liquid injection volume is less than that of the primary liquid injection. At this time, the high-pressure tank does not need to be heated to a high temperature, and the normal high pressure of 0.8MPa can be maintained for 2 hours.

[0069] S6, seal and set aside, after the pressure holding is completed, enter the sealing process. After the sealing is completed, put it in the room temperature area at 25℃-30℃ and set aside for 12 hours before dividing the volume.

[0070] Disassemble the cylindrical lithium battery to check the infiltration condition of the electrode.

[0071] Comparative Example 3

[0072] This comparative example provides a method for impregnating a cylindrical lithium battery, and the specific steps are as follows:

[0073] S1, vacuum injection, the dried and qualified cylindrical lithium battery 1 is clamped by the clamp and automatically placed in the lower injection chamber 21, and then the upper injection chamber 22 is closed, and the chamber is evacuated through the injection port 221, the vacuum degree is set to -0.095MPa, and the pressure is maintained for 60s before breaking the vacuum. The electrolyte needle injects electrolyte into the chamber through the injection port 221 of the upper chamber 22. After the injection is completed, a cyclic high pressure is applied through the injection port 221, 0→0.4MPa→0.6MPa as a cycle, and a total of 5 cycles are performed to completely inject the electrolyte into the battery shell;

[0074] S2. High temperature and high pressure storage: the cylindrical lithium battery 1 after liquid injection is placed at room temperature and pressure for 4 hours.

[0075] S3, high temperature forming, then transfer to high pressure forming cabinet, temperature 30℃, forming current 0.05C for 2h, then turn to 0.1C and continue for 1h to complete the forming.

[0076] S4, secondary injection: secondary injection is carried out after the formation is completed. The injection volume is 10% of the total injection volume, and the injection method is the same as the primary injection.

[0077] S5, high pressure maintenance, the secondary liquid injection is completed and automatically transferred to the high-pressure tank. The secondary liquid injection volume is less than that of the primary liquid injection. At this time, the high-pressure tank does not need to be heated to a high temperature, and the normal high pressure of 0.8MPa can be maintained for 2 hours.

[0078] S6, seal and set aside, after the pressure holding is completed, enter the sealing process. After the sealing is completed, put it in the room temperature area at 25℃-30℃ and set aside for 12 hours before dividing the volume.

[0079] Disassemble the cylindrical lithium battery to check the infiltration of the electrode. Figure 7 This is a photo of the negative electrode after infiltration. It can be seen from the figure that an obvious black line appears in the middle of the electrode that does not use this invention, because the battery is not fully infiltrated and the negative electrode cannot be fully embedded with lithium during the charge and discharge process.

[0080] The above examples and comparative examples were tested, with 6 units in each test. After the test, the units were disassembled at different capacities and fully charged. The disassembly results are summarized as follows:

[0081] Table 1

[0082] Serial number Wetting conditions Full power interface Example 1 High temperature 45℃ high pressure 0.8MPa stand for 4h 6 interfaces without lithium deposition Example 2 High temperature 45℃ high pressure 1.0MPa stand for 4h 6 interfaces without lithium deposition Comparative Example 1 High temperature 45℃ high pressure 0.8MPa stand for 2h 6. Slight lithium deposition on the interface Comparative Example 2 Normal temperature and high pressure 0.8MPa for 4h 6. Slight lithium deposition on the interface Comparative Example 3 Stand at room temperature and pressure for 4 hours 6 interfaces have severe lithium deposition

[0083] It can be seen from the data in the table that the method of the present invention can significantly improve the wetting effect of cylindrical lithium batteries regardless of the embodiment compared with the comparative example.

[0084] The above description is only an implementation mode of the present invention, and does not limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made by using the contents of the present invention specification and drawings, or directly or indirectly used in other related technical fields, should be included in the protection scope of the present invention.

Claims

1. A method for impregnating a cylindrical lithium battery, characterized in that: The infiltration method comprises the following steps: Vacuum injection: providing a dry cylindrical lithium battery, performing vacuum pretreatment on the cylindrical lithium battery, and injecting electrolyte into the cylindrical lithium battery with an electrolyte needle; High temperature and high pressure storage: the cylindrical lithium battery is transferred into a high temperature and high pressure tank; High temperature formation: The formation system is set to pre-charge with a low rate current of 0.05C and then switch to 0.1C charging; Secondary injection: performing the vacuum pretreatment on the cylindrical lithium battery for multiple times, and injecting electrolyte into the cavity through the injection hole with the electrolyte needle; High-pressure maintenance: the cylindrical lithium battery is transferred into a high-pressure tank for pressure maintenance; Sealing and storage: The cylindrical lithium battery is sealed and placed in a room temperature environment for storage.

2. The method for impregnating a cylindrical lithium battery according to claim 1, characterized in that: The vacuum pretreatment includes: placing the cylindrical lithium battery into a vacuum sealed cavity, evacuating the cavity, and breaking the vacuum after maintaining the pressure for a set time.

3. The method for impregnating a cylindrical lithium battery according to claim 2, characterized in that: The vacuum standard is less than or equal to -0.095MPa.

4. The method for impregnating a cylindrical lithium battery according to claim 1, characterized in that: The vacuum injection: providing a dry cylindrical lithium battery, performing vacuum pretreatment on the cylindrical lithium battery, and injecting electrolyte into the cavity through the injection hole with an electrolyte needle, including: after the injection is completed, applying high voltage to the cavity multiple times through the injection hole.

5. The method for impregnating a cylindrical lithium battery according to claim 4, characterized in that: The high pressure uses nitrogen with a purity of 99.999%, and the pressure is greater than or equal to 0.8 MPa, and the pressure maintenance time is 4 hours.

6. The method for impregnating a cylindrical lithium battery according to claim 1, characterized in that: The high temperature and high pressure storage: the cylindrical lithium battery is transferred into a high temperature and high pressure tank, including: the storage temperature is 45°C-50°C, and the storage time is 4h.

7. The method for impregnating a cylindrical lithium battery according to claim 1, characterized in that: The high temperature formation: the formation system is set to pre-charge with a small rate current of 0.05C and then switch to 0.1C charging, including: adopting a closed-mouth formation method, the formation temperature is 30°C-35°C, the upper limit voltage is less than or equal to 3.2V, and the charging time is less than or equal to 4h.

8. The method for impregnating a cylindrical lithium battery according to claim 1, characterized in that: The injection volume of the secondary injection accounts for 10% of the total injection volume of the cylindrical lithium battery.

9. The method for impregnating a cylindrical lithium battery according to claim 1, characterized in that: The sealing and storage: the cylindrical lithium battery is sealed and placed in a room temperature environment for storage, including: the temperature of the room temperature environment is 25°C-30°C, and the storage time is 12h-15h.

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