Method for Optimizing Electrolyte Infiltration in Cylindrical Batteries

Abstract

The present invention discloses a method for optimizing the electrolyte infiltration of cylindrical batteries, which relates to the technical field of electrolyte infiltration. The specific steps of this method are as follows: S100, high-pressure and vacuum liquid injection: Place the battery cell in a vacuum environment, inject the electrolyte into the battery cell through a high-pressure pump, uniformly and quickly penetrate into the inside of the electrode sheet, and detect the battery cell. S200, aging at room temperature: Place the battery cell injected with the electrolyte in a constant room-temperature environment for aging, allowing the electrolyte to fully contact the electrode sheet, promoting the uniform distribution and penetration of the electrolyte, and monitoring the aging process to ensure that the electrolyte can fully penetrate into all parts of the electrode sheet. By adopting the method of high-pressure and vacuum liquid injection and combining with gradient cyclic liquid injection, the present invention ensures that the electrolyte can fully and uniformly penetrate into the electrode sheet. Especially for batteries with relatively thick electrode sheets, it can significantly improve the infiltration effect, enhance the infiltration uniformity and infiltration depth of the electrolyte, and thus increase the liquid absorption capacity of the battery.

Description

Technical Field

[0001] The invention relates to the technical field of electrolyte infiltration, and in particular to an electrolyte infiltration method for optimizing cylindrical batteries. Background Art

[0002] In the manufacturing process of lithium-ion batteries, the wetting effect of the electrolyte has a crucial impact on the performance of the battery. The electrolyte not only plays the role of transmitting ions between the positive and negative electrodes, but also directly affects the key performance indicators of the battery, such as capacity, internal resistance and cycle life. However, in the existing lithium-ion battery manufacturing process, especially in the production of cylindrical batteries with thicker electrodes, the electrolyte wetting problem is particularly prominent.

[0003] The traditional electrolyte infiltration method for cylindrical batteries usually involves injection under high pressure and vacuum conditions, followed by aging, precharging, aging and capacity separation. However, this method has many problems for batteries with thicker pole pieces. For example, during the electrolyte infiltration process of cylindrical batteries, due to the thick pole pieces, the traditional electrolyte infiltration method is difficult to fully penetrate into the interior of the pole piece, resulting in poor infiltration of the internal area of the pole piece, and even the appearance of uninfiltrated "dry areas", which not only reduces the capacity of the battery, but may also cause the battery temperature to rise due to increased internal resistance, thereby causing thermal runaway safety issues. Secondly, when the electrolyte cannot fully infiltrate the pole piece, lithium ions are easily deposited on the surface of the negative electrode to form lithium metal during charging, thereby causing lithium precipitation, posing a threat to the safety and stability of the battery.

[0004] Therefore, how to effectively optimize the electrolyte wetting effect of cylindrical batteries has become an urgent problem to be solved in the current battery manufacturing field. Although the traditional liquid injection method can meet the wetting requirements to a certain extent, the wetting effect is often not ideal when the electrode is thicker. Therefore, a method for optimizing the electrolyte wetting of cylindrical batteries is proposed. Summary of the invention

[0005] The purpose of the present invention is to make up for the shortcomings of the prior art and provide an electrolyte infiltration method for optimizing cylindrical batteries. It can ensure that the electrolyte can evenly penetrate into the electrode through high-pressure and vacuum liquid injection, effectively solving the problem of poor wetting effect when the electrode is thicker. By introducing room temperature aging and high temperature aging steps, it promotes full contact between the electrolyte and the electrode, further improving the wetting effect. The stepped pre-charging method not only activates the battery, but also optimizes the battery performance through multiple charge and discharge tests, significantly improves the battery's liquid absorption, and improves the battery performance.

[0006] In order to solve the above technical problems, the present invention provides the following technical solutions: optimizing the electrolyte infiltration method of cylindrical batteries, the infiltration method comprising:

[0007] S100, High-pressure and Vacuum Liquid Injection: Place the battery cell in a vacuum environment, inject the electrolyte into the battery cell through a high-pressure pump, allowing it to uniformly and rapidly penetrate into the internal electrodes, and then detect the battery cell.

[0008] S200, Ambient Temperature Aging: Place the battery cell with injected electrolyte in a constant ambient temperature environment for aging, enabling the electrolyte to fully contact the electrodes, promoting the uniform distribution and penetration of the electrolyte, and monitoring the aging process to ensure that the electrolyte can fully penetrate into all parts of the electrodes.

[0009] S300, First Pre-charge: Perform a first pre-charge on the aged battery cell, charging it with a relatively small current to initially activate the battery and check whether the battery performance is normal.

[0010] S400, High-temperature Aging: Place the battery in a high-temperature environment for aging to enhance the diffusion ability of the electrolyte molecules.

[0011] S500, Second High-temperature Pre-charge: Perform a second high-temperature pre-charge operation on the battery cell after high-temperature aging, using a stepped pre-charge method for three-stage pre-charge treatment to further activate the battery and ensure the uniform distribution and penetration of the electrolyte in the electrodes.

[0012] S600, Rest: After completing the second high-temperature pre-charge, let the battery rest for a period of time to make the inside of the battery reach a stable state, ensuring that the battery can maintain stable performance during subsequent use.

[0013] Furthermore, the specific steps of S100 are as follows:

[0014] S101, Vacuum Pumping: Close all outlets of the liquid injection equipment, perform a vacuum pumping operation on the chamber where the battery cell is located to remove air and impurities in the battery cell and the chamber.

[0015] S102, High-pressure Liquid Injection: Turn on the high-pressure pump, inject the electrolyte into the battery cell under high pressure, control the pressure and flow rate to ensure that the electrolyte can uniformly and rapidly penetrate into all parts of the electrodes.

[0016] S103, Pressure Maintenance: Maintain the pressure for a period of time to allow the electrolyte to fully penetrate and diffuse inside the battery cell, prevent the electrolyte from overflowing or leaking, and ensure the uniformity of the wetting effect.

[0017] S104, Exhaust and Detection: Open the exhaust port of the liquid injection equipment to discharge the excess gas and residual electrolyte in the battery cell, perform an appearance inspection and performance test on the battery cell to ensure that the wetting effect and performance of the battery cell meet the requirements.

[0018] Furthermore, the steps of S101 vacuum pumping and S102 high-pressure liquid injection are carried out in a gradient cyclic manner.

[0019] Furthermore, the specific steps of S200 are as follows:

[0020] S201, Cell placement: After high-pressure and vacuum liquid injection, take the cell out of the liquid injection equipment and place it in a normal temperature environment for aging, ensuring that the cell is in a stable and safe position to avoid external impact or vibration during the aging process;

[0021] S202, Temperature control: Conduct aging in a constant normal temperature environment to ensure sufficient contact and interaction between the electrolyte and the electrode;

[0022] S203, Time control: Precisely control the time of normal temperature aging to enable sufficient physical and chemical interactions between the electrolyte and the electrode, promoting the uniform distribution and penetration of the electrolyte;

[0023] S204, Monitoring and recording: Regularly monitor the cell and record its state changes, including measuring the temperature, voltage, and time of the cell to ensure that the cell is in a safe and stable state during the aging process;

[0024] S205, End inspection: When the time of normal temperature aging reaches the preset value, take the cell out of the aging environment and conduct an appearance inspection and performance test, including checking for abnormal conditions such as leakage and deformation, and testing its voltage and capacity performance parameters to ensure that it can meet the requirements of subsequent processes after normal temperature aging.

[0025] Furthermore, during the normal temperature aging process, precisely control the temperature in an environment of 25°C ± 2°C and control the standing time for 10h - 12h.

[0026] Furthermore, the specific steps of S300 are as follows:

[0027] S301, Cell preparation and charging setting: Take out the cell after aging and connect it to the charging equipment, ensuring that the charging equipment can precisely control the current and voltage;

[0028] S302, First-stage normal temperature charging: Charge the cell with a relatively small current, control the charging time, and gently activate the battery to avoid damage to the battery caused by too fast charging speed;

[0029] S303, Second-stage normal temperature charging: After the first-stage charging is completed, increase the charging current to continue charging to further activate the battery and check whether the battery performance is normal;

[0030] S304, Performance inspection: Real-time monitor the voltage and temperature parameters of the cell to ensure that the cell is in a safe and stable state during the charging process, and conduct performance tests such as discharge tests and internal resistance tests to evaluate the battery performance.

[0031] Further, in the first-stage normal-temperature charging of S302, the current is controlled at 0.05c, and the charging time is controlled at 2 - 3h. In the second-stage normal-temperature charging, the current is controlled at 0.2c, and the charging time is controlled at 1 - 1.5h.

[0032] Further, S400 places the battery in an environment of 35℃ ± 2℃ and allows it to stand for 7h - 8h to improve the speed, time, and effect of the electrolyte entering the electrode sheet.

[0033] Further, S500 performs a three-stage high-temperature pre-charging process, and the current and discharge time of each stage are controlled as follows:

[0034] The first stage: Charge to 3.4V at a current of 0.2 - 0.25C. After charging to 3.4V, perform a single discharge with a discharge current of 0.3 - 0.5C and a discharge time of 10s.

[0035] The second stage: Charge to 3.51 - 3.54V at a current of 0.3 - 0.35C. After charging to 3.51 - 3.54V, perform a single discharge test with a discharge current of 0.3 - 0.4C and a discharge time of 10s.

[0036] The third stage: Charge to 3.6V at a current of 0.4 - 0.45C to complete the secondary pre-charging process of the battery.

[0037] Further, the specific steps of S600 are as follows:

[0038] S601, Environment preparation: Select a clean, dust-free, constant-temperature, and constant-humidity environment to place the battery cells.

[0039] S602, Placing the battery cells: Place the battery cells steadily to avoid the battery cells from being vibrated, impacted, or externally pressed, and ensure there is enough space between the battery cells to avoid mutual contact or friction.

[0040] S603, Standing time: Set the standing time according to the battery type and manufacturing process requirements to allow various chemical reactions and physical processes inside the battery to reach equilibrium and stability.

[0041] S604, Follow-up processing: Check the performance of the battery after standing. If it passes, proceed with the subsequent packaging and testing steps. If the battery performance does not meet the requirements, further analysis and processing are carried out.

[0042] Compared with the prior art, the optimized electrolyte infiltration method for cylindrical batteries has the following beneficial effects:

[0043] 1. The present invention adopts a high-pressure and vacuum liquid injection method, combined with a gradient cyclic liquid injection, to ensure that the electrolyte can fully and uniformly penetrate into the electrode sheet. Especially for a battery with a relatively thick electrode sheet, it can significantly improve the wetting effect, enhance the wetting uniformity and wetting depth of the electrolyte, thereby increasing the liquid absorption capacity of the battery.

[0044] 2. The present invention optimizes the steps of aging, pre-charging, and standing after liquid injection, especially the stepped treatment of primary pre-charging, high-temperature aging, and secondary high-temperature pre-charging, which can fully activate the battery and optimize the distribution of the electrolyte inside the battery and the battery performance. This method can effectively reduce the occurrence of lithium plating, improve the safety and reliability of the battery, and at the same time improve the performance indicators of the battery's capacity, internal resistance, and cycle life.

[0045] Other advantages, objectives, and features of the present invention will be described to some extent in the subsequent specification, and to some extent, will be obvious to those skilled in the art based on the study of the following text, or can be taught from the practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments of the present invention, and for those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0047] Figure 1 Operation flowchart for optimizing the electrolyte wetting method of a cylindrical battery

[0048] Figure 2 Result display diagram of the embodiment and the comparative example of the wetting method for a steel shell cylindrical battery core. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0049] The following will clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, rather than all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present invention.

[0050] A method for optimizing the electrolyte wetting of a cylindrical battery, the method comprising the following steps: high-pressure and vacuum liquid injection, room-temperature aging, primary pre-charging, high-temperature aging, secondary high-temperature pre-charging, and standing.

[0051] First, enter the high-pressure and vacuum liquid injection stage (S100). Place the battery cells to be injected with liquid in a specific liquid injection device, and ensure that the battery cells are in a stable and sealed state. Close all the outlets of the liquid injection device, start the vacuum pump, and perform a vacuum pumping operation on the chamber where the battery cells are located. After reaching the predetermined vacuum degree, start the high-pressure pump and inject the electrolyte into the battery cells under high pressure. During the high-pressure liquid injection process, precisely control the pressure and flow rate. After the liquid injection is completed, maintain the pressure for a certain period of time to allow the electrolyte to fully penetrate and diffuse inside the battery cells. The duration of this pressure maintenance can be adjusted according to the specifications of the battery cells and the properties of the electrolyte. After the pressure maintenance ends, open the exhaust port of the liquid injection device to discharge the excess gas and residual electrolyte in the battery cells, and conduct an appearance inspection and performance test on the battery cells to ensure that the infiltration effect and performance of the battery cells meet the requirements.

[0052] Next, enter the normal-temperature aging stage (S200). After completing the high-pressure and vacuum liquid injection, take out the battery cells from the liquid injection device and place them in a preset normal-temperature aging environment, ensuring that the ambient temperature is within the range of 25°C ± 2°C. The normal-temperature aging time needs to be precisely controlled within the range of 10h - 12h. During this period, sufficient physical and chemical reactions will occur between the electrolyte and the electrode sheets. During this process, it is necessary to regularly monitor the battery cells and record their state changes to ensure that the battery cells are in a safe and stable state during the aging process. When the normal-temperature aging time reaches the preset value, take out the battery cells from the aging environment and conduct an appearance inspection and performance test. Check whether there are abnormal situations such as leakage and deformation of the battery cells, and test their voltage and capacity performance parameters to ensure that they can meet the requirements of subsequent processes after normal-temperature aging.

[0053] Subsequently, enter the first pre-charging stage (S300). After the normal-temperature aging is completed, take out the battery cells, connect the battery cells to the charging device, and ensure that the charging device can precisely control the current and voltage. First, charge the battery cells with a relatively small current for 2 - 3 hours. After the first-stage normal-temperature charging is completed, increase the charging current and continue to charge the battery cells for 1 - 1.5 hours. During the charging process, it is necessary to monitor parameters such as the voltage and temperature of the battery cells in real time to ensure that the battery cells are in a safe and stable state during the charging process. After the charging is completed, conduct performance tests such as discharge tests and internal resistance tests to evaluate the performance of the battery. If the battery cells show good performance after the first pre-charging, they can be transferred to the next stage (high-temperature aging) for processing. If the battery cells exhibit abnormal performance or failures, further inspections and treatments are required.

[0054] Then, enter the high-temperature aging stage (S400). After the first pre-charging is completed, remove the battery cell from the pre-charging equipment and prepare for high-temperature aging. Place the battery cell in a preset high-temperature aging equipment and control the temperature within the range of 35°C ± 2°C. Such a temperature range is conducive to the diffusion of electrolyte molecules, thus further promoting the uniform distribution and penetration of the electrolyte in the electrode sheets. Precisely control the high-temperature aging time within the range of 7h - 8h. During this period, the electrolyte molecules will accelerate diffusion and penetration under high-temperature conditions, ensuring that the electrolyte can fully penetrate into all parts of the electrode sheets. During the high-temperature aging process, it is necessary to regularly monitor the battery cell and record its state changes. The monitoring content includes parameters such as the temperature and voltage of the battery cell. When the high-temperature aging time reaches the preset value, remove the battery cell from the high-temperature aging equipment and conduct an appearance inspection and performance test. Check whether there are abnormal conditions such as leakage and deformation of the battery cell, and test its voltage and capacity performance parameters to ensure that it can meet the requirements of subsequent processes after high-temperature aging.

[0055] Finally, enter the second high-temperature pre-charging stage (S500). Conduct a second high-temperature pre-charging operation on the battery cell after high-temperature aging. Adopt a stepped pre-charging method for pre-charging treatment in three stages. First-stage charging: Charge the battery cell with a current of 0.2 - 0.25C until the voltage reaches 3.4V. Monitor the voltage and temperature of the battery cell in real time during the charging process. First-stage discharging: After the battery cell voltage reaches 3.4V, conduct a short discharging operation. Control the discharging current within 0.3 - 0.5C and the discharging time is 10 seconds, which helps to stabilize the internal state of the battery cell and prepare for the next-stage charging. Second-stage charging: After the first-stage discharging ends, continue to charge the battery cell with a current of 0.3 - 0.35C until the voltage reaches within the range of 3.51 - 3.54V. Similarly, it is necessary to monitor the voltage and temperature of the battery cell in real time during the charging process. Second-stage discharging test: After the battery cell voltage reaches 3.51 - 3.54V, conduct a discharging test. Control the discharging current within 0.3 - 0.4C and the discharging time is 10 seconds to further verify the performance and stability of the battery cell. Third-stage charging: After the second-stage discharging test ends, conduct the final charging operation on the battery cell with a current of 0.4 - 0.45C until the voltage reaches the preset value of 3.6V. At this time, the second high-temperature pre-charging process is completed. After that, conduct a series of performance inspections on the battery cell, such as internal resistance test and capacity test, to ensure that the performance of the battery cell meets the requirements.

[0056] In addition, through the static stage (S600), it can ensure that the battery can maintain stable performance during subsequent use, improving the reliability and safety of the battery.

[0057] Through the implementation of the steps of the above embodiments, the electrolyte infiltration method for optimizing cylindrical batteries provided by the present invention has been verified by actual application, and can significantly improve the infiltration effect of the battery, enhance the liquid absorption capacity and battery performance of the battery. Especially for batteries with thicker electrode sheets, this method can effectively solve the problems of poor infiltration effect and lithium deposition, and improve the safety and reliability of the battery. Example

[0058] This embodiment details the infiltration method and process of a steel shell cylindrical battery cell, explores the optimization direction of the battery cell performance through different pre-charging strategies and conditions, finely controls the pre-charging steps and conditions, compares the results of different embodiments and comparative examples, and evaluates the influence of different parameters on the battery cell performance, so as to select the best infiltration method.

[0059] The steel shell cylindrical battery cell is filled with electrolyte in a vacuum high-pressure injection manner, circulating according to the process of vacuum, pressure relief, and pressurization, injecting 12 g of electrolyte, and detecting the battery cell.

[0060] The battery cell filled with electrolyte is placed in a constant normal temperature environment of 25°C ± 2°C for aging, and left standing for 12 h to allow the electrolyte to fully contact the electrode sheet, and monitor the aging process to ensure that the electrolyte can fully penetrate into all parts of the electrode sheet.

[0061] Take out the battery cell after aging and connect it to the charging device. Control the current of the first-stage normal temperature charging to 0.05c for 2 h, and control the current to 0.2c and the charging time to 1 h during the second-stage normal temperature charging, and monitor the current and temperature parameters of the battery cell in real time.

[0062] Place the battery in a high temperature environment of 35°C ± 2°C for aging, and leave it standing for 7 h to enhance the diffusion ability of electrolyte molecules.

[0063] Perform a secondary high-temperature pre-charging operation on the battery cell after high-temperature aging. Use a stepped pre-charging method for three-stage pre-charging treatment. The first stage is to pre-charge with a current of 0.25C to 3.4V. After charging to 3.4V, perform a discharge test, discharging with a current of 0.5C for 10S. The second stage pre-charges with a current of 0.35C to 3.54V. After charging to 3.54V, perform a discharge test, discharging with a current of 0.3C for 10s. The third stage pre-charges with a current of 0.4C to 3.6V to complete the secondary pre-charging process of the battery.

[0064] Place the battery cell stably in a clean, dust-free, constant temperature and humidity environment, ensure that there is enough space between the battery cells, avoid the battery cells from being vibrated, impacted, externally pressed, contacting and rubbing against each other, and make various chemical reactions and physical processes inside the battery reach a balanced and stable state, and perform a performance inspection on the standing battery. Example

[0065] This embodiment details the infiltration method and process of steel shell cylindrical battery cells, explores the optimization direction of battery cell performance by controlling the pre-charging strategy and conditions of high-temperature aging, finely controls the pre-charging steps and conditions, compares the results of different embodiments and comparative examples, evaluates the influence of different parameters on battery cell performance, and thus selects the best infiltration method.

[0066] The steel shell cylindrical battery cells are filled with electrolyte in a vacuum high-pressure injection manner, circulating according to the process of vacuum, pressure relief, and pressurization, injecting 12 g of electrolyte, and detecting the battery cells.

[0067] The battery cells injected with electrolyte are aged in a constant normal temperature environment of 25°C ± 2°C, left standing for 12 h to allow the electrolyte to fully contact the electrode sheets, and the aging process is monitored to ensure that the electrolyte can fully penetrate into all parts of the electrode sheets.

[0068] After the aging is completed, the battery cells are taken out and connected to the charging device. The first-stage normal temperature charging is controlled at a current of 0.05c for 2 h, and the second-stage normal temperature charging is controlled at a current of 0.2c for 1 h. The current and temperature parameters of the battery cells are monitored in real time.

[0069] The battery cells after the first pre-charging are subjected to a second high-temperature pre-charging operation, and a stepped pre-charging method is used for pre-charging treatment in three stages. The first stage is to pre-charge at a current of 0.25C to 3.4V. After charging to 3.4V, a discharge test is performed, discharging at a current of 0.5C for 10S. The second stage pre-charges at a current of 0.35C to 3.54V. After charging to 3.54V, a discharge test is performed, discharging at a current of 0.3C for 10 s. The third stage pre-charges at a current of 0.4C to 3.6V to complete the second pre-charging process of the battery.

[0070] The battery cells are placed stably in a clean, dust-free, constant temperature and humidity environment, ensuring sufficient space between the battery cells to avoid the battery cells from being vibrated, impacted, externally pressed, contacting and rubbing against each other, so that various chemical reactions and physical processes inside the battery reach a balanced and stable state, and the performance of the static battery is checked. Example

[0071] This embodiment details the infiltration method and process of steel shell cylindrical battery cells, explores the optimization direction of battery cell performance by controlling the pre-charging strategy and conditions of the first-stage normal temperature pre-charging, finely controls the pre-charging steps and conditions, compares the results of different embodiments and comparative examples, evaluates the influence of different parameters on battery cell performance, and thus selects the best infiltration method.

[0072] The steel shell cylindrical battery cells are filled with electrolyte in a vacuum high-pressure injection manner, circulating according to the process of vacuum, pressure relief, and pressurization, injecting 12 g of electrolyte, and detecting the battery cells.

[0073] Place the electrolyte-injected battery cells in a constant normal-temperature environment of 25°C ± 2°C for aging, and let them stand for 12 hours to allow the electrolyte to fully contact the electrode sheets. Monitor the aging process to ensure that the electrolyte can fully penetrate into all parts of the electrode sheets;

[0074] Take out the battery cells after aging and connect them to the charging device. When charging, control the current to 0.2C and the charging time to 1 hour, and monitor the current and temperature parameters of the battery cells in real time;

[0075] Place the battery in a high-temperature environment of 35°C ± 2°C for aging, and let it stand for 7 hours to enhance the diffusion ability of the electrolyte molecules;

[0076] Perform a secondary high-temperature pre-charging operation on the battery cells after high-temperature aging. Use a stepped pre-charging method for pre-charging treatment in three stages. The first stage is to pre-charge with a current of 0.25C until 3.4V, and after charging to 3.4V, perform a discharge test, discharging with a current of 0.5C for 10S. The second stage pre-charges with a current of 0.35C until 3.54V, and after charging to 3.54V, perform a discharge test, discharging with a current of 0.3C for 10s. The third stage pre-charges with a current of 0.4C until 3.6V to complete the secondary pre-charging process of the battery;

[0077] Place the battery cells stably in a clean, dust-free, constant temperature and humidity environment, ensure there is enough space between the battery cells, and avoid the battery cells from being vibrated, impacted, externally pressured, contacting each other and rubbing, so that various chemical reactions and physical processes inside the battery reach a balanced and stable state, and perform a performance inspection on the standing battery. Example

[0078] This example details the infiltration method and process of steel shell cylindrical battery cells, explores the optimization direction of battery cell performance through the pre-charging strategy and conditions of controlling the secondary high-temperature pre-charging current, finely controls the pre-charging steps and conditions, compares the results of different examples and comparative examples, evaluates the influence of different parameters on the battery cell performance, and thus selects the best infiltration method.

[0079] The steel shell cylindrical battery cells are injected with 12g of electrolyte in the way of vacuum high-pressure injection, and the battery cells are detected according to the process of vacuum, pressure relief, and pressurization;

[0080] Place the electrolyte-injected battery cells in a constant normal-temperature environment of 25°C ± 2°C for aging, and let them stand for 12 hours to allow the electrolyte to fully contact the electrode sheets. Monitor the aging process to ensure that the electrolyte can fully penetrate into all parts of the electrode sheets;

[0081] Take out the battery cells after aging and connect them to the charging device. Control the current of the first-stage normal-temperature charging to 0.05C for 2 hours, and control the current to 0.2C and the charging time to 1 hour during the second-stage normal-temperature charging, and monitor the current and temperature parameters of the battery cells in real time;

[0082] The battery is aged at a high temperature of 35°C ± 2°C, and left standing for 7 hours to enhance the diffusion ability of the electrolyte molecules;

[0083] Perform a secondary high-temperature pre-charging operation on the cell after high-temperature aging. A stepped pre-charging method is used for pre-charging treatment in three stages. In the first stage, a current of 0.3C is pre-charged to 3.4V. After charging to 3.4V, a discharge test is performed, discharging at a current of 0.5C for 10S. In the second stage, a current of 0.5C is pre-charged to 3.54V. After charging to 3.54V, a discharge test is performed, discharging at a current of 0.3C for 10s. In the third stage, a current of 0.7C is pre-charged to 3.6V to complete the secondary pre-charging process of the battery;

[0084] Place the cells steadily in a clean, dust-free, constant temperature and humidity environment, ensuring there is enough space between the cells to avoid the cells from being vibrated, impacted, externally compressed, contacting each other and rubbing, so that various chemical reactions and physical processes inside the battery reach a balanced and stable state, and perform a performance check on the standing battery. Embodiment

[0085] This embodiment details the infiltration method and process of the steel shell cylindrical cell, and explores the optimization direction of the cell performance through the pre-charging strategy and conditions of secondary high-temperature pre-discharge control, finely controls the pre-charging steps and conditions, compares the results of different embodiments and comparative examples, evaluates the influence of different parameters on the cell performance, and thus selects the best infiltration method.

[0086] This embodiment details the infiltration method and process of the steel shell cylindrical cell, and explores the optimization direction of the cell performance through different pre-charging strategies and conditions, finely controls the pre-charging steps and conditions, compares the results of different embodiments and comparative examples, evaluates the influence of different parameters on the cell performance, and thus selects the best infiltration method.

[0087] The steel shell cylindrical cell is filled with electrolyte in a vacuum high-pressure injection manner, circulating according to the process of vacuum, pressure relief, and pressurization, injecting 12g of electrolyte, and detecting the cell;

[0088] Place the cell filled with electrolyte in a constant normal temperature environment of 25°C ± 2°C for aging, and leave it standing for 12 hours to allow the electrolyte to fully contact the electrode plate, and monitor the aging process to ensure that the electrolyte can fully penetrate into all parts of the electrode plate;

[0089] Take out the cell after aging and connect it to the charging device. Control the current of the first-stage normal temperature charging to 0.05c for 2 hours, and control the current to 0.2c and the charging time to 1 hour during the second-stage normal temperature charging, and monitor the current and temperature parameters of the cell in real time;

[0090] The battery is aged at a high temperature of 35°C ± 2°C, and left standing for 7 hours to enhance the diffusion ability of the electrolyte molecules;

[0091] Perform a secondary high-temperature pre-charging operation on the cell after high-temperature aging. A stepped pre-charging method is used for pre-charging treatment in three stages. In the first stage, pre-charge with a current of 0.25C until 3.4V, in the second stage, pre-charge with a current of 0.35C until 3.54V, and in the third stage, pre-charge with a current of 0.4C until 3.6V to complete the secondary pre-charging process of the battery;

[0092] Place the cells stably in a clean, dust-free, temperature- and humidity-controlled environment, ensuring there is enough space between the cells to avoid the cells from being vibrated, impacted, externally pressured, contacting each other and rubbing, so that various chemical reactions and physical processes inside the battery reach a balanced and stable state, and perform a performance check on the standing battery.

[0093] Comparative Example 1

[0094] This embodiment provides in detail the infiltration method and process of the steel shell cylindrical cell, and controls the pre-charging strategy and conditions.

[0095] The steel shell cylindrical cell is filled with electrolyte in a vacuum high-pressure injection manner, circulating according to the process of vacuum, pressure relief, and pressurization, injecting 12 g of electrolyte, and detecting the cell;

[0096] Place the cell filled with electrolyte in a constant normal temperature environment of 25°C ± 2°C for aging, and leave it standing for 12 hours to allow the electrolyte to fully contact the electrode sheet, and monitor the aging process to ensure that the electrolyte can fully penetrate into all parts of the electrode sheet;

[0097] Take out the cell after aging and connect it to the charging device. Charge with a current of 0.03c for 2 hours in the first stage of charging, and control the current at 0.3C during the second stage of charging until 3.6V.

[0098] In summary, through the implementation of the above embodiments, the pre-charged battery is disassembled. After disassembly, observe the single-sided and double-sided interfaces of the negative electrode sheet, measure the electrolyte absorption capacity of the wound core, and the remaining cells are aged and cycled after grading.

[0099] As Figure 2 shown in Embodiment 2, the number of cycle weeks is more than that of Comparative Example 1, the electrolyte absorption capacity of the wound core is more than that of Comparative Example 1, and no abnormality appears at the interface of the negative electrode sheet. The different embodiments and Comparative Example 1 are as Figure 2 shown.

[0100] It is obvious to those skilled in the art that the present invention is not limited to the details of the above-described exemplary embodiments, and that the present invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the present invention. Therefore, from any point of view, the embodiments should be regarded as exemplary and non-limiting. The scope of the present invention is defined by the appended claims rather than the above description. Therefore, all changes falling within the meaning and scope of the equivalent elements of the claims are intended to be embraced within the present invention. Any reference signs in the claims should not be construed as limiting the claims concerned.

Claims

1. An electrolyte infiltration method for optimizing cylindrical batteries, characterized in that, The infiltration method includes: S100, high-pressure and vacuum liquid injection: Place the battery cell in a vacuum environment, inject the electrolyte into the battery cell through a high-pressure pump, uniformly and quickly penetrate into the inside of the electrode sheet, and detect the battery cell; S200, normal temperature aging: Place the battery cell injected with the electrolyte in a constant normal temperature environment for aging, allow the electrolyte to fully contact the electrode sheet, promote the uniform distribution and penetration of the electrolyte, and monitor the aging process to ensure that the electrolyte can fully penetrate into all parts of the electrode sheet; S300, primary pre-charging: Perform primary pre-charging on the aged battery cell, charge with a relatively small current, initially activate the battery and check whether the performance of the battery is normal. The specific steps of S300 are: S301, battery cell preparation and charging setting: Take out the battery cell after the aging is completed, connect it to the charging device, and ensure that the charging device can accurately control the current and voltage; S302, first-stage normal temperature charging: Charge the battery cell with a current controlled at 0.05c and a charging time controlled at 2 - 3h, control the charging time, gently activate the battery, and avoid damage to the battery caused by too fast charging speed; S303, second-stage normal temperature charging: After the first-stage charging is completed, increase the current to 0.2c and continue charging for 1 - 1.5h to further activate the battery and check whether the performance of the battery is normal; S304, performance inspection: Real-time monitor the voltage and temperature parameters of the battery cell to ensure that the battery cell is in a safe and stable state during the charging process, and perform performance tests, including discharge tests and internal resistance tests, to evaluate the performance of the battery; S400, high temperature aging: Place the battery in a high temperature environment for aging to enhance the diffusion ability of the electrolyte molecules; S500, secondary high temperature pre-charging: Perform secondary high temperature pre-charging operation on the battery cell after high temperature aging, and perform three-stage pre-charging treatment in a stepped pre-charging manner to further activate the battery and ensure the uniform distribution and penetration of the electrolyte in the electrode sheet. S500 performs three-stage high temperature pre-charging treatment, and the current and discharge time of each stage are controlled as follows: First stage: Charge to 3.4V with a current of 0.2 - 0.25C, and perform a single discharge after charging to 3.4V. The discharge current is 0.3 - 0.5C and the discharge time is 10s; Second stage: Charge to 3.51 - 3.54V with a current of 0.3 - 0.35C, and perform a single discharge test after charging to 3.51 - 3.54V. The discharge current is 0.3 - 0.4C and the discharge time is 10s; Third stage: Charge to 3.6V with a current of 0.4 - 0.45C to complete the secondary pre-charging process of the battery; S600, standing: After the secondary high temperature pre-charging is completed, let the battery stand for a period of time to make the inside of the battery reach a stable state and ensure that the battery can maintain stable performance during subsequent use.

2. The electrolyte infiltration method for optimizing cylindrical batteries according to claim 1, characterized in that The specific steps of S100 are: S101, vacuum pumping: Close all outlets of the liquid injection device, perform vacuum pumping on the chamber where the battery cell is located, and remove the air and impurities in the battery cell and the chamber; S102, High-pressure liquid injection: Turn on the high-pressure pump, inject the electrolyte into the battery cell under high pressure, and control the pressure and flow rate to ensure that the electrolyte can penetrate evenly and quickly into all parts of the electrode sheet; S103, Pressure maintenance: Maintain the pressure for a period of time to allow the electrolyte to fully penetrate and diffuse inside the battery cell, prevent the electrolyte from overflowing or leaking, and ensure the uniformity of the wetting effect; S104, Exhaust and detection: Open the exhaust port of the liquid injection equipment to discharge the excess gas and residual electrolyte in the battery cell, and conduct visual inspection and performance testing on the battery cell to ensure that the wetting effect and performance of the battery cell meet the requirements.

3. The electrolyte infiltration method for optimizing cylindrical batteries according to claim 1, characterized in that, The steps S101 of vacuum pumping and S102 of high-pressure liquid injection are carried out in a gradient cyclic manner.

4. The electrolyte infiltration method for optimizing cylindrical batteries according to claim 1, characterized in that The specific steps of S200 are as follows: S201, Battery cell placement: After high-pressure and vacuum liquid injection, take out the battery cell from the liquid injection equipment and place it in a normal temperature environment for aging, ensuring that the battery cell is in a stable and safe position and avoiding external impact or vibration during the aging process; S202, Temperature control: Conduct aging in a constant normal temperature environment to ensure sufficient contact and interaction between the electrolyte and the electrode sheet; S203, Time control: Precisely control the aging time at normal temperature to enable sufficient physical and chemical interactions between the electrolyte and the electrode sheet, and promote the uniform distribution and penetration of the electrolyte; S204, Monitoring and recording: Regularly monitor the battery cell and record its state changes, including measuring the temperature, voltage, and time of the battery cell to ensure that the battery cell is in a safe and stable state during the aging process; S205, End inspection: When the aging time at normal temperature reaches the preset value, take out the battery cell from the aging environment and conduct visual inspection and performance testing, including checking for abnormal conditions such as leakage and deformation, and testing its voltage and capacity performance parameters to ensure that it can meet the requirements of subsequent processes after aging at normal temperature.

5. The electrolyte infiltration method for optimizing cylindrical batteries according to claim 4, characterized in that, During the aging process at normal temperature, precisely control the temperature in an environment of 25°C ± 2°C and control the standing time to be 10h - 12h.

6. The electrolyte infiltration method for optimizing cylindrical batteries according to claim 1, characterized in that, S400 places the battery in an environment of 35°C ± 2°C for 7h - 8h to improve the speed, time, and effect of the electrolyte entering the electrode sheet.

7. The electrolyte infiltration method for optimizing cylindrical batteries according to claim 1, characterized in that, The specific steps of S600 are as follows: S601, Environment preparation: Select a clean, dust-free, constant temperature, and constant humidity environment to place the battery cells; S602, Placement of battery cells: Place the battery cells smoothly, avoiding vibration, impact, or external pressure on the battery cells, ensuring sufficient space between the battery cells to avoid mutual contact or friction; S603, Standing time: Set the standing time according to the battery type and manufacturing process requirements to allow various chemical reactions and physical processes inside the battery to reach equilibrium and stability; S604, Follow-up processing: Conduct performance inspection on the standing battery. If it passes, proceed with subsequent packaging and testing steps. If the battery performance does not meet the requirements, further analysis and processing will be carried out.

Images