Electrode assembly, battery, and method of manufacturing electrode assembly

Abstract

The application discloses a kind of battery cell liquid injection device, liquid injection method and liquid injection system;Battery cell liquid injection device includes liquid injection container, electrolyte container, solvent gasification device and vacuum device;First prepare electrolyte solvent, gasification after using solvent gasification device is introduced into battery cell, and gas is replaced to battery cell, and air is replaced, and by vacuumizing, so that battery cell keeps low pressure vacuum air environment;The prepared electrolyte solution is injected into battery cell, and vacuumizing is closed, and the liquid injection pressure of electrolyte solution makes that electrolyte solution fills in battery cell, after liquid injection, partial small amount of bubble in battery cell liquefies in electrolyte solution after pressure rise and temperature change, and high-quality liquid injection of battery cell is completed.The application avoids the problem that gas-liquid contact cannot be exhausted due to surface tension, so that the quality of battery cell liquid injection is greatly improved, thereby improving the overall performance and quality of battery product.

Description

Technical Field

[0001] This invention belongs to the field of battery manufacturing and relates to a cell liquid injection technology, specifically a cell liquid injection device, liquid injection method and liquid injection system. Background Technology

[0002] The electrolyte filling process is a crucial step in battery manufacturing, determining the electrolyte distribution within the cell and consequently affecting battery performance and lifespan. The electrolyte filling process has evolved from basic initial filling methods to modern high-precision, automated filling systems. Nevertheless, the electrolyte filling process still faces a series of challenges and problems, primarily focusing on optimizing electrolyte distribution and eliminating air bubbles.

[0003] Uniform electrolyte distribution is fundamental to ensuring battery performance. It needs to cover every corner of the cell to allow ions to flow freely, thus enabling the battery's charging and discharging process. Uneven electrolyte distribution can lead to increased internal resistance, reduced capacity, and shortened lifespan. Furthermore, traditional electrolyte filling processes often fail to completely eliminate air bubbles within the cell, which not only hinders adequate electrolyte filling but may also further affect the battery's internal resistance and capacity.

[0004] Current injection technologies mainly include the following: (1) Gravity injection method: The electrolyte is injected into the cell from top to bottom using gravity.

[0005] (2) Pressure injection method: Applying pressure to inject electrolyte into the cell can increase the injection speed.

[0006] (3) Vacuum injection method: Create a vacuum environment to reduce the generation of bubbles and promote the electrolyte to be more evenly distributed in the cell.

[0007] (4) Ultrasonic injection method: Ultrasonic vibration is used to promote the rapid penetration of electrolyte into the battery cell, while also helping to remove air bubbles.

[0008] (5) Microdroplet injection method: By controlling the size of the microdroplets and the injection speed, the microdroplet injection method can achieve more precise electrolyte control to ensure the uniform distribution of electrolyte.

[0009] (6) Pre-electrolyte cell method: Pre-electrolyte cell is a method in which the electrolyte is introduced into the cell during the cell manufacturing process. This method can simplify the electrolyte injection process, but may limit the flexibility of cell design.

[0010] Existing electrolyte injection technology has some obvious drawbacks and limitations, mainly in the following aspects: (1) Uneven distribution of electrolyte: Existing electrolyte injection technologies, such as gravity injection and pressure injection, cannot achieve uniform distribution of electrolyte within the battery cell. Uneven electrolyte distribution hinders ion transport within the battery, thus affecting charge transfer efficiency and energy storage capacity. This uneven distribution is particularly pronounced in high-capacity and high-energy-density batteries, potentially leading to increased internal resistance, reduced capacity, and shortened lifespan.

[0011] (2) Difficulty in removing air bubbles: Traditional electrolyte injection techniques often generate air bubbles during the process. These bubbles can hinder further electrolyte distribution and create "dead zones" inside the battery, areas where effective ion transport is impossible. The presence of bubbles not only affects electrolyte distribution but can also lead to decreased battery performance and shortened lifespan. While vacuum injection techniques can reduce bubble generation, a perfect vacuum cannot be achieved within the battery, leaving some residual bubbles that still impact battery performance.

[0012] To overcome these difficulties, engineers have developed various advanced electrolyte injection technologies and equipment. For example, vacuum electrolyte injection technology minimizes bubble formation by creating a vacuum environment, thereby promoting uniform electrolyte distribution. However, these technologies can only reduce bubble formation, not eliminate it. Therefore, controlling electrolyte injection and effectively removing bubbles has become a key technical challenge that battery manufacturers are striving to solve. This work is of great significance for improving battery performance and extending battery life, and is a crucial step in the battery manufacturing process, directly impacting battery product quality and market competitiveness. Summary of the Invention

[0013] The purpose of this invention is to address the technical challenge of increasing electrolyte injection difficulty as battery capacity increases. This invention proposes a method and apparatus for electrolyte injection into battery cells, which utilizes the phase change characteristics of electrolyte solvents to eliminate the surface tension of air in pores, expel residual air, and improve the electrolyte injection effect.

[0014] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows: On one hand, the present invention provides a method for electrolyte injection into a battery cell, which uses a vaporizable solvent as the electrolyte solvent to prepare the electrolyte, including the following steps: Prepare the electrolyte solvent, vaporize it and introduce it into the battery cell. Then, purge and replace the air in the battery cell with gas and maintain a low-pressure vacuum environment inside the battery cell by drawing a vacuum. The prepared electrolyte solution is injected into the battery cell, and the vacuum is turned off. The electrolyte solution fills the battery cell with the injection pressure. After injection, a small number of air bubbles in the battery cell liquefy in the electrolyte solution as the pressure increases (which may be accompanied by a decrease in temperature), thus completing the high-quality electrolyte injection of the battery cell.

[0015] This technical solution is mainly based on overcoming the liquid injection obstacle caused by the surface tension between the gas and liquid phases.

[0016] In existing electrolyte injection methods, the presence of air or other gases (even with vacuum, a small amount of air remains) creates surface tension when the electrolyte comes into contact with air or other inert gases, making it difficult for the electrolyte to penetrate the air-occupied pores of the battery cell. This invention creatively combines vacuum injection and pressure injection. Vacuuming removes most of the gas, and gas displacement removes the air, leaving only solvent gas. During this process, a vacuum is maintained to preserve the gaseous environment. Before electrolyte injection, the vacuum device is shut off. During injection, the electrolyte rapidly enters the battery cell due to the injection pressure. As injection progresses, the space inside the battery cell is gradually compressed, increasing the pressure. The gaseous solvent is compressed (and may condense simultaneously) and enters the electrolyte. Because the pressure is low before injection, and the volume change after condensation is large, the amount of solvent entering the electrolyte is actually very small, and its impact on the electrolyte concentration is negligible. In this invention, during injection, the main components of the gas and liquid phases are the same, and the gas phase can be converted into the liquid phase, thereby eliminating the surface tension that hinders injection. By adjusting the pressure and temperature of the cell environment, the input gas is converted into a liquid state (or dissolved in the electrolyte), thereby ensuring that the electrolyte can fill all the gaps in the cell without obstruction, ultimately improving battery performance.

[0017] Furthermore, the electrolyte injection is carried out in an injection container, and a vacuum device is connected to the top of the injection container to create a vacuum. Both the gaseous electrolyte solvent and the electrolyte are injected from the bottom of the injection container. This invention can be achieved by simply modifying existing injection containers by adding a main gas inlet at the bottom, resulting in low equipment modification costs.

[0018] Furthermore, before electrolyte injection, temperature and pressure are adjusted to ensure the electrolyte solvent gas inside the cell is in a saturated or superheated state. Due to its low density, the gas phase inside the cell can liquefy rapidly during subsequent electrolyte injection.

[0019] Furthermore, during the gas purging and replacement of the battery cells, the minimum purging time is determined by conducting quality tests on the final electrolyte-filled cell products. Generally, for batteries in existing technology, a purging time of 1-5 minutes is sufficient.

[0020] Furthermore, during purging, replacement, and electrolyte injection, the cell temperature should not exceed the maximum operating temperature of the electrolyte, generally not exceeding 80℃.

[0021] Furthermore, the gaseous waste gas that has been vacuumed away is condensed and recycled by a condensation recovery device to remove the electrolyte solvent.

[0022] Furthermore, when the cell is a lithium-ion battery, the electrolyte consists of lithium salt, solvent, and additives.

[0023] Furthermore, the solvent may include any one or more of polycarbonate, ethylene carbonate, dimethyl carbonate, diethyl carbonate, methyl ethyl carbonate, carboxylic acid ester, sulfite ester, and fluorinated solution.

[0024] Lithium salts include conventional lithium salts: lithium iron hexafluorophosphate (LiPF6), lithium tetrafluoroborate (LiBF4), and lithium difluorosulfonylimide (LiFSI).

[0025] The additives mainly include: film-forming additives, overcharge protection additives, high and low temperature additives, flame retardant additives, and rate-dependent additives.

[0026] On the other hand, the present invention provides a battery cell liquid injection device for a battery cell liquid injection method, comprising: The liquid injection container is used to hold the battery cells to be injected with liquid. It can withstand negative pressure and has a temperature control function. An electrolyte container is connected to the bottom of an injection container via an electrolyte pressurizing device. It is used to store the prepared electrolyte and inject the electrolyte into the bottom of the injection container after pressurizing it through the pressurizing device. The solvent vaporization device is connected to the bottom of the injection container via a pipeline, and is used to vaporize the electrolyte solvent and inject it from the bottom of the injection container; The vacuum device is connected to the top of the liquid injection container via a pipeline and is used to evacuate the liquid injection container to control the ambient pressure of the battery cell.

[0027] Furthermore, the solvent vaporization device can vaporize the electrolyte solvent, then heat it again to form a superheated gaseous solvent, which is then injected into the injection container.

[0028] Furthermore, the solvent vaporization device includes an evaporation device, an evaporation container, a heater, and a first control valve. The evaporation device heats the evaporation container. The heating method of the evaporation device can be electric heating, steam heating, microwave heating, etc., and the specific method is not limited, with the optimal method being the one that can control the heating power.

[0029] Optimally, the evaporation container is a spherical container with a bottle mouth and a sealing cap at the top. The sealing cap is equipped with a pressure measuring device (pressure gauge) and a temperature measuring device (temperature gauge) that extend into the evaporation container to measure the evaporation temperature and pressure, respectively. A steam pipe is also provided on the sealing cap, and a heater for secondary heating is installed on the steam pipe to further increase the temperature of the gaseous solvent, making it a superheated gas and preventing condensation in the pipe and during purging. A first control valve is also installed on the steam pipe downstream of the heater to control the flow rate of the gaseous solvent during purging.

[0030] Furthermore, the electrolyte pressurization device is a booster pump (such as a centrifugal pump, plunger pump, or other fluid transport equipment), and the outlet of the booster pump is equipped with a second control valve for controlling the injection flow rate.

[0031] Furthermore, the vacuum device is a vacuum pump, the inlet of which is connected to the outlet at the top of the injection container via a pipe, and a third control valve for controlling the pressure inside the injection container is installed on the pipe. A condensation recovery device is installed at the outlet of the vacuum pump.

[0032] The condensation recovery device includes a condensation container, a cooling device, and an adsorption filtration device. The vacuum pump outlet is connected to the condensation container through a pipeline, and the gas containing gaseous solvent is introduced into the condensation container. The cooling device cools the condensation container, causing the solvent in the gas to condense into a liquid phase for recovery. An outlet is set at the top of the condensation container, which is connected to the adsorption filtration device through a pipeline. The remaining gas is discharged into the atmosphere after the adsorption filtration device adsorbs the small amount of solvent that has not had time to condense, thus achieving exhaust gas treatment.

[0033] Even better, the inlet pipe of the condenser is inserted below the liquid level to improve condensation efficiency.

[0034] The present invention also provides a battery cell liquid injection system, which adds a controller to the above-mentioned battery cell liquid injection device, and connects each device to the controller. The controller has a built-in program for executing the above-mentioned battery cell liquid injection method.

[0035] Compared with the prior art, the beneficial effects of the technical solution of the present invention include: (1) Improved electrolyte distribution: This technical solution can effectively overcome the surface tension barrier between the gas and liquid phases, allowing the electrolyte to enter all the gaps in the cell without obstruction. This will ensure the uniform distribution of the electrolyte in the cell, thereby reducing the internal resistance of the battery, increasing the battery capacity, and extending the battery life.

[0036] (2) Improved electrolyte injection efficiency: This solution optimizes each stage of the electrolyte injection process, including the vaporization of the electrolyte solvent, the adjustment of gaseous solvent parameters, and the injection of electrolyte, making the entire electrolyte injection process more efficient and controllable. This not only shortens the battery production cycle but also helps to reduce production costs.

[0037] (3) Achieving solvent recycling: In this scheme, the gaseous solvent extracted by the vacuum pump can be cooled and liquefied and recycled, which will reduce material consumption, reduce production costs, and help protect the environment.

[0038] (4) Enhancing the quality and market competitiveness of battery products: By improving electrolyte distribution and increasing injection efficiency, this solution helps to improve the overall performance and quality of battery products. This will make battery products more competitive in the market and provide battery manufacturers with an important technological advantage.

[0039] (5) Real-time monitoring and analysis: Through the application of pressure and temperature testing devices and flow meters, this solution allows for real-time monitoring and analysis of various parameters throughout the injection process. This will provide strong data support for optimizing the injection process, adjusting equipment parameters, and improving production processes.

[0040] (6) Expanding the application scope of electrolyte injection technology: This solution provides a novel electrolyte injection method, which may provide solutions to other technical problems in the field of battery manufacturing, and expands the application scope and research direction of electrolyte injection technology. Attached Figure Description

[0041] Figure 1 This is a schematic diagram of the cell liquid injection device in an embodiment of the present invention.

[0042] 100-Liquid injection container, 200-Electrolyte container, 210-Pressure booster, 220-Second control valve, 230-Flow meter, 300-Solvent vaporization device, 310-Evaporation device, 320-Evaporation container, 330-Heater, 340-First control valve, 350-Pressure measuring device, 360-Temperature measuring device, 400-Vacuum device, 410-Third control valve, 500-Condensation recovery device, 510-Condensation container, 520-Cooling device, 530-Adsorption filtration device, 600-Battery cell, 700-Electrolyte, 800-Electrolyte solvent, 900-Recovery liquid. Detailed Implementation

[0043] The embodiments of the present invention will be described in further detail below with reference to the accompanying drawings and examples. The following examples are for illustrative purposes only and should not be construed as limiting the scope of the invention.

[0044] In the description of this invention, it should be noted that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0045] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "connected" and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0046] like Figure 1 As shown, the present invention provides a battery cell liquid injection device for a battery cell liquid injection method, comprising: The liquid injection container 100 is used to hold the battery cell 600 to be injected with liquid. It can withstand negative pressure and has a temperature control function. The electrolyte container 200 is connected to the bottom of the injection container 100 via the electrolyte pressurization device 210. It is used to store the prepared electrolyte and inject the electrolyte into the bottom of the injection container 100 after pressurization by the pressurization device 210. The solvent vaporization device 300 is connected to the bottom of the liquid injection container 100 through a pipeline, and is used to vaporize the electrolyte solvent and inject it from the bottom of the liquid injection container 100. The vacuum device 400 is connected to the top of the liquid injection container 100 through a pipeline and is used to evacuate the liquid injection container 100 to control the ambient pressure of the battery cell 600.

[0047] like Figure 1 As shown, the solvent vaporization device 300 includes an evaporation device 310, an evaporation container 320, a heater 330, and a first control valve 340. The evaporation device 310 heats the evaporation container 320. The heating method of the evaporation device 310 can be electric heating, steam heating, microwave heating, etc. The specific method is not limited, but the method that can control the heating power is optimal.

[0048] In a preferred embodiment, the evaporation container 320 is a spherical container with a bottle mouth and a sealing cap at the top. The sealing cap is equipped with a pressure measuring device 350 (pressure gauge) and a temperature measuring device 360 ​​(thermometer) that extend into the evaporation container 320 to measure the evaporation temperature and pressure, respectively. A steam pipe is also provided on the sealing cap, and a heater 330 for secondary heating is installed on the steam pipe to further increase the temperature of the gaseous solvent, making it a superheated gas and preventing condensation in the pipe and during purging. A first control valve 340 is also provided on the steam pipe downstream of the heater 330 to control the flow rate of the gaseous solvent during purging.

[0049] As a preferred embodiment, a flow meter (not shown in the figure) can also be installed on the outlet pipe of the evaporator 320 (the pipe near the first control valve 340) to adjust the purge gas flow rate.

[0050] For example, the electrolyte pressurization device 210 is a booster pump, and the outlet of the booster pump is equipped with a second control valve 220 for controlling the injection flow rate. It should be noted that a flow meter 230 is installed at the outlet of the booster pump to monitor the injection flow rate.

[0051] For example, the vacuum device 400 is a vacuum pump. The inlet of the vacuum pump is connected to the outlet at the top of the liquid injection container 100 through a pipe. A third control valve 410 for controlling the pressure inside the liquid injection container 100 is provided on the pipe. A condensation recovery device is provided at the outlet of the vacuum pump.

[0052] For example, the condensation recovery device 500 includes a condensation container 510, a cooling device 520, and an adsorption filter 530. The vacuum pump outlet is connected to the condensation container 510 through a pipe, and the gas containing gaseous solvent is introduced into the condensation container 510. The cooling device 520 cools the condensation container 510, so that the solvent in the gas condenses into liquid phase for recovery. An outlet is provided at the top of the condensation container 510, which is connected to the adsorption filter 530 through a pipe. The remaining gas is discharged into the atmosphere after the adsorption filter 530 adsorbs a small amount of solvent that has not had time to condense, thus achieving exhaust gas treatment.

[0053] In a preferred embodiment, the inlet pipe of the condenser 510 is inserted below the liquid surface to improve condensation efficiency.

[0054] The following explanation uses ethylene carbonate (EC) as a solvent, lithium iron hexafluorophosphate as a solute, and other commonly used additives to prepare an electrolyte for lithium-ion batteries.

[0055] Ethylene carbonate is a widely used organic solvent and a component of high-capacity electrolytes in lithium and lithium-ion batteries. Based on the gas-liquid phase transition characteristics of ethylene carbonate, it is suitable for use at temperatures between 36.33°C and 33.2°C. With 529.85 The corresponding saturation pressure range is 0.0112657 kPa to 6949.67 kPa. Within this temperature range, when the pressure is below the saturation pressure, ethylene carbonate will begin to vaporize (boil). By adjusting the temperature of the electrolyte solvent in the evaporation vessel 320 and the operating pressure of the vacuum pump, a suitable set of operating parameters can be found between 36.332℃ and 529.85℃, allowing ethylene carbonate to operate under stable vaporization conditions. Higher operating temperatures correspond to higher vaporization pressures, which can be compensated for by increasing the temperature. Under high vacuum conditions, the density of gaseous ethylene carbonate is very low, less than one-thousandth the density of liquid ethylene carbonate of the same volume, therefore the change in electrolyte concentration caused by the reliquefied solvent within the cell can be ignored.

[0056] An example of operation using ethylene carbonate as the working fluid is as follows: S1. Preparation stage: Close the first control valve 340 and the second control valve 220, open the third control valve 410, and start the vacuum pump to remove most of the air from the injection container 100. This step provides a vacuum environment for the subsequent ethylene carbonate vaporization operation.

[0057] S2. Solvent Vaporization: Next, the solvent vaporization stage begins. In this stage, the electrolyte solvent 800 in the evaporation container 320 is heated by the evaporation device 310 to approximately 60°C, which is within its vaporization temperature range. The first control valve 340 is opened, and the vacuum pump operates to ensure that the pressure is below the saturation pressure at 60°C, thus achieving stable vaporization of the ethylene carbonate. This process is monitored in real time by pressure and temperature testing devices.

[0058] S3. Gaseous solvent parameter adjustment: Since ethylene carbonate remains saturated after vaporization, heater 330 is used to further heat it into superheated steam, adjusting its superheat and raising the temperature to 75°C. This step ensures that ethylene carbonate reaches ideal injection conditions, avoiding the problem of re-liquefaction during purging in cell 600.

[0059] S4. Expel air: Introduce the adjusted gaseous ethylene carbonate into the injection container 100, and precisely purge different locations to remove residual air according to the structure of the container and the battery cell. Generally, purge for 1-5 minutes. By setting different purging durations and measuring parameters such as the battery weight after injection, the appropriate purging time can be determined.

[0060] S5. Electrolyte Injection: Close the first control valve 340, the third control valve 410, and the vacuum pump, and open the second control valve 220. An electrolyte solution prepared with ethylene carbonate as the solvent, lithium iron hexafluorophosphate as the solute, and other additives is stored in the electrolyte container 200. A pressurization device 210 (booster pump) pressurizes the electrolyte solution 700 in the electrolyte container 200 and injects it into the injection container 100. The booster pump allows for fine-tuning of the injection speed and pressure, and a flow meter provides real-time monitoring. This restores the internal pressure of the battery cell 600 to atmospheric pressure, causing the remaining ethylene carbonate to reliquefy, and the electrolyte completely fills the internal space of the battery cell 600.

[0061] The above process not only considers the specific physical and chemical properties of ethylene carbonate, but also introduces multiple control mechanisms to improve the accuracy and efficiency of the electrolyte injection process. This customized approach provides a more refined and controllable electrolyte injection solution for the battery manufacturing industry.

[0062] When air is expelled, the gas expelled by the vacuum pump carries a large amount of ethylene carbonate. Direct emission of this gas not only wastes raw materials but also pollutes the environment. Therefore, it can be recycled. The gas extracted by the vacuum pump is introduced into a condenser container 510, which is then cooled by a cooling device 520. The condenser container 510 is liquefied by cooling, thus achieving recycling of the gaseous ethylene carbonate. Any excess gas can be treated by an adsorption filter device 530 before being discharged; this achieves raw material reuse without pollution emissions.

[0063] To achieve automated liquid injection, this invention also provides a cell liquid injection system. A controller is added to the aforementioned cell liquid injection device, and all devices are connected to the controller. The controller has a built-in program for executing the aforementioned cell liquid injection method. Specifically, the vacuum device 400, condensation recovery device 500, solvent vaporization device 300, pressurization device 210, second control valve 220, flow meter, first control valve 340, second control valve 220, and third control valve 410 are connected to the controller. After selecting their optimal parameters, the liquid injection is automated by sequentially executing these parameters in the controller's control box.

[0064] It should be noted that the solvent vaporization device 300 described above is only an example; in practice, any device capable of stably generating gaseous solvents can be used.

[0065] The above embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Although the invention has been described in detail with reference to the embodiments, those skilled in the art should understand that various combinations, modifications, or equivalent substitutions of the technical solutions of the invention do not depart from the spirit and scope of the invention and should be covered within the scope of the claims of the invention.

Claims

1. A method for injecting electrolyte into a battery cell, wherein a vaporizable solvent is used as the electrolyte solvent to prepare the electrolyte, characterized in that, Includes the following steps: Prepare the electrolyte solvent, vaporize it and introduce it into the battery cell. Then, purge and replace the air in the battery cell with gas and maintain a low-pressure vacuum environment inside the battery cell by drawing a vacuum. The prepared electrolyte solution is injected into the battery cell, and the vacuum is turned off. The electrolyte solution is injected to fill the battery cell. After injection, a small number of air bubbles in the battery cell liquefy in the electrolyte solution as the pressure increases, thus completing the high-quality electrolyte injection of the battery cell.

2. The cell electrolyte injection method according to claim 1, characterized in that, Electrolyte injection is carried out in an injection container. A vacuum device is connected to the top of the injection container to create a vacuum. Both the gaseous electrolyte solvent and the electrolyte are injected from the bottom of the injection container.

3. The cell electrolyte injection method according to claim 1, characterized in that, Before electrolyte injection, temperature and pressure are adjusted to ensure that the electrolyte solvent gas inside the cell is in a saturated or overheated state.

4. The cell electrolyte injection method according to claim 1, characterized in that, When performing gas purging and replacement on the battery cells, the shortest purging time is determined by conducting quality tests on the final electrolyte-filled battery cell products.

5. The cell electrolyte injection method according to claim 1, characterized in that, During purging, replacement, and electrolyte injection, the cell temperature shall not exceed the maximum operating temperature of the electrolyte.

6. The cell electrolyte injection method according to claim 1, characterized in that, The gaseous waste gas that is vacuumed away is condensed and recycled by a condensation recovery device to remove the electrolyte solvent.

7. The cell electrolyte injection method according to claim 1, characterized in that, The electrolyte solvent is vaporized by adjusting the temperature and pressure. The electrolyte solvent is any one or more of polycarbonate, ethylene carbonate, dimethyl carbonate, diethyl carbonate, methyl ethyl carbonate, carboxylic acid ester, sulfite ester, and fluorinated solution.

8. A cell electrolyte injection device for the cell electrolyte injection method according to any one of claims 1-7, characterized in that, include The liquid injection container is used to hold the battery cells to be injected with liquid. It can withstand negative pressure and has a temperature control function. An electrolyte container is connected to the bottom of an injection container via an electrolyte pressurizing device. It is used to store the prepared electrolyte and inject the electrolyte into the bottom of the injection container after pressurizing it through the pressurizing device. The solvent vaporization device is connected to the bottom of the injection container via a pipeline. It is used to vaporize the electrolyte solvent and then inject it from the bottom of the injection container after further temperature regulation. The vacuum device is connected to the top of the liquid injection container via a pipeline and is used to evacuate the liquid injection container to control the ambient pressure of the battery cell.

9. The cell electrolyte injection device according to claim 8, characterized in that, The vacuum device is a vacuum pump, and the outlet of the vacuum pump is equipped with a condensation recovery device.

10. A cell electrolyte injection system, characterized in that, It includes a controller and a cell liquid injection device as described in claim 8 or 9, wherein the controller stores a program for performing the cell liquid injection method as described in any one of claims 1-7.

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