Battery cell manufacturing apparatus and manufacturing method, battery cell
By designing a battery cell preparation device and using a gas collecting cylinder and piston system to monitor the gas production of the cell, the problem of incomplete gas production during the cell formation process was solved, and precise control of the gas production of the cell and improvement of the quality of the battery cell were achieved.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- ZHEJIANG JINKO ENERGY STORAGE CO LTD
- Filing Date
- 2026-05-07
- Publication Date
- 2026-06-05
AI Technical Summary
In existing technologies, the amount of gas generated during the cell formation process cannot be effectively monitored and controlled, resulting in incomplete degassing of individual cells and easy generation of interface defects such as brown spots.
Design a battery cell preparation device, including a gas collecting cylinder, a piston, a control part, a fixing part, and an elastic structure. By moving the piston in the gas collecting cylinder, combined with an indicator part and a drive structure, the amount of gas generated during the cell formation or aging process can be monitored and controlled in real time.
It enables precise monitoring and control of gas production in battery cells, ensuring that gas production meets requirements during formation and aging processes, avoiding poor cell performance, and improving the production quality of individual battery cells.
Smart Images
Figure CN122158739A_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of battery technology, and in particular to a battery cell preparation apparatus and preparation method, and a battery cell. Background Technology
[0002] Lithium-ion battery cell formation is a crucial step in battery cell production, directly impacting interface formation and resulting in more gas generation compared to normal cells. However, due to variations in manufacturing processes, complete degassing cannot be guaranteed for individual cells, leading to the formation of brown spots that are difficult to remove completely. Summary of the Invention
[0003] Therefore, it is necessary to propose a battery cell preparation apparatus capable of confirming whether the gas production of the cell is abnormal. A battery cell preparation method is also proposed. A battery cell is further proposed.
[0004] In a first aspect, this application proposes a battery cell manufacturing apparatus, comprising: a gas collecting cylinder for collecting gas generated during the cell formation or aging process, the gas collecting cylinder having an inlet and an outlet, the inlet being connected to the electrolyte injection port of the battery cell, and a plurality of indicator portions provided on the cylinder wall along the axial direction of the gas collecting cylinder, the indicator portions indicating the theoretical gas generation during the cell formation or aging process; a piston disposed inside the gas collecting cylinder and slidably connected to the gas collecting cylinder, the piston moving axially to different indicator portions indicating different amounts of gas collected in the gas collecting cylinder; a control portion disposed outside the gas collecting cylinder and throttlely connected to the piston; a fixing portion disposed outside the gas collecting cylinder; and an elastic structure located between the control portion and the fixing portion, for providing resistance when the piston moves axially away from the inlet.
[0005] In some embodiments, the air inlet is located on the axial end face of the air collecting cylinder.
[0006] In some embodiments, the plurality of indicator portions are arranged in a straight line in the axial direction of the gas collecting cylinder, away from the air inlet.
[0007] In some embodiments, the indicator includes scale values.
[0008] In some embodiments, the gas collecting cylinder is entirely transparent, or the cylinder wall of the gas collecting cylinder is provided with an observation window, and multiple indicator parts are located inside the observation window.
[0009] In some embodiments, a drive structure is also included, which is drively connected to the control unit. The drive structure is configured to provide multiple fixed driving forces, which are mapped to multiple indicators. Different fixed driving forces are used to make the piston overcome the resistance of the elastic structure and move to the corresponding indicator when the actual gas production is consistent with the theoretical gas production.
[0010] In some embodiments, an exhaust pipe with an exhaust valve is connected to the exhaust port.
[0011] In some embodiments, the control unit is suspended below the fixed unit by the elastic structure.
[0012] In a second aspect, this application proposes a method for preparing a battery cell, comprising: connecting the liquid injection port of the battery cell to the air inlet of a gas collecting cylinder containing a piston; during the battery cell formation or aging process, moving the piston to create a negative pressure in the gas collecting cylinder to collect the actual gas produced by the battery cell; and determining whether the actual gas production reaches the theoretical gas production based on whether the piston moves to the corresponding indicator on the gas collecting cylinder.
[0013] In some embodiments, the battery cell is a lithium-ion battery cell.
[0014] In some embodiments, during the cell formation or aging process, moving the piston to create a negative pressure within the gas collecting cylinder to collect the actual gas generated by the cell includes: applying a fixed driving force that is mapped to the indicator to the piston so that the piston moves against the resistance of the elastic structure.
[0015] In some embodiments, the piston is automatically driven using a drive structure.
[0016] In some embodiments, the process further includes: if the actual gas production collected during the formation process is less than the theoretical gas production, the formation process of the battery cell continues; if the actual gas production collected during the formation process is greater than or equal to the theoretical gas production, the formation process ends.
[0017] In some embodiments, the formation process includes constant current charging to raise the cell voltage from an initial voltage to a second voltage; during the cell formation or aging process, the piston is moved to create a negative pressure in the gas collecting cylinder to collect the actual gas produced by the cell; including: when the cell voltage is raised from an initial voltage to a first voltage by constant current charging, the piston is moved to create a negative pressure in the gas collecting cylinder; the battery cell preparation method further includes: if the actual gas production collected during the formation process is less than the theoretical gas production, the cell voltage is raised from an initial voltage to a second voltage by constant current charging, where the second voltage is greater than the first voltage.
[0018] In some embodiments, the battery cell preparation method further includes: if the actual gas production during the aging process is less than the theoretical gas production, the cell is subjected to formation treatment again; if the actual gas production during the aging process is greater than or equal to the theoretical gas production, the cell is subjected to full-charge aging treatment.
[0019] In some embodiments, before the battery cell is subjected to formation treatment or full-charge aging treatment again, the process further includes: venting through the vent.
[0020] In some embodiments, during the cell formation or aging process, the piston is moved to create a negative pressure in the gas collecting cylinder to collect the actual gas produced by the cell, including: between multiple formation processes, or between a formation process and a subsequent aging process, the piston is reset to its initial position.
[0021] In a third aspect, this application proposes a battery cell prepared by the aforementioned battery cell preparation method.
[0022] In this application, the actual gas production is determined to be equal to the theoretical gas production based on whether the piston moves to the corresponding indicator on the gas collecting cylinder. This allows for the determination of the difference between the actual gas production and the theoretical gas production at the current process stage, providing a basis for subsequent processing measures. Cells with insufficient actual gas production can continue formation processing, thereby avoiding the impact of insufficient gas production on the electrical performance of the cells. Attached Figure Description
[0023] Figure 1 This is a schematic diagram of the structure of a battery cell manufacturing apparatus and a battery cell assembly according to an embodiment of this application.
[0024] Figure 2 This is a schematic diagram of the system composition of a battery cell preparation apparatus according to an embodiment.
[0025] Figure 3 This is a schematic flowchart of a photovoltaic cell preparation method according to an embodiment of this application.
[0026] Figure 4 This is a flowchart illustrating the process of formation 2 to aging in a photovoltaic cell preparation method according to an embodiment of this application.
[0027] Figure label:
[0028] 1. Battery cell preparation device; 100. Gas monitoring device; 10. Gas collection cylinder; 110. Air inlet; 120. Exhaust outlet; 130. Indicator; 140. Exhaust valve; 150. Exhaust pipe; 20. Piston; 30. Control unit; 40. Fixing unit; 50. Elastic structure; 60. Drive structure; 200. Battery cell; 201. Liquid injection port; 300. Formation cabinet; 400. Workbench; 410. Base; 420. Support frame; 500. Aging cabinet; 600. Negative pressure system. Detailed Implementation
[0029] To make the above-mentioned objectives, features, and advantages of this application more apparent and understandable, the specific embodiments of this application are described in detail below with reference to the accompanying drawings. Many specific details are set forth in the following description to provide a thorough understanding of this application. However, this application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of this application. Therefore, this application is not limited to the specific embodiments disclosed below.
[0030] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein in the specification of this application is for the purpose of describing particular embodiments only and is not intended to be limiting of this application.
[0031] Spatial relation terms such as “below,” “under,” “below,” “under,” “above,” “above,” etc., are used herein to describe the relationship between one element or feature shown in the figure and other elements or features. It should be understood that, in addition to the orientation shown in the figure, spatial relation terms also include different orientations of the device in use and operation. For example, if the device in the figure is flipped, the element or feature described as “below,” “under,” or “below” will be oriented “above” the other element or feature. Therefore, the exemplary terms “below” and “under” can include both above and below orientations. Furthermore, the device may also include other orientations (e.g., rotated 90 degrees or other orientations), and the spatial descriptive terms used herein will be interpreted accordingly.
[0032] When used herein, the singular forms of “a,” “an,” and “the” may also include the plural forms unless the context clearly indicates otherwise. It should also be understood that the terms “comprising / including” or “having,” etc., specify the presence of the stated features, wholes, steps, operations, components, parts, or combinations thereof, but do not preclude the possibility of the presence or addition of one or more other features, wholes, steps, operations, components, parts, or combinations thereof. Meanwhile, in this specification, the term “and / or” includes any and all combinations of the associated listed items.
[0033] The battery cell described in this application refers to the final finished battery, the smallest unit of a power battery, and also an energy storage unit. The battery cell described in this application, however, refers to a semi-finished battery cell during the battery cell manufacturing process. The capacity of a battery cell is closely related to the cell formation process during manufacturing. Formation refers to the process after battery manufacturing, where the positive and negative electrode materials inside the battery are activated through specific charging and discharging methods to improve the overall performance of the battery. During this process, a series of complex electrochemical reactions occur, forming an SEI film and generating gas.
[0034] In the manufacturing process of battery cells, after the cells are produced, the capacity is typically determined through formation (charging and discharging of the cell), and performance stability is determined through aging. During both formation and aging, the cell releases gas, and the thoroughness of degassing directly affects interface formation. In this application, the gas production rate of the cell refers to the amount of gas produced by the cell during formation or aging.
[0035] Therefore, firstly, refer to Figure 1 This application provides a battery cell preparation apparatus 1, which is used to monitor the gas generation during the formation and aging processes.
[0036] The battery cell fabrication apparatus 1 includes a gas monitoring device 100, which comprises a gas collecting cylinder 10, a piston 20, a control unit 30, a fixing unit 40, and an elastic structure 50. The gas collecting cylinder 10 collects gases generated during the formation or aging process of the battery cell 200. The gas collecting cylinder 10 has an inlet 110 and an outlet 120. The inlet 110 communicates with the liquid injection port 201 of the battery cell 200. Multiple indicator sections 130 are provided on the cylinder wall along the axial direction of the gas collecting cylinder 10, indicating the theoretical gas generation during the formation or aging process of the battery cell 200. The piston 20 is disposed inside the gas collecting cylinder 10 and slidably connected to it. When the piston 20 moves axially to different indicator sections 130, it indicates that different amounts of gas have been collected in the gas collecting cylinder 10. The control unit 30 is disposed outside the gas collecting cylinder 10 and is throttle-connected to the piston 20. The fixing part 40 is provided on the outside of the air collecting cylinder 10. The elastic structure 50 is located between the control part 30 and the fixing part 40 to provide resistance when the piston 20 moves axially away from the air inlet 110.
[0037] The theoretical gas production of cell 200 refers to the amount of gas produced by a cell 200 that meets performance standards under ideal conditions during formation or aging treatment. The actual gas production of cell 200 refers to the amount of gas produced during the actual formation and aging treatment process. By comparing the theoretical and actual gas production, it is determined whether the capacity of cell 200 meets the requirements, thereby determining whether further formation or aging treatment is needed.
[0038] The gas collecting cylinder 10 is a device with an internal cavity. By connecting the air inlet 110 to the liquid injection port 201 of the battery cell 200, it can collect the actual gas production of the battery cell 200 during the formation or aging process. The exhaust port 120 is used to discharge the collected gas for future use. Multiple indicator sections 130 are provided on the side wall of the gas collecting cylinder 10. The indicator sections 130 are used to characterize the theoretical gas production during the formation or aging process of the battery cell 200. The indicator sections 130 can be determined, for example, by monitoring the gas production of a standard battery cell 200 with the required capacity. Multiple gas production occurs during the formation and aging process, and the multiple indicator sections 130 correspond to the theoretical gas production at different gas production stages.
[0039] When the process stage is formation, the actual gas production is the actual gas production of that formation, and the corresponding theoretical gas production is the theoretical gas production of that formation. When the process stage is aging, the actual gas production is the actual gas production of that aging stage, and the corresponding theoretical gas production is the theoretical gas production of that aging stage.
[0040] The piston 20 is connected to the control unit 30 outside the air collecting cylinder 10, and an elastic structure 50 is provided between the control unit 30 and the fixed part 40. By applying an external force to the control unit 30, the control unit 30 can overcome the resistance of the elastic structure 50 and move the piston 20 away from the air inlet 110 in the axial direction (hereinafter referred to as the axial direction) relative to the air collecting cylinder 10. When no external force is applied to the control unit 30, the position of the piston 20 under the action of the elastic structure 50 is called the initial position. The elastic structure 50 is, for example, a spring, a rubber rod, etc.
[0041] In this application, when the piston 20 moves to the indicator 130 in the gas collecting cylinder 10, the reference datum on the piston 20 is aligned radially with the indicator 130 in the gas collecting cylinder 10. At this time, any position of the piston 20 on the shaft can be used as the reference datum for determining the axial position of the piston 20. Optionally, such as... Figure 1 In this context, the reference datum can be the lower end face of the piston 20 among its two end faces in the axial direction. When the lower end face is aligned radially with an indicator 130 in the gas collecting cylinder 10, it indicates that the piston 20 has moved axially to the indicator 130.
[0042] The working principle of the battery cell manufacturing apparatus 1 of this application is as follows. For example, when it is necessary to monitor whether the actual gas production during the formation process meets the requirements, the air inlet 110 is connected to the liquid injection port 201 of the battery cell 200. After the battery cell 200 produces gas for a period of time, a set external force is applied, causing the control unit 30 to overcome the resistance of the elastic structure 50 and drive the piston 20 to move axially away from the air inlet 110 relative to the gas collecting cylinder 10. If the piston 20 can be pulled axially from its initial position to the corresponding indicator 130, it indicates that the actual gas production of the battery cell 200 is consistent with the theoretical gas production. If the actual gas production is less than the theoretical gas production, the piston 20 will not be able to be pulled to the corresponding indicator 130 under the negative pressure inside the battery cell 200. If the actual gas production is less than the theoretical gas production, the piston 20 will pass the corresponding indicator 130. In the above process, the magnitude of the applied external force is equal to the standard force. The standard force is a fixed driving force that needs to be applied when monitoring the standard cell 200, which enables the piston 20 to be pulled axially from its initial position to the position of the corresponding indicator 130.
[0043] Furthermore, the exhaust port 120 can be used to perform multiple actual gas production tests. Once a gas production test is completed, the gas in the gas collecting cylinder 10 can be discharged through the exhaust port 120, and then, under the action of the elastic structure 50, the piston 20 can return to its initial position. For example, the exhaust port 120 is located on the side wall of the gas collecting cylinder 10.
[0044] The battery cell preparation apparatus 1 of this application embodiment can be used to monitor gas production during the formation and aging processes. By observing whether the piston 20 moves axially to the corresponding indicator 130, the difference between the actual gas production and the theoretical gas production at the current process stage can be determined, providing a basis for taking subsequent processing measures. Subsequent processing measures include continued formation, continued aging, and waste classification.
[0045] refer to Figure 1 In some embodiments, the air inlet 110 is located on the axial end face of the air collecting cylinder 10. The air collecting cylinder 10 has an air inlet 110 on the lower end face of both axial end faces.
[0046] When the air inlet 110 is connected to the liquid injection port 201 of the battery cell 200, the gas generated by the battery cell 200 can quickly enter the gas collecting cylinder 10 axially after entering the air inlet 110, resulting in high collection efficiency of the gas collecting cylinder 10. Furthermore, by using the above method, when monitoring the actual gas production during the formation and aging processes, with the liquid injection port 201 of the battery cell 200 facing upwards, the air inlet 110 of the gas collecting cylinder 10 can be axially aligned with the liquid injection port 201 of the battery cell 200. The connection path between the liquid injection port 201 and the air inlet 110 is a straight line, which facilitates the design of the shortest connection path, thereby improving the efficiency and accuracy of the piston 20 during gas extraction and avoiding the impact on efficiency and accuracy due to an excessively long connection path.
[0047] Furthermore, along the axial direction of the air collecting cylinder 10, a plurality of indicator sections 130 are arranged in a straight line in a direction away from the air inlet 110. (Reference) Figure 1 Multiple indicator sections 130 are arranged in sequence to form an indicator area that can be observed in a concentrated manner, making it convenient for users to observe.
[0048] refer to Figure 1 , one In some embodiments, the indicator 130 includes scale values. In this application, the indicator 130 is configured to include scale values. The way the scale values are set facilitates observation of whether the piston 20 is radially aligned with a certain scale value, improving indication accuracy. Optionally, such as... Figure 1 In this context, the reference datum can be the lower end face of the piston 20 among its two end faces in the axial direction. When the lower end face is aligned with a certain scale value in the radial direction of the gas collecting cylinder 10, it indicates that the piston 20 has moved to the indicator 130 in the axial direction.
[0049] Furthermore, by setting the indicator 130 to include scale values, the user can not only know the axial position of the piston 20, but also simultaneously obtain the specific value of the actual gas production, or estimate the deviation between the actual and theoretical gas production. For example, when the piston 20 has not moved to the corresponding indicator 130, the deviation between the actual and theoretical gas production can be estimated based on the scale value difference between adjacent indicators 130 and the axial distance between the piston 20 and the corresponding indicator 130, providing more basis for taking subsequent processing measures. For example, if the actual gas production is insufficient, the battery cell 200 needs to continue formation processing. The magnitude of the deviation between the actual and theoretical gas production can be used to guide the improvement of the battery cell 200 manufacturing process.
[0050] Furthermore, a scale is provided between adjacent indicator sections 130. Through this scale, users can obtain relatively accurate information about the deviation between the actual gas production and the theoretical gas production, providing more accurate data support for taking subsequent processing measures.
[0051] refer to Figure 1In some embodiments, the gas collecting cylinder 10 is a transparent structure, or the cylinder wall of the gas collecting cylinder 10 is provided with an observation window, and multiple indicators 130 are located inside the observation window.
[0052] When the gas collecting cylinder 10 is a transparent structure, the user can observe the movement of the piston 20 within the cylinder 10 as a whole, and thus determine the axial position of the piston 20. When the cylinder wall of the gas collecting cylinder 10 is equipped with an observation window, multiple observation methods are provided. For example, if the piston 20 is not observed to enter the observation window area, it can be directly determined that the piston 20 has not moved to the corresponding indicator 130. If the piston 20 is observed to enter the observation window area, it can be further determined whether it has moved to the corresponding indicator 130.
[0053] refer to Figure 1 , one In some embodiments, the battery cell preparation apparatus 1 further includes a drive structure 60. The drive structure 60 is connected to the control unit 30 and is configured to provide multiple fixed driving forces. The multiple fixed driving forces are mapped to multiple indicator units 130. Different fixed driving forces are used to make the piston 20 overcome the resistance of the elastic structure 50 and move to the corresponding indicator unit 130 when the actual gas production is consistent with the theoretical gas production.
[0054] Optionally, the drive structure 60 is a servo motor system, which can directly reflect the load force through the motor current (torque). Optionally, the drive structure 60 is a pneumatic cylinder system, which can change the output force by controlling the air pressure through a proportional / pressure regulating valve, or adjust the force output range by using a combination of multiple cylinders.
[0055] Taking gas generation detection during the formation process as an example, if the actual gas generation of the cell 200 is consistent with the theoretical gas generation, when a corresponding fixed driving force is applied, the fixed driving force can pull the piston 20 axially from the initial position to the corresponding indicator 130. Conversely, if the actual gas generation of the cell 200 is inconsistent with the theoretical gas generation, the fixed driving force is insufficient to pull the piston 20 to the corresponding indicator 130, or it may exceed the indicated position.
[0056] The battery cell preparation apparatus 1 of this application, by setting a drive structure 60, can provide a precise fixed driving force, thereby enabling accurate inspection of the axial position of the piston 20.
[0057] refer to Figure 1In some embodiments, an exhaust pipe 150 with an exhaust valve 140 is connected to the exhaust port 120. The exhaust pipe 150 is used to connect to an exhaust gas treatment system. The exhaust valve 140 can close or open the exhaust port 120. When the exhaust port 120 is closed, the generated gas in the battery cell 200 can be collected, and the actual gas generation can be checked by pulling the piston 20. When the exhaust port 120 is open, the gas in the gas collection cylinder 10 is released, and then the actual gas generation of the battery cell 200 can be monitored again. The exhaust valve 140 is, for example, a solenoid valve.
[0058] refer to Figure 1 In some embodiments, the control unit 30 is suspended below the fixed unit 40 by an elastic structure 50.
[0059] In this application, the control unit 30 is suspended below the fixed part 40 via the elastic structure 50, so that the gas collecting cylinder 10 is also suspended below the fixed part 40. The fixed part 40 serves as both the mounting base for the gas collecting cylinder 10 and the mounting base for the elastic element, thereby simplifying the structure of the entire device. Furthermore, the way the gas collecting cylinder 10 is suspended below the fixed part 40 allows the air inlet 110 located on the lower end face of the gas collecting cylinder 10 to face downwards, thus enabling the battery cell 200 to be positioned directly below the gas collecting cylinder 10 with the liquid injection port 201 facing upwards. Consequently, the connection path between the liquid injection port 201 and the air inlet 110 is a straight line, which facilitates the design of the shortest connection path, thereby improving the efficiency and accuracy of the piston 20 during air extraction and avoiding the impact on efficiency and accuracy due to an excessively long path.
[0060] refer to Figure 2 In some embodiments, the battery cell preparation apparatus 1 of this application further includes a formation cabinet 300, a workbench 400 and an aging cabinet 500, wherein the workbench 400 is used to fix the battery cell 200 and install the gas monitoring device 100, and the workbench 400 can be placed in the formation cabinet 300 for formation or placed in the aging cabinet 500 for aging.
[0061] For example, the formation cabinet 300 is equipped with a charging management unit, a positive probe, and a negative probe (not shown). The positive probe is used to electrically connect with the positive terminal of the battery cell 200, and the negative probe is used to electrically connect with the positive terminal of the battery cell 200, thereby enabling the battery cell 200 to be charged and formed.
[0062] For example, the workbench 400 includes a base 410 and a support frame 420 disposed on the base 410. The base 410 is used to fix the battery cell 200. Optionally, the base 410 is provided with a snap-fit mechanism to fix the battery cell 200 placed on the tray to the base 410. The support frame 420 is used to mount the gas monitoring device 100. Optionally, a fixing part 40 is disposed on the support frame 420. The workbench 400 can be configured to mount multiple gas monitoring devices 100, which can simultaneously monitor the gas production of multiple battery cells 200.
[0063] For example, the aging cabinet 500 is equipped with shelves for placing the workbench 400.
[0064] Furthermore, the battery cell preparation apparatus 1 of this application also includes a negative pressure system 600, which is used to communicate with the exhaust port 120 of the gas monitoring device 100.
[0065] During formation, the workbench 400, the battery cell 200, and the gas monitoring device 100 are placed together in the formation cabinet 300. The positive probe is electrically connected to the positive terminal of the battery cell 200, and the negative probe is electrically connected to the positive terminal of the battery cell 200, so that the battery cell 200 can be charged and formed. At the same time, the gas monitoring device 100 monitors the gas production during the formation process.
[0066] When the formation process is complete and aging is required, first remove the workbench 400, battery cell 200 and gas monitoring device 100 from the formation cabinet 300, and then put the workbench 400, battery cell 200 and gas monitoring device 100 together into the aging cabinet 500 and let them stand.
[0067] In this application, the workbench 400 and the gas monitoring device 100 are placed together in the formation cabinet 300 or the aging cabinet 500, which can realize the formation or aging of the battery cell 200, and facilitate the switch from formation treatment to aging treatment.
[0068] A second aspect of this application also provides a method for preparing a single battery cell. (Reference) Figures 1 to 3 The battery cell preparation method includes the following steps.
[0069] S1. Connect the liquid injection port 201 of the battery cell 200 to the air inlet 110 of the gas collecting cylinder 10 which contains the piston 20.
[0070] S2. During the formation or aging process of the battery cell 200, the piston 20 is moved to create a negative pressure in the gas collecting cylinder 10 to collect the actual gas produced by the battery cell 200.
[0071] S3. Determine whether the actual gas production reaches the theoretical gas production based on whether the piston 20 moves to the corresponding indicator 130 on the gas collecting cylinder 10.
[0072] When it is necessary to monitor whether the actual gas production of the process meets the requirements, the air inlet 110 is connected to the liquid injection port 201 of the battery cell 200. After the battery cell 200 produces gas for a period of time, a set driving force is applied, causing the control unit 30 to overcome the resistance of the elastic structure 50 and drive the piston 20 to move axially away from the air inlet 110 relative to the gas collecting cylinder 10. If the piston 20 can be pulled axially from its initial position to the corresponding indicator 130, it indicates that the actual gas production of the battery cell 200 is consistent with the theoretical gas production. If the actual gas production is less than the theoretical gas production, the piston 20 will not be able to be pulled to the corresponding indicator 130 under the negative pressure inside the battery cell 200. If the actual gas production is less than the theoretical gas production, the piston 20 will pass the corresponding indicator 130.
[0073] In some embodiments, cell 200 is a lithium-filled cell. Lithium-filled cells differ from conventional non-lithium-filled cells in that they generate more gas and require thorough degassing. However, due to process differences, it cannot be guaranteed that cell 200 will be completely degassed. If degassing is insufficient during the lithium-filled cell formation stage, brown spots may appear, causing interface defects or other hidden dangers. Specifically, brown spots are caused by incomplete release of oxygen from the lithium-filling agent LFO, leaving oxygen residue at the interface. Incomplete secondary formation degassing will result in residual gas being released later.
[0074] This application, by employing the battery cell preparation method described herein, can determine whether the gas production of the lithium-ion battery cell meets the requirements, thereby laying the foundation for ensuring 100% degassing of the lithium-ion battery cell. For lithium-ion battery cells where the actual gas production during the formation stage does not meet the requirements, a second formation process can be performed to achieve full release of the lithium-ion agent gas.
[0075] In some embodiments, during the formation or aging process of the battery cell 200, S2 moves the piston 20 to create a negative pressure in the gas collecting cylinder 10 to collect the actual gas produced by the battery cell 200, including: S21, applying a fixed driving force that is mapped to the indicator 130 to the piston 20 so that the piston 20 moves against the resistance of the elastic structure 50.
[0076] Multiple fixed driving forces are mapped to multiple indicator sections 130. Different fixed driving forces are used to make the piston 20 overcome the resistance of the elastic structure 50 and move to the corresponding indicator section 130 when the actual gas production is consistent with the theoretical gas production.
[0077] During the battery cell manufacturing process, when monitoring whether the actual gas production at a certain process stage meets the requirements, a corresponding fixed driving force is applied to the piston 20, and then it is observed whether the piston 20 can be pulled axially from the initial position to the position of the corresponding indicator 130.
[0078] Furthermore, in some embodiments, the piston 20 is automatically driven using a drive structure 60.
[0079] The drive structure 60 can be configured to provide multiple constant driving forces, which are mapped to multiple indicators 130. Different constant driving forces are used to make the piston 20 overcome the resistance of the elastic structure 50 and move to the corresponding indicator 130 when the actual gas production is consistent with the theoretical gas production. By setting the drive structure 60, precise constant driving forces can be provided, thereby enabling accurate verification of the axial position of the piston 20.
[0080] In some embodiments, the battery cell preparation method of this application further includes:
[0081] S4. If the actual gas production collected during the formation process is less than the theoretical gas production, the formation process of the battery cell 200 shall continue.
[0082] S5. If the actual gas production collected during the formation process is greater than or equal to the theoretical gas production, the formation process ends.
[0083] Taking a lithium-ion battery cell as an example, the lithium-ion formation process is also the lithium-ion activation process. Controlling the actual amount of lithium added can achieve consistent capacity control for cell 200. During the formation process of cell 200, the actual gas production gradually increases over time; this formation process is the lithium-ion process. During the formation process, if the actual gas production is less than the theoretical gas production when it reaches the theoretical amount, it indicates that cell 200's gas production is incomplete, meaning the lithium-ion activation is incomplete. Therefore, the formation process continues, i.e., a second lithium-ion activation. This continues until the actual gas production of cell 200 equals or exceeds the theoretical gas production, indicating complete lithium-ion activation. At this point, cell 200 reaches the ideal capacity, and the formation process can be stopped.
[0084] Therefore, for lithium-ion cells, the cell preparation method of this application can determine whether the lithium-ion activation of cell 200 is complete, and if incomplete activation is determined, a secondary activation is performed to achieve full release of the lithium-ion agent gas. For non-lithium-ion cells, the method can also determine whether the gas production of the SEI film is qualified.
[0085] Furthermore, for lithium-ion battery cells, the lithium formation process can be divided into multiple charging processes with different voltage ranges, referred to as Formation 1, Formation 2, and so on. In this way, the actual gas production can be monitored during each formation process, thereby determining whether the gas production of that formation meets the requirements.
[0086] In some embodiments, the formation process includes constant current charging to raise the cell 200 from an initial voltage to a second voltage. Specifically, S2, during the formation or aging process of the cell 200, moving the piston 20 to create a negative pressure within the gas collecting cylinder 10 to collect the actual gas produced by the cell 200, includes: S22, when the constant current charging raises the cell 200 from the initial voltage to a first voltage, moving the piston 20 to create a negative pressure within the gas collecting cylinder 10. The battery cell preparation method of this application further includes: S6, if the actual gas production collected during the formation process is less than the theoretical gas production, constant current charging raises the cell 200 from the initial voltage to a second voltage, where the second voltage is greater than the first voltage.
[0087] The formation process includes constant current charging to raise the voltage of the battery cell 200 from an initial voltage to a second voltage. During the time it takes for the battery cell 200 to rise from its initial voltage to the first voltage, the actual gas production Q1 is denoted by time t1, and the corresponding theoretical gas production is a. Meanwhile, during the same time period, the actual gas production Q2 is denoted by time t2. Q1 is less than Q2, and t1 is less than t2.
[0088] In this application, the actual gas production Q1 within the time period t1 is collected in S2. Therefore, in S3, the actual gas production Q1 within a shorter time t1 is compared with the theoretical gas production a to determine whether the gas production of cell 200 meets the requirements. This eliminates the need to wait until the formation is complete to make the judgment, thereby improving the preparation efficiency.
[0089] In one example, cell 200 is a lithium-ion battery cell. The formation process includes, for example, constant current charging to raise cell 200 from 0.1V (initial voltage) to 3.4V (second voltage). This formation process can be, for example, a conventional SEI film formation stage. The actual gas produced is SEI film gas, mainly originating from the reduction and decomposition of the electrolyte and the reaction of trace impurities. The main gases produced are hydrogen (H2), carbon dioxide (CO2), and carbon monoxide (CO).
[0090] In this example, during the formation process, the actual gas production Q1 is collected when the constant current charging raises cell 200 from 0.1V (initial voltage) to 3.0V (first voltage). Then, Q1 is compared with the theoretical gas production when raising from 0.1V to 3.0V. If Q1 is less than the theoretical gas production, a second formation correction is performed. The second formation is as follows: constant current charging raises cell 200 from 0.1V (initial voltage) to 3.4V (second voltage). Specifically, cell 200 is reduced from 3.0V (first voltage) to 0.1V (initial voltage), and then the formation process restarts until cell 200 reaches 3.4V.
[0091] In this example, by comparing the actual gas production during a short period of time with the theoretical gas production during the formation process, it is possible to determine earlier whether the gas production of cell 200 meets the requirements. For cell 200 with insufficient actual gas production, secondary formation repair can be performed in a timely manner, and for cell 200 with excessive actual gas production, it can be screened out earlier.
[0092] In one example, cell 200 is a lithium-added cell. The formation process includes, for example, constant current charging to raise cell 200 from 3.4V (initial voltage) to 4.0V (second voltage). This formation process corresponds to the lithium-added activation of cell 200. This stage aims to ensure that the lithium-added agent is fully activated, releasing pre-stored lithium ions to compensate for irreversible capacity loss during the first charge-discharge process. The gas generation in cell 200 during this stage originates from the decomposition reaction of the added lithium-added agent. The gas generation differs depending on the lithium-added agent; for example, lithium iron ferrite (Li5FeO4) produces oxygen (O2), while lithium oxalate (Li2C2O4) decomposes to produce CO and CO2.
[0093] In this example, during the formation process, the actual gas production Q1 is collected when the constant current charging raises cell 200 from 3.4V (initial voltage) to 3.65V (first voltage). Then, Q1 is compared with the theoretical gas production when raising from 3.4V to 3.65V. If Q1 is less than the theoretical gas production a, the activation is considered insufficient, and a second formation activation can be performed between 3.4V and 4.0V. The second formation activation method is as follows: constant current charging raises cell 200 from 0.1V (initial voltage) to 4.0V (second voltage). Specifically, cell 200 is reduced from 3.65V (first voltage) to 3.4V (initial voltage), and then the formation process is restarted until cell 200 reaches 4.0V.
[0094] In some embodiments, the battery cell preparation method of this application further includes:
[0095] S7. If the actual gas production during the aging process is less than the theoretical gas production, the battery cell 200 shall be subjected to formation treatment again.
[0096] S8. If the actual gas production is greater than or equal to the theoretical gas production during the aging process, the battery cell 200 shall be subjected to full-charge aging treatment.
[0097] Cell 200 may also produce gas during the aging stage. For example, if some lithium replenishment is not completely formed, the residue may continue to react and produce gas during aging. For example, oxygen (O2) released during charging and discharging may affect the electrical performance of cell 200.
[0098] This application collects the actual gas production during aging, for example, 1 hour after the start of the aging process, and compares it with the theoretical gas production (b) at 1 hour of the aging stage. If the aging gas production is insufficient, the process is returned to the formation process to re-form the cell 200, avoiding any impact on the electrical performance of the cell 200. Optionally, the re-formation process involves re-activation and lithium replenishment formation. If the aging gas production is sufficient, a full-charge aging process is performed.
[0099] Furthermore, before performing the formation treatment or full-charge aging treatment on the battery cell 200 again, the process further includes: venting through the vent 120. In this application, the aging-generated gas is released through the vent 120 to prevent the oxygen in the aging-generated gas from participating in the internal reaction of the battery cell 200, thereby avoiding affecting the electrical performance of the battery cell 200. For example, releasing the aging-generated gas through the vent 120 achieves the purpose of venting and deoxygenation, preventing oxygen from reacting and being consumed again during the full-charge aging process, thus avoiding affecting the electrical performance of the battery cell 200.
[0100] In some embodiments, during the formation or aging process of the battery cell 200, the piston 20 is moved to create a negative pressure within the gas collecting cylinder 10 to collect the actual gas produced by the battery cell 200. This includes resetting the piston 20 to its initial position between multiple formation processes or between a formation process and a subsequent aging process. By resetting the piston 20, the accuracy of monitoring the actual gas production volume each time is ensured.
[0101] The following is an embodiment of the battery cell preparation method of this application:
[0102] refer to Figure 1 , Figure 4 The battery cell preparation method of this application can be utilized Figure 1 and Figure 2 The battery cell shown is manufactured as shown. Cell 200 is specifically a lithium-ion battery cell. Cell 200 is placed below the gas collecting cylinder 10, with the liquid injection port 201 of cell 200 connected to the air inlet 110 of the gas collecting cylinder 10. Gas production is monitored during the formation and aging process of cell 200, and subsequent treatment measures are taken.
[0103] For example, in this embodiment, the formation process of the battery cell 200 specifically includes three formation processes, which are defined as formation 1, formation 2 and formation 3 respectively.
[0104] Formation 1 involves constant current charging to raise the voltage of cell 200 from 0.1V to 3.4V. The constant current charging can be, for example, 0.1C-0.2C. This formation 1 corresponds to the conventional SEI film forming stage.
[0105] Formation 2 involves constant current charging to raise the voltage of cell 200 from 3.4V to 4.0V. The constant current charging rate can be, for example, 0.3C-0.5C. Formation 2 corresponds to the lithium replenishment activation of cell 200, which is defined here as the first lithium replenishment activation.
[0106] Formation 3 involves constant current charging to raise the voltage of cell 200 from 4.0V to 4.2V. The constant current charging rate can be, for example, 0.3C-0.5C. Formation 3 corresponds to the lithium replenishment activation of cell 200, which is defined here as the second lithium replenishment activation.
[0107] For example, in this embodiment, the aging process of the battery cell 200 specifically involves leaving it idle for 0.5-1 hour in a fully charged state. For example, 0.5 hours, 0.8 hours, or 1 hour.
[0108] In the first stage of the process, the actual gas production of cell 200 in the 0.1V-3.0V stage is checked by constant current charging. Cells 200 with abnormal interface are identified. Cells 200 with excessive actual gas production are screened out as unqualified products. Cells 200 with insufficient actual gas production are charged with 0.1C constant current until the voltage of cell 200 increases from 0.1V to 3.4V.
[0109] refer to Figure 4 This illustrates the process flow from the formation stage 2 to the aging stage.
[0110] In Formation 2, constant current charging is used to bring cell 200 from 3.4-3.65V, and the actual gas production during this stage is collected to confirm the initial activation of the lithium replenishment agent. Cells 200 with insufficient actual gas production are subjected to 0.3C constant current charging to raise their voltage from 3.4V to 4.0V for secondary activation. Cells 200 with actual gas production greater than or equal to theoretical gas production proceed to Formation 3.
[0111] In the third stage of formation, constant current charging is used to bring cell 200 from 4.0-4.05V, and the actual gas production during this stage is collected to confirm the second activation of the lithium replenishment agent. Cell 200 with insufficient actual gas production is charged with 0.3C constant current to raise the voltage from 4.0V to 4.2V for a second activation. Cell 200 with actual gas production greater than or equal to theoretical gas production enters the aging stage.
[0112] During aging: Collect the actual gas production after 1 hour of aging. If the actual gas production is greater than or equal to the theoretical gas production b after 1 hour of aging, continue aging at full charge. If the actual gas production is less than the theoretical gas production after 1 hour of aging, return to formation 3.
[0113] After aging is completed, the battery cells are tested for 200% capacity before being removed from the production line.
[0114] A third aspect of this application provides a battery cell prepared by the method of any of the above embodiments. During the preparation of the battery cell, by detecting the actual gas production, it can be determined whether the gas production of the cell 200 meets the requirements, thereby screening out unqualified products and ensuring that a battery cell with the required capacity and stable performance can be obtained.
[0115] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.
[0116] The above embodiments merely illustrate several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.
Claims
1. A battery cell preparation apparatus, characterized in that, include: A gas collecting cylinder is used to collect the gas generated during the battery cell formation or aging process. The gas collecting cylinder is provided with an air inlet and an air outlet. The air inlet is used to communicate with the liquid injection port of the battery cell. Multiple indicator parts are provided on the cylinder wall along the axial direction of the gas collecting cylinder. The indicator parts are used to indicate the theoretical gas generation during the battery cell formation or aging process. A piston is disposed inside the gas collecting cylinder and is slidably connected to the gas collecting cylinder. When the piston moves axially to different indicator sections, it indicates that different amounts of gas are collected in the gas collecting cylinder. The control unit is located outside the gas collecting cylinder and is connected to the piston drive. A fixing part is provided on the outside of the gas collecting cylinder; and An elastic structure, located between the control part and the fixed part, is used to provide resistance when the piston moves axially away from the air inlet.
2. The battery cell preparation apparatus according to claim 1, characterized in that, The air inlet is located on the axial end face of the air collecting cylinder.
3. The battery cell preparation apparatus according to claim 2, characterized in that, Along the axial direction of the gas collecting cylinder, the plurality of indicator sections are arranged in a straight line in sequence away from the air inlet.
4. The battery cell preparation apparatus according to claim 3, characterized in that, The indicator includes scale values.
5. The battery cell preparation apparatus according to claim 2, characterized in that, The gas collecting cylinder is entirely transparent, or the cylinder wall of the gas collecting cylinder is provided with an observation window, and multiple indicator parts are located inside the observation window.
6. The battery cell preparation apparatus according to claim 1, characterized in that, It also includes a drive structure, which is connected to the control unit. The drive structure is configured to provide multiple fixed driving forces, which are mapped to multiple indicators. Different fixed driving forces are used to make the piston overcome the resistance of the elastic structure and move to the corresponding indicator when the actual gas production is consistent with the theoretical gas production.
7. The battery cell preparation apparatus according to claim 1, characterized in that, An exhaust pipe with an exhaust valve is connected to the exhaust port.
8. The battery cell preparation apparatus according to claim 1, characterized in that, The control unit is suspended below the fixed part by the elastic structure.
9. A method for preparing a single battery cell, characterized in that, include: Connect the liquid injection port of the battery cell to the air inlet of the gas collecting cylinder, which has a piston inside. During the cell formation or aging process, the piston is moved to create a negative pressure in the gas collecting cylinder to collect the actual gas produced by the cell. and Whether the actual gas production reaches the theoretical gas production is determined by whether the piston moves to the corresponding indicator on the gas collecting cylinder.
10. The method for preparing a battery cell according to claim 9, characterized in that, The battery cell is a lithium-ion battery cell.
11. The method for preparing a battery cell according to claim 9, characterized in that, During the cell formation or aging process, the piston is moved to create a negative pressure within the gas collecting cylinder to collect the actual gas produced by the cell, including: A fixed driving force that is mapped to the indicator is applied to the piston so that the piston moves against the resistance of the elastic structure.
12. The method for preparing a battery cell according to claim 11, characterized in that, The piston is automatically driven by a drive structure.
13. The method for preparing a battery cell according to claim 9, characterized in that, Also includes: If the actual gas production collected during the formation process is less than the theoretical gas production, the cell will continue to undergo formation processing. If the actual gas production collected during the formation process is greater than or equal to the theoretical gas production, the formation process ends.
14. The method for preparing a battery cell according to claim 9, characterized in that, The formation process includes constant current charging to raise the cell voltage from an initial voltage to a second voltage; During the cell formation or aging process, the piston is moved to create a negative pressure in the gas collecting cylinder to collect the actual gas produced by the cell; including: when the cell is charged by constant current to raise the voltage from the initial voltage to the first voltage, the piston is moved to create a negative pressure in the gas collecting cylinder; The method for preparing the battery cell further includes: If the actual gas production collected during the formation process is less than the theoretical gas production, constant current charging will raise the cell voltage from the initial voltage to the second voltage, which is greater than the first voltage.
15. The method for preparing a battery cell according to claim 9, characterized in that, The method for preparing the battery cell further includes: If the actual gas production during the aging process is less than the theoretical gas production, the battery cell will undergo another formation process. If the actual gas production during the aging process is greater than or equal to the theoretical gas production, the battery cell will be subjected to full-charge aging treatment.
16. The method for preparing a battery cell according to claim 15, characterized in that, Before the battery cell undergoes further formation treatment or full-charge aging treatment, the process also includes: Exhaust is processed through the exhaust port.
17. The method for preparing a battery cell according to claim 9, characterized in that, During the cell formation or aging process, the piston is moved to create a negative pressure within the gas collecting cylinder to collect the actual gas produced by the cell, including: The piston is reset to its initial position between multiple formation processes or between a formation process and a subsequent aging process.
18. A single battery cell, characterized in that, It is prepared by the method for preparing a battery cell according to any one of claims 9-17.