Battery cell formation control method, controller and storage medium

Abstract

The application discloses a kind of battery cell formation control method and controller, storage medium, applied to battery cell field, the method can obtain the first difference of actual stress value and reference stress value of each battery cell at current time, and in the case where the first difference is outside first numerical range, determine the stress abnormality of battery cell, so compensate the stress value of battery cell.Thereby the stress value of each battery cell after compensation is close to the stress statistical value of multiple battery cells, improve the consistency of the stress of multiple battery cells, and then reduce the final form and performance difference between battery cells caused by reaction rate difference from the root, and then improve the performance consistency of multiple battery cells.And in the process of battery cell formation, in the case where the stress abnormality of battery cell is determined, the stress value of battery cell is compensated in time, can avoid the internal structure damage of battery cell caused by local pressure abnormality, improves the yield and safety performance of battery cell.

Description

Technical Field

[0001] This application relates to the field of batteries, specifically to a cell formation control method, controller, and storage medium. Background Technology

[0002] In the manufacturing process of secondary batteries such as lithium-ion batteries, the formation process is one of the key steps that determines the electrochemical performance, cycle life, and safety performance of the battery cell. The formation process requires applying a certain amount of mechanical pressure to the battery cell to ensure the tight adhesion between the internal electrodes and the separator, thereby reducing the interfacial resistance between the internal electrodes and the separator and promoting the uniform insertion, extraction, and transport of lithium ions.

[0003] However, in related technologies, after forming multiple cells from the same batch, the performance consistency of these multiple cells is poor. Summary of the Invention

[0004] In view of the above problems, this application provides a cell formation control method, controller, and storage medium, the technical solution including:

[0005] On the one hand, a cell formation control method is provided, the method including:

[0006] During the formation of multiple battery cells, the actual stress value of each battery cell at the current moment is obtained;

[0007] For each cell, the first difference between the actual force value and the reference force value is obtained. The reference force value can reflect the force statistics of multiple cells at the current moment.

[0008] When the first difference is outside the first numerical range, the force value of the compensated cell is adjusted.

[0009] Optional, the stress value of the compensated battery cell includes:

[0010] If the first difference is within the range of the second value, then increase the pressure on the cell for evacuation.

[0011] If the first difference is within the range of the third value, then increase the formation pressure applied to the cell;

[0012] The second numerical range is greater than the first numerical range, and the third numerical range is less than the first numerical range.

[0013] When the battery cell is under significant stress, the controller can determine that the cell is producing a large amount of gas. By compensating for the stress on the cell, a large amount of gas inside the cell can be expelled, thereby reducing the stress on the cell. When the battery cell is under relatively low stress, the controller compensates for the stress on the cell to increase the stress on the cell, thereby expelling a small amount of gas inside the cell.

[0014] Optionally, if the pressure applied to the battery cell during evacuation is increased, the method may also include:

[0015] Reduce the formation pressure applied to the battery cell.

[0016] Optionally, after compensating for the stress on the battery cell, the method further includes:

[0017] Reduce the pressure on the battery cells to remove air.

[0018] Optionally, the method also includes:

[0019] If the first difference is greater than the second value range, or the first difference is less than the third value range, the formation pressure applied to the cell will be reduced to a preset pressure, and a first alarm message will be issued.

[0020] Optionally, the first difference between the actual force value and the reference force value is obtained, including:

[0021] Based on the actual force value of the battery cell at the current moment, obtain the actual force change rate of the battery cell at the current moment;

[0022] Obtain the second difference between the actual rate of change of force and the reference rate of change of force. The reference rate of change of force contains statistical values ​​that reflect the rate of change of force of multiple cells at the current moment.

[0023] If the second difference is within the range of the fourth value, then the first difference between the actual force value and the reference force value is obtained.

[0024] Optionally, the method also includes:

[0025] If the second difference is outside the fourth value range, the formation pressure applied to the cell will be reduced to a preset pressure, and a second alarm message will be issued. If the second difference is outside the fourth value range, the controller can determine that the rate of change of force on the cell is abnormal. This situation may be caused by the cell rapidly generating gas or by failure to remove water, and therefore a second alarm message can be issued.

[0026] Optionally, if the first difference is within a first numerical range, the method further includes:

[0027] Obtain the actual temperature of each battery cell at the current moment;

[0028] If the third difference between the actual temperature and the reference temperature is outside the fifth value range, the formation pressure applied to the cell will be reduced to the preset pressure, and a third alarm message will be issued.

[0029] The reference temperature is used to reflect the temperature statistics of multiple cells at the current moment.

[0030] On the other hand, a computer-readable storage medium is provided that stores a computer program thereon, which, when executed by a processor, implements the cell formation control method described above.

[0031] In another aspect, a controller is provided, comprising: a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein when the processor executes the computer program, it implements the cell formation control method described above.

[0032] In summary, this invention provides a cell formation control method, controller, and storage medium. In this method, the controller can obtain a first difference between the actual force value of each cell at the current moment and a reference force value. If the first difference is outside a first numerical range, it determines that the cell is experiencing an abnormal force and therefore compensates for the cell's force value. This ensures that the compensated force value of each cell is close to the statistical force value of multiple cells, improving the consistency of force across multiple cells. This fundamentally reduces the differences in final form and performance between cells caused by differences in reaction rates, thereby improving the performance consistency of multiple cells.

[0033] Furthermore, during the cell formation process, timely compensation of the cell's stress when abnormal stress is detected can prevent damage to the cell's internal structure caused by localized pressure abnormalities, thereby improving the cell's yield and safety performance. Attached Figure Description

[0034] Figure 1 This is a schematic diagram of the structure of a cell formation control system provided in an embodiment of this application;

[0035] Figure 2 This is a partial structural schematic diagram of a cell formation control system provided in an embodiment of this application;

[0036] Figure 3 This is a partial structural schematic diagram of another cell formation control system provided in an embodiment of this application;

[0037] Figure 4 This is a flowchart of a cell formation control method provided in an embodiment of this application;

[0038] Figure 5 This is a flowchart of another cell formation control method provided in the embodiments of this application;

[0039] Figure 6 This is a schematic diagram of the structure of a controller provided in an embodiment of this application. Detailed Implementation

[0040] The embodiments of the technical solution of this application will now be described in detail with reference to the accompanying drawings. These embodiments are only used to more clearly illustrate the technical solution of this application and are therefore merely examples, and should not be used to limit the scope of protection of this application.

[0041] 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 pertains; the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the application; the terms “comprising” and “having”, and any variations thereof, in the specification, claims, and foregoing description of the drawings are intended to cover non-exclusive inclusion.

[0042] In the description of the embodiments of this application, technical terms such as "first" and "second" are used only to distinguish different objects and should not be construed as indicating or implying relative importance or implicitly specifying the number, specific order, or primary and secondary relationship of the indicated technical features. In the description of the embodiments of this application, "multiple" means two or more, unless otherwise explicitly defined.

[0043] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0044] In the description of the embodiments in this application, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, and B existing alone. Additionally, the character " / " in this document generally indicates that the preceding and following related objects have an "or" relationship.

[0045] In the description of the embodiments of this application, the term "multiple" refers to two or more (including two), similarly, "multiple sets" refers to two or more (including two sets), and "multiple pieces" refers to two or more (including two pieces).

[0046] In the description of the embodiments of this application, the technical terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the embodiments of this application and simplifying the description, and are not intended to 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 embodiments of this application.

[0047] In the description of the embodiments of this application, unless otherwise expressly specified and limited, technical terms such as "installation," "connection," "joining," and "fixing" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; 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; they can refer to the internal communication of two components or the interaction between two components. For those skilled in the art, the specific meaning of the above terms in the embodiments of this application can be understood according to the specific circumstances.

[0048] Figure 1 This is a schematic diagram of a cell formation control system provided in an embodiment of this application. Figure 2 and Figure 3 This is a partial structural schematic diagram of a cell formation control system provided in an embodiment of this application, as shown below. Figures 1 to 3 As shown, the system may include: at least two hollow support plates 001, a thin-film pressure sensor 002, at least two battery cells 003, at least two airbags 004, and a controller ( Figure 1 (Not shown).

[0049] Each hollow support plate 001 has at least one surface covered with an airbag 004, and each airbag 004 and its corresponding hollow support plate 001 can be referred to as an airbag clamp. At least two hollow support plates 001 are arranged side by side on the substrate, and a battery cell 003 can be placed between two adjacent airbags 004. The airbag 004 is inflatable and deflated.

[0050] During the formation of at least two cells 003, gas is injected into the airbag 004, which causes the airbag 004 to expand and come into contact with the cell 003, thereby squeezing the cell 003 disposed between adjacent airbags 004, thereby applying formation pressure to the cell 003.

[0051] Formation refers to the initial charge-discharge process of a newly prepared battery cell. Its purpose is to form a stable solid electrolyte interface film inside the cell, activate its electrochemical activity, and stabilize its internal structure. The formation process can include at least one of a pre-charge stage, a constant current stage, and a constant voltage stage. Formation pressure can refer to the controllable mechanical pressure applied to the cell casing by external equipment during the 003 formation process.

[0052] At the location where each hollow support plate 001 is covered by the airbag 004, there is at least one first air injection nozzle 005 and a second air injection nozzle 006 that communicate with the interior of the hollow support plate 001.

[0053] The interiors of each hollow support plate 001 are interconnected. Each first air injection nozzle 005 includes an electronic switch (e.g., a solenoid valve) located on the gas path connecting the cavity of the hollow support plate 001 to the external environment. When air injection is needed, simply turn on the electronic switch and connect it to an external air source, which will then inflate the air bladder 004 containing the first air injection nozzle 005. When deflation is needed, simply turn on the electronic switch to release the gas.

[0054] Multiple second air inlet nozzles 006 are interconnected and used to connect with an external air source, which is used to simultaneously inflate multiple air bags 004 through the multiple second air inlet nozzles 006.

[0055] Each airbag 004 has a thin-film pressure sensor 002 installed on the side closest to the battery cell 003. The thin-film pressure sensor 002 is used to detect the pressure on the battery cell 003 during the process of the airbag 004 clamping the battery cell 003. The thin-film pressure sensor 002 is in close contact with the surface of the airbag 004 to ensure that the pressure on the battery cell 003 during the formation process can be collected in real time.

[0056] Figure 4 This is a flowchart of a cell formation control method provided in an embodiment of this application, applied to a controller, such as... Figure 4 As shown, the method includes:

[0057] Step 401: During the formation of multiple battery cells, obtain the actual force value of each battery cell at the current moment.

[0058] These multiple battery cells can be from the same batch. During the cell formation process, gas is generated inside the cell, causing its volume to expand and push against the air bladder. This air bladder then exerts a reaction force on the cell. Therefore, the actual force detected on the cell is the sum of the formation pressure applied to the cell and the reaction force from the gas expansion. Thus, the actual force on the cell is not the same as the formation pressure applied to it. The controller uses this actual force value to determine the gas generation status of the cell. Since the gas generation may vary between different cells, the actual force values ​​will also differ between different cells.

[0059] Step 402: For each cell, obtain the first difference between the actual force value and the reference force value.

[0060] After obtaining the actual force value of each cell at the current moment, the controller can obtain the first difference between the actual force value and the reference force value.

[0061] The reference force value reflects the statistical values ​​of the forces exerted on multiple battery cells at the current moment. This reference force value can be the average, median, or mode of the actual force values ​​exerted on multiple battery cells at the current moment.

[0062] Step 403: If the first difference is outside the first numerical range, compensate the force value of the battery cell.

[0063] If the controller determines that the battery cell is under abnormal stress when the first difference is outside the first numerical range, it can compensate for the stress on the battery cell. If the first difference is within the first numerical range, the controller can determine that the battery cell is under normal stress, and therefore no compensation for the stress on the battery cell is needed.

[0064] Abnormal stress on a battery cell can include excessive or insufficient stress. When the stress is excessive, the controller can determine that the cell is generating too much gas. By compensating for the stress level, the controller can expel the gas inside the cell, thereby reducing the stress. When the stress is insufficient, the controller increases the stress level by compensating for the stress level, which can then expel a small amount of gas from inside the cell.

[0065] In summary, this application provides a cell formation control method. In this method, the controller can obtain a first difference between the actual force value of each cell at the current moment and a reference force value. If the first difference is outside a first numerical range, the controller determines that the cell is experiencing an abnormal force and compensates for the force value of the cell. This ensures that the compensated force value of each cell is close to the statistical force value of multiple cells, improving the consistency of force on multiple cells. This fundamentally reduces the differences in final form and performance between cells caused by differences in reaction rates, thereby improving the performance consistency of multiple cells.

[0066] Furthermore, during the cell formation process, timely compensation of the cell's stress when abnormal stress is detected can prevent damage to the cell's internal structure caused by localized pressure abnormalities, thereby improving the cell's yield and safety performance.

[0067] Figure 5 This is a flowchart of another cell formation control method provided in this application embodiment, applied to a controller, such as... Figure 5 As shown, the method may include:

[0068] Step 501: During the formation of multiple battery cells, obtain the actual force value of each battery cell at the current moment.

[0069] At the initial moment of multiple cell formation, the controller can control multiple airbags to apply initialization pressure to the multiple cells. Afterwards, the controller can execute steps 501 to 508.

[0070] These multiple battery cells can be from the same batch. During the cell formation process, gas is generated inside the cell, causing its volume to expand and push against the air bladder. This air bladder then exerts a reaction force on the cell. Therefore, the actual force detected on the cell is the sum of the formation pressure applied to the cell and the reaction force from the gas expansion. Thus, the actual force on the cell is not the same as the formation pressure applied to it. The controller uses this actual force value to determine the gas generation status of the cell. Since the gas generation may vary between different cells, the actual force values ​​will also differ between different cells.

[0071] refer to Figure 2 For each battery cell 003, the airbags 004 located on both sides of the battery cell 003 are each equipped with a thin-film pressure sensor 002 on the side closest to the battery cell 003. Both thin-film pressure sensors 002 are used to detect the pressure exerted on the battery cell 003. Therefore, the controller can use the average pressure detected by the two thin-film pressure sensors 002 at the current moment as the actual force value of the battery cell 003 at the current moment, or it can use the pressure detected by either thin-film pressure sensor 002 at the current moment as the actual force value of the battery cell 003 at the current moment.

[0072] Multiple thin-film pressure sensors can establish communication connections with the controller. For example, this communication connection can be a controller area network (CAN) bus, Ethernet, or other communication methods.

[0073] After acquiring the actual force value, the controller can filter it. For example, if the actual force value is greater than the first pressure or less than the second pressure, it can be discarded, and subsequent steps will not be executed. This removes noise data caused by equipment vibration, electromagnetic interference, etc., ensuring data accuracy.

[0074] Step 502: Based on the actual force value of the battery cell at the current moment, obtain the actual force change rate of the battery cell at the current moment.

[0075] The controller can obtain the time interval between the current moment and the previous moment, and obtain the force difference between the actual force value at the current moment and the actual force value at the previous moment. The ratio of the force difference to the time interval can then be used as the actual force change rate of the battery cell at the current moment. The previous moment is preceding the current moment and adjacent to the current moment.

[0076] If the current time is the initial time of cell formation, the controller can directly execute step 506 after executing step 501. If the current time is later than the initial time of cell formation, the controller can execute step 502 after executing step 501.

[0077] Step 503: Obtain the second difference between the actual rate of change of force and the benchmark rate of change of force.

[0078] After obtaining the actual rate of change of force on the battery cell at the current moment, the controller can obtain a second difference between the actual rate of change of force and the reference rate of change of force.

[0079] The reference force change rate can reflect the statistical value of the force change rate of multiple cells at the current moment. Optionally, the reference force change rate can be the mean, median, or mode of the actual force change rate of multiple cells at the current moment.

[0080] In this embodiment, the controller can pre-store the standard force change rate of different types of battery cells at various moments during the formation process. The standard force change rate at each moment is used to characterize the statistical value of the force change rate of multiple battery cells of that type when the force change rate is normal at that moment.

[0081] The controller can acquire the standard rate of change of force for cells of the same model at the current moment. If the difference between the reference rate of change of force and the standard rate of change of force is within a first range, the accuracy of the reference rate of change of force is considered high, and a second difference between the actual rate of change of force and the reference rate of change of force can be acquired. If the difference between the reference rate of change of force and the standard rate of change of force is outside the second range, the accuracy of the reference rate of change of force is considered low, and a second difference between the actual rate of change of force and the standard rate of change of force can be acquired, thus continuing with the following steps.

[0082] Step 504: Check whether the second difference is within the range of the fourth value.

[0083] After acquiring the second difference value, the controller can detect whether the second difference value is within the fourth value range. If the second difference value is within the fourth value range, the controller can determine that the rate of change of force on the battery cell is normal, and therefore can execute step 505. If the second difference value is outside the fourth value range, the controller can determine that the rate of change of force on the battery cell is abnormal. This situation may be caused by the battery cell rapidly generating gas or failing to remove water, and therefore can execute step 508.

[0084] In some embodiments of this application, the controller can obtain the mean rate of change and the standard deviation of the rate of change, and then obtain a fourth numerical range based on the mean rate of change and the standard deviation of the rate of change.

[0085] The lower limit of the fourth numerical range can be the difference between the mean rate of change and the standard deviation of the rate of change of a preset multiple, and the upper limit can be the sum of the mean rate of change and the standard deviation of the rate of change of a preset multiple. For example, the preset multiple can be 2.

[0086] Optionally, the mean rate of change can be the average of the actual force change rates of multiple cells at the current moment, and the standard deviation of the rate of change can be the standard deviation of the actual force change rates of multiple cells at the current moment. Alternatively, the mean rate of change can be the average of the actual force change rates of multiple cells at each moment from the start of formation to the current moment, and the standard deviation of the rate of change can be the standard deviation of the actual force change rates of multiple cells at each moment from the start of formation to the current moment.

[0087] Step 505: Obtain the first difference between the actual force value and the reference force value.

[0088] If the second difference is within the range of the fourth value, the controller can determine that the rate of change of force on the cell is normal, and thus can obtain the first difference between the actual force value of the cell and the reference force value.

[0089] The reference force value reflects the statistical values ​​of the forces exerted on multiple battery cells at the current moment. This reference force value can be the average, median, or mode of the actual force values ​​exerted on multiple battery cells at the current moment.

[0090] In this embodiment, the controller can pre-store the standard stress values ​​of different types of battery cells at various moments during the formation process. These standard stress values ​​at each moment are used to characterize the statistical values ​​of the stress values ​​of multiple battery cells of that type under normal stress conditions at that moment.

[0091] The controller can acquire the standard force value at the current moment for cells of the same model. If the difference between the reference force value and the standard force value is within a second range, the accuracy of the reference force value is considered high, and therefore a first difference between the actual force value and the reference force value can be acquired. If the difference between the reference force value and the standard force value is outside the second range, the accuracy of the reference force value is considered low, and therefore a first difference between the actual force value and the standard force value can be acquired, thus continuing with the following steps.

[0092] Step 506: Detect whether the first difference is within the range of the first value.

[0093] After acquiring the first difference, the controller can detect whether the first difference is within a first numerical range. If the first difference is outside the first numerical range, the controller can determine that the cell is under abnormal stress, and therefore can execute step 507. If the first difference is within the first numerical range, the controller can determine that the cell is under normal stress and no compensation is needed, and therefore can execute step 501 again after a preset time.

[0094] It should be noted that abnormal stress on the battery cell can include either excessive or insufficient stress. When the cell experiences excessive stress, the controller can determine that the cell is generating more gas. Conversely, when the cell experiences insufficient stress, the controller can determine that the cell is generating less gas.

[0095] Step 507: Compensate for the stress on the battery cell.

[0096] When the battery cell is under significant stress, the controller can determine that the cell is producing a large amount of gas. By compensating for the stress on the cell, a large amount of gas inside the cell can be expelled, thereby reducing the stress on the cell. When the battery cell is under relatively low stress, the controller compensates for the stress on the cell to increase the stress on the cell, thereby expelling a small amount of gas inside the cell.

[0097] In this embodiment, if the first difference is within the second numerical range, the controller can increase the pressure applied to the battery cell for evacuation. If the first difference is within the third numerical range, the formation pressure applied to the battery cell can be increased. The second numerical range is greater than the first numerical range, and the third numerical range is less than the first numerical range.

[0098] The first to fourth numerical ranges can all be determined using the mean force and the standard deviation of the force. The mean force can be the average of the actual force values ​​of multiple cells at the current moment, and the standard deviation of the force can be the standard deviation of the actual force values ​​of multiple cells at the current moment. Alternatively, the mean force can be the average of the actual force values ​​of multiple cells from the start of formation to the current moment, and the standard deviation of the force can be the standard deviation of the actual force values ​​of multiple cells from the start of formation to the current moment.

[0099] The lower limit of the first numerical range can be the difference between the mean force and the standard deviation of the force at the first multiple, and the upper limit can be the sum of the mean force and the standard deviation of the force at the first multiple. For example, the first multiple can be 2.

[0100] The lower limit of the second numerical range is greater than the sum of the mean force and the standard deviation of the force multiplied by the first factor, while the upper limit can be the sum of the mean force and the standard deviation of the force multiplied by the second factor. The second factor is greater than the first factor; for example, the second factor could be 3.

[0101] The lower limit of the third numerical range is greater than the difference between the mean force and the standard deviation of the force at the second multiple, while the upper limit can be the difference between the mean force and the standard deviation of the force at the first multiple.

[0102] For example, the first numerical range can be [me-2σ, me+2σ], the second numerical range can be (me+2σ, me+3σ], and the third numerical range can satisfy (me-3σ, me-2σ). me is the mean force, and σ is the standard deviation of the force.

[0103] Understandably, the battery cell has a vent, and the negative pressure device is connected to this vent. The controller can control the negative pressure device to increase the negative pressure, thereby increasing the pressure on the battery cell to expel air and accelerating the venting process. For example, the controller can control the negative pressure device to increase the negative pressure from -10 kPa to -30 kPa.

[0104] Because the battery cell is subjected to significant stress, the controller can reduce the formation pressure applied to the cell while increasing the pressure applied to the cell during evacuation. Optionally, the controller can control the formation pressure applied to the cell by the corresponding airbag.

[0105] In this embodiment, the controller can reduce the formation pressure applied to the battery cell at a first preset rate. This first preset rate is less than a preset value, thereby gradually reducing the formation pressure applied to the battery cell and avoiding sudden pressure changes.

[0106] After compensating for the stress on the battery cell, the controller can also reduce the pressure applied to the battery cell during evacuation. For example, the controller can control the negative pressure device to restore the negative pressure to -10 kPa.

[0107] For cells experiencing abnormal stress, the controller gradually reduces the formation pressure applied to the cell while simultaneously increasing the pressure applied to the cell for venting. This accelerates the venting process, causing the compensated stress value of the cell to converge with the statistical stress values ​​of multiple cells, thereby preventing sudden pressure changes. This continues until, at a target time, the first difference corresponding to the cell falls within a first numerical range. This target time is after the current time.

[0108] If the first difference is within the range of the third value, the controller can increase the formation pressure applied to the cell at a second preset rate. The second preset rate is less than a preset value, thereby gradually increasing the formation pressure applied to the cell and avoiding sudden pressure changes.

[0109] Step 508: Reduce the formation pressure applied to the cell to a preset pressure.

[0110] If the second difference is outside the range of the fourth value, the controller can determine that the rate of change of force on the cell is abnormal. Therefore, it can reduce the formation pressure applied to the cell to the preset pressure and issue a second alarm message.

[0111] The preset pressure is a safe pressure that ensures the battery cell can be safely removed from between two adjacent airbags. This second alarm message indicates abnormal gas production in the battery cell, thus reminding staff to perform a manual re-inspection.

[0112] By reducing the formation pressure applied to the battery cell to a preset pressure, the operator can remove the battery cell from between the airbags and then re-inspect the battery cell.

[0113] If the first difference is greater than the second value range, or the first difference is less than the third value range, the controller can determine that the cell is a severely abnormal cell. Therefore, the formation pressure applied to the cell can be reduced to a preset pressure, and a first alarm message can be issued.

[0114] In some embodiments of this application, if the first difference is within a first numerical range, the controller can obtain the actual temperature of each cell at the current moment and obtain a third difference between the actual temperature and the reference temperature. If the third difference is within a fifth numerical range, the controller can execute step 501 again after a preset time. If the third difference is outside the fifth numerical range, the controller can reduce the formation pressure applied to the cell to a preset pressure and issue a third alarm message. The reference temperature reflects the statistical temperature values ​​of multiple cells at the current moment.

[0115] The lower limit of the fifth numerical range can be the difference between the temperature mean and the temperature standard deviation of the reference multiple, and the upper limit can be the sum of the temperature mean and the temperature standard deviation of the reference multiple. For example, the reference multiple can be 2.

[0116] Optionally, the temperature mean can be the average of the actual temperatures of multiple cells at the current moment, and the temperature standard deviation can be the standard deviation of the actual temperatures of multiple cells at the current moment. Alternatively, the temperature mean can be the average of the actual temperatures of multiple cells at all moments from the start of formation to the current moment, and the temperature standard deviation can be the standard deviation of the actual temperatures of multiple cells at all moments from the start of formation to the current moment.

[0117] In this embodiment, the controller can pre-store the standard temperatures of different cell models at various moments during the formation process. These standard temperatures at each moment are used to characterize the statistical values ​​of the temperatures of multiple cells of that model under normal temperature conditions at that moment.

[0118] The controller can obtain the standard temperature of the same model as the multiple battery cells at the current moment. If the difference between the reference temperature and the standard temperature is within a third range, the accuracy of the reference temperature is considered high, and thus the third difference between the actual temperature and the reference temperature can be obtained. If the difference between the reference temperature and the standard temperature is outside the third range, the accuracy of the reference temperature is considered low, and thus the third difference between the actual temperature and the standard temperature can be obtained.

[0119] By detecting the actual temperature of each battery cell and combining the temperature rise changes of multiple battery cells, cells with abnormal temperatures can be identified in a timely manner, and defective products can be removed in advance.

[0120] During the formation of each battery cell, the controller can periodically execute the method provided in the embodiments of this application, thereby timely removing the generated gas from the battery cell until the formation process is completed.

[0121] By calculating the reference stress values ​​of multiple cells at multiple times, a reference curve characterizing the normal expansion law of the entire batch of cells can be obtained, and the reference curve can be dynamically updated as the formation stage progresses.

[0122] The method provided in this application treats all cells in the same batch (e.g., located in the same substrate) as a dynamic and collaborative intelligent group. By sharing the stress values ​​of all individuals in real time, and calculating the benchmark stress value of the group based on the stress values ​​of multiple cells, the method uses the benchmark stress value as a reference to detect and adjust abnormal cells.

[0123] Due to inherent differences in electrode coating thickness, active material distribution, and separator porosity during battery cell production, using a fixed pressure threshold to determine the normality of the actual stress value of a battery cell can lead to several issues. Some cells may experience separator damage due to excessive pressure, while others may suffer electrode delamination due to insufficient pressure. This results in high dispersion in performance parameters such as capacity, internal resistance, and cycle life across the entire batch of cells. Adopting this benchmark stress value allows for adaptation to the individual expansion needs of the entire batch of cells, establishing a correlation between the actual stress values ​​of the entire batch. This enables a closed-loop upgrade of pressure regulation from "individual optimization of a single cell" to "group collaborative optimization," fundamentally reducing the differences in final form and performance between cells caused by variations in reaction rates. This effectively reduces the dispersion of key performance parameters such as capacity, internal resistance, and cycle life within the same batch of cells, significantly improving the performance consistency of the entire batch and meeting the stringent requirements for cell consistency in power batteries. This solution addresses the issue of fixed pressure thresholds failing to accommodate the individual differences among battery cells. The benchmark stress value is generated based on the actual stress values ​​of multiple battery cells, better reflecting the true expansion characteristics of the entire batch of cells and providing a precise reference for pressure regulation. By periodically detecting the actual stress values ​​of the battery cells and dynamically compensating for the stress on the cells, the real-time performance and accuracy of the regulation are improved.

[0124] Furthermore, during the formation process, abnormal cells can be identified and proactively intervened in advance. By comparing the deviation between the actual stress value of a single cell and the baseline stress value of the group, for example, if the stress change rate of a certain cell is large, it can be determined that it may have an internal short circuit risk. Thus, the problematic cell can be accurately located in the early stage of abnormal gas generation and expansion (rather than after the failure occurs), avoiding damage to the internal structure of the cell caused by local pressure anomalies. Early identification and intervention of abnormal cells reduces the scrap rate of cells due to improper pressure, improves overall production efficiency, and enhances the yield and safety performance of cells. At the same time, it avoids the failure to capture the relative abnormal signal in time, resulting in passive handling only after the failure occurs. In the case of cell abnormality, the stress of the cell is compensated in time, avoiding secondary damage caused by extreme voltage regulation of the abnormal cell, making the pressure distribution of the entire batch of cells more uniform, and further reducing the performance difference of the group.

[0125] The controller can also store the actual stress value, reference stress value, actual stress change rate, reference stress change rate, actual temperature, and reference temperature of each cell at various times. When producing cells of the same model later, the data in the database can be called to optimize the reference values ​​and thresholds used in the embodiments of this application, so as to achieve continuous iterative upgrades of the process. This data can serve as the core data source for battery manufacturing process quality control, process optimization decision support system, and product performance prediction model. Before formation, historical data of the same type of cells can be called to compare batch differences, and anomalies can be avoided in batches.

[0126] In summary, this application provides a cell formation control method. In this method, the controller can obtain a first difference between the actual force value of each cell at the current moment and a reference force value. If the first difference is outside a first numerical range, the controller determines that the cell is experiencing an abnormal force and compensates for the force value of the cell. This ensures that the compensated force value of each cell is close to the statistical force value of multiple cells, improving the consistency of force on multiple cells. This fundamentally reduces the differences in final form and performance between cells caused by differences in reaction rates, thereby improving the performance consistency of multiple cells.

[0127] Furthermore, during the cell formation process, timely compensation of the cell's stress when abnormal stress is detected can prevent damage to the cell's internal structure caused by localized pressure abnormalities, thereby improving the cell's yield and safety performance.

[0128] This application provides a computer-readable storage medium storing a computer program thereon, which, when executed by a processor, implements the cell formation control method described in the above embodiments.

[0129] Figure 6 This is a schematic diagram of the structure of a controller provided in an embodiment of this application, such as... Figure 6 As shown, the controller 60 may include: a memory 601, a processor 602, and a computer program stored in the memory 601 and executable on the processor 602. When the processor 602 executes the computer program, it implements the cell formation control method described in the above embodiments.

[0130] This application also provides a computer program product, including a computer program that, when executed by a processor, implements the cell formation control method described in the above embodiments.

[0131] This application provides a cell formation control device, the device comprising:

[0132] The first acquisition module is used to acquire the actual force value of each cell at the current moment during the formation of multiple cells.

[0133] The second acquisition module is used to acquire, for each cell, the first difference between the actual force value and the reference force value, where the reference force value can reflect the force statistics of multiple cells at the current moment;

[0134] The compensation module is used to compensate for the stress value of the battery cell when the first difference is outside a first numerical range.

[0135] Optional, a compensation module is used for:

[0136] If the first difference is within the range of the second value, then increase the pressure on the cell for evacuation.

[0137] If the first difference is within the range of the third value, then increase the formation pressure applied to the cell;

[0138] The second numerical range is greater than the first numerical range, and the third numerical range is less than the first numerical range.

[0139] Optional, a compensation module is used for:

[0140] While increasing the pressure of evacuating the battery cell, the formation pressure applied to the battery cell is reduced.

[0141] Optionally, the device may also include:

[0142] The pressure adjustment module is used to reduce the pressure applied to the battery cell after compensating for the stress value of the battery cell.

[0143] Optionally, the pressure adjustment module is also used for:

[0144] If the first difference is greater than the second value range, or the first difference is less than the third value range, the formation pressure applied to the cell will be reduced to a preset pressure, and a first alarm message will be issued.

[0145] Optionally, a second acquisition module is used for:

[0146] Based on the actual force value of the battery cell at the current moment, obtain the actual force change rate of the battery cell at the current moment;

[0147] Obtain the second difference between the actual rate of change of force and the reference rate of change of force. The reference rate of change of force contains statistical values ​​that reflect the rate of change of force of multiple cells at the current moment.

[0148] If the second difference is within the range of the fourth value, then the first difference between the actual force value and the reference force value is obtained.

[0149] Optionally, the pressure adjustment module is also used for:

[0150] If the second difference is outside the range of the fourth value, the formation pressure applied to the cell will be reduced to the preset pressure, and a second alarm message will be issued.

[0151] Optionally, the device may also include:

[0152] The third acquisition module is used to acquire the actual temperature of each cell at the current moment when the first difference is within the first numerical range.

[0153] The pressure adjustment module is also used to reduce the formation pressure applied to the cell to a preset pressure and issue a third alarm message if the third difference between the actual temperature and the reference temperature is outside the fifth numerical range.

[0154] The reference temperature is used to reflect the temperature statistics of multiple cells at the current moment.

[0155] In summary, this application provides a cell formation control device. This device can obtain a first difference between the actual force value of each cell at the current moment and a reference force value. If the first difference is outside a first numerical range, it determines that the cell is experiencing an abnormal force and therefore compensates for the cell's force value. This ensures that the compensated force values ​​of each cell are close to the statistical force values ​​of multiple cells, improving the consistency of force across multiple cells. This fundamentally reduces the differences in final shape and performance between cells caused by differences in reaction rates, thereby improving the performance consistency of multiple cells. Furthermore, during the cell formation process, timely compensation of the cell's force when an abnormal force is detected can prevent internal structural damage caused by localized pressure anomalies, improving cell yield and safety performance.

[0156] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and not to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. These modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application, and they should all be covered within the scope of the claims and specification of this application. In particular, as long as there is no structural conflict, the various technical features mentioned in the embodiments can be combined in any way. This application is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. A cell formation control method, characterized in that, The method includes: During the formation of multiple battery cells, the actual force value of each battery cell at the current moment is obtained; For each of the battery cells, a first difference between the actual force value and the reference force value is obtained, wherein the reference force value can reflect the force statistics of multiple battery cells at the current moment; If the first difference is outside the first numerical range, the stress value of the battery cell is compensated. The process of obtaining the first difference between the actual force value and the reference force value includes: Based on the actual force value of the battery cell at the current moment and the actual force value at the previous moment, the actual force change rate of the battery cell at the current moment is obtained; Obtain the second difference between the actual force change rate and the reference force change rate, wherein the reference force change rate contains statistical values ​​that reflect the force change rates of multiple cells at the current moment; If the second difference is within the fourth numerical range, then the first difference between the actual force value and the reference force value is obtained.

2. The method according to claim 1, characterized in that, Compensating for the stress on the battery cell includes: If the first difference is within the range of the second value, then increase the pressure of evacuating the battery cell. If the first difference is within the range of the third value, then the formation pressure applied to the cell is increased; Wherein, the second numerical range is greater than the first numerical range, and the third numerical range is less than the first numerical range.

3. The method according to claim 2, characterized in that, When increasing the pressure of evacuating the battery cell, the method further includes: Reduce the formation pressure applied to the battery cell.

4. The method according to claim 2, characterized in that, After compensating for the stress on the battery cell, the method further includes: Reduce the pressure applied to the battery cell during evacuation.

5. The method according to claim 2, characterized in that, The method further includes: If the first difference is greater than the second value range, or the first difference is less than the third value range, the formation pressure applied to the cell will be reduced to a preset pressure, and a first alarm message will be issued.

6. The method according to claim 1, characterized in that, The method further includes: If the second difference is outside the range of the fourth value, the formation pressure applied to the cell will be reduced to a preset pressure, and a second alarm message will be issued.

7. The method according to any one of claims 1 to 6, characterized in that, When the first difference is within the first numerical range, the method further includes: Obtain the actual temperature of each of the battery cells at the current moment; If the third difference between the actual temperature and the reference temperature is outside the fifth numerical range, the formation pressure applied to the cell will be reduced to a preset pressure, and a third alarm message will be issued. The reference temperature is used to reflect the temperature statistics of the multiple battery cells at the current moment.

8. A computer-readable storage medium, characterized in that, It stores a computer program, which, when executed by a processor, implements the cell formation control method according to any one of claims 1-7.

9. A controller, characterized in that, include: A memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor, when executing the computer program, implements the cell formation control method according to any one of claims 1-7.

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