Charging and discharging control method of battery cell, battery management system, battery pack and device

Abstract

The application discloses a battery management system, a battery pack, and an equipment. The method comprises the following steps: acquiring an electrochemical impedance of a battery cell in a battery pack, battery cell state data of the battery cell, and a first charge-discharge rate corresponding to a charge-discharge current of the battery cell; acquiring a second charge-discharge rate corresponding to the electrochemical impedance and the battery cell state data; and adjusting the charge-discharge current of the battery cell according to a relative rate between the first charge-discharge rate and the second charge-discharge rate, and controlling the charge-discharge of the battery cell. The method provided in the application can improve the charge-discharge control precision of the battery cell by controlling the charge-discharge of the battery cell according to the charge-discharge rate determined by the electrochemical impedance of the battery cell.

Description

Technical Field

[0001] This application relates to the field of electrochemical technology, and in particular to a method for controlling the charging and discharging of a battery cell, a battery management system, a battery pack, and related equipment. Background Technology

[0002] The charge / discharge rate of a battery cell has a significant impact on battery performance. If the charge / discharge rate of a battery cell is too high or too low, it will affect the cell's lifespan and safety.

[0003] In related technologies, a pre-set correlation is typically used to determine the charge / discharge rate of a battery cell. However, the charge / discharge rate determined by this method does not match the actual state of the battery cell. Therefore, improving the charge / discharge control accuracy of battery cells is a problem that urgently needs to be solved. Summary of the Invention

[0004] This application provides a charging and discharging control method for a battery cell, a battery management system, a battery pack, and a device. The method controls the charging and discharging of the battery cell based on the charging and discharging rate determined by the electrochemical impedance of the battery cell, thereby improving the charging and discharging control accuracy of the battery cell.

[0005] In a first aspect, this application provides a method for controlling the charging and discharging of a battery cell. The method includes: acquiring the electrochemical impedance of a battery cell in a battery pack, the cell state data of the battery cell, and a first charge / discharge rate corresponding to the charging and discharging current of the battery cell, wherein the cell state data includes the cell's usage status, cell temperature, and state of charge; acquiring a second charge / discharge rate corresponding to the electrochemical impedance and the cell state data; adjusting the charging and discharging current of the battery cell according to the relative ratio between the first charge / discharge rate and the second charge / discharge rate to obtain an adjusted charging and discharging current; and controlling the charging and discharging of the battery cell through the adjusted charging and discharging current.

[0006] As can be seen from the above, the first charge / discharge rate is determined based on the charge / discharge current and the cell capacity. It cannot reflect the internal state of the cell, and directly using the first charge / discharge rate to control the cell's charge / discharge results in low control accuracy. However, the cell's electrochemical impedance changes with its state of charge (SOC) and temperature, reflecting the internal electrochemical reactions. In this embodiment, the second charge / discharge rate is determined based on the relationship between the electrochemical impedance and the charge / discharge rate, rather than the overall internal resistance of the cell. The second charge / discharge rate aligns with the actual state of the cell. Therefore, controlling the cell's charge / discharge current using the relative ratio between the first and second charge / discharge rates allows for more precise cell control, thereby improving the charge / discharge control accuracy.

[0007] Therefore, the solution provided in this application embodiment controls the charging and discharging of the battery cell based on the charge and discharge rate determined by the electrochemical impedance of the battery cell, which can improve the charging and discharging control accuracy of the battery cell.

[0008] In some embodiments, obtaining a first charge / discharge rate of a battery cell includes: obtaining the electrochemical impedance of all cells in a battery pack; identifying outlier cells from all cells based on the electrochemical impedance of each cell in the battery pack, wherein an outlier cell is a cell whose impedance deviation from the electrochemical impedance of other cells in the battery pack is greater than a preset threshold; and obtaining a first charge / discharge rate of the outlier cell based on the charge / discharge current and the cell capacity of the outlier cell.

[0009] Identifying outlier cells in the battery pack and obtaining their first charge / discharge rate for use in charge / discharge control can improve the efficiency of charge / discharge control for cells within the battery pack.

[0010] In some embodiments, identifying outlier cells from all cells based on the electrochemical impedance of each cell in the battery pack includes: determining an impedance threshold based on the electrochemical impedance of all cells; determining the impedance deviation of each cell based on the relative value between the electrochemical impedance of each cell in the battery pack and the impedance threshold; and identifying cells from all cells whose impedance deviation is greater than a preset threshold to obtain outlier cells.

[0011] The impedance threshold is determined by using the electrochemical impedance of all cells, so that the determination of the impedance threshold can be adapted to the working state of the cells in the battery pack. Based on this impedance threshold, outlier cells in the battery pack can be quickly and accurately located.

[0012] In some embodiments, adjusting the charging and discharging current of the battery cell according to the relative ratio between the first charging and discharging rate and the second charging and discharging rate to control the charging and discharging of the battery cell includes: adjusting the charging and discharging rate of the outlier battery cell when the relative ratio is greater than the first rate threshold to obtain the adjusted charging and discharging rate; determining the adjusted charging and discharging current according to the adjusted charging and discharging rate and the battery cell capacity of the outlier battery cell; and controlling the charging and discharging of the battery cell through the adjusted charging and discharging current.

[0013] When the difference between the first rate threshold and the second rate threshold is large, the charge and discharge rate of the battery cell is adjusted to reduce the difference between the adjusted charge and discharge rate and the second rate threshold, thereby improving the control accuracy of the battery cell's charge and discharge and optimizing the battery cell's charge and discharge performance.

[0014] In some embodiments, when the relative rate is greater than a first rate threshold, the charge and discharge rate of the outlier cell is adjusted to obtain an adjusted charge and discharge rate, including: when the relative rate is greater than the first rate threshold and less than a second rate threshold, adjusting the first charge and discharge rate of the outlier cell to a second charge and discharge rate, wherein the first rate threshold is less than the second rate threshold.

[0015] By adjusting the charge / discharge rate of the battery cell to a second charge / discharge rate, and then controlling the charge / discharge of the battery cell at the second charge / discharge rate, the control accuracy of the charge / discharge of the battery cell can be improved.

[0016] In some embodiments, the charge and discharge control method for the battery cell further includes: when the relative rate is greater than a second rate threshold, obtaining an adjustment coefficient corresponding to the relative rate, wherein the adjustment coefficient is positively correlated with the relative rate; determining an adjustment range based on the product between the adjustment coefficient and the relative rate; adjusting the first charge and discharge rate according to the adjustment range to obtain a third charge and discharge rate, wherein the relative value between the third charge and discharge rate and the second charge and discharge rate is less than the first rate threshold.

[0017] The adjustment range is determined by an adjustment coefficient corresponding to the relative rate, and then the charge and discharge rate of the outlier cell is adjusted based on this adjustment range. This ensures that the charge and discharge current of the cell does not change abruptly during the adjustment process, thus improving the cell's performance. At the same time, the adjustment time is not too long, which can effectively adjust the charge and discharge current.

[0018] In some embodiments, adjusting the first charge / discharge rate by an adjustment range to obtain a third charge / discharge rate includes: increasing the first charge / discharge rate by an adjustment range when the first charge / discharge rate is greater than the second charge / discharge rate to obtain a third charge / discharge rate; and / or decreasing the first charge / discharge rate by an adjustment range when the first charge / discharge rate is less than the second charge / discharge rate to obtain a third charge / discharge rate.

[0019] The first charge / discharge rate is adjusted in a manner that tends towards the second charge / discharge rate in order to improve the control accuracy of the cell's charge / discharge and optimize the cell's charge / discharge performance.

[0020] In some embodiments, obtaining the electrochemical impedance of cells in a battery pack includes: obtaining cell state data and impedance spectrum for each cell in the battery pack, wherein the impedance spectrum is used to characterize the correlation between cell state data constructed under the use state and electrochemical impedance, the use state including the resting state, charging state or discharging state; and obtaining the electrochemical impedance corresponding to the cell state data of all cells from the impedance spectrum.

[0021] Since the impedance spectrum in the embodiments of this application is constructed in the electrical equipment, the impedance spectrum can match the actual usage state of the electrical equipment. Therefore, in the charge and discharge control of the battery cell, the electrochemical impedance of the battery cell can be determined by using the impedance spectrum, thereby determining the charge and discharge rate and adjusting the charge and discharge current. Based on the adjusted charge and discharge current, the charge and discharge control of the battery cell can be performed, which can improve the control accuracy of the charge and discharge of the battery cell.

[0022] In some embodiments, obtaining a second charge / discharge rate corresponding to electrochemical impedance and cell state data includes: obtaining a preset correlation between cell impedance, cell state, and charge / discharge rate; and determining a second charge / discharge rate corresponding to electrochemical impedance and cell state data from the preset correlation.

[0023] Since the aforementioned preset correlation is determined by the cell impedance, cell state, and cell charge / discharge rate, the second charge / discharge rate obtained based on this preset correlation is more closely matched with the actual state of the cell, laying the foundation for precise control of subsequent cell charge / discharge.

[0024] In some embodiments, the battery cell charging and discharging control method further includes: acquiring the historical electrochemical impedance and historical charge / discharge rate of the battery cell under the historical operating conditions of the electrical equipment; and adjusting the preset correlation relationship based on the historical electrochemical impedance and historical charge / discharge rate to obtain the adjusted preset correlation relationship.

[0025] The historical operating data of the electrical equipment was also taken into account during the adjustment of the preset correlation, so that the adjusted preset correlation can be adapted to the electrical equipment. Then, the charging and discharging of the battery cell can be controlled based on the adjusted preset correlation, which can improve the control accuracy of the charging and discharging of the battery cell.

[0026] In some embodiments, the preset correlation is adjusted based on the historical electrochemical impedance and the historical charge-discharge rate to obtain the adjusted preset correlation, including: obtaining the fourth charge-discharge rate corresponding to the historical electrochemical impedance from the preset correlation; and adjusting the preset correlation based on the relative value between the historical charge-discharge rate and the fourth charge-discharge rate to obtain the adjusted preset correlation.

[0027] By adjusting the preset correlation relationship based on the relative value between the historical charge / discharge rate and the fourth charge / discharge rate, the adjusted preset correlation relationship can be made to match the actual state of the electrical equipment, laying the foundation for precise control of battery cell charge / discharge.

[0028] Secondly, this application also provides a battery management system, which includes: a data acquisition circuit for acquiring the electrochemical impedance of a cell in a battery pack, cell state data of the cell, a first charge-discharge rate corresponding to the charge-discharge current of the cell, and a second charge-discharge rate corresponding to the electrochemical impedance and cell state data, wherein the cell state data includes the cell's usage status, cell temperature, and state of charge; and a processor connected to the data acquisition circuit for adjusting the charge-discharge current of the cell according to the relative ratio between the first charge-discharge rate and the second charge-discharge rate to obtain the adjusted charge-discharge current, and controlling the charge-discharge of the cell through the adjusted charge-discharge current.

[0029] Thirdly, this application provides a battery pack including battery cells and a battery management system as described in the second aspect.

[0030] Fourthly, this application provides an electrical device that includes a battery pack as described in the third aspect.

[0031] The above description is only an overview of the technical solution of this application. In order to better understand the technical means of this application and to implement it in accordance with the contents of the specification, and to make the above and other objects, features and advantages of this application more obvious and understandable, the following are specific embodiments of this application. Attached Figure Description

[0032] The features, advantages, and technical effects of exemplary embodiments of this application will now be described with reference to the accompanying drawings.

[0033] Figure 1 This is a schematic diagram of the structure of a battery management system according to an embodiment of this application;

[0034] Figure 2 This is one of the flowcharts illustrating a charging and discharging control method for a battery cell according to an embodiment of this application;

[0035] Figure 3 This is a graph showing the relationship between charge transfer impedance and charge / discharge rate of the battery cell according to one embodiment of this application.

[0036] Figure 4 This is a schematic diagram of the structure of an electrical device according to an embodiment of this application;

[0037] Figure 5 This is a flowchart illustrating a method for determining the first charge / discharge rate according to an embodiment of this application.

[0038] Figure 6 This is a flowchart illustrating a method for determining outlier cells according to an embodiment of this application.

[0039] Figure 7This is a flowchart illustrating a method for determining the second charge / discharge rate according to an embodiment of this application.

[0040] Figure 8 This is a schematic flowchart illustrating a method for adjusting a preset association relationship according to an embodiment of this application;

[0041] Figure 9 This is a schematic flowchart illustrating a method for adjusting a preset association relationship according to an embodiment of this application;

[0042] Figure 10 This is a second schematic flowchart of a battery cell charging and discharging control method according to an embodiment of this application;

[0043] Figure 11 This is a schematic flowchart of a method for adjusting the charge / discharge rate according to one embodiment of this application;

[0044] Figure 12 This is a second schematic flowchart illustrating a method for adjusting the charge / discharge rate according to an embodiment of this application.

[0045] Figure 13 This is a schematic diagram of the structure of an electronic device according to another embodiment of this application.

[0046] The accompanying drawings are not necessarily drawn to scale. Detailed Implementation

[0047] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0048] 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.

[0049] 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.

[0050] In this application, the term "embodiment" is used to mean that a specific 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 in the specification does not necessarily refer to the same embodiment, nor is it a mutually exclusive, independent, or alternative embodiment. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described in this application can be combined with other embodiments.

[0051] 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.

[0052] 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).

[0053] 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.

[0054] 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.

[0055] The charge / discharge rate refers to the maximum charge / discharge rate of a battery cell per unit time, usually expressed as a multiple. The charge / discharge rate of a battery cell has a significant impact on its charge / discharge control. For example, at high rates, excessive heat is generated inside the cell, leading to an increase in internal temperature and changes in internal resistance. This not only affects the charge / discharge process but also the cell's lifespan and safety. Therefore, to improve the control accuracy of charge / discharge and extend the cell's lifespan, it is necessary to set an appropriate charge / discharge rate.

[0056] In related technologies, the charge / discharge rate of a battery cell is typically determined based on the user experience of the cell. For example, there is a certain correlation between the internal resistance of the cell and the charge / discharge rate. The internal resistance of the cell is related to its manufacturing process. By using the charge / discharge rates and internal resistances recorded in different battery cell specifications available on the market, a correlation coefficient is calculated to determine the current charge / discharge rate of the cell. However, in these technologies, the internal resistance of the cell is determined by the current and voltage flowing into the cell, without considering changes within the cell itself. In practical applications, electrochemical reactions occur within the cell, and the electrochemical impedance changes with the cell's temperature, SOC (State of Charge), and other factors. Therefore, determining the charge / discharge rate of a battery cell solely based on the internal resistance determined by the current and voltage flowing into the cell suffers from low accuracy.

[0057] Therefore, in the relevant technologies, the influence of the internal state of the battery cell on the charging and discharging process is not considered when determining the charging and discharging rate of the battery cell. This results in the determined charging and discharging rate not matching the actual state of the battery cell. Consequently, using this charging and discharging rate to control the charging and discharging of the battery cell will reduce the accuracy of the charging and discharging control.

[0058] To address the problems existing in the prior art, embodiments of this application provide a method for controlling the charging and discharging of a battery cell, a battery management system, a battery pack, and a device. In embodiments of this application, the battery management system can control the charging and discharging of the battery cell at regular intervals, or, when it detects that the electrochemical impedance of the battery cell does not meet preset conditions (e.g., the charge transfer impedance of the battery cell is greater than a set impedance threshold), adjust the charging and discharging rate of the battery cell to achieve charging and discharging control of the battery cell.

[0059] Specifically, in this embodiment, the battery management system calculates the first charge / discharge rate of the battery cell based on its charge / discharge current and capacity. Then, based on the cell's electrochemical impedance and state of matter data, it determines the second charge / discharge rate from the correlation between electrochemical impedance and charge / discharge rate. Furthermore, it determines whether to adjust the cell's charge / discharge current based on the relative ratio between the first and second charge / discharge rates. If adjustment is needed, the specific adjustment range is determined to ensure the cell can charge and discharge with a reasonable current, thereby improving the cell's charge / discharge control accuracy.

[0060] In one embodiment, Figure 1 This illustration shows a schematic diagram of the battery management system provided in an embodiment of this application. Figure 1 As can be seen, in the embodiments of this application, the battery management system includes at least a data acquisition circuit 10 and a processor 20.

[0061] In this embodiment of the application, the data acquisition circuit 10 may include an electrical signal acquisition device (e.g., a voltage acquisition device, a current acquisition device, a temperature sensor, etc.) for acquiring the electrochemical impedance of the cells in the battery pack, the cell state data of the cells, a first charge-discharge rate corresponding to the charge-discharge current of the cells, and a second charge-discharge rate corresponding to the electrochemical impedance and the cell state data.

[0062] In this embodiment, the electrochemical impedance of the battery cell is an alternating current impedance, which may include the ohmic impedance, charge transfer impedance, and film impedance of the battery cell. The charge transfer impedance reflects the resistance to charge transfer during charging and discharging, directly affecting energy conversion efficiency and output stability. Furthermore, a higher charge transfer impedance accelerates the aging of electrode materials in the battery cell and shortens its cycle life. Therefore, in this embodiment, the battery management system primarily uses the charge transfer impedance of the battery cell to control its charging and discharging; that is, in this embodiment, electrochemical impedance mainly refers to the charge transfer impedance of the battery cell.

[0063] In the above embodiments, the battery management system also deploys an EIS (Electrochemical Impedance Spectroscopy) detection circuit. The EIS detection circuit is connected to the battery cell and the data acquisition circuit. It can detect the electrochemical impedance of the battery cell in the electrical device and transmit the detected electrochemical impedance to the data acquisition circuit.

[0064] In this embodiment of the application, the cell status data may include the cell's usage status, the cell's SOC, the cell's temperature, and other data. The cell's usage status may include a resting state, a charging state, or a discharging state.

[0065] In this embodiment, the first charge / discharge rate of the battery cell is determined by the real-time charge / discharge current of the battery cell and the capacity of the battery cell, that is, the first charge / discharge rate is the actual charge / discharge rate of the battery cell; the second charge / discharge rate of the battery cell is the charge / discharge rate obtained by querying a pre-set correlation relationship based on the electrochemical impedance, which can be used as a charge / discharge rate benchmark to adjust the charge / discharge current of the battery cell. The aforementioned correlation relationship is a pre-built correlation relationship between the battery cell impedance and the charge / discharge rate.

[0066] In this embodiment of the application, the processor 20 is connected to the data acquisition circuit and is used to adjust the charging and discharging current of the battery cell according to the relative ratio between the first charging and discharging rate and the second charging and discharging rate, thereby controlling the charging and discharging of the battery cell.

[0067] It should be noted that, in this embodiment, the second charge / discharge rate is determined by the cell's electrochemical impedance and cell state data. Since electrochemical impedance reflects the cell's internal state, using the relative ratio between the first and second charge / discharge rates to control the cell's charge / discharge takes into account the cell's internal state. Controlling the cell's charge / discharge in this way can effectively improve its performance and extend its lifespan. Furthermore, compared to existing technologies, this method provides more precise charge / discharge control.

[0068] In addition, in this embodiment, the relative ratio between the first charge / discharge rate and the second charge / discharge rate is used to control the charge and discharge of the battery cell. A suitable adjustment strategy is selected according to the magnitude of the relative ratio to reduce the risk of battery cell abnormalities caused by drastic changes in the charge and discharge current, thereby improving the reliability and safety of battery cell control.

[0069] This concludes the introduction to the battery management system provided in the embodiments of this application.

[0070] The following describes the charging and discharging control method for the battery cell provided in the embodiments of this application, with the battery management system as the executing entity.

[0071] In one embodiment, Figure 2 A flowchart illustrating a method for controlling the charging and discharging of a battery cell is shown, which can be applied to a battery management system. For example... Figure 2 As shown, the method may include the following steps S201 to S203:

[0072] Step S201: Obtain the electrochemical impedance of the cells in the battery pack, the cell state data of the cells, and the first charge / discharge rate corresponding to the charge / discharge current of the cells.

[0073] In step S201, the battery pack can be deployed in electrical equipment, such as new energy vehicles or battery swapping stations. The battery pack may include multiple battery cells. In this embodiment, the electrical equipment is equipped with a battery management system connected to the battery pack, used for managing, analyzing performance, and detecting anomalies in the battery cells. The battery management system includes a data acquisition circuit that can acquire data such as the electrochemical impedance of the battery cells, cell state data, and the first charge / discharge rate of the cells.

[0074] It should be noted that electrochemical impedance can include the ohmic impedance of the battery cell, charge transfer impedance, membrane impedance, etc. In this embodiment, electrochemical impedance including charge transfer impedance is used as an example for explanation.

[0075] In step S201, the cell status data includes the cell's usage status (e.g., charging status, discharging status), cell temperature, SOC, etc.

[0076] In step S201, the first charge / discharge rate of the battery cell is the charge / discharge rate of the battery cell in its operating state, which can be determined by the charge / discharge current of the battery cell and the nominal capacity of the battery cell. For example, the first charge / discharge rate can be determined by formula (1):

[0077] (1)

[0078] In formula (1), C is the first charge / discharge rate of the battery cell, I is the charge / discharge current of the battery cell, and S is the nominal capacity of the battery cell.

[0079] For example, the battery management system is equipped with an EIS detection circuit, which can detect the electrochemical impedance of the battery cell in the device according to the detection requirements. The battery cell acquisition circuit in the battery management system can collect parameters such as current, voltage, and temperature of the battery cell. By analyzing these parameters, the battery cell state data can be determined and the first charge-discharge rate of the battery cell can be calculated. For example, the direction of the charge-discharge current of the battery cell can be used to determine whether the battery cell is in a charging state or a discharging state. For another example, the SOC of the battery cell can be estimated by detecting the open circuit voltage of the battery cell. For another example, the first charge-discharge rate of the battery cell can be calculated by combining the collected charge-discharge current of the battery cell with formula (1).

[0080] Step S202: Obtain the second charge / discharge rate corresponding to the electrochemical impedance and cell state data.

[0081] In step S202, the second charge / discharge rate can be determined by a pre-established correlation between cell impedance, cell state, and charge / discharge rate. For example, Figure 3This diagram shows the relationship between charge transfer impedance and charge / discharge rate of a battery cell under a certain cell condition. After obtaining the charge transfer impedance of the cell, through... Figure 3 The second charge / discharge rate can be obtained from the relationship curve shown.

[0082] It should be noted that the correlation between electrochemical impedance and charge / discharge rate of the cell varies under different cell states. Therefore, in order to improve the accuracy of cell control, in this embodiment, a preset correlation can be constructed under different cell state data. In practical applications, the correlation that matches the cell state data is selected from multiple preset correlations to determine the second charge / discharge rate of the cell.

[0083] Step S203: Adjust the charging and discharging current of the battery cell according to the relative ratio between the first charging and discharging rate and the second charging and discharging rate to control the charging and discharging of the battery cell.

[0084] In step S203, the relative rate between the first charge / discharge rate and the second charge / discharge rate can be the difference between the two charge / discharge rates, a ratio, or a weighted value. The calculation method of the relative rate can be selected according to actual needs, and no specific limitation is made here.

[0085] After calculating the relative rate between two charge / discharge rates, the battery management system can adjust the charge / discharge current of the battery cell based on the relative rate. For example, when the relative rate is small, the charge / discharge current of the battery cell can not be adjusted; when the relative rate is large, the charge / discharge current of the battery cell can be adjusted by multiple gradual adjustments.

[0086] It should be noted that the charging and discharging control of the battery cell is achieved by using the relative ratio between the first and second charging and discharging rates. The appropriate adjustment strategy is selected based on the magnitude of the relative ratio to reduce the risk of battery cell abnormalities caused by drastic changes in the charging and discharging current, thereby improving the reliability and safety of battery cell control.

[0087] In this embodiment, the battery management system charges and discharges the battery cell according to the adjusted charge and discharge current. The adjusted charge and discharge current is obtained by adjusting the charge and discharge rate determined by the electrochemical impedance and state data of the battery cell. This process takes into account the internal state of the battery cell. Therefore, by controlling the charge and discharge of the battery cell based on the adjusted charge and discharge current, the charge and discharge control accuracy of the battery cell can be improved, thereby improving the performance of the battery cell and extending its service life.

[0088] Based on the scheme defined in steps S201 to S203 above, it can be seen that the first charge / discharge rate is a charge / discharge rate determined based on the charge / discharge current and the cell capacity. It cannot reflect the internal state of the cell, and directly using the first charge / discharge rate to control the cell's charge / discharge results in low charge / discharge control accuracy. However, the cell's electrochemical impedance changes with the cell's SOC, temperature, etc., and can reflect the electrochemical reactions inside the cell. In this embodiment, the second charge / discharge rate is determined based on the relationship between the electrochemical impedance and the charge / discharge rate, rather than the overall internal resistance of the cell. The second charge / discharge rate matches the actual state of the cell. Therefore, controlling the cell's charge / discharge current through the relative ratio between the first and second charge / discharge rates allows for more precise cell control, thereby improving the charge / discharge control accuracy of the cell.

[0089] Therefore, the solution provided in this application embodiment controls the charging and discharging of the battery cell based on the charge and discharge rate determined by the electrochemical impedance of the battery cell, which can improve the charging and discharging control accuracy of the battery cell.

[0090] The implementation process of the method provided in the embodiments of this application is described below.

[0091] In some embodiments, the battery management system can acquire electrochemical impedance spectroscopy (EIS) through an EIS detection circuit. Specifically, the battery management system acquires the cell state data and impedance spectrum of each cell in the battery pack, and then obtains the electrochemical impedance corresponding to the cell state data of all cells from the impedance spectrum.

[0092] In the above embodiments, impedance spectroscopy is used to characterize the correlation between cell state data constructed under the usage state and electrochemical impedance, wherein the usage state includes the resting state, the charging state, or the discharging state.

[0093] It should be noted that, in the embodiments of this application, the impedance spectrum is obtained by the electrical device by acquiring the electrochemical impedance of the battery cell and constructing the correlation between the battery cell state data and the electrochemical impedance. That is, the impedance spectrum in the embodiments of this application is obtained by detection in the application scenario, rather than by experimental measurement in the laboratory.

[0094] Since the impedance spectrum in this embodiment is constructed in the electrical equipment, the impedance spectrum can match the actual usage state of the electrical equipment. Therefore, in the charging and discharging control of the battery cell, the impedance spectrum is used to determine the charging and discharging rate of the battery cell and adjust the charging and discharging current. Based on the adjusted charging and discharging current, the charging and discharging control of the battery cell can be performed, which can improve the control accuracy of the charging and discharging of the battery cell.

[0095] In one example Figure 4A schematic diagram of the electrical equipment is shown, consisting of... Figure 4 As can be seen, in this embodiment of the application, the electrical device 300 may include a battery pack 200, which includes a battery management system 100 and battery cells 70. The battery management system 100 is used to detect the electrochemical impedance of the battery cells. Figure 4 As shown, the battery management system 100 includes a processor 20, an excitation source 30, a rectifier 40, a current acquisition chip 50, and a current adjustment circuit 60.

[0096] An excitation source 30, connected to the battery cell 70, is used to output excitation current to the battery cell. This excitation source can be a signal generator, which can generate AC signals of different frequencies to excite the battery cell, so that the processor connected to the battery cell can detect the impedance data of the battery cell.

[0097] It should be noted that each battery cell has a corresponding excitation source, and one excitation source excites one battery cell, or multiple battery cells can be excited simultaneously. In the embodiments of this application, to improve the accuracy of electrochemical impedance detection, an excitation source is set for each battery cell.

[0098] A current acquisition chip 50, connected to the battery cell 70, is used to acquire the charging and discharging current of the battery cell and the excitation current output by the excitation source. The current acquisition chip can be deployed in... Figure 1 The data acquisition circuit 10 can be, but is not limited to, a current sensor. A rectifier 40 is deployed in the circuit loop where the battery cell is located, which can provide charging and discharging current for the battery cell.

[0099] When the battery cell is in a static state, the AC current output by the excitation source (i.e., the excitation current) excites the battery cell alone. When the battery cell is in a charging or discharging state, the charging and discharging current of the battery cell and the excitation current of the excitation source jointly excite the battery cell. That is, the charging and discharging current of the battery cell and the excitation current of the excitation source are superimposed. The superimposed current is used to excite the battery cell. Thus, the processor obtains the voltage and current data of the battery cell under excitation. Then, the voltage and current data are processed by fast Fourier transform to obtain the impedance data of the battery cell.

[0100] By adjusting the cell state data within a preset range and repeating the above process, multiple sets of cell state data and electrochemical impedance can be obtained. By constructing the correlation between the multiple sets of cell state data and electrochemical impedance, the impedance spectrum of the cell can be obtained.

[0101] It should be noted that the above preset range is the range that allows the battery cell to be used normally. For example, the SOC of the battery cell is between 3% SOC and 100% SOC, and the battery cell temperature is between -20℃ and 45℃.

[0102] Furthermore, it should be noted that when the battery cell is in a charging or discharging state, the excitation of the cell comes from the excitation current output by the excitation source and the charging / discharging current of the cell. If the ratio between the excitation current and the charging / discharging current is not set appropriately, the cell may fail to be excited, thereby affecting the accuracy of the cell's electrochemical impedance detection. Based on this, in this embodiment, a current adjustment circuit is also deployed in the battery management system. This current adjustment circuit can adjust the amplitude of the excitation current and / or the amplitude of the charging / discharging current to ensure that the superimposed current is within a reasonable range, thus enabling the cell to be excited.

[0103] This completes the construction of the cell's impedance spectrum. After the impedance spectrum is constructed, the battery management system can use it in conjunction with the cell's state-of-the-art data to determine the cell's electrochemical impedance, and then use this electrochemical impedance to determine the cell's charge / discharge rate.

[0104] In some embodiments, Figure 5 The method for determining the first charge / discharge rate is shown, such as... Figure 5 As shown, the method includes steps S501 to S503:

[0105] Step S501: Obtain the electrochemical impedance of all cells in the battery pack;

[0106] Step S502: Identify outlier cells from all cells based on the electrochemical impedance of each cell in the battery pack.

[0107] Step S503: Obtain the first charge / discharge rate of the outlier cell based on the charge / discharge current and cell capacity of the outlier cell.

[0108] In the above embodiments, an outlier cell is a cell in the battery pack whose electrochemical impedance deviates from that of other cells by a predetermined threshold.

[0109] It's important to note that a battery cell is a chemical system. With sufficient side reactions, the cell can become polarized, leading to increased charge transfer impedance. Higher charge transfer impedance results in lower power output and a smaller current output. If the charge / discharge current is too low, the battery management system will trigger an undervoltage warning, directly disconnecting the cell from the device and causing a power outage, thus affecting the device's operation. Therefore, it's necessary to detect cells in the battery pack with charge transfer impedance exceeding a preset threshold—these are known as outlier cells—and adjust their charge / discharge rates to keep them within a reasonable range, reducing the risk of power outages.

[0110] In addition, a battery pack usually contains multiple cells, but not all cells require charging and discharging current adjustment. Therefore, before controlling the charging and discharging of the cells in the battery pack, the battery management system can first identify the outlier cells in the battery pack and then control the charging and discharging of the outlier cells, which can improve the efficiency of cell charging and discharging control.

[0111] Furthermore, after identifying the outlier cells in the battery pack, the battery management system collects the charging and discharging current and nominal capacity of the outlier cells, and then uses formula (1) to calculate the first charge and discharge rate of the outlier cells.

[0112] In some embodiments, out-of-systems cells may be employed. Figure 6 The method shown is used to determine this, that is, step S502 includes the following steps S5021 to S5023:

[0113] Step S5021: Determine the impedance threshold based on the electrochemical impedance of all cells.

[0114] Step S5022: Determine the impedance deviation of each cell based on the relative value between the electrochemical impedance and the impedance threshold of each cell in the battery pack.

[0115] Step S5023: Identify cells whose impedance deviation is greater than a preset threshold from all cells to obtain outlier cells.

[0116] In the above embodiments, the impedance threshold can be any one of the median, mean, median, and mode of all cells in the battery pack. Alternatively, the obtained impedance threshold can be weighted according to the usage state of the cells; for example, the weighting coefficient is A1 during charging, A2 during discharging, and A3 during rest.

[0117] In the above embodiments, electrochemical impedance includes charge transfer impedance. The relative value between electrochemical impedance and the threshold can be the difference or ratio between charge transfer impedance and the impedance threshold. As can be seen from the above, when the charge transfer impedance of the battery cell is higher than the impedance threshold, there is a risk of power outage for the electrical equipment. Therefore, in the embodiments of this application, the aforementioned impedance deviation can be the degree to which the charge transfer impedance is higher than the impedance threshold.

[0118] For example, the battery management system calculates the median of the charge transfer impedance of all cells in the battery pack as an impedance threshold; then, it calculates the difference between the charge transfer impedance of each cell and the impedance threshold to obtain the impedance deviation degree; cells with an impedance deviation degree greater than a preset threshold are identified as outlier cells. Furthermore, when the battery management system detects the presence of outlier cells in the battery pack, it begins to execute the cell charge / discharge control method provided in this application embodiment.

[0119] As can be seen from steps S5021 to S5023 above, in this embodiment of the application, the impedance threshold is determined by the electrochemical impedance of all cells, and is not a fixed value. This allows the determination of the impedance threshold to be adapted to the working state of the cells in the battery pack, and thus the outlier cells in the battery pack can be located quickly and accurately based on the impedance threshold.

[0120] In some embodiments, Figure 7 The method for determining the second charge / discharge rate is shown, such as... Figure 7 As shown, the method includes steps S701 to S702:

[0121] Step S701: Obtain the preset correlation between cell impedance, cell status, and charge / discharge rate;

[0122] Step S702: Determine the second charge / discharge rate corresponding to the electrochemical impedance and cell state data from the preset correlation relationship.

[0123] It should be noted that the internal structure of a battery cell is an electrochemical system. The ohmic impedance of the battery cell is generally affected by the hardware environment, but not by the internal chemical reactions. Therefore, in this embodiment, the influence of the ohmic impedance of the battery cell on the charge / discharge rate can be disregarded. However, charge transfer impedance can reflect the internal electrochemical reactions of the battery cell. Therefore, in this embodiment, a correlation is established between charge transfer impedance and charge / discharge rate.

[0124] In steps S701 to S702, the aforementioned preset correlation can be obtained through testing in a laboratory setting. For example, in a laboratory setting, the charging and discharging current of the battery cell is varied at different SOC and temperatures to obtain multiple sets of data. Each set of data includes the charge transfer impedance of the battery cell at the corresponding SOC and temperature, as well as the charge / discharge rate corresponding to the charging and discharging current. Then, existing data fitting algorithms can be used to fit the multiple sets of data to obtain the aforementioned preset correlation. By plotting the curve corresponding to the preset correlation, the following can be obtained: Figure 3 The graph shown has the charge / discharge rate on the horizontal axis and the charge transfer impedance on the vertical axis.

[0125] In addition, the aforementioned preset correlation can also be detected in electrical devices. For example, in automotive applications, the battery management system detects the electrochemical impedance of the battery cells in the vehicle and collects data such as the cell temperature, SOC, and charging / discharging current. Then, by fitting the collected data, the aforementioned preset correlation can be obtained.

[0126] It should be noted that, as can be seen from the above, the preset correlation is determined by the cell impedance, cell state, and cell charge / discharge rate. Therefore, the second charge / discharge rate obtained based on this preset correlation is more consistent with the actual state of the cell, laying the foundation for precise control of subsequent cell charge / discharge.

[0127] In some embodiments, to achieve precise control of cell charging and discharging, the battery management system can also adjust the aforementioned preset correlation relationships. Specifically, such as... Figure 8 As shown, adjusting the preset association relationship may include steps S801 to S802:

[0128] Step S801: Obtain the historical electrochemical impedance and historical charge / discharge rate of the battery cell under the historical operating conditions of the electrical equipment.

[0129] Step S802: Adjust the preset correlation relationship based on the historical electrochemical impedance and historical charge / discharge rate to obtain the adjusted preset correlation relationship.

[0130] In steps S801 to S802 above, the historical cell impedance and historical charge / discharge rate of the battery cell can be the cell impedance and charge / discharge rate under normal operating conditions of the electrical equipment. For example, the historical cell impedance is the charge transfer impedance with an impedance value less than the impedance threshold, and the historical charge / discharge rate is the charge / discharge rate of the battery cell at a reasonable temperature and SOC.

[0131] Moreover, in the above embodiments, the historical electrochemical impedance and historical charge / discharge rate are determined based on the historical operating status of the electrical equipment. That is, the historical operating data of the electrical equipment are also considered in the process of adjusting the preset correlation, so that the adjusted preset correlation can be adapted to the electrical equipment. Then, the charging and discharging of the battery cell can be controlled based on the adjusted preset correlation, which can not only improve the control accuracy of the charging and discharging of the battery cell, but also optimize the performance of the battery cell in the electrical equipment and extend the service life of the battery cell.

[0132] In some embodiments, the battery management system can be based on Figure 9 The method for adjusting the preset correlation shown is used to adjust the correlation between electrochemical impedance and charge / discharge rate. Specifically, the method includes the following steps S8021 to S8022:

[0133] Step S8021: Obtain the fourth charge / discharge rate corresponding to the historical electrochemical impedance from the preset correlation relationship;

[0134] Step S8022: Adjust the preset correlation relationship based on the relative value between the historical charge / discharge rate and the fourth charge / discharge rate to obtain the adjusted preset correlation relationship.

[0135] For example, the relative value between the historical charge / discharge rate and the fourth charge / discharge rate can be a difference, a ratio, etc. Taking the difference as an example, if the relative value between the historical charge / discharge rate and the fourth charge / discharge rate is small, no adjustment is needed; if the relative value between the historical charge / discharge rate and the fourth charge / discharge rate is large, then the historical operating status of the electrical equipment should be considered. If the electrical equipment is in normal operating condition, the average of the historical charge / discharge rate and the fourth charge / discharge rate can be used as the adjusted charge / discharge rate; if the electrical equipment is in abnormal operating condition, there is no need to adjust the preset correlation.

[0136] In addition, during adjustment, the adjustment strategy can be determined based on the relative value between the historical charge / discharge rate and the fourth charge / discharge rate. For example, if the relative value is large, the number of times the charge / discharge rate occurs under the same cell state data and electrochemical impedance can be counted. That is, the first count of the charge / discharge rate that is small in difference from the historical charge / discharge rate and the second count of the charge / discharge rate that is small in difference from the fourth charge / discharge rate can be counted. The first weight value corresponding to the historical charge / discharge rate and the second weight value corresponding to the fourth charge / discharge rate can be determined based on the first count and the second count, respectively. Then, the first weight value, the historical charge / discharge rate, the second weight value and the fourth charge / discharge rate are weighted and calculated, and the obtained charge / discharge rate is used to adjust the preset correlation relationship.

[0137] It should be noted that by adjusting the preset correlation relationship through the relative value between the historical charge / discharge rate and the fourth charge / discharge rate, the adjusted preset correlation relationship can be made to match the actual state of the electrical equipment, laying the foundation for precise control of battery cell charge / discharge.

[0138] In some embodiments, after obtaining the first charge / discharge rate and the second charge / discharge rate of the outlier cell, the battery management system can control the charge / discharge of the cell based on the relative rates between the two. For example... Figure 10 As shown, the method includes the following steps S1001 to S1003:

[0139] Step S1001: When the relative rate is greater than the first rate threshold, the charge and discharge rate of the outlier cell is adjusted to obtain the adjusted charge and discharge rate.

[0140] Step S1002: Determine the adjusted charge / discharge current based on the adjusted charge / discharge rate and the cell capacity of the outlier cell.

[0141] Step S1003: Control the charging and discharging of the battery cell by adjusting the charging and discharging current.

[0142] In the above embodiments, the first rate threshold can be determined based on the historical usage conditions of the battery cells in the electrical equipment. For example, if the vehicle is frequently in long-distance operation, the first rate threshold can be set to a larger value.

[0143] In the above embodiments, if the relative rate is greater than the first rate threshold, it indicates that the difference between the first rate threshold and the second rate threshold is large. At this time, it is necessary to adjust the charge and discharge rate of the battery cell to reduce the difference between the adjusted charge and discharge rate and the second rate threshold, thereby improving the control accuracy of the battery cell's charge and discharge and optimizing the charge and discharge performance of the battery cell.

[0144] If the relative rate is less than or equal to the first rate threshold, it indicates that the difference between the first rate threshold and the second rate threshold is small. In this case, the charging and discharging performance of the battery cell is good, and there is no need to adjust the charging and discharging rate.

[0145] In this embodiment, when the relative charge / discharge rate is greater than a first charge / discharge rate threshold, it can be determined that the charge / discharge rate of the outlier cell needs to be adjusted. At this time, the battery management system can determine the adjustment strategy for the charge / discharge rate based on the degree of difference between the first and second charge / discharge rates.

[0146] In some embodiments, when the relative rate is greater than a first rate threshold and less than a second rate threshold, the first charge / discharge rate of the outlier cell is adjusted to a second charge / discharge rate, wherein the first rate threshold is less than the second rate threshold.

[0147] In this embodiment of the application, when it is determined that the charge and discharge rate of the outlier cell needs to be adjusted, but the difference between the first charge and discharge rate and the second charge and discharge rate can be adjusted once so that the relative rate is less than the first rate threshold, the first charge and discharge rate of the outlier cell can be directly adjusted to the second charge and discharge rate, and the second charge and discharge rate can be used to control the charge and discharge of the outlier cell.

[0148] It should be noted that by adjusting the charge / discharge rate of the battery cell to the second charge / discharge rate, and then controlling the charge / discharge of the battery cell at the second charge / discharge rate, the charge / discharge performance of the battery cell can be improved, thereby improving the control accuracy of charge / discharge.

[0149] In some embodiments, when the relative rate is greater than the second rate threshold, the method for adjusting the charge / discharge rate can be as follows: Figure 11 As shown, the method includes the following steps:

[0150] Step S1101: Obtain the adjustment coefficient corresponding to the relative multiplier;

[0151] Step S1102: Determine the adjustment range based on the product of the adjustment coefficient and the relative multiplier;

[0152] Step S1103: Adjust the first charge / discharge rate according to the adjustment range to obtain the third charge / discharge rate, wherein the relative value between the third charge / discharge rate and the second charge / discharge rate is less than the first rate threshold.

[0153] In the above embodiments, the adjustment coefficient, for example, an integer less than 1, can be positively correlated with the relative multiplier; that is, the larger the relative multiplier, the larger the adjustment coefficient. The relationship between the relative multiplier and the adjustment coefficient can be linear or non-linear, and can be set based on practical experience.

[0154] It should be noted that when there is a significant difference between the first and second charge / discharge rates, directly adjusting the first rate to the second would cause a large change in the cell's charge / discharge current, reducing cell performance. Excessive adjustments over a long period may also be ineffective; for example, due to the extended adjustment time, other cells in the battery pack might require further adjustment after the current cell has been adjusted. In this embodiment, however, the adjustment range is determined by an adjustment coefficient corresponding to the relative rate. Based on this range, the charge / discharge rate of outlier cells is adjusted, preventing sudden changes in the cell's charge / discharge current during adjustment, thus improving cell performance. Simultaneously, the adjustment time is not excessive, effectively adjusting the charge / discharge current.

[0155] In some embodiments, such as Figure 12 As shown, step S1103 includes the following steps S1201 to S1202:

[0156] Step S1201: If the first charge / discharge rate is greater than the second charge / discharge rate, increase the first charge / discharge rate by the adjustment range to obtain the third charge / discharge rate.

[0157] In step S1202, if the first charge / discharge rate is less than the second charge / discharge rate, the first charge / discharge rate is reduced by the adjustment range to obtain the third charge / discharge rate.

[0158] Through steps S1201 to S1202, the first charge-discharge rate is adjusted in a manner that tends towards the second charge-discharge rate, so as to improve the control accuracy of the cell's charge-discharge and optimize the cell's charge-discharge performance.

[0159] This concludes the explanation of the methods provided in the embodiments of this application.

[0160] It should be understood that although the steps in the flowcharts of the embodiments described above are shown sequentially according to the arrows, these steps are not necessarily executed in the order indicated by the arrows. Unless explicitly stated herein, there is no strict order restriction on the execution of these steps, and they can be executed in other orders. Moreover, at least some steps in the flowcharts of the embodiments described above may include multiple steps or multiple stages. These steps or stages are not necessarily completed at the same time, but can be executed at different times. The execution order of these steps or stages is not necessarily sequential, but can be performed alternately or in turn with other steps or at least some of the steps or stages of other steps.

[0161] Figure 13 A schematic diagram of the structure of an electronic device provided in one embodiment of this application is shown.

[0162] like Figure 13 The diagram shows an exemplary hardware architecture of an electronic device capable of implementing the cell charging and discharging control method according to the embodiments of this application. This electronic device may refer to the electronic device in the embodiments of this application.

[0163] The electronic device may include a processor 1301 and a memory 1302 storing computer program instructions.

[0164] Specifically, the processor 1301 may include a central processing unit (CPU), an application-specific integrated circuit (ASIC), or one or more integrated circuits that can be configured to implement the embodiments of this application.

[0165] Memory 1302 may include mass storage for data or instructions. For example, and not limitingly, memory 1302 may include a hard disk drive (HDD), floppy disk drive, flash memory, optical disk, magneto-optical disk, magnetic tape, or Universal Serial Bus (USB) drive, or a combination of two or more of these. Where appropriate, memory 1302 may include removable or non-removable (or fixed) media. Where appropriate, memory 1302 may be internal or external to the integrated gateway disaster recovery device. In a particular embodiment, memory 1302 is non-volatile solid-state memory. In a particular embodiment, memory 1302 may include read-only memory (ROM), random access memory (RAM), disk storage media device, optical storage media device, flash memory device, electrical, optical, or other physical / tangible memory storage device. Therefore, typically, memory 1302 includes one or more tangible (non-transitory) computer-readable storage media (e.g., memory devices) encoded with software including computer-executable instructions, and when the software is executed (e.g., by one or more processors), it is operable to perform the operations described with reference to the charge-discharge control method for a battery cell according to this application.

[0166] The processor 1301 reads and executes computer program instructions stored in the memory 1302 to implement the charging and discharging control method of the battery cell in the above embodiment.

[0167] In one example, the electronic device may also include a communication interface 1303 and a bus 1304. Wherein, as... Figure 13 As shown, the processor 1301, memory 1302, and communication interface 1303 are connected through bus 1304 and complete communication with each other.

[0168] The communication interface 1303 is mainly used to realize communication between various modules, devices, units and / or equipment in the embodiments of this application.

[0169] Bus 1304 includes hardware, software, or both, that couples components of an electronic device together. For example, and not limitingly, the bus may include an Accelerated Graphics Port (AGP) or other graphics bus, an Enhanced Industry Standard Architecture (EISA) bus, a Front Side Bus (FSB), HyperTransport (HT) interconnect, an Industry Standard Architecture (ISA) bus, an Infinite Bandwidth Interconnect, a Low Pin Count (LPC) bus, a memory bus, a Microchannel Architecture (MCA) bus, a Peripheral Component Interconnect (PCI) bus, a PCI-Express (PCI-X) bus, a Serial Advanced Technology Attachment (SATA) bus, a Video Electronics Standards Association Local (VLB) bus, or other suitable buses, or combinations of two or more of these. Where appropriate, bus 1304 may include one or more buses. Although specific buses are described and illustrated in embodiments of this application, any suitable bus or interconnect is contemplated herein.

[0170] In one embodiment, this application also provides a readable storage medium storing computer program instructions, which, when executed by a processor, implement the above-described battery cell charging and discharging control method.

[0171] In one embodiment, this application also provides a computer program product in which the instructions, when executed by the processor of an electronic device, cause the electronic device to perform the above-described battery cell charging and discharging control method.

[0172] It should be clarified that this application is not limited to the specific configurations and processes described above and shown in the figures. For the sake of brevity, detailed descriptions of known methods are omitted here. In the above embodiments, several specific steps are described and shown as examples. However, the method process of this application is not limited to the specific steps described and shown. Those skilled in the art can make various changes, modifications, and additions, or change the order of steps, after understanding the spirit of this application.

[0173] The functional blocks shown in the above block diagram can be implemented as hardware, software, firmware, or a combination thereof. When implemented in hardware, they can be, for example, electronic circuits, application-specific integrated circuits (ASICs), appropriate firmware, plug-ins, function cards, etc. When implemented in software, the elements of this application are programs or code segments used to perform the required tasks. Programs or code segments can be stored on a machine-readable medium or transmitted over a transmission medium or communication link via data signals carried on a carrier wave. "Machine-readable medium" can include any medium capable of storing or transmitting information. Examples of machine-readable media include electronic circuits, semiconductor memory devices, ROM, flash memory, erasable ROM (EROM), floppy disks, CD-ROMs, optical disks, hard disks, fiber optic media, radio frequency (RF) links, etc. Code segments can be downloaded via computer networks such as the Internet, intranets, etc.

[0174] It should also be noted that the exemplary embodiments mentioned in this application describe methods or systems based on a series of steps or apparatus. However, this application is not limited to the order of the above steps; that is, the steps can be performed in the order mentioned in the embodiments, or in a different order, or several steps can be performed simultaneously.

[0175] The above description, with reference to flowchart illustrations and / or block diagrams of a cell charging / discharging control method, battery management system, battery pack, and device according to embodiments of this application, illustrates various aspects of the present application. It should be understood that each block in the flowchart illustrations and / or block diagrams, and combinations thereof, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, or other programmable data processing apparatus to create a machine such that these instructions, executable by the processor of the computer or other programmable data processing apparatus, enable the implementation of the functions / actions specified in one or more blocks of the flowchart illustrations and / or block diagrams. Such a processor may be, but is not limited to, a general-purpose processor, a special-purpose processor, a special application processor, or a field-programmable logic circuit. It is also understood that each block in the block diagrams and / or flowcharts, and combinations thereof, can also be implemented by dedicated hardware performing the specified functions or actions, or by a combination of dedicated hardware and computer instructions.

[0176] 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 charge-discharge control method of an electric power source, characterized by comprising: include: The electrochemical impedance of the cells in the battery pack, the cell state data of the cells, and the first charge / discharge rate corresponding to the charge / discharge current of the cells are obtained. Obtain the second charge / discharge rate corresponding to the electrochemical impedance and the cell state data; The charging and discharging current of the battery cell is adjusted according to the relative ratio between the first charging and discharging rate and the second charging and discharging rate to control the charging and discharging of the battery cell. The method of obtaining the electrochemical impedance of the cells in the battery pack includes: obtaining cell state data and impedance spectrum for each cell in the battery pack, wherein the impedance spectrum is used to characterize the correlation between cell state data constructed under the use state and electrochemical impedance, the use state including the resting state, charging state or discharging state; and obtaining the electrochemical impedance corresponding to the cell state data of all the cells from the impedance spectrum.

2. The method of claim 1, wherein, Obtaining the first charge / discharge rate corresponding to the charge / discharge current of the battery cell includes: Obtain the electrochemical impedance of all cells in the battery pack; Based on the electrochemical impedance of each cell in the battery pack, outlier cells are identified from all the cells, wherein the outlier cell is a cell in the battery pack whose electrochemical impedance deviates from that of other cells by a predetermined threshold. The first charge / discharge rate of the outlier cell is obtained based on the charge / discharge current and the cell capacity of the outlier cell.

3. The method of claim 2, wherein, The step of identifying outlier cells from all cells based on the electrochemical impedance of each cell in the battery pack includes: The impedance threshold is determined based on the electrochemical impedance of all the cells. The degree of impedance deviation of each cell is determined based on the relative value between the electrochemical impedance of each cell in the battery pack and the impedance threshold. The outlier cell is obtained by identifying the cell whose impedance deviation is greater than the preset threshold from all the cells.

4. The method according to claim 2 or 3, characterized in that, The step of adjusting the charging and discharging current of the battery cell based on the relative ratio between the first charging / discharging rate and the second charging / discharging rate, and controlling the charging and discharging of the battery cell, includes: When the relative rate is greater than the first rate threshold, the charge and discharge rate of the outlier cell is adjusted to obtain the adjusted charge and discharge rate. The adjusted charge / discharge current is determined based on the adjusted charge / discharge rate and the cell capacity of the outlier cell. The charging and discharging of the battery cell is controlled by the adjusted charging and discharging current.

5. The method of claim 4, wherein, When the relative rate is greater than a first rate threshold, adjusting the charge / discharge rate of the outlier cell to obtain an adjusted charge / discharge rate includes: When the relative rate is greater than the first rate threshold and less than the second rate threshold, the first charge / discharge rate of the outlier cell is adjusted to the second charge / discharge rate, wherein the first rate threshold is less than the second rate threshold.

6. The method of claim 5, wherein, The method further includes: If the relative multiplier is greater than the second multiplier threshold, an adjustment coefficient corresponding to the relative multiplier is obtained, wherein the adjustment coefficient is positively correlated with the relative multiplier; determine an adjustment range according to a product of the adjustment coefficient and the relative ratio; adjust the first charge-discharge ratio according to the adjustment range to obtain a third charge-discharge ratio, wherein a relative value between the third charge-discharge ratio and the second charge-discharge ratio is less than the first ratio threshold.

7. The method of claim 6, wherein, The adjusting the first charge-discharge ratio according to the adjustment range to obtain a third charge-discharge ratio comprises: in a case that the first charge-discharge ratio is greater than the second charge-discharge ratio, increasing the first charge-discharge ratio according to the adjustment range to obtain the third charge-discharge ratio; and / or, in a case that the first charge-discharge ratio is less than the second charge-discharge ratio, decreasing the first charge-discharge ratio according to the adjustment range to obtain the third charge-discharge ratio.

8. The method of claim 1, wherein, The obtaining the second charge-discharge ratio corresponding to the electrochemical impedance and the battery cell state data comprises: obtaining a preset association relationship among the electrochemical impedance, the battery cell state and the charge-discharge ratio; determining the second charge-discharge ratio corresponding to the electrochemical impedance and the battery cell state data from the preset association relationship.

9. The method of claim 8, wherein, The method further comprises: obtaining a historical electrochemical impedance and a historical charge-discharge ratio of the battery cell under a historical operating state of the electrical equipment; adjusting the preset association relationship according to the historical electrochemical impedance and the historical charge-discharge ratio to obtain an adjusted preset association relationship.

10. The method of claim 9, wherein, The adjusting the preset association relationship according to the historical electrochemical impedance and the historical charge-discharge ratio to obtain an adjusted preset association relationship comprises: obtaining a fourth charge-discharge ratio corresponding to the historical electrochemical impedance from the preset association relationship; adjusting the preset association relationship according to a relative value between the historical charge-discharge ratio and the fourth charge-discharge ratio to obtain the adjusted preset association relationship.

11. A battery management system, characterized by, comprise: a data acquisition circuit configured to obtain an electrochemical impedance of a battery cell in a battery pack, battery cell state data of the battery cell, a first charge-discharge ratio corresponding to a charge-discharge current of the battery cell, and a second charge-discharge ratio corresponding to the electrochemical impedance and the battery cell state data; a processor connected to the data acquisition circuit and configured to adjust the charge-discharge current of the battery cell according to a relative ratio between the first charge-discharge ratio and the second charge-discharge ratio, and control the charge-discharge of the battery cell. The system is further configured to obtain battery cell state data and an impedance spectrum of each battery cell in the battery pack, wherein the impedance spectrum is used to represent an association relationship between battery cell state data and electrochemical impedance constructed in a use state, and the use state comprises a static state, a charging state or a discharging state; and obtain the electrochemical impedance corresponding to the battery cell state data of all the battery cells from the impedance spectrum.

12. A battery pack, characterized by comprise a battery cell and the battery management system of claim 11.

13. An electrical device, characterized by comprise the battery pack of claim 12.

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