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

Abstract

The invention discloses a charging and discharging control method of a battery cell, a battery management system, a battery pack and equipment. The method comprises the following steps: acquiring 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 charge-discharge current of the battery cell; acquiring a second charge-discharge rate corresponding to the electrochemical impedance and the cell state data; and adjusting the charging and discharging current of the battery cell according to the relative multiplying power between the first charging and discharging multiplying power and the second charging and discharging multiplying power, and controlling the charging and discharging of the battery cell. According to the scheme provided by the invention, charging and discharging control is performed on the battery cell according to the charging and discharging rate determined by the electrochemical impedance of the battery cell, so that the charging and discharging control precision of the battery cell can be improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of electrochemistry, and in particular to a charging and discharging control method of an electric core, a battery management system, a battery pack and an equipment. BACKGROUND

[0002] The charging and discharging rate of the electric core has an important influence on the performance of the battery, and if the charging and discharging rate of the electric core is too large or too small, the service life and safety of the electric core will be affected.

[0003] In the related art, a pre-set correlation relationship is usually used to determine the charging and discharging rate of the electric core, and the charging and discharging rate determined in this way does not match the actual state of the electric core. Therefore, how to improve the charging and discharging control precision of the electric core is a problem to be solved at present. SUMMARY

[0004] The present application provides a charging and discharging control method of an electric core, a battery management system, a battery pack and an equipment, which controls the charging and discharging of the electric core according to the charging and discharging rate determined by the electrochemical impedance of the electric core, thereby improving the charging and discharging control precision of the electric core.

[0005] In a first aspect, the present application provides a charging and discharging control method of an electric core, which comprises: obtaining the electrochemical impedance of the electric core, the electric core state data of the electric core and the first charging and discharging rate corresponding to the charging and discharging current of the electric core in a battery pack, the electric core state data comprising the use state, temperature and state of charge of the electric core; obtaining the second charging and discharging rate corresponding to the electrochemical impedance and the electric core state data; adjusting the charging and discharging current of the electric core according to the relative rate between the first charging and discharging rate and the second charging and discharging rate to obtain the adjusted charging and discharging current; and controlling the charging and discharging of the electric core through the adjusted charging and discharging current.

[0006] From the above content, it can be seen that the first charging and discharging rate is the charging and discharging rate determined based on the charging and discharging current and the capacity of the electric core, which cannot reflect the internal state of the electric core, and directly using the first charging and discharging rate to control the charging and discharging of the electric core has the problem of low charging and discharging control precision. The electrochemical impedance of the electric core changes with the SOC, temperature and other factors of the electric core, and can reflect the electrochemical reaction inside the electric core. In the embodiments of the present application, the second charging and discharging rate is determined based on the relationship between the electrochemical impedance and the charging and discharging rate, rather than the internal resistance of the overall electric core. The second charging and discharging rate matches the actual state of the electric core, and therefore, by controlling the charging and discharging current of the electric core through the relative rate between the first charging and discharging rate and the second charging and discharging rate, the electric core can be controlled more accurately, thereby improving the charging and discharging control precision of the electric core.

[0007] Therefore, the scheme provided in the embodiments of the present application can improve the charging and discharging control precision of the battery cell by controlling the charging and discharging of the battery cell according to the charging and discharging rate determined by the electrochemical impedance of the battery cell.

[0008] In some embodiments, the first charging and discharging rate of the battery cell is obtained by: obtaining the electrochemical impedances of all battery cells in the battery pack; determining, from all battery cells, an outlier battery cell according to the electrochemical impedance of each battery cell in the battery pack, wherein the outlier battery cell is a battery cell whose impedance deviation from the electrochemical impedance of other battery cells in the battery pack is greater than a preset threshold; and obtaining the first charging and discharging rate of the outlier battery cell according to the charging and discharging current of the outlier battery cell and the battery cell capacity of the outlier battery cell.

[0009] The outlier battery cell is identified from the battery pack, and the first charging and discharging rate of the outlier battery cell is obtained to control the charging and discharging of the outlier battery cell, which can improve the charging and discharging control efficiency of the battery cells in the battery pack.

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

[0011] The electrochemical impedances of all battery cells are used to determine the impedance threshold, so that the determination of the impedance threshold can be adapted to the working state of the battery cells in the battery pack, and the outlier battery cell in the battery pack can be quickly and accurately located based on the impedance threshold.

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

[0013] When the difference between the first rate threshold and the second rate threshold is large, the charging and discharging rate of the battery cell is adjusted to reduce the difference between the adjusted charging and discharging rate and the second rate threshold, improve the control precision of the charging and discharging of the battery cell, and optimize the charging and discharging performance of the battery cell.

[0014] In some embodiments, when the relative rate is greater than the first rate threshold, the charge-discharge rate of the outlier battery cell is adjusted to obtain an adjusted charge-discharge rate, including: when the relative rate is greater than the first rate threshold and less than a second rate threshold, the first charge-discharge rate of the outlier battery cell is adjusted to a second charge-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 the 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-discharge control method of the battery cell further includes: when the relative rate is greater than the 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 amplitude according to the product of the adjustment coefficient and the relative rate; and adjusting the first charge-discharge rate according to the adjustment amplitude to obtain a 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.

[0017] By determining the adjustment amplitude through the adjustment coefficient corresponding to the relative rate, and then adjusting the charge-discharge rate of the outlier battery cell based on the adjustment amplitude, the charge-discharge current of the battery cell will not change abruptly during the adjustment process, which improves the performance of the battery cell. At the same time, the adjustment time will not be too long, which can achieve the effect of adjusting the charge-discharge current.

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

[0019] Adjusting the first charge-discharge rate in a manner tending to the second charge-discharge rate can improve the control accuracy of the charge-discharge of the battery cell and optimize the charge-discharge performance of the battery cell.

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

[0021] Since the impedance map in the embodiment of the present application is constructed in the electrical equipment, the impedance map can be consistent with the actual use state of the electrical equipment, so that in the charge and discharge control of the battery cell, the impedance map is used to determine the electrochemical impedance of the battery cell, and then the charge and discharge rate is determined and the charge and discharge current is adjusted, and the battery cell is controlled based on the adjusted charge and discharge current, which can improve the control precision of the battery cell charge and discharge.

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

[0023] Since the above-mentioned preset association relationship is determined by the battery cell impedance, the battery cell state and the charge and discharge rate of the battery cell, the second charge and discharge rate obtained based on the preset association relationship is more matched with the actual state of the battery cell, which lays a foundation for the accurate control of the battery cell charge and discharge.

[0024] In some embodiments, the battery cell charge and discharge control method further comprises: obtaining the historical electrochemical impedance and the historical charge and discharge rate of the battery cell under the historical running state of the electrical equipment; and adjusting the preset association relationship according to the historical electrochemical impedance and the historical charge and discharge rate to obtain an adjusted preset association relationship.

[0025] In the process of adjusting the preset association relationship, the historical running data of the electrical equipment is also considered, so that the adjusted preset association relationship can be adapted to the electrical equipment, and then the charge and discharge of the battery cell is controlled based on the adjusted preset association relationship, which can improve the control precision of the battery cell charge and discharge.

[0026] In some embodiments, adjusting the preset association relationship according to the historical electrochemical impedance and the historical charge and discharge rate to obtain an adjusted preset association relationship comprises: obtaining a fourth charge and discharge rate corresponding to the historical electrochemical impedance from the preset association relationship; and adjusting the preset association relationship according to the relative value between the historical charge and discharge rate and the fourth charge and discharge rate to obtain an adjusted preset association relationship.

[0027] By adjusting the preset association relationship according to the relative value between the historical charge and discharge rate and the fourth charge and discharge rate, the adjusted preset association relationship can be consistent with the actual state of the electrical equipment, which lays a foundation for the accurate control of the battery cell charge and discharge.

[0028] In a second aspect, the application also provides a battery management system, comprising: a data acquisition circuit configured to acquire electrochemical impedance of a battery cell in a battery pack, battery cell state data of the battery cell, a first charge-discharge rate corresponding to a charge-discharge current of the battery cell, and a second charge-discharge rate corresponding to the electrochemical impedance and the battery cell state data, the battery cell state data comprising a usage state, a temperature, and a state of charge of the battery cell; and a processor connected to the data acquisition circuit, configured to adjust 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, to obtain an adjusted charge-discharge current, and to control charge-discharge of the battery cell through the adjusted charge-discharge current.

[0029] In a third aspect, the application provides a battery pack, comprising a battery cell and the battery management system according to the second aspect.

[0030] In a fourth aspect, the application provides a power consumption device, comprising the battery pack according to the third aspect.

[0031] The above description is only a summary of the technical solutions of the application. In order to enable the technical means of the application to be more clearly understood, and to be implemented according to the content of the description, and in order to enable the above and other purposes, characteristics and advantages of the application to be more apparent and easy to understand, the specific implementation manner of the application is described below. BRIEF DESCRIPTION OF DRAWINGS

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

[0033] Figure 1 Structure diagram of a battery management system according to an embodiment of the application; Figure 2 Flow diagram of a charge-discharge control method of a battery cell according to an embodiment of the application; Figure 3 Relationship curve between charge transfer impedance and charge-discharge rate of a battery cell according to an embodiment of the application; Figure 4 Structure diagram of a power consumption device according to an embodiment of the application; Figure 5 Flow diagram of a determination method of a first charge-discharge rate according to an embodiment of the application; Figure 6 Flow diagram of a determination method of an outlier battery cell according to an embodiment of the application; Figure 7 Flow diagram of a determination method of a second charge-discharge rate according to an embodiment of the application; Figure 8 Flow diagram of a method for adjusting a preset correlation according to an embodiment of the application; Figure 9 A flowchart of a method for adjusting a preset association relationship according to an embodiment of the present application; Figure 10 A flowchart of a method for controlling charging and discharging of a battery cell according to an embodiment of the present application; Figure 11 A flowchart of a method for adjusting a charging and discharging rate according to an embodiment of the present application; Figure 12 A flowchart of a method for adjusting a charging and discharging rate according to an embodiment of the present application; Figure 13 A structural diagram of an electronic device according to another embodiment of the present application.

[0034] In the drawings, the drawings are not necessarily drawn according to the actual proportions. DETAILED DESCRIPTION

[0035] To make the objectives, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only some of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative work fall within the scope of the present application.

[0036] 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 the present application belongs; the terminology used herein is for the purpose of describing the particular embodiments only and is not intended to be limiting of the present application; the description and the claims of the present application and the above description of drawings, the terms "comprising" and "having" and any variations thereof are intended to cover not exclusively containing.

[0037] In the description of the embodiments of the present application, the technical terms "first", "second", and the like are only used to distinguish different objects, and cannot be understood as indicating or implying relative importance or implicitly indicating the number, specific order or primary and secondary relationship of the indicated technical features. In the description of the embodiments of the present application, the meaning of "a plurality of" is two or more, unless otherwise explicitly and specifically limited.

[0038] In the embodiments of the present application, the reference to "embodiments" means that the specific features, structures or properties described in conjunction with the embodiments can be included in at least one embodiment of the present application. The appearance of this phrase at various places in the specification does not necessarily mean the same embodiment, nor is it an independent or alternative embodiment to other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described in the embodiments of the present application can be combined with other embodiments.

[0039] In the description of the embodiments of the present application, the term "and / or" is merely an association relationship of the associated objects, which means that there can be three relationships, for example, A and / or B, which can represent the three cases of A alone, A and B together, and B alone. In addition, the character " / " herein generally represents an "or" relationship between the associated objects before and after it.

[0040] In the description of the embodiments of the present application, the term "a plurality of" refers to two or more (including two), and similarly, "a plurality of groups" refers to two or more groups (including two groups), and "a plurality of pieces" refers to two or more pieces (including two pieces).

[0041] In the description of the embodiments of the present application, the technical terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the embodiments of the present application and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the embodiments of the present application.

[0042] In the description of the embodiments of the present application, unless otherwise explicitly specified and limited, the technical terms "mounting", "connection", "connection", "fixing" and the like should be understood broadly, for example, it can be fixedly connected, or it can be detachably connected, or it can be integrated; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium; it can be the internal communication of two elements or the interaction relationship between two elements. For those skilled in the art, the specific meanings of the above terms in the embodiments of the present application can be understood according to the specific circumstances.

[0043] The charge and discharge rate refers to the maximum charge and discharge rate of the battery cell per unit time, which is usually expressed in multiples. The charge and discharge rate of the battery cell has an important influence on the charge and discharge control of the battery cell. For example, at a high rate, excessive heat is generated inside the battery cell, causing the temperature inside the battery cell to rise, and the internal resistance of the battery cell to change, which not only affects the charge and discharge of the battery cell, but also affects the service life and safety of the battery cell. Therefore, in order to improve the control accuracy of the charge and discharge of the battery cell and prolong the service life of the battery cell, a suitable charge and discharge rate needs to be set for the battery cell.

[0044] In the related art, the use experience of the battery cell is usually used to determine the charge-discharge rate of the battery cell. For example, there is a certain correlation between the internal resistance of the battery cell and the charge-discharge rate, and the internal resistance of the battery cell is related to the manufacturing process of the battery cell. By recording the charge-discharge rate and the internal resistance of the battery cell in different battery cell specifications provided on the market, the correlation coefficient is calculated, and the current charge-discharge rate of the battery cell is calculated. However, in the related art, the internal resistance of the battery cell is determined by the current and voltage flowing into the battery cell, and the changes inside the battery cell are not considered. However, in actual application, there are electrochemical reactions inside the battery cell, and the electrochemical impedance changes with the temperature, SOC (State Of Charge, state of charge) and other factors of the battery cell. Therefore, if the internal resistance of the battery cell determined by the current and voltage flowing into the battery cell is used to determine the charge-discharge rate of the battery cell, the accuracy is low.

[0045] Therefore, in the related art, the internal state of the battery cell is not considered in the process of determining the charge-discharge rate of the battery cell, which makes the determined charge-discharge rate inconsistent with the actual state of the battery cell, and further using the charge-discharge rate to control the charge and discharge of the battery cell will reduce the accuracy of the charge and discharge control of the battery cell.

[0046] To solve the problems existing in the prior art, the embodiments of the present application provide a battery cell charge-discharge control method, a battery management system, a battery pack and a device. In the embodiments of the present application, the battery management system can control the charge and discharge of the battery cell every certain period of time, or adjust the charge-discharge rate of the battery cell when detecting that the electrochemical impedance of the battery cell does not meet the preset condition (for example, the charge transfer impedance of the battery cell is greater than the set impedance threshold), to realize the control of the charge and discharge of the battery cell.

[0047] Specifically, in the embodiments of the present application, the battery management system calculates a first charge-discharge rate of the battery cell according to the charge-discharge current of the battery cell and the capacity of the battery cell, and determines a second charge-discharge rate from the correlation between the electrochemical impedance and the charge-discharge rate according to the electrochemical impedance of the battery cell and the state data of the battery cell. However, whether to adjust the charge-discharge current of the battery cell is determined according to the relative rate between the first charge-discharge rate and the second charge-discharge rate, and if adjustment is needed, the specific amplitude of the adjustment is determined, so that the battery cell can be charged and discharged with reasonable charge-discharge current, and the accuracy of the charge and discharge control of the battery cell is improved.

[0048] In one embodiment, Figure 1 The structure schematic diagram of the battery management system provided by the embodiments of the present application is shown, which comprises a data acquisition circuit 10 and a processor 20. Figure 1 It can be seen that in the embodiments of the present application, the battery management system at least comprises a data acquisition circuit 10 and a processor 20.

[0049] In the embodiment of the present application, the data acquisition circuit 10 can include an electrical signal collector (for example, a voltage collector, a current collector, a temperature sensor, etc.) for acquiring the electrochemical impedance of the battery cell in the battery pack, the cell state data of the battery cell, the first charge-discharge rate corresponding to the charge-discharge current of the battery cell, and the second charge-discharge rate corresponding to the electrochemical impedance and the cell state data.

[0050] In the embodiment of the present application, the electrochemical impedance of the battery cell is an alternating current impedance, which can include an ohmic impedance, a charge transfer impedance, and a membrane impedance of the battery cell. The charge transfer impedance of the battery cell reflects the resistance of charge transfer during the charge-discharge process of the battery cell, which directly affects the energy conversion efficiency and output stability. Moreover, a higher charge transfer impedance can accelerate the aging of the electrode material in the battery cell and shorten the cycle life of the battery cell. Therefore, in the embodiment of the present application, the battery management system mainly implements the charge-discharge control of the battery cell based on the charge transfer impedance of the battery cell, that is, in the embodiment of the present application, the electrochemical impedance mainly refers to the charge transfer impedance of the battery cell.

[0051] In the above embodiment, the battery management system also deploys an EIS (Electrochemical Impedance Spectroscopy) detection circuit, which is connected with the battery cell and the data acquisition circuit. The EIS detection circuit can detect the electrochemical impedance of the battery cell in the electrical equipment and transmit the detected electrochemical impedance to the data acquisition circuit.

[0052] In the embodiment of the present application, the cell state data can include the use state of the battery cell, the SOC of the battery cell, the temperature of the battery cell, etc. The use state of the battery cell can include a static state, a charging state, or a discharging state.

[0053] In the embodiment of the present application, 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 from the pre-set correlation relationship according to the electrochemical impedance, which can be used as a charge-discharge rate reference to adjust the charge-discharge current of the battery cell. The above-mentioned correlation relationship is a pre-constructed correlation relationship between the impedance of the battery cell and the charge-discharge rate.

[0054] For the processor 20, in the embodiment of the present application, the processor 20 is connected with the data acquisition circuit, and is configured to adjust the charge-discharge current of the battery cell according to the relative rate between the first charge-discharge rate and the second charge-discharge rate, and control the charge-discharge of the battery cell.

[0055] It should be noted that, in the embodiments of the present application, the second charge-discharge rate is determined by the electrochemical impedance of the battery cell and the battery cell state data, and the electrochemical impedance can reflect the internal state of the battery cell, therefore, the process of using the relative ratio between the first charge-discharge rate and the second charge-discharge rate to control the charge and discharge of the battery cell takes into account the internal state of the battery cell, and the control of the charge and discharge of the battery cell in this way can effectively improve the charge and discharge performance of the battery cell and prolong the service life of the battery cell. Moreover, compared with the prior art, the charge and discharge control of the battery cell is more accurate.

[0056] In addition, in the embodiments of the present application, the relative ratio between the first charge-discharge rate and the second charge-discharge rate is used to realize the charge and discharge control of the battery cell, and the appropriate adjustment strategy is selected according to the size of the relative ratio, thereby reducing the risk of sudden change of the charge and discharge current of the battery cell, leading to abnormality of the battery cell, and improving the reliability and safety of the battery cell control.

[0057] At this point, the introduction of the battery management system provided by the embodiments of the present application is completed.

[0058] The following takes the battery management system as the execution subject to introduce the charge and discharge control method of the battery cell provided by the embodiments of the present application.

[0059] In one embodiment, Figure 2 A flowchart of the charge and discharge control method of the battery cell is shown, and the method can be applied to the battery management system. As Figure 2 shown, the method can include the following steps S201 to S203: Step S201, obtaining the electrochemical impedance of the battery cell in the battery pack, the battery cell state data of the battery cell, and the first charge-discharge rate corresponding to the charge and discharge current of the battery cell.

[0060] In step S201, the battery pack can be deployed in a power consumption device, for example, a new energy vehicle, a battery replacement station, etc., and the battery pack can include a plurality of battery cells. In the embodiments of the present application, a battery management system is provided in the power consumption device, which is connected with the battery pack and used for managing, performance analyzing, and abnormality detecting the battery cells in the battery pack. A data acquisition circuit is deployed in the battery management system, which can obtain the electrochemical impedance of the battery cell, the battery cell state data, the first charge-discharge rate of the battery cell, etc.

[0061] It should be noted that the electrochemical impedance can include the ohmic impedance, charge transfer impedance, membrane impedance, etc. of the battery cell, and in the embodiments of the present application, the charge transfer impedance is taken as an example for explanation.

[0062] In step S201, the battery cell state data includes the use state (for example, the charge state, the discharge state) of the battery cell, the temperature of the battery cell, the SOC, etc.

[0063] In step S201, the first charge-discharge rate of the battery cell is the charge-discharge rate of the battery cell in the use 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): (1) 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.

[0064] For example, an EIS detection circuit is deployed in the battery management system, which can detect the electrochemical impedance of the battery cell according to the detection requirements in the electrical equipment. The battery cell acquisition circuit in the battery management system can acquire the current, voltage, temperature and other parameters of the battery cell. By analyzing these parameters, the battery cell state data of the battery cell can be determined, and the first charge-discharge rate of the battery cell can be calculated. For example, according to the direction of the acquired charge-discharge current of the battery cell, it can be determined whether the battery cell is in a charging state or a discharging state; for example, by detecting the open circuit voltage of the battery cell, the SOC of the battery cell can be estimated; for example, according to the acquired charge-discharge current of the battery cell, the first charge-discharge rate of the battery cell can be calculated by combining formula (1).

[0065] In step S202, the second charge-discharge rate corresponding to the electrochemical impedance and the battery cell state data is obtained.

[0066] In step S202, the second charge-discharge rate can be determined by the pre-established association relationship between the battery cell impedance, the battery cell state and the charge-discharge rate. For example, Figure 3 The relationship curve between the charge transfer impedance and the charge-discharge rate of the battery cell in a certain battery cell state is shown. After obtaining the charge transfer impedance of the battery cell, the second charge-discharge rate can be obtained by Figure 3 The relationship curve shown in the figure.

[0067] It should be noted that the association relationship between the electrochemical impedance and the charge-discharge rate of the battery cell is different in different battery cell states. Therefore, in order to improve the accuracy of battery cell control, in the embodiments of the present application, the pre-established association relationship under different battery cell state data can be constructed, and in actual application, the association relationship matched with the battery cell state data is selected from the multiple pre-established association relationships to determine the second charge-discharge rate of the battery cell.

[0068] In step S203, the charge-discharge current of the battery cell is adjusted according to the relative rate between the first charge-discharge rate and the second charge-discharge rate, and the charge-discharge of the battery cell is controlled.

[0069] In step S203, the relative ratio between the first charge-discharge ratio and the second charge-discharge ratio can be a difference between the two charge-discharge ratios, can be a ratio, or can be a weighted value. The calculation manner of the relative ratio can be selected according to actual requirements, which is not limited here.

[0070] After the relative ratio between the two charge-discharge ratios is calculated, the battery management system can adjust the charge-discharge current of the battery cell based on the relative ratio. For example, when the relative ratio is small, the charge-discharge current of the battery cell can not be adjusted. When the relative ratio is large, the charge-discharge current of the battery cell can be adjusted in multiple steps.

[0071] It should be noted that the relative ratio between the first charge-discharge ratio and the second charge-discharge ratio is used to realize the charge-discharge control of the battery cell. The appropriate adjustment strategy is selected according to the size of the relative ratio, the risk of sharp change of the charge-discharge current of the battery cell is reduced, and the abnormality of the battery cell is avoided. The reliability and safety of the battery cell control are improved.

[0072] In the embodiments of the present application, the battery management system performs charge-discharge processing on the battery cell according to the adjusted charge-discharge current. The adjusted charge-discharge current is adjusted based on the charge-discharge ratio determined by the electrochemical impedance of the battery cell and the state data of the battery cell. This process takes into account the internal state of the battery cell. Therefore, the charge-discharge control of the battery cell based on the adjusted charge-discharge current can improve the charge-discharge control accuracy of the battery cell, and further improve the performance of the battery cell and prolong the service life of the battery cell.

[0073] Based on the schemes defined in steps S201 to S203, it can be known that the first charge-discharge ratio is a charge-discharge ratio determined based on the charge-discharge current and the capacity of the battery cell. The first charge-discharge ratio cannot reflect the internal state of the battery cell. Directly using the first charge-discharge ratio to control the charge-discharge of the battery cell has the problem of low charge-discharge control accuracy. The electrochemical impedance of the battery cell changes with the SOC, temperature, etc. of the battery cell. The electrochemical impedance can reflect the electrochemical reaction inside the battery cell. In the embodiments of the present application, the second charge-discharge ratio is determined based on the relationship between the electrochemical impedance and the charge-discharge ratio, rather than the internal resistance of the whole battery cell. The second charge-discharge ratio is consistent with the actual state of the battery cell. Therefore, by using the relative ratio between the first charge-discharge ratio and the second charge-discharge ratio to control the charge-discharge current of the battery cell, the battery cell can be more accurately controlled, and the charge-discharge control accuracy of the battery cell is improved.

[0074] As can be seen, the scheme provided in the embodiments of the present application can improve the charge-discharge control accuracy of the battery cell by using the charge-discharge ratio determined by the electrochemical impedance of the battery cell to control the charge-discharge of the battery cell.

[0075] The implementation process of the method provided in the embodiments of the present application will be introduced below.

[0076] In some embodiments, the battery management system can acquire electrochemical impedance through an EIS detection circuit. Specifically, the battery management system acquires cell status data and an impedance spectrum for each cell in the battery pack, and then acquires the electrochemical impedance corresponding to the cell status data of all cells from the impedance spectrum.

[0077] In the above embodiment, the impedance spectrum is used to characterize the correlation between the cell state data and the electrochemical impedance constructed in the use state, wherein the use state includes the static state, the charging state or the discharging state.

[0078] It should be noted that in the embodiment of the present application, the impedance spectrum is obtained by the electrical equipment by obtaining the electrochemical impedance of the battery cell and constructing a correlation between the battery cell status data and the electrochemical impedance. That is, the impedance spectrum in the embodiment of the present application is obtained by detection in the application scenario, rather than by experimental measurement in the laboratory.

[0079] Since the impedance spectrum in the embodiment of the present application is constructed in the electrical equipment, the impedance spectrum can be consistent with the actual usage status of the electrical equipment. Therefore, in the charge and discharge control of the battery cell, the impedance spectrum is used to determine the charge and discharge rate of the battery cell to adjust the charge and discharge current, and the charge and discharge control of the battery cell is performed based on the adjusted charge and discharge current, which can improve the control accuracy of the charge and discharge of the battery cell.

[0080] In one example, Figure 4 Shows a schematic diagram of the structure of the electrical equipment. Figure 4 It can be seen that in the embodiment of the present application, the electric device 300 may include a battery pack 200, the battery pack 200 includes a battery management system 100 and a battery cell 70, and the battery management system 100 is used to implement electrochemical impedance detection of the battery cell. 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 .

[0081] The excitation source 30 is connected to the battery cell 70 and is used to output an excitation current to the battery cell. The excitation source can be a signal generator that 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.

[0082] It should be noted that each cell has a corresponding excitation source, and one excitation source can excite one cell or multiple cells at the same time. In the embodiment of the present application, in order to improve the accuracy of electrochemical impedance spectroscopy, an excitation source is set for each cell.

[0083] The current acquisition chip 50 is connected with the battery cell 70, and is configured to acquire the charge-discharge current of the battery cell and the excitation current output by the excitation source. The current acquisition chip can be deployed in the data acquisition circuit 10 in the battery management system 1, and can be but is not limited to a current sensor. The battery cell is disposed in a circuit loop with a rectifier 40, and the rectifier can provide the battery cell with the charge-discharge current. Figure 1

[0084] When the battery cell is in a static state, the alternating current (i.e., the excitation current) output by the excitation source excites the battery cell alone; when the battery cell is in a charging state or a discharging state, the charge-discharge current of the battery cell and the excitation current of the excitation source jointly excite the battery cell, i.e., the charge-discharge current of the battery cell and the excitation current of the excitation source are superimposed, and the superimposed current is used to excite the battery cell, so that the processor obtains the voltage data and the current data of the battery cell under excitation, and then performs fast Fourier transform processing on the voltage data and the current data, and thus the impedance data of the battery cell can be obtained.

[0085] The battery cell state data of the battery cell in a preset range is adjusted, and the above process is repeated, so that multiple sets of battery cell state data and electrochemical impedance can be obtained, and a correlation between the multiple sets of battery cell state data and the electrochemical impedance can be constructed, and thus the impedance spectrum of the battery cell can be obtained.

[0086] It should be noted that the above-mentioned preset range is a range in which the battery cell can be normally used, for example, the SOC of the battery cell is 3%SOC-100%SOC, and the temperature of the battery cell is -20℃-45℃.

[0087] In addition, it should be further noted that, when the battery cell is in a charging state or a discharging state, the excitation source of the battery cell is derived from the excitation current output by the excitation source and the charge-discharge current of the battery cell. If the proportion between the excitation current and the charge-discharge current is set unreasonably, the battery cell can not be excited, and thus the accuracy of the electrochemical impedance detection of the battery cell is affected. Based on this, in the battery management system, a current adjustment circuit is also deployed. The current adjustment circuit can adjust the amplitude of the excitation current and / or the amplitude of the charge-discharge current, so that the superimposed current is within a reasonable range and can excite the battery cell.

[0088] At this point, the construction of the impedance spectrum of the battery cell is completed. After the construction of the impedance spectrum is completed, the battery management system can use the impedance spectrum and combine the battery cell state data of the battery cell to determine the electrochemical impedance of the battery cell, and then use the electrochemical impedance to determine the charge-discharge rate of the battery cell.

[0089] In some embodiments, Figure 5 A method for determining the first charge-discharge rate is shown, as shown in FIG. 5, the method comprises steps S501-S503: Figure 5 ​​Step S501, obtaining the electrochemical impedance of all cells in the battery pack; Step S502, determining outlier cells from all cells according to the electrochemical impedance of each cell in the battery pack; Step S503 : obtaining a first charge and discharge rate of the isolated battery cell according to the charge and discharge current of the isolated battery cell and the battery capacity of the isolated battery cell.

[0090] In the above embodiment, the outlier cell is a cell in the battery pack whose electrochemical impedance deviates from the electrochemical impedance of other cells by a degree greater than a preset threshold.

[0091] It should be noted that the battery cell contains a chemical system. If there are enough side reactions in the battery cell, the battery cell will become polarized, which will increase the charge transfer impedance of the battery cell. The greater the charge transfer impedance, the lower the power released by the battery cell and the smaller the current that can be output. If the charge and discharge current of the battery cell is too small, the battery management system will trigger an undervoltage warning and directly disconnect the battery cell from the electrical device, causing the electrical device to lose power and affect its operation. Therefore, it is necessary to detect the battery cell whose charge transfer impedance is greater than the preset charge transfer impedance threshold, i.e., the outlier battery cell, from the battery pack, and adjust the charge and discharge rate of the outlier battery cell to keep the charge and discharge of the outlier battery cell within a reasonable range, thereby reducing the risk of power outages in the electrical device.

[0092] In addition, a battery pack usually contains multiple battery cells, but not all battery cells require charge and discharge current adjustment. Therefore, before controlling the charge and discharge of the battery cells in the battery pack, the battery management system can first identify the outlier cells in the battery pack, and then control the charge and discharge of the outlier cells, which can improve the efficiency of the battery cell charge and discharge control.

[0093] Furthermore, after identifying the outlier cell in the battery pack, the battery management system collects the charge and discharge current and the nominal capacity of the outlier cell, and then uses formula (1) to calculate the first charge and discharge rate of the outlier cell.

[0094] In some embodiments, the outlier cell may be Figure 6 The method shown is used to determine the process, that is, step S502 includes the following steps S5021 to S5023: Step S5021, determining an impedance threshold according to the electrochemical impedance of all battery cells; Step S5022, determining the impedance deviation of each battery cell in the battery pack based on the relative value between the electrochemical impedance of each battery cell and the impedance threshold; Step S5023 , determining the cell whose impedance deviation is greater than a preset threshold from all the cells, and obtaining the outlier cell.

[0095] In the above embodiment, the impedance threshold can be any one of the median, mean, median, and mode of all cells in the battery pack. Alternatively, the impedance threshold can be weighted based on the cell's usage state. For example, in the charging state, the weighting coefficient is A1; in the discharging state, the weighting coefficient is A2; and in the static state, the weighting coefficient is A3.

[0096] In the above embodiment, the electrochemical impedance includes the charge transfer impedance. The relative value between the electrochemical impedance and the threshold value can be the difference or ratio between the charge transfer impedance and the impedance threshold value. 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 in the electrical equipment. Therefore, in the embodiment of the present application, the above-mentioned impedance deviation degree can be the degree to which the charge transfer impedance is higher than the impedance threshold value.

[0097] Exemplarily, the battery management system calculates the median charge transfer impedance of all cells in the battery pack as an impedance threshold. It then calculates the difference between the charge transfer impedance of each cell and the impedance threshold to determine the impedance deviation. Cells with impedance deviations greater than a preset threshold are considered outliers. Furthermore, when the battery management system detects the presence of an outlier cell in the battery pack, it begins executing the cell charge and discharge control method provided in the embodiments of the present application.

[0098] It can be seen from the above steps S5021 to S5023 that in the embodiment of the present application, the impedance threshold is determined by the electrochemical impedance of all battery cells, and is not a fixed value, so that the determination of the impedance threshold can be adapted to the working state of the battery cells in the battery pack, and then based on the impedance threshold, the outlier battery cells in the battery pack can be quickly and accurately located.

[0099] In some embodiments, Figure 7 The method for determining the second charge and discharge rate is shown as follows: Figure 7 As shown, the method includes steps S701 to S702: Step S701, obtaining a preset correlation relationship between cell impedance, cell state, and charge / discharge rate; Step S702 : determining a second charge / discharge rate corresponding to the electrochemical impedance and the cell state data from a preset association relationship.

[0100] It should be noted that the cell is an electrochemical system, and the cell's ohmic impedance is generally affected by the hardware environment, not by the chemical reactions within the cell. Therefore, in the present embodiment, the effect of the cell's ohmic impedance on the cell's charge and discharge rate is not considered. However, the charge transfer impedance can reflect the electrochemical reactions within the cell, so in the present embodiment, a correlation between the charge transfer impedance and the charge and discharge rate is established.

[0101] In steps S701-S702, the above-mentioned preset correlation can be obtained in a laboratory scenario, for example, in a laboratory, the charge and discharge current of the battery cell is changed under different SOC and temperature, thereby obtaining a plurality of groups of data, each group of data including the charge transfer impedance of the battery cell under the corresponding SOC and temperature and the charge and discharge rate corresponding to the charge and discharge current; then, the existing data fitting algorithm can be used to fit the plurality of groups of data to obtain the above-mentioned preset correlation; drawing the curve corresponding to the preset correlation, a curve graph as shown in FIG. 8 can be obtained, in which the charge and discharge rate is taken as the abscissa and the charge transfer impedance is taken as the ordinate. Figure 3

[0102] In addition, the above-mentioned preset correlation can also be detected in the electrical equipment, for example, in a vehicle scenario, the battery management system detects the electrochemical impedance of the battery cell in the vehicle, and collects the temperature, SOC, charge and discharge current and other data of the battery cell, and then performs data fitting on the collected data to obtain the above-mentioned preset correlation.

[0103] It should be noted that, from the above content, it can be known that the above-mentioned preset correlation is determined by the battery cell impedance, the state of the battery cell and the charge and discharge rate of the battery cell, therefore, the second charge and discharge rate obtained based on the preset correlation is more matched with the actual state of the battery cell, which lays a foundation for the accurate control of the subsequent battery cell charging and discharging.

[0104] In some embodiments, to realize the accurate control of the battery cell charging and discharging, the battery management system can also adjust the above-mentioned preset correlation. Specifically, as shown in FIG. 8, the adjustment of the preset correlation can include steps S801-S802: Figure 8 Step S801, obtaining the historical electrochemical impedance of the battery cell and the historical charge and discharge rate under the historical running state of the electrical equipment; Step S802, adjusting the preset correlation according to the historical electrochemical impedance and the historical charge and discharge rate to obtain the adjusted preset correlation.

[0105] In steps S801-S802, the historical battery cell impedance and the historical charge and discharge rate of the battery cell can be the battery cell impedance and the charge and discharge rate under the normal operation of the electrical equipment, for example, the historical battery cell impedance is the charge transfer impedance with an impedance value less than an impedance threshold, and the historical charge and discharge rate is the charge and discharge rate of the battery cell under a reasonable temperature and SOC.

[0106] ​​Further, in the above embodiment, the historical electrochemical impedance and the historical charge-discharge rate are determined based on the historical operation state of the electrical equipment, that is, the historical operation data of the electrical equipment is also considered in the process of adjusting the preset correlation, so that the adjusted preset correlation can be adapted to the electrical equipment, and then the charge-discharge of the battery cell is controlled based on the adjusted preset correlation, which can not only improve the control accuracy of the battery cell charge-discharge, but also optimize the performance of the battery cell in the electrical equipment and prolong the service life of the battery cell.

[0107] In some embodiments, the battery management system can adjust the correlation between the electrochemical impedance and the charge-discharge rate based on Figure 9 The preset correlation adjustment method shown in the figure is used to adjust the correlation between the electrochemical impedance and the charge-discharge rate, and specifically, the method includes the following steps S8021 to S8022: Step S8021, obtaining a fourth charge-discharge rate corresponding to the historical electrochemical impedance from the preset correlation; Step S8022, adjusting the preset correlation according to the relative value between the historical charge-discharge rate and the fourth charge-discharge rate to obtain the adjusted preset correlation.

[0108] 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, the historical operation state of the electrical equipment is further judged, if the electrical equipment is in a normal operation state, 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 an abnormal operation state, the preset correlation does not need to be adjusted.

[0109] In addition, when adjusting, the adjustment strategy can also be determined according to the size of the relative value between the historical charge-discharge rate and the fourth charge-discharge rate, for example, the above-mentioned relative value is large, the number of occurrences of the charge-discharge rate under the same battery cell state data and electrochemical impedance can be counted, that is, the first number of occurrences of the charge-discharge rate with a small difference from the historical charge-discharge rate and the second number of occurrences of the charge-discharge rate with a small difference from the fourth charge-discharge rate are counted, the first weight value corresponding to the historical charge-discharge rate and the second weight value corresponding to the fourth charge-discharge rate are determined according to the first number and the second number, and 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.

[0110] 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 consistent with the actual state of the electrical equipment, thereby laying a foundation for accurate control of the charge-discharge of the battery cell.

[0111] In some embodiments, after obtaining the first charge-discharge rate and the second charge-discharge rate of the outlier battery cell, the battery management system can control the charge-discharge of the battery cell according to the relative rate between the two. As shown in Figure 10 The method includes the following steps S1001 to S1003: Step S1001, in the case where the relative rate is greater than the first rate threshold, adjusting the charge-discharge rate of the outlier battery cell to obtain an adjusted charge-discharge rate; Step S1002, determining the adjusted charge-discharge current according to the adjusted charge-discharge rate and the cell capacity of the outlier battery cell; Step S1003, controlling the charge-discharge of the battery cell through the adjusted charge-discharge current.

[0112] In the above embodiments, the first rate threshold can be determined based on the historical use conditions of the battery cell in the electrical equipment. For example, if the vehicle is often in long-distance working conditions, the first rate threshold can be set to be larger.

[0113] 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, and at this time, the charge-discharge rate of the battery cell needs to be adjusted to reduce the difference between the adjusted charge-discharge rate and the second rate threshold, improve the control accuracy of the charge-discharge of the battery cell, and optimize the charge-discharge performance of the battery cell.

[0114] 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, and at this time, the charge-discharge performance of the battery cell is good, and there is no need to adjust the charge-discharge rate.

[0115] In the embodiments of the present application, when the relative rate is greater than the first rate threshold, it can be determined that the charge-discharge rate of the outlier battery cell needs to be adjusted. At this time, the battery management system can determine the adjustment strategy of the charge-discharge rate according to the difference between the first charge-discharge rate and the second charge-discharge rate.

[0116] In some embodiments, in the case where 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 battery cell is adjusted to the second charge-discharge rate, wherein the first rate threshold is less than the second rate threshold.

[0117] That is, in the embodiments of the present application, in the case that it is determined that the charge-discharge rate of the out-of-group battery cell needs to be adjusted, but the difference between the first charge-discharge rate and the second charge-discharge rate can be adjusted once to make the relative rate less than the first rate threshold, the first charge-discharge rate of the out-of-group battery cell can be directly adjusted to the second charge-discharge rate, and the second charge-discharge rate is used to control the charge-discharge of the out-of-group battery cell.

[0118] 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, and the control accuracy of the charge-discharge can be improved.

[0119] In some embodiments, in the case that the relative rate is greater than the second rate threshold, the adjustment method of the charge-discharge rate can be as shown in Figure 11 The method comprises the following steps: Step S1101, obtaining an adjustment coefficient corresponding to the relative rate; Step S1102, determining an adjustment amplitude according to the product of the adjustment coefficient and the relative rate; Step S1103, adjusting the first charge-discharge rate according to the adjustment amplitude to obtain a 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.

[0120] In the above embodiments, the adjustment coefficient, for example, an integer less than 1, can be positively correlated with the relative rate, that is, the larger the relative rate, the larger the adjustment coefficient. The correlation between the relative rate and the adjustment coefficient can be a linear relationship or a nonlinear relationship, which can be set according to actual use experience.

[0121] It should be noted that when the difference between the first charge-discharge rate and the second charge-discharge rate is large, if the first charge-discharge rate is directly adjusted to the second charge-discharge rate, the charge-discharge current of the battery cell will change greatly, reducing the performance of the battery cell; if the adjustment times are too many and the adjustment time is too long, the adjustment may not work, for example, due to the too long adjustment time, after the current battery cell is adjusted, other battery cells in the battery pack also need to be adjusted, and then other battery cells need to be adjusted again. In the embodiments of the present application, the adjustment amplitude is determined by the adjustment coefficient corresponding to the relative rate, and then the charge-discharge rate of the out-of-group battery cell is adjusted based on the adjustment amplitude, so that the charge-discharge current of the battery cell does not change suddenly in the adjustment process, the performance of the battery cell is improved, and at the same time, the adjustment time is not too long, and the effect of adjusting the charge-discharge current can be achieved.

[0122] In some embodiments, as shown in Figure 12 Step S1103 comprises the following steps S1201 to S1202: Step S1201: when the first charge-discharge rate is greater than the second charge-discharge rate, increase the first charge-discharge rate by an adjustment range to obtain a third charge-discharge rate; Step S1202 : When the first charge-discharge rate is less than the second charge-discharge rate, the first charge-discharge rate is reduced according to the adjustment range to obtain a third charge-discharge rate.

[0123] Through step S1201 to step S1202, the first charge and discharge rate is adjusted in a manner tending towards the second charge and discharge rate, so as to improve the control accuracy of the charge and discharge of the battery cell and optimize the charge and discharge performance of the battery cell.

[0124] This completes the explanation of the method provided in the embodiments of the present application.

[0125] It should be understood that, although the various steps in the flowcharts involved in the various embodiments described above are displayed in sequence according to the instructions of the arrows, these steps are not necessarily executed in sequence in the order indicated by the arrows. Unless otherwise specified herein, there is no strict order restriction on the execution of these steps, and these steps can be executed in other orders. Moreover, at least a portion of the steps in the flowcharts involved in the various embodiments described above can include multiple steps or multiple stages, and these steps or stages are not necessarily executed and completed at the same time, but can be executed at different times, and the execution order of these steps or stages is not necessarily to be carried out in sequence, but can be executed in turn or alternately with other steps or at least a portion of steps or stages in other steps.

[0126] Figure 13 A schematic structural diagram of an electronic device provided by an embodiment of the present application is shown.

[0127] like Figure 13 As shown, the electronic device is capable of implementing the exemplary hardware architecture of the electronic device according to the battery charge and discharge control method in the embodiment of the present application. The electronic device can refer to the electronic device in the embodiment of the present application.

[0128] The electronic device may include a processor 1301 and a memory 1302 storing computer program instructions.

[0129] Specifically, the processor 1301 may include a central processing unit (CPU), or an application specific integrated circuit (ASIC), or may be configured to implement one or more integrated circuits of the embodiments of the present application.

[0130] Memory 1302 may include a large-capacity memory for data or instructions. By way of example, and not limitation, memory 1302 may include a hard disk drive (HDD), a floppy disk drive, flash memory, an optical disk, a magneto-optical disk, magnetic tape, or a 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 certain embodiments, memory 1302 is non-volatile solid-state memory. In certain embodiments, memory 1302 may include read-only memory (ROM), random access memory (RAM), a magnetic disk storage medium device, an optical storage medium device, a flash memory device, or an electrical, optical, or other physical / tangible memory storage device. Therefore, typically, the 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 battery cell charge and discharge control method according to the present application.

[0131] The processor 1301 reads and executes computer program instructions stored in the memory 1302 to implement the battery cell charge and discharge control method in the above embodiment.

[0132] In one example, the electronic device may further include a communication interface 1303 and a bus 1304. Figure 13 As shown, the processor 1301 , the memory 1302 , and the communication interface 1303 are connected via a bus 1304 and communicate with each other.

[0133] The communication interface 1303 is mainly used to implement communication between various modules, devices, units and / or equipment in the embodiments of the present application.

[0134] Bus 1304 includes hardware, software, or both, to couple electronic devices to each other in a manner that allows information to be passed between or among the devices. By way of example and not limitation, a bus can include an Accelerated Graphics Port (AGP) or other graphics bus, an Enhanced Industry Standard Architecture (EISA) bus, a Front Side Bus (FSB), a HyperTransport (HT) interconnect, an Industry Standard Architecture (ISA) bus, an InfiniBand (IB) interconnect, a Low Pin Count (LPC) bus, a memory bus, a Micro Channel 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 another suitable bus or a combination of two or more of these. Where appropriate, bus 1304 can include one or more buses. Although the present application is described and illustrated with a particular bus, it is not limited to the bus or interconnects of the specific examples described and illustrated.

[0135] In one embodiment, the present application also provides a readable storage medium, having stored thereon computer program instructions, which when executed by a processor implement the above-mentioned method for controlling charging and discharging of battery cell.

[0136] In one embodiment, the present application also provides a computer program product, instructions in the computer program product being executed by a processor of an electronic device to cause the electronic device to perform the above-mentioned method for controlling charging and discharging of battery cell.

[0137] It is to be understood that the application is not limited to the particular configurations and processes described and illustrated herein. It is also to be understood that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting. Detailed descriptions of known methods are omitted so as not to obscure the application in unnecessary detail. In the above embodiments, a number of specific steps are described and illustrated as examples. However, the process of the application is not limited to the specific steps described and illustrated, and the order of the steps can be changed, or other steps can be added, or some steps can be omitted, without departing from the spirit of the application.

[0138] The functions shown in the above block diagrams 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, and the like. When implemented in software, the elements of the present application are program or code segments that are used to perform the required tasks. The program or code segments can be stored in a machine-readable medium, or transmitted through a data signal carried in a carrier wave over a transmission medium or communication link. A "machine-readable medium" includes any medium that can store or transport 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, and the like. The code segments can be downloaded via computer networks such as the Internet, intranets, and the like.

[0139] It is also important to note that the examples mentioned in the present application describe some methods or systems based on a series of steps or devices. However, the present application is not limited to the order of the above steps, that is, the steps can be performed in the order mentioned in the examples, or in an order different from the examples, or several steps can be performed simultaneously.

[0140] The above describes aspects of the present application with reference to flowcharts and / or block diagrams of the charge-discharge control method of the battery cell, the battery management system, the battery pack and the device according to embodiments of the present application. It should be understood that each block in the flowchart and / or block diagram, and the combination of blocks in the flowchart and / or block diagram, 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 produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing apparatus enable the implementation of the functions / acts specified in one or more blocks of the flowchart and / or block diagram. The processor can 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 can also be understood that each block in the block diagram and / or flowchart, and the combination of blocks in the block diagram and / or flowchart, can also be implemented by special hardware for performing specified functions or acts, or can be implemented by a combination of special hardware and computer instructions.

[0141] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than limit them. Although the present application has been described in detail with reference to the foregoing embodiments, it should be understood by those skilled in the art that the technical solutions recorded in the foregoing embodiments can be modified, or some or all of the technical features can be replaced equivalently. Such modifications or replacements do not change the essence of the corresponding technical solutions, which should be covered in the scope of the present application. In particular, the technical features mentioned in each embodiment can be combined in any manner as long as there is no structural conflict. The present 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 method for controlling charge and discharge of a battery cell, characterized in that: include: Obtaining electrochemical impedance of a battery cell in a battery pack, battery cell status data of the battery cell, and a first charge and discharge rate corresponding to a charge and discharge current of the battery cell; Acquire a second charge-discharge rate corresponding to the electrochemical impedance and the battery cell state data; The charge and discharge current of the battery cell is adjusted according to the relative ratio between the first charge and discharge ratio and the second charge and discharge ratio, so as to control the charge and discharge of the battery cell.

2. The method according to claim 1, characterized in that Obtaining a first charge and discharge rate corresponding to the charge and discharge current of the battery cell, comprising: Obtaining the electrochemical impedance of all cells in the battery pack; Determining an outlier cell from all the cells according to the electrochemical impedance of each cell in the battery pack, wherein the outlier cell is a cell whose electrochemical impedance deviates from the electrochemical impedance of other cells in the battery pack by a degree greater than a preset threshold; A first charge and discharge rate of the isolated battery cell is obtained according to the charge and discharge current of the isolated battery cell and the battery capacity of the isolated battery cell.

3. The method according to claim 2, characterized in that The step of determining an outlier cell from all the cells according to the electrochemical impedance of each cell in the battery pack includes: Determining an impedance threshold according to the electrochemical impedance of all the battery cells; determining the impedance deviation degree of each battery cell in the battery pack according to a relative value between the electrochemical impedance of each battery cell and the impedance threshold; The cell whose impedance deviation is greater than the preset threshold is determined from all the cells to obtain the outlier cell.

4. The method according to claim 2 or 3, characterized in that The step of adjusting the charge and discharge current of the battery cell according to the relative ratio between the first charge and discharge rate and the second charge and discharge rate to control the charge and discharge of the battery cell includes: When the relative rate is greater than a first rate threshold, adjusting the charge and discharge rate of the outlier cell to obtain an adjusted charge and discharge rate; Determining the adjusted charge and discharge current according to the adjusted charge and discharge rate and the cell capacity of the outlier cell; The charge and discharge of the battery cell is controlled by the adjusted charge and discharge current.

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

6. The method according to claim 5, characterized in that The method further comprises: When the relative magnification is greater than the second magnification threshold, obtaining an adjustment coefficient corresponding to the relative magnification, wherein the adjustment coefficient is positively correlated with the relative magnification; Determining an adjustment range according to the product of the adjustment coefficient and the relative magnification; The first charge and discharge rate is adjusted according to the adjustment range to obtain a third charge and discharge rate, wherein a relative value between the third charge and discharge rate and the second charge and discharge rate is less than the first rate threshold.

7. The method according to claim 6, characterized in that The adjusting the first charge-discharge rate according to the adjustment range to obtain a third charge-discharge rate includes: When the first charge-discharge rate is greater than the second charge-discharge rate, increasing the first charge-discharge rate according to the adjustment range to obtain the third charge-discharge rate; and / or When the first charge-discharge rate is less than the second charge-discharge rate, the first charge-discharge rate is reduced according to the adjustment range to obtain the third charge-discharge rate.

8. The method according to claim 1, characterized in that The obtaining of the electrochemical impedance of the battery cells in the battery pack includes: Obtaining cell state data and an impedance spectrum of each cell in the battery pack, wherein the impedance spectrum is used to characterize the correlation between the cell state data and the electrochemical impedance constructed in a usage state, wherein the usage state includes a static state, a charging state, or a discharging state; The electrochemical impedance corresponding to the cell state data of all the cell is obtained from the impedance spectrum.

9. The method according to claim 1, characterized in that The obtaining of a second charge-discharge rate corresponding to the electrochemical impedance and the cell state data includes: Obtain the preset correlation between cell impedance, cell status, and charge and discharge rate; A second charge and discharge rate corresponding to the electrochemical impedance and the cell state data is determined based on the preset association relationship.

10. The method according to claim 9, characterized in that The method further comprises: Obtaining historical electrochemical impedance and historical charge and discharge rates of the battery cell under historical operating conditions of the electrical equipment; The preset association relationship is adjusted according to the historical electrochemical impedance and the historical charge and discharge rate to obtain an adjusted preset association relationship.

11. The method according to claim 10, characterized in that The adjusting the preset association relationship according to the historical electrochemical impedance and the historical charge and discharge rate to obtain the adjusted preset association relationship includes: Obtaining a fourth charge-discharge rate corresponding to the historical electrochemical impedance from the preset association relationship; The preset association relationship is adjusted according to a relative value between the historical charge and discharge rate and the fourth charge and discharge rate to obtain the adjusted preset association relationship.

12. A battery management system, characterized in that: include: a data acquisition circuit, configured to obtain electrochemical impedance of a battery cell in a battery pack, cell status data of the battery cell, a first charge and discharge rate corresponding to a charge and discharge current of the battery cell, and a second charge and discharge rate corresponding to the electrochemical impedance and the cell status data; A processor is connected to the data acquisition circuit and is used to adjust the charge and discharge current of the battery cell according to the relative ratio between the first charge and discharge rate and the second charge and discharge rate, so as to control the charge and discharge of the battery cell.

13. A battery pack, characterized in that: The invention comprises a battery cell and the battery management system according to claim 12.

14. An electrical device, characterized in that: Including the battery pack according to claim 13.

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