A battery impedance online identification method, device, electronic device and medium

Abstract

The embodiments of the present invention provide a method, device, electronic device and medium for online identification of battery impedance, which have the following beneficial effects: after the battery meets the static state, the state of charge after static is calculated; when entering the constant current state, the state of charge after static, the constant current, the constant current voltage and the polarization mark are recorded according to the sampling time interval; when the battery enters the static state again, the reference state of charge recorded in the constant current state is corrected according to the latest state of charge after static; the corrected reference state of charge corresponds to the reference open circuit voltage, and the equivalent impedance is obtained from the reference open circuit voltage, and the corrected impedance is calculated from the equivalent impedance; the polarization mark corresponding to the reference state of charge is used to update the calibrated impedance with the corrected impedance. The present invention is aimed at identifying the battery impedance online in real time when the battery operating condition meets specific conditions, without the need for regular offline maintenance of the battery, and effectively improves the efficiency of battery impedance update, and can be obtained in real time when the battery is in normal working state, with high real-time performance.

Description

Technical Field

[0001] The present invention relates to the technical field of battery management, and in particular to a method, device, electronic equipment and medium for online identification of battery impedance. Background Art

[0002] Currently, batteries are widely used in all walks of life. For a new battery, battery management system developers can perform various calibrations on the battery to complete its control and SOX (English: State of X, Chinese: a collection of battery states, including SOC, SOH, SOP, etc.) algorithm requirements. However, as the battery ages, the battery parameters calibrated in the laboratory will no longer be applicable, resulting in errors in SOX estimation and affecting user experience.

[0003] The current calibration of battery models has different parameter structures due to different models, but the industry consensus is that the composition of the terminal voltage of the battery in terms of charging and discharging performance can be divided into open circuit voltage, ohmic impedance, electrochemical impedance and concentration impedance. The open circuit voltage is an inherent property of the battery. It changes little after aging and is generally treated as constant. The ohmic impedance comes from the resistance characteristics of the diaphragm, positive and negative electrode materials, and tabs. The electrochemical impedance comes from the resistance characteristics that hinder the operation of electrons. Ohmic impedance and electrochemical impedance occur quickly, and their impedance parameters can be obtained by obtaining voltage changes through current changes. For concentration polarization impedance, a longer constant current state is required to obtain it.

[0004] In order to cope with the impact of battery aging, it is necessary to update the calibration parameters of the battery, especially the battery impedance. Usually, recalibration is completed by running specific calibration conditions regularly. However, this regular maintenance method requires running specific conditions, which affects the normal operation of the battery, consumes electricity, and cannot achieve real-time tracking.

[0005] Therefore, how to improve the updating efficiency and real-time performance of battery impedance is a technical problem that needs to be solved urgently by those skilled in the art. Summary of the invention

[0006] In order to overcome the shortcomings of low efficiency and poor real-time performance of the existing battery impedance update method, the present invention proposes a battery impedance online identification method, device, electronic device and medium.

[0007] In order to achieve the above object, according to a first aspect of the present invention, an embodiment of the present invention provides a method for online identification of battery impedance, the method comprising the following steps:

[0008] When the battery meets the static state, the open circuit voltage is collected and the state of charge after static state is calculated. The state of charge after static state is the difference between the state of charge corresponding to the current open circuit voltage and the time integral of the collected current relative to the ratio of the rated capacity of the battery;

[0009] When the battery meets the constant current state, the state of charge after standing, the constant current, the constant current voltage and the polarization mark are recorded according to the sampling time interval; wherein the sampling time interval is the time interval calculated by the sampling accuracy, the open circuit voltage accuracy, the state of charge accuracy, the collection current and the rated capacity of the battery; the polarization mark represents the numerical relationship between the voltage change rate and the open circuit voltage change rate;

[0010] When the battery meets the static state again, the reference state of charge obtained by recording data in the constant current state is corrected according to the latest calculated state of charge after static state, wherein the reference state of charge is the last value of the state of charge after static state recorded in the constant current state, or the value after sliding window filtering or average filtering of all the state of charge after static state recorded in the constant current state;

[0011] The corrected reference state of charge corresponds to a reference open circuit voltage, an equivalent impedance is obtained from the reference open circuit voltage, and a corrected impedance is calculated based on the equivalent impedance, wherein the corrected impedance is the product of a difference between the calibrated impedance and the equivalent impedance and a confidence level;

[0012] According to the polarization sign corresponding to the reference state of charge, the corresponding calibration impedance is updated using the corrected impedance.

[0013] Optionally, the calculation formula of the sampling time interval is as follows:

[0014] ,

[0015] in, represents the sampling time interval, Indicates the sampling accuracy, Indicates the rated capacity of the battery. Indicates the acquisition current, .

[0016] Optionally, the calculation formula for recording the state of charge after standing still is as follows:

[0017] ,

[0018] in, Indicates the recorded state of charge after resting. It indicates the state of charge corresponding to the current open circuit voltage, t indicates a time period, I indicates the collected current, Indicates the rated capacity of the battery.

[0019] Optionally, the corrected reference state of charge calculation formula is as follows:

[0020] ,

[0021] in, represents the corrected reference state of charge, It is the state of charge corresponding to the open circuit voltage when recording the reference state of charge. is the reference state of charge, It is the state of charge corresponding to the most recently recorded open circuit voltage when entering the static state again. It is the latest recorded state of charge after the vehicle enters the static state again.

[0022] Optionally, the corrected reference state of charge corresponds to a reference open circuit voltage, and the equivalent impedance is obtained from the reference open circuit voltage, and the calculation formula is as follows:

[0023] ,

[0024] in, represents the equivalent impedance, represents the open circuit voltage corresponding to the corrected reference state of charge, Indicates the constant current voltage corresponding to the corrected reference state of charge, Indicates the constant current corresponding to the corrected reference state of charge.

[0025] Optionally, the modified impedance is calculated according to the equivalent impedance, and the formula is as follows:

[0026] Ris_Step=|Ris_Now-Ristn_true |*η

[0027] Among them, Ris_Step represents the corrected impedance, Ris_Now represents the calibrated impedance, Risn_true represents the equivalent impedance, and η represents the confidence level, which is between 0 and 1.

[0028] Optionally, the updating of the corresponding calibrated impedance using the corrected impedance according to the polarization mark corresponding to the reference state of charge includes:

[0029] When the polarization flag indicates that the voltage change rate is greater than the open circuit voltage change rate, and Ris_Now is less than Risn_true, the updated calibration impedance Ris_New=Ris_Now+Ris_Step;

[0030] When the polarization mark indicates that the voltage change rate is less than the open circuit voltage change rate, and Ris_Now is greater than Risn_true, the updated calibration impedance Ris_New=Ris_Now-Ris_Step;

[0031] When the polarization mark indicates that the voltage change rate is equal to or approximately equal to the open circuit voltage change rate, if Ris_Now is less than Risn_true, the updated calibration impedance Ris_New=Ris_Now+Ris_Step; if Ris_Now is greater than Risn_true, the updated calibration impedance Ris_New=Ris_Now-Ris_Step;

[0032] Wherein, Ris_New represents the updated calibrated impedance.

[0033] According to a second aspect of the present invention, an embodiment of the present invention further provides a battery impedance online identification device, comprising:

[0034] A post-stationary state-of-charge recording module is used to collect the open circuit voltage and calculate the post-stationary state-of-charge when the battery meets the stationary state. The post-stationary state-of-charge is the difference between the state-of-charge corresponding to the current open circuit voltage and the time integral of the collected current relative to the ratio of the rated capacity of the battery;

[0035] A sampling module, used for recording the state of charge after standing, constant current, constant current voltage and polarization mark according to the sampling time interval when the battery meets the constant current state; wherein the sampling time interval is the time interval calculated by the sampling accuracy, open circuit voltage accuracy, state of charge accuracy, collection current and battery rated capacity; the polarization mark represents the numerical relationship between the voltage change rate and the open circuit voltage change rate;

[0036] A state of charge correction module is used to correct the reference state of charge obtained by recording data in the constant current state according to the latest calculated state of charge after the static state when the battery meets the static state again, wherein the reference state of charge is the last value of the state of charge after the static state recorded in the constant current state, or the value of all the state of charge after the static state recorded in the constant current state after sliding window filtering or average filtering;

[0037] A corrected impedance calculation module, used for the corrected reference state of charge corresponding to the reference open circuit voltage, obtaining the equivalent impedance from the reference open circuit voltage, and calculating the corrected impedance according to the equivalent impedance, wherein the corrected impedance is the product of the difference between the calibrated impedance and the equivalent impedance and the confidence level;

[0038] The updating module is used to update the corresponding calibrated impedance using the corrected impedance according to the polarization mark corresponding to the reference charge state.

[0039] According to the third aspect of the present invention, an embodiment of the present invention further provides an electronic device, comprising a memory and a processor, wherein the memory stores a computer program, and when the processor executes the computer program, the steps of the battery impedance online identification method in any of the above embodiments are implemented.

[0040] According to the fourth aspect of the present invention, an embodiment of the present invention further provides a storage medium, wherein the storage medium stores at least one instruction, at least one program, a code set or an instruction set, and the at least one instruction, the at least one program, the code set or the instruction set is loaded and executed by a processor to implement the steps of the battery impedance online identification method in any of the above embodiments.

[0041] As described above, an embodiment of the present invention provides a battery impedance online identification method, device, electronic device and medium, which have the following beneficial effects: when the battery meets the static state, the open circuit voltage is collected, and the state of charge after static is calculated, the state of charge after static is the state of charge corresponding to the current open circuit voltage, and the difference between the time integral of the collected current and the ratio of the rated capacity of the battery; when the battery meets the constant current state, the state of charge after static, the constant current, the constant current voltage and the polarization mark are recorded according to the sampling time interval; wherein the sampling time interval is the time interval calculated by the sampling accuracy, the open circuit voltage accuracy, the state of charge accuracy, the collected current and the rated capacity of the battery; the polarization mark represents the voltage change rate and the open circuit voltage accuracy. The numerical relationship of the rate of change of the circuit voltage; when the battery meets the static state again, the reference state of charge obtained by recording the data in the constant current state is corrected according to the latest calculated state of charge after static state, the reference state of charge is the last value of the state of charge after static state recorded in the constant current state, or the value after sliding window filtering or average filtering of all the state of charge after static state recorded in the constant current state; the corrected reference state of charge corresponds to the reference open circuit voltage, the equivalent impedance is obtained from the reference open circuit voltage, and the corrected impedance is calculated according to the equivalent impedance, the corrected impedance is the product of the difference between the calibrated impedance and the equivalent impedance and the confidence level; according to the polarization mark corresponding to the reference state of charge, the corrected impedance is used to update the corresponding calibrated impedance. After the battery is aged, the present invention identifies the battery impedance online in real time when the battery operating condition meets specific conditions, without the need for regular offline maintenance of the battery, effectively improves the efficiency of battery impedance update, and can be obtained in real time under the normal working state of the battery, with high real-time performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] Figure 1 It is a flow chart of a battery impedance online identification method provided by an embodiment of the present invention;

[0043] Figure 2 This is a schematic diagram of the relationship between current and voltage during a calibration process provided by an embodiment of the present invention;

[0044] Figure 3 It is a structural schematic diagram of a battery impedance online identification device provided by an embodiment of the present invention;

[0045] Figure 4It is a schematic diagram of the hardware structure of an electronic device for executing a battery impedance online identification method provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0046] In order to enable those skilled in the art to better understand the technical solutions in the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0047] See also Figures 1 to 4 It should be noted that the illustrations provided in this embodiment are only used to illustrate the basic concept of the present invention in a schematic manner, and the illustrations only show components related to the present invention rather than being drawn according to the number, shape and size of components in actual implementation. In actual implementation, the type, quantity and proportion of each component may be changed arbitrarily, and the component layout may also be more complicated.

[0048] See also Figure 1 , is a flow chart of a battery impedance online identification method provided by an embodiment of the present invention, such as Figure 1 As shown, the embodiment of the present invention shows the process of the battery impedance online identification method.

[0049] Step S101: When the battery meets the static state, the open circuit voltage is collected and the state of charge after the static state is calculated. The state of charge after the static state is the difference between the state of charge corresponding to the current open circuit voltage and the time integral of the collected current relative to the rated capacity of the battery.

[0050] In an embodiment of the present invention, the equivalent impedance and open circuit voltage corresponding to the battery SOC (English: State Of Charge, Chinese: state of charge) are first calibrated in an offline state. In the specific implementation, the calibration method is not limited, for example, it can be obtained through EIS (English: Electrochemical Impedance Spectroscopy, Chinese: electrochemical impedance spectroscopy), or through a voltage drop generated by a long-term constant current state.

[0051] In an exemplary embodiment, the calibration method may be combined with Figure 2 ,like Figure 2As shown, it is a schematic diagram of the current-voltage relationship in a calibration process provided by an embodiment of the present invention. The calibration process includes: fully charging the battery, discharging it with a current of 1A, and using the discharge capacity as a stop sign. For example, discharging 10% of the capacity, recording the cut-off voltage of 4.285V at this time, and letting it stand for 2 hours. At this time, the OCV (Open Circuit Voltage) of SOC=90% is 4.344V. The equivalent resistance R of this point is calculated to be (4.344-4.285) / 1=0.059Ω. The OCV and equivalent impedance of other SOC points are obtained in this way. The calibration data are shown in the following table:

[0052]

[0053] Subsequent embodiments will utilize the calibration data represented by the above table to identify equivalent impedance.

[0054] For the battery to be calibrated, let the battery stand still. When the battery is in the standing state, start the estimation, collect the open circuit voltage, and query the above table through the open circuit voltage to obtain the state of charge corresponding to the current open circuit voltage. Further calculate the state of charge after standing still through the following formula:

[0055] ,

[0056] in, Indicates the recorded state of charge after resting. It indicates the state of charge corresponding to the current open circuit voltage, t indicates a time period, I indicates the collected current, Indicates the rated capacity of the battery.

[0057] It should be noted that the state of charge recorded here after standing still It may correspond to a discharge state or a charge state, which is not limited in the embodiment of the present invention.

[0058] For example, the battery rest condition is met, and the battery is kept at rest until it works. The current open circuit voltage OCV=4.344V is measured, and the calibration data is queried to obtain the corresponding SOC=90%, that is, is 90%, t is a time period, representing the time from meeting the static condition to the current moment, I is the collected current = 1A, The battery rated capacity = 4.9*3600As. The charge state after standing still is calculated by the above formula to be 0.899.

[0059] Step S102: When the battery meets the constant current state, the state of charge, constant current, constant current voltage and polarization mark after standing are recorded according to the sampling time interval; wherein the sampling time interval is a time interval calculated by the sampling accuracy, open circuit voltage accuracy, state of charge accuracy, collection current and battery rated capacity; the polarization mark represents the numerical relationship between the voltage change rate and the open circuit voltage change rate.

[0060] When the battery meets the constant current condition, further data is recorded. The constant current condition can be when the current passing through the battery is less than a threshold value and lasts for a certain period of time as a criterion, which is not specifically limited in the embodiment of the present application. For ease of explanation, the constant current condition of the present application is exemplarily set to a current of 1A and a duration of 5s. When the constant current condition is met, the battery records a set of data, including the state of charge after standing, constant current, constant current voltage and polarization mark. This set of data represents the battery information of a period of time of the battery under the constant current condition, and according to the specific implementation, this set of data can include data of any multiple points, which are described in detail as follows:

[0061] The state of charge after standing is the state of charge obtained by continuous collection and calculation according to the above steps, which will not be repeated here. Further, the constant current and constant current voltage of the test are measured, for example, the constant current I is measured to be 1A, and the constant current voltage V is 4.299V.

[0062] Determine the polarization mark, which characterizes the numerical relationship between the voltage change rate dV and the open circuit voltage change rate dOCV corresponding to the current recording point. Specifically, if |dV|>|dOCV|, it is considered that it is not fully polarized, and the real impedance is greater than the current impedance performance, marked as Flag_M; if |dV|<|dOCV|, it is considered to be over-polarized, and the real impedance is less than the current impedance performance, marked as Flag_L; if |dV|≈|dOCV|, it is considered to be fully polarized, and the real impedance is equal to the current impedance performance, marked as Flag_O. Both dV and dOCV are measured. In the actual test process, the influence of noise can be further considered, and the voltage and current can be filtered to determine the filtered voltage change rate and open circuit voltage change rate for a period of time. Based on the above description of determining the polarization mark, a polarization mark can also be obtained, that is, any one of Flag_M, Flag_L and Flag_O, for example, the polarization mark obtained is Flag_M.

[0063] This will result in a record point [0.899, 1, 4.299, Flag_M].

[0064] The sampling time interval is calculated as follows:

[0065] ,

[0066] in, represents the sampling time interval, Indicates the sampling accuracy, Indicates the rated capacity of the battery. Indicates the acquisition current, , that is, the slope of SOC-OCV, which can also be calculated through the table in step S101.

[0067] In an exemplary embodiment, It is the minimum accuracy with which the current measurement system can measure the open circuit voltage OCV, for example =0.001V; is the rated capacity of the battery described in the above embodiment, i.e. 4.9*3600As; I is the collection current, i.e. 1A; is 0.1, In this case it is 0.117V, then =0.1 / 0.117. In this way, the calculated sampling time interval is =(0.001*4.9*3600) / (1*0.117)=15.076s, which is approximately equal to 15s.

[0068] According to the sampling time interval, any number of recording points can be collected to form a recording sequence until the constant current condition is not met, thereby obtaining the data of the constant current condition. The recording sequence can be represented as [SOCtn, In, Vn, Flag_N], n=1,2,3…n, N={M,L,O}.

[0069] In an exemplary embodiment, the record sequence is: [0.899, 1, 4.299, Flag_M], [0.899, 1, 4.292 Flag_M] ... [0.790, 1, 4.169, Flag_O].

[0070] Step S103: When the battery meets the static state again, the reference state of charge obtained from the data recorded in the constant current state is corrected according to the latest calculated state of charge after static state.

[0071] The reference state of charge is the last value of the state of charge after standing still recorded in the constant current state, or the value of all the state of charge after standing still in the constant current state after sliding window filtering or average filtering. In the specific implementation, when the sampling time is long enough, the recording sequence will converge to the complete polarization state. When the polarization mark is Flag_M or Flag_L, the calculated impedance can be used as a boundary reference, and its correction amplitude is reduced, so if it is marked as Flag_O for a long time, it can be considered that the calculated equivalent impedance has high credibility. In the specific implementation, a recording point can be selected according to the specific test scenario. For example, only the last value needs to be recorded and calculated. Of course, multiple values ​​can also be recorded for sliding window filtering or average filtering. For the convenience of explanation, this embodiment selects the data of the last recording point to describe the subsequent processing steps, that is, [0.790,1,4.169, Flag_O], so that the reference state of charge is 0.790.

[0072] According to the description of step S101, after recording the data satisfying the constant current state, the battery enters the static state again and then continues to correct the reference state of charge according to the latest recorded data. The formula is as follows:

[0073] ,

[0074] in, represents the corrected reference state of charge, It is the state of charge corresponding to the open circuit voltage when the reference charge is recorded. is the reference state of charge, It is the state of charge corresponding to the most recently recorded open circuit voltage when entering the static state again. The most recently recorded post-rest state of charge when the vehicle enters rest state again.

[0075] Specifically, The value is an open circuit voltage obtained when measuring the last recording point of the first constant current state, and the state of charge value is obtained by querying the calibration data of the above embodiment; is the reference state of charge, i.e., the state of charge value after standing still at the last recording point determined in the above embodiment, taking 0.790 as an example; The state of charge is obtained by the latest open circuit voltage recorded when entering the static state again, and by querying the calibration data. If the open circuit voltage OCV recorded at this time is 4.226V, the state of charge is 80% after checking the table. =0.8; is the state of charge after rest at the first recorded point after re-entering the rest state, calculated by the formula of the above embodiment. For example, after the calculation of the above process, the corrected reference state of charge is obtained. =0.800, then the record point can be updated to [0.800,1,4.169, Flag_O], and the equivalent impedance calculation can be further performed based on this data.

[0076] Step S104: The corrected reference state of charge corresponds to a reference open circuit voltage, an equivalent impedance is obtained from the reference open circuit voltage, and a corrected impedance is calculated based on the equivalent impedance, wherein the corrected impedance is the product of the difference between the calibrated impedance and the equivalent impedance and the confidence level.

[0077] After obtaining the corrected reference state of charge according to the above steps, the equivalent impedance is first calculated using the following formula:

[0078] ,

[0079] in, represents the equivalent impedance, represents the open circuit voltage corresponding to the corrected reference state of charge, Indicates the constant current voltage corresponding to the corrected reference state of charge, Indicates the constant current corresponding to the corrected reference state of charge.

[0080] Specifically, the calibration data is also queried, and the corrected reference state of charge corresponds to an open circuit voltage. For example, if the corrected reference state of charge is 0.800, the open circuit voltage obtained after looking up the table is 4.226V, that is, =4.226V. Further, other data of the recording point corresponding to the corrected reference state of charge include constant current power supply and constant current voltage. In this embodiment, the constant current voltage =4.169V, constant current power supply =1A. Substituting the above data into the formula, the equivalent impedance can be calculated. =0.057Ω.

[0081] The corrected impedance is calculated based on the equivalent impedance, and the formula is as follows:

[0082] Ris_Step=|Ris_Now-Ristn_true |*η,

[0083] Among them, Ris_Step represents the corrected impedance, Ris_Now represents the calibrated impedance, Risn_true represents the equivalent impedance, and η represents the confidence level, which is between 0 and 1.

[0084] Specifically, the current calibration impedance is the impedance obtained by looking up the table of the corrected reference state of charge. The corrected reference state of charge in the above embodiment is 0.800. The calibration data is queried to obtain the corresponding impedance of 0.040Ω, that is, Ris_Now=0.004Ω. η is the confidence level, which can be dynamically set according to the constant current duration and the type of triggered polarization mark. For example, if the constant current duration is long, the confidence level can be further increased. If the polarization mark is Flag_O, the confidence level can be further increased. If the polarization mark is Flag_M or Flag_L, the confidence level is correspondingly reduced. The specific value of the confidence level is not limited in the embodiment of the present invention. Taking η=1 as an example, substituting the data calculated in the previous step, the corrected impedance Ris_Step=|0.040-0.057|*1=0.017Ω can be calculated.

[0085] Step S105: updating the calibrated impedance using the corrected impedance according to the polarization mark corresponding to the reference state of charge.

[0086] Specifically, when the polarization flag indicates that the voltage change rate is greater than the open circuit voltage change rate, and Ris_Now is less than Risn_true, Ris_New=Ris_Now+Ris_Step;

[0087] When the polarization flag indicates that the voltage change rate is less than the open circuit voltage change rate, and Ris_Now is greater than Risn_true, Ris_New = Ris_Now-Ris_Step;

[0088] When the polarization mark indicates that the voltage change rate is equal to or approximately equal to the open circuit voltage change rate, if Ris_Now is less than Risn_true, Ris_New=Ris_Now+Ris_Step; if Ris_Now is greater than Risn_true, Ris_New=Ris_Now-Ris_Step; wherein Ris_New represents the updated calibrated impedance, wherein approximately equal includes approximately assuming that the voltage change rates of the two are equal.

[0089] In an exemplary embodiment, data is obtained according to the above embodiment. In step S102, the recording point corresponding to the corrected reference state of charge is [0.800, 1, 4.169, Flag_O]. The corrected impedance Ris_Step obtained in step S103 is 0.017Ω. At this time, by querying the calibration data, the calibration impedance Ris_Now corresponding to the reference state of charge of 0.800 is 0.040Ω. The polarization flag is Flag_O, which corresponds to the case where the voltage change rate is equal to or approximately equal to the open circuit voltage change rate, and Ris_Now (0.040Ω) is less than (0.057Ω), then the updated calibrated impedance Ris_New=0.040+0.017=0.057Ω.

[0090] In this way, during the normal working state of the battery, each time the static condition is met, then the constant current condition is met, and then the constant current condition is met again, data can be continuously collected to update the calibration data measured in the offline state, thereby realizing online detection of the battery impedance. There is no need to take the battery offline for maintenance and recalibrate it, and no additional energy consumption is required. It not only improves the recognition efficiency of the battery impedance, but also has high real-time performance. At the same time, it avoids the consumption of additional energy and has the effect of saving testing costs.

[0091] It can be seen from the description of the above embodiments that an embodiment of the present invention provides a method for online identification of battery impedance, including collecting open circuit voltage and calculating the state of charge after the battery meets the static state, wherein the state of charge after the static state is the state of charge corresponding to the current open circuit voltage and the difference between the time integral of the collected current and the ratio of the rated capacity of the battery; when the battery meets the constant current state, the state of charge after the static state, the constant current, the constant current voltage and the polarization mark are recorded according to the sampling time interval; wherein the sampling time interval is the time interval calculated by the sampling accuracy, the open circuit voltage accuracy, the state of charge accuracy, the collected current and the rated capacity of the battery; the polarization mark represents the voltage change rate and the open circuit voltage change rate ; when the battery meets the static state again, the reference state of charge obtained by recording data in the constant current state is corrected according to the latest calculated state of charge after static state, the reference state of charge is the last value of the state of charge after static state recorded in the constant current state, or the value of all the state of charge after static state recorded in the constant current state after sliding window filtering or average filtering; the corrected reference state of charge corresponds to the reference open circuit voltage, the equivalent impedance is obtained from the reference open circuit voltage, and the corrected impedance is calculated according to the equivalent impedance, the corrected impedance is the product of the difference between the calibrated impedance and the equivalent impedance and the confidence; according to the polarization mark corresponding to the reference state of charge, the corrected impedance is used to update the corresponding calibrated impedance. After the battery is aged, the present invention identifies the battery impedance online in real time when the battery operating condition meets specific conditions, without the need for regular offline maintenance of the battery, effectively improves the battery impedance update efficiency, and can be obtained in real time under the normal working state of the battery, with high real-time performance, and at the same time, no energy consumption is required, and the test cost is effectively reduced.

[0092] Through the description of the above method embodiments, the technicians in the relevant field can clearly understand that the present invention can be implemented by means of software plus the necessary general hardware platform, and of course it can also be implemented by hardware, but in many cases the former is a better implementation method. Based on this understanding, the technical solution of the present invention is essentially or the part that contributes to the prior art can be embodied in the form of a software product, which is stored in a storage medium and includes a number of instructions for a computer device (which can be a personal computer, a server, or a network device, etc.) to perform all or part of the steps of the method described in each embodiment of the present invention. The aforementioned storage medium includes: various media that can store program codes, such as read-only memory (ROM), random access memory (RAM), magnetic disk or optical disk.

[0093] An embodiment of the present invention provides a non-volatile computer storage medium, wherein the computer storage medium stores computer executable instructions, and the computer executable instructions can execute the battery impedance online identification method in any of the above method embodiments.

[0094] Corresponding to the embodiment of the battery impedance online identification method provided by the present invention, the present invention also provides a battery impedance online identification device.

[0095] See also Figure 3 , is a schematic diagram of the structure of a battery impedance online identification device provided by an embodiment of the present invention. As shown in the figure, the device includes:

[0096] The post-stationary state-of-charge recording module 11 is used to collect the open circuit voltage and calculate the post-stationary state-of-charge when the battery meets the stationary state. The post-stationary state-of-charge is the difference between the state-of-charge corresponding to the current open circuit voltage and the time integral of the collected current relative to the ratio of the rated capacity of the battery;

[0097] The sampling module 12 is used to record the state of charge, constant current, constant current voltage and polarization mark after standing still according to the sampling time interval when the battery meets the constant current condition; wherein the sampling time interval is a time interval calculated by the sampling accuracy, the open circuit voltage accuracy, the state of charge accuracy, the collection current and the rated capacity of the battery; the polarization mark represents the numerical relationship between the voltage change rate and the open circuit voltage change rate;

[0098] The state of charge correction module 13 is used to correct the reference state of charge obtained by recording data in the constant current state according to the latest recorded state of charge after the static state when the battery meets the static condition again, wherein the reference state of charge is the last value of the state of charge after the static state recorded in the constant current condition, or the value of all the state of charge after the static state recorded in the constant current condition after sliding window filtering or average filtering;

[0099] A modified impedance calculation module 14 is used to correspond the modified reference state of charge to the reference open circuit voltage, obtain the equivalent impedance from the reference open circuit voltage, and calculate the modified impedance according to the equivalent impedance, wherein the modified impedance is the product of the difference between the calibrated impedance and the equivalent impedance and the confidence level;

[0100] The updating module 15 is used to update the corresponding calibrated impedance using the corrected impedance according to the polarization mark corresponding to the reference state of charge.

[0101] In an exemplary embodiment, the sampling time interval calculation formula executed by the sampling module 12 is as follows:

[0102] ,

[0103] in, represents the sampling time interval, Indicates the sampling accuracy, Indicates the rated capacity of the battery. Indicates the accuracy of the state of charge, Indicates the acquisition current, Indicates the open circuit voltage accuracy.

[0104] In an exemplary embodiment, the equation for recording the state of charge after standing still 11 is as follows:

[0105] ,

[0106] in, Indicates the recorded state of charge after resting. It indicates the state of charge corresponding to the current open circuit voltage, t indicates a time period, I indicates the collected current, Indicates the rated capacity of the battery.

[0107] In an exemplary embodiment, the formula for the state of charge correction module 13 to correct the reference state of charge is as follows:

[0108] ,

[0109] in, represents the corrected reference state of charge, It is the state of charge corresponding to the open circuit voltage when recording the reference state of charge. is the reference state of charge, It is the state of charge corresponding to the most recently recorded open circuit voltage when entering the static state again. It is the latest recorded state of charge after the static state when entering the static state again.

[0110] In an exemplary embodiment, the modified impedance calculation module 14 calculates the equivalent resistance using the following formula:

[0111] ,

[0112] in, represents the equivalent impedance, represents the open circuit voltage corresponding to the corrected reference state of charge, Indicates the constant current voltage corresponding to the corrected reference state of charge, Indicates the constant current corresponding to the corrected reference state of charge.

[0113] In an exemplary embodiment, the modified impedance calculation module 14 calculates the modified impedance according to the following formula:

[0114] Ris_Step=|Ris_Now-Ristn_true |*η,

[0115] Among them, Ris_Step represents the corrected impedance, Ris_Now represents the calibrated impedance, Risn_true represents the equivalent impedance, and η represents the confidence level, which is between 0 and 1.

[0116] In an exemplary embodiment, the updating module 15 updates the corresponding calibrated impedance using the corrected impedance according to the polarization mark corresponding to the reference state of charge, including:

[0117] When the polarization flag indicates that the voltage change rate is greater than the open circuit voltage change rate, and Ris_Now is less than Risn_true, Ris_New = Ris_Now + Ris_Step;

[0118] When the polarization flag indicates that the voltage change rate is less than the open circuit voltage change rate, and Ris_Now is greater than Risn_true, Ris_New = Ris_Now-Ris_Step;

[0119] When the polarization flag indicates that the voltage change rate is equal to or approximately equal to the open circuit voltage change rate, if Ris_Now is less than Risn_true, Ris_New=Ris_Now+Ris_Step; if Ris_Now is greater than Risn_true, Ris_New=Ris_Now-Ris_Step;

[0120] Wherein, Ris_New represents the updated calibrated impedance.

[0121] Figure 4 is a schematic diagram of the hardware structure of an electronic device for performing an online battery impedance identification method provided by an embodiment of the present invention, such as Figure 4 As shown, the device includes:

[0122] One or more processors 410 and memory 420, Figure 4 A processor 410 is taken as an example.

[0123] The device for executing the battery impedance online identification method may further include: an input device 430 and an output device 440 .

[0124] The processor 410, the memory 420, the input device 430 and the output device 440 may be connected via a bus or other means. Figure 4 The example of connecting through bus is taken in the following.

[0125] The memory 420 is a non-volatile computer-readable storage medium that can be used to store non-volatile software programs, non-volatile computer executable programs and modules, such as the program instructions / modules corresponding to the battery impedance online identification method in the embodiment of the present invention (for example, the attached Figure 3 The processor 410 executes various functional applications and data processing of the server by running the non-volatile software programs, instructions and modules stored in the memory 420, that is, the battery impedance online identification method of the above method embodiment is realized.

[0126] The memory 420 may include a program storage area and a data storage area, wherein the program storage area may store an operating system and application programs required for at least one function; the data storage area may store data created according to the use of the battery impedance online identification device, etc. In addition, the memory 420 may include a high-speed random access memory, and may also include a non-volatile memory, such as at least one disk storage device, a flash memory device, or other non-volatile solid-state storage device. In some embodiments, the memory 420 may optionally include a memory remotely arranged relative to the processor 410, and these remote memories may be connected to the battery impedance online identification device via a network. Examples of the above-mentioned network include, but are not limited to, the Internet, an intranet, a local area network, a mobile communication network, and combinations thereof.

[0127] The input device 430 can receive input digital or character information and generate key signal input related to user settings and function control of the battery impedance online identification device. The output device 440 can include display devices such as a display screen.

[0128] The one or more modules are stored in the memory 420, and when executed by the one or more processors 410, the battery impedance online identification method in any of the above method embodiments is executed.

[0129] The above product can execute the method provided by the embodiment of the present invention, and has the functional modules and beneficial effects corresponding to the execution method. For technical details not described in detail in this embodiment, please refer to the method provided by the embodiment of the present invention.

[0130] The electronic device of the embodiment of the present invention exists in various forms, including but not limited to:

[0131] (1) Mobile communication devices: These devices are characterized by their mobile communication functions and their main purpose is to provide voice and data communications. These terminals include: smart phones (such as iPhone), multimedia phones, functional phones, and low-end phones.

[0132] (2) Ultra-mobile personal computer devices: These devices fall into the category of personal computers, have computing and processing capabilities, and generally also have mobile Internet access features. These terminals include: PDA, MID and UMPC devices, such as iPad.

[0133] (3) Portable entertainment devices: These devices can display and play multimedia content. They include audio and video players (such as iPods), handheld game consoles, e-books, smart toys, and portable car navigation devices.

[0134] (4) Server: A device that provides computing services. The server consists of a processor, hard disk, memory, system bus, etc. The server is similar to a general computer architecture, but because it needs to provide highly reliable services, it has higher requirements in terms of processing power, stability, reliability, security, scalability, and manageability.

[0135] (5) Other electronic devices with data interaction functions.

[0136] The device embodiments described above are merely illustrative, wherein the units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, i.e., they may be located in one place or distributed over multiple network units. Some or all of the modules may be selected according to actual needs to achieve the purpose of the present embodiment.

[0137] Each embodiment in this specification is described in a progressive manner, and the same or similar parts between the embodiments can be referred to each other, and each embodiment focuses on the differences from other embodiments. In particular, for the device or system embodiment, since it is basically similar to the method embodiment, the description is relatively simple, and the relevant parts can be referred to the partial description of the method embodiment. The device and system embodiments described above are merely schematic, wherein the units described as separate components may or may not be physically separated, and the components displayed as units may or may not be physical units, that is, they may be located in one place, or they may be distributed on multiple network units. Some or all of the modules may be selected according to actual needs to achieve the purpose of the scheme of this embodiment. Ordinary technicians in this field can understand and implement it without paying creative labor.

[0138] It should be noted that, in this article, relational terms such as "first" and "second" are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "comprise a ..." do not exclude the existence of other identical elements in the process, method, article or device including the elements.

[0139] The above description is only a specific embodiment of the present invention, so that those skilled in the art can understand or implement the present invention. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but should conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A battery impedance online identification method, characterized in that: include: When the battery meets the static state, the open circuit voltage is collected and the state of charge after static state is calculated. The state of charge after static state is the difference between the state of charge corresponding to the current open circuit voltage and the time integral of the collected current relative to the ratio of the rated capacity of the battery; When the battery meets the constant current state, the state of charge after standing, the constant current, the constant current voltage and the polarization mark are recorded according to the sampling time interval; wherein the sampling time interval is the time interval calculated by the sampling accuracy, the open circuit voltage accuracy, the state of charge accuracy, the collection current and the rated capacity of the battery; the polarization mark represents the numerical relationship between the voltage change rate and the open circuit voltage change rate; When the battery meets the static state again, the reference state of charge obtained by recording data in the constant current state is corrected according to the latest calculated state of charge after static state, wherein the reference state of charge is the last value of the state of charge after static state recorded in the constant current state, or the value after sliding window filtering or average filtering of all the state of charge after static state recorded in the constant current state; The corrected reference state of charge corresponds to a reference open circuit voltage, an equivalent impedance is obtained from the reference open circuit voltage, and a corrected impedance is calculated based on the equivalent impedance, wherein the corrected impedance is the product of a difference between the calibrated impedance and the equivalent impedance and a confidence level; According to the polarization sign corresponding to the reference state of charge, the corresponding calibration impedance is updated using the corrected impedance.

2. The battery impedance online identification method according to claim 1, characterized in that: The calculation formula of the sampling time interval is as follows: , in, represents the sampling time interval, Indicates the sampling accuracy, Indicates the rated capacity of the battery. Indicates the acquisition current Indicates the rate of change of state of charge with respect to open circuit voltage.

3. The battery impedance online identification method according to claim 1, characterized in that: The calculation formula for recording the state of charge after standing is as follows: , in, Indicates the recorded state of charge after resting. It indicates the state of charge corresponding to the current open circuit voltage, t indicates a time period, I indicates the collected current, Indicates the rated capacity of the battery.

4. The battery impedance online identification method according to claim 1, characterized in that: The corrected reference state of charge calculation formula is as follows: , in, represents the corrected reference state of charge, It is the state of charge corresponding to the open circuit voltage when recording the reference state of charge. is the reference state of charge, It is the state of charge corresponding to the most recently recorded open circuit voltage when entering the static state again. It is the latest recorded state of charge after the static state when entering the static state again.

5. The battery impedance online identification method according to claim 1, characterized in that: The corrected reference state of charge corresponds to a reference open circuit voltage, and the equivalent impedance is obtained from the reference open circuit voltage. The calculation formula is as follows: , in, represents the equivalent impedance, represents the open circuit voltage corresponding to the corrected reference state of charge, Indicates the constant current voltage corresponding to the corrected reference state of charge, Indicates the constant current corresponding to the corrected reference state of charge.

6. The battery impedance online identification method according to claim 1, characterized in that: The modified impedance is calculated based on the equivalent impedance, and the formula is as follows: Ris_Step=|Ris_Now-Ristn_true |*η Among them, Ris_Step represents the corrected impedance, Ris_Now represents the calibrated impedance, Risn_true represents the equivalent impedance, and η represents the confidence level, which is between 0 and 1.

7. The battery impedance online identification method according to claim 6, characterized in that: The method of updating the corresponding calibrated impedance using the corrected impedance according to the polarization mark corresponding to the reference state of charge includes: When the polarization flag indicates that the voltage change rate is greater than the open circuit voltage change rate, and Ris_Now is less than Risn_true, then Ris_New = Ris_Now + Ris_Step; When the polarization flag indicates that the voltage change rate is less than the open circuit voltage change rate, and Ris_Now is greater than Risn_true, then Ris_New=Ris_Now-Ris_Step; When the polarization flag indicates that the voltage change rate is equal to the open circuit voltage change rate, if Ris_Now is less than Risn_true, then Ris_New=Ris_Now+Ris_Step; if Ris_Now is greater than Risn_true, then Ris_New=Ris_Now-Ris_Step; Wherein, Ris_New represents the updated calibrated impedance.

8. A battery impedance online identification device, characterized in that: include: A post-stationary state-of-charge recording module is used to collect the open circuit voltage and calculate the post-stationary state-of-charge when the battery meets the stationary state. The post-stationary state-of-charge is the difference between the state-of-charge corresponding to the current open circuit voltage and the time integral of the collected current relative to the ratio of the rated capacity of the battery; A sampling module, used for recording the state of charge after standing, constant current, constant current voltage and polarization mark according to the sampling time interval when the battery meets the constant current state; wherein the sampling time interval is the time interval calculated by the sampling accuracy, open circuit voltage accuracy, state of charge accuracy, collection current and battery rated capacity; the polarization mark represents the numerical relationship between the voltage change rate and the open circuit voltage change rate; A state of charge correction module, used to correct the reference state of charge obtained by recording data in the constant current state according to the latest calculated state of charge after the static state when the battery meets the static condition again, wherein the reference state of charge is the last value of the state of charge after the static state recorded in the constant current state, or the value of all the state of charge after the static state recorded in the constant current state after sliding window filtering or average filtering; A corrected impedance calculation module, used for the corrected reference state of charge corresponding to the reference open circuit voltage, obtaining the equivalent impedance from the reference open circuit voltage, and calculating the corrected impedance according to the equivalent impedance, wherein the corrected impedance is the product of the difference between the calibrated impedance and the equivalent impedance and the confidence level; The updating module is used to update the corresponding calibration impedance using the corrected impedance according to the polarization mark corresponding to the reference charge state.

9. An electronic device, characterized in that: The method comprises a memory and a processor, wherein a computer program is stored in the memory, and when the processor executes the computer program, the steps of the battery impedance online identification method as described in any one of claims 1 to 7 are implemented.

10. A computer-readable storage medium, characterized in that: The storage medium stores at least one instruction, at least one program, a code set or an instruction set, and the at least one instruction, the at least one program, the code set or the instruction set is loaded and executed by the processor to implement the steps of the battery impedance online identification method as described in any one of claims 1 to 7.

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