A method for estimating the capacity of a power battery, an electronic device, and a storage medium.

Abstract

This invention discloses a method for estimating the capacity of a power battery, an electronic device, and a storage medium. The method includes: acquiring a first relationship curve between the recovery time and the recovery ratio of a battery module after a relay is disconnected; acquiring first voltage recovery data for each battery module during the preparation phase and second voltage recovery data during the end phase, wherein the voltage recovery data includes voltage data at the beginning and end of the phase and the duration elapsed; for each battery module, using the first relationship curve as a reference, calculating the first open-circuit voltage before charging and the second open-circuit voltage after charging based on the first voltage recovery data and the second voltage recovery data; determining the first state of charge (SOC) before charging and the second SOC after charging based on the first and second SOCs; calculating the remaining capacity of the power battery based on the first and second SOCs of all battery modules; and enabling estimation of open-circuit voltage and remaining capacity in a short time.

Description

Technical Field

[0001] This invention relates to the field of battery management technology, and in particular to a method for estimating the capacity of a power battery, an electronic device, and a storage medium. Background Technology

[0002] Power equipment can be powered by a battery. During operation, a Battery Management System (BMS) is required to provide real-time state of charge (SOC) data. Estimating the remaining battery capacity helps monitor battery aging. When the remaining capacity decays to a preset percentage of the initial value (e.g., 80%), the battery's lifespan is generally considered to have ended. By monitoring capacity changes in real time, preventative measures, such as adjusting charging and discharging strategies, can be taken to extend battery life. Furthermore, battery capacity estimation helps the BMS detect battery anomalies promptly. However, if the estimated capacity deviates significantly from the actual value, it may indicate a battery malfunction or safety hazard, necessitating timely intervention. Therefore, accurate estimation of the remaining battery capacity is crucial.

[0003] Existing technologies mainly use the OCV-SOC curve correction method to estimate the remaining capacity of the battery. The OCV-SOC curve is derived from the open-circuit voltage of the power battery corresponding to different SOCs. However, the open-circuit voltage of the power battery needs to be left to stand for a considerable period of time after power is cut off before it stabilizes. It is difficult to meet this standing time condition during the battery charging process. Therefore, the calculated open-circuit voltage and remaining capacity have large errors. Summary of the Invention

[0004] This invention provides a method for estimating the capacity of a power battery, in order to solve the problem that the long resting time required for open-circuit voltage in the prior art leads to large errors in the calculated open-circuit voltage and remaining capacity.

[0005] In a first aspect, the present invention provides a method for estimating the capacity of a power battery. The power battery charging process includes a preparation stage, a charging stage, and an ending stage. In the preparation stage, the battery management system (BMS) first controls a relay to disconnect, and at the end of the preparation stage, the BMS controls the relay to close, subsequently entering the charging stage. In the ending stage, the BMS controls the relay to disconnect for a preset second duration. The power battery includes multiple battery modules, and the method includes:

[0006] Obtain a first relationship curve between the recovery time and the recovery ratio of the battery module after the relay is disconnected, wherein the recovery ratio is the ratio of the module voltage recovery value at different recovery times to the total module voltage recovery value;

[0007] Acquire first voltage recovery data for each battery module during the preparation phase. The first voltage recovery data includes the first module voltage, the second module voltage, and the first duration of the preparation phase at the beginning and end of the preparation phase.

[0008] Acquire second voltage recovery data for each battery module in the end phase, the second voltage recovery data including the third module voltage, the fourth module voltage, and the second duration at the beginning and end of the end phase of the battery module;

[0009] For each battery module, with the first relationship curve as a reference, the first open-circuit voltage before charging and the second open-circuit voltage after charging are calculated based on the first voltage recovery data and the second voltage recovery data, respectively.

[0010] The first state of charge before charging and the second state of charge after charging of the battery module are determined based on the first open-circuit voltage and the second open-circuit voltage, respectively.

[0011] The remaining capacity of the power battery is calculated based on the first state of charge and the second state of charge of all the battery modules.

[0012] Secondly, the present invention provides a power battery capacity estimation device.

[0013] The power battery charging process includes a preparation phase, a charging phase, and an ending phase. In the preparation phase, the BMS first controls the relay to open, and at the end of the preparation phase, the BMS controls the relay to close, subsequently entering the charging phase. In the ending phase, the BMS controls the relay to open for a preset second duration. The power battery includes multiple battery modules.

[0014] The device includes:

[0015] The first relationship curve acquisition module is used to acquire the first relationship curve between the recovery time and the recovery ratio of the battery module after the relay is disconnected. The recovery ratio is the ratio of the module voltage recovery value of the battery module at different recovery times to the total module voltage recovery value.

[0016] The first voltage recovery data module is used to acquire first voltage recovery data for each battery module during the preparation phase. The first voltage recovery data includes the first module voltage, the second module voltage, and the first duration of the preparation phase at the beginning and end of the preparation phase.

[0017] The second voltage recovery data module is used to acquire the second voltage recovery data of each battery module in the end phase. The second voltage recovery data includes the third module voltage, the fourth module voltage, and the second duration at the beginning and end of the end phase of the battery module.

[0018] An open-circuit voltage determination module is used to calculate, for each battery module, the first open-circuit voltage before charging and the second open-circuit voltage after charging, respectively, based on the first voltage recovery data and the second voltage recovery data, with the first relationship curve as a reference.

[0019] A state of charge determination module is used to determine the first state of charge of the battery module before charging and the second state of charge after charging based on the first open-circuit voltage and the second open-circuit voltage, respectively.

[0020] The remaining capacity calculation module is used to calculate the remaining capacity of the power battery based on the first state of charge and the second state of charge of all the battery modules.

[0021] Thirdly, the present invention provides an electronic device, the electronic device comprising:

[0022] At least one processor; and

[0023] A memory communicatively connected to the at least one processor; wherein,

[0024] The memory stores a computer program that can be executed by the at least one processor, the computer program being executed by the at least one processor to enable the at least one processor to perform the power battery capacity estimation method described in the first aspect of the present invention.

[0025] Fourthly, the present invention provides a computer-readable storage medium storing computer instructions that, when executed by a processor, implement the power battery capacity estimation method described in the first aspect of the present invention.

[0026] The present invention provides a method for estimating the capacity of a power battery, the beneficial effects of which are as follows:

[0027] First, obtain the first relationship curve between the recovery time and recovery ratio of the battery module after the relay is disconnected. The recovery ratio is the ratio of the module voltage recovery value of the battery module at different recovery times to the total module voltage recovery value. Therefore, given the module voltage of the battery module after a certain recovery time, the ratio of the module voltage recovery value to the open-circuit voltage of the total module voltage recovery value can be determined. In the preparation stage (before charging) and the end stage (after charging), detect the voltage data and duration of the battery module at the beginning and end of the current stage, and determine the relationship between the module voltage at the beginning and end of the current stage and the corresponding open-circuit voltage based on the first relationship curve. This system allows for the calculation of the open-circuit voltage at the current stage based on the module voltages at the beginning and end points and the relevant formula. This yields the first open-circuit voltage before charging (preparation stage) and the second open-circuit voltage after charging (end stage). The first and second open-circuit voltages determine the first state of charge (SOC) before charging and the second SOC after charging, respectively. Furthermore, the remaining capacity of the power battery can be calculated based on the SOC and SOC of all battery modules, eliminating the need for a long resting period and reducing estimation errors. Moreover, this solution calculates the remaining capacity of the power battery for each battery module's SOC and SOC, taking into account the differences between each module and further reducing estimation errors.

[0028] It should be understood that the description in this section is not intended to identify key or essential features of the embodiments of the present invention, nor is it intended to limit the scope of the invention. Other features of the invention will become readily apparent from the following description. Attached Figure Description

[0029] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0030] Figure 1 This is a schematic diagram illustrating the voltage changes of a battery module during discharge and after power failure, provided by an embodiment of the present invention.

[0031] Figure 2 This is a flowchart of a power battery capacity estimation method provided in an embodiment of the present invention;

[0032] Figure 3 This is a schematic diagram of a first relationship curve provided in an embodiment of the present invention;

[0033] Figure 4This is a schematic diagram of a second relationship curve provided in an embodiment of the present invention;

[0034] Figure 5 This is a flowchart of a power battery remaining capacity calculation method provided in an embodiment of the present invention;

[0035] Figure 6 This is a flowchart of a remaining capacity update method provided in an embodiment of the present invention;

[0036] Figure 7 This is a schematic diagram of the structure of a power battery capacity estimation device provided in an embodiment of the present invention;

[0037] Figure 8 This is a schematic diagram of the structure of the electronic device provided in an embodiment of the present invention. Detailed Implementation

[0038] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0039] This invention provides a method for estimating the capacity of a power battery. This embodiment is applicable to situations involving power battery capacity estimation. The method can be executed by a power battery capacity estimation device, which can be implemented in hardware and / or software and can be configured in an electronic device.

[0040] In this embodiment of the invention, the power device is powered by a power battery, which includes multiple battery modules, each of which may include one or more individual battery cells. Each battery module has the same or similar remaining capacity at the time of manufacture, but after a period of use, the remaining capacity of different battery modules may exhibit performance differences. The remaining capacity of the power battery can be calculated based on the state of charge (SOC) of the battery modules. Therefore, to reduce the error in estimating the remaining capacity of the power battery, the SOC of each battery module is first estimated. Specifically, the power battery in this embodiment of the invention can be a lithium battery.

[0041] The battery module voltage gradually increases during charging and gradually decreases during discharging. Only after power is cut off (current is 0) will the battery module voltage gradually recover to the open circuit voltage. Figure 1 This is a schematic diagram illustrating the voltage changes of a battery module during discharge and after power failure, as shown below. Figure 1 As shown:

[0042] Segment AB (excluding point B) represents the discharge process, during which the voltage of the battery module continuously decreases. Point B marks the moment of power failure. Segment BC represents the voltage recovery process after power failure. Point C marks the point corresponding to the open-circuit voltage, and the voltage remains constant after point C.

[0043] In segment BC, the interaction current between the battery module and the external device is zero, but the net current inside the battery module is not zero, so the voltage is constantly changing. When the battery module enters the open-circuit state, the internal charge distribution reaches equilibrium, so no net current is generated, and the voltage remains stable. It can be seen that the voltage of the battery module can only gradually recover to the open-circuit voltage and remain at that open-circuit voltage after power failure. However, it takes a long recovery time (resting time) from point B at the moment of power failure to point C at the moment of recovery to the open-circuit voltage. During the charging period of the power battery, it is difficult to have such a long time for the battery module to recover its voltage. Therefore, a method for estimating the open-circuit voltage with less time consumption and smaller error is needed to estimate the open-circuit voltage of the battery module before and after charging, and then calculate the remaining capacity of the power battery based on the open-circuit voltage of the battery module before and after charging.

[0044] Considering the need to estimate the open-circuit voltage of the battery module before and after charging, the power battery charging in this invention includes a preparation stage, a charging stage, and an end stage, corresponding to the states before charging, during charging, and after charging, respectively. In the preparation stage, the BMS first controls the relay to open, and at the end of the preparation stage, the BMS controls the relay to close, thus entering the charging stage. In the end stage, the BMS controls the relay to open for a preset second duration. It should be noted that in the prior art, at the end of the charging stage, the relay can remain closed to allow the power battery to discharge, i.e., the power equipment enters a standby state. This embodiment sets an end stage, in which the relay is controlled to open for a preset second duration to provide the battery module with a certain recovery time.

[0045] In this embodiment of the invention, the battery module has a short recovery time during both the preparation stage (before charging) and the end stage (after charging). The open-circuit voltage of the battery module is estimated based on this short recovery time, and then the remaining capacity of the power battery is calculated based on the open-circuit voltage of all battery modules.

[0046] Figure 2 A flowchart of a power battery capacity estimation method provided in an embodiment of the present invention is shown below. Figure 2 As shown, the method for estimating the capacity of a power battery includes:

[0047] S201. Obtain the first relationship curve between the recovery time and the recovery ratio of the battery module after the relay is disconnected.

[0048] The recovery ratio is the ratio of the module voltage recovery value to the total module voltage recovery value at different recovery times. The first relationship curve can be standard data provided by the battery manufacturer, and it can be obtained by fitting historical voltage recovery data of battery module samples of the same model.

[0049] Figure 3 This is a schematic diagram of a first relationship curve. Figure 3 In the diagram, the horizontal axis represents the recovery time, and the vertical axis represents the recovery ratio. Given the recovery time of the battery module after a power outage, the ratio of the module voltage recovery value corresponding to the recovery time to the total module voltage recovery value can be determined, which represents the degree of voltage recovery of the battery module.

[0050] S202. Obtain the first voltage recovery data of each battery module during the preparation phase. The first voltage recovery data includes the first module voltage, the second module voltage, and the first duration of the preparation phase at the beginning and end of the preparation phase.

[0051] During the preparation phase, the BMS first controls the relay to open, and at the end of the preparation phase, the BMS controls the relay to close, subsequently initiating the charging phase. The BMS can detect both the relay opening and closing moments; the duration from opening to closing is the first time interval. Furthermore, the BMS can also detect the battery module voltage at the relay opening and closing moments, i.e., the first module voltage and the second module voltage.

[0052] Regarding S201-S202, for example, the power equipment is an electric vehicle, and the process of scanning the code to charge the power battery of the electric vehicle at the charging station and collecting vehicle data is as follows:

[0053] After the vehicle control unit (VCU) detects the fast charging gun being inserted, it requests the battery management system (BMS) to disconnect the relay (thus entering the preparation phase). When the BMS disconnects the relay, the current is 0, and the battery module voltage is the first module voltage V1. Timing begins, and then the user scans the code to charge, and the vehicle interacts with the charging pile according to the national standard charging process. When the BRO 00 message is received, the national standard requires the BRO AA message to be sent within 60 seconds. The condition for sending the BRO AA message is that the relay is already closed. To allow the battery module a sufficiently long resting time, the BMS can control the relay to close at 45 seconds. Simultaneously with the relay closing, the BRO AA message is sent to the charging pile, and the timing ends, obtaining the first duration T1. At this time, the battery module voltage is the second module voltage V2. The BRO 00 message indicates that charging preparation is not yet complete, while the BRO AA message indicates that charging preparation is complete.

[0054] S203. Obtain the second voltage recovery data of each battery module at the end stage. The second voltage recovery data includes the third module voltage, the fourth module voltage, and the second duration at the beginning and end of the end stage of the battery module.

[0055] When the preset charging termination conditions are met, the system enters the termination phase, controlling the relay to disconnect. The BMS can detect the initial voltage of the battery module in the termination phase, i.e., the third module voltage V3. After the relay disconnection time reaches the preset second duration, the fourth module voltage V4 is detected, thus completing the acquisition of the required data. The preset charging termination condition can be that the State of Charge (SOC) reaches a preset state of charge threshold and the charging pile no longer outputs current. The preset state of charge threshold can be 90%. The second duration depends on the battery characteristics. After charging is completed and the relay disconnects, the vehicle does not have high-voltage operating conditions, but the BMS remains operational. To avoid battery depletion, the second duration should not be too long. For example, the second duration is set to 120 seconds. These parameters are merely examples and are not intended to limit the invention.

[0056] In the final stage, the BMS controls the relay to disconnect and the disconnection time reaches the preset second duration. The duration of the final stage is the second duration. The BMS can also detect the battery module voltage at the moment the relay disconnects and when the disconnection time reaches the second duration, which are the third and fourth module voltages.

[0057] S204. For each battery module, with the first relationship curve as a reference, calculate the first open-circuit voltage of the battery module before charging and the second open-circuit voltage after charging based on the first voltage recovery data and the second voltage recovery data.

[0058] Specifically, this includes: determining the recovery ratios corresponding to the first duration and the second duration in the first relationship curve, respectively, to obtain the first recovery ratio and the second recovery ratio; calculating the first open-circuit voltage of the battery module before charging based on the first module voltage, the second module voltage, and the first recovery ratio; and calculating the second open-circuit voltage of the battery module after charging based on the third module voltage, the fourth module voltage, and the second recovery ratio.

[0059] Regarding the preparation phase, its duration is designated as the first duration. The real-time voltage of the battery module corresponding to the first duration is the second module voltage. The recovery ratio corresponding to the first duration is obtained from the first relationship curve, which is the ratio of the second module voltage to the open-circuit voltage of the battery module before charging (the first open-circuit voltage). The recovery duration corresponding to the first module voltage is 0, which is the initial module voltage of the preparation phase. Therefore, the first module voltage is the starting voltage of the voltage recovery curve (first relationship curve) containing the second module voltage and the first open-circuit voltage. The first open-circuit voltage is then calculated according to the following formula:

[0060]

[0061] Where OCV1 is the first open-circuit voltage, V1 is the first module voltage, V2 is the second module voltage, V2-V1 is the module voltage recovery value of the second module voltage V2 relative to the first module voltage V1, OCV1-V1 is the module voltage recovery value of the first open-circuit voltage OCV1 relative to the first module voltage V1, i.e., the total module voltage recovery value, and α1 is the ratio of the module voltage recovery value at the second module voltage V2 to the total module voltage recovery value at the first open-circuit voltage OCV1. Transforming this formula yields:

[0062] OCV1=V1+(V2-V1) / α1

[0063] In this formula, V1, V2 and α1 are all known values, so the first open-circuit voltage OCV1 can be calculated.

[0064] Regarding the final stage, its duration is the second duration, and the real-time voltage of the battery module corresponding to the second duration is the fourth module voltage. The recovery ratio corresponding to the second duration is obtained from the first relationship curve, which is the ratio of the recovered module voltage of the fourth module to the total recovered module voltage of the open-circuit voltage (second open-circuit voltage) after battery module charging. The recovery duration corresponding to the third module voltage is 0, which is the initial module voltage of the final stage. Therefore, the third module voltage is the starting voltage of the voltage recovery curve (first relationship curve) containing the fourth module voltage and the second open-circuit voltage. Combining the second duration, the second open-circuit voltage is calculated. Referring to the calculation formula for the first open-circuit voltage mentioned above, the calculation formula for the second open-circuit voltage is obtained as follows:

[0065] OCV2=V3+(V4-V3) / α2

[0066] Wherein, OCV2 is the second open-circuit voltage, V3 is the third module voltage, V4 is the fourth module voltage, V4-V3 is the module voltage recovery value of the fourth module voltage V4 relative to the third module voltage V3, and α2 is the ratio of the module voltage recovery value when the fourth module voltage is V4 to the total module voltage recovery value when the second open-circuit voltage is OCV2.

[0067] In this formula, V3, V4 and α2 are all known values, so the second open-circuit voltage OCV2 can be calculated.

[0068] S205. Determine the first state of charge of the battery module before charging and the second state of charge after charging based on the first open-circuit voltage and the second open-circuit voltage, respectively.

[0069] Specifically, this includes: obtaining a second relationship curve between the open-circuit voltage and the state of charge corresponding to the battery module; determining the state of charge corresponding to the first open-circuit voltage and the second open-circuit voltage in the second relationship curve respectively, to obtain the first state of charge before charging and the second state of charge after charging.

[0070] The second relationship curve can be standard data provided by the battery manufacturer, or it can be obtained by testing samples of the same model of battery module. Furthermore, in this invention, the first and second relationship curves can be corrected according to ambient temperature and updated as the power battery is used.

[0071] Figure 4 This is a schematic diagram of a second relationship curve; in Figure 4 In the second relationship curve, the horizontal axis is SOC (state of charge) and the vertical axis is OCV (open circuit voltage). Given the first open circuit voltage and the second open circuit voltage, the corresponding first and second states of charge can be determined from the second relationship curve.

[0072] S206. Calculate the remaining capacity of the power battery based on the first and second states of charge of all battery modules.

[0073] State of charge (SOC) is a core parameter describing the remaining capacity of a battery, representing the percentage of its current capacity relative to its full capacity.

[0074] In an optional embodiment, the remaining capacity of the power battery is calculated as follows: given the first state of charge and the second state of charge of the battery modules, for each battery module, the capacity charged during the charging phase is obtained, the change range of the state of charge of the battery module is calculated based on the first state of charge and the second state of charge, the remaining capacity of the battery module is calculated based on the change range of the state of charge and the capacity charged during the charging phase (capacity change range), and finally the average value of the remaining capacity of all battery modules is calculated to obtain the remaining capacity of the power battery.

[0075] In this embodiment, the remaining capacity of the power battery

[0076] Where n is the number of battery modules, C i Let dQ be the remaining capacitance of the i-th battery module. i To charge the capacity of the i-th battery module, SOC2 i For the second state of charge of the i-th battery module, SOC1 i This represents the first state of charge of the i-th battery module.

[0077] In another optional embodiment, the remaining capacity of the power battery is calculated as follows: given the first and second states of charge of all battery modules, the total capacity charged into all battery modules during the charging phase (i.e., the total charging capacity of the power battery) is obtained; the average value of all first states of charge and the average value of all second states of charge are calculated; the average value of the change in state of charge of the battery modules in the power battery is calculated based on the average value of all first states of charge and the second states of charge; and the remaining capacity of the power battery is calculated based on the average value of the change in state of charge and the total capacity.

[0078] In this embodiment, the remaining capacity of the power battery

[0079] Among them, dQ all For total charging capacity, SOC2 avg SOC1 is the average of the second state of charge of all battery modules. avg This represents the average first state of charge (SFC) of all battery modules.

[0080] In an optional embodiment, the remaining capacity of the power battery can be estimated when the following conditions are met:

[0081] Condition 1: SOC 始 <40%, SOC 末 >90%, ensuring a sufficiently large SOC change throughout the charging process; where SOC 始 State of charge (SOC) before charging 末 This represents the state of charge after charging.

[0082] Condition 2: When charging is complete, the lowest module temperature inside the battery pack is >15℃. Because battery capacity is closely related to temperature, only when the temperature reaches a certain level will the remaining battery capacity not be too sensitive to temperature, and only then will the estimated remaining capacity be comparable.

[0083] This invention provides a method for estimating the capacity of a power battery. First, a first relationship curve is obtained between the recovery time and recovery ratio of the battery module after the relay is disconnected. The recovery ratio is the ratio of the module voltage to the open-circuit voltage at different recovery times. Therefore, given the module voltage after a certain recovery time, the ratio of the module voltage to the open-circuit voltage can be determined. In the preparation stage (before charging) and the end stage (after charging), the voltage data and duration of the battery module at the beginning and end of the current stage are detected, and the ratio of the module voltage to the corresponding open-circuit voltage at the beginning and end of the current stage is determined by combining the first relationship curve. The open-circuit voltage at the current stage can be calculated based on the module voltage and ratio at the beginning and end of the charging process. This yields the first open-circuit voltage before charging (preparation stage) and the second open-circuit voltage after charging (end stage). The first and second open-circuit voltages determine the first state of charge (SOC) before charging and the second SOC after charging, respectively. Therefore, the remaining capacity of the power battery can be calculated based on the SOC and SOC of all battery modules. This allows for estimation of open-circuit voltage and remaining battery capacity without requiring a long resting time, thus reducing estimation errors. Furthermore, this solution calculates the remaining capacity of the power battery for each battery module's SOC and SOC, taking into account the differences between each module and further reducing estimation errors.

[0084] In an optional embodiment, the first relationship curve can be obtained by fitting historical voltage recovery data of battery module samples of the same model. Obtaining the first relationship curve of the recovery time and recovery ratio of the battery module after the relay is disconnected includes the following steps:

[0085] Historical voltage recovery data of battery module samples with the same model as the battery module is obtained. The historical voltage recovery data is obtained under the condition that the resting time is longer than the preset recovery time. The historical voltage recovery data includes the recovery time and the voltage of the battery module sample corresponding to the recovery time. The maximum voltage and minimum voltage in the historical voltage recovery data are respectively used as the historical open circuit voltage and the historical initial voltage. The difference between the historical open circuit voltage and the historical initial voltage is calculated to obtain the total module voltage recovery value. The difference between the voltage of the battery module sample corresponding to each recovery time and the historical initial voltage is calculated to obtain the module voltage recovery value corresponding to the recovery time. The ratio of the module voltage recovery value corresponding to each recovery time to the total module voltage recovery value is calculated to obtain the recovery ratio corresponding to each recovery time. An initial relationship curve is generated based on the recovery time and the corresponding recovery ratio. The initial relationship curve is fitted using a preset fitting polynomial to obtain the first relationship curve.

[0086] The preset recovery time is greater than or equal to the time required for the battery module sample to enter the open circuit state. If the resting time is greater than the preset recovery time, it means that the historical voltage recovery data was obtained under the condition of a sufficiently long resting time, and the maximum voltage in the historical voltage recovery data is the corresponding open circuit voltage.

[0087] When fitting the initial relationship curve to obtain the first relationship curve, a polynomial fitting can be used. For example, the fitting formula is as follows:

[0088] α=a1x 7 +a2x 6 +a3x 5 +a4x 4 +a5x 3 +a6x 2 +a1x+a0

[0089] Where α is the recovery ratio, x is the recovery time, and a0, a1, a2, a3, a4, a5, and a6 are fitting coefficients.

[0090] In an optional embodiment, the battery module can be controlled to discharge to different module voltages U (corresponding to different initial voltages of the battery module), and then allowed to stand still while voltage recovery data is collected during the standing process. Based on the voltage recovery data, a first relationship curve is obtained, which corresponds to the first relationship curve for battery modules with different U values. When using the first relationship curve to obtain the recovery ratio, if the initial voltage V1 of the battery module is set, a first relationship curve with a U value equal to or close to the initial voltage V1 can be selected to improve the accuracy of the recovery ratio obtained through the first relationship curve.

[0091] In an optional embodiment, such as Figure 5 The flowchart shown illustrates the calculation of the remaining capacity of the power battery. It calculates the remaining capacity based on the first and second states of charge of all battery modules, including:

[0092] S501, Obtain the total charging capacity of the power battery during the charging phase.

[0093] S502. Calculate the mean of all first states of charge and the mean of all second states of charge to obtain the mean of the first state of charge and the mean of the second state of charge.

[0094] S503. Calculate the minimum remaining capacity of the power battery based on the maximum value of the second state of charge, the minimum value of the first state of charge, and the total charging capacity.

[0095] Minimum remaining capacity of power battery

[0096] Among them, SOC2 maxThe maximum value of the second state of charge, SOC1 min dQ is the minimum value of the first state of charge. all This represents the total charging capacity.

[0097] S504. Calculate the average remaining capacity of the power battery based on the average first state of charge, the average second state of charge, and the total charging capacity.

[0098] Average remaining capacity of power batteries

[0099] Among them, SOC2 avg The mean value of the second state of charge, SOC1 avg Let dQ be the mean value of the first state of charge. all This represents the total charging capacity.

[0100] S505. Calculate the remaining capacity of the power battery based on the average remaining capacity, the minimum remaining capacity, and the preset allocation ratio.

[0101] It should be noted that in the above steps, if the order of the steps does not affect the execution of the subsequent steps, then the execution order of the steps is not restricted. The remaining capacity of the power battery is determined by the battery module with the smallest capacity, while the average remaining capacity is calculated based on the average change in state of charge of the battery modules. The calculation method of the average remaining capacity does not take into account the inconsistency of the battery modules within the power battery, thus making the calculated remaining capacity too large. The minimum remaining capacity reflects the inconsistency of the battery modules, but according to the calculation formula of the minimum remaining capacity, SOC2 max SOC1 min The minimum remaining capacity is not determined to be the state of charge of the same battery module. In other words, the minimum remaining capacity is not determined to be the remaining capacity of the worst-performing battery module. The calculation method of the minimum remaining capacity will make the calculated remaining capacity too small. Therefore, the capacity of the power battery can be calculated by combining the average remaining capacity and the minimum remaining capacity.

[0102] The average remaining capacity reflects the state-of-charge characteristics of all battery modules. Therefore, when calculating the capacity of a power battery by combining the average remaining capacity and the minimum remaining capacity, the average remaining capacity accounts for a larger proportion while the minimum remaining capacity accounts for a smaller proportion.

[0103] In an optional embodiment, the remaining capacity of the power battery is C = a*Cavg + b*Cmin; a > b, a + b = 1, for example, a = 0.7, b = 0.3.

[0104] In an optional embodiment, after calculating the remaining capacity of the power battery based on the average remaining capacity, the minimum remaining capacity, and a preset allocation ratio, the method further includes: calculating the capacity difference between the minimum remaining capacity and the average remaining capacity; and determining that the voltage difference of the battery modules in the power battery is abnormal when the capacity difference is greater than a preset capacity difference threshold.

[0105] When the capacity difference exceeds the preset capacity difference threshold, it indicates that the voltage difference of the battery module has significantly reduced the remaining capacity of the power battery, but the overall capacity (average capacity) is still relatively high. Users can be prompted to visit a 4S store for equalization service via SMS or other means to reduce the voltage difference of the battery module and increase the remaining capacity of the power battery.

[0106] In an optional embodiment, after calculating the remaining capacity of the power battery based on the first and second states of charge of all battery modules, the method further includes updating the remaining capacity, such as... Figure 6 The flowchart shown illustrates the remaining capacity update method, which includes:

[0107] S601. Use the currently calculated remaining capacity of the power battery as the initial remaining capacity.

[0108] S602. Obtain first capacity data, which includes the current date D1, the initial remaining capacity, and the first cumulative charging capacity read by the power battery after charging ends on date D1.

[0109] The first cumulative charging capacity refers to the cumulative charging capacity from the date of the first charging of the automatic power battery to date D1.

[0110] S603. Obtain second capacity data, which includes the date D2 of the last charge of the power battery, the historical remaining capacity and the second cumulative charge capacity stored after the charging ended on date D2.

[0111] The historical remaining capacity is the remaining capacity of the power battery calculated after charging ends on date D2;

[0112] The second cumulative charging capacity refers to the cumulative charging capacity from the date of the first charging of the automatic power battery to the end of the charging period on date D2.

[0113] Both the historical remaining capacity and the second cumulative charging capacity are historical capacity data. For power battery charging, the historical capacity data is all for reference. Even if there are multiple chargings on the same day, the remaining capacity and cumulative charging capacity of the power battery calculated after any one of the chargings can be stored as capacity data. Correspondingly, the historical remaining capacity and the second cumulative charging capacity in S603 also need to be associated, that is, they both correspond to the same charging process.

[0114] S604. Determine the reliability of the initial remaining capacity based on the difference between the first capacity data and the second capacity data.

[0115] The initial remaining capacity is an estimate, not a measured value, therefore its reliability needs to be verified. The second capacity data is the capacity data from the last charge, so the reliability of the initial remaining capacity can be determined by combining the differences between the second capacity data and the first capacity data.

[0116] In an optional embodiment, determining the reliability of the initial remaining capacity based on the difference between the first capacity data and the second capacity data includes: calculating the difference between the initial remaining capacity and the historical remaining capacity to obtain a first difference value; calculating the difference between the first cumulative charging capacity and the second cumulative charging capacity to obtain a second difference value; calculating the difference in the number of days between date D1 and date D2; if the first difference value is less than a preset first difference threshold, the reliability of the initial remaining capacity is a preset fixed ratio value; if the first difference value is greater than or equal to the preset first threshold, the reliability of the initial remaining capacity is determined according to the second difference value or the difference in the number of days, and the reliability is positively correlated with the second difference value or the difference in the number of days.

[0117] In this embodiment, the difference between the initial remaining capacity and the historical remaining capacity can be the absolute value of the difference between the initial remaining capacity and the historical remaining capacity, or it can be the ratio of the absolute value of the difference between the two to the historical remaining capacity. Similarly, the difference between the first cumulative charging capacity and the second cumulative charging capacity can be the absolute value of the difference between the two, or it can be the ratio of the absolute value of the difference between the two to the historical remaining capacity.

[0118] First, compare the difference between the initial remaining capacity and the historical remaining capacity. If the first difference value is less than the preset first difference threshold, it means that the difference between the initial remaining capacity and the historical remaining capacity is small. In this case, both the initial remaining capacity and the historical remaining capacity are reliable. Therefore, the ratio between the initial remaining capacity and the historical remaining capacity can be set according to the preset fixed ratio value.

[0119] When the first difference value is greater than or equal to a preset first threshold, it indicates a significant difference between the battery capacity calculated from the previous charge and the current charge. This could be due to various reasons, requiring the combination of different parameters to infer the cause and then determine the reliability of the initial remaining capacity. First, analyzing the second difference value: a smaller second difference value indicates a relatively smaller capacity charged during the current charge phase, potentially leading to a larger error in calculating the initial remaining capacity, thus lower reliability. Conversely, a larger second difference value indicates a relatively larger capacity charged during the current charge phase, potentially leading to a smaller error in calculating the initial remaining capacity, thus higher reliability. Therefore, reliability is positively correlated with the second difference value. Secondly, analyzing the difference in the number of days: during long-term storage, the battery's capacity decays due to internal self-discharge. The larger the difference in the number of days between date D2 and date D1, the more likely the difference is due to a long date interval, resulting in a larger difference between the historical and initial remaining capacities. A longer date interval leads to lower reliability of the historical remaining capacity and higher reliability of the initial remaining capacity, indicating a positive correlation between reliability and the difference in the number of days.

[0120] S605. Update the initial remaining capacity based on credibility and historical remaining capacity.

[0121] Once the reliability of the initial remaining capacity is known, the initial remaining capacity can be updated based on the reliability and the historical remaining capacity.

[0122] For example, the formula for updating the remaining capacity this time is:

[0123] C new =ε×C+(1-ε)×C his

[0124] Among them, C new Let ε be the updated remaining capacity, ε be the confidence level, and C be the initial remaining capacity. his This represents the remaining capacity from the past.

[0125] In an optional example, define: the initial remaining capacity on date D1, and the first cumulative charging capacity C. 1Tot The remaining capacity of the history of date D2 is C. his Second cumulative charging capacity C 2Tot The value of ε is determined based on the following conditions:

[0126] C and C his If the difference is less than or equal to 2%, ε = 0.5;

[0127] C and C his The difference is greater than 2%, and C 1Tot With C 2Tot The difference is less than C 1Tot_1％ ε = 0.3;

[0128] Assuming the battery's capacity decreases by 20% during the first 1000 full charge-slow discharge cycles, then the capacity decreases by 1% every 50 cycles. Therefore, C... 1Tot_1％ = 50 × the capacity of each full charge of the power battery.

[0129] C and C his The difference is greater than 2%, and C 1Tot With C 2Tot The difference is greater than C 1Tot_1％ and less than ε = 0.4;

[0130] C and C his The difference is greater than 2%, and C 1Tot With C 2Tot The difference is greater than C 1Tot_2％ And less than C Tot_4％ ε = 0.6;

[0131] C and C his The difference is greater than 2%, and C 1Tot With C 2Tot The difference is greater than C 1Tot_4％ If the difference between D2 and D1 is greater than 180 days, then ε = 0.8.

[0132] In this embodiment, the reliability of the remaining power obtained from the previous charge is detected by combining the remaining power obtained from the previous charge, and then the remaining power obtained from the current charge is updated, thereby improving the accuracy of the remaining power estimation.

[0133] Corresponding to the power battery capacity estimation method, the present invention also provides a power battery capacity estimation device. The power battery charging includes a preparation stage, a charging stage, and an ending stage. In the preparation stage, the BMS first controls the relay to open, and at the end of the preparation stage, the BMS controls the relay to close, and then the charging stage begins. In the ending stage, the BMS controls the relay to open for a preset second duration. The power battery includes multiple battery modules. Figure 7 This is a schematic diagram of a power battery capacity estimation device provided in Embodiment 3 of the present invention.

[0134] like Figure 7 As shown, the power battery capacity estimation device includes: the device includes:

[0135] The first relationship curve acquisition module 100 is used to acquire the first relationship curve between the recovery time and the recovery ratio of the battery module after the relay is disconnected, wherein the recovery ratio is the ratio of the module voltage recovery value of the battery module at different recovery times to the total module voltage recovery value.

[0136] The first voltage recovery data module 200 is used to acquire first voltage recovery data for each battery module during the preparation phase. The first voltage recovery data includes the first module voltage, the second module voltage, and the first duration of the preparation phase at the beginning and end of the preparation phase.

[0137] The second voltage recovery data module 300 is used to acquire second voltage recovery data for each battery module in the end phase. The second voltage recovery data includes the third module voltage, the fourth module voltage, and the second duration at the beginning and end of the end phase of the battery module.

[0138] The open-circuit voltage determination module 400 is used to calculate, for each battery module, the first open-circuit voltage before charging and the second open-circuit voltage after charging, respectively, based on the first voltage recovery data and the second voltage recovery data, with the first relationship curve as a reference.

[0139] The state of charge determination module 500 is used to determine the first state of charge of the battery module before charging and the second state of charge after charging based on the first open circuit voltage and the second open circuit voltage, respectively.

[0140] The remaining capacity calculation module 600 is used to calculate the remaining capacity of the power battery based on the first state of charge and the second state of charge of all the battery modules.

[0141] Optionally, the first relationship curve acquisition module 100 is used to perform the following steps:

[0142] Historical voltage recovery data of a battery module sample with the same model as the battery module is obtained. The historical voltage recovery data is obtained under the condition that the resting time is longer than the preset recovery time. The historical voltage recovery data includes the recovery time and the voltage of the battery module sample corresponding to the recovery time.

[0143] The maximum voltage and minimum voltage in the historical voltage recovery data are respectively used as the historical open-circuit voltage and the historical initial voltage;

[0144] Calculate the difference between the historical open-circuit voltage and the historical initial voltage to obtain the total module voltage recovery value;

[0145] Calculate the difference between the voltage of the battery module sample corresponding to each recovery time and the historical initial voltage to obtain the module voltage recovery value corresponding to the recovery time;

[0146] Calculate the ratio of the module voltage recovery value corresponding to each recovery duration to the total module voltage recovery value to obtain the recovery ratio corresponding to each recovery duration;

[0147] An initial relationship curve is generated based on the recovery duration and the corresponding recovery ratio;

[0148] The initial relationship curve is fitted using a preset fitting polynomial to obtain the first relationship curve of the battery module.

[0149] Optionally, the open-circuit voltage determination module 400 is used to perform the following steps:

[0150] The recovery ratios corresponding to the first duration and the second duration are determined from the first relationship curve to obtain the first recovery ratio and the second recovery ratio.

[0151] Calculate the first open-circuit voltage of the battery module before charging based on the first module voltage, the second module voltage, and the first recovery ratio;

[0152] The second open-circuit voltage of the battery module after charging is calculated based on the voltage of the third module, the voltage of the fourth module, and the second recovery ratio.

[0153] Optionally, the state of charge determination module 500 is used to perform the following steps:

[0154] Obtain the second relationship curve between the open-circuit voltage and the state of charge of the battery module;

[0155] The states of charge corresponding to the first open-circuit voltage and the second open-circuit voltage are determined in the second relationship curve, respectively, to obtain the first state of charge of the battery module before charging and the second state of charge after charging.

[0156] Optionally, the remaining capacity calculation module 600 includes:

[0157] The total charging capacity acquisition submodule is used to acquire the total charging capacity of the power battery charged during the charging phase.

[0158] The state mean calculation submodule is used to calculate the mean of all the first charge states and the mean of all the second charge states respectively, so as to obtain the mean of the first charge state and the mean of the second charge state.

[0159] The minimum remaining capacity calculation submodule is used to calculate the minimum remaining capacity of the power battery based on the maximum value of the second state of charge, the minimum value of the first state of charge, and the total charging capacity.

[0160] The average remaining capacity calculation submodule is used to calculate the average remaining capacity of the power battery based on the first average state of charge, the second average state of charge, and the total charging capacity.

[0161] The remaining capacity calculation submodule is used to calculate the remaining capacity of the power battery based on the average remaining capacity, the minimum remaining capacity, and a preset allocation ratio.

[0162] Optionally, the remaining capacity calculation module 600 further includes:

[0163] The capacity difference calculation submodule is used to calculate the capacity difference between the minimum remaining capacity and the first remaining capacity;

[0164] The voltage difference abnormality judgment submodule is used to determine the voltage difference abnormality of the battery module in the power battery when the capacity difference is greater than a preset capacity difference threshold.

[0165] Optionally, the remaining capacity calculation module 600 further includes:

[0166] The initial remaining capacity determination submodule is used to take the currently calculated remaining capacity of the power battery as the initial remaining capacity;

[0167] The first capacity data acquisition submodule is used to acquire first capacity data, which includes the current date D1, the initial remaining capacity, and the first cumulative charging capacity read by the power battery after charging on date D1.

[0168] The second capacity data acquisition submodule is used to acquire second capacity data, which includes the date D2 of the last charge of the power battery, the historical remaining capacity and the second cumulative charge capacity stored after the charging ended on date D2.

[0169] A credibility determination submodule is used to determine the credibility of the initial remaining capacity based on the difference between the first capacity data and the second capacity data;

[0170] The initial remaining capacity update submodule is used to update the initial remaining capacity based on the credibility and the historical remaining capacity.

[0171] Optionally, the initial remaining capacity update submodule is used to perform the following steps:

[0172] Calculate the difference between the initial remaining capacity and the historical remaining capacity to obtain a first difference value;

[0173] Calculate the difference between the first cumulative charging capacity and the second cumulative charging capacity to obtain the second difference value;

[0174] Calculate the difference in the number of days between date D1 and date D2;

[0175] If the first difference value is less than the preset first difference threshold, then the confidence level of the initial remaining capacity is a preset fixed ratio value.

[0176] If the first difference value is greater than or equal to a preset first threshold, the credibility of the initial remaining capacity is determined based on the second difference value or the number of days difference value, and the credibility is positively correlated with the second difference value or the number of days difference value.

[0177] The power battery capacity estimation device provided in this embodiment of the invention can execute the power battery capacity estimation method provided in any embodiment of the invention, and has the corresponding functional modules and beneficial effects of the method.

[0178] Figure 8 A schematic diagram of an electronic device 40 that can be used to implement embodiments of the present invention is shown. The electronic device is intended to represent various forms of digital computers, such as laptop computers, desktop computers, workstations, personal digital assistants, servers, blade servers, mainframe computers, and other suitable computers. The electronic device can also represent various forms of mobile devices, such as personal digital processors, cellular phones, smartphones, and other similar computing devices. The components shown herein, their connections and relationships, and their functions are merely illustrative and are not intended to limit the implementation of the invention described and / or claimed herein.

[0179] like Figure 8 As shown, the electronic device 40 includes at least one processor 41 and a memory, such as a read-only memory (ROM) 42 or a random access memory (RAM) 43, communicatively connected to the at least one processor 41. The memory stores computer programs executable by the at least one processor. The processor 41 can perform various appropriate actions and processes based on the computer program stored in the ROM 42 or loaded into the RAM 43 from storage unit 48. The RAM 43 may also store various programs and data required for the operation of the electronic device 40. The processor 41, ROM 42, and RAM 43 are interconnected via a bus 44. An input / output (I / O) interface 45 is also connected to the bus 44.

[0180] Multiple components in electronic device 40 are connected to I / O interface 45, including: input unit 46; output unit 47, such as various types of displays, speakers, etc.; storage unit 48, such as disks, optical disks, etc.; and communication unit 49, such as network cards, modems, wireless transceivers, etc. Communication unit 49 allows electronic device 40 to exchange information / data with other devices through computer networks such as the Internet and / or various telecommunications networks.

[0181] Processor 41 can be a variety of general-purpose and / or special-purpose processing components with processing and computing capabilities. Some examples of processor 41 include, but are not limited to, a central processing unit (CPU), a graphics processing unit (GPU), various special-purpose artificial intelligence (AI) computing chips, various processors running machine learning model algorithms, a digital signal processor (DSP), and any suitable processor, controller, microcontroller, etc. Processor 41 performs the various methods and processes described above, such as the power battery capacity estimation method.

[0182] In some embodiments, the power battery capacity estimation method may be implemented as a computer program tangibly contained in a computer-readable storage medium, such as storage unit 48. In some embodiments, part or all of the computer program may be loaded and / or installed on electronic device 40 via ROM 42 and / or communication unit 49. When the computer program is loaded into RAM 43 and executed by processor 41, one or more steps of the power battery capacity estimation method described above may be performed. Alternatively, in other embodiments, processor 41 may be configured to perform the power battery capacity estimation method by any other suitable means (e.g., by means of firmware).

[0183] Various embodiments of the systems and techniques described above herein can be implemented in digital electronic circuit systems, integrated circuit systems, field-programmable gate arrays (FPGAs), application-specific integrated circuits (ASICs), application-specific standard products (ASSPs), systems-on-a-chip (SoCs), complex programmable logic devices (CPLDs), computer hardware, firmware, software, and / or combinations thereof. These various embodiments may include implementations in one or more computer programs that can be executed and / or interpreted on a programmable system including at least one programmable processor, which may be a dedicated or general-purpose programmable processor, capable of receiving data and instructions from a storage system, at least one input device, and at least one output device, and transmitting data and instructions to the storage system, the at least one input device, and the at least one output device.

[0184] Computer programs used to implement the methods of the present invention may be written in any combination of one or more programming languages. These computer programs may be provided to a processor of a general-purpose computer, a special-purpose computer, or other programmable data processing device, such that when executed by the processor, the computer programs cause the functions / operations specified in the flowcharts and / or block diagrams to be performed. The computer programs may be executed entirely on a machine, partially on a machine, or as a standalone software package, partially on a machine and partially on a remote machine, or entirely on a remote machine or server.

[0185] In the context of this invention, a computer-readable storage medium can be a tangible medium that may contain or store a computer program for use by or in conjunction with an instruction execution system, apparatus, or device. A computer-readable storage medium may include, but is not limited to, electronic, magnetic, optical, electromagnetic, infrared, or semiconductor systems, apparatus, or devices, or any suitable combination thereof. Alternatively, a computer-readable storage medium may be a machine-readable signal medium. More specific examples of machine-readable storage media include electrical connections based on one or more wires, portable computer disks, hard disks, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), optical fibers, portable compact disk read-only memory (CD-ROM), optical storage devices, magnetic storage devices, or any suitable combination thereof.

[0186] To provide interaction with a user, the systems and techniques described herein can be implemented on an electronic device having: a display device for displaying information to the user (e.g., a monitor with a cathode ray tube or liquid crystal display); and a keyboard and pointing device through which the user provides input to the electronic device. Other types of devices can also be used to provide interaction with the user; for example, the feedback provided to the user can be any form of sensory feedback (e.g., visual feedback, auditory feedback, or tactile feedback); and input from the user can be received in any form (including sound input, voice input, or tactile input).

[0187] The systems and technologies described herein can be implemented in computing systems that include backend components (e.g., as data servers), or computing systems that include middleware components (e.g., application servers), or computing systems that include frontend components (e.g., user computers with graphical user interfaces or web browsers through which users can interact with implementations of the systems and technologies described herein), or any combination of such backend, middleware, or frontend components. The components of the system can be interconnected via digital data communication of any form or medium (e.g., communication networks). Examples of communication networks include local area networks (LANs), wide area networks (WANs), blockchain networks, and the Internet.

[0188] A computing system can include clients and servers. Clients and servers are generally located far apart and typically interact through communication networks. The client-server relationship is created by computer programs running on the respective computers and having a client-server relationship with each other. The server can be a cloud server, also known as a cloud computing server or cloud host, which is a hosting product within the cloud computing service system to address the shortcomings of traditional physical hosts and VPS services, such as high management difficulty and weak business scalability.

[0189] It should be understood that the various forms of processes shown above can be used, with steps reordered, added, or deleted. For example, the steps described in this invention can be executed in parallel, sequentially, or in different orders, as long as the desired result of the technical solution of this invention can be achieved, and this is not limited herein.

[0190] The specific embodiments described above do not constitute a limitation on the scope of protection of this invention. Those skilled in the art should understand that various modifications, combinations, sub-combinations, and substitutions can be made according to design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this invention should be included within the scope of protection of this invention.

Claims

1. A method for estimating the capacity of a power battery, characterized in that, The power battery charging includes a preparation stage, a charging stage, and an end stage. In the preparation stage, the BMS first controls the relay to open, and at the end of the preparation stage, the BMS controls the relay to close, and then the charging stage begins. In the final stage, the BMS controls the relay to disconnect and the disconnection time reaches a preset second duration; The power battery includes multiple battery modules, and the method includes: Obtain a first relationship curve between the recovery time and the recovery ratio of the battery module after the relay is disconnected, wherein the recovery ratio is the ratio of the module voltage recovery value at different recovery times to the total module voltage recovery value; Acquire first voltage recovery data for each battery module during the preparation phase. The first voltage recovery data includes the first module voltage, the second module voltage, and the first duration of the preparation phase at the beginning and end of the preparation phase. Acquire second voltage recovery data for each battery module in the end phase, the second voltage recovery data including the third module voltage, the fourth module voltage, and the second duration at the beginning and end of the end phase of the battery module; For each battery module, with the first relationship curve as a reference, the first open-circuit voltage before charging and the second open-circuit voltage after charging are calculated based on the first voltage recovery data and the second voltage recovery data, respectively. The first state of charge before charging and the second state of charge after charging of the battery module are determined based on the first open-circuit voltage and the second open-circuit voltage, respectively. The remaining capacity of the power battery is calculated based on the first state of charge and the second state of charge of all the battery modules. The step of calculating the remaining capacity of the power battery based on the first state of charge and the second state of charge of all the battery modules includes: Obtain the total charging capacity of the power battery during the charging phase; Calculate the mean of all first states of charge and the mean of all second states of charge to obtain the mean of the first state of charge and the mean of the second state of charge. The minimum remaining capacity of the power battery is calculated based on the maximum value of the second state of charge, the minimum value of the first state of charge, and the total charging capacity. The average remaining capacity of the power battery is calculated based on the first average state of charge, the second average state of charge, and the total charging capacity. The remaining capacity of the power battery is calculated based on the average remaining capacity, the minimum remaining capacity, and the preset allocation ratio.

2. The method of claim 1, wherein, The step of obtaining the first relationship curve between the recovery time and the recovery ratio of the battery module after the relay is disconnected includes: Historical voltage recovery data of a battery module sample with the same model as the battery module is obtained. The historical voltage recovery data is obtained under the condition that the resting time is greater than a preset recovery time. The historical voltage recovery data includes the recovery time and the voltage of the battery module sample corresponding to the recovery time. The maximum voltage and minimum voltage in the historical voltage recovery data are respectively used as the historical open-circuit voltage and the historical initial voltage; Calculate the difference between the historical open-circuit voltage and the historical initial voltage to obtain the total module voltage recovery value; Calculate the difference between the voltage of the battery module sample corresponding to each recovery time and the historical initial voltage to obtain the module voltage recovery value corresponding to the recovery time; Calculate the ratio of the module voltage recovery value corresponding to each recovery duration to the total module voltage recovery value to obtain the recovery ratio corresponding to each recovery duration; An initial relationship curve is generated based on the recovery duration and the corresponding recovery ratio; The initial relationship curve is fitted using a preset fitting polynomial to obtain the first relationship curve of the battery module.

3. The method of claim 1, wherein, For each battery module, using the first relationship curve as a reference, the calculation of the first open-circuit voltage before charging and the second open-circuit voltage after charging based on the first voltage recovery data and the second voltage recovery data includes: The recovery ratios corresponding to the first duration and the second duration are determined from the first relationship curve to obtain the first recovery ratio and the second recovery ratio. Calculate the first open-circuit voltage of the battery module before charging based on the first module voltage, the second module voltage, and the first recovery ratio; The second open-circuit voltage of the battery module after charging is calculated based on the voltage of the third module, the voltage of the fourth module, and the second recovery ratio.

4. The method of claim 1, wherein, The step of determining the first state of charge (SOC) before charging and the second SOC after charging of the battery module based on the first open-circuit voltage and the second open-circuit voltage, respectively, includes: Obtain the second relationship curve between the open-circuit voltage and the state of charge of the battery module; The states of charge corresponding to the first open-circuit voltage and the second open-circuit voltage are determined in the second relationship curve, respectively, to obtain the first state of charge of the battery module before charging and the second state of charge after charging.

5. The method of claim 1, wherein, After calculating the remaining capacity of the power battery based on the average remaining capacity, the minimum remaining capacity, and the preset allocation ratio, the method further includes: Calculate the capacity difference between the minimum remaining capacity and the average remaining capacity; When the capacity difference is greater than a preset capacity difference threshold, the voltage difference of the battery module in the power battery is determined to be abnormal.

6. The method according to any one of claims 1 to 5, wherein, After calculating the remaining capacity of the power battery based on the first state of charge and the second state of charge of all the battery modules, the method further includes: The remaining capacity of the power battery calculated at the moment is taken as the initial remaining capacity; Obtain first capacity data, which includes the current date D1, the initial remaining capacity, and the first cumulative charging capacity of the power battery after charging on date D1. Obtain second capacity data, which includes the date D2 of the last charge of the power battery, the historical remaining capacity and the second cumulative charge capacity stored after the charging ended on date D2; The reliability of the initial remaining capacity is determined based on the difference between the first capacity data and the second capacity data; The initial remaining capacity is updated based on the credibility and the historical remaining capacity.

7. The method of claim 6, wherein, The step of determining the reliability of the initial remaining capacity based on the difference between the first capacity data and the second capacity data includes: Calculate the difference between the initial remaining capacity and the historical remaining capacity to obtain a first difference value; Calculate the difference between the first cumulative charging capacity and the second cumulative charging capacity to obtain the second difference value; Calculate the difference in the number of days between date D1 and date D2; If the first difference value is less than the preset first difference threshold, then the confidence level of the initial remaining capacity is a preset fixed ratio value. If the first difference value is greater than or equal to a preset first threshold, the credibility of the initial remaining capacity is determined based on the second difference value or the number of days difference, and the credibility is positively correlated with the second difference value or the number of days difference.

8. An electronic device, comprising: The electronic device includes: At least one processor; and A memory communicatively connected to the at least one processor; wherein, The memory stores a computer program that can be executed by the at least one processor, the computer program being executed by the at least one processor to enable the at least one processor to perform the power battery capacity estimation method according to any one of claims 1-7.

9. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores computer instructions that cause a processor to execute the power battery capacity estimation method according to any one of claims 1-7.

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