Charging and discharging control method, controller, system, storage medium, and electrical device

Abstract

The present application discloses a charging and discharging control method, a controller, a system, a storage medium, and an electrical device. The method comprises: determining a starting point value of a next current reduction interval on the basis of characteristic inflection points of a plurality of battery cells in a present current reduction interval during battery charging, a charging current value in the present current reduction interval being less than a charging current value in a non-current reduction interval. Because the charging current value in the present current reduction interval is less than the charging current value in the non-current reduction interval, it can be ensured that the characteristic inflection point of the battery cell can be detected in the present current reduction interval, and the starting point value of the next current reduction interval is updated in real time on the basis of the characteristic inflection point, so that said method can be applied to batteries having different battery level deviations, and charging efficiency can be ensured.

Description

Charging and discharging control method, controller, system, storage medium and electrical equipment

[0001] The present application claims priority from the Chinese patent application No. 202411382798.0 filed on September 27, 2024, and entitled "Charging and discharging control method, controller, system, storage medium and electrical equipment", the content of which is incorporated herein by reference in its entirety. TECHNICAL FIELD

[0002] The present application relates to the technical field of battery management, in particular to a charging and discharging control method, a controller, a system, a storage medium and an electrical equipment. BACKGROUND

[0003] The existing battery includes a plurality of single cells arranged in series. In the use process of the battery, the most commonly used charging and discharging strategy is to stop charging when the highest single voltage in the battery exceeds the preset upper limit voltage, and to stop discharging when the lowest single voltage in the battery is lower than the preset lower limit voltage. Due to the different self-discharge rates of the plurality of single cells, the electric quantity of the plurality of single cells in the battery is different. The charging process is limited by the electric quantity of the single cell with the minimum electric quantity, which affects the capacity of the battery. An equalization control strategy needs to be used to control the charging and discharging of the plurality of single cells.

[0004] The existing equalization control strategy generally needs to detect the characteristic inflection points of all single cells in the battery, so as to control the charging and discharging of all single cells based on the detected characteristic inflection points. The process cannot take into account both the electric quantity equalization and the charging efficiency. SUMMARY

[0005] The present application provides a charging and discharging control method, a controller, a system, a storage medium and an electrical equipment to solve the problem that the existing battery charging and discharging control process cannot take into account both the electric quantity equalization and the charging efficiency.

[0006] In a first aspect, the present application discloses a charging and discharging control method, comprising:

[0007] determining a starting point value of a next current drop interval based on the characteristic inflection points of a plurality of single cells in a current current drop interval during battery charging;

[0008] wherein the charging current value in the current current drop interval is less than the charging current value in a non-current drop interval.

[0009] In a possible embodiment, the charging and discharging control method further comprises:

[0010] determining a voltage characteristic inflection point based on a voltage-quantity curve corresponding to each single cell;

[0011] Determine the characteristic inflection point of the single battery cell based on the voltage characteristic inflection point and the voltage capacity curve corresponding to the single battery cell.

[0012] In a possible implementation manner, the starting point value of the next current drop interval is determined based on the characteristic inflection points of the plurality of single battery cells in the current current drop interval during battery charging.

[0013] Determine at least one of the characteristic inflection point of the single battery cell with the highest voltage and the characteristic inflection point of the single battery cell with the lowest voltage based on the characteristic inflection points of the plurality of single battery cells.

[0014] Determine the starting point value of the next current drop interval based on at least one of the characteristic inflection point of the single battery cell with the highest voltage and the characteristic inflection point of the single battery cell with the lowest voltage and the current current drop interval.

[0015] The single battery cell with the highest voltage is the single battery cell with the highest voltage, and the single battery cell with the lowest voltage is the single battery cell with the lowest voltage.

[0016] In a possible implementation manner, the starting point value of the next current drop interval is determined based on the characteristic inflection points of the plurality of single battery cells in the current current drop interval during battery charging.

[0017] If the characteristic inflection points of the plurality of single battery cells include the characteristic inflection point of the single battery cell with the highest voltage and the characteristic inflection point of the single battery cell with the lowest voltage, the starting point value of the next current drop interval is the initial starting point value or the starting point value of the current current drop interval, wherein the single battery cell with the highest voltage is the single battery cell with the highest voltage, and the single battery cell with the lowest voltage is the single battery cell with the lowest voltage.

[0018] In a possible implementation manner, the starting point value of the next current drop interval is determined based on the characteristic inflection points of the plurality of single battery cells in the current current drop interval during battery charging.

[0019] If the characteristic inflection points of the plurality of single battery cells include the characteristic inflection point of the single battery cell with the highest voltage and do not include the characteristic inflection point of the single battery cell with the lowest voltage, the starting point value of the next current drop interval is greater than the starting point value of the current current drop interval, wherein the single battery cell with the highest voltage is the single battery cell with the highest voltage, and the single battery cell with the lowest voltage is the single battery cell with the lowest voltage.

[0020] In a possible implementation manner, the starting point value of the next current drop interval is determined based on the characteristic inflection points of the plurality of single battery cells in the current current drop interval during battery charging.

[0021] If the characteristic inflection points of the plurality of single battery cells include the characteristic inflection point of the single battery cell with the highest voltage and do not include the characteristic inflection point of the single battery cell with the lowest voltage, the starting point value of the next current drop interval is the sum of the starting point value of the current current drop interval and the first change amount.

[0022] In a possible implementation, the first change amount is the smaller one of the second change amount and the measured change amount.

[0023] The measured change amount is an equalization change amount of the battery in this time of equalization control.

[0024] In a possible implementation, the determination of the start value of the next current drop interval based on the feature inflection points of the plurality of single battery cells in the current drop interval when the battery is charging comprises:

[0025] If the feature inflection points of the plurality of single battery cells include the feature inflection point of the single battery cell with the lowest voltage and do not include the feature inflection point of the single battery cell with the highest voltage, the start value of the next current drop interval is the start value of the current drop interval, where the single battery cell with the highest voltage is the single battery cell with the highest voltage, and the single battery cell with the lowest voltage is the single battery cell with the lowest voltage.

[0026] In a possible implementation, the determination of the start value of the next current drop interval based on the feature inflection points of the plurality of single battery cells in the current drop interval when the battery is charging comprises:

[0027] If the feature inflection points of the plurality of single battery cells do not include the feature inflection point of the single battery cell with the highest voltage and the feature inflection point of the single battery cell with the lowest voltage, the start value of the next current drop interval is smaller than the start value of the current drop interval, where the single battery cell with the highest voltage is the single battery cell with the highest voltage, and the single battery cell with the lowest voltage is the single battery cell with the lowest voltage.

[0028] In a possible implementation, the determination of the start value of the next current drop interval based on the feature inflection points of the plurality of single battery cells in the current drop interval when the battery is charging comprises:

[0029] If the feature inflection points of the plurality of single battery cells do not include the feature inflection point of the single battery cell with the highest voltage and the feature inflection point of the single battery cell with the lowest voltage, the start value of the next current drop interval is the difference between the start value of the current drop interval and the second change amount.

[0030] In a possible implementation, the charge-discharge control method further comprises:

[0031] performing equalization control on the battery.

[0032] In a possible implementation, the equalization control on the battery comprises:

[0033] If the feature inflection points of the plurality of single battery cells include the feature inflection point of the single battery cell with the highest voltage and the feature inflection point of the single battery cell with the lowest voltage, performing equalization control on all single battery cells of the battery.

[0034] In a possible implementation mode, after the balancing control on all the single battery cells of the battery, the charge and discharge control method comprises:

[0035] updating the current state of the battery to an ideal balancing state, and recording the current time as a balancing time of the ideal balancing state.

[0036] In a possible implementation mode, the balancing control on the battery comprises:

[0037] If the characteristic inflection points of the plurality of single battery cells include the characteristic inflection point of the highest voltage cell and do not include the characteristic inflection point of the lowest voltage cell, the highest voltage cell is controlled to be discharged based on a first balancing amount.

[0038] In a possible implementation mode, the charge and discharge control method further comprises:

[0039] Each first single battery cell is controlled to be discharged based on a second balancing amount corresponding to the first single battery cell, wherein the first single battery cell is a single battery cell other than the highest voltage cell and having the characteristic inflection point within the current discharge reduction interval, and the second balancing amount is less than the first balancing amount.

[0040] In a possible implementation mode, the second balancing amount is a difference between the first balancing amount and a third change amount.

[0041] The third change amount is determined based on the characteristic inflection point of the highest voltage cell and the characteristic inflection point of the first single battery cell.

[0042] In a possible implementation mode, the balancing control on the battery comprises:

[0043] If the characteristic inflection points of the plurality of single battery cells include the characteristic inflection point of the lowest voltage cell and do not include the characteristic inflection point of the highest voltage cell, a second single battery cell is controlled to be discharged based on a first balancing amount, and the second single battery cell is a single battery cell without the characteristic inflection point in the current charging process.

[0044] In a possible implementation mode, the balancing control on the battery comprises:

[0045] If the characteristic inflection points of the plurality of single battery cells include the characteristic inflection point of the lowest voltage cell and do not include the characteristic inflection point of the highest voltage cell, each third single battery cell is controlled to be discharged based on a third balancing amount corresponding to the third single battery cell, and the third single battery cell is a single battery cell other than the lowest voltage cell and having the characteristic inflection point within the current discharge reduction interval, and the third balancing amount is less than or equal to the first balancing amount.

[0046] In a possible implementation manner, the third equalization amount is determined based on the characteristic inflection point of the third single battery cell and the characteristic inflection point of the lowest voltage battery cell.

[0047] In a possible implementation manner, the charge and discharge control method further includes:

[0048] When the cell SOC of the highest voltage battery cell is greater than a preset SOC threshold, the start value of the next current drop interval is determined as the initial start value.

[0049] In a possible implementation manner, the charge and discharge control method further includes:

[0050] When the characteristic inflection point of the single battery cell is not included in the current current drop interval, the start value of the next current drop interval is determined based on the maximum voltage difference of the plurality of single battery cells in the current current drop interval.

[0051] In a possible implementation manner, the start value of the next current drop interval is determined based on the maximum voltage difference of the plurality of single battery cells in the current current drop interval, including:

[0052] When the plurality of maximum voltage differences satisfy a preset voltage difference condition, the start value of the next current drop interval is determined to be less than the start value of the current current drop interval.

[0053] In a possible implementation manner, the start value of the next current drop interval is determined based on the maximum voltage difference of the plurality of single battery cells in the current current drop interval, including:

[0054] When the plurality of maximum voltage differences satisfy a preset voltage difference condition, the start value of the next current drop interval is determined to be the difference between the start value of the current current drop interval and a second change amount.

[0055] In a possible implementation manner, the start value of the next current drop interval is determined based on the maximum voltage difference of the plurality of single battery cells in the current current drop interval, including:

[0056] When the plurality of maximum voltage differences do not satisfy the preset voltage difference condition, the start value of the next current drop interval is determined to be greater than the start value of the current current drop interval.

[0057] In a possible implementation manner, the start value of the next current drop interval is determined based on the maximum voltage difference of the plurality of single battery cells in the current current drop interval, including:

[0058] When the plurality of maximum voltage differences do not satisfy the preset voltage difference condition, the start value of the next current drop interval is determined to be the sum of the start value of the current current drop interval and a second change amount.

[0059] In a possible implementation, the preset pressure difference condition is that the mean value of the cell pressure difference is greater than a preset pressure difference threshold.

[0060] The mean value of the cell pressure difference is a mean value of maximum voltage differences of the plurality of single cells in the current current reduction interval.

[0061] In a possible implementation, the method further includes:

[0062] charging the battery based on a first charging current when the first measured SOC of the battery is in the current current reduction interval.

[0063] In a possible implementation, the method further includes:

[0064] charging the battery based on a second charging current when the first measured SOC of the battery is not in the current current reduction interval, the second charging current being greater than the first charging current.

[0065] In a possible implementation, the current current reduction interval includes a start value and an end value, and a difference between the start value and the end value is equal in any two charging processes.

[0066] In a possible implementation, before charging the battery based on the first charging current when the first measured SOC of the battery is in the current current reduction interval, the method further includes:

[0067] charging the battery based on a second charging current, the second charging current being greater than the first charging current;

[0068] determining the current current reduction interval based on a second measured SOC.

[0069] In a possible implementation, the method further includes:

[0070] charging the battery based on a second charging current, and obtaining a second measured SOC of the battery when the current charging capacity reaches a preset charging capacity.

[0071] In a possible implementation, the determining the current current reduction interval based on the second measured SOC includes:

[0072] determining a start value of the current current reduction interval as a larger value of the second measured SOC and a start value of a preset current reduction interval;

[0073] determining an end value of the current current reduction interval as a sum of the start value of the current current reduction interval and a preset step length.

[0074] In a possible implementation, the charge and discharge control method further includes:

[0075] obtaining first battery data of the battery, and determining a current discharge reduction interval when the first battery data meets a discharge reduction balancing condition.

[0076] In a possible implementation, the first battery data includes a current charging mode and a current interval duration, and the current interval duration is a difference between a current time and a balancing time of a last ideal balancing state.

[0077] The discharge reduction balancing condition includes that the current charging mode is a direct current charging mode, and the current interval duration is greater than a preset interval duration.

[0078] In a possible implementation, the first battery data includes a current charging mode and a current interval duration, and the current interval duration is a difference between a current time and a balancing time of a last ideal balancing state.

[0079] After the first battery data corresponding to the battery is obtained, the charge and discharge control method further includes:

[0080] When the current charging mode is a direct current charging mode and the current interval duration is not greater than a preset interval duration, the battery is charged based on a second charging current, and the second charging current is greater than the first charging current.

[0081] In a possible implementation, the first battery data includes a current charging mode.

[0082] After the first battery data corresponding to the battery is obtained, the charge and discharge control method further includes:

[0083] When the current charging mode is an alternating current charging mode, the battery is charged based on a second charging current, and all single battery cells of the battery are subjected to balancing control, and the second charging current is greater than the first charging current.

[0084] In a second aspect, a controller is disclosed, including a memory, a processor, and a computer program stored in the memory and executable on the processor, and the processor implements the charge and discharge control method when executing the computer program.

[0085] In a third aspect, a charge and discharge control system is disclosed, including a battery and the above controller, and the controller is connected to the battery.

[0086] In a fourth aspect, a computer readable storage medium is disclosed, and the computer readable storage medium stores a computer program, and the computer program implements the charge and discharge control method when executed by a processor.

[0087] In a fifth aspect, the present application discloses a power utilization device, which comprises the controller, or the charge-discharge control system, or the computer readable storage medium.

[0088] In combination with the above technical solution, in the charge-discharge control method, the controller, the system, the storage medium and the power utilization device provided by the present application, since the charging current value in the current current-drop interval is smaller than the charging current value in the non-current-drop interval, the characteristic inflection points of the plurality of single battery cells can be detected when the battery is charged in the current current-drop interval, so as to guarantee the feasibility of the scheme, and the charging efficiency can be guaranteed when the battery is charged in the non-current-drop interval; and based on the characteristic inflection points of the plurality of single battery cells in the current current-drop interval, the starting point value of the next current-drop interval is determined, so as to achieve the equalization control purpose through multiple charging, and the characteristic inflection points of all single battery cells do not need to be detected at each time of charging, the detection time of the characteristic inflection points can be saved, the battery does not need to be charged in a large range of current-drop interval, and thus the charging efficiency of the battery is guaranteed. BRIEF DESCRIPTION OF DRAWINGS

[0089] FIG. 1 is a first flowchart of a charge-discharge control method in an embodiment of the present application;

[0090] FIG. 2 is a second flowchart of a charge-discharge control method in an embodiment of the present application;

[0091] FIG. 3 is a third flowchart of a charge-discharge control method in an embodiment of the present application;

[0092] FIG. 4 is a fourth flowchart of a charge-discharge control method in an embodiment of the present application. DETAILED DESCRIPTION

[0093] The technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only some of the embodiments of the present application, but not all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0094] In the existing equalization control strategy, the characteristic inflection point SOC of the single battery cell needs to be detected, and the characteristic inflection point SOC can be detected in the small-current charging process, but cannot be detected in the large-current charging process. Therefore, the current needs to be dropped in a specific SOC interval. This method needs to detect the characteristic inflection point SOC of all single battery cells in one current-drop charging process, so that it is only suitable for the battery with small deviation of electric quantity, but not suitable for the battery with large deviation of electric quantity, and the specific SOC interval range is large, which affects the charging efficiency of the battery.

[0095] The embodiment of the present application provides a charge and discharge control method, which can be applied to a controller connected with a battery. The controller can be a BMS or other controllers, such as a vehicle controller arranged on a vehicle. As shown in FIG. 1, the charge and discharge control method comprises the following steps:

[0096] S1: determining feature inflection points of a plurality of single battery cells;

[0097] S2: determining a start point value of a next current reduction interval based on the feature inflection points of the plurality of single battery cells in a current current reduction interval during battery charging;

[0098] Wherein, the charging current value in the current current reduction interval is less than the charging current value in the non-current reduction interval.

[0099] Wherein, the battery refers to a battery for the present charge and discharge control, and the battery comprises a plurality of single battery cells arranged in series. The current current reduction interval refers to a current reduction interval corresponding to the present charging. As an example, the current current reduction interval can be a pre-set current reduction interval or a dynamically determined current reduction interval according to measured data. The next current reduction interval refers to a current reduction interval for the next charging. The current reduction interval refers to an SOC interval or a capacity interval in which the charging current needs to be reduced.

[0100] Wherein, the charging current value in the current current reduction interval refers to the charging current determined based on a current reduction charging strategy in the current current reduction interval, which can be set as 0.2C or other smaller charging current (referred to as small current) that can ensure that the feature inflection points of all single battery cells can be detected. The current reduction charging strategy refers to a strategy for reducing the charging current, which is different from a normal charging strategy and is used to ensure that the feature inflection points in the battery charging process can be detected. The charging current value in the non-current reduction interval refers to the charging current value determined based on the normal charging strategy outside the current current reduction interval, which can be set as 0.5C or a larger charging current (referred to as large current) determined according to the charging demand. The normal charging strategy refers to a strategy for normal charging according to actual demand. Generally, the current reduction charging strategy specifically refers to charging the battery based on the smaller charging current in the current current reduction interval under specific conditions, so that the feature inflection points of the plurality of single battery cells of the battery in the charging process can be detected. In an embodiment, the threshold of the large current and the small current is generally in the range of 0.2C-0.3C, that is, when the current is greater than 0.3C, there is no feature inflection point. However, in some embodiments, the threshold of the large current and the small current is greater than 0.3C, and therefore the specific value needs to be adjusted according to the voltage characteristic curve of the corresponding battery, that is, by adjusting the charging current of the battery and performing differential processing on the voltage characteristic curve of the battery to determine whether there is an inflection point to determine the threshold of the large current and the small current.

[0101] As an example, the controller can acquire the first measured data (e.g. measured SOC or measured capacity) corresponding to the battery during charging of the battery, compare the first measured data with the current drop interval; when the first measured data of the battery is within the current drop interval, charge the battery based on the charging current value within the current drop interval. Since the charging current value within the current drop interval is small, the characteristic inflection points of the plurality of single battery cells in the battery can be detected, so as to subsequently balance control the battery based on the detected characteristic inflection points, so as to protect the capacity balance of the plurality of single battery cells in the battery.

[0102] As an example, the controller needs to detect the cell characteristics (such as cell voltage or other characteristics) corresponding to the plurality of single battery cells and also acquire the cell SOC or cell capacity during charging of the battery based on the smaller charging current value within the current drop interval. Based on the cell characteristics and the cell SOC, a cell characteristic curve is constructed, or based on the cell characteristics and the cell capacity, a cell characteristic curve is constructed. Then, the cell characteristic curve is differentiated, the ordinate inflection point in the cell characteristic curve is determined, the characteristic inflection points corresponding to the plurality of single battery cells are determined, and the inflection point data corresponding to the characteristic inflection points is determined. The inflection point data contains the cell characteristics corresponding to the ordinate and the cell SOC or cell capacity corresponding to the abscissa. In this example, the controller analyzes and determines the characteristic inflection points corresponding to the plurality of single battery cells based on the detected cell characteristics and the cell SOC / cell capacity and other measured data corresponding to the plurality of single battery cells, and then determines which single battery cells corresponding to the characteristic inflection points fall within the current drop interval and which single battery cells corresponding to the characteristic inflection points do not fall within the current drop interval, so as to determine the starting value of the next drop interval and perform different balancing control according to different situations.

[0103] As an example, after the controller detects the characteristic inflection points of the plurality of single battery cells within the current drop interval, the controller can determine the capacity deviation of the plurality of single battery cells based on the characteristic inflection points of the plurality of single battery cells, and then update the starting value of the next drop interval based on the capacity deviation of the plurality of single battery cells, so as to determine the next drop interval as the new current drop interval during the next charging of the battery, and perform drop charging based on the current drop interval. Understandably, the starting value of the next drop interval is updated based on the characteristic inflection points of the plurality of single battery cells within the current drop interval, so that the battery reaches a more balanced state after multiple charging, thereby achieving the purpose of balancing control.

[0104] In the embodiment, since the charging current value in the current current reduction interval is less than the charging current value in the non-current reduction interval, the characteristic inflection points of the plurality of single battery cells can be detected when the battery is charged in the current current reduction interval, the feasibility of the scheme is ensured, and the charging efficiency can be ensured when the battery is charged in the non-current reduction interval; based on the characteristic inflection points of the plurality of single battery cells in the current current reduction interval, the start point value of the next current reduction interval is determined, so that the equalization control purpose is achieved through multiple charging, and the characteristic inflection points of all single battery cells do not need to be detected each time, the detection time of the characteristic inflection points can be saved, the battery does not need to be charged in a large range of current reduction interval, and the charging efficiency of the battery is ensured.

[0105] In an embodiment, as shown in FIG. 2, in step S1, the charging and discharging control method further includes:

[0106] S11: determining a voltage characteristic inflection point based on the voltage and power curve corresponding to each single battery cell;

[0107] S12: determining the characteristic inflection point of the single battery cell based on the voltage characteristic inflection point and the voltage and power curve corresponding to the single battery cell.

[0108] The voltage and power curve is a curve constructed based on the battery cell voltage and the battery cell power, which is one of the battery cell characteristic curves in the above embodiment, and is used to reflect the relationship between the battery cell voltage, which is a battery cell characteristic, and the battery cell power. The battery cell voltage is the voltage of the single battery cell detected in real time. The battery cell power is the power information of the single battery cell detected in real time, which can be the battery cell SOC or the battery cell capacity.

[0109] As an example, when the controller charges the battery based on the charging current value in the current current reduction interval, the battery needs to be detected to determine the battery cell voltage and the battery cell power of the plurality of single battery cells in the battery; then, the voltage and power curve corresponding to the battery cell voltage and the battery cell power is determined, which can be constructed with the battery cell power as the horizontal coordinate and the battery cell voltage as the vertical coordinate. Then, the controller analyzes and processes the voltage and power curve corresponding to each single battery cell, for example, differentiates the voltage and power curve corresponding to each single battery cell to determine the voltage characteristic inflection point corresponding to each single battery cell. Finally, the controller determines the characteristic inflection point of the single battery cell based on the voltage characteristic inflection point and the voltage and power curve corresponding to the single battery cell, and then determines the inflection point data corresponding to the characteristic inflection point, wherein the inflection point data includes the battery cell power corresponding to the horizontal coordinate and the battery cell voltage corresponding to the vertical coordinate, so as to perform subsequent control based on the determined characteristic inflection point and the inflection point data.

[0110] In an embodiment, as shown in FIG. 3, in step S2, the start point value of the next current reduction interval is determined based on the characteristic inflection points of the plurality of single battery cells in the current current reduction interval when the battery is charged, including:

[0111] S21: determining at least one of the characteristic inflection point of the highest voltage cell and the characteristic inflection point of the lowest voltage cell based on the characteristic inflection points of the plurality of single cells;

[0112] S22: determining the start value of the next current drop interval based on at least one of the characteristic inflection point of the highest voltage cell and the characteristic inflection point of the lowest voltage cell and the current current drop interval;

[0113] wherein the highest voltage cell is the single cell with the highest cell voltage, and the lowest voltage cell is the single cell with the lowest cell voltage.

[0114] wherein the highest voltage cell is the single cell with the highest cell voltage, which can be represented by Vmax, and the lowest voltage cell is the single cell with the lowest cell voltage, which can be represented by Vmin.

[0115] As an example, after determining the characteristic inflection points of the plurality of single cells, the controller further compares the cell voltages of all single cells to determine the highest voltage cell Vmax and the lowest voltage cell Vmin, and then determines at least one of the characteristic inflection point of the highest voltage cell Vmax and the characteristic inflection point of the lowest voltage cell Vmin, i.e., either the characteristic inflection point of the highest voltage cell Vmax or only the characteristic inflection point of the lowest voltage cell Vmin or both. Understandably, when determining at least one of the characteristic inflection point of the highest voltage cell Vmax and the characteristic inflection point of the lowest voltage cell Vmin, the inflection point data corresponding to these characteristic inflection points can be determined, i.e., the cell voltage and the cell capacity (such as cell SOC or cell capacity) corresponding to the characteristic inflection points.

[0116] As an example, the controller can evaluate whether at least one of the characteristic inflection point of the highest voltage cell and the characteristic inflection point of the lowest voltage cell falls into the current current drop interval based on at least one of the characteristic inflection point of the highest voltage cell and the characteristic inflection point of the lowest voltage cell and the current current drop interval, so as to determine the start value of the next current drop interval according to different strategies according to the evaluation result, so as to dynamically update the start value of the next current drop interval according to the actual situation of the battery. For example, when the inflection point data corresponding to the characteristic inflection point includes the cell capacity and the cell SOC, and the current current drop interval is the SOC interval, different strategies can be adopted to determine the start value of the next current drop interval according to the evaluation result of whether the cell SOC of the characteristic inflection point falls into the SOC interval.

[0117] In an embodiment, as shown in FIG. 4, the start value of the next current drop interval is determined based on the characteristic inflection points of the plurality of single cells in the current current drop interval when the battery is charging, comprising:

[0118] If the characteristic inflection points of the plurality of single battery cells include the characteristic inflection point of the highest voltage battery cell and the characteristic inflection point of the lowest voltage battery cell, the starting point value of the next current drop interval is the initial starting point value or the starting point value of the current current drop interval, wherein the highest voltage battery cell is the single battery cell with the highest battery cell voltage, and the lowest voltage battery cell is the single battery cell with the lowest battery cell voltage.

[0119] wherein the initial starting point value is a pre-set starting point value for implementing the current drop control, for example, when the current drop interval is an SOC interval, the initial starting point value thereof can be set to 40%; correspondingly, when the current drop interval is a capacity interval, the initial starting point value thereof can be determined according to the total capacity of the battery, and can be the total capacity * 40% or other numerical value, and the following embodiments are described by taking the SOC interval as an example.

[0120] As an example, the characteristic inflection points of the plurality of single battery cells in the current current drop interval include the characteristic inflection point of the highest voltage battery cell and the characteristic inflection point of the lowest voltage battery cell, i.e., the characteristic inflection point of the highest voltage battery cell Vmax and the characteristic inflection point of the lowest voltage battery cell Vmin are both in the current current drop interval, it can be determined that the power of all single battery cells of the battery is relatively balanced, i.e., the power deviation of all single battery cells is small, at this time, it can be determined that the starting point value of the next current drop interval is the initial starting point value, i.e., the starting point value of the next current drop interval SOC_Ah0 = initial starting point value = 40%, or it can be determined that the starting point value of the next current drop interval is the starting point value of the current current drop interval, i.e., SOC_Ah0' = SOC_Ah0, so that when the first measured data of the battery reaches 40% during the next charging, the battery is charged based on the charging current value in the current current drop interval.

[0121] In an embodiment, as shown in FIG. 4, based on the characteristic inflection points of the plurality of single battery cells in the current current drop interval when the battery is being charged, the starting point value of the next current drop interval is determined, comprising:

[0122] If the characteristic inflection points of the plurality of single battery cells include the characteristic inflection point of the highest voltage battery cell and do not include the characteristic inflection point of the lowest voltage battery cell, the starting point value of the next current drop interval is greater than the starting point value of the current current drop interval, wherein the highest voltage battery cell is the single battery cell with the highest battery cell voltage, and the lowest voltage battery cell is the single battery cell with the lowest battery cell voltage.

[0123] As an example, the characteristic inflection points of the plurality of single battery cells in the current current drop interval include the characteristic inflection point of the highest voltage battery cell and do not include the characteristic inflection point of the lowest voltage battery cell, i.e., the characteristic inflection point of the highest voltage battery cell Vmax is in the current current drop interval, and the characteristic inflection point of the lowest voltage battery cell Vmin is not in the current current drop interval, the starting point value of the next current drop interval needs to be increased, so that the starting point value of the next current drop interval is greater than the starting point value of the current current drop interval, so that the battery is charged by current drop when the first measured data of the battery reaches a larger starting point value during the next charging.

[0124] In an embodiment, as shown in FIG. 4, the starting point value of the next flow-down interval is determined based on the characteristic inflection points of the plurality of single battery cells in the current flow-down interval, including:

[0125] If the characteristic inflection points of the plurality of single battery cells include the characteristic inflection point of the highest voltage cell and do not include the characteristic inflection point of the lowest voltage cell, the starting point value of the next flow-down interval is the sum of the starting point value of the current flow-down interval and a first change amount.

[0126] The first change amount is a change amount for increasing the starting point value, and the first change amount is a positive number. As an example, when the flow-down interval is an SOC interval, the first change amount is a first SOC change amount, which can be represented by SOC_Ah1. The first change amount can be a pre-set change amount, for example, 3%, or a dynamically determined change amount according to actual conditions. The following embodiments take the SOC interval as an example for description.

[0127] As an example, when the characteristic inflection points of the plurality of single battery cells in the current flow-down interval include the characteristic inflection point of the highest voltage cell and do not include the characteristic inflection point of the lowest voltage cell, i.e., the characteristic inflection point of the highest voltage cell Vmax is in the current flow-down interval, and the characteristic inflection point of the lowest voltage cell Vmin is not in the current flow-down interval, the starting point value of the next flow-down interval needs to be increased. Specifically, the sum of the starting point value of the current flow-down interval and the first change amount is determined as the starting point value of the next flow-down interval, i.e., SOC_Ah0' = SOC_Ah0 + SOC_Ah1, so that when the first measured data of the battery reaches the SOC_Ah0' of the next flow-down interval during the next charging, the battery is charged based on the charging current value in the current flow-down interval.

[0128] Understandably, when the flow-down interval is a capacity interval, the first change amount is a first capacity change amount, and the process of updating the next flow-down interval is similar to the SOC interval updating process. To avoid repetition, details are not described here.

[0129] In an embodiment, as shown in FIG. 4, the first change amount is the smaller value of a second change amount and a measured change amount;

[0130] The measured change amount is the equalization change amount of the current equalization control of the battery.

[0131] The second variation is a pre-set variation, and the second variation is a positive number. As an example, when the flow reduction interval is the SOC interval, the second variation is the second SOC variation, which can be represented by SOC_Ah2, for example, and can be set to 3% or other values. The measured variation is the equalization variation of the battery in this equalization control, that is, the equalization variation between the equalization start time and the equalization end time, which can be determined according to the relationship between the batteries. In addition, in an example, the measured variation can be determined according to the characteristic inflection point of the plurality of battery cells. Specifically, the plurality of battery cells includes a reference battery cell, and therefore the measured variation can be determined according to the difference between the inflection point of the reference battery cell and the inflection point between the other battery cells.

[0132] As an example, when the flow reduction interval is the SOC interval, the controller needs to control at least one single battery cell in the battery to perform equalization control when the characteristic inflection point of the highest voltage battery Vmax is within the current flow reduction interval, and the characteristic inflection point of the lowest voltage battery Vmin is not within the current flow reduction interval. The measured SOC of each battery at the equalization start time is recorded; when at least one single battery cell in the battery stops performing equalization control, the battery is recharged, and the measured SOC corresponding to the recharging time (i.e., the equalization end time) of the battery needs to be recorded. The difference between the measured SOC at the equalization start time and the measured SOC at the equalization end time is calculated, which is determined as the measured variation of the battery. That is, the measured variation is the actual SOC discharged by the battery during the equalization control process, which can be applied to the special situation that the equalization control may be temporarily interrupted in actual situations. Then, the controller compares the second variation and the measured variation, and determines the smaller value of the two as the first variation. The sum of the start value of the current flow reduction interval and the first variation is determined as the start value of the next flow reduction interval.

[0133] For example, when the second variation is 3% and the measured variation is Qbal, the start value of the next flow reduction interval is SOC_Ah0' = SOC_Ah0 + SOC_Ah1 = SOC_Ah0 + min(3%, Qbal).

[0134] Understandably, when the flow reduction interval is the capacity interval, the second variation is the second capacity variation, which updates the next flow reduction interval, and the process is similar to the SOC interval update process. To avoid repetition, this will not be described here.

[0135] In an embodiment, as shown in FIG. 4, the start value of the next flow reduction interval is determined based on the characteristic inflection points of the plurality of single battery cells within the current flow reduction interval when the battery is charging, including:

[0136] If the characteristic inflection points of the plurality of single battery cells include the characteristic inflection point of the lowest voltage battery cell and do not include the characteristic inflection point of the highest voltage battery cell, the starting point value of the next discharge interval is the starting point value of the current discharge interval, wherein the highest voltage battery cell is the single battery cell with the highest battery voltage and the lowest voltage battery cell is the single battery cell with the lowest battery voltage.

[0137] As an example, if the characteristic inflection points of the plurality of single battery cells in the current discharge interval include the characteristic inflection point of the lowest voltage battery cell and do not include the characteristic inflection point of the highest voltage battery cell, i.e., the characteristic inflection point of the lowest voltage battery cell is in the current discharge interval and the characteristic inflection point of the highest voltage battery cell is not in the current discharge interval, the starting point value is maintained, i.e., the starting point value of the next discharge interval SOC_Ah0' is determined as the starting point value of the current discharge interval SOC_Ah0, i.e., SOC_Ah0' = SOC_Ah0, so that during the next charging, the battery is charged based on the charging current value in the current discharge interval when the first measured data of the battery reaches the SOC_Ah0 of the next discharge interval.

[0138] In an embodiment, as shown in FIG. 4, the starting point value of the next discharge interval is determined based on the characteristic inflection points of the plurality of single battery cells in the current discharge interval when the battery is being charged, including:

[0139] If the characteristic inflection points of the plurality of single battery cells do not include the characteristic inflection point of the highest voltage battery cell and the characteristic inflection point of the lowest voltage battery cell, the starting point value of the next discharge interval is less than the starting point value of the current discharge interval, wherein the highest voltage battery cell is the single battery cell with the highest battery voltage and the lowest voltage battery cell is the single battery cell with the lowest battery voltage.

[0140] As an example, if the characteristic inflection points of the plurality of single battery cells in the current discharge interval do not include the characteristic inflection point of the highest voltage battery cell and the characteristic inflection point of the lowest voltage battery cell, i.e., the characteristic inflection point of the highest voltage battery cell and the characteristic inflection point of the lowest voltage battery cell are both not in the current discharge interval, but the characteristic inflection points of the single battery cells other than the highest voltage battery cell and the lowest voltage battery cell are in the current discharge interval, it indicates that the power deviation of the highest voltage battery cell and the lowest voltage battery cell is extremely large and the plurality of single battery cells cannot be quickly and effectively balanced, at this time, the starting point value of the next discharge interval needs to be reduced, so that the starting point value of the next discharge interval is less than the starting point value of the current discharge interval, so that during the next charging, the highest voltage battery cell is tracked based on the starting point value of the next discharge interval to effectively balance the single battery cell with higher power.

[0141] In an embodiment, as shown in FIG. 4, the starting point value of the next discharge interval is determined based on the characteristic inflection points of the plurality of single battery cells in the current discharge interval when the battery is being charged, including:

[0142] If the characteristic turning points of the plurality of single battery cells do not include the characteristic turning point of the single battery cell with the highest voltage and the characteristic turning point of the single battery cell with the lowest voltage, the start value of the next current reduction interval is the difference between the start value of the current current reduction interval and the second variation.

[0143] The second variation is a pre-set variation. As an example, when the current reduction interval is an SOC interval, the second variation is a second SOC variation, which can be represented by SOC_Ah2, and can be set to 3% or other values.

[0144] As an example, when the characteristic turning points of the plurality of single battery cells in the current current reduction interval do not include the characteristic turning point of the single battery cell with the highest voltage and the characteristic turning point of the single battery cell with the lowest voltage, i.e., the characteristic turning point of the single battery cell with the highest voltage and the characteristic turning point of the single battery cell with the lowest voltage are both not in the current current reduction interval, but the characteristic turning points of the single battery cells other than the single battery cell with the highest voltage and the single battery cell with the lowest voltage are in the current current reduction interval, it indicates that the power deviation of the single battery cell with the highest voltage and the single battery cell with the lowest voltage is extremely large, and the plurality of single battery cells cannot be quickly and effectively balanced. At this time, the difference between the start value of the current current reduction interval and the second variation can be determined as the start value of the next current reduction interval. For example, when the start value is SOC_Ah0 and the second variation is 3%, the updated SOC_Ah0' = SOC_Ah0 - SOC_Ah2 = SOC_Ah0 - 3%, so that in the next charging, the single battery cell with the highest voltage is tracked based on the start value of the next current reduction interval, and effective balancing control is achieved on the single battery cell with higher power.

[0145] Understandably, when the current reduction interval is a capacity interval, the second variation is a second capacity variation, and the process of updating the next current reduction interval is similar to the SOC interval updating process. To avoid repetition, details are not repeated here.

[0146] In an embodiment, the charging and discharging control method further comprises: performing balancing control on the battery.

[0147] As an example, the controller determines the deviation of the electric quantity (cell capacity or cell SOC) of the plurality of single battery cells according to the characteristic inflection points of the plurality of single battery cells upon determining the characteristic inflection points of the plurality of single battery cells, and then determines different equalization working conditions, adopts the characteristic inflection point equalization strategy corresponding to the different equalization working conditions to perform equalization control on the plurality of single battery cells, so as to ensure the equalization of the electric quantity of the plurality of single battery cells of the battery. The characteristic inflection point equalization strategy refers to an equalization control strategy based on the detected characteristic inflection points. The equalization control here can be understood as a control process of controlling the single battery cell to bleed off, so as to equalize the electric quantity among the plurality of single battery cells. For example, a bleed-off circuit and a bleed-off switch connected to each single battery cell are arranged at both ends of each single battery cell of the battery. When the electric quantity of the plurality of single battery cells is not equalized, the bleed-off switch corresponding to the single battery cell with higher electric quantity is turned on, so that the electric quantity of the single battery cell with higher electric quantity is discharged through the bleed-off circuit, and the single battery cell with lower electric quantity is equalized.

[0148] In the present example, the battery is charged based on the charging current value in the current current reduction interval within the current current reduction interval to ensure that the characteristic inflection points of all single battery cells can be detected during the charging of the battery, so as to effectively avoid the situation that the characteristic inflection points of part of the single battery cells cannot be detected due to the large current charging of the battery; and then the equalization control is performed on the battery by adopting the characteristic inflection point equalization strategy corresponding to the different equalization working conditions determined by at least one of the characteristic inflection point of the single battery cell with the highest voltage and the characteristic inflection point of the single battery cell with the lowest voltage and the current current reduction interval, so as to equalize the electric quantity of the plurality of single battery cells of the battery.

[0149] In an embodiment, as shown in FIG. 4, the equalization control is performed on the battery, including:

[0150] If the characteristic inflection points of the plurality of single battery cells include the characteristic inflection point of the single battery cell with the highest voltage and the characteristic inflection point of the single battery cell with the lowest voltage, the equalization control is performed on all single battery cells of the battery.

[0151] As an example, the feature inflection points of the plurality of single battery cells in the current discharge interval include the feature inflection point of the highest voltage battery cell and the feature inflection point of the lowest voltage battery cell, i.e., the feature inflection point of the highest voltage battery cell Vmax and the feature inflection point of the lowest voltage battery cell Vmin are both in the current discharge interval, so the capacity of all single battery cells of the battery (cell capacity or cell SOC) can be determined through the feature inflection points, and then the capacity difference of all single battery cells can be determined, at this time, all single battery cells in the battery can be controlled for equalization, i.e., the bleed switches of all single battery cells are controlled to be turned on, so that the bleed circuits corresponding to all single battery cells are discharged to balance the capacity of all single battery cells, so that the capacity of all single battery cells reaches the capacity of the reference battery cell, so that all single battery cells reach a more ideal equalization state. In the above example, during the equalization control of all single battery cells of the battery, the equalization amount corresponding to each single battery cell is determined according to the feature inflection point corresponding to each single battery cell, so that after the equalization control of all single battery cells, the plurality of single battery cells of the battery reach a more ideal equalization state.

[0152] Further, after the equalization control of all single battery cells of the battery, the controller can determine that the capacity of all single battery cells is relatively balanced, at this time, the starting point value of the next discharge interval is determined as the initial starting point value. That is, after the equalization control of all single battery cells, the starting point value of the next discharge interval is updated to the starting point value, i.e., the SOC_Ah0 is updated to the initial starting point value = 40%, so that in the next charging, based on the starting point value of the next discharge interval, it is evaluated whether the battery needs to be charged based on the charging current value in the current discharge interval.

[0153] In an embodiment, as shown in FIG. 4, after the equalization control of all single battery cells of the battery, the charge and discharge control method includes:

[0154] updating the current state of the battery to an ideal equalization state, and recording the equalization time of the ideal equalization state at the current time.

[0155] The ideal equalization state is the state of all single battery cells of the battery after equalization control. The equalization time refers to the time when the current state is updated to the ideal equalization state.

[0156] As an example, after the controller performs equalization control on all individual cells of the battery, that is, controls the discharge switch corresponding to each individual cell to be turned on, so that the corresponding discharge circuit discharges, so that the charge of all individual cells reaches a relatively balanced state, the current state of the battery can be updated to the ideal equalization state, and the equalization time of the current ideal equalization state can be recorded. So that when the battery is in DC charging mode, the new current interval can be determined based on the updated equalization time of the ideal equalization state, thereby evaluating whether the current reduction equalization condition is met, and determining whether current reduction equalization control is needed.

[0157] In one embodiment, as shown in FIG4, battery equalization control includes:

[0158] If the characteristic inflection points of multiple individual battery cells include the characteristic inflection point of the highest voltage battery cell but do not include the characteristic inflection point of the lowest voltage battery cell, then the highest voltage battery cell is controlled to discharge based on the first equalization amount.

[0159] The first equalization amount is a pre-set equalization amount used to control the equalization of individual cells. The first equalization amount can be an equalization amount determined through multiple tests for equalization control. For example, the first equalization amount can be the first equalization SOC, which can be set to 3%, or it can be the first equalization capacity, which can be determined according to the actual situation. In this example, the first equalization SOC is used as an example for explanation.

[0160] As an example, the characteristic inflection points of multiple individual cells within the current current reduction range include the characteristic inflection point of the highest voltage cell but not the characteristic inflection point of the lowest voltage cell. That is, when the characteristic inflection point of the highest voltage cell is within the current current reduction range, while the characteristic inflection point of the lowest voltage cell is not within the current current reduction range, it can be determined that the charge deviation of all individual cells is large. At this time, the highest voltage cell is controlled to discharge based on the first equalization quantity, that is, the discharge circuit of the highest voltage cell is controlled to work to discharge the charge corresponding to the first equalization quantity, so as to reduce the charge of the highest voltage cell and thus ensure the purpose of equalization control.

[0161] In one embodiment, as shown in FIG4, the charge / discharge control method further includes:

[0162] Each first single cell is controlled to discharge based on the second equalization amount corresponding to the first single cell. The first single cell is a single cell other than the highest voltage cell whose characteristic inflection point is in the current current reduction range. The second equalization amount is less than the first equalization amount.

[0163] The second equalization amount is an equalization amount dynamically determined for controlling the first single battery cell to perform equalization control. For example, the second equalization amount can be a second equalization SOC or a second equalization capacity. The first single battery cell refers to a single battery cell other than the highest voltage battery cell and having a characteristic inflection point within the current discharge interval.

[0164] As an example, when the controller determines that the characteristic inflection point of the highest voltage battery cell is within the current discharge interval and the characteristic inflection point of the lowest voltage battery cell is not within the current discharge interval, it can be determined that the characteristic inflection point of the highest voltage battery cell and at least one single battery cell other than the highest voltage battery cell is within the current discharge interval, and at least one single battery cell including the lowest voltage battery cell is not within the current discharge interval. That is, the electric quantity of the single battery cell having the characteristic inflection point within the current discharge interval is greater than the electric quantity of the single battery cell having the characteristic inflection point outside the current discharge interval. Therefore, the single battery cell other than the highest voltage battery cell and having the characteristic inflection point within the current discharge interval can be determined as the first single battery cell, and each first single battery cell is controlled to discharge based on the second equalization amount corresponding to the first single battery cell, that is, the discharge circuit of the first single battery cell is controlled to discharge the electric quantity corresponding to the second equalization amount, so that the electric quantity of the first single battery cell is reduced, thereby achieving the purpose of equalization control. In this example, since the electric quantity of the highest voltage battery cell is higher than the electric quantity of the first single battery cell, the highest voltage battery cell is controlled to discharge based on the larger first equalization amount, and the first single battery cell is controlled to discharge based on the smaller second equalization amount, so that the electric quantities of the plurality of single battery cells in the battery are substantially equalized.

[0165] In an embodiment, the second equalization amount is the difference between the first equalization amount and a third variation amount.

[0166] The third variation amount is determined based on the characteristic inflection point of the highest voltage battery cell and the characteristic inflection point of the first single battery cell.

[0167] The third variation amount is the equalization amount by which the first single battery cell discharges less than the highest voltage battery cell. The third variation amount can be a SOC variation amount or a capacity variation amount.

[0168] As an example, after the controller determines the single battery cell other than the highest voltage battery cell and having the characteristic inflection point within the current discharge interval as the first single battery cell, it needs to determine the third variation amount corresponding to the first single battery cell based on the characteristic inflection point of the highest voltage battery cell and the characteristic inflection point of the first single battery cell. For example, the third variation amount can be determined based on the difference between the characteristic inflection point of the highest voltage battery cell and the characteristic inflection point of the first single battery cell. Then, the controller can calculate the difference between the first equalization amount and the third variation amount, and determine the difference as the second equalization amount, so that the highest voltage battery cell is controlled to discharge based on the first equalization amount and the first single battery cell is controlled to discharge based on the second equalization amount, thereby substantially equalizing the electric quantities of the plurality of single battery cells in the battery.

[0169] For example, the first equalization amount is 3%, the characteristic inflection point of the highest voltage cell corresponds to a cell SOC of 45%, the characteristic inflection point of the first first single cell corresponds to a cell SOC of 44.7%, and the characteristic inflection point of the second first single cell corresponds to a cell SOC of 44.5%. The third change amount of the first first single cell is 45%-44.7%=0.3%, and the corresponding second equalization amount is 3%-0.3%=2.7%, i.e., the first first single cell needs to discharge 2.7% of the cell capacity. The third change amount of the second first single cell is 45%-44.5%=0.5%, and the corresponding second equalization amount is 3%-0.5%=2.5%, i.e., the second first single cell needs to discharge 2.5% of the cell capacity. Therefore, when the highest voltage cell is discharged based on the larger first equalization amount, the smaller the difference between the characteristic inflection point of at least one first single cell and the characteristic inflection point of the highest voltage cell, the smaller the second equalization amount needed to be discharged, so that the corresponding second equalization amount of each first single cell is dynamically determined based on the characteristic inflection point thereof.

[0170] In this example, after the controller controls the highest voltage cell to be discharged based on the first equalization amount and the first single cell to be discharged based on the second equalization amount, the measured change amount before and after the discharge of the battery needs to be determined, which is determined as the measured change amount. Then, the smaller value of the second change amount and the measured change amount is determined as the first change amount, so that the sum of the starting value of the current discharge interval and the first change amount is determined as the starting value of the next discharge interval. For example, when the second change amount is 3% and the measured change amount is represented by Qbal, the starting value of the next discharge interval is SOC_Ah0= SOC_Ah0+ SOC_Ah1= SOC_Ah0+ min(3%, Qbal), so that when charging next time, whether the battery needs to be charged based on the charging current value in the current discharge interval is evaluated based on the starting value of the next discharge interval.

[0171] In an embodiment, as shown in FIG. 4, the equalization control of the battery includes:

[0172] If the characteristic inflection points of the plurality of single cells include the characteristic inflection point of the lowest voltage cell and do not include the characteristic inflection point of the highest voltage cell, the second single cell is controlled to be discharged based on the first equalization amount, and the second single cell is a single cell without a characteristic inflection point in the current charging process.

[0173] As an example, when the characteristic inflection points of the plurality of single battery cells in the current discharge interval include the characteristic inflection point of the single battery cell with the lowest voltage and do not include the characteristic inflection point of the single battery cell with the highest voltage, the controller can determine that the characteristic inflection point of at least one single battery cell including the single battery cell with the lowest voltage is in the current discharge interval, and the characteristic inflection point of at least one single battery cell including the single battery cell with the highest voltage is not in the current discharge interval. That is, the amount of electricity of the single battery cell with the characteristic inflection point outside the current discharge interval is greater than the amount of electricity of the single battery cell with the characteristic inflection point in the current discharge interval, and at this time, the single battery cell without the characteristic inflection point in the current charging process can be determined as the second single battery cell, that is, the single battery cell with the characteristic inflection point outside the current discharge interval is determined as the second single battery cell. Then, all the second single battery cells can be controlled to be discharged based on the first equalization amount, so that the amount of electricity of the second single battery cell outside the current discharge interval and the amount of electricity of the single battery cell in the current discharge interval are substantially equalized.

[0174] In an embodiment, as shown in FIG. 4, the equalization control of the battery includes:

[0175] If the characteristic inflection points of the plurality of single battery cells include the characteristic inflection point of the single battery cell with the lowest voltage and do not include the characteristic inflection point of the single battery cell with the highest voltage, each third single battery cell is controlled to be discharged based on a third equalization amount corresponding to the third single battery cell, and the third single battery cell is a single battery cell with the characteristic inflection point in the current discharge interval except for the single battery cell with the lowest voltage, and the third equalization amount is less than or equal to the first equalization amount.

[0176] The third equalization amount is an equalization amount dynamically determined for controlling the third single battery cell to perform equalization control, which can be a third equalization SOC or a third equalization capacity.

[0177] As an example, when the characteristic inflection points of the plurality of single battery cells include the characteristic inflection point of the single battery cell with the lowest voltage and do not include the characteristic inflection point of the single battery cell with the highest voltage, the controller can determine the single battery cell with the characteristic inflection point in the current discharge interval except for the single battery cell with the lowest voltage as the third single battery cell, and control each third single battery cell to be discharged based on a third equalization amount corresponding to the third single battery cell, so that the discharge circuit of the third single battery cell discharges the amount of electricity corresponding to the third equalization amount, so that the amount of electricity of the third single battery cell is reduced, thereby achieving the purpose of equalization control. In this example, since the amount of electricity of the third single battery cell outside the current discharge interval is greater than the amount of electricity of the second single battery cell in the current discharge interval, the second single battery cell is controlled to be discharged based on the larger first equalization amount, and the third single battery cell is controlled to be discharged based on the smaller third equalization amount, so that the amounts of electricity of the plurality of single battery cells in the battery are substantially equalized.

[0178] As an example, after the controller controls the second single battery cell to discharge based on the larger first equalization amount and controls the third single battery cell to discharge based on the smaller third equalization amount, the controller also needs to determine the start value of the next discharge interval as the start value of the current discharge interval, i.e., SOC_Ah0' = SOC_Ah0, so that when the first measured data of the battery reaches the SOC_Ah0 of the next discharge interval in the next charging, the battery is charged based on the charging current value in the current discharge interval.

[0179] In an embodiment, the third equalization amount is determined based on the characteristic inflection point of the third single battery cell and the characteristic inflection point of the lowest voltage battery cell.

[0180] As an example, after the controller determines the single battery cell other than the lowest voltage battery cell as the third single battery cell at the characteristic inflection point within the current discharge interval, the controller also needs to determine the third equalization amount corresponding to the third single battery cell based on the characteristic inflection point of the third single battery cell and the characteristic inflection point of the lowest voltage battery cell. In this example, the controller can first calculate the difference between the characteristic inflection point of the third single battery cell and the characteristic inflection point of the lowest voltage battery cell, and determine the difference as the third equalization amount, so that the third single battery cell discharges based on the third equalization amount, and the amount of electricity of the third single battery cell after discharging is lower than the amount of electricity of the lowest voltage battery cell, thereby making the amounts of electricity of the plurality of single battery cells in the battery substantially equal.

[0181] For example, the SOC of the battery cell corresponding to the characteristic inflection point of the lowest voltage battery cell is 40%, the SOC of the battery cell corresponding to the characteristic inflection point of the first third single battery cell is 40.3%, and the SOC of the battery cell corresponding to the characteristic inflection point of the second third single battery cell is 40.7%. The third equalization amount of the first third single battery cell is third equalization SOC = 40.3% - 40% = 0.3%, i.e., the first third single battery cell needs to discharge 0.3% of the battery capacity. The third equalization amount of the second third single battery cell is third equalization SOC = 40.7% - 40% = 0.7%, i.e., the second third single battery cell needs to discharge 0.7% of the battery capacity. When the third single battery cell and the lowest voltage battery cell are both within the current discharge interval, the third single battery cell needs to discharge based on the third equalization amount, and the smaller the difference between the characteristic inflection point of the third single battery cell and the characteristic inflection point of the lowest voltage battery cell, the smaller the third equalization amount that needs to be discharged, so that each third single battery cell dynamically determines the second equalization amount corresponding thereto based on the characteristic inflection point thereof.

[0182] In an embodiment, after the battery is controlled for equalization, the charging and discharging control method further comprises:

[0183] When the SOC of the battery cell of the highest voltage battery cell is greater than the preset SOC threshold value, the start value of the next discharge interval is determined as the initial start value.

[0184] The preset SOC threshold is a threshold preset for evaluating whether the cell capacity reaches a large standard, for example, the preset SOC threshold can be set to 95%. The initial starting point value is a starting point value preset for implementing the current reduction control, for example, the initial starting point value can be set to 40%.

[0185] As an example, the controller obtains the cell capacity of the highest voltage cell after the battery is subjected to the equalization control, that is, when the first measured data of the battery reaches the end point value of the current current reduction interval, compares the cell capacity with the preset SOC threshold, and if the cell capacity is greater than the preset SOC threshold, determines that the cell capacity of the highest voltage cell is large. In order to ensure the feasibility of the next current reduction equalization operation, it is necessary to determine that the starting point value of the next current reduction interval is the initial starting point value, so that based on the starting point value of the next current reduction interval, it is evaluated whether the battery needs to be charged based on the charging current value in the current current reduction interval.

[0186] In an embodiment, as shown in FIG. 4, the charge and discharge control method further comprises:

[0187] When the current current reduction interval does not include the characteristic inflection point of the single cell, the starting point value of the next current reduction interval is determined based on the maximum voltage difference of the plurality of single cells in the current current reduction interval.

[0188] As an example, when the current current reduction interval does not include the characteristic inflection point of the single cell, the controller needs to detect the battery to determine the plurality of cell voltages collected by the plurality of single cells in the current current reduction interval, determine the maximum cell voltage and the minimum cell voltage of the single cell from the plurality of cell voltages collected in the current current reduction interval, and determine the difference between the maximum cell voltage and the minimum cell voltage as the maximum voltage difference of the single cell in the current current reduction interval. Then, the controller analyzes the maximum voltage difference of the plurality of single cells in the current current reduction interval to determine the power deviation of the plurality of single cells, and then updates the starting point value of the next current reduction interval based on the power deviation of the plurality of single cells, so that the next current reduction interval is determined as a new current current reduction interval when the battery is next charged, and the battery is charged based on the charging current value in the current current reduction interval.

[0189] In an embodiment, as shown in FIG. 4, the starting point value of the next current reduction interval is determined based on the maximum voltage difference of the plurality of single cells in the current current reduction interval, comprising:

[0190] When the plurality of maximum voltage differences satisfy the preset pressure difference condition, the starting point value of the next current reduction interval is determined to be less than the starting point value of the current current reduction interval.

[0191] The preset pressure difference condition is a condition preset for evaluating whether the difference between the plurality of maximum voltage differences reaches a large standard.

[0192] As an example, the controller compares the maximum voltage differences of the plurality of single battery cells in the current discharge interval with the preset voltage difference condition, and when the maximum voltage differences of the plurality of single battery cells satisfy the preset voltage difference condition, it is determined that the differences between the maximum voltage differences of the plurality of single battery cells are large, and the current discharge interval is more likely to be between the characteristic inflection points of the lowest voltage battery cell and the highest voltage battery cell, and therefore, the starting point value of the next discharge interval needs to be reduced, so that in the next charging, based on the starting point value of the next discharge interval, it is evaluated whether the battery needs to be charged based on the charging current value in the current discharge interval, so as to track the highest voltage battery cell.

[0193] In an embodiment, as shown in FIG. 4, the starting point value of the next discharge interval is determined based on the maximum voltage differences of the plurality of single battery cells in the current discharge interval, including:

[0194] When the plurality of maximum voltage differences satisfy the preset voltage difference condition, the starting point value of the next discharge interval is determined as the difference between the starting point value of the current discharge interval and the second change amount.

[0195] As an example, the controller compares the maximum voltage differences of the plurality of single battery cells in the current discharge interval with the preset voltage difference condition, and when the maximum voltage differences of the plurality of single battery cells satisfy the preset voltage difference condition, it is determined that the differences between the maximum voltage differences of the plurality of single battery cells are large, and the current discharge interval is more likely to be between the characteristic inflection points of the lowest voltage battery cell and the highest voltage battery cell, and therefore, the starting point value of the next discharge interval needs to be reduced, so that in the next charging, based on the starting point value of the next discharge interval, it is evaluated whether the battery needs to be charged based on the charging current value in the current discharge interval, so as to track the highest voltage battery cell.

[0196] In an embodiment, as shown in FIG. 4, the starting point value of the next discharge interval is determined based on the maximum voltage differences of the plurality of single battery cells in the current discharge interval, including:

[0197] When the plurality of maximum voltage differences do not satisfy the preset voltage difference condition, the starting point value of the next discharge interval is determined to be greater than the starting point value of the current discharge interval.

[0198] As an example, the controller compares the maximum voltage difference of the plurality of single battery cells in the current discharge interval with a preset voltage difference condition, and when the maximum voltage difference of the plurality of single battery cells does not satisfy the preset voltage difference condition, it can be determined that the difference between the maximum voltage differences of the plurality of single battery cells is small, and the probability that the current discharge interval is between the characteristic inflection point of the lowest voltage battery cell and the characteristic inflection point of the highest voltage battery cell is small, so that in the next charging, based on the starting value of the next discharge interval, it is evaluated whether the battery needs to be charged based on the charging current value in the current discharge interval to achieve dynamic adjustment of the starting value.

[0199] In an embodiment, as shown in FIG. 4, the starting value of the next discharge interval is determined based on the maximum voltage difference of the plurality of single battery cells in the current discharge interval, including:

[0200] When the plurality of maximum voltage differences do not satisfy the preset voltage difference condition, the starting value of the next discharge interval is determined as the sum of the starting value of the current discharge interval and the second change amount.

[0201] As an example, the controller compares the maximum voltage difference of the plurality of single battery cells in the current discharge interval with a preset voltage difference condition, and when the maximum voltage difference of the plurality of single battery cells does not satisfy the preset voltage difference condition, it can be determined that the difference between the maximum voltage differences of the plurality of single battery cells is small, and the probability that the current discharge interval is between the characteristic inflection point of the lowest voltage battery cell and the characteristic inflection point of the highest voltage battery cell is small, and the starting value can be updated as the sum of the starting value and the second change amount, for example, when the starting value is SOC_Ah0 and the second change amount is 3%, update SOC_Ah0' = SOC_Ah0 + 3%, so that in the next charging, based on the starting value of the next discharge interval, it is evaluated whether the battery needs to be charged based on the charging current value in the current discharge interval to achieve dynamic adjustment of the starting value.

[0202] In an embodiment, the preset voltage difference condition is that the average voltage difference of the battery cells is greater than a preset voltage difference threshold;

[0203] The average voltage difference of the battery cells is the average of the maximum voltage difference of the plurality of single battery cells in the current discharge interval.

[0204] As an example, in the process of balancing control of the battery based on the feature inflection point balancing strategy, the battery needs to be detected, and the maximum cell voltage and the minimum cell voltage of the single battery are determined from the multiple cell voltages collected in the current discharge interval. The difference between the maximum cell voltage and the minimum cell voltage is determined as the maximum voltage difference of the single battery in the current discharge interval. Then, the maximum voltage differences of the multiple single batteries in the current discharge interval are calculated to obtain the average cell voltage difference. The average cell voltage difference is compared with the preset voltage difference threshold. If the average cell voltage difference is greater than the preset voltage difference threshold, it indicates that the average cell voltage difference is large. In this case, the current discharge interval is more likely to be between the feature inflection point of the lowest voltage battery and the feature inflection point of the highest voltage battery. Therefore, it is determined that the preset voltage difference condition is met. Conversely, if the average cell voltage difference is not greater than the preset voltage difference threshold, it indicates that the average cell voltage difference is small. In this case, the current discharge interval is less likely to be between the feature inflection point of the lowest voltage battery and the feature inflection point of the highest voltage battery. Therefore, it is determined that the preset voltage difference condition is not met.

[0205] In an embodiment, the charge and discharge control method further comprises:

[0206] When the first measured SOC of the battery is in the current discharge interval, the battery is charged based on the first charging current.

[0207] The first charging current refers to the charging current determined based on the discharge charging strategy. The discharge charging strategy refers to a strategy of reducing the charging current. The discharge charging strategy is a strategy different from the normal charging strategy, and is used to ensure that the feature inflection point of the battery can be detected during the charging process.

[0208] As an example, during the charging of the battery, the controller can obtain the first measured data corresponding to the battery, compare the first measured data with the current discharge interval, and charge the battery based on the first charging current when the first measured data of the battery is in the current discharge interval. Since the first charging current is small, the feature inflection point of the single battery can be detected. For example, when the first measured data of the battery is in the current discharge interval, 0.2C or other smaller first charging current can be used to charge the battery to ensure that the feature inflection point of the single battery can be detected, so that different strategies can be used to determine the start value of the next discharge interval and perform different balancing control according to whether the feature inflection points of the multiple single batteries fall into the current discharge interval.

[0209] In an embodiment, the charge and discharge control method further comprises:

[0210] When the first measured SOC of the battery is not in the current discharge interval, the battery is charged based on the second charging current, and the second charging current is greater than the first charging current.

[0211] wherein the second charging current refers to a charging current determined based on a normal charging strategy. The normal charging strategy refers to a strategy of normal charging according to actual needs.

[0212] As an example, during charging of the battery, the controller can acquire first measured data corresponding to the battery, compare the first measured data with the current drop current interval, and charge the battery based on the second charging current when the first measured data of the battery is not within the current drop current interval. Since the second charging current is greater than the first charging current, the charging efficiency of the battery can be guaranteed. For example, during charging of the battery, the controller can acquire first measured data corresponding to the battery, compare the first measured data with the current drop current interval, and charge the battery using 0.5C or a second charging current determined according to charging needs when the first measured data of the battery is not within the current drop current interval, so as to guarantee the charging efficiency. In this example, the first measured data of the battery is not within the current drop current interval, which can be that the first measured data is less than the starting value of the current drop current interval, or that the first measured data is greater than the ending value of the current drop current interval.

[0213] In an embodiment, the current drop current interval includes a starting value and an ending value, wherein the difference between the starting value and the ending value is equal in any two charging processes.

[0214] wherein the starting value and the ending value refer to two SOC thresholds of the current drop current interval, the starting value is an SOC used to control the start of drop charging of the battery, and the ending SOC is an SOC used to control the stop of the battery.

[0215] As an example, the current drop current interval includes a starting value and an ending value, the difference between the starting value and the ending value is equal in any two charging processes, for example, the difference between the two is ΔSOC, i.e., the ending value = the starting value + ΔSOC, so that after dynamically determining the starting value of each drop current interval, the corresponding ending value can be dynamically determined based on the difference between the starting value and the ending value, and the next drop current interval can be quickly updated and determined.

[0216] In addition, in an embodiment, the difference between the starting value and the ending value is equal in any two charging processes, i.e., the interval step of the drop current is the same, which avoids further reducing the charging time of the battery and causing user perception and other problems.

[0217] In an embodiment, before charging the battery based on the first charging current when the first measured SOC of the battery is within the current drop current interval, the charging and discharging control method further includes:

[0218] charging the battery based on the second charging current, the second charging current being greater than the first charging current;

[0219] determine the current current-drop interval based on the second measured SOC.

[0220] The second measured SOC refers to a measured SOC detected before the current current-drop interval is determined, and is a measured SOC used to dynamically determine the current current-drop interval. The second measured SOC can be determined by, but is not limited to, an ampere-hour integration method, an open-circuit voltage method, and a Kalman filtering algorithm.

[0221] As an example, the controller charges the battery based on the second charging current corresponding to the normal charging strategy to ensure that the battery is in a normal charging state, and acquires the second measured SOC of the battery. Then, the controller can specifically process the input parameter of the second measured SOC by using a pre-set current-drop interval determination rule to dynamically determine the current current-drop interval.

[0222] In an embodiment, the charging and discharging control method further includes:

[0223] The battery is charged based on the second charging current, and the second measured SOC of the battery is acquired when the current charging capacity reaches a pre-set charging capacity.

[0224] The current charging capacity is a charging capacity up to the current time. The pre-set charging capacity is a pre-set charging capacity, specifically a charging capacity used to evaluate whether the second measured SOC can be acquired.

[0225] As an example, the controller acquires the current charging capacity of the battery in real time during the charging process of the battery based on the second charging current. The current charging capacity can be understood as a charging capacity from the start of charging to the current time. After determining the current charging capacity of the battery, the controller can compare the current charging capacity with the pre-set charging capacity. If the current charging capacity reaches the pre-set charging capacity, it indicates that the charging power supply can normally charge the battery. At this time, the second measured SOC of the battery can be acquired to determine the current current-drop interval based on the second measured SOC. In this example, the battery is charged based on the larger second charging current, and the second measured SOC of the battery is acquired when the current charging capacity of the battery reaches the pre-set charging capacity, to ensure that the battery is in an acceptable charging state, thereby guaranteeing the feasibility of subsequent current-drop charging and balancing control.

[0226] In an embodiment, the current current-drop interval is determined based on the second measured SOC, including:

[0227] The larger value of the second measured SOC and the start value of the pre-set current-drop interval is determined as the start value of the current current-drop interval.

[0228] The sum of the start value of the current current-drop interval and the pre-set step length is determined as the end value of the current current-drop interval.

[0229] The preset step length is a preset step length for reflecting the start value and the end value of any flow reduction interval. Generally, the preset step length is usually in the SOC interval of 10% to 20%, for example, the preset step length can be set to 15% or other fixed values. Selecting the preset step length in the above range can ensure that a certain number of battery cells in the interval can detect the characteristic inflection point, and on the other hand, it can not further reduce the charging time of the battery.

[0230] As an example, the controller can compare the second measured SOC and the start value, and determine the larger value of the second measured SOC and the start value as the current flow reduction interval start value, to quickly determine the dynamically changing start value. For example, the second measured SOC is SOC_Ah2, the start value is SOC_Ah0, and the preset step length is 15%. When SOC_Ah1 < SOC_Ah0, it can be determined that the current flow reduction interval is [SOC_Ah0, SOC_Ah0+15%], otherwise, when SOC_Ah1 ≥ SOC_Ah0, it can be determined that the current flow reduction interval is [SOC_Ah1, SOC_Ah1+15%].

[0231] In an embodiment, the charge and discharge control method further comprises:

[0232] Obtaining first battery data of the battery, and determining the current flow reduction interval when the first battery data meets the flow reduction balancing condition.

[0233] The first battery data is data related to the battery determined at the current time. The flow reduction balancing condition is a condition preset for evaluating whether the flow reduction charging and balancing control is met.

[0234] As an example, when the battery is in a charging preparation state, that is, the battery is electrically connected with the charging power supply and can be charged at any time, the controller needs to obtain the first battery data corresponding to the battery in real time, and compare the first battery data with the preset flow reduction balancing condition. According to the comparison result, different charge and discharge strategies are determined. When the first battery data meets the preset flow reduction balancing condition, the controller needs to determine the current flow reduction interval first. The current flow reduction interval can be the next flow reduction interval updated after the last charging, or the current flow reduction interval dynamically determined according to the second measured SOC of the battery. Understandably, after the controller determines the current flow reduction interval, the battery is charged based on the first charging current corresponding to the flow reduction charging strategy, so that the characteristic inflection points of all single battery cells corresponding to the battery charging process can be detected, and then the characteristic inflection point balancing strategy is executed to balance the multiple single battery cells according to the detected all characteristic inflection points, so as to protect the power balance of the multiple single battery cells of the battery.

[0235] In the example, when the first battery data of the battery satisfies the current reduction equalization condition, the current reduction charging strategy is executed to charge the battery, so that the feature turning points of all single cells can be detected during the charging of the battery, the situation that the feature turning points of some single cells cannot be detected due to the large current charging of the battery can be avoided, the feasibility of the equalization control of the feature turning point equalization strategy is ensured, and the equalization of the electric quantity of the multiple single cells of the battery is realized.

[0236] In an embodiment, the first battery data includes a current charging mode and a current interval duration, and the current interval duration is a difference between a current time and an equalization time of a last ideal equalization state.

[0237] The current reduction equalization condition includes that the current charging mode is a direct current charging mode, and the current interval duration is greater than a preset interval duration.

[0238] The current charging mode refers to the charging mode at the current time, and the current charging mode can be a direct current charging mode or an alternating current charging mode. The current interval duration refers to a difference between the current time and an equalization time of a current state of the battery being an ideal equalization state, and is used to reflect how long the battery has not entered the ideal equalization state. The preset interval duration is a threshold value that is preset to evaluate whether the interval duration reaches a long standard.

[0239] As an example, the controller needs to obtain the current charging mode and the current interval duration when the battery is in a charging preparation state. When the current charging mode is a direct current charging mode, it indicates that the feature turning points of the single cells cannot be detected due to the large charging current, and the current reduction control needs to be performed. When the current interval duration is greater than the preset interval duration, it can be determined that the battery has not entered the ideal equalization state for a long time, and the equalization control of the multiple single cells of the battery needs to be performed. Therefore, it is determined that the first battery data of the battery satisfies the current reduction equalization condition, so as to subsequently perform the current reduction charging and equalization control.

[0240] In an embodiment, the first battery data includes a current charging mode and a current interval duration, and the current interval duration is a difference between a current time and an equalization time of a last ideal equalization state.

[0241] After obtaining the first battery data corresponding to the battery, the charging and discharging control method further includes:

[0242] When the current charging mode is a direct current charging mode, and the current interval duration is not greater than the preset interval duration, the battery is charged based on a second charging current, and the second charging current is greater than the first charging current.

[0243] As an example, the controller needs to obtain the current charging mode and the current interval duration when the battery is in the charging preparation state. When the current charging mode is the direct current charging mode, it indicates that the feature inflection point of the single battery cell can not be detected due to the large charging current, but since the current interval duration is not greater than the preset interval duration, it can be determined that the time interval from the last time the ideal balanced state is reached is short, and the probability of the multiple single battery cells of the battery being out of balance is small, so there is no need to perform balancing control on the multiple single battery cells of the battery. Therefore, the battery can be directly charged based on the second charging current. Since the second charging current is greater than the first charging current, the charging efficiency of the battery can be ensured.

[0244] In an embodiment, the first battery data includes a current charging mode;

[0245] After obtaining the first battery data corresponding to the battery, the charge and discharge control method further includes:

[0246] When the current charging mode is the alternating current charging mode, the battery is charged based on the second charging current, and balancing control is performed on all single battery cells of the battery. The second charging current is greater than the first charging current.

[0247] As an example, the controller needs to obtain the current charging mode when the battery is in the charging preparation state. When the current charging mode is the alternating current charging mode, since the charging current in the alternating current charging mode is generally small, the feature inflection point of all single battery cells can be detected during the charging process. Therefore, the battery can be directly charged based on the second charging current of the normal charging strategy to ensure the charging efficiency of the battery, and balancing control is performed on all single battery cells of the battery to ensure the balance of the electric quantity of the multiple single battery cells of the battery.

[0248] In the above embodiment, the charge and discharge control method is generally applied to a lithium iron phosphate battery or other battery types containing a two-end voltage platform in the middle section. Specifically, when charging the battery, there will be a voltage platform region. Because the voltage variation amplitude is small in this platform region, the capacity of the multiple single battery cells can be determined by applying the charge and discharge control method disclosed in the present application, and then the capacity difference between the multiple single battery cells is determined to improve the service life of the battery. The battery containing a two-end voltage platform in the middle section refers to a battery whose charging process includes two slope sections and a platform end, and the platform end is located between the two slope sections.

[0249] It should be understood that the size of the serial number of each step in the above embodiment does not mean the order of execution. The execution order of each process should be determined by its function and inherent logic, and should not constitute any limitation on the implementation process of the embodiments of the present application.

[0250] In an embodiment, a controller is provided, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, the processor implementing the charging and discharging control method in the above embodiments when executing the computer program, which will not be repeated here for the sake of brevity.

[0251] In an embodiment, a charging and discharging control system is provided, comprising a battery and the above controller, the controller being connected to the battery, the controller implementing the charging and discharging control method in the above embodiments, which will not be repeated here for the sake of brevity.

[0252] In an embodiment, a computer readable storage medium is provided, the computer readable storage medium storing a computer program, the computer program being executable on a processor to implement the charging and discharging control method in the above embodiments, which will not be repeated here for the sake of brevity.

[0253] In an embodiment, an electrical equipment is provided, comprising the above controller, or the above charging and discharging control system, or the above computer readable storage medium. For example, the electrical equipment can be, but is not limited to, a vehicle.

[0254] It is understood by those skilled in the art that all or part of the processes in the above embodiments can be completed by a computer program instructing relevant hardware, and the computer program can be stored in a non-volatile computer readable storage medium, and when executed, can include the processes of the above embodiments. Any reference to memory, storage, database or other medium in the embodiments provided by the present application can include non-volatile and / or volatile memory. Non-volatile memory can include read-only memory (ROM), programmable ROM (PROM), electrically programmable ROM (EPROM), electrically erasable programmable ROM (EEPROM) or flash memory. Volatile memory can include random access memory (RAM) or external cache memory. As an illustration but not limitation, RAM is available in various forms, such as static RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), double data rate SDRAM (DDR SDRAM), enhanced SDRAM (ESDRAM), synchronous link (Synchlink) DRAM (SLDRAM), memory bus (Rambus) direct RAM (RDRAM), direct memory bus dynamic RAM (DRDRAM), and memory bus dynamic RAM (RDRAM), etc.

[0255] Those skilled in the art can clearly understand that, for the convenience and brevity of description, only the above-mentioned division of each functional unit and module is exemplified, and in actual application, the above-mentioned functions can be completed by different functional units and modules according to needs, that is, the internal structure of the device is divided into different functional units or modules to complete all or part of the functions described above.

[0256] The above-described embodiments are only used to illustrate the technical solutions of the present application, rather than limit them; although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that: it can still modify the technical solutions recorded in the foregoing embodiments, or make equivalent replacement for part of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application, and should be included in the protection scope of the present application.

Claims

1. A charge and discharge control method characterized by comprising: The method comprises: determining a starting point value of a next current drop interval based on the characteristic inflection points of the plurality of single battery cells in a current drop interval during battery charging; wherein the charging current value in the current drop interval is less than the charging current value in a non-drop interval.

2. The method of claim 1, wherein, The method further comprises: determining a voltage characteristic inflection point based on the voltage-charge curve corresponding to each single battery cell; determining the characteristic inflection point of the single battery cell based on the voltage characteristic inflection point and the voltage-charge curve corresponding to the single battery cell.

3. The method of claim 1, wherein, The determination of the starting point value of the next current drop interval based on the characteristic inflection points of the plurality of single battery cells in the current drop interval during battery charging comprises: determining at least one of the characteristic inflection point of the single battery cell with the highest voltage and the characteristic inflection point of the single battery cell with the lowest voltage based on the characteristic inflection points of the plurality of single battery cells; determining the starting point value of the next current drop interval based on at least one of the characteristic inflection point of the single battery cell with the highest voltage and the characteristic inflection point of the single battery cell with the lowest voltage and the current drop interval; wherein the single battery cell with the highest voltage is the single battery cell with the highest voltage among the plurality of single battery cells, and the single battery cell with the lowest voltage is the single battery cell with the lowest voltage among the plurality of single battery cells.

4. The method of claim 1, wherein, The determination of the starting point value of the next current drop interval based on the characteristic inflection points of the plurality of single battery cells in the current drop interval during battery charging comprises: if the characteristic inflection points of the plurality of single battery cells include the characteristic inflection point of the single battery cell with the highest voltage and the characteristic inflection point of the single battery cell with the lowest voltage, the starting point value of the next current drop interval is an initial starting point value or the starting point value of the current drop interval, wherein the single battery cell with the highest voltage is the single battery cell with the highest voltage among the plurality of single battery cells, and the single battery cell with the lowest voltage is the single battery cell with the lowest voltage among the plurality of single battery cells.

5. The method of claim 1, wherein, The determination of the starting point value of the next current drop interval based on the characteristic inflection points of the plurality of single battery cells in the current drop interval during battery charging comprises: if the characteristic inflection points of the plurality of single battery cells include the characteristic inflection point of the single battery cell with the highest voltage and do not include the characteristic inflection point of the single battery cell with the lowest voltage, the starting point value of the next current drop interval is greater than the starting point value of the current drop interval, wherein the single battery cell with the highest voltage is the single battery cell with the highest voltage among the plurality of single battery cells, and the single battery cell with the lowest voltage is the single battery cell with the lowest voltage among the plurality of single battery cells.

6. The method of claim 5, wherein, The determination of the starting point value of the next current drop interval based on the characteristic inflection points of the plurality of single battery cells in the current drop interval during battery charging comprises: if the characteristic inflection points of the plurality of single battery cells include the characteristic inflection point of the single battery cell with the highest voltage and do not include the characteristic inflection point of the single battery cell with the lowest voltage, the starting point value of the next current drop interval is the sum of the starting point value of the current drop interval and a first change amount.

7. The method of claim 6, wherein, The first change amount is the smaller value of a second change amount and a measured change amount; the measured change amount is the equalization change amount of the battery in this equalization control.

8. The method of claim 1, wherein, The determination of the starting point value of the next current drop interval based on the characteristic inflection points of the plurality of single battery cells in the current drop interval during battery charging comprises: If the characteristic inflection points of the plurality of single battery cells include the characteristic inflection point of the single battery cell with the lowest voltage and do not include the characteristic inflection point of the single battery cell with the highest voltage, the starting point value of the next current reduction interval is the starting point value of the current current reduction interval, wherein the single battery cell with the highest voltage is the single battery cell with the highest voltage among the battery cells, and the single battery cell with the lowest voltage is the single battery cell with the lowest voltage among the battery cells.

9. The method of claim 1, wherein, The method further includes: If the characteristic inflection points of the plurality of single battery cells do not include the characteristic inflection point of the single battery cell with the highest voltage and the characteristic inflection point of the single battery cell with the lowest voltage, the starting point value of the next current reduction interval is less than the starting point value of the current current reduction interval, wherein the single battery cell with the highest voltage is the single battery cell with the highest voltage among the battery cells, and the single battery cell with the lowest voltage is the single battery cell with the lowest voltage among the battery cells.

10. The method of claim 9, wherein, The method further includes: If the characteristic inflection points of the plurality of single battery cells do not include the characteristic inflection point of the single battery cell with the highest voltage and the characteristic inflection point of the single battery cell with the lowest voltage, the starting point value of the next current reduction interval is the difference between the starting point value of the current current reduction interval and a second change amount.

11. The method according to any one of claims 3-10, characterized in that, The method further includes: The method further includes:

12. The method of claim 11, wherein, The equalization control of the battery includes: If the characteristic inflection points of the plurality of single battery cells include the characteristic inflection point of the single battery cell with the highest voltage and the characteristic inflection point of the single battery cell with the lowest voltage, the equalization control is performed on all single battery cells of the battery.

13. The method of claim 11, wherein, After the equalization control of all single battery cells of the battery, the charge and discharge control method includes: The current state of the battery is updated to an ideal equalization state, and the current time is recorded as an equalization time of the ideal equalization state.

14. The method of claim 11, wherein, The equalization control of the battery includes: If the characteristic inflection points of the plurality of single battery cells include the characteristic inflection point of the single battery cell with the highest voltage and do not include the characteristic inflection point of the single battery cell with the lowest voltage, the single battery cell with the highest voltage is controlled to be discharged based on a first equalization amount.

15. The method of claim 14, wherein, The method further includes: Each first single battery cell is controlled to be discharged based on a second equalization amount corresponding to the first single battery cell, wherein the first single battery cell is a single battery cell other than the single battery cell with the highest voltage among the single battery cells with the characteristic inflection points within the current current reduction interval, and the second equalization amount is less than the first equalization amount.

16. The method of claim 15, wherein, The second equalization amount is the difference between the first equalization amount and a third change amount. The third change amount is determined based on the characteristic inflection point of the single battery cell with the highest voltage and the characteristic inflection point of the first single battery cell.

17. The method of claim 11, wherein, The equalization control of the battery includes: If the characteristic inflection points of the plurality of single battery cells include the characteristic inflection point of the single battery cell with the lowest voltage and do not include the characteristic inflection point of the single battery cell with the highest voltage, the second single battery cell is controlled to be discharged based on a first equalization amount, and the second single battery cell is a single battery cell without the characteristic inflection point in the current charging process.

18. The method of claim 11, wherein, The equalization control of the battery includes: If the characteristic turning points of the plurality of single cells include the characteristic turning point of the lowest voltage cell and do not include the characteristic turning point of the highest voltage cell, each third single cell is controlled to be discharged based on a third equalization amount corresponding to the third single cell, the third single cell being the single cell other than the lowest voltage cell and having the characteristic turning point within the current discharge reduction interval, the third equalization amount being less than or equal to the first equalization amount.

19. The method of claim 18, wherein, The third equalization amount is determined based on the characteristic turning point of the third single cell and the characteristic turning point of the lowest voltage cell.

20. The method of claim 11, wherein, The method further comprises: When the cell SOC of the highest voltage cell is greater than a preset SOC threshold, the starting value of the next discharge reduction interval is determined as the initial starting value.

21. The method of claim 1, wherein, The method further comprises: When the characteristic turning point of the single cell is not included in the current discharge reduction interval, the starting value of the next discharge reduction interval is determined based on the maximum voltage difference of the plurality of single cells within the current discharge reduction interval.

22. The method of claim 21, wherein, The determination of the starting value of the next discharge reduction interval based on the maximum voltage difference of the plurality of single cells within the current discharge reduction interval comprises: When the plurality of maximum voltage differences satisfy a preset pressure difference condition, the starting value of the next discharge reduction interval is determined to be less than the starting value of the current discharge reduction interval.

23. The method of claim 22, wherein, The determination of the starting value of the next discharge reduction interval based on the maximum voltage difference of the plurality of single cells within the current discharge reduction interval comprises: When the plurality of maximum voltage differences satisfy a preset pressure difference condition, the starting value of the next discharge reduction interval is determined to be the difference between the starting value of the current discharge reduction interval and a second change amount.

24. The method of claim 21, wherein, The determination of the starting value of the next discharge reduction interval based on the maximum voltage difference of the plurality of single cells within the current discharge reduction interval comprises: When the plurality of maximum voltage differences do not satisfy the preset pressure difference condition, the starting value of the next discharge reduction interval is determined to be greater than the starting value of the current discharge reduction interval.

25. The method of claim 24, wherein, The determination of the starting value of the next discharge reduction interval based on the maximum voltage difference of the plurality of single cells within the current discharge reduction interval comprises: When the plurality of maximum voltage differences do not satisfy the preset pressure difference condition, the starting value of the next discharge reduction interval is determined to be the sum of the starting value of the current discharge reduction interval and a second change amount.

26. The method of any one of claims 22-25, wherein, The preset pressure difference condition is that a cell pressure difference average is greater than a preset pressure difference threshold. The cell pressure difference average is an average of the maximum voltage differences of the plurality of single cells within the current discharge reduction interval.

27. The method of claim 1, wherein, The method further comprises: When the first measured SOC of the battery is within the current discharge reduction interval, the battery is charged based on a first charging current.

28. The method of claim 27, wherein, The method further comprises: When the first measured SOC of the battery is not within the current discharge reduction interval, the battery is charged based on a second charging current, the second charging current being greater than the first charging current.

29. The method of claim 1, wherein, The current discharge reduction interval includes a starting value and an ending value, and the difference between the starting value and the ending value is equal in any two charging processes.

30. The method of claim 27, wherein, Before the battery is charged based on the first charging current when the first measured SOC of the battery is within the current discharge reduction interval, the charge and discharge control method further comprises: The battery is charged based on a second charging current, the second charging current being greater than the first charging current; determine the current current-reduction interval based on the second measured SOC.

31. The method of claim 30, wherein, The method further comprises: charging the battery based on a second charging current, and obtaining a second measured SOC of the battery when the current charging amount reaches a preset charging amount.

32. The method of claim 30, wherein, The determination of the current current-reduction interval based on the second measured SOC comprises: determining a larger value between the second measured SOC and a start value of a preset current-reduction interval as a start value of the current current-reduction interval; determining a sum of the start value of the current current-reduction interval and a preset step length as an end value of the current current-reduction interval.

33. The method of claim 27, wherein, The method further comprises: obtaining first battery data of the battery, and determining a current current-reduction interval when the first battery data satisfies a current-reduction balancing condition.

34. The method of claim 33, wherein, The first battery data comprises a current charging mode and a current interval length, and the current interval length is a difference between a current time and a balancing time of a last ideal balancing state. The current-reduction balancing condition comprises that the current charging mode is a direct-current charging mode, and the current interval length is greater than a preset interval length.

35. The method of claim 33, wherein, The first battery data comprises a current charging mode and a current interval length, and the current interval length is a difference between a current time and a balancing time of a last ideal balancing state. After the obtaining of the first battery data corresponding to the battery, the charging and discharging control method further comprises: when the current charging mode is a direct-current charging mode and the current interval length is not greater than a preset interval length, charging the battery based on a second charging current, and the second charging current is greater than the first charging current.

36. The method of claim 33, wherein, The first battery data comprises a current charging mode. After the obtaining of the first battery data corresponding to the battery, the charging and discharging control method further comprises: when the current charging mode is an alternating-current charging mode, charging the battery based on a second charging current, and performing balancing control on all single cells of the battery, and the second charging current is greater than the first charging current.

37. A controller comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein, The processor executes the computer program to implement the charging and discharging control method in any one of claims 1 to 36.

38. A charge-discharge control system characterized by comprising: The charging and discharging control system comprises a battery and a controller according to claim 37, and the controller is connected to the battery.

39. A computer-readable storage medium, the computer-readable storage medium storing a computer program, characterized in that, The computer program is executed by the processor to implement the charging and discharging control method in any one of claims 1 to 36.

40. An electrical device, comprising: The charging and discharging control system comprises the controller according to claim 37, or the charging and discharging control system according to claim 38, or the computer readable storage medium according to claim 39.

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