Battery equalization control method and device, electronic equipment and storage medium

Abstract

The invention relates to the technical field of battery equalization, in particular to a battery equalization control method and device, electronic equipment and a storage medium, and the method comprises the following steps: obtaining state information of a battery, the battery at least comprising a battery cell, the state information comprising current information, and voltage information and temperature information of the battery cell; according to the state information, estimating the capacity and internal resistance of the battery cell, and obtaining the equalization capacity of each equalized battery cell; removing abnormal cells according to the estimated cell capacity and internal resistance and the obtained equalization capacity of each equalized cell, and determining the cell with the minimum voltage in the residual cells as a reference cell; on the basis of the working condition of the battery, comparing each battery cell with the reference battery cell; correspondingly determining battery cells needing to be balanced according to different working conditions, and correspondingly formulating different balancing control strategies; on the premise of covering multiple battery working conditions, the execution efficiency of battery capacity equalization is improved, and the battery equalization control requirement can be met.

Description

Technical Field

[0001] This application relates to the technical field of battery balancing, and particularly to a battery balancing control method, device, electronic device, and storage medium. Background Art

[0002] A battery pack is formed by connecting multiple battery cells. However, when the state of the battery cells changes, the battery pack faces the risk of losing balance. This imbalance not only affects the ability of the battery to be fully charged or discharged, but also accelerates battery aging, reduces performance, and shortens the service life. The imbalance problem may occur during both the manufacturing and operation of the battery. During the battery manufacturing stage, due to slight differences in the state of charge (SOC), capacity, impedance, or service life of the battery cells, the assembled battery pack may be in an unbalanced state even at the initial use. During the operation process, design factors such as the arrangement and layout of the battery cells may also cause the battery pack to be unbalanced.

[0003] Battery balancing refers to ensuring that each cell in the battery pack can be effectively used and maintained in a healthy state through different technical means, including monitoring and maintaining the state of charge (SOC) of each battery cell to prevent damage to the battery cell due to overcharging / deep discharging. The purpose of battery balancing is to extend the system operation time, improve the charging efficiency, and reduce the reduction of battery life.

[0004] The common practice of battery balancing is to determine the balancing battery cells by estimating the capacity difference and determine the balancing time by the balancing current. However, due to the failure to consider the battery cells with smaller capacity, excessive discharging of the battery cells easily causes more system energy loss, and the abnormal battery cells interfere with the balancing control, resulting in low accuracy of the balancing control. In addition, due to the failure to consider the characteristics of the battery plateau region, it is impossible to determine the balancing battery cells and the balancing strategy according to different working conditions, and the battery balancing execution efficiency is low, making it difficult to meet the battery balancing control requirements. Summary of the Invention

[0005] The purpose of the present invention is to provide a battery balancing control method, device, electronic device, and storage medium, aiming to eliminate the interference of abnormal-capacity battery cells on the balancing control, determine the battery cells to be balanced and the balancing strategy according to different working conditions, and improve the accuracy and execution efficiency of the battery balancing control.

[0006] To achieve one of the foregoing purposes, according to one aspect of the present application, a battery balancing control method is provided, and the method includes the following steps: Obtain the state information of the battery, where the battery includes at least one battery cell, and the state information includes current information, voltage information of the battery cell, and temperature information; Estimate the capacity and internal resistance of the battery cell according to the state information, and obtain the balanced capacity of each balanced battery cell; The abnormal cells are eliminated according to the estimated cell capacity and internal resistance and the obtained balanced capacity of each balanced cell, and the cell with the minimum voltage among the remaining cells is determined as the reference cell; Based on the working condition of the battery, each of the battery cells is compared with the reference battery cell to determine the battery cell that needs to be balanced; According to the working condition of the battery, the balancing time or the balancing pressure difference of the battery cells that need to be balanced is calculated, and the balancing control of the battery cells that need to be balanced is performed based on the balancing time or the balancing pressure difference; The operating condition includes at least one of low SOC static, low SOC dynamic, platform area dynamic and charging end stage.

[0007] It can be learned that by estimating the capacity and internal resistance of the battery cells and counting the balanced capacity of each battery cell after balancing, it is convenient to eliminate abnormal batteries according to actual conditions, eliminate the interference of abnormal capacity batteries on the balancing control, thereby avoiding wrong balancing as much as possible, and thus improving the accuracy of balancing control; in addition, by determining the reference battery cell, it also provides a basis for determining the balanced battery cell; by judging the working state of the battery, it is convenient to determine the battery cells that need to be balanced according to different working conditions, and to formulate different balancing control strategies accordingly, through the low SOC static, low SOC dynamic, platform area dynamic, and charging end working condition division, on the premise of covering a variety of battery working conditions, different strategies are used to balance the battery, thereby improving the execution efficiency of battery capacity balancing, which can meet the battery balancing control needs.

[0008] In addition to one or more of the above, or as an alternative, in another embodiment, the method for estimating the capacity of each of the battery cells comprises the following steps: When the continuous charging or discharging capacity exceeds the preset value, the capacity of each battery cell is estimated by Qall=△Q / △SOC; Among them, Qall is the capacity of all battery cells, △Q is the capacity of continuous charging or discharging, and △SOC is the SOC change value of each battery cell.

[0009] In addition to one or more of the above, or as an alternative, in another embodiment, the method for removing abnormal cells according to the estimated cell capacity comprises the following steps: The estimated capacity of each battery cell is compared with the current battery cell capacity. When the ratio of the estimated battery cell capacity to the current battery cell capacity is less than a preset value, the battery cell is removed and cannot be used as a reference battery cell, where the current battery cell capacity = battery cell rated capacity × SOH.

[0010] In addition to one or more of the above, or as an alternative, in another embodiment, when the ratio of the estimated cell capacity to the current cell capacity is less than 95%, the cell to be excluded cannot be used as a reference cell.

[0011] In addition to one or more of the above, or as an alternative, in another embodiment, the internal resistance of the estimated cell includes respectively estimating the internal resistance of the cell with the maximum single - cell voltage, the internal resistance of the cell with the minimum single - cell voltage, and the internal resistance of the cell with the average cell voltage.

[0012] In addition to one or more of the above, or as an alternative, in another embodiment, the method for estimating the internal resistance of the cell includes the following steps: Jointly estimate the cell SOC and the ohmic internal resistance R0, combine with the second - order RC circuit model, discretize the model to obtain the following equation, and estimate the ohmic internal resistance R0 of the cell according to the following formula:

[0013] In addition to one or more of the above, or as an alternative, in another embodiment, the method for excluding abnormal cells according to the estimated internal resistance of the cell includes the following steps: Compare the internal resistance of the cell with the maximum single - cell voltage estimated with the internal resistance of the cell with the minimum single - cell voltage; When the ratio of the internal resistance of the cell with the maximum single - cell voltage to the internal resistance of the cell with the minimum single - cell voltage is greater than a preset value, the cell with the maximum single - cell voltage to be excluded cannot be used as a reference cell.

[0014] In addition to one or more of the above, or as an alternative, in another embodiment, the method for obtaining the equalized capacity of each equalized cell includes the following steps: Judge whether there are equalized cells in the battery. If so, obtain the equalized capacity of each equalized cell and use it as the basis for excluding the reference cell.

[0015] In addition to one or more of the above, or as an alternative, in another embodiment, the method for excluding abnormal cells according to the obtained equalized capacity of each equalized cell includes the following steps: When the statistical accumulation of the equalized capacity of each cell reaches a preset time, remove the cell with the minimum equalized capacity, and compare the equalized capacity of each remaining cell with the average equalized capacity; When there is a cell among the remaining cells whose ratio of the equalized capacity to the average equalized capacity is less than a preset value, the cell to be excluded cannot be used as a reference cell; Among them, the average equalization capacity is the average of the equalization capacities of the remaining cells after removing the cell with the minimum equalization capacity and the cell with the maximum equalization capacity.

[0016] In addition to one or more of the above, or as an alternative, in another embodiment, the determining the cells to be equalized based on the battery operating conditions includes the following steps: When the battery is in a low SOC state and has been static for a preset low-end static time, or when the battery is in a low SOC state and is undergoing dynamic charge and discharge, compare the SOC value of the current cell with the SOC value of the reference cell to determine the cells to be equalized; Among them, the preset low-end static time is configured as the time during which the voltage of the cell remains unchanged during the static process corresponding to different temperatures.

[0017] In addition to one or more of the above, or as an alternative, in another embodiment, when the battery is in a low SOC state and has been static to meet the preset low-end static time, obtain the SOC value of the current cell by looking up the OCV-SOC table according to the voltage of the cell, When the battery is in a low SOC state and is undergoing dynamic charge and discharge, calculate the SOC value of the current cell through the following formula: SOCmin + (SOCmax - SOCmin) / (Vmax - Vmin) × (V - Vmin); Among them, SOCmin and SOCmax respectively represent the minimum SOC and the maximum SOC in each cell, Vmax and Vmin respectively represent the maximum cell voltage and the minimum cell voltage, and V represents the voltage of any one cell.

[0018] In addition to one or more of the above, or as an alternative, in another embodiment, the comparing the SOC value of the current cell with the SOC value of the reference cell to determine the cells to be equalized includes the following steps: When the difference between the SOC of the current cell and the SOC of the reference cell is greater than 1%, determine that the current cell is a cell to be equalized; otherwise, the current cell does not need to be equalized.

[0019] In addition to one or more of the above, or as an alternative, in another embodiment, the determining the cells to be equalized based on the battery operating conditions further includes the following steps: When the battery is in the plateau region and is undergoing charge and discharge, or when the battery is in the charging state and the maximum voltage value of the cell exceeds the preset charging end voltage threshold: Judge whether the voltage difference between the current cell and the reference cell is greater than the preset voltage difference. If so, determine that the current cell is a cell to be equalized; if not, the current cell does not need to be equalized; Among them, the preset terminal charging voltage threshold is obtained by looking up the voltage corresponding to 95% SOC in the voltage table at different charging rates and temperatures.

[0020] In addition to one or more of the above, or as an alternative, in another embodiment, the equalization control of the cells to be equalized based on the equalization time or the equalization voltage difference includes the following steps: When the battery is in a low SOC static state or a low SOC dynamic working condition, equalization control is performed on the cells based on the equalization time; When the battery is in a dynamic state in the plateau region or at the end of charging, equalization control is performed on the cells based on the equalization voltage difference until the equalization voltage difference is less than or equal to a preset value; Among them, the equalization voltage difference is the voltage difference between the current cell and the reference cell.

[0021] In addition to one or more of the above, or as an alternative, in another embodiment, when the battery is in a low SOC state and has been static for a preset low-end static time, or when the battery is in a low SOC state and is undergoing dynamic charge and discharge, the formula for calculating the equalization time of the cells to be equalized is: equalization time = (△SOC - 1) × rated capacity × SOH / equalization current.

[0022] In addition to one or more of the above, or as an alternative, in another embodiment, after performing equalization control on the cells to be equalized, the following steps are further included: Output the equalization capacity values of each cell, which serve as the basis for determining the reference cell.

[0023] To achieve one of the foregoing purposes, according to another aspect of the present application, there is provided a battery equalization control device, which is applied to the battery equalization control method described in the foregoing aspect, and includes: An information acquisition module, configured to acquire the state information of the battery in real time and count the equalization capacity of each equalized cell; among them, the battery includes at least one cell, and the state information includes at least current information, voltage information of the cell, and temperature information; An information processing module, configured to estimate the capacity and internal resistance of the cell according to the state information, and eliminate abnormal cells based on the estimated capacity, internal resistance of the cell, and the acquired equalization capacity of each equalized cell, and determine the reference cell; An information operation module, configured to compare each cell with the reference cell based on the battery working condition, determine the cells to be equalized, and calculate the equalization time and equalization voltage difference of the cells to be equalized; An equalization control module, configured to perform equalization control on the cells to be equalized according to the equalization time and the equalization voltage difference, and output the equalization capacity values of each cell.

[0024] In order to achieve one of the aforementioned purposes, according to another aspect of the present application, there is provided an electronic device, comprising: a processor, and a memory connected to the processor; The memory is used to store a computer program; the processor is used to call and execute the computer program in the memory to perform the steps of the battery balancing control method as described above.

[0025] In order to achieve one of the aforementioned objectives, according to another aspect of the present application, a computer-readable storage medium is provided, on which a computer program is stored, and when the computer program is executed by a processor, the steps of the battery balancing control method described above are executed.

[0026] Compared with the prior art, the beneficial effects of the present invention are as follows: the battery balancing control method described in this article, by estimating the capacity and internal resistance of the battery cell and counting the balanced capacity of each battery cell after balancing, is convenient for eliminating abnormal batteries according to actual conditions, eliminating the interference of abnormal capacity batteries on balancing control, thereby avoiding erroneous balancing as much as possible, and thus improving the accuracy of balancing control; in addition, by determining the reference battery cell, it also provides a basis for determining the balanced battery cell; by judging the working state of the battery, it is convenient to determine the battery cell that needs to be balanced according to different working conditions, and to formulate different balancing control strategies accordingly, and by dividing the working conditions into low SOC static, low SOC dynamic, platform area dynamic, and charging end, different strategies are adopted to balance the battery on the premise of being able to cover a variety of battery working conditions, thereby improving the execution efficiency of battery capacity balancing, and meeting the battery balancing control requirements. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The disclosure of the present application will be more convenient to understand with reference to the accompanying drawings. It should be understood that these drawings are only for illustrative purposes and are not intended to limit the scope of protection of the present application.

[0028] In the figure: Figure 1 is a schematic diagram of the overall process of a battery balancing control method according to the present application; Figure 2 A battery balancing control method according to an embodiment of the present application is disclosed. Figure 1 ; Figure 3 A battery balancing control method according to an embodiment of the present application is disclosed. Figure 2 ; Figure 4 A battery balancing control method according to an embodiment of the present application is disclosed. Figure 3 ; Figure 5It is a block diagram of a battery balancing control device disclosed in an embodiment of the present application; Figure 6 It is a schematic diagram of the hardware structure of an electronic device disclosed in an embodiment of the present application. Detailed implementation manners

[0029] To make the objectives, technical solutions, and advantages of the embodiments of the present application clearer, the following will further describe the specific technical solutions of the present application in detail with reference to the accompanying drawings in the embodiments of the present application. The following embodiments are used to illustrate the present application but are not used to limit the scope of the present application.

[0030] In the embodiments of the present application, the terms "first" and "second" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, features defined with "first" and "second" may explicitly or implicitly include one or more of such features. In the description of the embodiments of the present application, unless otherwise stated, the meaning of "a plurality" is two or more.

[0031] In addition, in the embodiments of the present application, orientation terms such as "upper", "lower", "left", and "right" are defined relative to the orientation in which the components in the drawings are schematically placed. It should be understood that these directional terms are relative concepts, and they are used for relative description and clarification, and they may change accordingly with the change of the orientation in which the components in the drawings are placed.

[0032] In the embodiments of the present application, unless otherwise clearly specified and limited, the term "connection" should be understood in a broad sense. For example, "connection" can be a fixed connection, a detachable connection, or integrated; it can be directly connected or indirectly connected through an intermediate medium.

[0033] In the embodiments of the present application, the terms "include", "comprise", or any other variant thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or device including a series of elements not only includes those elements but also includes other elements not expressly listed, or also includes elements inherent to such process, method, article, or device. Without further limitation, an element defined by the phrase "including one..." does not exclude the existence of additional identical elements in the process, method, article, or device including such element.

[0034] In the embodiments of the present application, words such as "exemplary" or "for example" are used to indicate examples, illustrations, or explanations. Any embodiment or design solution described as "exemplary" or "for example" in the embodiments of the present application should not be construed as being more preferred or having more advantages than other embodiments or design solutions. Rather, the use of words such as "exemplary" or "for example" is intended to present relevant concepts in a specific manner.

[0035] At present, the common practice of battery balancing is to determine the balancing cells by estimating the capacity difference and determine the balancing time by the balancing current. Since the cells with smaller capacity are not considered, it is difficult to ensure the accuracy of battery balancing control. In addition, since too much discharge is performed on the system cells, it is easy to cause more energy loss in the system, so it is difficult to meet the requirement of accurate balancing of battery capacity.

[0036] Based on the discharge SOC-OCV curve of lithium iron phosphate battery in the prior art, it can be known that when the battery is in the plateau region, the overall curve slope is low, which reflects that when the current SOC changes greatly, the voltage only changes slightly. If the traditional method of determining the balancing cells by estimating the capacity difference through voltage is adopted, it will lead to a significant reduction in the balancing control efficiency in the plateau region. Therefore, the balancing control method of this application is proposed, which can determine the balancing cells and the balancing strategy according to different working conditions, and improve the accuracy and execution efficiency of battery balancing control.

[0037] Figure 1 It is a schematic flow chart of a battery balancing control method according to this application. The method includes the following steps: S1. Obtain the state information of the battery. The battery includes at least one cell, and the state information includes current information, voltage information of the cell, and temperature information; S2. Estimate the capacity and internal resistance of the cell according to the state information, and obtain the balancing capacity of each cell after balancing; S3. Eliminate abnormal cells according to the estimated capacity and internal resistance of the cell and the obtained balancing capacity of each cell after balancing, and determine the cell with the minimum voltage among the remaining cells as the reference cell; S4. Based on the working condition of the battery, compare each cell with the reference cell to determine the cells that need to be balanced; S5. According to the working condition of the battery, calculate the balancing time or the balancing voltage difference of the cells that need to be balanced, and perform balancing control on the cells that need to be balanced based on the balancing time or the balancing voltage difference; Wherein, the working condition includes at least one of low SOC static, low SOC dynamic, plateau region dynamic, and end of charge.

[0038] Under such an arrangement, a battery equalization control method described herein estimates the capacity and internal resistance of each battery cell and counts the equalization capacity of each battery cell after equalization, facilitating the elimination of abnormal battery cells according to the actual situation, excluding the interference of battery cells with abnormal capacity on equalization control, thus avoiding false equalization as much as possible and improving the accuracy of equalization control. In addition, by determining the reference battery cell, a basis is provided for determining the battery cells to be equalized. By judging the working condition state of the battery, it is convenient to determine the battery cells to be equalized and formulate different equalization control strategies according to different working conditions. Through the working condition division of low SOC static, low SOC dynamic, platform area dynamic, and the end stage of charging, on the premise of covering a variety of battery working conditions, different strategies are used to equalize the battery, thereby improving the execution efficiency of battery capacity equalization and meeting the equalization control requirements of the battery.

[0039] It should be noted that the battery equalization control method proposed by the present invention can significantly improve the overall equalization efficiency of the battery system by accurately identifying the battery cells to be equalized and optimizing the equalization control strategy, taking into account the battery cells with smaller capacity, thus reducing unnecessary energy loss, and therefore can meet the requirements of accurate equalization of battery capacity.

[0040] The following will introduce the further specific implementation, refinement, or improvement process of the battery equalization control method through exemplary descriptions, in order to further improve it or for other improvement considerations.

[0041] On this basis, referring to Figure 2 , in step S2, the method for estimating the capacity of each battery cell includes the following steps: S201. When the continuously charged or discharged capacity exceeds a preset value, estimate the capacity of each battery cell through Qall = △Q / △SOC; Where Qall is the capacity of all battery cells, △Q is the continuously charged or discharged capacity, and △SOC is the SOC change value of each battery cell.

[0042] It can be known that by estimating the capacity of each battery cell, a basis can be provided for eliminating abnormal battery cells to reduce the influence of battery cells with smaller capacity on equalization, making the battery equalization process more efficient and reliable.

[0043] Exemplarily, when the continuously charged or discharged capacity exceeds 50%, estimate the capacity of each battery cell through the above formula. It should be noted that too small a value above will lead to a large estimation error; of course, the above value can also be selected according to needs, and no specific limitation is made in this embodiment.

[0044] On this basis, referring to Figure 2 , in step S2, the method for estimating the internal resistance of the battery cell includes the following steps: S202. Estimate the internal resistance of the cell with the maximum single - cell voltage, the internal resistance of the cell with the minimum single - cell voltage, and the internal resistance of the cell with the average cell voltage respectively.

[0045] Specifically, when estimating the internal resistance of the cell, by jointly estimating the cell's state of charge (SOC) and Ohmic internal resistance R0, combining with a second - order RC circuit model, after model discretization, the following equation is obtained, and the Ohmic internal resistance R0 of the cell is estimated according to the following formula:

[0046] On this basis, referring to Figure 2 , in step S2, the method for obtaining the equalized capacity of each equalized cell includes the following steps: S203. Determine whether there are equalized cells in the battery. If so, obtain the equalized capacity of each equalized cell and use it as the basis for excluding the reference cell.

[0047] In one case of this embodiment, referring to Figure 3 , in step S3, the method for excluding abnormal cells according to the estimated cell capacity includes the following steps: S301. Compare the estimated capacity of each cell with the current cell capacity. When the ratio of the estimated cell capacity to the current cell capacity is less than a preset value, exclude this cell from being used as a reference cell, where the current cell capacity = cell rated capacity × state of health (SOH).

[0048] Specifically, when the ratio of the estimated cell capacity to the current cell capacity is less than 95%, exclude this cell from being used as a reference cell.

[0049] It should be noted that the ratio of the above - mentioned battery cell capacity to the current cell capacity can also be set as needed, as long as it can meet the actual requirements. This embodiment does not make specific limitations here.

[0050] In another case of this embodiment, referring to Figure 3 , in step S3, the method for excluding abnormal cells according to the estimated internal resistance of the cell includes the following steps: S302. Compare the internal resistance of the cell with the maximum single - cell voltage estimated with the internal resistance of the cell with the minimum single - cell voltage; When the ratio of the internal resistance of the cell with the maximum single - cell voltage to the internal resistance of the cell with the minimum single - cell voltage is greater than a preset value, exclude the cell with the maximum single - cell voltage from being used as a reference cell.

[0051] Exemplarily, if the ratio of the internal resistance of the cell with the maximum single - cell voltage to the internal resistance of the cell with the minimum single - cell voltage is greater than 5 times, it is considered that the cell with the maximum single - cell voltage is abnormal and needs to be excluded.

[0052] In another case of this embodiment, referring to Figure 3 , in step S3, the method of removing abnormal cells according to the balanced capacity of each balanced cell obtained includes the following steps: S303. When the statistics of the balanced capacity of each cell reach a preset time, remove the cell with the minimum balanced capacity, and compare the balanced capacity of each remaining cell with the average balanced capacity; When there is a cell among the remaining cells whose ratio of the balanced capacity to the average balanced capacity is less than a preset value, remove this cell as it cannot be used as a reference cell; Wherein, the average balanced capacity is the average value of the balanced capacities of the remaining other cells after removing the cell with the minimum balanced capacity and the cell with the maximum balanced capacity.

[0053] In one case of this embodiment, referring to Figure 4 , in step S4, determining the cells that need to be balanced based on the working condition of the battery includes the following steps: S401. When the battery is in a low SOC state and has been static for a preset low-end static time, or when the battery is in a low SOC state and is undergoing dynamic charge and discharge, compare the SOC value of the current cell with the SOC value of the reference cell to determine the cells that need to be balanced; Wherein, the preset low-end static time is configured as the time during which the voltage of the cell remains unchanged during the static process corresponding to different temperatures.

[0054] It can be known that when the battery is in a low SOC static state, the cells that need to be balanced can be determined by comparing the SOC value of the current cell with the SOC value of the reference cell.

[0055] In one case of this embodiment, referring to Figure 4 , when the battery is in a low SOC state and has been static until it meets the preset low-end static time, obtain the SOC value of the current cell by looking up the OCV-SOC table according to the voltage of the cell.

[0056] In another case of this embodiment, referring to Figure 4 , when the battery is in a low SOC state and is undergoing charge and discharge, calculate the SOC of the cell through the following formula: SOCmin + (SOCmax - SOCmin) / (Vmax - Vmin) × (V - Vmin); Wherein, SOCmin and SOCmax respectively represent the minimum SOC and the maximum SOC among the cells, Vmax and Vmin respectively represent the maximum cell voltage and the minimum cell voltage, and V represents the voltage of any one cell.

[0057] It is not difficult to see that when the battery is in a low SOC state and is being charged or discharged, the SOC of the other battery cells can be obtained first, and then the battery cells that need to be balanced can be determined, with more accurate data.

[0058] Exemplarily, referring to Figure 4 , under the two working conditions of low SOC static state and low SOC dynamic state, the method for determining the battery cells that need to be balanced is as follows: when the difference between the SOC of the current battery cell and the SOC of the reference battery cell is greater than 1%, it is determined that the current battery cell is the battery cell that needs to be balanced; otherwise, the current battery cell does not need to be balanced.

[0059] In another case of this embodiment, referring to Figure 4 , in step S4, the method for determining the battery cells that need to be balanced based on the working condition of the battery further includes the following steps: S402. When the battery is in the plateau region and is being charged or discharged, or when the battery is in the charging state and the maximum voltage value of the battery cell exceeds the preset charging end voltage threshold: Judge whether the voltage difference between the current battery cell and the reference battery cell is greater than the preset voltage difference. If so, determine that the current battery cell is the battery cell that needs to be balanced; if not, the current battery cell does not need to be balanced; Among them, the preset charging end voltage threshold is obtained by referring to the voltage table corresponding to 95% SOC at different charging rates and temperatures.

[0060] It can be known that when the battery is at the end of charging or in the dynamic state of the plateau region, the battery cells that need to be balanced can be determined by judging the voltage difference between the current battery cell and the reference battery cell.

[0061] In the actual operation of this embodiment, referring to Figure 4 , in step S5, the method for balancing control of the battery cells that need to be balanced based on the balancing time or the balancing voltage difference includes the following steps: S501: When the battery is in the low SOC static state or the low SOC dynamic working condition, perform balancing control on the battery cells based on the balancing time; Exemplarily, the formula for calculating the balancing time of the battery cells that need to be balanced is: balancing time = (△SOC - 1) × rated capacity × SOH / balancing current.

[0062] S502: When the battery is in the dynamic state of the plateau region or the end of charging working condition, perform balancing control on the battery cells based on the balancing voltage difference until the balancing voltage difference is less than or equal to the preset value; Among them, the balancing voltage difference is the voltage difference between the current battery cell and the reference battery cell.

[0063] It should be noted that when the battery is in a low SOC static state or a low SOC dynamic condition, the battery cells can be balanced according to the calculated balancing time; while when the battery is in a plateau dynamic or end-of-charge condition, the battery cells are balanced until the voltage difference from the reference cell reaches a reasonable range.

[0064] Therefore, different balancing strategies are adopted for different working conditions, so as to effectively improve the balancing efficiency on the premise of ensuring the balancing effect, which can meet the requirements of battery balancing.

[0065] Exemplarily, the above-mentioned balancing control strategy can also be adjusted according to the actual situation of the battery, and no specific limitation is made in this embodiment.

[0066] In actual operation of this embodiment, referring to Figure 4 , in step S5, the step of balancing the battery cells to be balanced based on the balancing time or the balancing voltage difference further includes the following steps: S503: After balancing the battery cells to be balanced, output the balancing capacity values of each battery cell, which are used as the basis for determining the reference cell.

[0067] It is not difficult to see that in step S503, after balancing the battery cells to be balanced, by outputting the balancing capacity of each battery cell, it is convenient to use this as the basis for determining the reference cell in step S2.

[0068] Based on the same inventive concept, an embodiment of the present application also provides a battery balancing control device. Since the principle of solving problems by the device in the embodiment of the present application is similar to that of the above-mentioned battery balancing control method in the embodiment of the present application, the implementation of the device can refer to the implementation of the method, and the repeated parts will not be elaborated.

[0069] Referring to Figure 4 , this embodiment also proposes a battery balancing control device applied to the above battery balancing control method, including: An information acquisition module, configured to acquire the state information of the battery in real time and count the balancing capacity of each balanced battery cell; wherein, the battery includes at least one battery cell, and the state information includes at least current information, voltage information of the battery cell, and temperature information; An information processing module, configured to estimate the capacity and internal resistance of the battery cell according to the state information, and eliminate abnormal battery cells based on the estimated capacity, internal resistance of the battery cell, and the acquired balancing capacity of each balanced battery cell, and determine the reference cell; An information operation module, configured to compare each battery cell with the reference cell based on the battery working condition, determine the battery cells to be balanced, and calculate the balancing time and balancing voltage difference of the battery cells to be balanced; The balancing control module is used to perform balancing control on the battery cells that need to be balanced according to the balancing time and the balancing pressure difference, and output the balancing capacity values of each battery cell.

[0070] It can be known that a battery balancing control device described in this embodiment collects and obtains battery state information in real time through an information acquisition module, and uses an information processing module to estimate the capacity and internal resistance of the battery cells and count the balancing of the battery cells after balancing, which is convenient for excluding abnormal battery cells according to the actual situation, thus avoiding wrong balancing as much as possible, eliminating the interference of capacity-abnormal battery cells on the balancing control, and then improving the accuracy of the balancing control; in addition, by determining the reference battery cell, a comparison basis is also provided for determining the battery cells to be balanced; by using an identification and judgment module to judge the working condition state of the battery, it is convenient to determine the battery cells that need to be balanced and formulate different balancing control strategies according to different working conditions. Through the working condition division of low SOC static, low SOC dynamic, platform area dynamic and end-of-charge, the execution efficiency of battery capacity balancing is improved on the premise of covering most working conditions, and the balancing control module performs balancing control on the battery cells that need to be balanced, which can meet the balancing control requirements of the battery.

[0071] In some embodiments, the information processing module estimates the capacity of each battery cell as follows: when the capacity of continuous charging or discharging exceeds a preset value, the capacity of each battery cell is estimated by Qall = △Q / △SOC; where Qall is the capacity of all battery cells, △Q is the capacity of continuous charging or discharging, and △SOC is the SOC change value of each battery cell.

[0072] In some embodiments, the information processing module excludes abnormal battery cells according to the estimated capacity of the battery cells, including: comparing the estimated capacity of each battery cell with the current capacity of the battery cell, and when the ratio of the estimated capacity of the battery cell to the current capacity of the battery cell is less than a preset value, excluding the battery cell that cannot be used as a reference battery cell, where the current capacity of the battery cell = the rated capacity of the battery cell × SOH.

[0073] Specifically, when the ratio of the estimated capacity of the battery cell to the current capacity of the battery cell is less than 95%, the battery cell is excluded and cannot be used as a reference battery cell.

[0074] In some embodiments, the internal resistance of the battery cells is estimated by estimating the internal resistance of the battery cell with the maximum single-cell voltage, the internal resistance of the battery cell with the minimum single-cell voltage, and the internal resistance of the battery cell with the average single-cell voltage respectively.

[0075] Exemplarily, the method for the information processing module to estimate the internal resistance of each battery cell is to jointly estimate the SOC of the battery cell and the ohmic internal resistance R0, and combine the second-order RC circuit model. After model discretization, the following equation is obtained to estimate the ohmic internal resistance R0 of the battery cell:

[0076] In some embodiments, the method for the information processing module to eliminate abnormal battery cells according to the estimated internal resistance of the battery cells includes the following steps: Compare the internal resistance of the battery cell with the maximum estimated single-cell voltage with the internal resistance of the battery cell with the minimum single-cell voltage; When the ratio of the internal resistance of the battery cell with the maximum single-cell voltage to the internal resistance of the battery cell with the minimum single-cell voltage is greater than a preset value, the battery cell with the maximum single-cell voltage cannot be used as a reference battery cell and is eliminated.

[0077] In some embodiments, the method for the information acquisition module to count the equalization capacity of each equalized battery cell includes the following steps: Determine whether there are equalized battery cells in the battery. If so, obtain the equalization capacity of each equalized battery cell and use it as the basis for eliminating the reference battery cell.

[0078] In some embodiments, the method for the information processing module to eliminate abnormal battery cells according to the obtained equalization capacity of each equalized battery cell includes the following steps: When the statistics of the equalization capacity of each battery cell reach a preset time, remove the battery cell with the minimum equalization capacity, and compare the equalization capacity of each remaining battery cell with the average equalization capacity; When there is a battery cell among the remaining battery cells whose ratio of the equalization capacity to the average equalization capacity is less than a preset value, the battery cell cannot be used as a reference battery cell and is eliminated; Wherein, the average equalization capacity is the average value of the equalization capacities of the remaining other battery cells after removing the battery cell with the minimum equalization capacity and the battery cell with the maximum equalization capacity.

[0079] In some embodiments, the method for the information operation module to determine the battery cells that need to be equalized based on the battery working conditions includes the following steps: When the battery is in a low SOC state and stands still for a preset low-end standing time, or when the battery is in a low SOC state and undergoes dynamic charge and discharge, compare the SOC value of the current battery cell with the SOC value of the reference battery cell to determine the battery cells that need to be equalized; Wherein, the preset low-end standing time is configured as the time during which the voltage of the battery cell remains unchanged during the standing process corresponding to different temperatures. When the battery is in a low SOC state and stands still until the preset low-end standing time is satisfied, the SOC value of the current battery cell is obtained by looking up the OCV-SOC table according to the voltage of the battery cell.

[0080] When the battery is in a low SOC state and undergoes dynamic charge and discharge, calculate the SOC value of the current battery cell through the following formula: SOCmin + (SOCmax - SOCmin) / (Vmax - Vmin) × (V - Vmin); Wherein, SOCmin and SOCmax respectively represent the minimum SOC and the maximum SOC in each battery cell, Vmax and Vmin respectively represent the maximum battery cell voltage and the minimum battery cell voltage, and V represents the voltage of any one battery cell.

[0081] Specifically, when the difference between the SOC of the current battery cell and the SOC of the reference battery cell is greater than 1%, it is determined that the current battery cell is a battery cell that needs to be balanced; otherwise, the current battery cell does not need to be balanced.

[0082] In some embodiments, the information operation module determines the battery cells that need to be balanced based on the battery working conditions, and further includes the following steps: When the battery is in the plateau region and is charging or discharging, or when the battery is in the charging state and the maximum voltage value of the battery cell exceeds the preset charging end voltage threshold: Judge whether the voltage difference between the current battery cell and the reference battery cell is greater than the preset voltage difference. If so, determine that the current battery cell is a battery cell that needs to be balanced; if not, the current battery cell does not need to be balanced; In some embodiments, the balancing control module performs balancing control on the battery cells that need to be balanced based on the balancing time or the balancing voltage difference, and includes the following steps: When the battery is in the low SOC static or low SOC dynamic working condition, perform balancing control on the battery cells based on the balancing time; Specifically, when the battery is in the low SOC state and stands still until the preset low-end standing time is met, or when the battery is in the low SOC state and is dynamically charged or discharged, the formula for calculating the balancing time of the battery cells that need to be balanced is: Balancing time = (△SOC - 1) × rated capacity × SOH / balancing current.

[0083] When the battery is in the plateau region dynamic or charging end working condition, perform balancing control on the battery cells based on the balancing voltage difference until the balancing voltage difference is less than or equal to the preset value; Wherein, the balancing voltage difference is the voltage difference between the current battery cell and the reference battery cell.

[0084] It further includes: after performing balancing control on the battery cells that need to be balanced, output the balancing capacity values of each battery cell, and use this as the basis for determining the reference battery cell.

[0085] Based on the same inventive concept of the present invention, referring to Figure 6 , this embodiment further provides an electronic device, including: a processor, and a memory connected to the processor; the memory is used to store a computer program; the processor is used to call and execute the computer program in the memory to execute the steps of the battery balancing control method as described above.

[0086] In actual operation of this embodiment, referring to Figure 6, the electronic device includes: a processor, a memory, a bus, and a communication interface, where the processor, the communication interface, and the memory are connected through the bus; the processor is configured to execute an executable module stored in the memory, such as a computer program; specifically, the memory is used to store programs, and the processor executes the programs after receiving an execution instruction. The method executed by the device in the foregoing embodiments can be applied to the processor or implemented by the processor.

[0087] Exemplarily, the memory may include a high-speed random access memory (RAM), and may also include a non-volatile memory, such as at least one disk memory. The communication connection between the system network element and at least one other network element is implemented through at least one communication interface (which can be wired or wireless). The Internet, wide area network, local area network, metropolitan area network, etc. can be used.

[0088] Furthermore, the bus can be an ISA bus, a PCI bus, an EISA bus, etc. The bus can be divided into an address bus, a data bus, a control bus, etc. For the sake of convenience of representation, Figure 6 only a bidirectional arrow is used in the figure, but it does not mean that there is only one bus or one type of bus.

[0089] Even further, the processor may be an integrated circuit chip with signal processing capabilities; in the implementation process, each step of the above method can be completed by the integrated logic circuit in the hardware of the processor or the instructions in the form of software.

[0090] Specifically, the above-mentioned processor can be a general-purpose processor, including a central processing unit (CPU), a network processor (NP), etc., and can also be a digital signal processor (DSP), an application-specific integrated circuit (referred to as ASIC), a field-programmable gate array (referred to as FPGA) or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, and can implement or execute the various methods, steps, and logic block diagrams disclosed in the embodiments of the present invention.

[0091] In the embodiments of the present application, by invoking the programs or instructions stored in the memory, the processor is configured to execute the steps in a battery equalization control method. Through software, the accuracy and execution efficiency of battery equalization control can be improved for the battery equalization strategy.

[0092] This embodiment is an embodiment of a storage medium provided by the present invention. A computer program is stored on the storage medium, and when the computer program is executed by the processor, the steps of the above-mentioned battery equalization control method are implemented.

[0093] The computer program product of the storage medium provided by the embodiments of the present invention includes a computer-readable storage medium storing program code, and the instructions included in the program code can be used to execute the battery balancing control method described in the foregoing method embodiments.

[0094] The steps of the method disclosed in the embodiments of the present invention can be directly embodied as being executed and completed by a hardware decoding processor, or can be executed and completed by a combination of hardware and software modules in the decoding processor; the software module can be located in a mature storage medium in the art such as a random access memory, a flash memory, a read-only memory, a programmable read-only memory, or an electrically erasable programmable memory, a register, etc. This storage medium is located in the memory, and the processor reads the information in the memory and combines its hardware to complete the steps of the foregoing method.

[0095] If the method described in the embodiments of the present invention is implemented in the form of a software functional module and sold or used as an independent product, it can be stored in a computer-readable storage medium; based on such an understanding, the technical solution of the present invention essentially or the part that contributes to the prior art can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions for causing a computer device (which can be a personal computer, a server, or a network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of the present invention.

[0096] Exemplarily, the storage medium package can be various media that can store program code, such as a USB flash drive, a mobile hard disk, a read-only memory (ROM), a random access memory (RAM), a magnetic disk, or an optical disc.

[0097] The above has introduced in detail a battery balancing control method, device, electronic device, and storage medium provided by the present application; specific examples are used in this article to elaborate on the principle and implementation manner of the present application. The description of the above embodiments is only used to help understand the method and its core idea of the present application; it should be noted that for those of ordinary skill in the art of the present technology, without departing from the principle of the present application, several improvements and modifications can still be made to the present application, and these improvements and modifications also fall within the protection scope of the claims of the present application.

Claims

1. A battery balancing control method, characterized in that The method includes the following steps: Obtain the state information of the battery, where the battery includes at least one battery cell, and the state information includes current information, voltage information of the battery cell, and temperature information; Estimate the capacity and internal resistance of the battery cell according to the state information, and obtain the balanced capacity of each battery cell after balancing; Eliminate abnormal battery cells according to the estimated capacity and internal resistance of the battery cell and the balanced capacity of each battery cell after obtaining the balance, and determine the battery cell with the minimum voltage among the remaining battery cells as the reference battery cell; Based on the working condition of the battery, compare each battery cell with the reference battery cell to determine the battery cells that need to be balanced; According to the working condition of the battery, calculate the balancing time or balancing voltage difference of the battery cells that need to be balanced, and perform balancing control on the battery cells that need to be balanced based on the balancing time or balancing voltage difference; Among them, the working condition includes at least one of low SOC static, low SOC dynamic, platform area dynamic, and end-of-charge.

2. The battery equalization control method according to claim 1, wherein The method for estimating the capacity of the battery cell includes the following steps: When the capacity of continuous charging or discharging exceeds a preset value, estimate the capacity of each battery cell by Qall = △Q / △SOC; Among them, Qall is the capacity of all battery cells, △Q is the capacity of continuous charging or discharging, and △SOC is the SOC change value of each battery cell.

3. A battery balancing control method according to claim 1 or 2, characterized in that The method for eliminating abnormal battery cells according to the estimated capacity of the battery cell includes the following steps: Compare the estimated capacity of the battery cell with the current capacity of the battery cell. When the ratio of the estimated capacity of the battery cell to the current capacity of the battery cell is less than the preset value, eliminate this battery cell and it cannot be used as the reference battery cell, where the current capacity of the battery cell = rated capacity of the battery cell × SOH.

4. The battery balancing control method according to claim 3, characterized in that, When the ratio of the estimated capacity of the battery cell to the current capacity of the battery cell is less than 95%, eliminate this battery cell and it cannot be used as the reference battery cell.

5. A battery equalization control method according to claim 1, characterized in that, The estimation of the internal resistance of the battery cell includes respectively estimating the internal resistance of the battery cell with the maximum single-cell voltage, the internal resistance of the battery cell with the minimum single-cell voltage, and the internal resistance of the battery cell with the average single-cell voltage.

6. The battery equalization control method according to claim 5, characterized in that The method for estimating the internal resistance of the battery cell includes the following steps: Jointly estimate the SOC of the battery cell and the ohmic internal resistance R0, and combine the second-order RC circuit model. After model discretization, the following equation is obtained: And estimate the ohmic internal resistance R0 of the battery cell according to the above formula.

7. A battery balancing control method according to claim 5 or 6, characterized in that, The method for eliminating abnormal battery cells according to the estimated internal resistance of the battery cell includes the following steps: Compare the internal resistance of the battery cell with the maximum single-cell voltage estimated with the internal resistance of the battery cell with the minimum single-cell voltage; When the ratio of the internal resistance of the battery cell with the maximum single-cell voltage to the internal resistance of the battery cell with the minimum single-cell voltage is greater than the preset value, eliminate the battery cell with the maximum single-cell voltage and it cannot be used as the reference battery cell.

8. A battery balancing control method according to claim 1, characterized in that, The method for obtaining the balanced capacity of each battery cell after balancing includes the following steps: Judge whether there are battery cells after balancing in the battery. If so, obtain the balanced capacity of each battery cell after balancing and use it as the basis for eliminating the reference battery cell.

9. A battery equalization control method according to claim 8, characterized in that, The method for eliminating abnormal battery cells according to the obtained balanced capacity of each battery cell after balancing includes the following steps: When the statistical accumulation of the balanced capacity of each battery cell reaches the preset time, remove the battery cell with the minimum balanced capacity, and compare the balanced capacity of each battery cell among the remaining battery cells with the average balanced capacity; When there is a cell in the remaining cells whose ratio of the equalization capacity to the average equalization capacity is less than a preset value, this cell cannot be removed as a reference cell; Wherein, the average equalization capacity is the average value of the equalization capacities of the remaining other cells after removing the cell with the minimum equalization capacity and the cell with the maximum equalization capacity.

10. A battery equalization control method according to claim 1, characterized in that, The determining of the cells to be equalized based on the battery operating conditions includes the following steps: When the battery is in a low SOC state and stands still for a preset low-end standing time, or when the battery is in a low SOC state and undergoes dynamic charge and discharge, compare the SOC value of the current cell with the SOC value of the reference cell to determine the cells to be equalized; Wherein, the preset low-end standing time is configured as the time during which the voltage of the cell remains unchanged during the standing process corresponding to different temperatures.

11. A battery equalization control method according to claim 10, wherein When the battery is in a low SOC state and stands still until it meets the preset low-end standing time, obtain the SOC value of the current cell by looking up the OCV-SOC table according to the voltage of the cell, When the battery is in a low SOC state and undergoes dynamic charge and discharge, calculate the SOC value of the current cell through the following formula: SOCmin + (SOCmax - SOCmin) / (Vmax - Vmin) × (V - Vmin); Wherein, SOCmin and SOCmax respectively represent the minimum SOC and the maximum SOC in each cell, Vmax and Vmin respectively represent the maximum cell voltage and the minimum cell voltage, and V represents the voltage of any one cell.

12. A battery equalization control method according to claim 10, characterized in that The comparing the SOC value of the current cell with the SOC value of the reference cell to determine the cells to be equalized includes the following steps: When the difference between the SOC of the current cell and the SOC of the reference cell is greater than 1%, determine that the current cell is a cell to be equalized; otherwise, this current cell does not need to be equalized.

13. A battery equalization control method according to claim 1, characterized in that The determining of the cells to be equalized based on the battery operating conditions further includes the following steps: When the battery is in the plateau region and undergoes charge and discharge, or when the battery is in the charging state and the maximum voltage value of the cell exceeds the preset charging end-stage voltage threshold: Judge whether the voltage difference between the current cell and the reference cell is greater than the preset voltage difference. If so, determine that the current cell is a cell to be equalized; if not, the current cell does not need to be equalized; Wherein, the preset charging end-stage voltage threshold is obtained by looking up the voltage table corresponding to 95% SOC according to different charging rates and temperatures.

14. A battery equalization control method according to any one of claims 1-13, characterized in that The equalization control of the cells to be equalized based on the equalization time or the equalization voltage difference includes the following steps: When the battery is in a low SOC standing or low SOC dynamic condition, perform equalization control on the cells based on the equalization time; When the battery is in the plateau region dynamic or charging end-stage condition, perform equalization control on the cells based on the equalization voltage difference until the equalization voltage difference is less than or equal to the preset value; Wherein, the equalization voltage difference is the voltage difference between the current cell and the reference cell.

15. A battery equalization control method according to claim 14, characterized in that, When the battery is in a low SOC state and has been static for a preset low-end static time, or when the battery is in a low SOC state and is undergoing dynamic charge and discharge, the formula for calculating the equalization time of the cells that need to be equalized is: Equalization time = (△SOC - 1) × Rated capacity × SOH / Equalization current.

16. A battery equalization control method according to claim 14, characterized in that, After performing equalization control on the cells that need to be equalized, the following steps are also included: Output the equalization capacity values of each cell, which serve as the basis for determining the reference cell.

17. A battery balancing control device is applied to the battery balancing control method as described in claims 1-16, and is characterized in that, Including: An information acquisition module for real-time obtaining the state information of the battery and statistically calculating the equalization capacity of each equalized cell; wherein, the battery includes at least one cell, and the state information includes at least current information, voltage information of the cell, and temperature information; An information processing module for estimating the cell capacity and internal resistance based on the state information, and removing abnormal cells and determining the reference cell based on the estimated cell capacity and internal resistance and the obtained equalization capacity of each equalized cell; An information operation module for comparing each cell with the reference cell based on the battery operating conditions, determining the cells that need to be equalized, and calculating the equalization time and equalization voltage difference of the cells that need to be equalized; An equalization control module for performing equalization control on the cells that need to be equalized according to the equalization time and equalization voltage difference, and outputting the equalization capacity values of each cell.

18. An electronic device, characterized in that, Including: A processor and a memory connected to the processor; The memory is used for storing computer programs; The processor is used for calling and executing the computer program in the memory to perform the steps of the battery equalization control method as described in any one of claims 1 to 16.

19. A computer-readable storage medium, characterized in that, A computer program is stored on this computer-readable storage medium, and when the computer program is run by the processor, it performs the steps of the battery equalization control method as described in any one of claims 1 - 16.

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