Method and system for equalizing the state of charge of a battery

Abstract

The present application relates to a method and system for balancing the battery SOC of a battery system of an electric vehicle, and a vehicle having the balancing system. The method includes determining the single-cell SOC data of a plurality of single-cell batteries based on the voltages of the plurality of single-cell batteries obtained, determining the intra-module balancing target SOC data of each battery module based on the single-cell SOC data, determining the inter-module balancing target SOC data of the battery system based on the intra-module balancing target SOC data and the single-cell SOC data, and determining the SOC balancing strategy for the battery system based on the inter-module balancing target SOC data, the intra-module balancing target SOC data and the single-cell SOC data. The above solution does not require complex changes to the balancing system components of the battery system, and introduces the SOC balancing strategy of the battery module to achieve high-speed, efficient and cost-effective battery balancing control.

Description

Technical Field

[0001] The present application relates to battery control, and more particularly, to a method and system for balancing the state of charge (SOC) of batteries of a battery system, and a vehicle having the balancing system, in particular an electric vehicle driven by power from the battery system. Background Art

[0002] As electric vehicles become increasingly popular, the requirements for controlling their power battery systems are becoming increasingly stringent. Limited by the state of battery manufacturing technology, the power capacity and voltage of single lithium-ion batteries cannot meet the actual performance requirements of electric vehicles. Therefore, combining single cells in series and parallel to form battery modules to construct power battery systems has become an effective way to use lithium-ion batteries to meet the high-power and high-energy power source requirements.

[0003] However, battery system performance is significantly impacted by cell consistency. Cell consistency refers to the degree of variation in voltage, internal resistance, capacity, and other parameters between individual cells of the same specifications and model. Excessive cell consistency, or inconsistency between cells, directly impacts the electrical performance of the entire battery system, which in turn affects the electric vehicle's power, range, and service life. Cell inconsistency tends to worsen over time.

[0004] Battery systems require balancing to control inconsistencies between individual cells, particularly the battery's SOC. Existing balancing solutions typically compare each cell's SOC with a target SOC to determine whether to charge or discharge the battery. This results in high costs and low efficiency. Therefore, there is a need for improved balancing solutions for battery systems. Summary of the Invention

[0005] Embodiments of the present application provide a method and system for balancing the state of charge (SOC) of batteries in a battery system of an electric vehicle, as well as a vehicle having the balancing system, so as to overcome the shortcomings of existing balancing solutions and provide a faster, more efficient and cost-effective battery balancing control strategy.

[0006] According to one aspect of the present application, a method for balancing the state of charge (SOC) of batteries in a battery system is provided. The battery system includes a plurality of battery modules, each of which includes a plurality of single cells. The method includes:

[0007] determining cell SOC data of the plurality of cell batteries based on the acquired voltages of the plurality of cell batteries, the cell SOC data including a cell SOC of each cell battery;

[0008] Determine the intra-module balancing target SOC data of each battery module based on the single cell SOC data;

[0009] Determining inter-module balancing target SOC data of the battery system based on the intra-module balancing target SOC data and the cell SOC data; and

[0010] The SOC balancing strategy for the battery system is determined based on the inter-module balancing target SOC data, the intra-module balancing target SOC data and the single cell SOC data.

[0011] According to another aspect of the present application, a system for balancing the state of charge (SOC) of batteries in a battery system is provided. The battery system includes a plurality of battery modules, each of which includes a plurality of single cells. The device includes:

[0012] A voltage acquisition module configured to acquire the voltage of a single battery;

[0013] A single cell passive balancing module, which corresponds to each single cell and is configured to perform passive balancing discharge on the single cell;

[0014] A battery module passive balancing module, which corresponds to each battery module and is configured to perform passive balancing discharge on the battery module;

[0015] a single cell selection module configured to select a single cell to be charged or discharged;

[0016] a reversing module connected to the battery system and configured to charge or discharge the single cells and / or battery modules; and

[0017] The controller is configured to control the voltage acquisition module, the single cell passive balancing module, the battery module passive balancing module, the single cell selection module and the commutation module connected thereto to balance the state of charge (SOC).

[0018] According to another aspect of the present application, an electric vehicle is provided, comprising a battery system including a plurality of battery modules, each battery module including a plurality of single cells; and the system for balancing the state of charge (SOC) of batteries of the battery system as described above.

[0019] According to another aspect of the present application, a computer-readable storage medium is provided, on which a computer program including executable instructions is stored. When the executable instructions are executed by a processor, the processor is caused to implement the method described above.

[0020] By adopting the battery SOC balancing solution proposed in this application, the SOC balancing strategy of the battery module can be introduced on the basis of the vehicle external charger balancing system without making complex changes to the balancing system components of the battery system, thereby simplifying the battery SOC balancing process for each single cell in the battery system. The battery characteristic analysis and battery SOC balancing can be completed in the shortest time, reducing the performance impact of the battery system caused by battery inconsistency, improving the power performance and cruising range of the battery system, and increasing the service life of the battery system, thereby achieving high-speed, efficient and cost-effective battery balancing control.

[0021] It should be understood that the above general description and the following detailed description are merely exemplary and explanatory and do not limit the scope of protection of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The above and other features and advantages of the present application will become more apparent by describing in detail exemplary embodiments thereof with reference to the attached drawings.

[0023] Figure 1 is a schematic block diagram of a system for balancing the SOC of batteries in a battery system according to an embodiment of the present application;

[0024] Figure 2 is a schematic logic block diagram of an equalization algorithm for equalizing the battery SOC of a battery system according to an embodiment of the present application;

[0025] Figure 3 is a schematic flow chart of a method for balancing the battery SOC of a battery system according to an embodiment of the present application; and

[0026] Figure 4 4 is a schematic block diagram of an electronic device for balancing the SOC of batteries in a battery system according to an embodiment of the present application. DETAILED DESCRIPTION

[0027] The exemplary embodiments will now be described more fully with reference to the accompanying drawings. However, the exemplary embodiments can be implemented in many forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this application will be thorough and complete and will fully convey the concepts of the exemplary embodiments to those skilled in the art. In the drawings, the dimensions of some elements may be exaggerated or distorted for clarity. Identical reference numerals in the drawings represent identical or similar structures, and thus their detailed description will be omitted.

[0028] In addition, described feature, structure or characteristic can be combined in one or more embodiments in any suitable manner.In the following description, many specific details are provided so as to provide a full understanding of the embodiments of the present application. However, it will be appreciated by those skilled in the art that the technical scheme of the present application can be put into practice without one or more of the specific details, or other methods, elements, etc. can be adopted. In other cases, known structures, methods or operations are not shown or described in detail to avoid blurring the various aspects of the application.

[0029] In this application, battery balancing can be understood as equalizing the state of charge (SOC) between batteries (especially single cells), controlling the SOC of the single cells to the same level. SOC is usually expressed as a percentage, indicating the ratio of the current charge of the battery to the rated (charge) capacity of the battery.

[0030] The SOC of a battery can be calculated by the voltage (potential difference) between the positive and negative terminals of the battery. The inconsistency of the battery leads to different SOCs between different batteries, which is reflected in the different voltages between the positive and negative terminals of the battery. If the battery voltage is in an unbalanced state, when charging multiple single cells in the battery module of the battery system, it is possible that one / some single cells in the series battery module reach the rated voltage and charging stops, but at this time the other single cells in the series battery module are not fully charged and cannot continue to charge. In the absence of battery SOC balancing control, the SOC of the battery system during charging is theoretically calculated based on the highest single cell SOC (via voltage or rated voltage), but in fact not all single cells in the battery system reach this theoretical voltage value, which reduces the performance of the battery system, the driving range and the battery life. During discharge, if the SOC of one or more cells in a series battery module is depleted, the voltage of the battery module or battery system will drop, making it unable to continue discharging to provide the required power. At this time, other cells may still have residual SOC, wasting energy, or discharging according to the cell with the highest SOC may cause cells with lower SOC to be over-discharged, shortening their lifespan. Therefore, during discharge, calculations are usually made based on the cell with the lowest SOC (via voltage) in the battery system / battery module.

[0031] The goal of battery balancing is to control the SOC of individual cells to the same level, that is, to achieve the target SOC for balancing. Existing battery SOC balancing systems based on external chargers only determine whether SOC balancing is necessary based on the SOC of individual cells, and do not consider SOC balancing operations for battery modules. According to embodiments of the present application, for individual cells or battery modules whose SOC is higher than the target SOC for balancing, the SOC can be reduced to the target SOC for balancing by discharging the individual cells or battery modules (via at least one cell in the battery module). For individual cells or battery modules whose SOC is higher than the target SOC for balancing, the SOC can be increased to the target SOC for balancing by charging the individual cells or battery modules (via at least one cell in the battery module). Discharging and charging for balancing purposes are also referred to as passive balancing discharge and active balancing charge, respectively. Passive balancing discharge can transfer charge from individual cells with an SOC higher than the target SOC for balancing; active balancing charge can replenish charge in cells with an SOC lower than the target SOC.

[0032] It can be seen that balancing the single cells in the battery system can effectively alleviate the impact of inconsistencies between cells on the performance and life of the battery system.

[0033] Figure 1 FIG. 1 is a schematic structural block diagram of a balancing system 100 for balancing battery SOC in a battery system.

[0034] The battery system includes a plurality of battery modules 110 (in Figure 1 Each battery module 110 includes a plurality of single cells, such as single cells 101, 102, 103, and 104. These single cells are of the same specification and model, and have the same rated voltage, rated internal resistance, and rated capacity.

[0035] The balancing system 100 primarily includes a voltage acquisition module 120, a single-cell passive balancing module 130, a battery module passive balancing module 140, a single-cell selection module 150, a switching module 160, and a controller 170. Controller 170 is signal-connected to each of these modules 130-160. Based on an external charger 180 with a high-power resistor, the balancing system 100 analyzes the voltage changes of the single cells 101-104 to determine whether the electric vehicle's power battery requires balancing control. It then employs a corresponding balancing strategy to control the battery system's SOC balancing process.

[0036] The voltage acquisition module 120 includes multiple voltage sensors corresponding to the cells 101-104, and is used to acquire the voltage of each cell in real time, that is, the potential difference between the positive and negative electrode terminals of the battery. The voltage acquisition module 120 is connected to the controller 170 to provide the acquired cell voltages to the controller 170, so that the cell SOC of the cell can be determined based on the cell voltages. The cell SOC of all cells constitutes the cell SOC data of the battery system.

[0037] The cell passive balancing module 130 includes multiple passive balancing circuits 131, 132, 133, and 134, corresponding to the cells 101-104 and connected in parallel with each cell, for passively balancing and discharging each cell. Each passive balancing circuit 131-134 consists of a controlled switching element (e.g., MOS transistor 131a in circuit 131) and a cell passive balancing resistor (e.g., resistor 131b in circuit 131). Taking passive balancing circuit 131 as an example, controlled switching element 131a, under the control of controller 170, turns passive balancing circuit 131 on and off to achieve passive balancing discharge of cell 101. Controlled switching elements can take various forms, such as transistors (BJTs), field-effect transistors (MOS transistors), and relays. The following describes the function of controlled switching elements using a MOS transistor, which receives a controlled signal through its gate, as an example. The cell passive balancing resistor and the cell's internal resistance determine the cell's passive balancing discharge rate. For single cells of the same model, the passive balancing resistors of the single cells can be set to have the same resistance value.

[0038] The battery module passive balancing module 140 includes a plurality of passive balancing circuits corresponding to the battery modules 110 and connected in parallel with each battery module. The battery module passive balancing module 140 can increase the inter-module balancing control strategy set by the controller 170 at the battery module level, improve the efficiency of the SOC balancing control of the battery system, and achieve the optimal SOC balancing control improvement by increasing the component cost to a minimum. Figure 1In the figure, only one passive balancing circuit corresponding to battery module 110 is shown. However, those skilled in the art will understand that this illustration is merely an example and does not limit the number of passive balancing circuits in battery module passive balancing module 140. The passive balancing circuit corresponding to battery module 110 is used to perform inter-module passive balancing discharge on the battery module 110 and includes a MOS transistor 141 and a battery module passive balancing resistor 142. Under the control of controller 170, MOS transistor 141 turns the passive balancing circuit on or off to achieve inter-module passive balancing discharge on the battery module 110. The passive balancing resistor 142 and the internal resistance of the individual cells within the battery module determine the passive balancing discharge rate of the battery module 110. Inter-module passive balancing discharge of the battery module 110 is achieved by performing passive balancing discharge on at least one individual cell within the battery module as a whole.

[0039] The single cell selection module 150 includes a plurality of single cell selection circuits corresponding to each single cell and connected in series between the positive electrode of the single cell and the power input / output terminal, for selecting a single cell to be charged or discharged. Figure 1 As shown in FIG, five cell selection circuits are connected in series between the two ends of each cell 101-104 and the reversing module 160. In a battery module, because the positive and negative electrode terminals of two adjacent cells are connected in series and share a cell selection circuit, the number of cell selection circuits exceeds the number of cells in the battery module by one. Each cell selection circuit includes two MOS transistors (or relays) connected in reverse series. Two diodes with opposite polarities are connected in parallel to the two MOS transistors to control the direction of current flow. Under the control of the controller 170, the two MOS transistors are switched on and off, respectively, to close the current path in a specific direction, using the current from the external charger 180 to charge the selected cell or output power from the cell. The bidirectional conduction configuration of the cell selection circuit also provides isolation protection.

[0040] The reversing module 160 is disposed between the single cell selection module 150 and the external charger 180, and selects a specific combination of single cells or battery modules for charging or discharging through the multiple reversing circuits it includes. Similar to the single cell selection circuit in the single cell selection module 150, the reversing circuit in the reversing module 160 includes two MOS tubes (or relays) connected in reverse series, and the two MOS tubes are respectively connected in parallel with two diodes of opposite polarity to control the direction of the current. Under the control of the controller 170, the two MOS tubes are respectively in the on and off states to close the current path in a specific direction, thereby charging and / or discharging the selected single cell and / or battery module combination. By different connection combinations of the reversing circuit and the single cell / battery module, the charging / discharging strategy of different parts of the battery system can be implemented.

[0041] The controller 170 is used to receive the single cell voltage from the voltage acquisition module 120, determine the single cell SOC of each single cell based on the obtained single cell voltage, use the SOC balancing algorithm to calculate the intra-module balancing target SOC data of each battery module based on the single cell SOC data, calculate the inter-module balancing target SOC data, and then determine the SOC balancing strategy for the battery system, and send control instructions to at least one controlled switching element in the single cell passive balancing module 130, the battery module passive balancing module 140, the single cell selection module 150 and / or the reversing module 160 to control the conduction and shutdown of the corresponding circuit to achieve SOC balancing of the battery system.

[0042] The following combination Figure 2 The schematic logic flow of the balancing algorithm for balancing the SOC of the batteries of the battery system is shown to introduce the SOC balancing control process implemented in the controller 170 .

[0043] After the battery system is activated, the controller 170 of the balancing system 100 begins monitoring the SOC information of each battery cell in the battery system. At block 201, the controller 170 receives the voltage of each battery cell (such as batteries 101-104) collected in real time by the voltage acquisition module 120. Then, at block 202, the controller 170 estimates and determines the SOC of each battery cell.

[0044] At decision 203, the system 100 checks whether there is a start-up instruction to implement the SOC balancing control function. If there is a start-up instruction, further operation is performed, otherwise no further operation is performed and the battery system is continuously monitored. According to an embodiment of the present application, the controller 170 can generate SOC balancing status information of the battery system based on the single cell SOC data of the monitored single cell. The user of the vehicle, the on-board control system or the vehicle manufacturer can decide whether to turn on the SOC balancing control function locally or remotely in the vehicle based on the SOC balancing status information, and issue a start-up instruction when necessary. The SOC balancing control function can be started after the vehicle has traveled a certain mileage or periodically to keep the vehicle's battery system in a healthy and controllable SOC consistency state.

[0045] When the SOC balancing control function is enabled, the system calculates the intra-module balancing target SOC and inter-module balancing target SOC data of each battery module of the battery system for the specified SOC balancing strategy at block 204 .

[0046] Specifically, the calculation process of the balanced target SOC within the module is as follows:

[0047] For each battery module (e.g., battery module 110), the maximum single-cell SOC, SOC max , and minimum SOC, SOC min The monomer SOC interval [SOC max , SOC min ] arbitrarily select n different SOC values as the target SOC for the candidate module to be balanced. Ei , where i = 1, 2, 3, ..., n; SOC max , SOC min and SOC Ei The unit is %.

[0048] Next, we need to balance the target SOC from these candidate modules. Ei The candidate intra-module balancing target SOC that minimizes the SOC balancing time of the battery module is selected as the optimal intra-module balancing target SOC of the battery module. The number n of enumerations is independent of the number of cells in the battery module. The larger its value (the denser the selection in the cell SOC range), the more accurate the calculated optimal intra-module balancing target SOC. For example, SOC Ei It can be calculated by formula (1), where n SOCs are uniformly selected at the same interval in the single SOC interval. Ei .

[0049]

[0050] For each selected SOC Ei , respectively calculate the total module balancing time used to balance the SOC of the battery module under the balanced target SOC of the candidate module. The total module balancing time includes the passive balancing time T passive And the active equalization time T in the module active For each SOC Ei , the single battery in the battery module is divided into two groups according to its single SOC and SOC Ei The comparison results are divided into two parts, in which the monomer SOC is less than SOC Ei The number of cells in the module is denoted as m. Cells with a cell SOC lower than the target SOC for balancing in the selected candidate module have not yet reached the target SOC and require active balancing charging. Other cells with a cell SOC no lower than the target SOC for balancing in the selected candidate module have exceeded the target SOC and require passive balancing discharge.

[0051] Passive balancing time T within the module passive Indicates that the SOC of the single cell in the battery module is not less than SOCEi The time for passive equalization discharge of single cells can be implemented at the same time. Ei Since each balanced discharge circuit of the single cell passive balancing module 130 uses the same single cell passive balancing resistor, the passive balanced discharge rate of the single cells is the same, and the passive balancing time T in the module is passive Only with the largest single SOC, SOC max The passive equalization discharge time of the single battery is related to the SOC Ei Generally less than SOC max ). Therefore, T passive Calculated by formula (2):

[0052]

[0053] Where C is the rated capacity of the single battery, in Ah; I passive Is the passive balancing current of the single cell, in A. I passive For example, the voltage of a single cell can be divided by the sum of the passive equalization resistance of the single cell corresponding to the single cell and the internal resistance of the single cell. According to the embodiment of the present application, without considering the internal resistance of the single cell, I passive The calculation of can be simplified as the voltage of the single cell divided by the single cell passive balancing resistance corresponding to the single cell.

[0054] Active equalization time T within the module active Indicates that the SOC of all m cells in the battery module is less than SOC Ei The time required for active equalization charging of the single cells. Unlike passive equalization discharge, active equalization charging generally requires charging each single cell separately due to the use of a single external charger, that is, only one single cell in the battery system is charged at the same time. Therefore, T active It should be that for all m monomers whose SOC is less than SOC Ei The total time required for active equalization charging of the single battery cells is calculated by formula (3):

[0055]

[0056] Among them, I active The active balancing current of the single cell is in A, which is related to the charging current provided by the external charger. During the battery charging process, constant current charging is generally adopted, so I active Constant.

[0057] Since each single cell in the battery module is only in one of the active balanced charging state and the passive balanced discharge state, the active balanced charging and passive balanced discharge processes of the single cells of the battery module can be carried out at the same time. Ei The corresponding total balancing time T within the module balance T is the passive balancing time within the module passive And the active equalization time T in the module active The maximum value in , that is, formula (4):

[0058] T balance =max{T passive ,T active} (4)

[0059] For all selected SOC Ei Calculated with the SOC Ei The corresponding total balancing time T within the module balance In the example, select the minimum total equalization time T within the module that takes the least time min The corresponding candidate module internal balance target SOC, SOC Ei As the optimal intra-module balancing target SOC for the battery module E Refer to formula (5) and select the SOC with the shortest time Ei It can ensure the fastest SOC balancing speed within the module, improve SOC balancing efficiency, and save time and cost.

[0060] T min =min{T balance} (5)

[0061] Next, the inter-module balanced target SOC is calculated.

[0062] For multiple battery modules in the battery system, the optimal intra-module balancing target SOC of each battery module is calculated and determined. E Then, the largest optimal intra-module balancing target SOC is selected from all the optimal intra-module balancing targets in these battery modules. E , SOC Emax , and the minimum optimal intra-module balanced target SOC E , SOC Emin The optimal module internal balance target SOC interval [SOC max , SOC min ] arbitrarily select k different SOC values as the target SOC for balancing between candidate modules, SOC Emodulei , where i = 1, 2, 3, ..., k; SOC Emax , SOC Emin and SOC EmoduleiThe unit is %.

[0063] Next, we need to balance the target SOC among these candidate modules. Emodulei The candidate inter-module balancing target SOC that minimizes the SOC balancing time of the battery system is selected as the optimal inter-module balancing target SOC of the battery system. Emodule ) is set as the final balanced target SOC of each single cell in the battery system. Similar to the SOC balancing process of the battery module, the number of enumerations k can be independent of the number of battery modules in the battery system. The larger its value (the denser the selection in the optimal intra-module balanced target SOC range), the more accurate the calculated optimal inter-module balanced target SOC. For example, SOC Emodulei It can be calculated by formula (6), where k SOCs are uniformly selected at the same interval in the optimal module within the target SOC interval. Emodulei .

[0064]

[0065] For each selected SOC Emodulei , respectively calculate the total system balancing time used to balance the battery system SOC under the target SOC between the candidate modules. The total inter-module balancing time includes the system passive balancing time T syspassive and system active balancing time T sysactive For each selected SOC Emodulei The battery module is balanced according to its optimal SOC target within the module E With SOC Emodulei The comparison results are divided into two parts, one of which is the optimal module intra-balanced target SOC E Less than SOC Emodulei The other part is the optimal module internal balance target SOC E Not less than SOC Emodulei battery module.

[0066] For SOC E Not less than SOC Emodulei For the battery module, the current capacity of the battery module has exceeded the selected SOC Emodulei , it needs to be passively balanced and discharged. Passive balancing time between modules T modulepassive Indicates the SOC of the battery system E Not less than SOC Emodulei The time for passive equalization discharge of the battery module. Similar to the passive equalization discharge within the module, these SOC E Not less than SOCEmodulei Since each balanced discharge circuit of the battery module passive balancing module 140 uses the same battery module passive balancing resistor, the passive balanced discharge rate of the battery modules is the same, and the passive balancing time T between modules is the same. modulepassive Only with the maximum SOC E , SOC Emax The passive equalization discharge time of the battery module is related to the Emodulei Less than SOC Emax ). Therefore, T modulepassive Calculated by formula (7):

[0067]

[0068] Among them, C pack is the rated capacity of the battery module, in Ah; I modulepassive I is the passive balancing current of the battery module, in A. modulepassive For example, the voltage of the battery module can be calculated by dividing the voltage of the battery module by the sum of the passive balancing resistance of the battery module corresponding to the battery module and the internal resistance of the single battery of the battery module. According to the embodiment of the present application, without considering the internal resistance of the single battery of the battery module, I modulepassive The calculation can be simplified as the voltage of the battery module divided by the battery module passive balancing resistance corresponding to the battery module.

[0069] In a battery system, the passive equalization discharge of the single cells in a battery module can also be performed simultaneously with the passive equalization discharge between the battery modules. Therefore, the system passive equalization time of the battery system is the same as the passive equalization time of all battery modules and the selected SOC. Emodulei The maximum value of the corresponding passive balancing time between modules is related to the maximum value of the passive balancing time between modules, which is calculated by formula (8):

[0070] T syspassive =max{T passive ,T modulepassive} (8)

[0071] Where T passive It is the intra-module passive balancing time of all battery modules.

[0072] Since active balancing is implemented for single cells in the battery module, the calculation of active balancing time between modules should not only consider the SOC of the battery module, but also the SOC of the battery module. E With SOC Emodulei The comparison results should also consider the single SOC of each single battery in the battery module and the SOC of the battery module. E and SOC EmoduleiFor example, although the SOC of the battery module E Not less than the selected SOC Emodulei However, the SOC of the single battery in the battery module may be lower than the SOC Emodulei In the case of battery module SOC E Less than the selected SOC Emodulei When the SOC of one or some cells in the battery module is greater than the SOC Emodulei .

[0073] There are two cases for calculating the active balancing time between modules.

[0074] When the single cell SOC of the battery module is less than the selected SOC Emodulei And the single cell SOC is greater than the optimal module balancing target SOC of the battery module E When the number of all single cells that meet the condition is recorded as l, it is necessary to actively balance charge all l single cells in each battery module in the battery system to make their single cell SOC reach the selected SOC Emodulei The total time required for active equalization charging of these single cells is taken as the time required for the selected SOC Emodulei Corresponding active balancing time between modules T moduleactive , as shown in formula (9):

[0075]

[0076] Where, j = 1, 2, 3, ..., l; SOC i is the single cell SOC of the single cell that meets the above conditions, in %; C is the rated capacity of the single cell, in Ah; I acive Is the active balancing current of the single cell, in A, which is related to the charging current provided by the external charger. As mentioned above, during the constant current charging process, I active Remain unchanged.

[0077] When the single cell SOC of the battery module is less than the optimal intra-module balancing target SOC of the battery module E When the number of all single cells that meet the condition is recorded as r, it is necessary to actively balance charge all r single cells in each battery module in the battery system so that the optimal module balance target SOC of the battery module where the single cell is located is E Achieve the selected SOC Emodulei The total time required for active equalization charging of these single cells is taken as the time required for the selected SOC Emodulei Corresponding active balancing time between modules T moduleactive, as shown in formula (10):

[0078]

[0079] Where j = 1, 2, 3, ..., r; SOC Ej The SOC of the battery module where the single battery j meets the above conditions is E , unit is %.

[0080] It can be seen that in the above two cases, the optimal intra-module balancing target SOC of the battery module is used. E The maximum value of the single SOC of the single battery in the battery module determines the active equalization charging of the single battery to achieve the selected SOC Emodulei The time required.

[0081] Since the single cells in the battery system need to be actively balanced and charged individually, the active balancing time of the battery system is T sysactive should be consistent with the selected SOC Emodulei Corresponding active balancing time between modules T moduleactive The sum of the active equalization charging time of all battery modules in the battery system is shown in formula (11):

[0082] T sysactive =T moduleactive +T active (11)

[0083] Similar to the active equalization charge in the module, since each single cell is only in one of the active equalization charge state and the passive equalization discharge state, the active equalization charge and passive equalization discharge process of the battery system can be carried out at the same time. Emodulei The corresponding system total equilibrium time T sysbalance is the system passive equilibrium time T syspassive and system active balancing time T sysactive The maximum value in , that is, formula (12):

[0084] T sysbalance =max{T syspassive ,T sysactive} (12)

[0085] For all selected SOC Emodulei Calculated with the SOC Emodulei The corresponding total system equilibrium time T sysbalance In the example, select the minimum total system equilibrium time T that takes the least time sysmin The corresponding candidate module balance target SOC, SOC EmoduleiAs the optimal inter-module balancing target SOC of the battery system Emodule Refer to formula (13) and select the SOC with the shortest time Emodulei It can ensure the fastest system SOC balancing speed, improve the SOC balancing efficiency of the battery system, and save time and cost.

[0086] T sysmin =min{T sysbalance} (13)

[0087] At this point, the controller 170 completes the optimal intra-module balancing target SOC of the battery system. E And the optimal inter-module balanced target SOC Emodule of confirmation.

[0088] Furthermore, the controller 170 can also detect whether the electric vehicle's engine (drive motor) is in an idle state. If the engine is in a non-idle state where it requires power from the battery system, it indicates that the vehicle needs to consume power from the battery system to drive the vehicle, and the SOC of the individual cells will further change. The controller 170 will not perform any further operations. If the engine is in an idle state or a stopped (off) state where it does not consume power from the battery system, it indicates that the vehicle does not urgently need battery power to drive the vehicle, and the battery system's battery SOC balancing can be performed. The controller 170 will then perform any further operations.

[0089] When it is determined that the SOC balancing operation can be further performed, the system 100 determines the optimal intra-module balancing target SOC. E And the optimal inter-module balanced target SOC Emodule , determine the SOC balancing strategy for each battery module in the battery system and the single battery in the battery module.

[0090] Assume that the battery system has p battery modules, and the optimal intra-module balancing target SOC of the i-th battery module is SOC Ei , where i = 1, 2, 3, ..., p. The i-th battery module has q single cells, and the single SOC of the j-th single cell is SOC j , where j = 1, 2, 3, ..., q. As mentioned above, the optimal inter-module balancing target SOC of the battery system is SOC Emodule .

[0091] like Figure 2 As shown, the SOC balancing strategy for the battery system is divided into two independent parts: inter-module SOC balancing control and intra-module SOC balancing control. These two parts can be executed separately or simultaneously.

[0092] exist Figure 2In the inter-module balancing control 200-1 in the upper left part, first, for each battery module, the optimal intra-module balancing target SOC of the battery module i is determined at decision 205. Ei Is it greater than the optimal inter-module balance target? Ei ≤SOC Emodule When the optimal intra-module balancing target SOC of the battery module i is not higher than the optimal inter-module balancing target SOC of the battery system, that is, the balancing target SOC of the battery module i is not greater than the balancing target SOC of the entire battery system, there is no need to perform inter-module passive balancing discharge. At box 208, the system controls the MOS tube 141 in the passive balancing module 140 of the battery module i through the controller 107 to turn off to disable inter-module passive balancing. At this time, it is equivalent to not needing to perform inter-module balancing (passive balancing discharge) control on the battery system.

[0093] When SOC Ei >SOC Emodule When the optimal intra-module balancing target SOC of the battery module i is higher than the optimal inter-module balancing target SOC of the battery system, that is, the balancing target SOC of the battery module i is greater than the balancing target SOC of the entire battery system, it is necessary to control the MOS tube 141 in the passive balancing module 140 of the battery module i to be turned on by the controller 107 at block 206 to connect / start the battery module passive balancing resistor 142, so as to start the inter-module passive balancing for the battery module i to perform passive balancing discharge, so that its SOC reaches the optimal inter-module balancing target SOC of the battery system. Emodule The passive balancing discharge time is calculated by formula (7) as the passive balancing time T between modules. modulepassive Since the passive balanced discharge between multiple battery modules can be performed simultaneously, the optimal intra-module balanced target SOC of all modules can be determined in judgment 205. Ei Higher than the optimal inter-module balancing target SOC of the battery system Emodule The battery modules are used to calculate the passive balancing time T between modules. modulepassive .

[0094] At determination 207 , the controller 107 determines whether the duration T of the passive balancing discharge of the battery module i reaches the inter-module passive balancing time T calculated above. modulepassive If T is not reached modulepassive Then keep the passive balanced discharge state and continue to monitor the duration T. If T is reached modulepassive Then, at block 208, the controller 107 turns off the MOS transistor 141 to disable the passive balancing between modules. Here, the passive balancing time between modules is T modulepassive Determine whether the passive balanced discharge between modules is completed without using the optimal intra-module balanced target SOC EiThe updated value and the optimal inter-module balanced target SOC Emodule The comparison result is that the voltage of the single battery fluctuates, making it impossible to accurately calculate the SOC Ei .

[0095] In the inter-module balancing control 200-1, the passive balancing discharge between modules is mainly completed. According to the embodiment of the present application, for the SOC of battery module i, Ei ≤SOC Emodule Sometimes, active balanced charging control of the single cells in the battery module is required. Figure 2 The module internal balancing control 200 - 2 in the middle and lower half is completed. In fact, the active balancing charging of the battery module is also completed by actively balancing charging each single cell in the battery module that requires active SOC balancing control.

[0096] In the intra-module balancing control 200 - 2 , the system first determines at block 209 whether the optimal intra-module balancing target SOC of the battery module is higher than the optimal inter-module balancing target SOC of the battery system.

[0097] When SOC Ei >SOC Emodule When the optimal intra-module balancing target SOC of the battery module i is higher than the optimal inter-module balancing target SOC of the battery system, that is, the balancing target SOC of the battery module i is greater than the balancing target SOC of the entire battery system, then the battery module i must include at least one single cell j with a single SOC of j Greater than SOC Emodule So that the SOC of battery module i Ei Greater than SOC Emodule .

[0098] Next, in the determination 210 , the SOC of each battery cell j in the battery module i is determined. j Is it less than the optimal intra-module balancing target SOC of battery module i? Ei .

[0099] If the single SOC of single cell j j <SOC Ei, then the SOC of the single cell j is less than the optimal intra-module balancing target SOC, and it needs to be actively balanced and charged. At box 211, the system controls the MOS tube (for example, MOS tube 131a) in the passive balancing circuit corresponding to the single cell j in the single cell passive balancing module 130 through the controller 107 to turn off to turn off the single cell passive balancing resistor (for example, 131b), and controls each of the two MOS tubes in the single cell selection circuit corresponding to the single cell j in the single cell selection module 150 to turn on / off, and controls each of the MOS tubes corresponding to the battery module i and / or the single cell j in the reversing module 150 to turn on / off, so as to start active balancing for the single cell j to perform active balanced charging, so that its SOC reaches the optimal inter-module balancing target SOC of the battery module i. Emodule .

[0100] The active equalization charging time is calculated by formula (3) as the active equalization time T in the module. active At judgment 212, the controller 107 determines whether the duration T of the active equalization charging of the single cell j reaches the active equalization time T calculated above. active If T is not reached active Then maintain active balanced charging state and continue to monitor the duration T. If T is reached active At block 213, the controller 107 controls each of the two MOS transistors in the cell selection circuit corresponding to the cell j to be turned off and controls each of the MOS transistors in the reversing module 150 corresponding to the battery module i and / or the cell j to be turned off, so as to turn off active balancing for the cell j and stop active balancing charging. active The determination of whether active equalization charging is completed lies in the fact that during the active equalization charging process, the voltage of the single cell SOC fluctuates and the SOC of the battery module in which it is located cannot be accurately calculated. Ei .

[0101] If the single SOC of single cell j is j ≥SOC Ei, then the SOC of the single cell j is greater than the intra-module balancing target SOC, and it needs to be passively balanced and discharged. At box 214, the system controls the MOS tube (for example, MOS tube 131a) in the passive balancing circuit corresponding to the single cell j in the single cell passive balancing module 130 through the controller 107 to turn on / connect the single cell passive balancing resistor (for example, 131b), and controls each of the two MOS tubes in the single cell selection circuit corresponding to the single cell j in the single cell selection module 150 to turn off and controls each of the MOS tubes corresponding to the battery module i and / or the single cell j in the reversing module 150 to turn off, so as to turn on passive balancing for the single cell j and turn off active balancing to perform passive balancing discharge, so that its SOC reaches the optimal intra-module balancing target SOC of the battery module i. Emodule .

[0102] At decision 215, the controller 107 determines whether the passive balancing discharge of the cell j reduces the SOC of the cell j. j Achieve the optimal intra-module balancing target SOC of battery module i Ei If SOC is not reached Ei Then maintain the passive balanced discharge state and continue to monitor SOC j If the SOC is reached Ei (i.e. SOC j <SOC Ei ) At block 216, the controller 107 controls the MOS transistor (e.g., MOS transistor 131a) in the passive balancing circuit corresponding to the single cell j in the single cell passive balancing module 130 to turn off, thereby turning off the single cell passive balancing resistor (e.g., 131b), thereby turning off passive balancing for the single cell j and stopping passive balancing discharge.

[0103] For another case in judgment 209, when SOC Ei ≤SOC Emodule When the optimal intra-module balancing target SOC of the battery module i is not higher than the optimal inter-module balancing target SOC of the battery system, that is, the balancing target SOC of the battery module i is not greater than the balancing target SOC of the entire battery system, then the battery module i needs to be actively balanced to make its optimal intra-module balancing target SOC Ei Achieve the optimal inter-module balancing target SOC of the battery system Emodule However, the battery module i may include a single SOC of a single battery j. j Greater than SOC Emodule The situation is such that the single cell j needs passive balanced discharge instead of active balanced charging like other single cells to achieve the SOC of the battery system. Emodule .

[0104] Therefore, next, in the determination 217, the single cell SOC of each single cell j in the battery module i is determined. j Is it less than the optimal inter-module balancing target SOC of the battery system? Emodule .

[0105] If the SOC of the single cell j in the battery module i is j <SOC Emodule , then the SOC of the single cell j is less than the optimal inter-module balancing target SOC, and it needs to be actively balanced and charged. At block 218, the system controls the corresponding parts of the single cell passive balancing module 130, the single cell selection module 150, and the reversing module 150 through the controller 107 to start active balancing for the single cell j to perform active balanced charging, so that its SOC reaches the optimal inter-module balancing target SOC of the battery system. Emodule The operation of the controller 107 starting active balanced charging is similar to that in block 211 .

[0106] At decision 219, the controller 107 determines the SOC of the battery cell j. j Whether the optimal inter-module balancing target SOC of the battery system is achieved Emodule If SOC j Not reaching SOC Emodule Maintain active balanced charging and continue to monitor SOC j If the SOC is reached Emodule (i.e. SOC j <SOC Emodule ) At block 220, the controller 107 controls the corresponding parts of the single cell passive balancing module 130, the single cell selection module 150, and the reversing module 150 to disable active balancing for the single cell j and stop active balancing charging. The active balancing charging time of the single cell j can be determined by the active balancing time T in the module. active The operation of the controller 107 to turn off active equalizing charging is similar to that in block 213 .

[0107] If SOC is determined in decision 217 j ≥SOC Emodule When the battery module i has its single SOC j Greater than the optimal inter-module balancing target SOC of the battery system Emodule If the battery j is in the state of being equalized, the battery j needs to be passively balanced and discharged. At block 221, the system controls the corresponding parts of the battery passive balancing module 130, the battery selection module 150, and the switching module 150 through the controller 107 to start passive balancing for the battery j and perform passive balanced discharge, so that its SOC reaches the optimal inter-module balancing target SOC of the battery system.Emodule The operation of the controller 107 to start the passive balancing discharge is similar to that at block 214 .

[0108] At decision 222, the controller 107 determines the SOC of the battery cell j. j Whether the optimal inter-module balancing target SOC of the battery system is achieved Emodule If SOC j Not reaching SOC Emodule Then maintain the passive balanced discharge state and continue to monitor SOC j If the SOC is reached Emodule (i.e. SOC j <SOC Emodule ) At block 223, the controller 107 controls the corresponding components of the single-cell passive balancing module 130, the single-cell selection module 150, and the reversing module 150 to disable passive balancing for the single cell j, thereby stopping passive balancing discharge. The operation of the controller 107 disabling passive balancing discharge is similar to that at block 216.

[0109] By adopting the above balancing strategy, the system can make the single SOC of each single battery in the battery system and the optimal intra-module balancing target SOC of each battery module reach the target SOC. E Achieve the optimal inter-module balancing target SOC of the battery system Emodule , and ensure that the balancing time of the system SOC balancing process is minimized.

[0110] Figure 3 A schematic flow chart of a method 300 for balancing the SOC of batteries of a battery system according to an embodiment of the present application is shown.

[0111] The method 300 mainly includes steps S310 to S340.

[0112] In step S310, the cell SOC data of the plurality of cells is determined based on the acquired voltages of the plurality of cells, wherein the cell SOC data comprises the cell SOC of each cell. Step S310 is used to monitor the voltages and further the cell SOCs of the cells of the battery system.

[0113] In step S320, the target SOC data for intra-module balancing of each battery module is determined based on the cell SOC data. According to an embodiment, a determination step 301 may be provided between steps S310 and S320 to detect whether a balancing instruction for SOC balancing control of the battery system is enabled. If the balancing instruction is enabled, the method proceeds to step S320; otherwise, the system continuously monitors the cell voltage and cell SOC.

[0114] Step S320 further includes sub-step S321 , wherein for each battery module of the battery system, an optimal intra-module balancing target SOC is selected from candidate intra-module balancing target SOCs to minimize the SOC balancing time of the battery module.

[0115] A candidate intra-module balancing target SOC can be selected from a cell SOC range consisting of the maximum cell SOC and the minimum cell SOC in the cell SOC data of multiple cells in the battery module. In the process of determining the optimal intra-module balancing target SOC, for each candidate intra-module balancing target SOC, the time required for passive balancing discharge of the cell with the maximum cell SOC to bring its cell SOC to the selected candidate intra-module balancing target SOC is calculated as the intra-module passive balancing time of the battery module; the sum of the times required for active balancing charge of all cells whose cell SOC is less than the selected candidate intra-module balancing target SOC to bring their cell SOC to the selected candidate intra-module balancing target SOC is calculated as the intra-module active balancing time of the battery module; the maximum value of the intra-module passive balancing time and the intra-module active balancing time is used as the intra-module total balancing time corresponding to the selected candidate intra-module balancing target SOC; and the candidate intra-module balancing target SOC corresponding to the minimum value of the intra-module total balancing time corresponding to all selected candidate intra-module balancing target SOCs is used as the optimal intra-module balancing target SOC of the battery module.

[0116] After determining parameters such as the optimal intra-module balancing target SOC and the intra-module active balancing time, the method proceeds to step S330, where the inter-module balancing target SOC data for the battery system is determined based on the intra-module balancing target SOC data and the cell SOC data. Step S330 further includes sub-step S331, in which multiple candidate inter-module balancing target SOCs are selected within the optimal intra-module balancing target SOC interval formed by the maximum optimal intra-module balancing target SOC and the minimum optimal intra-module balancing target SOC of the multiple battery modules, and the candidate inter-module balancing target SOC that minimizes the battery system's SOC balancing time is further selected as the optimal inter-module balancing target SOC for the battery system.

[0117] In the process of determining the optimal inter-module balancing target SOC, for each selected candidate inter-module balancing target SOC, the time required for passive balancing discharge of the battery module with the maximum optimal intra-module balancing target SOC so that its optimal intra-module balancing target SOC reaches the selected candidate inter-module balancing target SOC is calculated as the inter-module passive balancing time of the battery system; the inter-module active balancing time of the battery system is calculated; the maximum value of the inter-module passive balancing time corresponding to all selected candidate inter-module balancing target SOCs and the intra-module passive balancing time of all battery modules is used as the system passive balancing time of the battery system; the sum of the inter-module active balancing time corresponding to all selected candidate inter-module balancing target SOCs and the intra-module active balancing time of all battery modules is used as the system active balancing time of the battery system; the maximum value of the system passive balancing time and the system active balancing time is used as the system total balancing time corresponding to the selected candidate inter-module balancing target SOC; and the candidate inter-module balancing target SOC corresponding to the minimum value of the system total balancing time corresponding to all selected candidate inter-module balancing target SOCs is used as the optimal inter-module balancing target SOC of the battery system.

[0118] The active inter-module balancing time of the battery system can be determined in the following two ways: for each battery module, when the single cell SOC of the single cell in the battery module is less than the selected candidate inter-module balancing target SOC and the single cell SOC is greater than the optimal intra-module balancing target SOC of the battery module, the sum of the time required for actively balancing and charging each single cell in the battery module so that its single cell SOC reaches the selected candidate inter-module balancing target SOC is calculated as the active inter-module balancing time; and when the single cell SOC of the single cell in the battery module is less than the optimal intra-module balancing target SOC of the battery module, the sum of the time required for actively balancing and charging each single cell in the battery module so that the optimal intra-module balancing target SOC of the battery module reaches the selected candidate inter-module balancing target SOC is calculated as the active inter-module balancing time.

[0119] After determining the optimal inter-module balancing target SOC and related parameters such as the inter-module passive balancing time, the method determines the SOC balancing strategy for the battery system in step S340 based on the inter-module balancing target SOC data, the intra-module balancing target SOC data, and the cell SOC data. According to one embodiment, a determination step 302 may be provided between steps S330 and S340 to detect whether the electric vehicle requires power from the battery system. If the vehicle does not require power from the battery system, the method proceeds to step S340; otherwise, the system continuously updates information such as the intra-module and inter-module balancing target SOC data.

[0120] In step S340 , an inter-module balancing control strategy is further determined in sub-step S341 and an intra-module balancing control strategy is further determined in step S342 .

[0121] In sub-step S341, for each battery module, when the optimal intra-module balancing target SOC of the battery module is greater than the optimal inter-module balancing target SOC, the battery module is passively balanced and discharged for the inter-module passive balancing time. Furthermore, when the optimal intra-module balancing target SOC of the battery module is not greater than the optimal inter-module balancing target SOC, the battery module is not passively balanced and discharged. Sub-step S341 primarily completes passive balancing discharge control of the battery module.

[0122] In sub-step S342, for each battery module: 1) when the optimal intra-module balancing target SOC of the battery module is greater than the optimal inter-module balancing target SOC, for each single cell in the battery module: when the single cell SOC of the single cell is less than the optimal intra-module balancing target SOC, the single cell is actively balanced and charged for the intra-module active balancing time of the battery module; and when the single cell SOC of the single cell is not less than the optimal intra-module balancing target SOC, the single cell is passively balanced and discharged to make the single cell SOC of the single cell reach the optimal intra-module balancing target SOC. SOC; 2) when the optimal intra-module balancing target SOC of the battery module is not greater than the optimal inter-module balancing target SOC, for each single cell in the battery module: when the single cell SOC of the single cell is less than the optimal inter-module balancing target SOC, the single cell is actively balanced and charged to make the single cell SOC of the single cell reach the optimal inter-module balancing target SOC; and when the single cell SOC of the single cell is not less than the optimal inter-module balancing target SOC, the single cell is passively balanced and discharged to make the single cell SOC of the single cell reach the optimal inter-module balancing target SOC.

[0123] Method 300 is similar to the method described above. Figure 2 Similar parts in the exemplary equalization algorithm are not repeated here.

[0124] By adopting the battery SOC balancing solution proposed in the embodiments of the present application, it is possible to introduce the SOC balancing strategy of the battery module on the basis of the vehicle external charger balancing system without making complex changes to the balancing system components of the battery system, simplifying the battery SOC balancing process for each single cell in the battery system, completing battery characteristic analysis and battery SOC balancing in the shortest possible time, reducing the performance impact of the battery system caused by battery inconsistency, improving the power performance and cruising range of the battery system, and increasing the service life of the battery system, thereby achieving high-speed, efficient and cost-effective battery balancing control.

[0125] It should be noted that although several modules or units of the system for balancing the battery SOC of the battery system are mentioned in the detailed description above, this division is not mandatory. In fact, according to the embodiment of the present application, the features and functions of two or more modules or units described above can be concretized in one module or unit. Conversely, the features and functions of one module or unit described above can be further divided to be concretized by multiple modules or units. The components displayed as modules or units may or may not be physical units, that is, they may be located in one place, or they may be distributed to multiple network units. Some or all of the modules can be selected according to actual needs to achieve the purpose of the solution of the present application. Those of ordinary skill in the art can understand and implement it without paying any creative work.

[0126] In an exemplary embodiment of the present application, a computer-readable storage medium is further provided, on which a computer program is stored. The program includes executable instructions. When the executable instructions are executed by, for example, a processor, the steps of the method for balancing the SOC of batteries in a battery system described in any of the above-described embodiments are implemented. In some possible implementations, various aspects of the present application may also be implemented in the form of a program product, which includes program code. When the program product is executed on a terminal device, the program code is used to cause the terminal device to execute the steps described in the method for balancing the SOC of batteries in a battery system according to various exemplary embodiments of the present application.

[0127] According to an embodiment of the present application, a program product for implementing the above method can be a portable compact disc read-only memory (CD-ROM) and include program code, and can be run on a terminal device, such as a personal computer. However, the program product of the present application is not limited thereto. In this document, a readable storage medium can be any tangible medium containing or storing a program that can be used by or in conjunction with an instruction execution system, apparatus, or device.

[0128] The program product may be implemented in any combination of one or more readable media. The readable medium may be a readable signal medium or a readable storage medium. The readable storage medium may be, for example, but not limited to, an electrical, magnetic, optical, electromagnetic, infrared, or semiconductor system, device, or component, or any combination thereof. More specific examples (a non-exhaustive list) of readable storage media include: an electrical connection with one or more wires, a portable disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber, a portable compact disk read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination thereof.

[0129] The computer-readable storage medium may include a data signal propagated in baseband or as part of a carrier wave, wherein the readable program code is carried. The data signal propagated may take a variety of forms, including but not limited to electromagnetic signals, optical signals, or any suitable combination thereof. The readable storage medium may also be any readable medium other than a readable storage medium, which may send, propagate, or transmit a program for use by or in conjunction with an instruction execution system, device, or component. The program code contained on the readable storage medium may be transmitted using any suitable medium, including but not limited to wireless, wired, optical cable, RF, etc., or any suitable combination thereof.

[0130] The program code for performing the operations of the present application can be written in any combination of one or more programming languages, including object-oriented programming languages such as Java, C++, etc., and conventional procedural programming languages such as "C" or similar programming languages. The program code can be executed entirely on the user computing device, partially on the user device, as a separate software package, partially on the user computing device and partially on a remote computing device, or entirely on a remote computing device or server. In the case of a remote computing device, the remote computing device can be connected to the user computing device through any type of network, including a local area network (LAN) or a wide area network (WAN), or can be connected to an external computing device (e.g., via the Internet using an Internet service provider).

[0131] In an exemplary embodiment of the present application, an electronic device is further provided, which may include a processor and a memory for storing executable instructions of the processor. The processor is configured to execute the executable instructions to perform the steps of the method for balancing the SOC of batteries in a battery system in any of the above embodiments.

[0132] Those skilled in the art will appreciate that various aspects of the present application can be implemented as systems, methods, or program products. Therefore, various aspects of the present application can be specifically implemented in the following forms: a complete hardware implementation, a complete software implementation (including firmware, microcode, etc.), or an implementation that combines hardware and software aspects, which may be collectively referred to herein as a "circuit," "module," or "system."

[0133] Refer to the following Figure 4 4 to describe an electronic device 400 according to this embodiment of the present application. Figure 4 The electronic device 400 shown is merely an example and should not limit the functions and scope of use of the embodiments of the present application.

[0134] like Figure 4 As shown, electronic device 400 is implemented as a general-purpose computing device. Components of electronic device 400 may include, but are not limited to, at least one processing unit 410, at least one storage unit 420, a bus 430 connecting various system components (including storage unit 420 and processing unit 410), a display unit 440, and the like.

[0135] The storage unit stores a program code, which can be executed by the processing unit 410, so that the processing unit 410 performs the steps of various exemplary embodiments of the present application described in the method for balancing the battery SOC of a battery system in this specification. For example, the processing unit 410 can perform the following steps: Figure 3 Follow the steps shown in .

[0136] The storage unit 420 may include a readable medium in the form of a volatile storage unit, such as a random access memory unit (RAM) 4201 and / or a cache memory unit 4202 , and may further include a read-only memory unit (ROM) 4203 .

[0137] The storage unit 420 may also include a program / utility 4204 having a set (at least one) of program modules 4205, such program modules 4205 including but not limited to: an operating system, one or more application programs, other program modules and program data, each of which or some combination may include an implementation of a network environment.

[0138] Bus 430 may represent one or more of several types of bus structures, including a memory bus or memory controller, a peripheral bus, an accelerated graphics port, a processing unit, or a local bus using any of a variety of bus architectures.

[0139] The electronic device 400 can also communicate with one or more external devices 500 (e.g., a keyboard, a pointing device, a Bluetooth device, etc.), one or more devices that enable a user to interact with the electronic device 400, and / or any device that enables the electronic device 400 to communicate with one or more other computing devices (e.g., a router, a modem, etc.). Such communication can occur via an input / output (I / O) interface 450. Furthermore, the electronic device 400 can communicate with one or more networks (e.g., a local area network (LAN), a wide area network (WAN), and / or a public network such as the Internet) via a network adapter 460. The network adapter 460 can communicate with other modules of the electronic device 400 via the bus 430. It should be understood that, although not shown in the figures, other hardware and / or software modules can be used in conjunction with the electronic device 400, including but not limited to microcode, device drivers, redundant processing units, external disk drive arrays, RAID systems, tape drives, and data backup storage systems.

[0140] Through the description of the above embodiments, it is easy for those skilled in the art to understand that the example embodiments described herein can be implemented by software or by combining software with necessary hardware. Therefore, the technical solution according to the embodiments of the present application can be embodied in the form of a software product, which can be stored in a non-volatile storage medium (which can be a CD-ROM, a USB flash drive, a mobile hard disk, etc.) or on a network, and includes several instructions to enable a computing device (which can be a personal computer, a server, or a network device, etc.) to execute the method for balancing the battery SOC of a battery system according to the embodiments of the present application.

[0141] Those skilled in the art will readily appreciate other embodiments of the present application after considering the specification and practicing the contents disclosed herein. This application is intended to cover any variations, uses, or adaptations of the present application that follow the general principles of the present application and include common knowledge or customary techniques in the art not disclosed herein. The description and examples are to be considered merely as exemplary, and the true scope and spirit of the present application are indicated by the appended claims.

Claims

1. A method for balancing the state of charge (SOC) of batteries in a battery system, wherein the battery system includes a plurality of battery modules, each of the battery modules including a plurality of single cells, the method comprising: determining single-cell SOC data of the plurality of single-cell batteries based on the acquired voltages of the plurality of single-cell batteries, the single-cell SOC data including the single-cell SOC of each of the single-cell batteries; Determining the intra-module balancing target SOC data of each battery module based on the single cell SOC data includes, for each battery module, selecting, within a single cell SOC interval consisting of a maximum single cell SOC and a minimum single cell SOC in the single cell SOC data of a plurality of single cells in the battery module, the intra-module balancing target SOC that minimizes the SOC balancing time of the battery module as the optimal intra-module balancing target SOC of the battery module, wherein: Selecting a plurality of intra-module balanced target SOCs from the single-unit SOC range; For each of the selected intra-module balancing target SOCs: Calculating the time required for passively balancing and discharging the single battery cell with the maximum single battery SOC so that its single battery SOC reaches the selected intra-module balancing target SOC as the intra-module passive balancing time of the battery module; Calculating the total time required for active equalization charging of all single cells whose single cell SOC is less than the selected intra-module equalization target SOC so that the single cell SOC reaches the selected intra-module equalization target SOC as the intra-module active equalization time of the battery module; taking the maximum value of the intra-module passive balancing time and the intra-module active balancing time as the intra-module total balancing time corresponding to the selected intra-module balancing target SOC; and The intra-module balancing target SOC corresponding to the minimum value of the total intra-module balancing time corresponding to all selected intra-module balancing target SOCs is used as the optimal intra-module balancing target SOC of the battery module; Determining inter-module balancing target SOC data of the battery system based on the intra-module balancing target SOC data and the cell SOC data includes selecting, within an optimal intra-module balancing target SOC interval consisting of the maximum optimal intra-module balancing target SOC and the minimum optimal intra-module balancing target SOC of the multiple battery modules, an inter-module balancing target SOC that minimizes the SOC balancing time of the battery system as the optimal inter-module balancing target SOC of the battery system, wherein: Selecting a plurality of inter-module balanced target SOCs from the optimal intra-module balanced target SOC interval; For each of the selected inter-module balancing target SOCs: Calculating the time required for passively balancing and discharging the battery module having the maximum optimal intra-module balancing target SOC so that its optimal intra-module balancing target SOC reaches the selected inter-module balancing target SOC as the inter-module passive balancing time of the battery system; and Calculate the active balancing time between modules of the battery system, where For each battery module: When the single cell SOC of a single cell in a battery module is less than the selected inter-module balancing target SOC and the single cell SOC is greater than the optimal intra-module balancing target SOC of the battery module, calculating the sum of the times required to perform active balancing charging on each of the single cells in the battery module so that the single cell SOC reaches the selected inter-module balancing target SOC as the inter-module active balancing time; and When the single cell SOC of a single cell in a battery module is less than the optimal intra-module balancing target SOC of the battery module, the sum of the times required to perform active balancing charging on each of the single cells in the battery module so that the optimal intra-module balancing target SOC of the battery module reaches the selected inter-module balancing target SOC is calculated as the inter-module active balancing time; The maximum value of the inter-module passive balancing time corresponding to all selected inter-module balancing target SOCs and the intra-module passive balancing time of all battery modules is used as the system passive balancing time of the battery system; The sum of the inter-module active balancing time corresponding to all selected inter-module balancing target SOCs and the intra-module active balancing time of all battery modules is used as the system active balancing time of the battery system; Taking the maximum value of the system passive balancing time and the system active balancing time as the system total balancing time corresponding to the selected inter-module balancing target SOC; and Using the inter-module balancing target SOC corresponding to the minimum value of the system total balancing time corresponding to all selected inter-module balancing target SOCs as the optimal inter-module balancing target SOC of the battery system; and An SOC balancing strategy for the battery system is determined based on the inter-module balancing target SOC data, the intra-module balancing target SOC data, and the cell SOC data.

2. The method according to claim 1, characterized in that The SOC balancing strategy includes: For each battery module: When the optimal intra-module balancing target SOC of the battery module is greater than the optimal inter-module balancing target SOC, performing passive balancing discharge on the battery module for the inter-module passive balancing time; and When the optimal intra-module balancing target SOC of the battery module is not greater than the optimal inter-module balancing target SOC, the battery module is not subjected to passive balancing discharge.

3. The method according to claim 1, characterized in that The balancing strategy further includes: For each battery module: When the optimal intra-module balancing target SOC of the battery module is greater than the optimal inter-module balancing target SOC, for each single battery in the battery module: When the single cell SOC of the single cell is less than the optimal intra-module balancing target SOC, actively balancing charging the single cell is continued for the intra-module active balancing time of the battery module; and When the single cell SOC of the single cell is not less than the optimal intra-module balancing target SOC, performing passive balancing discharge on the single cell to make the single cell SOC of the single cell reach the optimal intra-module balancing target SOC; When the optimal intra-module balancing target SOC of the battery module is not greater than the optimal inter-module balancing target SOC, for each single battery in the battery module: When the single cell SOC of the single cell is less than the optimal inter-module balancing target SOC, actively balancing charging the single cell to make the single cell SOC of the single cell reach the optimal inter-module balancing target SOC; and When the single cell SOC of the single cell is not less than the optimal inter-module balancing target SOC, the single cell is subjected to passive balancing discharge to make the single cell SOC of the single cell reach the optimal inter-module balancing target SOC.

4. The method according to any one of claims 1 to 3, characterized in that The method is applied to a power battery system of an electric vehicle.

5. The method according to claim 4, characterized in that Further included equalizing the SOC when the electric vehicle is not using power from the battery system.

6. A balancing system for balancing the state of charge (SOC) of batteries in a battery system, wherein the battery system includes a plurality of battery modules, each of the battery modules includes a plurality of single cells, and the balancing system comprises: A voltage acquisition module, configured to acquire the voltage of the single battery; A single cell passive balancing module, corresponding to each of the single cells and configured to perform passive balancing discharge on the single cells; a battery module passive balancing module corresponding to each of the battery modules and configured to perform passive balancing discharge on the battery modules; a single cell selection module configured to select a single cell to be charged or discharged; a reversing module connected to the battery system and configured to charge or discharge the single battery and / or the battery module; as well as A controller configured to control the voltage acquisition module, the single cell passive balancing module, the battery module passive balancing module, the single cell selection module, and the reversing module connected thereto to balance the state of charge (SOC). The controller is further configured to: determining single-cell SOC data of the plurality of single-cell batteries based on the acquired voltages of the plurality of single-cell batteries, the single-cell SOC data including the single-cell SOC of each of the single-cell batteries; Determining the intra-module balancing target SOC data of each battery module based on the single cell SOC data includes, for each battery module, selecting, within a single cell SOC interval consisting of a maximum single cell SOC and a minimum single cell SOC in the single cell SOC data of a plurality of single cells in the battery module, the intra-module balancing target SOC that minimizes the SOC balancing time of the battery module as the optimal intra-module balancing target SOC of the battery module, wherein: Selecting a plurality of intra-module balanced target SOCs from the single-unit SOC range; For each of the selected intra-module balancing target SOCs: Calculating the time required for passively balancing and discharging the single battery cell with the maximum single battery SOC so that its single battery SOC reaches the selected intra-module balancing target SOC as the intra-module passive balancing time of the battery module; Calculating the total time required for active equalization charging of all single cells whose single cell SOC is less than the selected intra-module equalization target SOC so that the single cell SOC reaches the selected intra-module equalization target SOC as the intra-module active equalization time of the battery module; taking the maximum value of the intra-module passive balancing time and the intra-module active balancing time as the intra-module total balancing time corresponding to the selected intra-module balancing target SOC; and The intra-module balancing target SOC corresponding to the minimum value of the total intra-module balancing time corresponding to all selected intra-module balancing target SOCs is used as the optimal intra-module balancing target SOC of the battery module; determining inter-module balancing target SOC data for the battery system based on the intra-module balancing target SOC data and the cell SOC data, including selecting, within an optimal intra-module balancing target SOC interval consisting of a maximum optimal intra-module balancing target SOC and a minimum optimal intra-module balancing target SOC of the plurality of battery modules, an inter-module balancing target SOC that minimizes the SOC balancing time of the battery system as the optimal inter-module balancing target SOC for the battery system, wherein a plurality of inter-module balancing target SOCs are selected from within the optimal intra-module balancing target SOC interval; For each of the selected inter-module balancing target SOCs: Calculate the time required for passively balancing and discharging the battery module with the maximum optimal intra-module balancing target SOC so that its optimal intra-module balancing target SOC reaches the selected inter-module balancing target SOC as the inter-module passive balancing time of the battery system; and calculate the inter-module active balancing time of the battery system, where For each battery module: When the single cell SOC of a single cell in a battery module is less than the selected inter-module balancing target SOC and the single cell SOC is greater than the optimal intra-module balancing target SOC of the battery module, calculating the sum of the times required to perform active balancing charging on each of the single cells in the battery module so that the single cell SOC reaches the selected inter-module balancing target SOC as the inter-module active balancing time; and When the single cell SOC of a single cell in a battery module is less than the optimal intra-module balancing target SOC of the battery module, the sum of the times required to perform active balancing charging on each of the single cells in the battery module so that the optimal intra-module balancing target SOC of the battery module reaches the selected inter-module balancing target SOC is calculated as the inter-module active balancing time; The maximum value of the inter-module passive balancing time corresponding to all selected inter-module balancing target SOCs and the intra-module passive balancing time of all battery modules is used as the system passive balancing time of the battery system; The sum of the inter-module active balancing time corresponding to all selected inter-module balancing target SOCs and the intra-module active balancing time of all battery modules is used as the system active balancing time of the battery system; Taking the maximum value of the system passive balancing time and the system active balancing time as the system total balancing time corresponding to the selected inter-module balancing target SOC; and Using the inter-module balancing target SOC corresponding to the minimum value of the system total balancing time corresponding to all selected inter-module balancing target SOCs as the optimal inter-module balancing target SOC of the battery system; and An SOC balancing strategy for the battery system is determined based on the inter-module balancing target SOC data, the intra-module balancing target SOC data, and the cell SOC data.

7. The balancing system according to claim 6, characterized in that: The SOC balancing strategy includes: For each battery module: When the optimal intra-module balancing target SOC of the battery module is greater than the optimal inter-module balancing target SOC, performing passive balancing discharge on the battery module for the inter-module passive balancing time; and When the optimal intra-module balancing target SOC of the battery module is not greater than the optimal inter-module balancing target SOC, the battery module is not subjected to passive balancing discharge.

8. The balancing system according to claim 6, characterized in that: The balancing strategy further includes: For each battery module: When the optimal intra-module balancing target SOC of the battery module is greater than the optimal inter-module balancing target SOC, for each single battery in the battery module: When the single cell SOC of the single cell is less than the optimal intra-module balancing target SOC, actively balancing charging the single cell is continued for the intra-module active balancing time of the battery module; and When the single cell SOC of the single cell is not less than the optimal intra-module balancing target SOC, performing passive balancing discharge on the single cell to make the single cell SOC of the single cell reach the optimal intra-module balancing target SOC; When the optimal intra-module balancing target SOC of the battery module is not greater than the optimal inter-module balancing target SOC, for each single battery in the battery module: When the single cell SOC of the single cell is less than the optimal inter-module balancing target SOC, actively balancing charging the single cell to make the single cell SOC of the single cell reach the optimal inter-module balancing target SOC; and When the single cell SOC of the single cell is not less than the optimal inter-module balancing target SOC, the single cell is subjected to passive balancing discharge to make the single cell SOC of the single cell reach the optimal inter-module balancing target SOC.

9. The balancing system according to any one of claims 6 to 8, characterized in that: The balancing system is applied to a power battery system of an electric vehicle.

10. The balancing system according to claim 9, characterized in that: The controller is further configured to equalize the SOC when the electric vehicle is not using power from the battery system.

11. An electric vehicle comprising: A battery system comprising a plurality of battery modules, each of which comprises a plurality of single cells; as well as An equalizing system according to any one of claims 6 to 10. 12 . A computer-readable storage medium having stored thereon a computer program comprising executable instructions, which, when executed by a processor, cause the processor to implement the method according to claim 1 .

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