Battery pack balancing method, device, vehicle and storage medium

Abstract

The present application relates to the field of battery technology, and in particular to a battery pack balancing method, device, vehicle and storage medium, wherein the method includes: judging whether the current battery pack meets the preset offline balancing conditions; if the current battery pack meets the preset offline balancing conditions, then determining the target battery cell to be balanced in the current battery pack, the balancing time of the target battery cell and the periodic wake-up duration; balancing the target battery cell according to the balancing time of the target battery cell, and controlling the battery management system to enter the sleep mode, and obtaining the duration of the battery management system entering the sleep mode, and waking up the battery management system when the duration reaches the periodic wake-up duration, and re-judging whether the current battery pack meets the preset offline balancing conditions. Thus, the problem that the related technology cannot accurately judge the target battery cell that needs to be balanced, and cannot maintain the balance between the consistency of the battery cells and the higher energy of the vehicle is solved, and the balancing target is more accurate.

Description

Technical Field

[0001] The present application relates to the field of battery technology, and in particular to a battery pack balancing method, device, vehicle and storage medium. Background Art

[0002] The battery capacity used in current electric vehicles is getting larger and larger. As the vehicle is used and the battery itself ages, the inconsistency between battery cells will become worse and worse.

[0003] For the purpose of ensuring the consistency between battery cells, the general balancing function developed, either active balancing or passive balancing, is to perform passive discharge or energy transfer between cells based on the pressure difference or the SOC (State of Charge) difference between cells when the vehicle battery management system is awakened. This method is mainly performed when the vehicle is awakened, and due to the limitation of the balancing circuit itself, it works well for batteries with smaller ampere-hours. For batteries with very large capacity, due to the limited operating time, the overall operating time for passenger cars is about 2 hours to 4 hours per day, and it cannot achieve the purpose well and cannot ensure the consistency between cells.

[0004] The general offline balancing developed on this basis focuses on extending the balancing time. Before the main controller of the battery management system enters sleep mode, the battery monitoring unit acquisition chip is activated to enter the offline balancing mode, and the balancing cells, balancing time, and duty cycle are set. After that, the main controller enters sleep mode, and the acquisition chip performs balancing on the balancing cells according to the expected duty cycle based on preset parameters until the set balancing time is reached. In this way, the balancing operation time is no longer constrained by the vehicle system operation time.

[0005] However, due to problems such as single cell voltage polarization and SOC error during operation, the balancing time calculation is inaccurate. If a serious fault occurs in the balancing circuit or the acquisition circuit, the system will be unable to balance the corresponding battery cells or will incorrectly balance the target battery cells, affecting the balancing effect. At the same time, since offline balancing is performed in the sleep mode of the main control unit, the battery cell acquisition unit does not have the ability to calculate and judge the system status. If an abnormal fault occurs, it cannot respond in time, and ultimately cannot maintain a high level of single cell consistency. Summary of the invention

[0006] The present application provides a battery pack balancing method, device, vehicle and storage medium to solve the problems that the related technology cannot accurately determine the target battery cell that needs to be balanced, cannot maintain the balance between the consistency of battery cells and the higher energy of the vehicle, and abnormal conditions lead to misjudgment or balancing failure. The balancing target is more accurate, the reliability and availability of software functions are improved, and a higher vehicle available charging and discharging energy is maintained on the basis of maintaining the consistency of battery cells.

[0007] A first aspect of the present application provides a battery pack balancing method, comprising the following steps: determining whether a current battery pack meets a preset offline balancing condition; if the current battery pack meets the preset offline balancing condition, determining a target battery cell to be balanced in the current battery pack, a balancing time of the target battery cell, and a periodic wake-up duration; and balancing the target battery cell according to the balancing time of the target battery cell, and controlling a battery management system to enter a sleep mode, and obtaining a duration for the battery management system to enter the sleep mode, and when the duration reaches the periodic wake-up duration, waking up the battery management system, and re-determining whether the current battery pack meets the preset offline balancing condition, until the current battery pack does not meet the preset offline balancing condition.

[0008] Optionally, in some embodiments, determining whether the current battery pack meets the preset offline balancing conditions includes: obtaining the current operating condition of the vehicle, the status information of the battery pack, and the status information of the battery management system; if the current operating condition of the vehicle, the status information of the battery pack, and the status information of the battery management system all meet their respective corresponding preset balancing conditions, then determining that the current battery pack meets the preset offline balancing conditions.

[0009] Optionally, in some embodiments, determining the target battery cell to be balanced in the current battery pack, the balancing time and the periodic wake-up duration of the target battery cell includes: collecting current battery information and unit circuit information of the current battery pack; calculating the voltage difference between each single cell and the minimum single cell based on the current battery information and the unit circuit information, and determining the target battery cell according to the voltage difference and an offline balancing voltage difference threshold, wherein the offline balancing voltage difference threshold is determined by the balancing capability of the battery management system and the consistency of the vehicle cells.

[0010] Optionally, in some embodiments, before determining whether the current battery pack meets the preset offline balancing condition, it also includes: initializing the battery management system based on a preset initialization strategy; after the initialization is completed, self-checking the battery management system based on a preset self-check strategy, and after the self-check is completed, periodically checking the voltage and temperature of each single cell.

[0011] Optionally, in some embodiments, after obtaining the duration of the battery management system entering the sleep mode, it also includes: before the duration reaches the periodic wake-up duration, determining whether a wake-up instruction is received; if the wake-up instruction is received, initializing the battery management system based on the preset initialization strategy.

[0012] A second aspect of the present application provides a battery pack balancing device, comprising: a judgment module, used to judge whether a current battery pack meets a preset offline balancing condition; a determination module, used to determine a target battery cell to be balanced in the current battery pack, a balancing time of the target battery cell and a periodic wake-up duration when the current battery pack meets the preset offline balancing condition; and a balancing module, used to balance the target battery cell according to the balancing time of the target battery cell, and control a battery management system to enter a sleep mode, and obtain the duration of the battery management system entering the sleep mode, and wake up the battery management system when the duration reaches the periodic wake-up duration, and re-judge whether the current battery pack meets the preset offline balancing condition, until the current battery pack does not meet the preset offline balancing condition.

[0013] Optionally, in some embodiments, the judgment module is also used to: obtain the current operating condition of the vehicle, the status information of the battery pack and the status information of the battery management system; if the current operating condition of the vehicle, the status information of the battery pack and the status information of the battery management system all meet their respective corresponding preset balancing conditions, then determine that the current battery pack meets the preset offline balancing condition.

[0014] Optionally, in some embodiments, the determination module is also used to: collect current battery information and unit circuit information of the current battery pack; calculate the voltage difference between each single cell and the minimum single cell based on the current battery information and the unit circuit information, and determine the target battery cell according to the voltage difference and the offline equalization pressure difference threshold, wherein the offline equalization pressure difference threshold is determined by the equalization capability of the battery management system and the consistency of the vehicle cells.

[0015] Optionally, in some embodiments, before determining whether the current battery pack meets the preset offline balancing condition, the judgment module is further used to: initialize the battery management system based on a preset initialization strategy; after the initialization is completed, self-check the battery management system based on a preset self-check strategy, and after the self-check is completed, periodically check the voltage and temperature of each single cell.

[0016] Optionally, in some embodiments, after obtaining the duration of the battery management system entering the sleep mode, the balancing module is also used to: determine whether a wake-up instruction is received before the duration reaches the periodic wake-up duration; if the wake-up instruction is received, initialize the battery management system based on the preset initialization strategy.

[0017] A third aspect of the present application provides a vehicle, comprising: a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the program to implement the battery pack balancing method as described in the above embodiment.

[0018] A fourth aspect of the present application provides a computer-readable storage medium having a computer program stored thereon, the program being executed by a processor to implement the battery pack balancing method as described in the above embodiment.

[0019] Therefore, when the current battery pack meets the offline balancing conditions, the target battery cell that needs to be balanced, the balancing time of the target battery cell and the periodic wake-up time can be determined, and the target battery cell can be balanced according to the balancing time of the target battery cell, and the battery management system can be controlled to enter the sleep mode, and the battery management system can be periodically woken up to re-judge whether the current battery pack meets the offline balancing conditions until the current battery pack does not meet the offline balancing conditions. In this way, the problems that the related technology cannot accurately judge the target battery cell that needs to be balanced, cannot maintain the balance between the consistency of battery cells and the higher energy of the vehicle, and abnormal conditions lead to misjudgment or balancing failure are solved. The balancing target is more accurate, the reliability and availability of the software function are improved, and the higher available charging and discharging energy of the vehicle is maintained on the basis of maintaining the consistency of battery cells.

[0020] Additional aspects and advantages of the present application will be given in part in the description below, and in part will become apparent from the description below, or will be learned through the practice of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The above and / or additional aspects and advantages of the present application will become apparent and easily understood from the following description of the embodiments in conjunction with the accompanying drawings, in which:

[0022] Figure 1 A flowchart of a battery pack balancing method provided according to an embodiment of the present application;

[0023] Figure 2 A flowchart of determining a target balanced cell according to a specific embodiment of the present application;

[0024] Figure 3 A flowchart of a battery pack calibration test provided according to a specific embodiment of the present application;

[0025] Figure 4 A schematic diagram of a battery pack calibration test MAP provided according to a specific embodiment of the present application;

[0026] Figure 5 A flowchart of calculating the sleep time according to a specific embodiment of the present application;

[0027] Figure 6 A flowchart of a battery pack balancing method provided according to a specific embodiment of the present application;

[0028] Figure 7 A block diagram of a battery pack balancing device provided according to an embodiment of the present application;

[0029] Figure 8 It is a schematic diagram of the structure of a vehicle provided according to an embodiment of the present application. DETAILED DESCRIPTION

[0030] Embodiments of the present application are described in detail below, and examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present application, and should not be construed as limiting the present application.

[0031] The following describes the battery pack balancing method, device, vehicle and storage medium of the embodiment of the present application with reference to the accompanying drawings. In view of the problem that the technology mentioned in the above background technology cannot accurately determine the target battery cell that needs to be balanced, cannot maintain the balance between the consistency of the battery cell and the higher energy of the vehicle, and the abnormal state causes misjudgment or equalization failure, the present application provides a battery pack balancing method, in which the target battery cell that needs to be balanced, the balancing time of the target battery cell and the periodic wake-up time are determined under the offline balancing condition, and the target battery cell is balanced according to the balancing time of the target battery cell, and the battery management system is controlled to enter the sleep mode, and the battery management system is periodically awakened to further determine whether the offline balancing condition is met. Thus, the problem that the related technology cannot accurately determine the target battery cell that needs to be balanced, cannot maintain the balance between the consistency of the battery cell and the higher energy of the vehicle, and the abnormal state causes misjudgment or equalization failure is solved, the balancing target is more accurate, the reliability and availability of the software function are improved, and the higher vehicle available charging and discharging energy is maintained on the basis of maintaining the consistency of the battery cell.

[0032] Specifically, Figure 1 A schematic flow chart of a battery pack balancing method provided in an embodiment of the present application.

[0033] like Figure 1 As shown, the battery pack balancing method includes the following steps:

[0034] In step S101 , it is determined whether the current battery pack meets a preset offline balancing condition.

[0035] Optionally, in some embodiments, determining whether the current battery pack meets the preset offline balancing conditions includes: obtaining the current operating condition of the vehicle, the status information of the battery pack, and the status information of the battery management system; if the current operating condition of the vehicle, the status information of the battery pack, and the status information of the battery management system all meet their respective corresponding preset balancing conditions, then determining that the current battery pack meets the preset offline balancing conditions.

[0036] Among them, the preset offline balancing condition may be that the current operating conditions allow offline balancing, and there are no abnormalities in the battery pack status information and the battery management system status information. Among them, the battery pack status information being normal may include that the polarization phenomenon has been eliminated when the battery cell OCV (Open circuit voltage) is awakened.

[0037] It is understandable that the current level of electrification of vehicles is very high, and they will experience various working conditions throughout their life cycle, which greatly tests the reliability and availability of software functions. If there are problems such as loose connectors, poor contact of the collection harness, short circuit or open circuit, and aging of the line during the operation of the vehicle, the functions of the main control and collection units will be affected. At this time, the collection unit will occasionally have inaccurate data collection, drifting up and down, and the main control unit will perform logical judgment or fault warning. On the one hand, it takes a certain amount of time, and on the other hand, it needs to consider different working conditions for different treatments. These will affect the activation and operation of the system balancing function. Therefore, when the vehicle disconnects the relay and is in a relatively stable state, the embodiment of the present application performs a basic status check to determine whether the offline balancing activation conditions are met.

[0038] Specifically, the battery cell acquisition unit periodically acquires the cell voltage and temperature and sends them to the main control unit. The main control unit executes functional logic and state calculation based on the current system state and cell state information. The main control unit is ready to power off and sleep. At this time, after logical judgment, the main control unit determines whether offline balancing is supported based on the cell voltage, cell temperature, and acquisition board information input by the battery cell acquisition unit, combined with the current working condition of the vehicle, whether the battery pack status information and the battery management system status information are suitable for offline balancing, and comprehensively determines whether the preset offline balancing conditions are met. Among them, the main control unit can be the main logic control board of the battery management system, and the acquisition unit can be the acquisition board of the cell voltage and temperature of the battery management system, and perform the balancing function at the same time. Specifically, if the current working condition of the vehicle does not allow offline balancing, it will not enter; if the system does not eliminate the polarization phenomenon when waking up the battery cell OCV, it can not enter; based on multi-point physical failure considerations, if the battery system has various abnormal faults, such as acquisition circuit line faults, cell undervoltage faults, overtemperature faults, etc., it can not enter.

[0039] In step S102 , if the current battery pack meets the preset offline balancing condition, the target battery cell to be balanced in the current battery pack, the balancing time of the target battery cell and the periodic wake-up duration are determined.

[0040] Optionally, in some embodiments, the target battery cell to be balanced in the current battery pack, the balancing time of the target battery cell and the periodic wake-up duration are determined, including: collecting the current battery information and unit circuit information of the current battery pack; calculating the voltage difference between each single cell and the minimum single cell based on the current battery information and unit circuit information, and determining the target battery cell according to the voltage difference and the offline balancing voltage difference threshold, wherein the offline balancing voltage difference threshold is determined by the balancing capability of the battery management system and the consistency of the vehicle cells.

[0041] It should be noted that during the operation of the vehicle, the accurate OCV voltage and SOC cannot be obtained due to the continuous charging and discharging of the cells, and the balanced target cell cannot be accurately determined at this time. The implementation of this application can obtain the maximum time parameter TOCV after the current cell stops charging and discharging under extreme working conditions and the cell voltage eliminates the polarization phenomenon. The main control unit starts timing after disconnecting the relay. After the TOCV time, the OCV voltage is collected based on the current state information, the SOC value is corrected, and the balanced target cell is determined.

[0042] Specifically, the main control unit is ready to power off and sleep. After logical judgment, it is determined that the offline balancing function can be activated. Then, the target battery cell to be balanced and the corresponding balancing time are determined, and the time the system needs to sleep is calculated. Specifically, Figure 2 As shown, the main control unit periodically calls the acquisition unit AFE (Active Front End) to collect current battery information and acquisition unit circuit information; the main control unit determines the voltage difference between each cell and the minimum cell voltage; the main control unit compares the voltage difference of each cell with the preset voltage difference threshold to determine the balanced target cell.

[0043] The setting of the preset pressure difference threshold of equalization needs to consider the requirements of system equalization capability and vehicle single-cell consistency, among which: the system equalization capability needs to consider the effective equalization current and equalization time of the equalization circuit (the offline equalization time is controllable, but less than the vehicle sleep time);

[0044] Effective balancing current x daily offline balancing time = maximum balancing capacity value / day, recorded as C offBalance

[0045] The vehicle cell consistency requirement needs to take into account the vehicle's available charging and discharging energy under charging and discharging conditions after the vehicle is balanced.

[0046] It should be noted that the offline equalization pressure difference threshold of the embodiment of the present application can be determined by the equalization capability of the battery management system and the consistency of the vehicle cells.

[0047] Specifically, Figure 3 As shown, the embodiment of the present application can obtain the corresponding MAP relationship through testing, and then determine the offline equalization pressure difference threshold:

[0048] t0: Initial ambient temperature of battery pack test

[0049] Static phase:

[0050] T.1 At the battery pack level, one or a small number of cells are manufactured with a certain voltage difference D1mV compared to the current common cells. The D1 value is set as follows Figure 4 As shown in the MAP table;

[0051] T.2 After being stationary for T0 hours, the battery pack temperature and ambient temperature are consistent, the main control unit calculates the accurate SOC and collects stable OCV.

[0052] Charging stage:

[0053] T.3 Perform full charge and record the charged energy value, recorded as Q1, and the final single cell voltage difference is D2mV

[0054] Discharge phase:

[0055] T.4 Execute full discharge and record the released energy value, recorded as Q2, and the final single cell voltage difference is D3mV

[0056] The specific methods of full charge and full discharge tests can refer to the national standard GB / T31467.1 / .2, or be defined by yourself. The operations between charging and discharging, such as current control, static operation, etc., will not be repeated here.

[0057] The final formation is similar to Figure 4 The MAP table shown is based on the above data and ultimately on the impact of the single cell pressure difference on the vehicle's charging and discharging energy. Within the vehicle's cumulative full charging and discharging cycle time, a relatively small offline balancing threshold is selected:

[0058] Calculate C total =C offBalance xT Sleep xT interval

[0059] Among them, C total is the theoretical value of equilibrium capacity, T interval T is the time interval between the vehicle's cumulative full charge and discharge energy, in days. Sleep is the vehicle sleep time per day, in hours, C offBalance It is the balanced maximum capacity value / day.

[0060] Based on the initial cell voltage difference D1, Q1 and Q2 test data, determine the minimum cell voltage requirement that the vehicle can accept, based on Ctotal Relating to the initial monomer voltage D1, the threshold within the final selected equalization capability is determined. The off-line equalization trigger threshold can be slightly smaller than the vehicle target value to prevent the equalization judgment state from jumping.

[0061] Through certain tests, based on the relationship between the vehicle monomer voltage difference and the charge and discharge energy, the monomer voltage difference threshold D to be maintained under the condition of vehicle parking is determined. refer During the actual project implementation, the entry threshold D1 for off-line equalization can be slightly smaller than D. refer Since the current battery monomer capacity is very large, it takes about 10 hours to equalize about 1 Ah of electricity, which is approximately equal to 1% SOC or an 8 - 10 mV voltage difference. Therefore, the equalization cut-off voltage D2 is set based on the main control unit's self-wake-up cycle and equalization capability, and is set to a smaller value, D2 << D1 (much smaller than), so that the controller cannot reach this target within one self-wake-up cycle.

[0062] During each controller self-wake-up cycle: If the monomer voltage difference D elta OCV > D1 and the entry condition is satisfied, then further perform off-line equalization. If the monomer voltage difference D elta OCV < D1, which is less than the entry condition, no off-line equalization will be performed this time. Thus, on the one hand, the trigger frequency of off-line equalization can be reduced. At the same time, long-term execution can effectively maintain the monomer consistency at a relatively high level. In addition, the vehicle will not waste too much energy.

[0063] The equalization time of the target cell in the embodiment of this application is calculated as follows:

[0064] T offbalance = C(D trigger , D end ) / I

[0065] Among them, T offbalance is the equalization time of the target monomer, C is the capacity that the target monomer needs to equalize, D trigger is the off-line equalization trigger voltage difference threshold, D end is the off-line equalization voltage difference end threshold, and I is the effective equalization current.

[0066] D end The threshold is set based on the requirement of reducing the 12V power consumption of the vehicle and can be set to a target value that cannot be reached during the current subsystem sleep time. On the one hand, it can reduce the vehicle power consumption. At the same time, considering software multiple failures and memory area read and write problems, after waking up again from sleep, all parameters are reset during the system initialization process and used again without setting other thresholds, reducing software complexity and improving software reliability.

[0067] The main logic for calculating the sleep time in the specific setting of the sleep time, setting the target equalization cell, and setting the equalization time is as Figure 5 shown.

[0068] S501: If the vehicle is under intense charging and discharging conditions, set the offline balancing to not be performed and set the next sleep time to T. polarization , T polarization is the duration for the monomer OCV polarization phenomenon to completely disappear.

[0069] S502, determining the wakeup source of the current wakeup, and determining whether it is a vehicle wakeup or a self-wakeup.

[0070] S503, calculate the last sleep time and determine whether the last sleep time exceeds the parameter T polarization , if it exceeds, offline balancing can be performed during this hibernation.

[0071] S504: If offline balancing is not performed this time, set the next sleep time to T polarization If offline balancing is performed this time, the next sleep time is set to the periodic time T regular , where the periodic time T regular It is necessary to confirm with the vehicle and set a time threshold under the premise of reducing the power consumption of the vehicle's 12V power supply.

[0072] In step S103, the target battery cell is balanced according to the balancing time of the target battery cell, and the battery management system is controlled to enter the sleep mode, and the duration of the battery management system entering the sleep mode is obtained, and when the duration reaches the periodic wake-up duration, the battery management system is awakened, and it is re-determined whether the current battery pack meets the preset offline balancing conditions, until the current battery pack does not meet the preset offline balancing conditions.

[0073] It should be understood by those skilled in the art that when the system performs offline balancing, the main control unit is in a dormant state and does not perform any data calculations or logic processing. At this time, if there are line problems, acquisition unit chip problems, balancing circuit problems, internal short circuits in the battery pack, and other faults, more severe faults such as acquisition data drift, balancing circuit short circuits, and battery cell over-discharge will occur during the balancing circuit startup process, and the main control unit cannot handle them. In the embodiment of the present application, after the main control unit triggers the offline balancing function, it can periodically perform self-wake-up, perform initialization to detect the status of the entire system, and determine whether to further perform offline balancing.

[0074] Specifically, the main control unit sets the sleep time and sends it to the RTC (Real_Time Clock) or SBC (System Basis Chip), sets the balancing target cell and the corresponding balancing time and sends them to the battery cell acquisition unit. The battery cell acquisition unit sets the balancing target cell and the corresponding balancing time, as well as the balancing duty cycle based on the signal of the main control unit, and writes them into the AFE register. The main control unit goes into sleep mode, the RTC or SBC enters the low power mode, starts timing, and the battery cell acquisition unit enters the offline balancing mode. According to the information written in the register, the target cell is executed according to the set duty cycle and time, and after the main control unit triggers the offline balancing function, it periodically performs self-wake-up, performs initialization to detect the status of the entire system, and determines whether to further perform offline balancing.

[0075] Optionally, in some embodiments, before determining whether the current battery pack meets the preset offline balancing conditions, it also includes: initializing the battery management system based on a preset initialization strategy; after the initialization is completed, self-testing the battery management system based on a preset self-test strategy, and after the self-test is completed, periodically testing the voltage and temperature of each single cell.

[0076] The preset initialization strategy and the preset self-check strategy may be preset by relevant personnel and are not specifically limited here.

[0077] Specifically, before determining whether the current battery pack meets the preset offline balancing condition, the battery management system is initialized.

[0078] 1. The main control unit wakes up, systematically performs initialization of the entire system, and initializes the battery cell acquisition unit.

[0079] 2. The battery cell collection unit is initialized, the offline balancing function is stopped, the collection unit and the main control unit are started, and the communication between the collection unit and the main control unit is started, and the collection of cell voltage and temperature is started.

[0080] 3. The main control unit starts self-checking the entire system to detect the current system hardware and software status, including hardware chips, circuits, various acquisition lines, and sensor status.

[0081] 4. The battery cell data collection unit completes initialization, starts periodically collecting cell voltage and temperature, and sends them to the main control unit.

[0082] 5. The main control unit starts to operate normally and periodically detects and determines the single cell voltage and temperature.

[0083] Optionally, in some embodiments, after obtaining the duration of the battery management system entering the sleep mode, it also includes: before the duration reaches the periodic wake-up duration, determining whether a wake-up instruction is received; if a wake-up instruction is received, initializing the battery management system based on a preset initialization strategy.

[0084] In the actual implementation process, in addition to periodic self-wake-up, the vehicle will also accept other wake-up methods, such as user wake-up. Before the duration of the periodic wake-up reaches the duration of the periodic wake-up, it will determine whether the wake-up command has been received. If the wake-up execution is received, the battery management system will be initialized based on the preset initialization strategy to further determine whether offline balancing is required.

[0085] In order to enable relevant technical personnel in the art to further understand the battery pack balancing method of the embodiment of the present application, it is described in detail below in conjunction with specific embodiments.

[0086] like Figure 6 As shown, Figure 6 A battery pack balancing method is provided according to an embodiment of the present application.

[0087] The main control unit initializes the system status and the acquisition unit. The acquisition unit stops the offline function and is initialized. The main control unit performs a system self-check. The acquisition unit completes the acquisition of the battery cell voltage and temperature and transmits the collected battery voltage and temperature to the main control unit. The active unit runs the system, periodically detects the cell voltage and temperature, and performs logical and operations based on the current status. It activates offline balancing, calculates offline balancing cells and time, calculates sleep time, and sets the sleep time, sets the balancing target cells, sets the balancing time, and transmits the set balancing cells and time to the acquisition unit. The acquisition unit writes to the AFE register, the active unit goes into sleep, and the acquisition unit enters offline balancing.

[0088] Therefore, the main control unit will time TOCV after disconnecting the relay, and after the polarization voltage is eliminated, the single cell voltage will be collected again for balancing judgment. At this time, there is no single cell charging and discharging polarization phenomenon, the obtained single cell OCV voltage is more accurate, and the balancing target is more accurate; the main control unit will judge whether to perform the offline balancing function after the vehicle disconnects the relay and the battery cell is in a stable state and performs basic system status detection. It will also periodically wake up and detect the system software and hardware status, which can improve the circuit fault detection coverage. The controller can avoid circuit aging or other occasional faults, and avoid balancing failure due to circuit problems. Based on multi-point failure analysis, the software function reliability and availability are higher.

[0089] According to the battery pack balancing method proposed in the embodiment of the present application, by judging whether the vehicle meets the offline balancing conditions, and determining the target battery cell that needs to be balanced, the balancing time of the target battery cell and the periodic wake-up duration when the offline balancing conditions are met, the target battery cell is balanced according to the balancing time of the target battery cell, and the battery management system is controlled to enter the sleep mode, and the battery management system is periodically woken up to further judge whether the offline balancing conditions are met. Thus, the problems that the related technology cannot accurately judge the target battery cell that needs to be balanced, cannot maintain the balance between the consistency of the battery cells and the higher energy of the vehicle, and the abnormal state causes misjudgment or balancing failure are solved. The balancing target is more accurate, the reliability and availability of the software function are improved, and the higher available charging and discharging energy of the vehicle is maintained on the basis of maintaining the consistency of the battery cells.

[0090] Next, a battery pack balancing device according to an embodiment of the present application is described with reference to the accompanying drawings.

[0091] Figure 7 It is a block diagram of a battery pack balancing device according to an embodiment of the present application.

[0092] like Figure 7 As shown, the battery pack balancing device 10 includes: a judgment module 100 , a determination module 200 and a balancing module 300 .

[0093] Among them, the judgment module 100 is used to judge whether the current battery pack meets the preset offline balancing conditions; the determination module 200 is used to determine the target battery cell to be balanced in the current battery pack, the balancing time of the target battery cell and the periodic wake-up time when the current battery pack meets the preset offline balancing conditions; and the balancing module 300 is used to balance the target battery cell according to the balancing time of the target battery cell, and control the battery management system to enter the sleep mode, and obtain the duration of the battery management system entering the sleep mode, and when the duration reaches the periodic wake-up time, wake up the battery management system, and re-judge whether the current battery pack meets the preset offline balancing conditions, until the current battery pack does not meet the preset offline balancing conditions.

[0094] Optionally, in some embodiments, the judgment module 100 is also used to: obtain the current operating condition of the vehicle, the status information of the battery pack and the status information of the battery management system; if the current operating condition of the vehicle, the status information of the battery pack and the status information of the battery management system all meet their respective corresponding preset balancing conditions, then it is determined that the current battery pack meets the preset offline balancing conditions.

[0095] Optionally, in some embodiments, the determination module 200 is also used to: collect current battery information and unit circuit information of the current battery pack; calculate the voltage difference between each single cell and the minimum single cell based on the current battery information and unit circuit information, and determine the target battery cell according to the voltage difference and the offline equalization voltage difference threshold, wherein the offline equalization voltage difference threshold is determined by the equalization capability of the battery management system and the consistency of the vehicle cells.

[0096] Optionally, in some embodiments, before determining whether the current battery pack meets the preset offline balancing conditions, the judgment module 200 is also used to: initialize the battery management system based on a preset initialization strategy; after the initialization is completed, self-check the battery management system based on a preset self-check strategy, and after the self-check is completed, periodically check the voltage and temperature of each single cell.

[0097] Optionally, in some embodiments, after obtaining the duration of the battery management system entering the sleep mode, the balancing module 300 is also used to: determine whether a wake-up instruction is received before the duration reaches the periodic wake-up duration; if a wake-up instruction is received, initialize the battery management system based on a preset initialization strategy.

[0098] It should be noted that the above explanations of the embodiment of the battery pack balancing method are also applicable to the battery pack balancing device of this embodiment, which will not be described in detail here.

[0099] According to the battery pack balancing device proposed in the embodiment of the present application, by judging whether the vehicle meets the offline balancing conditions, and determining the target battery cell that needs to be balanced, the balancing time of the target battery cell and the periodic wake-up duration when the offline balancing conditions are met, the target battery cell is balanced according to the balancing time of the target battery cell, and the battery management system is controlled to enter the sleep mode, and the battery management system is periodically woken up to further judge whether the offline balancing conditions are met. Thus, the problems that the related technology cannot accurately judge the target battery cell that needs to be balanced, cannot maintain the balance between the consistency of the battery cells and the higher energy of the vehicle, and the abnormal state causes misjudgment or balancing failure are solved. The balancing target is more accurate, the reliability and availability of the software function are improved, and the higher available charging and discharging energy of the vehicle is maintained on the basis of maintaining the consistency of the battery cells.

[0100] Figure 8 A schematic diagram of the structure of a vehicle provided in an embodiment of the present application. The vehicle may include:

[0101] A memory 801 , a processor 802 , and a computer program stored in the memory 801 and executable on the processor 802 .

[0102] When the processor 802 executes the program, the battery pack balancing method provided in the above embodiment is implemented.

[0103] Furthermore, the vehicle also includes:

[0104] The communication interface 803 is used for communication between the memory 801 and the processor 802 .

[0105] The memory 801 is used to store computer programs that can be executed on the processor 802 .

[0106] The memory 801 may include a high-speed RAM (Random Access Memory) memory, and may also include a non-volatile memory, such as at least one disk memory.

[0107] If the memory 801, the processor 802 and the communication interface 803 are implemented independently, the communication interface 803, the memory 801 and the processor 802 can be connected to each other through a bus and communicate with each other. The bus can be an ISA (Industry Standard Architecture) bus, a PCI (Peripheral Component Interconnect) bus or an EISA (Extended Industry Standard Architecture) bus, etc. The bus can be divided into an address bus, a data bus, a control bus, etc. For ease of representation, Figure 8 Only one thick line is used in the diagram, but this does not mean that there is only one bus or only one type of bus.

[0108] Optionally, in a specific implementation, if the memory 801, the processor 802 and the communication interface 803 are integrated on a chip, the memory 801, the processor 802 and the communication interface 803 can communicate with each other through an internal interface.

[0109] The processor 802 may be a CPU (Central Processing Unit), or an ASIC (Application Specific Integrated Circuit), or one or more integrated circuits configured to implement the embodiments of the present application.

[0110] An embodiment of the present application also provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the above-mentioned battery pack balancing method.

[0111] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic representations of the above terms are not necessarily directed to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or N embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0112] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include at least one of the features. In the description of this application, "N" means at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0113] Any process or method description in a flowchart or otherwise described herein may be understood to represent a module, fragment or portion of code comprising one or more executable instructions for implementing the steps of a custom logical function or process, and the scope of the preferred embodiments of the present application includes alternative implementations in which functions may not be performed in the order shown or discussed, including performing functions in a substantially simultaneous manner or in reverse order depending on the functions involved, which should be understood by technicians in the technical field to which the embodiments of the present application belong.

[0114] It should be understood that the various parts of the present application can be implemented by hardware, software, firmware or a combination thereof. In the above-mentioned embodiment, the N steps or methods can be implemented by software or firmware stored in a memory and executed by a suitable instruction execution system. For example, if implemented by hardware, as in another embodiment, it can be implemented by any one of the following technologies known in the art or their combination: a discrete logic circuit having a logic gate circuit for implementing a logic function for a data signal, a dedicated integrated circuit having a suitable combination of logic gate circuits, a programmable gate array, a field programmable gate array, etc.

[0115] A person skilled in the art may understand that all or part of the steps in the method for implementing the above-mentioned embodiment may be completed by instructing related hardware through a program, and the program may be stored in a computer-readable storage medium, which, when executed, includes one or a combination of the steps of the method embodiment.

[0116] Although the embodiments of the present application have been shown and described above, it can be understood that the above embodiments are exemplary and cannot be understood as limitations on the present application. Ordinary technicians in this field can change, modify, replace and modify the above embodiments within the scope of the present application.

Claims

1. A battery pack balancing method, characterized in that: The following steps are involved: Determine whether the current battery pack meets the preset offline balancing conditions; If the current battery pack meets the preset offline balancing condition, determining the target battery cell to be balanced in the current battery pack, the balancing time of the target battery cell, and the periodic wake-up duration; as well as The target battery cell is balanced according to the balancing time of the target battery cell, and the battery management system is controlled to enter the sleep mode, and the duration of the battery management system entering the sleep mode is obtained, and when the duration reaches the periodic wake-up duration, the battery management system is awakened, and whether the current battery pack meets the preset offline balancing condition is re-determined, until the current battery pack does not meet the preset offline balancing condition; The determining of the target battery cell to be balanced in the current battery pack, the balancing time of the target battery cell, and the periodic wake-up duration includes: Collecting current battery information and unit circuit information of the current battery pack; Calculate the voltage difference between each single cell and the minimum single cell based on the current battery information and the unit circuit information, and determine the target cell according to the voltage difference and an offline equalization voltage difference threshold, wherein the offline equalization voltage difference threshold is determined by the equalization capability of the battery management system and the consistency of the vehicle cells; The preset offline balancing condition includes that the open circuit voltage of the battery cell when being awakened has eliminated the polarization phenomenon.

2. The method according to claim 1, characterized in that The determining whether the current battery pack meets the preset offline balancing condition includes: Obtaining the current operating condition of the vehicle, the status information of the battery pack and the status information of the battery management system; If the current operating condition of the vehicle, the status information of the battery pack and the status information of the battery management system all meet their corresponding preset balancing conditions, it is determined that the current battery pack meets the preset offline balancing condition.

3. The method according to claim 1, characterized in that Before determining whether the current battery pack meets the preset offline balancing condition, the method further includes: Initializing the battery management system based on a preset initialization strategy; After the initialization is completed, the battery management system is self-checked based on a preset self-check strategy, and after the self-check is completed, the voltage and temperature of each single battery are periodically checked.

4. The method according to claim 3, characterized in that After obtaining the duration of the battery management system entering the sleep mode, the method further includes: Before the duration reaches the periodic wake-up duration, determining whether a wake-up instruction is received; If the wake-up instruction is received, the battery management system is initialized based on the preset initialization strategy.

5. A battery pack balancing device, characterized in that: include: A judgment module is used to judge whether the current battery pack meets the preset offline balancing conditions; A determination module, configured to determine, when the current battery pack meets the preset offline balancing condition, a target cell to be balanced in the current battery pack, a balancing time of the target cell, and a periodic wake-up duration; as well as A balancing module, used to balance the target battery cell according to the balancing time of the target battery cell, control the battery management system to enter a sleep mode, obtain the duration of the battery management system entering the sleep mode, and wake up the battery management system when the duration reaches the periodic wake-up duration, and re-determine whether the current battery pack meets the preset offline balancing condition; The determining module is further used for: Collecting current battery information and unit circuit information of the current battery pack; Calculate the voltage difference between each single cell and the minimum single cell based on the current battery information and the unit circuit information, and determine the target cell according to the voltage difference and an offline equalization voltage difference threshold, wherein the offline equalization voltage difference threshold is determined by the equalization capability of the battery management system and the consistency of the vehicle cells; The preset offline balancing condition includes that the open circuit voltage of the battery cell when being awakened has eliminated the polarization phenomenon.

6. The device according to claim 5, characterized in that The judging module is further used for: Obtaining the current operating condition of the vehicle, the status information of the battery pack and the status information of the battery management system; If the current operating condition of the vehicle, the status information of the battery pack and the status information of the battery management system all meet their corresponding preset balancing conditions, it is determined that the current battery pack meets the preset offline balancing condition.

7. A vehicle, characterized in that: include: A memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the program to implement the battery pack balancing method as described in any one of claims 1 to 4.

8. A computer-readable storage medium having a computer program stored thereon, characterized in that: The program is executed by a processor to implement the battery pack balancing method as described in any one of claims 1 to 4.

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