Battery pack balancing method, device, vehicle, and storage medium

Abstract

This application relates to the technical field of batteries, and in particular to a battery pack balancing method, device, vehicle, and storage medium. The method includes the steps of determining whether a current battery pack satisfies preset offline balancing conditions, and if the current battery pack satisfies the preset offline balancing conditions, determining a target cell to be balanced in the current battery pack, a balancing time for the target cell, and a periodic wake-up time length, balancing the target cell based on the balancing time for the target cell, controlling a battery management system to enter a sleep mode, and obtaining a duration for the battery management system to enter the sleep mode. When the duration reaches the periodic wake-up time length, waking up the battery management system and determining again whether the current battery pack satisfies the preset offline balancing conditions. This solves the problem in the related art of being unable to accurately determine the target cell to be balanced and being unable to maintain a balance between the consistency of the battery cells and the high energy of the vehicle, and makes the balancing target more accurate.

Description

[Technical Field]

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

[0002] Currently, the capacity of batteries used in electric vehicles is becoming larger and larger, and as the vehicle is used and the battery itself deteriorates, the consistency between cells in the battery is becoming increasingly worse.

[0003] The general balancing function, active balancing, or passive balancing, developed to ensure cell-to-cell consistency in batteries, either passively discharges or transfers energy between cells based on the difference in pressure or cell SOC (State of Charge) when the vehicle's battery management system wakes up. This method is mainly performed when the vehicle wakes up, and due to the capacity limitations of the balancing circuit itself, it is effective for batteries with a short number of safe hours, but for batteries with very large capacities, there is a limit to the operating time. For passenger cars, the total operating time per day is approximately 2 to 4 hours, so it does not achieve the purpose and is unable to ensure cell-to-cell consistency.

[0004] The conventional offline balancing technique developed based on this concept focuses on extending the balancing time. Before the main controller of the battery management system goes into sleep mode, the collection chip of the battery monitoring unit is activated to enter offline balancing mode and set the balancing cell, balancing time, and duty ratio. After that, the main controller goes into sleep mode, and the collection chip performs balancing on the cells to be balanced at the desired duty ratio based on the preset parameters until the set balancing time is reached. In this way, the running time of the balancing is bound by the running time of the vehicle system.

[0005] However, during operation, problems such as cell voltage polarization and SOC error can cause inaccurate calculation of balancing time, and if a serious fault occurs in the balancing circuit or collection circuit, the system will be unable to balance the corresponding cell or will incorrectly balance the target cell, affecting the balancing effect. At the same time, because offline balancing is performed in the sleep mode of the main controller unit, the cell collection unit in the battery does not have the ability to calculate or determine the system status, and therefore cannot respond immediately when an abnormal fault occurs, ultimately making it impossible to maintain high cell consistency. Summary of the Invention [Problem to be solved by the invention]

[0006] The present application provides a battery pack balancing method, device, vehicle, and storage medium, which solves problems in related art, such as the inability to accurately determine the target cells that need to be balanced, the inability to maintain a balance between the consistency of battery cells and the high energy of the vehicle, and erroneous judgments and balancing failures due to abnormal conditions. It also makes the balancing target more accurate, improves the reliability and availability of software functions, and maintains the consistency of battery cells while maintaining high usable charging and discharging energy of the vehicle. [Means for solving the problem]

[0007] An embodiment of a first aspect of the present application provides a battery pack balancing method, the battery pack balancing method including the steps of: determining whether a current battery pack satisfies a preset offline balancing condition; if the current battery pack satisfies the preset offline balancing condition, determining a target cell to be balanced in the current battery pack, a balancing time for the target cell, and a periodic wake-up time length; balancing the target cell based on the balancing time for the target cell, and controlling a battery management system to enter a sleep mode; obtaining a duration for the battery management system to enter the sleep mode; waking up the battery management system when the duration reaches the periodic wake-up time length; and determining again whether the current battery pack satisfies the preset offline balancing condition until the current battery pack does not satisfy the preset offline balancing condition.

[0008] Optionally, in some embodiments, the step of determining whether the current battery pack satisfies the preset offline balancing conditions includes the steps of obtaining a current operating state of the vehicle, state information of the battery pack, and state information of the battery management system, and determining that the current battery pack satisfies the preset offline balancing conditions if the current operating state of the vehicle, the state information of the battery pack, and the state information of the battery management system all satisfy their corresponding preset balancing conditions.

[0009] Optionally, in some embodiments, the step of determining a target cell to be balanced in the current battery pack, a balancing time for the target cell, and a periodic wake-up time length includes the steps of collecting current battery information and unit circuit information of the current battery pack, calculating a voltage difference between the voltage of each cell and the voltage of the smallest cell based on the current battery information and the unit circuit information, and determining the target cell based on the voltage difference and an offline balancing differential pressure threshold determined by the balancing capability of the battery management system and the consistency of cells in the vehicle.

[0010] Optionally, in some embodiments, the method further includes the steps of initializing the battery management system based on a preset initialization policy before determining whether the current battery pack satisfies the preset offline balancing condition, and self-testing the battery management system based on a preset self-test policy after completing the initialization, and periodically detecting the voltage and temperature of each of the cells after completing the self-test.

[0011] Optionally, in some embodiments, the method further includes determining whether a wake-up command is received after the battery management system obtains a duration length for entering a sleep mode and before the duration length reaches the periodic wake-up time length, and initializing the battery management system based on the preset initialization policy if the wake-up command is received.

[0012] An embodiment of a second aspect of the present application provides a battery pack balancing device, the battery pack balancing device including: a determination module for determining whether a current battery pack satisfies a preset offline balancing condition; a determination module for determining a target cell to be balanced in the current battery pack, a balancing time for the target cell, and a periodic wake-up time length when the current battery pack satisfies the preset offline balancing condition; and a balancing module for balancing the target cell based on the balancing time of the target cell, and controlling a battery management system to enter a sleep mode, obtaining a duration for the battery management system to enter the sleep mode, and waking up the battery management system when the duration reaches the periodic wake-up time length, and re-determining whether the current battery pack satisfies the preset offline balancing condition until the current battery pack does not satisfy the preset offline balancing condition.

[0013] Optionally, in some embodiments, the judgment module is further used for obtaining a current operating state of the vehicle, status information of the battery pack, and status information of the battery management system, and determining that the current battery pack satisfies the preset offline balancing condition if the current operating state of the vehicle, the status information of the battery pack, and the status information of the battery management system all satisfy their corresponding preset balancing conditions.

[0014] Optionally, in some embodiments, the determination module is further used to collect current battery information and unit circuit information of the current battery pack, and calculate a voltage difference between the voltage of each cell and the voltage of the smallest cell based on the current battery information and the unit circuit information, and determine the target cell based on the voltage difference and an offline balancing differential pressure threshold determined by the balancing capability of the battery management system and the consistency of cells in the vehicle.

[0015] Optionally, in some embodiments, before determining whether the current battery pack satisfies the preset offline balancing condition, the judgment module is further configured to initialize the battery management system based on a preset initialization policy, and after completing the initialization, perform a self-test of the battery management system based on a preset self-test policy, and after completing the self-test, periodically detect the voltage and temperature of each of the cells.

[0016] Optionally, in some embodiments, after obtaining the duration length for the battery management system to enter the sleep mode, the balancing module is further used for determining whether a wake-up command is received before the duration length has not reached the periodic wake-up time length, and if the wake-up command is received, initializing the battery management system based on the preset initialization policy.

[0017] An embodiment of a third aspect of the present application provides a vehicle, the vehicle including a memory, a processor, and a computer program stored in the memory and executable by the processor, the processor executing the computer program to realize the battery pack balancing method described in the above embodiment.

[0018] An embodiment of a fourth aspect of the present application provides a computer-readable storage medium having a computer program stored thereon, which is used to implement the battery pack balancing method described in the above embodiments by executing the computer program on a processor. [Effects of the Invention]

[0019] When the current battery pack satisfies the offline balancing conditions, the target cell to be balanced, the balancing time for the target cell, and the periodic wake-up time length are determined, and balancing is performed on the target cell based on the balancing time for the target cell. The battery management system is controlled to enter a sleep mode, and periodically wakes up the battery management system to determine again whether the current battery pack satisfies the offline balancing conditions until the current battery pack does not satisfy the offline balancing conditions. This solves the problems in the related art, such as the inability to accurately determine the target cell to be balanced, the inability to maintain a balance between the consistency of the battery cells and the high energy of the vehicle, and the occurrence of erroneous judgments and balancing failures due to abnormal conditions, and makes the balancing target more accurate, improves the reliability and availability of software functions, and maintains the consistency of the battery cells while maintaining high usable charging and discharging energy of the vehicle.

[0020] Additional aspects and advantages of the present application will be set forth in part in the description that follows, and in part will be obvious from the description, or may be learned by practice of the present application.

[0021] The above and / or additional aspects and advantages of the present application will become apparent and easier to understand from the following description of the embodiments taken in conjunction with the drawings. [Brief explanation of the drawings]

[0022] [Figure 1] 1 is a flowchart of a method for balancing a battery pack according to an embodiment of the present application. [Figure 2]4 is a flowchart for determining a target balancing cell according to one specific embodiment of the present application; [Figure 3] 3 is a flowchart of a battery pack location test according to one embodiment of the present application; [Figure 4] 1 is a MAP schematic diagram of a battery pack location test according to one embodiment of the present application; [Figure 5] 3 is a flowchart of calculating a pause time according to one specific embodiment of the present application; [Figure 6] 2 is a flowchart of a battery pack balancing method according to one embodiment of the present application; [Figure 7] 1 is a block diagram of a battery pack balancing device according to an embodiment of the present application; [Figure 8] 1 is a structural schematic diagram of a vehicle according to an embodiment of the present invention; DETAILED DESCRIPTION OF THE INVENTION

[0023] Hereinafter, the embodiments of the present application shown in the drawings will be described in detail, and in all the drawings, the same or similar reference numerals indicate the same or similar elements or elements having the same or similar functions. The embodiments described through the following reference drawings are illustrative and are intended to explain the present application, and should not be understood as limitations on the present application.

[0024]

[0013] In the following, a battery pack balancing method, device, vehicle, and storage medium according to embodiments of the present application will be described with reference to the accompanying drawings. In response to the problems described in the background art above, such as the inability to accurately determine target cells that need to be balanced, the inability to maintain a balance between the consistency of battery cells and the high energy of the vehicle, and the occurrence of erroneous judgments and balancing failures due to abnormal conditions, the present application provides a battery pack balancing method, which determines whether a vehicle satisfies offline balancing conditions, and if so, determines target cells that need to be balanced, a balancing time for the target cells, and a periodic wake-up time length, and balances the target cells based on the balancing time for the target cells, and controls a battery management system to enter a sleep mode, periodically wakes up the battery management system, and further determines whether the offline balancing conditions are met. This solves problems in related technologies, such as the inability to accurately determine the target cells that need to be balanced, the inability to maintain a balance between the consistency of the battery cells and the high energy of the vehicle, and erroneous judgments and balancing failures due to abnormal conditions.It makes the balancing target more accurate, improves the reliability and availability of software functions, and maintains the consistency of the battery cells while maintaining high usable charging and discharging energy of the vehicle.

[0025] Specifically, FIG. 1 is a flow chart of a battery pack balancing method according to an embodiment of the present application.

[0026] As shown in FIG. 1, the battery pack balancing method includes the following steps: In step S101, it is determined whether the current battery pack satisfies the preset offline balancing conditions.

[0027] Optionally, in some embodiments, determining whether the current battery pack satisfies the preset offline balancing conditions includes obtaining a current operating state of the vehicle, state information of the battery pack, and state information of the battery management system; and determining that the current battery pack satisfies the preset offline balancing conditions if the current operating state of the vehicle, the state information of the battery pack, and the state information of the battery management system all satisfy their corresponding preset balancing conditions.

[0028] The preset offline balancing conditions may be that the current operating state permits offline balancing and that there are no abnormalities in the battery pack status information and the battery management system status information. Here, the absence of abnormalities in the battery pack status information may include that the polarization phenomenon has been resolved when waking up the battery cell OCV (Open Circuit Voltage).

[0029] Furthermore, with the current high degree of vehicle electrification, vehicles experience a variety of operating conditions throughout their lifecycle, placing significant challenges on the reliability and availability of software functions. When a vehicle is running, problems such as loose connectors, poor contact in the collection harness, short or open circuits, and line degradation can affect the functionality of the main controller and collection unit. This can lead to inaccurate data collection in the collection unit, causing fluctuations up and down. It can take a certain amount of time for the main controller unit to perform logic judgments and issue fault warnings. Furthermore, it is necessary to consider the differentiation of different operating conditions that affect the initiation and operation of the system balancing function. Therefore, in the present embodiment, when the vehicle disconnects the relay and is in a relatively stable state, basic state detection is performed to determine whether the offline balancing initiation condition is met.

[0030] Specifically, the battery cell collection unit periodically collects and transmits cell voltages and temperatures to the main controller unit. The main controller unit performs function logic and state calculations based on the current system state and cell state information. The main controller unit then prepares for power-down hibernation. At this time, the main controller unit, through logic judgment, combines the cell voltages, cell temperatures, and collection board information input by the battery cell collection unit to determine whether offline balancing is supported in combination with the vehicle's current operating state, whether the battery pack state information and the battery management system state information are suitable for performing offline balancing, and comprehensively determine whether the preset offline balancing conditions are met. Here, the main controller unit may be the main logic control board of the battery management system, and the collection unit may be the cell voltage and temperature collection board of the battery management system, which simultaneously performs the balancing function. Specifically, if the vehicle's current operating state does not permit offline balancing, the system will not enter. If the system does not wake up the battery cell OCV to resolve the polarization phenomenon, the system will not enter. Considering the physical failure of the multi-point, if there are various abnormal failures in the battery system, such as a circuit failure of the collection circuit, a failure due to undervoltage of the cell, or an overtemperature failure, it may not be necessary to enter.

[0031] In step S102, if the current battery pack satisfies the preset offline balancing conditions, a target cell to be balanced in the current battery pack, a balancing time for the target cell, and a periodic wake-up time length are determined.

[0032] Optionally, in some embodiments, the step of determining a target cell to be balanced in the current battery pack, a balancing time for the target cell, and a periodic wake-up time length includes the steps of collecting current battery information and unit circuit information of the current battery pack, calculating a voltage differential between the voltage of each cell and the voltage of the smallest cell based on the current battery information and unit circuit information, and determining the target cell based on the voltage differential and an offline balancing differential pressure threshold determined by the balancing capability of the battery management system and the consistency of the cells in the vehicle.

[0033] Furthermore, since the cells are constantly charging and discharging while the vehicle is running, the OCV voltage and SOC cannot be accurately obtained, making it impossible to accurately determine the target cell for balancing.In this application, the current cell stops charging and discharging after an extreme operating state, and obtains the longest time parameter TOCV after the cell voltage has resolved the polarization phenomenon.The main controller unit starts timing after disconnecting the relay, and after the TOCV time, it collects the OCV voltage based on the current state information, corrects the SOC value, and determines the target cell for balancing.

[0034] Specifically, the main controller unit prepares for power-down hibernation and determines through logic judgment that it can activate the offline balancing function. Then, it determines the target cells that need to be balanced immediately and the corresponding balancing time, and calculates the time the system needs to hibernate. Specifically, as shown in FIG. 2, the main controller unit periodically calls the collection unit AFE (Active Front End) to collect current battery information and the circuit information of the collection unit. The main controller unit determines the differential voltage between each cell and the voltage of the smallest cell. The main controller unit compares the voltage differential voltage of each cell with a preset differential voltage threshold to determine the balancing target cell.

[0035] The setting of the preset balancing differential pressure threshold needs to take into account the system balancing capacity and the requirements for cell consistency in the vehicle, and the system balancing capacity needs to take into account the effective balancing current and balancing time of the balancing circuit (offline balancing time is controllable but smaller than the vehicle downtime). Effective balancing current x daily offline balancing time = maximum balancing capacity value / day, C offBalance year, The cell consistency requirement in a vehicle must take into account the vehicle's available charge / discharge energy under the current charge / discharge operating conditions after balancing.

[0036] It should be noted that the offline balancing differential pressure threshold in the embodiment of the present application may be determined based on the balancing capability of the battery management system and the consistency of the cells in the vehicle.

[0037] Specifically, as shown in FIG. 3, the embodiment of the present application can obtain the corresponding MAP relationship through testing, and then determine the offline balancing differential pressure threshold: t0: Initial environmental temperature of the battery pack test Stationary phase: T.1 Manufacture one or a small number of cells with a certain differential pressure D1mV from the current common cells at the battery pack level, and set the D1 value as shown in the MAP table in Figure 4. T.2 After the battery pack is stationary for T0 hours, the temperature of the battery pack and the ambient temperature are consistent. The main controller unit calculates the SOC accurately and collects a stable OCV.

[0038] Charging stages: T.3 Perform a full charge, record the charged energy value as Q1, and the final cell differential pressure as D2mV. Discharge stage: T.4 Perform a full discharge and record the released energy value as Q2, and the final cell differential pressure as D3mV. The specific method for full charge and full discharge tests can be based on the Chinese national standard GB / T31467.1 / .2, or can be defined by yourself. Here, the operations between charge and discharge, such as current control and rest, are not described here.

[0039] A MAP table as shown in Figure 4 is finally formed. Based on the above data, a relatively small offline balancing threshold is finally selected from the vehicle's accumulated full charge / full discharge cycle time based on the influence of the cell differential pressure on the vehicle's charge / discharge energy: C total =C offBalance xT Sleep xT interval Calculate as follows. where C total is the theoretical value of the balancing capacity, and T interval is the vehicle's accumulated full charge / full discharge energy time interval, in days, and T Sleep is the daily vehicle downtime, measured in hours, and C offBalance is the balancing maximum capacity value / day.

[0040] Based on the test data of the initial cell differential pressures D1, Q1 and Q2, determine the minimum cell voltage requirement that the vehicle can tolerate, and C total Based on the relationship between the initial cell voltage D1 and the off-line balancing trigger threshold, a threshold value within the balancing capability range is finally selected, where the off-line balancing trigger threshold can be slightly smaller than the vehicle target value to prevent the balancing judgment state from jumping.

[0041] Through certain tests, based on the relationship between the cell differential pressure and the charge / discharge energy in the vehicle, the cell differential pressure threshold D that needs to be maintained when the vehicle is parked is determined. refer In the actual project implementation process, the entry threshold D1 of offline balancing is D referIt can be made slightly smaller than. Since the current battery cell capacities are all very large, it is possible to balance about 1 Ah of power in only 10 hours, which is equivalent to about 1% SOC or a voltage difference of 8 - 10 mV. Therefore, the setting of the balancing cut-off voltage D2 is set to a relatively small value based on the self-wake-up cycle and balancing ability of the main controller unit, with D2 << D1 (much smaller), so that the controller cannot achieve this goal in one self-wake-up cycle.

[0042] Each self-wake-up cycle of the controller: Cell differential pressure D elta If OCV > D1, it meets the entry condition and further performs offline balancing on the cell differential pressure D elta If OCV < D1, it is smaller than the entry condition and does not perform offline balancing this time. This reduces the number of trigger times for offline balancing while effectively maintaining a high level of cell consistency over a long time, and the vehicle does not waste too much energy.

[0043] The balancing time of the target cell in the embodiment of the present application is calculated as follows: T offbalance = C(D trigger , D end ) / I Here, T offbalance is the target cell balancing time, C is the capacity that needs to be balanced for the target cell, D trigger is the offline balancing trigger differential pressure threshold, D end is the offline balancing differential pressure end threshold, and I is the balancing effective current.

[0044] D endThe threshold setting can be based on the requirement to reduce the vehicle's 12V power consumption, and can be set to a target value that cannot be achieved during the system's downtime. While this reduces the vehicle's power consumption, it also takes into account issues such as software multi-point expiration and memory area read / write problems, and after waking up from sleep, all parameters are reset and reused during the system initialization process. This eliminates the need to set other thresholds, reducing software complexity and improving software reliability.

[0045] The rest time is specifically set and the balancing target cell is set. In setting the balancing time, the main logic of calculating the rest time is shown in FIG.

[0046] S501, if there is heavy charging / discharging in the current operating state of the vehicle, set not to perform offline balancing this time, and set the next rest time to T polarization Set T polarization is the duration for which the polarization phenomenon of the cell OCV completely disappears. S502: Determine the wake-up source that will wake up this time, and determine whether the vehicle will wake up or whether it will self-wake up. S503, calculate the previous pause time, and the previous pause time is the parameter T polarization If it does, offline balancing can be performed for this pause. S504, if offline balancing is not performed this time, the next downtime is T polarization If offline balancing is performed this time, the next pause time is set to the periodic time T regular where the periodic time T regular This needs to be confirmed with the vehicle, and a time threshold is set based on the premise of reducing the power consumption of the vehicle's 12V power supply.

[0047] In step S103, balance the target cell based on the balancing time of the target cell, and control the battery management system to enter a sleep mode. Then, obtain a duration for the battery management system to enter the sleep mode. When the duration reaches a periodic wake-up time, wake up the battery management system and determine again whether the current battery pack meets the preset offline balancing conditions until the current battery pack does not meet the preset offline balancing conditions.

[0048] Those skilled in the art should understand that when the system performs offline balancing, the main controller unit is in a dormant state and does not perform any data calculations or logic processing, and if any faults such as circuit problems, collection unit chip problems, balancing circuit problems, or internal short circuits in the battery pack occur, more serious faults such as collected data drift, balancing circuit short circuits, and battery cell over-discharge will occur during the startup process of the balancing circuit, and the main controller unit will be unable to handle them.In the embodiment of the present application, after the main controller unit triggers the offline balancing function, it periodically wakes up and performs initialization to detect the overall system status and determine whether to perform further offline balancing.

[0049] Specifically, the main controller 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 sends it to the battery cell collection unit along with the corresponding balancing time. The battery cell collection unit sets the balancing target cell, the corresponding balancing time, and the balancing duty ratio according to the signal from the main controller unit, and writes them into the AFE register. The main controller unit goes to sleep, the RTC or SBC enters low power consumption mode and starts timing. The battery cell collection unit enters offline balancing mode and performs according to the duty ratio and time set for the target cell according to the information written in the register. After the main controller unit triggers the offline balancing function, it periodically wakes up and performs initialization to detect the status of the entire system and determine whether to perform further offline balancing.

[0050] Optionally, in some embodiments, the method further includes the steps of initializing the battery management system based on a preset initialization policy before determining whether the current battery pack satisfies a preset offline balancing condition, and self-testing the battery management system based on a preset self-test policy after completing the initialization, and periodically detecting the voltage and temperature of each battery cell after completing the self-test.

[0051] Here, the preset initialization policy and the preset self-test policy may be preset by related parties, and are not specifically limited here.

[0052] Specifically, before determining whether the current battery pack satisfies the preset offline balancing condition, the battery management system is initialized. 1. The main controller unit is woken up, systematically performs the initialization of the whole system, and initializes the collection unit of the battery cell. 2. The collection unit of the battery cell is initialized, the offline balancing function is stopped, the collection unit and the main controller unit are started, communication is established between the collection unit and the main controller unit, and the collection of the cell voltage and temperature is started. 3. The main controller unit initiates a self-test of the entire system to detect the current system software and hardware status, including the status of hardware chips, circuits, and various collection lines and sensors. 4. The initialization of the battery cell collection unit is completed, and the cell voltage and temperature are periodically collected and transmitted to the main controller unit. 5. The main controller unit starts to operate normally and periodically detects and judges the cell voltage and temperature.

[0053] Optionally, in some embodiments, the method further includes determining whether a wake-up command is received after the battery management system obtains the duration length for entering the sleep mode and before the duration length reaches the periodic wake-up time length, and initializing the battery management system based on a preset initialization policy if a wake-up command is received.

[0054] In the actual execution process, the vehicle may receive other wake-up methods besides periodic self-wake-up, such as user wake-up, and determine whether a wake-up command is received before the duration length reaches the periodic wake-up time length. If a wake-up command is received, further determine whether the battery management system needs to be initialized and offline balancing needs to be performed based on a preset initialization policy.

[0055] In order to allow those skilled in the art to further understand the battery pack balancing method according to the embodiment of the present disclosure, the following detailed description will be given in conjunction with specific examples.

[0056] As shown in FIG. 6, FIG. 6 is a battery pack balancing method according to an embodiment of the present application.

[0057] The main controller unit initializes the system state and initializes the collection unit, which stops its offline function and performs initialization. The main controller unit performs a system self-test. The collection unit completes the collection of battery cell voltages and temperatures and transmits the collected battery voltages and temperatures to the main controller unit. The main controller unit runs the system, periodically detects cell voltages and temperatures and performs logic and calculations based on the current state, starts offline balancing, calculates offline balancing cells and time, calculates the pause time, sets the pause time, sets the balancing target cells, sets the balancing time, and transmits the set balancing cells and time to the collection unit, which writes it to the AFE register. The main controller unit pauses and the collection unit enters offline balancing.

[0058] This allows the main controller unit to disconnect the relay, then time the TOCV. After the polarization voltage is eliminated, it again collects cell voltages for balancing judgment. At this time, the polarization phenomenon during cell charging and discharging has disappeared, making the acquired cell OCV voltage more accurate and achieving a more accurate balancing target. The main controller unit determines whether to perform offline balancing after the vehicle disconnects the relay, the cells are in a stable state, and the system basic status is detected. It also periodically self-wakes up to detect the status of the system's software and hardware, improving circuit fault detection coverage. This allows the controller to avoid circuit degradation and other accidental failures, and prevents balancing failures caused by circuit problems. Multi-point failure analysis improves the reliability and availability of software functions.

[0059] According to the battery pack balancing method of the present application, the method determines whether a vehicle satisfies offline balancing conditions, and if so, determines a target cell to be balanced, a balancing time for the target cell, and a periodic wake-up time length. Based on the balancing time for the target cell, the method balances the target cell, controls the battery management system to enter a sleep mode, and periodically wakes up the battery management system to further determine whether the offline balancing conditions are met. This solves the problems of the related art, such as the inability to accurately determine the target cell to be balanced, the inability to maintain a balance between the consistency of the battery cells and the high energy requirements of the vehicle, and false judgments and balancing failures due to abnormal conditions. This method achieves a more accurate balancing target, improves the reliability and availability of software functions, and maintains the consistency of the battery cells while maintaining high usable charging and discharging energy for the vehicle.

[0060] Next, a battery pack balancing device according to an embodiment of the present invention will be described with reference to the drawings.

[0061] FIG. 7 is a block diagram of a battery pack balancing device according to an embodiment of the present invention.

[0062] As shown in FIG. 7, the battery pack balancing device 10 includes a judging module 100, a determining module 200 and a balancing module 300. The judgment module 100 is used to determine whether the current battery pack meets the preset offline balancing conditions. The determination module 200 is used to determine a target cell to be balanced in the current battery pack, a balancing time for the target cell, and a periodic wake-up time length if the current battery pack meets the preset offline balancing conditions. The balancing module 300 is used to balance the target cell based on the balancing time of the target cell, and control the battery management system to enter a sleep mode. The balancing module 300 obtains the duration of the battery management system entering the sleep mode. When the duration reaches the periodic wake-up time length, the battery management system is woken up, and the current battery pack is again used to determine whether the current battery pack meets the preset offline balancing conditions until it does not meet the preset offline balancing conditions.

[0063] Optionally, in some embodiments, the judgment module 100 is further used to obtain the current operating state of the vehicle, the state information of the battery pack, and the state information of the battery management system, and determine that the current battery pack satisfies the preset offline balancing condition if the current operating state of the vehicle, the state information of the battery pack, and the state information of the battery management system all satisfy their corresponding preset balancing conditions.

[0064] Optionally, in some embodiments, the determination module 200 is further used to collect current battery information and unit circuit information of the current battery pack, and calculate a voltage difference between the voltage of each cell and the voltage of the smallest cell based on the current battery information and unit circuit information, and determine a target cell based on the voltage difference and an offline balancing differential pressure threshold determined by the balancing capability of the battery management system and the consistency of the cells in the vehicle.

[0065] Optionally, in some embodiments, before determining whether the current battery pack satisfies the preset offline balancing condition, the judgment module 200 is further used to initialize the battery management system according to a preset initialization policy, and after completing the initialization, to self-test the battery management system according to a preset self-test policy, and after completing the self-test, to periodically detect the voltage and temperature of each battery cell.

[0066] Optionally, in some embodiments, after obtaining the duration for the battery management system to enter sleep mode, the balancing module 300 is further used to determine whether a wake-up command is received before the duration has reached the periodic wake-up time length, and if a wake-up command is received, to initialize the battery management system based on a preset initialization policy.

[0067] The explanations and descriptions of the battery pack balancing method according to the embodiment may be applied to the battery pack balancing device of the embodiment, and will be omitted here.

[0068] The battery pack balancing device according to the embodiment of the present application determines whether a vehicle satisfies offline balancing conditions, and if so, determines a target cell to be balanced, a balancing time for the target cell, and a periodic wake-up time length, and balances the target cell based on the balancing time for the target cell, controls the battery management system to enter a sleep mode, and periodically wakes up the battery management system to further determine whether the offline balancing conditions are met. This solves the problems of the related art, such as the inability to accurately determine the target cell to be balanced, the inability to maintain a balance between the consistency of the battery cells and the high energy requirements of the vehicle, and false judgments and balancing failures due to abnormal conditions, and improves the accuracy of the balancing target, improves the reliability and availability of software functions, and maintains the consistency of the battery cells while maintaining high usable charging and discharging energy of the vehicle.

[0069] FIG. 8 is a structural schematic diagram of a vehicle according to an embodiment of the present invention. The system may include a memory 801, a processor 802, and a computer program stored in the memory 801 and operable on the processor 802. When the processor 802 executes the program, it implements the battery pack balancing method according to the above embodiment.

[0070] Furthermore, the vehicle It further includes a communication interface 803 used for communication between the memory 801 and the processor 802 . The memory 801 is used to store a computer program that can be run by the processor 802 . The memory 801 may include high speed RAM (Random Access Memory) memory, and may further include non-volatile memory, for example at least one disk memory.

[0071] When the memory 801, processor 802, and communication interface 803 are implemented independently, the communication interface 803, memory 801, and processor 802 are interconnected via a bus to complete communication between them. The bus may be an ISA (Industry Standard Architecture) bus, a PCI (Peripheral Component Interconnect) bus, or an EISA (Extended Industry Standard Architecture) bus. The bus may be divided into an address bus, a data bus, a control bus, etc. For convenience, only thick lines are shown in Figure 8, but this does not indicate that there is only one bus or only one type of bus.

[0072] Optionally, in a specific implementation, if the memory 801, the processor 802 and the communication interface 803 are integrated into one chip, the memory 801, the processor 802 and the communication interface 803 can complete communication with each other through an internal interface.

[0073] Processor 802 may be a CPU (Central Processing Unit), or may be an ASIC (Application Specific Integrated Circuit), or may be one or more integrated circuits configured to implement embodiments of the present application.

[0074] An embodiment of the present application further provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, realizes the above-described battery pack balancing method.

[0075] In the description herein, the reference terms "one embodiment," "some embodiments," "examples," "specific examples," or "some examples" mean that the specific features, structures, materials, or characteristics described in combination with the embodiment or example are included in at least one embodiment or example of the present application. In the description herein, exemplary descriptions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any one or N embodiments or examples in an appropriate manner. Furthermore, those skilled in the art may combine and combine different embodiments or examples and features of different embodiments or examples described herein, as long as they are not mutually inconsistent.

[0076] Furthermore, the terms "first" and "second" are used for descriptive purposes only and cannot be understood to indicate or imply relative importance or the number of technical features indicated. Therefore, a feature qualified as "first" or "second" may explicitly or implicitly include at least one such feature. In the description of this application, "N" means at least two, e.g., two, three, etc., unless otherwise specifically limited.

[0077] Any process or method description depicted in a flowchart or otherwise described herein may be understood as a module, segment, or portion thereof representing code comprising one or N executable instructions for implementing a customized logical function or process step, and the scope of the preferred embodiments of the present application includes alternative implementations where functions need not be performed in the order shown or discussed, and with related functions, essentially simultaneously or in reverse order, as will be understood by those skilled in the art of the present application.

[0078] It should be understood that each part of the present application may be realized by hardware, software, firmware, or a combination thereof. In the above embodiment, the N steps or methods may be realized by software or firmware stored in a memory and executed by an appropriate instruction execution system. For example, when realized by hardware, as in the other embodiments, the hardware may be realized by any of techniques known in the art, such as a discrete logic circuit having logic circuits for implementing logical functions on data signals, a dedicated integrated circuit having appropriate combinational logic circuits, a programmable gate array, a field programmable gate array, or a combination thereof.

[0079] Those skilled in the art can understand that all or part of the steps performed by the method for realizing the above embodiments can be completed by instructing relevant hardware through a program, and the program may be stored in a computer-readable storage medium, which includes one or a combination of the steps of the method embodiments when executed.

[0080] Although the embodiments of the present application have been shown and described above, the above embodiments are illustrative and should not be construed as limiting the present application, and a person skilled in the art may change, modify, substitute, and alter the above embodiments within the scope of the present application. [CROSS-REFERENCE TO RELATED APPLICATIONS]

[0081] This application is based on and claims priority from a Chinese patent application bearing application number CN202310105523.1 and filed on January 29, 2023, the entire contents of which are incorporated herein by reference. [Explanation of symbols]

[0082] 10 Balancing device, 100 Judgment module, 200 Decision module, 300 Balancing module, 801 Memory, 802 Processor, 803 Communication interface

Claims

1. A method for balancing a battery pack, comprising: determining whether the current battery pack satisfies a preset offline balancing condition; If the current battery pack satisfies the preset offline balancing condition, determining a target cell to be balanced in the current battery pack, a balancing time for the target cell, and a periodic wake-up time length; performing balancing on the target cell based on a balancing time of the target cell and controlling a battery management system to enter a sleep mode; obtaining a duration length for the battery management system to enter the sleep mode, and waking up the battery management system when the duration length reaches the periodic wake-up time length; and determining again whether the current battery pack satisfies the preset offline balancing condition until the current battery pack does not satisfy the preset offline balancing condition.

2. The step of determining whether the current battery pack satisfies the preset offline balancing condition includes: acquiring a current operating state of the vehicle, state information of the battery pack, and state information of the battery management system; and determining that the current battery pack satisfies the preset offline balancing condition when the current operating state of the vehicle, the state information of the battery pack, and the state information of the battery management system all satisfy the corresponding preset balancing condition.

3. The step of determining a target cell to be balanced in the current battery pack, a balancing time for the target cell, and a periodic wake-up time length includes: collecting current battery information and unit circuit information of the current battery pack; 2. The battery pack balancing method of claim 1, further comprising: calculating a voltage difference between a voltage of each cell and a voltage of a smallest cell based on the current battery information and the unit circuit information; and determining the target cell based on the voltage difference and an offline balancing differential pressure threshold determined by the balancing capability of the battery management system and the consistency of cells in the vehicle.

4. before determining whether the current battery pack satisfies the preset offline balancing condition; initializing the battery management system based on a preset initialization policy; 4. The battery pack balancing method of claim 3, further comprising: after completing the initialization, performing a self-test on the battery management system according to a preset self-test policy; and after completing the self-test, periodically detecting the voltage and temperature of each of the cells.

5. After the battery management system obtains the duration of entering the sleep mode, determining whether a wake-up command is received before the duration length has reached the periodic wake-up time length; 5. The battery pack balancing method according to claim 4, further comprising: initializing the battery management system based on the preset initialization policy when the wake-up command is received.

6. A battery pack balancing device, comprising: a determination module for determining whether the current battery pack satisfies a preset offline balancing condition; a determination module for determining a target cell to be balanced in the current battery pack, a balancing time for the target cell, and a periodic wake-up time length when the current battery pack satisfies the preset offline balancing condition; a balancing module for performing balancing on the target cell based on a balancing time of the target cell and controlling a battery management system to enter a sleep mode, obtaining a duration length for the battery management system to enter the sleep mode, waking up the battery management system when the duration length reaches the periodic wake-up time length, and again determining whether the current battery pack satisfies a preset offline balancing condition.

7. The determination module further comprises: Obtaining a current operating state of the vehicle, status information of the battery pack, and status information of the battery management system; and 7. The battery pack balancing device of claim 6, wherein when the current operating state of the vehicle, the state information of the battery pack, and the state information of the battery management system all satisfy the corresponding predetermined balancing conditions, the battery pack is determined to satisfy the predetermined offline balancing conditions.

8. The decision module further comprises: collecting current battery information and unit circuit information of the current battery pack; and 7. The battery pack balancing device according to claim 6, further comprising: calculating a voltage difference between the voltage of each cell and the voltage of a minimum cell based on the current battery information and the unit circuit information; and determining the target cell based on the voltage difference and an offline balancing differential pressure threshold determined by the balancing capability of the battery management system and the consistency of cells in a vehicle.

9. A vehicle comprising a memory, a processor, and a computer program stored in the memory and executable by the processor, wherein the processor executes the battery pack balancing method according to any one of claims 1 to 5 by executing the computer program.

10. A computer-readable storage medium having a computer program stored therein, the computer program being used to realize the battery pack balancing method according to any one of claims 1 to 5 when executed by a processor.

Images