A battery equalization method, system and automobile

Abstract

The present disclosure relates to the technical field of battery active balancing, and provides a battery balancing method, a system and an automobile. The method comprises the following steps: when receiving a balancing instruction, repeatedly performing the following steps until receiving a stop balancing instruction: controlling a selected battery to be discharged in a battery pack to charge a super capacitor through a bidirectional synchronous BUCK; monitoring the state of the super capacitor during the charging process; if the super capacitor reaches a target charging state, controlling the super capacitor to charge a selected battery to be charged in the battery pack through the bidirectional synchronous BUCK; monitoring the state of the super capacitor during the discharging process; and if the super capacitor reaches a target discharging state, controlling the bidirectional synchronous BUCK to stop working. The active balancing scheme of the present application not only reduces the system cost, but also effectively improves the system balancing efficiency and overall conversion efficiency because the bidirectional synchronous BUCK circuit is used as the energy conversion circuit for battery balancing.

Description

Technical Field

[0001] This application relates to the field of battery balancing technology, and more particularly to a battery balancing method, system, and automobile. Background Technology

[0002] In battery pack applications, variations in the manufacturing process of individual battery cells, as well as differences in environmental stress, can lead to inconsistent charge levels. This can result in decreased battery pack performance and a shortened lifespan. Therefore, achieving charge balance among individual battery cells is a crucial means to improve battery pack performance and lifespan.

[0003] In large-scale energy storage systems, because individual battery cells typically have large capacities, passive balancing methods, which suffer from low balancing current, significant energy waste, and slow balancing speed, are generally not feasible. Active balancing is therefore employed instead. However, due to its high cost, it is rarely used in actual automotive products. Furthermore, some discrete solutions are also not widely adopted due to their low efficiency and complex control. Summary of the Invention

[0004] In view of this, embodiments of the present disclosure provide a battery balancing method, system, and vehicle to solve the technical problem of how to perform power balancing of individual battery cells in a large energy storage system in a low-cost and efficient active balancing manner.

[0005] A first aspect of this disclosure provides a battery balancing method applied in a circuit where a battery pack and a supercapacitor are respectively connected to at least two sides of a bidirectional synchronous BUCK. The active battery balancing method includes: upon receiving a balancing command, repeatedly executing the following steps until a stop balancing command is received: controlling a selected battery in the battery pack to charge the supercapacitor through the bidirectional synchronous BUCK; monitoring the state of the supercapacitor during charging; if the supercapacitor reaches a target charging state, controlling the supercapacitor to charge the selected battery in the battery pack through the bidirectional synchronous BUCK; monitoring the state of the supercapacitor during discharging; if the supercapacitor reaches a target discharging state, controlling the bidirectional synchronous BUCK to stop operating.

[0006] A second aspect of this disclosure provides a battery equalization system, including: a battery gating module, a supercapacitor module, a bidirectional synchronous BUCK module, and a controller. The battery gating module and the supercapacitor module are respectively connected to both sides of the bidirectional synchronous BUCK module. The battery gating module is used to connect to a battery pack. The controller is connected to the battery gating module, the supercapacitor module, and the bidirectional synchronous BUCK module. The controller includes at least a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, it implements the steps of the above-described method.

[0007] A third aspect of this disclosure provides an automobile including a power battery comprising multiple battery packs, each battery pack consisting of multiple battery cells. The automobile also includes the aforementioned battery balancing system, which is connected to at least one battery pack of the power battery.

[0008] The beneficial effects of this disclosed embodiment compared to the prior art are as follows: The battery balancing method, upon receiving a balancing command, repeatedly executes the following steps until a stop balancing command is received: controlling the selected batteries in the battery pack to charge the supercapacitor via a bidirectional synchronous BUCK; monitoring the state of the supercapacitor during charging; if the supercapacitor reaches the target charging state, controlling the supercapacitor to charge the selected batteries in the battery pack via the bidirectional synchronous BUCK; monitoring the state of the supercapacitor during discharging; if the supercapacitor reaches the target discharging state, controlling the bidirectional synchronous BUCK to stop working. Since this method is applied to a discrete balancing control circuit where at least the battery pack and supercapacitor are connected to both sides of the bidirectional synchronous BUCK respectively, system costs are reduced. Furthermore, using the bidirectional synchronous BUCK circuit as the energy conversion circuit for battery balancing, compared to a conventional BUCK circuit, can effectively improve system balancing efficiency and overall conversion efficiency without significantly increasing control complexity. Attached Figure Description

[0009] To more clearly illustrate the technical solutions in the embodiments of this disclosure, the accompanying drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this disclosure. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0010] Figure 1 This is a schematic flowchart of a battery balancing method provided in an embodiment of this disclosure;

[0011] Figure 2 This is a schematic diagram of the architecture of a battery balancing system provided in an embodiment of this disclosure;

[0012] Figure 3 This is a schematic diagram of the circuit principle of a bidirectional synchronous BUCK module provided in an embodiment of this disclosure;

[0013] Figure 4 This is a schematic diagram of the circuit principle of a battery selection module provided in an embodiment of this disclosure;

[0014] Figure 5 This is a schematic diagram of the circuit principle of a supercapacitor provided in an embodiment of this disclosure;

[0015] Figure 6This is a schematic diagram of the structure of a controller provided in an embodiment of this disclosure;

[0016] Figure 7 This is a partial structural diagram of a car provided in an embodiment of this disclosure. Detailed Implementation

[0017] In the following description, specific details such as particular system architectures and techniques are set forth for illustrative purposes and not for limitation, so as to provide a thorough understanding of the embodiments of this disclosure. However, those skilled in the art will understand that this disclosure may also be implemented in other embodiments without these specific details. In other instances, detailed descriptions of well-known systems, apparatuses, circuits, and methods have been omitted so as not to obscure the description of this disclosure with unnecessary detail.

[0018] See Figure 1 In the first embodiment of this application, a battery balancing method is provided, applied in a circuit where a battery pack and a supercapacitor are respectively connected to at least two sides of a bidirectional synchronous BUCK. This active battery balancing method includes: upon receiving a balancing command, repeatedly executing the following steps until a stop balancing command is received:

[0019] S101 controls the selected undischarged batteries in the battery pack to charge the supercapacitor through bidirectional synchronous BUCK.

[0020] S102 monitors the status of the supercapacitor during charging;

[0021] S103, if the supercapacitor reaches the target charging state, control the supercapacitor to charge the selected battery in the battery pack through bidirectional synchronous BUCK.

[0022] S104 monitors the state of the supercapacitor during the discharge process;

[0023] S105: If the supercapacitor reaches the target discharge state, control the bidirectional synchronous BUCK to stop working.

[0024] Here, BUCK describes a specific voltage conversion topology that can reduce a higher input voltage to a lower output voltage; therefore, it is also called a buck converter. Specifically, it is a DC-DC converter that uses inductors, capacitors, and other components to achieve voltage conversion by controlling the on / off state of switching elements, featuring high efficiency and low power consumption. In this embodiment, the bidirectional synchronous BUCK is an improved BUCK converter that can not only step down but also operate in reverse to achieve a boost function. This bidirectionality allows it to convert voltage in both directions for charging and discharging the battery pack and supercapacitor connected to both sides of the bidirectional synchronous BUCK, achieving battery equalization. "Synchronous" refers to the use of synchronous rectification technology instead of traditional diode rectification to improve efficiency. Synchronous rectification uses low-loss switching devices such as MOSFETs to replace diodes, thereby reducing losses and improving overall conversion efficiency.

[0025] For example, in a battery balancing application scenario, see... Figure 2 and Figure 3 The bidirectional synchronous BUCK includes at least four MOSFETs and one inductor L. The four MOSFETs are designated Q1, Q2, Q3, and Q4, and are divided into two groups, each containing two MOSFETs (one upper and one lower). Specifically, Q1 and Q2 are located on one side of the circuit, forming one group, for connecting the battery pack. A battery selection module is also connected between the battery pack and the side of the circuit containing Q1 and Q2. Q3 and Q4 are located on the other side of the circuit, forming another group, for connecting the supercapacitor. One end of the inductor L is connected to the common node connecting Q1 and Q2, and the other end of the inductor L is connected to the common node connecting Q3 and Q4. When the battery cells in the battery pack need to charge the supercapacitor, this is achieved by controlling switches Q1 and Q2; when the supercapacitor needs to discharge the battery cells in the battery pack, this is achieved by controlling switches Q3 and Q4.

[0026] The aforementioned active battery balancing method uses a bidirectional synchronous BUCK circuit as the energy conversion circuit for battery balancing. Taking advantage of the bidirectional synchronous BUCK circuit's ability to switch voltage in two directions, it transfers battery power to a supercapacitor for a selected discharging battery, and then transfers the power stored in the supercapacitor to a selected recharging battery, thereby achieving battery power balancing. Since the bidirectional synchronous BUCK circuit uses low-loss MOSFETs instead of diodes in traditional BUCK circuits, it effectively improves system balancing efficiency and overall energy conversion efficiency without significantly increasing control complexity.

[0027] In some optional embodiments, step S101, controlling the selected battery to be discharged in the battery pack to charge the supercapacitor through the bidirectional synchronous BUCK, includes: controlling the battery selection module to select the battery to be discharged; controlling the supercapacitor to switch to parallel mode; and controlling the bidirectional synchronous BUCK to form a working state in which the battery to be discharged discharges to the supercapacitor.

[0028] Combination Figure 2 In general, when selecting batteries to be discharged, a battery selection module can be used to select the individual battery cells to which energy should be transferred to the supercapacitor. In practical applications, the specific implementation of the battery selection module is not unique. For example, the battery selection module consists of multiple MOSFETs or relays, forming a switching matrix to selectively connect different battery packs and individual battery cells within those packs. When energy needs to be transferred from a specific battery to the supercapacitor, the battery selection module selects the target battery cell within that battery pack and activates the corresponding MOSFET, connecting the target battery cell to the bidirectional synchronous BUCK circuit to begin energy transfer. Conversely, when energy needs to be transferred from the supercapacitor to another battery, the battery selection module disconnects the current battery cell and switches to another target battery cell to complete charging or energy recirculation.

[0029] The selection of which battery cell in the battery pack to be discharged by the battery selection module is controlled by a controller (e.g., MCU) that sends equalization commands. The controller can select the battery to be discharged according to a predetermined battery selection strategy and send a corresponding first selection command to the battery selection module. This first selection command can be included in the equalization command or sent together with the equalization command. The battery selection module responds to the first selection command by turning on the corresponding MOSFET switch to connect the corresponding target battery cell to the bidirectional synchronous BUCK circuit and start energy transfer.

[0030] A supercapacitor consists of multiple capacitor units. A control circuit controls these units to be connected in series on one side of a bidirectional synchronous BUCK capacitor, or to be connected in parallel on the same side. In this embodiment, when a battery to be discharged is selected to transfer energy to the supercapacitor, the capacitor units in the supercapacitor are connected in parallel, making the voltage on the battery side higher than the voltage on the supercapacitor side. This allows the battery's charge to be transferred to the supercapacitor via the bidirectional synchronous BUCK, charging the supercapacitor. When a battery to be recharged is selected to receive energy returned from the supercapacitor, the capacitor units in the supercapacitor are connected in series, making the voltage on the supercapacitor side higher than the voltage on the battery side. This allows the stored charge in the supercapacitor to be transferred to the battery to be recharged via the bidirectional synchronous BUCK, charging the battery.

[0031] After selecting the battery to be discharged and controlling the supercapacitor in parallel mode, the MOSFET switches Q3 and Q4 in the bidirectional synchronous BUCK circuit are turned off, and switches Q1 and Q2 are controlled to charge the supercapacitor from the battery to be discharged.

[0032] During the charging process of the supercapacitor from the battery to be discharged, the voltage of the supercapacitor is monitored. When the supercapacitor is charged to the target state, the bidirectional synchronous BUCK is controlled to stop working.

[0033] In some optional implementations, step S102, monitoring the state of the supercapacitor during charging includes: monitoring whether the voltage of the supercapacitor rises to a preset first voltage threshold; if the supercapacitor rises to the first voltage threshold, controlling the bidirectional synchronous BUCK to stop working;

[0034] If the supercapacitor does not rise to the first voltage threshold, continue to control the bidirectional synchronous BUCK to charge the supercapacitor from the battery to be discharged, and continuously monitor whether the voltage of the supercapacitor rises to the preset first voltage threshold.

[0035] Specifically, when the battery to be discharged charges the supercapacitor, the voltage of each capacitor cell in the supercapacitor will increase. Since the supercapacitor is in a state of parallel connection of multiple capacitor cells, it charges multiple capacitor cells in parallel. When the voltage of each capacitor cell reaches the first voltage threshold, charging of the supercapacitor stops. At this time, the sum of the voltages of each capacitor cell in the supercapacitor should be greater than the voltage of the battery to be charged later in order to ensure that the battery to be charged is charged in reverse later.

[0036] For example, in one application scenario, the rated voltage of a single battery cell in the battery pack is 3.8V, and the supercapacitor consists of 3 capacitor cells. The first voltage threshold is preferably 2.6V. When the bidirectional synchronous BUCK is controlled to charge the supercapacitor from the battery to be discharged, the voltage of the capacitor cell begins to rise. At the same time, the voltage of the capacitor cell is monitored. If the voltage of the capacitor cell reaches 2.6V, the bidirectional synchronous BUCK continues to work to charge the capacitor cell. If the voltage of the capacitor cell reaches 2.6V, the bidirectional synchronous BUCK stops working. At this time, the sum of the voltages of the two capacitor cells is 2.6*3=7.8V, which is much higher than the voltage of the single battery cell in the battery pack.

[0037] After the battery to be discharged has finished charging the supercapacitor, a battery to be charged will be selected, and the supercapacitor will be controlled to switch to series mode, so that the capacitor units in the supercapacitor are connected in series, so as to control the bidirectional synchronous BUCK circuit to make the supercapacitor discharge to the battery to be charged, thereby completing a battery power balancing cycle.

[0038] In some optional embodiments, when the voltage of the capacitor cell in the supercapacitor reaches a first voltage threshold, step S103, controlling the supercapacitor to charge the selected battery in the battery pack through the bidirectional synchronous BUCK, includes: controlling the battery selection module to select the battery to be charged; controlling the supercapacitor to switch to series mode; and controlling the bidirectional synchronous BUCK to form a working state in which the supercapacitor discharges to the battery to be charged.

[0039] Specifically, a battery selection module selects a single battery cell as the battery to be recharged. The voltage of the battery to be recharged is generally significantly lower than the voltage of the battery to be discharged before discharge. The charge transferred from the battery to be discharged to the supercapacitor is used to charge the battery to be recharged, thereby achieving the effect of battery power balance in the battery pack. The principle of selecting the battery to be recharged is the same as that of selecting the battery to be charged. Since the specific implementation method of selecting the battery to be charged has been described in detail above, it will not be repeated here.

[0040] Combination Figure 2 In this process, when the supercapacitor discharges to the rechargeable battery, the MOSFET switches Q1 and Q2 in the bidirectional synchronous BUCK circuit are turned off, and switches Q3 and Q4 are controlled to allow the supercapacitor to discharge to the rechargeable battery.

[0041] During the discharge process of the supercapacitor, it is also necessary to monitor the voltage of each capacitor cell in the supercapacitor to ensure that the voltage on the supercapacitor side is higher than the voltage of the battery that needs to be recharged.

[0042] In some optional embodiments, step S104, monitoring the state of the supercapacitor during the discharge process includes: monitoring whether the voltage of the supercapacitor drops to a preset second voltage threshold, the second voltage threshold being less than a first voltage threshold; if the supercapacitor drops to the second voltage threshold, controlling the bidirectional synchronization BUCK to stop working; if the supercapacitor does not drop to the second voltage threshold, continuing to control the bidirectional synchronization BUCK to enable the supercapacitor to charge the battery that needs to be charged, and continuously monitoring whether the voltage of the supercapacitor drops to the preset second voltage threshold.

[0043] The second voltage threshold is the voltage threshold of the capacitor unit in the supercapacitor. Since the capacitor units are connected in series when the supercapacitor is discharging, the voltage of the capacitor unit will gradually decrease as the discharge progresses, while the voltage of the rechargeable battery will gradually increase. However, it is still necessary to ensure that the sum of the voltages of all the capacitor units connected in series is greater than the voltage of the rechargeable battery in order to ensure the normal discharge process.

[0044] Preferably, the second voltage threshold is 1.45V. For example, in one application scenario, suppose the supercapacitor contains three capacitor cells and there is a battery pack consisting of three individual cells (Cell A, Cell B, and Cell C), wherein:

[0045] The voltage of Cell A is 3.8V;

[0046] The voltage of Cell B is 3.6V;

[0047] The voltage of Cell C is 3.7V.

[0048] use Figure 2 The capacitor balancing circuit shown is used to make the voltage of each battery cell in the battery pack more consistent. Assume that the balancing command is used to control CEL1A to discharge to CELLB. Then, battery cell CEL1A is first connected to one side of the bidirectional synchronous BUCK circuit, and the three capacitor units are connected in parallel to the other side of the bidirectional synchronous BUCK circuit. The bidirectional synchronous BUCK circuit is controlled to make battery cell CELLA charge the capacitor units and charge them to the first voltage threshold of 2.6V. Once the capacitor cells are charged to 2.6V, the connection between the battery cell CellB (3.6V) and the bidirectional synchronous BUCK circuit is switched, and the capacitor cells are connected in series. The bidirectional synchronous BUCK circuit then controls the capacitor cells to charge the battery cell CellB. Initially, the sum of the voltages of the three capacitor cells is 2.6*3 = 7.8V, which is much greater than CellB (3.6V). Therefore, the capacitor cells discharge into CellB. As the discharge progresses, the voltage of the capacitor cells decreases, while the voltage of CellB increases. When the voltage of the capacitor cells drops to 1.45V (at which point the voltage of the series capacitors is 1.45*3 = 4.35V),

[0049] Connect the capacitor in series to the lower-voltage battery cell, Cell B (3.6V). Cell B will begin to discharge until its voltage drops to 1.45V (at which point the series capacitor voltage is 4.35V). Repeat the charging and discharging steps until Cell A and Cell B are balanced to approximately 3.7V, at which point the three cells are balanced.

[0050] In practical applications, during the discharge and charging of individual battery cells, it is also necessary to monitor the voltage of the selected battery cells, including the battery to be discharged and the battery to be charged, as well as the supercapacitor, to ensure that the voltage of the battery and capacitor connected to both sides of the bidirectional synchronous BUCK circuit is within the normal range during the charging and discharging process.

[0051] In some optional embodiments, after the battery selection module selects the battery to be discharged, the method further includes: if the voltage of the battery to be discharged is within the normal range and the polarity is normal, diagnosing whether the capacitor voltage of the supercapacitor in parallel mode is normal, and controlling the bidirectional synchronous BUCK to form a working state in which the supercapacitor discharges to the battery to be charged; if the capacitor voltage is abnormal, reporting a fault; if the battery polarity of the battery to be discharged is abnormal, reporting a fault; if the voltage of the battery to be discharged is abnormal, reporting a fault.

[0052] This embodiment diagnoses the voltage and polarity of the discharging battery, as well as the capacitor voltage, to determine whether the requirements for the bidirectional synchronous BUCK circuit to control the battery to discharge to the capacitor are met, thus ensuring that the battery discharge is in progress.

[0053] In some optional embodiments, after the battery selection module selects the battery to be recharged, the method further includes: if the voltage of the battery to be recharged is within the normal range and the polarity is normal, diagnosing whether the voltage of the capacitor in the series mode is normal; if the capacitor voltage is normal, controlling the bidirectional synchronous BUCK to form a supercapacitor discharging to the battery to be recharged; if the capacitor voltage is abnormal, reporting a fault; if the battery polarity of the battery to be recharged is abnormal, reporting a fault; if the voltage of the battery to be recharged is not within the normal range, reporting a fault.

[0054] This embodiment diagnoses the voltage and polarity of the discharging battery, as well as the capacitor voltage, to determine whether the requirements for the bidirectional synchronous BUCK circuit to control the capacitor to discharge to the battery that needs to be charged are met, so as to ensure that the battery charging is in progress.

[0055] In a second embodiment of this application, a battery balancing method is provided, comprising the steps of:

[0056] S201, Initialization;

[0057] S202, waiting;

[0058] S203, determine whether an equalization command has been received;

[0059] S204, if not, return to step S202;

[0060] S205, if so, select the option to discharge the battery;

[0061] S206, Diagnose whether the battery voltage is within the normal range;

[0062] S207, if not, report the fault and proceed to step S228;

[0063] S208, diagnose whether the battery polarity is normal;

[0064] S209, if not, report the fault and execute step S228;

[0065] S210, if so, controls the supercapacitors to be connected in parallel;

[0066] S211, to diagnose whether the capacitor voltage is normal;

[0067] S212, if not, report the fault and execute step S228;

[0068] S213, if so, control the bidirectional synchronous BUCK circuit to enable the battery to discharge to the capacitor by controlling the MOSFET on the battery side.

[0069] S214, diagnoses whether the capacitor voltage has reached the charging threshold.

[0070] S215, if not, return to step S213;

[0071] S216, if so, control the bidirectional synchronous BUCK circuit to stop working;

[0072] S217, controls the battery selection module to select rechargeable batteries;

[0073] S218, diagnoses whether the battery voltage is within the normal range;

[0074] S219. If not, report the fault and proceed to step S228.

[0075] If it is S220, check if the battery polarity is normal.

[0076] S221, if not normal, report the fault and execute step S228;

[0077] S222, No normal, control the bidirectional synchronous BUCK circuit capacitor-side MOSFET to make the capacitor discharge to the selected battery.

[0078] S223, diagnoses whether the capacitor voltage has reached the discharge threshold;

[0079] S224, if not, return to step S222;

[0080] S225, if so, controls the BUCK circuit to stop working;

[0081] S226, Check if a stop balancing command has been received;

[0082] S227, If not, return to step S205;

[0083] S228, if so, end method.

[0084] The active battery balancing method provided in this embodiment uses a bidirectional synchronous BUCK circuit as the energy conversion circuit for battery balancing. Taking advantage of the bidirectional synchronous BUCK circuit's ability to switch voltage in two directions, it transfers battery power to a supercapacitor for a selected discharging battery, and then transfers the power stored in the supercapacitor to a selected recharging battery, thereby achieving battery power balancing. Since the bidirectional synchronous BUCK circuit uses a low-loss MOSFET instead of a diode in a traditional BUCK circuit, the low loss allows for a significant increase in control complexity while effectively improving system balancing efficiency and overall energy conversion efficiency.

[0085] It should be understood that the sequence number of each step in the above embodiments does not imply the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of this disclosure.

[0086] In the third embodiment of this application, see Figures 2 to 6 A battery balancing system is provided, including a battery gating module, a supercapacitor module, a bidirectional synchronous BUCK module, and a controller. The battery gating module and the supercapacitor module are respectively connected to opposite sides of the bidirectional synchronous BUCK module. The battery gating module is used to connect to the battery pack, and the controller is connected to the battery gating module, the supercapacitor module, and the bidirectional synchronous BUCK module. Among these, [the system is described in the context of...]. Figure 6 As shown, the controller includes at least a processor 601, a memory 602, and a computer program 603 stored in the memory 602 and executable on the processor 601. When the processor 601 executes the computer program 603, it implements the steps in the various method embodiments described above. Alternatively, when the processor 601 executes the computer program 603, it implements the functions of each module / unit in the various device embodiments described above.

[0087] Specifically, in combination Figure 3The bidirectional synchronous BUCK includes at least four MOSFETs and one inductor L. The four MOSFETs are designated Q1, Q2, Q3, and Q4, and are divided into two groups, each containing two MOSFETs (upper and lower). Specifically, Q1 and Q2 are located on one side of the circuit, forming one group, for connecting the battery pack. A battery selection module is also connected between the battery pack and the side of the circuit containing Q1 and Q2. Q3 and Q4 are located on the other side of the circuit, forming another group, for connecting the supercapacitor. One end of the inductor L is connected to the common node connecting Q1 and Q2, and the other end of the inductor L is connected to the common node connecting Q3 and Q4. Charging the supercapacitor from individual battery cells in the battery pack is achieved by controlling switches Q1 and Q2; discharging the battery cells from the battery pack from the supercapacitor is achieved by controlling switches Q3 and Q4. It should be noted that the operating states of Q1, Q2, Q3, and Q4 are controlled by a drive circuit. The structure of the drive circuit is conventional technology and is not a contribution to the prior art, therefore it will not be described in detail here.

[0088] Preferably, a current-limiting circuit is also connected to the circuit of Q2 and the battery selection module. By adding a current-limiting circuit to the bidirectional synchronous BUCK circuit, the battery and circuit can be protected from overcurrent, ensuring the safe and stable operation of the system. The specific implementation of the current-limiting circuit is not unique, and includes, but is not limited to, resistor current-limiting circuits, diode-resistor current-limiting circuits, transistor current-limiting circuits, operational amplifier current-limiting circuits, constant current diode current-limiting circuits, or integrated current-limiting devices.

[0089] Specifically, see Figure 4 The battery selection module includes a switching matrix composed of multiple MOSFETs for selectively connecting different battery packs and individual battery cells within those packs, as well as a control circuit for controlling the operation of each MOSFET. It also includes a diagnostic circuit for detecting the battery voltage and / or polarity of the selected battery cells to determine if the selected battery is functioning correctly. The control circuit and diagnostic circuit are conventional technologies and can be implemented using existing technologies; this application does not limit their implementation.

[0090] In some alternative embodiments, the supercapacitor module includes multiple capacitors and a control circuit, with at least one switch between each capacitor. The control circuit is connected to each switch to control the switch so as to control the multiple capacitors to be connected in parallel or in series.

[0091] Specifically, see Figure 5The supercapacitor module comprises three capacitor units, which are connected in parallel or series via a control circuit. The control circuit can consist of multiple switches, with at least one switch between each capacitor. When charging the supercapacitor, the control circuit controls the corresponding switches to connect the capacitor units in parallel; when discharging the supercapacitor, the control circuit controls the corresponding switches to connect the capacitor units in series. For example, when charging the supercapacitor, the capacitor units are connected in parallel, and when the voltage of a capacitor unit rises to a first voltage threshold, the controller is notified to stop the bidirectional synchronous BUCK circuit. When discharging the supercapacitor, the capacitor units are connected in series, and when the voltage of a capacitor unit drops to a second voltage threshold, the controller is notified to stop the bidirectional synchronous BUCK circuit.

[0092] Preferably, the supercapacitor module further includes a diagnostic circuit for detecting whether the voltage of the capacitor cells meets a preset voltage threshold. The diagnostic circuit can diagnose the voltage of each capacitor cell in both parallel and series configurations to determine whether the capacitor voltage has reached a preset first or second voltage threshold.

[0093] The controller may include, but is not limited to, processor 601 and memory 602. Those skilled in the art will understand that... Figure 6 This is merely an example of a controller and does not constitute a limitation on the controller. It may include more or fewer components than shown, or different components.

[0094] The processor 601 may be a central processing unit (CPU), or other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc.

[0095] The memory 602 can be an internal storage unit of the controller, such as the controller's hard drive or RAM. The memory 602 can also be an external storage device of the controller, such as a plug-in hard drive, SmartMedia Card (SMC), Secure Digital (SD) card, Flash Card, etc., all equipped on the controller. The memory 602 can also include both internal and external storage units of the controller. The memory 602 is used to store computer programs and other programs and data required by electronic devices.

[0096] Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the above-described division of functional units and modules is merely an example. In practical applications, the above functions can be assigned to different functional units and modules as needed, that is, the internal structure of the device can be divided into different functional units or modules to complete all or part of the functions described above. The functional units and modules in the embodiments can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or as a software functional unit.

[0097] If an integrated module / unit is implemented as a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, all or part of the processes in the methods of the above embodiments can also be implemented by a computer program instructing related hardware. The computer program can be stored in a computer-readable storage medium, and when executed by a processor, it can implement the steps of the various method embodiments described above. The computer program may include computer program code, which can be in the form of source code, object code, executable files, or certain intermediate forms. A computer-readable medium may include: any entity or device capable of carrying computer program code, recording media, USB flash drives, portable hard drives, magnetic disks, optical disks, computer memory, read-only memory (ROM), random access memory (RAM), electrical carrier signals, telecommunication signals, and software distribution media, etc. It should be noted that the content included in a computer-readable medium may be appropriately added to or subtracted according to the requirements of legislation and patent practice in a jurisdiction. For example, in some jurisdictions, according to legislation and patent practice, computer-readable media may not include electrical carrier signals and telecommunication signals.

[0098] In the fourth embodiment of this application, see Figure 7 A vehicle is provided, including a power battery comprising multiple battery packs, each battery pack consisting of multiple individual battery cells. The vehicle also includes the aforementioned battery balancing system, and the active battery balancing system is connected to at least one battery pack of the power battery. Preferably, the vehicle in this embodiment is a new energy vehicle equipped with a battery pack.

[0099] Specifically, in combination Figures 2 to 5In this context, the main control unit can be the main controller in the vehicle's battery management system. Each battery pack can correspond to a battery balancing system, and each battery balancing system connects to the main control unit via a communication module, preferably a CAN communication module. Furthermore, the controllers in the battery balancing systems can be microcomputers (MCUs) or similar devices. When battery balancing is required, the main control unit sends balancing commands to the controllers in each battery balancing system, and the controllers execute the balancing commands accordingly. Figure 1 The steps of the method shown.

[0100] This embodiment applies an active battery balancing system to automobiles to balance battery charge. This not only extends battery life and improves overall vehicle performance, but also enhances system safety and economy, ultimately improving the overall user experience of the vehicle.

[0101] The above embodiments are only used to illustrate the technical solutions of this disclosure, and are not intended to limit it. Although this disclosure has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this disclosure, and should all be included within the protection scope of this disclosure.

Claims

1. A battery equalization method characterized by, The battery equalization method is applied to a circuit in which a battery pack and a super capacitor are respectively connected on two sides of a bidirectional synchronous BUCK, and the battery equalization method comprises the following steps: Upon receiving an equalization instruction, repeatedly performing the following steps until a stop equalization instruction is received: controlling the selected battery to be discharged in the battery pack to charge the super capacitor through the bidirectional synchronous BUCK; monitoring the state of the super capacitor during the charging process; if the super capacitor reaches a target charging state, controlling the super capacitor to charge the selected battery to be charged in the battery pack through the bidirectional synchronous BUCK; monitoring the state of the super capacitor during the discharging process; if the super capacitor reaches a target discharging state, controlling the bidirectional synchronous BUCK to stop working; The bidirectional synchronous BUCK at least comprises four first MOSFETs and one inductor L, the four first MOSFETs are divided into two groups, each group comprising an upper first MOSFET and a lower first MOSFET, wherein the first group is used for connecting the battery pack, and a battery selection module is further connected between the battery pack and the side of the circuit where the first group is located; the second group is used for connecting the super capacitor; the two ends of the inductor L are respectively connected to the common node of the first group and the common node of the second group; the battery selection module comprises a switch matrix composed of a plurality of second MOSFETs, which is used for selectively connecting different battery packs and each battery monomer in the battery pack, and a control circuit for controlling the operation of each second MOSFET; The control of the selected battery to be discharged in the battery pack to charge the super capacitor through the bidirectional synchronous BUCK comprises: controlling the selection module to select the battery to be discharged; controlling the super capacitor to switch to a parallel mode, and controlling the bidirectional synchronous BUCK to form a working state in which the battery to be discharged discharges to the super capacitor; The control of the super capacitor to charge the selected battery to be charged in the battery pack through the bidirectional synchronous BUCK comprises: controlling the selection module to select the battery to be charged; controlling the super capacitor to switch to a series mode, and controlling the bidirectional synchronous BUCK to form a working state in which the super capacitor discharges to the battery to be charged.

2. The method of claim 1, wherein, The monitoring of the state of the super capacitor during the charging process comprises: monitoring whether the voltage of the super capacitor rises to a preset first voltage threshold; if the voltage of the super capacitor rises to the first voltage threshold, controlling the bidirectional synchronous BUCK to stop working; if the voltage of the super capacitor does not rise to the first voltage threshold, continuously monitoring whether the voltage of the super capacitor rises to the preset first voltage threshold.

3. The method of claim 1, wherein, The monitoring of the state of the super capacitor during the discharging process comprises: monitoring whether the voltage of the super capacitor falls to a preset second voltage threshold; if the voltage of the super capacitor falls to the second voltage threshold, controlling the bidirectional synchronous BUCK to stop working; if the voltage of the super capacitor does not fall to the second voltage threshold, continuously monitoring whether the voltage of the super capacitor falls to the preset second voltage threshold.

4. The method of claim 1, wherein, After the selection module is controlled to select the battery to be discharged, the method further comprises: controlling the selection module to select the battery to be discharged; diagnose whether the capacitor voltage of the parallel mode is normal when the voltage of the battery to be discharged is in the normal range and the polarity is normal; if the capacitor voltage is normal, control the bidirectional synchronous BUCK to form the working state of discharging the super capacitor to the battery to be charged; if the capacitor voltage is not normal, report a fault; if the battery polarity of the battery to be discharged is not normal, report a fault; if the voltage of the battery to be discharged is not normal, report a fault.

5. The method of claim 1, wherein, After the control gating module gates the battery to be charged, further comprising: diagnose whether the capacitor voltage of the series mode is normal when the voltage of the battery to be charged is in the normal range and the polarity is normal; if the capacitor voltage is normal, control the bidirectional synchronous BUCK to form the working state of discharging the super capacitor to the battery to be charged; if the capacitor voltage is not normal, report a fault; if the battery polarity of the battery to be charged is not normal, report a fault; if the voltage of the battery to be charged is not in the normal range, report a fault.

6. A battery equalization system characterized by, comprising: a battery gating module, a super capacitor module, a bidirectional synchronous BUCK module and a controller, the battery gating module and the super capacitor module are connected on both sides of the bidirectional synchronous BUCK module, the battery gating module is used to connect with a battery pack, the controller is connected with the battery gating module, the super capacitor module and the bidirectional synchronous BUCK module, and the controller at least comprises a memory, a processor and a computer program stored in the memory and executable on the processor, and the processor implements the steps of the method according to any one of claims 1 to 5 when executing the computer program.

7. The system of claim 6, wherein, The super capacitor module comprises a plurality of capacitors and a control circuit, at least one switch is arranged between each capacitor, the control circuit is connected with each switch and is used to control the switch to control the plurality of capacitors in parallel or in series.

8. An automobile comprising a power battery, the power battery comprising a plurality of battery packs, each battery pack being composed of a plurality of battery cells, characterized by, The automobile further comprises the battery equalization system according to claim 6 or 7, and the battery equalization system is connected with at least one battery pack of the power battery.

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