Battery pack active equalization system and method, medium and vehicle

Abstract

The embodiment of the invention provides a battery pack active equalization system and method, a medium and a vehicle, and relates to the technical field of battery equalization. The system comprises a battery pack which is composed of a plurality of single batteries connected in series; the first equalization module is configured to perform charging equalization on each single battery by dynamically adjusting the circuit topology of the battery pack in a charging stage; the second equalization module is configured to perform re-equalization operation on each single battery after the charging of the battery pack is cut off; and the controller is configured to control the first equalization module to execute equalization operation in a charging stage and control the second equalization module to execute re-equalization operation after charging is stopped. According to the embodiment of the invention, by arranging the first equalization module and the second equalization module, rapid topological equalization can be carried out during charging, and polarization voltage drop is actively eliminated after charging is finished, so that the equalization effect durability of the battery pack is improved, and the overall consistency and available capacity of the battery pack are further remarkably improved.

Description

Technical Field

[0001] This application relates to the field of battery balancing technology, and more specifically, to a battery pack active balancing system, method, medium, and vehicle. Background Technology

[0002] In practical applications of battery packs, differences in manufacturing processes and aging levels can lead to variations in the voltage and capacity of individual cells within the pack. Without proper equalization during charging and discharging, some cells may become overcharged or over-discharged, thus shortening the overall lifespan of the battery pack.

[0003] Currently, common active balancing solutions can achieve dynamic balancing during the charging phase, improving charging efficiency. However, these systems often overlook voltage inconsistencies caused by various factors after charging, leading to a decrease in the actual usable capacity of the battery pack and an unsustainable balancing effect, which in turn affects the overall performance and lifespan of the battery pack. Summary of the Invention

[0004] The purpose of this application is to provide a battery pack active balancing system, method, medium, and vehicle to improve the durability of the battery pack's charging balancing effect.

[0005] In a first aspect, embodiments of this application provide a battery pack active balancing method, including: A battery pack consists of multiple individual cells connected in series. The first equalization module is connected to the battery pack and is configured to perform charging equalization on each individual battery cell by dynamically adjusting the circuit topology of the battery pack during the charging phase of the battery pack. The second equalization module, connected to the battery pack, is configured to perform energy transfer between adjacent individual cells in response to voltage differences caused by polarization effects after the charging of the battery pack is cut off, so as to perform a rebalancing operation on each of the individual cells. The controller is connected to the first equalization module and the second equalization module respectively, and is configured to control the first equalization module to perform equalization operation during the charging phase, and to control the second equalization module to perform re-equalization operation after the charging is cut off.

[0006] In this embodiment, by setting a first equalization module and a second equalization module, and having them coordinated by the same controller in stages, rapid topology equalization can be performed during charging, and polarization voltage drop can be actively eliminated after charging is completed, thereby improving the durability of the equalization effect of the battery pack and significantly improving the overall consistency and usable capacity of the battery pack.

[0007] In some embodiments, the first equalization module includes a reconfigurable switching circuit connected in parallel with each of the individual cells, the reconfigurable switching circuit being configured to connect the corresponding individual cell to the charging circuit or bypass it from the charging circuit in response to an instruction from the controller.

[0008] In the embodiments of this application, by setting a controlled reconfigurable switching circuit in parallel for each battery, a single battery can be precisely connected to or bypassed in the charging circuit according to instructions, thereby achieving differentiated and selective charging of batteries with different capacities, improving the targeted nature of the charging balance and the efficiency of energy utilization.

[0009] In some embodiments, the reconfigurable switching circuit includes a first switch and a second switch connected in parallel with each individual battery cell; wherein, when the first switch is closed and the second switch is open, the corresponding individual battery cell is connected to the charging circuit; and when the first switch is open and the second switch is closed, the corresponding individual battery cell is bypassed from the charging circuit.

[0010] In the embodiments of this application, by adopting a simple parallel circuit structure consisting of two switches, reliable state switching can be achieved with low hardware cost, thereby simplifying circuit design and enhancing the feasibility and stability of the system.

[0011] In some embodiments, the controller is configured to execute a voltage balancing strategy based on a consensus algorithm during the charging phase; The voltage equalization strategy includes: A single cell is identified as a reference node, the voltage error between the remaining single cells and the reference node is calculated, and the state of each of the reconfigurable switching circuits is controlled based on the voltage error.

[0012] In the embodiments of this application, by adopting a control strategy based on a consensus algorithm during the charging phase, all battery voltages can intelligently and collaboratively converge to the reference value, thereby achieving fast and accurate voltage balancing during the charging process and reducing the risk of overcharging or undercharging.

[0013] In some embodiments, the second equalization module includes a plurality of buck-boost converter circuit units, each buck-boost converter circuit unit being disposed between two adjacent individual cells, and each buck-boost converter circuit unit being used to realize bidirectional energy transfer between the corresponding two individual cells.

[0014] In this embodiment of the application, by setting an independent buck-boost converter circuit unit between each adjacent battery, efficient bidirectional energy transfer can be carried out directly between high and low voltage batteries when a voltage difference is detected, thereby quickly compensating for voltage inconsistency caused by polarization effect and realizing fine local energy redistribution.

[0015] In some embodiments, the controller is configured to: After charging is stopped, the battery pack is left to stand still for a preset time, and then the voltage of each individual battery cell is collected. The voltage difference is calculated based on the voltage of each individual cell, and when the voltage difference exceeds a preset threshold, it is determined that there is a voltage difference caused by polarization effect, and the second equalization module is controlled to perform a re-equalization operation.

[0016] In this embodiment, by employing a trigger logic that monitors and judges after a period of inactivity, the actual voltage difference and transient polarization voltage after charging are accurately distinguished, thereby initiating rebalancing only when necessary, avoiding unnecessary energy loss, and improving the overall energy efficiency and intelligent control level of the system.

[0017] In some embodiments, the controller is configured to: When controlling the second equalization module to perform the re-equalization operation, the switching transistors in each buck-boost converter circuit unit are controlled to operate with a preset duty cycle, so that they operate in continuous conduction mode.

[0018] In the embodiments of this application, by controlling the switching transistor to operate at a specific duty cycle and ensuring that the circuit operates in a continuous conduction mode, the inductor energy storage and release process can be optimized, current ripple and switching losses can be reduced, thereby significantly improving energy transfer efficiency and reducing adverse effects on electromagnetic compatibility.

[0019] In some embodiments, during the charging phase, the battery pack is charged using a constant current charging method.

[0020] In this embodiment of the application, by adopting a constant current charging method during the charging stage and combining it with the active balancing capability of the system, the battery pack voltage can be rapidly increased with a higher current, thereby significantly shortening the charging time while ensuring safety and meeting the application scenario requirements of fast charging.

[0021] In some embodiments, the controller is configured to: After the second equalization module performs the re-equalization operation, the voltage of each individual cell is collected again, and it is determined whether the equalization target has been achieved. If the equilibrium target is not achieved, the second equilibrium module is controlled to perform a re-equilibrium operation again until the equilibrium target is achieved. The equalization target includes a voltage difference below a preset threshold or the number of re-equalization operations reaching a preset threshold.

[0022] In this embodiment, by introducing closed-loop control logic of iterative judgment and cyclic execution after rebalancing, it can be ensured that the voltage difference is continuously corrected until it is lower than the target threshold, thereby achieving a stable and reliable final equalization effect and eliminating the inconsistency problem that may remain after a single equalization.

[0023] Secondly, embodiments of this application provide a battery pack active balancing method, applied to any of the battery pack active balancing systems described in the claims, comprising: During the charging phase of the battery pack, the circuit topology of the battery pack is dynamically adjusted to perform charging equalization operations on individual cells. After the battery pack is charged, monitor the voltage of each individual cell to determine if there are voltage differences due to polarization effects. If the voltage difference is determined to exist, a rebalancing operation is performed on each individual cell by transferring energy between adjacent individual cells.

[0024] Thirdly, embodiments of this application provide a computer-readable storage medium storing a computer program, which, when executed by a processor, can implement the methods described in the method embodiments.

[0025] Fourthly, embodiments of this application provide a vehicle including any of the described battery pack active balancing systems. Attached Figure Description

[0026] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments of this application will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0027] Figure 1 This is a schematic diagram of the structure of an active balancing system for a battery pack provided in an embodiment of this application; Figure 2 A schematic diagram of a reconfigurable equalization circuit provided in an embodiment of this application; Figure 3 This is a battery pack communication topology diagram provided in an embodiment of this application; Figure 4 This is a schematic diagram of a buck-boost converter circuit unit provided in an embodiment of this application; Figure 5 A waveform diagram of the inductor current provided in an embodiment of this application; Figure 6 A schematic flowchart of an active battery pack balancing method provided in an embodiment of this application; Figure 7 This is a schematic diagram of the structure of an active battery balancing device provided in an embodiment of this application; Figure 8 This is a schematic diagram of the structure of an electronic device provided in an embodiment of this application. Detailed Implementation

[0028] The technical solutions in the embodiments of this application will now be described with reference to the accompanying drawings.

[0029] It should be noted that similar reference numerals and letters in the following figures indicate similar items; therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures. Furthermore, in the description of this application, terms such as "first," "second," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0030] It should be noted that if equalization is not performed during the charging and discharging process of the battery pack, some batteries may be overcharged or over-discharged, thereby shortening the battery pack's lifespan.

[0031] Currently, existing lithium battery pack balancing circuits are divided into two categories: passive balancing and active balancing. Passive balancing achieves balancing by consuming excess energy through parallel shunt resistors, but this method has the problem of energy waste. Although active balancing can transfer energy from high-energy batteries to low-energy batteries, this type of balancing circuit usually has a relatively fixed topology, and the failure of a single battery can easily lead to the failure of the entire battery pack.

[0032] Furthermore, while traditional active balancing circuits can achieve good balancing during charging, they overlook the voltage inconsistency caused by factors such as voltage drop after charging. Traditional constant current / constant voltage charging methods, although mitigating voltage drop, have excessively long charging times, making them unsuitable for fast charging scenarios. Therefore, a battery charging balancing solution that effectively addresses the voltage drop problem, offers fast charging speeds, and provides excellent balancing performance is needed.

[0033] To address the problems existing in the prior art, this application provides an active battery balancing system that can effectively solve the problem of voltage inconsistency caused by voltage drop after battery charging, and improve charging speed and the durability of balancing effect.

[0034] like Figure 1 As shown in the figure, this application provides a battery pack active balancing system, including: A battery pack consists of multiple individual cells connected in series. The first equalization module, connected to the battery pack, is configured to perform charging equalization of each individual battery cell by dynamically adjusting the circuit topology of the battery pack during the charging phase of the battery pack. The second equalization module, connected to the battery pack, is configured to perform energy transfer between adjacent individual cells in response to voltage differences caused by polarization after the battery pack is de-charged, so as to perform rebalancing operation on each individual cell. The controller is connected to the first equalization module and the second equalization module respectively, and is configured to control the first equalization module to perform equalization operation during the charging phase, and to control the second equalization module to perform re-equalization operation after the charging is cut off.

[0035] like Figure 1 As shown, the active battery balancing system provided in this embodiment mainly includes a battery pack, a first balancing module, a second balancing module, and a controller.

[0036] For example, the battery pack consists of multiple (e.g., n, n≥2) rechargeable individual cells (such as lithium-ion batteries) B1, B2, ... B n Composed in series. For example... Figure 1 or Figure 2 As shown ( Figure 2 To omit the reconfigurable balancing circuit of the second balancing module, the first balancing module is electrically connected to the battery pack. Its core function is to dynamically adjust the circuit connection topology of the battery pack during the charging phase (i.e., while the external charger is charging it). Specifically, it can selectively control which individual cells (one or more) are connected to the main charging circuit to receive charging, and it can also selectively control one or more individual cells to bypass the main charging circuit, thereby achieving real-time balancing during the charging process.

[0037] It should be noted that polarization is a phenomenon where, during the charging and discharging process of a battery, the terminal voltage deviates from the equilibrium voltage due to limitations in the internal electrochemical reaction rate and charge migration rate. For series-connected battery packs, the polarization characteristics (degree of polarization and rate of degradation) of each individual cell are not entirely identical due to subtle differences in materials, manufacturing processes, aging, and temperature. Therefore, after charging is stopped and the battery is left to rest, the voltage drop (polarization voltage drop) of each cell will differ, leading to voltage inconsistencies in the battery pack under static conditions.

[0038] The second equalization module is also connected to the battery pack. Its difference from the first equalization module is that it is configured to activate only after the battery pack's charging process has completely stopped (e.g., reaching a preset charging cutoff voltage). The main function of the second equalization module is to respond to voltage inconsistencies between individual cells within the battery pack caused by polarization effects. By transferring energy between adjacent cells within the module, it performs one or more rebalancing operations on all individual cells to compensate for voltage differences that occur after resting.

[0039] The controller can, for example, employ a microcontroller unit (MCU) or a battery management system (BMS) main chip, and is communicatively connected to both the first and second equalization modules. The controller is configured to execute two-stage control logic: during the charging phase, it outputs a control signal to drive the first equalization module to perform an equalization operation; after charging is stopped, it outputs a control signal to drive the second equalization module to perform a re-equalization operation.

[0040] This application embodiment sets up a first equalization module and a second equalization module, which are controlled in stages by the same controller. This enables rapid topology equalization during charging and actively eliminates polarization voltage drop after charging is completed, thereby improving the durability of the battery pack's equalization effect and significantly enhancing the overall consistency and usable capacity of the battery pack.

[0041] In some embodiments, the first equalization module includes a reconfigurable switching circuit connected in parallel with each individual cell, the reconfigurable switching circuit being configured to connect the corresponding individual cell to the charging circuit or bypass it from the charging circuit in response to a controller instruction.

[0042] In some embodiments, the reconfigurable switching circuit includes a first switch and a second switch connected in parallel with each individual battery cell; wherein, when the first switch is closed and the second switch is open, the corresponding individual battery cell is connected to the charging circuit; and when the first switch is open and the second switch is closed, the corresponding individual battery cell is bypassed from the charging circuit.

[0043] like Figure 1 As shown, the first equalization module specifically includes a reconfigurable switching circuit connected in parallel with each individual battery cell.

[0044] For example, the circuit includes two types of switching devices, wherein the circuit portion corresponding to the i-th single cell includes a first switch S. a,i Second switch S b,i The controller can independently control the opening and closing of each switch via a drive circuit (not shown in the diagram). Its operating modes are as follows: Charging access mode: When the controller determines that a certain single battery B i When charging is needed, control S a,i Close, and S b,i Disconnect. At this time, the corresponding single cell B... i When connected to the charging circuit, the charging current will flow through the individual battery B. i To charge it.

[0045] Bypass mode: When the controller determines that a single cell B... i When the voltage is high enough or charging needs to be paused, control S a,i Disconnect, and S b,i Close. At this time, the corresponding single cell B iSince the charging circuit is bypassed, the charging current will flow through the closed S circuit. b,i This bypasses the single cell B. i Battery B i When bypassed from the main charging circuit, the voltage across its terminals remains essentially unchanged, while the current continues to charge subsequent batteries.

[0046] Based on this, by setting a controlled reconfigurable switching circuit in parallel for each battery, it is possible to precisely connect or bypass a single battery to the charging circuit according to instructions, thereby achieving differentiated and selective charging of batteries with different capacities, improving the targeted nature of the charging process and the efficiency of energy utilization.

[0047] Furthermore, by employing a simple parallel circuit structure consisting of two switches, reliable state switching can be achieved at a lower hardware cost, thereby simplifying circuit design and enhancing the feasibility and stability of the system.

[0048] In some embodiments, the controller is configured to execute a voltage balancing strategy based on a consensus algorithm during the charging phase; Voltage balancing strategies include: The single cell is determined as the reference node, the voltage error between the remaining single cells and the reference node is calculated, and the state of each reconfigurable switching circuit is controlled based on the voltage error.

[0049] For example, in this embodiment of the application, the consensus algorithm refers to a distributed cooperative control algorithm applied to a battery pack composed of multiple series-connected individual cells. This algorithm abstracts each individual cell as a communication-capable intelligent agent (node) and connects them through a preset communication topology. The goal of this algorithm is to converge the terminal voltages of all individual cells to a consistent level.

[0050] For example, during the charging phase, the controller is configured to execute a voltage balancing strategy based on consistency theory, the software implementation of which may include: First, the voltage of all individual cells is collected in real time, and specific individual cells are set as reference nodes based on the voltage. For example, the cell with the highest current voltage is selected as the reference node. The advantage of this setting is that, with a relatively high voltage as the benchmark, the difference between the voltage of other cells and the benchmark can be effectively judged, which facilitates subsequent control of the switching state based on the voltage error, and realizes balanced control of the battery charging process.

[0051] Then, for any single cell other than the reference node i Calculate the corresponding voltage error For example, voltage error The calculation formula is as follows:

[0052] in, The battery voltage at the reference node; It is a single cell battery i The voltage; It is a constraint gain; These are the elements of the adjacency matrix, representing the battery. i With battery j In the preset communication topology (such as Figure 3 The connection relationships shown in the figure; Indicates with battery i Neighbor Battery j The voltage; Indicates battery i The neighbor set.

[0053] It should be noted that the adjacency matrix is ​​a graph-based matrix used to describe the communication topology of a battery pack. In the battery pack communication topology of this scheme, if the battery... i With battery j If there is a direct communication connection between them (which can be understood as an association between them in the circuit topology), then the adjacency matrix elements... = 1; if no direct connection exists, then = 0. Constructing an adjacency matrix in this way clearly reflects the connection relationships between the batteries within the battery pack, providing basic data for calculating battery voltage errors, and thus enabling accurate control of the battery charging state.

[0054] The battery calculated by the above formula i The error depends not only on the difference from the reference voltage but also on the voltage of its "neighboring" batteries. By calculating the error between each battery voltage and the reference voltage, it is determined whether the battery voltage is higher or lower than the reference value. Based on the error, the switching state of the corresponding battery circuit is controlled to determine whether the battery continues to charge or bypasses and stops charging, thus achieving equalization during the battery pack charging process.

[0055] Then, based on the calculated Value generation control instructions. For example, setting a zero value or a small positive threshold, if... ≤0 (indicating battery) i If the voltage is close to or higher than the equilibrium target, then the corresponding reconfigurable switching circuit is controlled to enter bypass mode; if >0 (indicates battery) i If the voltage is too low, the controller will connect the battery to the charging circuit. The controller periodically executes the above steps to dynamically converge all battery voltages to the reference value, achieving equalization during the charging phase. At the same time, by dynamically switching the topology of the battery connected to the charging circuit, only low-voltage batteries are charged, reducing the time when multiple batteries are charged simultaneously and reducing the risk of overheating.

[0056] Based on this, by adopting a control strategy based on a consensus algorithm during the charging phase, all battery voltages can intelligently and collaboratively converge to the reference value, thereby achieving fast and accurate voltage balancing during the charging process and reducing the risk of overcharging or undercharging.

[0057] In some embodiments, the second equalization module includes a plurality of buck-boost converter circuit units, each buck-boost converter circuit unit being disposed between two adjacent single cells, and each buck-boost converter circuit unit being used to realize bidirectional energy transfer between the corresponding two single cells.

[0058] like Figure 1 As shown, the second equalization module includes multiple (n-1) buck-boost converter circuit units (Buck-Boost circuits).

[0059] Each conversion circuit unit is connected across two adjacent individual cells. B i and B i+1 ( i The range is between 1, 2, ..., n-1. Each unit typically contains an inductor. L i Two high-frequency switching transistors (such as MOSFETs) S k,i and S k,i+1 And the corresponding driving and sampling circuits.

[0060] Through the controller S k,i and S k,i+1 By employing pulse width modulation (PWM) control, this circuit can transfer energy from a neighboring battery with a higher voltage to a neighboring battery with a lower voltage, enabling bidirectional energy flow. For example, when energy needs to be transferred from... B i Transferred to B i+1 At that time, by controlling S k,i and S k,i+1 The switch, the inductor L i First by B i Charging and energy storage, then to B i+1 Discharge energy.

[0061] like Figure 1As shown, it can be understood that for a reconfigurable circuit composed of n batteries, the number of Buck-Boost circuits increases by n - 1. This is because a Buck-Boost circuit is needed between every two adjacent batteries to achieve energy transfer between them, compensating for the voltage drop difference after resting.

[0062] The Buck-Boost circuit is positioned between two adjacent batteries. Specifically, in the improved reconfigurable circuit, the Buck-Boost circuit corresponding to L1 is connected between batteries B1 and B2, the Buck-Boost circuit corresponding to L2 is connected between batteries B2 and B3, and so on. Through this connection method, the Buck-Boost circuit can transfer energy from the high-voltage battery to the low-voltage battery when the voltage difference exceeds a threshold, solving the polarization effect problem that traditional reconfigurable circuits cannot handle.

[0063] Based on this, by setting an independent buck-boost converter circuit unit between each adjacent battery, efficient bidirectional energy transfer can be carried out directly between high and low voltage batteries when a voltage difference is detected, thereby quickly compensating for voltage inconsistency caused by polarization effect and realizing refined local energy redistribution.

[0064] In some embodiments, the controller is configured to: After charging is stopped, the battery pack is left to stand for a preset time, and then the voltage of each individual battery cell is collected. The voltage difference is calculated based on the voltage of each individual cell, and when the voltage difference exceeds a preset threshold, it is determined that there is a voltage difference caused by polarization effect, and the second equalization module is controlled to perform a re-equalization operation.

[0065] In some embodiments, the controller is configured to: When controlling the second equalization module to perform the re-equalization operation, the switching transistors in each buck-boost converter circuit unit are controlled to operate with a preset duty cycle, so that they operate in continuous conduction mode.

[0066] It should be noted that after charging is stopped, the controller is configured to execute the following process: First, the battery pack is put into a resting state, all charging or discharging operations are stopped, and a timer begins. The resting period is preset (e.g., 2-5 minutes) to allow the polarization voltage of each battery to decay sufficiently. After the resting period, the controller collects the terminal voltage of each individual battery cell through a voltage sampling circuit.

[0067] It should be noted that the "preset duration" refers to a time sufficient for the polarization voltage of each battery to decay sufficiently. This "preset duration" must be set to allow the overpotential generated by charging polarization in each individual battery to decay sufficiently, thereby revealing the inconsistency in the actual terminal voltage caused by differences in internal states. For example, the specific value of the "preset duration" can be set based on the battery's chemical system and characteristics; for common lithium-ion batteries, this preset duration is typically set between 2 and 5 minutes.

[0068] Then, the voltage difference is calculated based on the voltage of each individual cell. For example, the voltage difference between each individual cell can be calculated separately, and the maximum value can be obtained as the maximum voltage difference; or, the difference between the maximum and minimum values ​​of all cell voltages can be calculated to obtain the maximum voltage difference.

[0069] Then, the maximum voltage difference is compared with a preset voltage difference threshold (e.g., 10mV). If the maximum voltage difference exceeds the threshold, the controller determines that there is a significant voltage difference due to asynchrony caused by polarization effects, and rebalancing needs to be initiated.

[0070] It should be noted that the "voltage difference threshold" (preset threshold) is used to distinguish between acceptable voltage fluctuations caused by measurement noise and minor self-discharge differences, and significant voltage differences caused by inconsistent polarization effects that require active compensation. The setting of this threshold should take into account the following factors: 1. To avoid false triggering, the threshold should be significantly greater than the system voltage detection accuracy; 2. It should ensure that the benefits of initiating rebalancing outweigh the losses in the energy transfer process itself, and is typically set in the range of 5mV to 20mV, for example, 10mV.

[0071] Subsequently, the controller sends control commands to the second equalization module. For adjacent battery pairs that require energy transfer, the controller calculates and sets the duty cycle of the switching transistors in the corresponding Buck-Boost circuit unit.

[0072] For example, the duty cycle is calculated as follows:

[0073] Where, represents the duty cycle, L This is the inductance value. R Represents the equivalent resistance in the circuit (e.g.) Figure 4 (R1+R2 in the middle) T Indicates the switching cycle. This indicates the voltage of a high-voltage battery (such as a battery with a higher voltage connected to an inductor in the application scenario of the formula). This indicates the voltage of a low-voltage battery (a battery with a lower voltage connected to an inductor).

[0074] Understandably, by controlling this duty cycle, the inductor current is ensured to flow continuously throughout the entire switching cycle, i.e., operating in continuous conduction mode (CCM). Based on this CCM mode, energy transfer efficiency is improved and control is simplified. The waveform diagram of the inductor current is shown below. Figure 5 As shown, where T represents the switching period and D represents the duty cycle, this waveform represents the battery charging the inductor during the DT time period, in (1 During the D)T time period, the inductor discharges into the battery.

[0075] Based on this, by adopting a trigger logic that monitors and judges after static conditions, it is possible to accurately distinguish between the actual voltage difference and transient polarization voltage after charging is completed, thereby initiating rebalancing only when necessary, avoiding unnecessary energy loss, and improving the overall energy efficiency and intelligent control level of the system.

[0076] Furthermore, by controlling the switching transistor to operate at a specific duty cycle and ensuring the circuit operates in continuous conduction mode, the inductor energy storage and release process can be optimized, current ripple and switching losses can be reduced, thereby significantly improving energy transfer efficiency and reducing adverse effects on electromagnetic compatibility.

[0077] In some embodiments, the battery pack is charged using a constant current charging method during the charging phase.

[0078] It should be noted that during the charging phase, this system controls the external charger to use a constant current charging mode for the battery pack until the total voltage of the battery pack or the voltage of any individual cell reaches its charging cutoff condition (e.g., the voltage reaches 4.2V). Compared with the traditional constant current followed by constant voltage (CC-CV) mode, this system, combined with the balancing strategy of this application, can significantly shorten the charging time.

[0079] Based on this, by adopting a constant current charging method during the charging phase and combining it with the active balancing capability of this system, the battery pack voltage can be rapidly increased with a higher current, thereby significantly shortening the charging time while ensuring safety and meeting the application requirements of fast charging.

[0080] In some embodiments, the controller is configured to: After the second equalization module performs the re-equalization operation, the voltage of each individual cell is collected again, and it is determined whether the equalization target has been achieved. If the equilibrium target is not achieved, the second equilibrium module will be controlled to perform a re-equilibrium operation again until the equilibrium target is achieved. The balancing targets include voltage differences falling below a preset threshold or the number of rebalancing operations reaching a preset threshold.

[0081] It should be noted that, to ensure a more thorough rebalancing effect, the controller can also be configured to use closed-loop iterative control logic.

[0082] Specifically, after the second equalization module completes a round of re-equalization, the controller collects the voltage of each individual cell again, recalculates the current maximum voltage difference, and then compares the maximum voltage difference with the preset equalization target threshold (which can be the same as or smaller than the aforementioned judgment threshold "voltage difference threshold").

[0083] If the maximum voltage difference is still higher than the equalization target threshold, it is determined that the equalization target has not been achieved. At this time, the controller controls the second equalization module to perform the next round of re-equalization operation.

[0084] Repeat the above closed-loop iterative control logic until the maximum voltage difference is lower than the equalization target threshold, indicating that the battery pack has recovered good consistency, and the re-equalization process ends.

[0085] Based on this, by introducing closed-loop control logic of iterative judgment and cyclic execution after rebalancing, it can be ensured that the voltage difference is continuously corrected until it is lower than the target threshold, thereby achieving a stable and reliable final equalization effect and eliminating the inconsistency problem that may remain after a single equalization.

[0086] like Figure 6 As shown, this application provides a battery pack active balancing method, applicable to any of the battery pack active balancing systems, including: S1. During the charging phase of the battery pack, the charging balance operation of individual cells is performed by dynamically adjusting the circuit topology of the battery pack. Specifically, during battery pack charging, the controller dynamically adjusts the electrical connection topology of the battery pack by controlling the reconfigurable switching circuit in the first equalization module. Based on strategies such as consensus algorithms, it is possible to selectively charge individual cells with lower voltage, achieving active equalization during the charging process.

[0087] S2. After the battery pack is charged, monitor the voltage of each individual cell to determine if there is a voltage difference due to polarization effect. Specifically, after charging is stopped, the controller first controls the battery pack to stand still. After the polarization voltage decays, the voltage of each battery is collected. By analyzing and calculating the voltage difference between batteries (such as the maximum voltage difference) and comparing it with a threshold, it is determined whether there is a voltage inconsistency problem caused by polarization effect that needs to be addressed.

[0088] S3. When a voltage difference is determined, a rebalancing operation is performed on each individual cell by transferring energy between adjacent individual cells.

[0089] Specifically, if a significant voltage difference is detected, the controller activates the second equalization module. This module performs a rebalancing operation on all individual cells by controlling each buck-boost converter unit to transfer energy between adjacent cells (e.g., operating in continuous conduction mode). For example, this operation can also be performed iteratively until the voltage difference meets the equalization target.

[0090] Compared with the prior art, the embodiments of this application have the following beneficial effects: 1. By introducing a two-stage collaborative mechanism of "equalization during charging" and "re-equalization after charging," the problem of voltage inconsistency caused by polarization effect is systematically solved. During the charging phase, real-time equalization is performed through a reconfigurable circuit; after charging is stopped and the battery is allowed to rest, a Buck-Boost circuit actively compensates for voltage deviations caused by polarization voltage drop differences. This solution ensures that the battery pack maintains extremely high voltage consistency even after a complete charging cycle, thereby significantly improving the usable capacity and energy utilization rate of the battery pack.

[0091] 2. Compared to traditional constant current and constant voltage charging methods, this embodiment of the application, by employing full-cycle constant current charging combined with a dynamic balancing strategy, achieves a measured charging speed increase of approximately 32.4%, effectively meeting the application requirements of fast charging. Simultaneously, addressing the potential for increased polarization inconsistency during fast charging, the rebalancing module in this embodiment promptly eliminates this issue, ensuring the battery pack's performance stability and safety under high-speed charging conditions, and achieving a balance between charging efficiency and system reliability.

[0092] 3. By employing a graph-based consensus equalization algorithm, the battery pack voltage can converge quickly and smoothly to a uniform level. Furthermore, reducing the time multiple batteries are charged simultaneously lowers the system's thermal load, contributing to extended battery life. In addition, the improved reconfigurable circuit topology offers high flexibility and fault tolerance. In the event of a single battery failure, the system topology can be dynamically adjusted to achieve isolation and continued operation, significantly improving the robustness and operational reliability of the entire battery management system.

[0093] Please refer to Figure 7 , Figure 7 A block diagram illustrating the composition of a battery pack active balancing device provided in some embodiments of this application is shown. It should be understood that this battery pack active balancing device is similar to the one described above. Figure 6 Corresponding to the method embodiments, it is able to perform each step involved in the above method embodiments. The specific functions of the battery pack active balancing device can be found in the description above. To avoid repetition, detailed descriptions are appropriately omitted here.

[0094] Figure 7The battery pack active balancing device includes at least one software function module that can be stored in a memory or embedded in the battery pack active balancing device in the form of software or firmware. The battery pack active balancing device includes: The equalization operation module 710 is used to perform charging equalization operation on individual cells by dynamically adjusting the circuit topology of the battery pack during the charging phase of the battery pack. The difference judgment module 720 is used to monitor the voltage of each individual cell after the battery pack is charged to determine whether there is a voltage difference caused by polarization effect. The rebalancing operation module 730 is used to perform a rebalancing operation on each individual cell by transferring energy between adjacent individual cells when a voltage difference is determined to exist.

[0095] It is understood that the above-described device embodiments correspond to the method embodiments of the present invention. The battery pack active balancing device provided by the embodiments of the present invention can realize the battery pack active balancing method provided by any one of the method embodiments of the present invention.

[0096] Those skilled in the art will understand that, for the sake of convenience and brevity, the specific working process of the device described above can be referred to the corresponding process in the aforementioned method, and will not be elaborated further here.

[0097] like Figure 8 As shown, some embodiments of this application provide an electronic device 800, which includes: a memory 810, a processor 820, and a computer program stored on the memory 810 and executable on the processor 820. When the processor 820 reads the program from the memory 810 via a bus 830 and executes the program, it can implement any of the methods included in the above-described battery pack active balancing method.

[0098] Processor 820 can process digital signals and can include various computing architectures. Examples include complex instruction set computer architectures, reduced instruction set computer architectures, or architectures that implement multiple instruction set combinations. In some examples, processor 820 can be a microprocessor.

[0099] The memory 810 can be used to store instructions executed by the processor 820 or data related to the execution of instructions. These instructions and / or data may include code for implementing some or all of the functions of one or more modules described in the embodiments of this application. The processor 820 of this disclosure embodiment can be used to execute the instructions in the memory 810 to implement the methods shown above. The memory 810 includes dynamic random access memory, static random access memory, flash memory, optical memory, or other memories well known to those skilled in the art.

[0100] Some embodiments of this application also provide a computer-readable storage medium storing a computer program that, when executed by a processor, describes the method described in the method embodiments.

[0101] Some embodiments of this application also provide a vehicle including any of the battery pack active balancing systems described above.

[0102] It should be noted that the various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. For apparatus embodiments, since they are basically similar to method embodiments, the description is relatively simple; relevant parts can be referred to the descriptions in the method embodiments.

[0103] It should be understood, in the several embodiments provided in this application, that the disclosed apparatus and methods can also be implemented in other ways. The apparatus embodiments described above are merely illustrative; for example, the flowcharts and block diagrams in the accompanying drawings illustrate the architecture, functionality, and operation of possible implementations of apparatus, methods, and computer program products according to various embodiments of this application. In this regard, each block in a flowchart or block diagram may represent a module, segment, or portion of code containing one or more executable instructions for implementing a specified logical function. It should also be noted that in some alternative implementations, the functions marked in the blocks may occur in a different order than those marked in the drawings. For example, two consecutive blocks may actually be executed substantially in parallel, and they may sometimes be executed in reverse order, depending on the functions involved. It should also be noted that each block in a block diagram and / or flowchart, and combinations of blocks in block diagrams and / or flowcharts, can be implemented using a dedicated hardware-based system that performs the specified function or action, or using a combination of dedicated hardware and computer instructions.

[0104] In addition, the functional modules in the various embodiments of this application can be integrated together to form an independent part, or each module can exist independently, or two or more modules can be integrated to form an independent part.

[0105] If the aforementioned functions are implemented as software functional modules and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, or a portion of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of this application. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0106] The above description is merely an embodiment of this application and is not intended to limit the scope of protection of this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the scope of protection of this application. It should be noted that similar reference numerals and letters in the following figures indicate similar items; therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0107] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

[0108] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

Claims

1. A battery pack active balancing system, characterized in that, include: A battery pack consists of multiple individual cells connected in series. The first equalization module is connected to the battery pack and is configured to perform charging equalization on each individual battery cell by dynamically adjusting the circuit topology of the battery pack during the charging phase of the battery pack. The second equalization module, connected to the battery pack, is configured to perform energy transfer between adjacent individual cells in response to voltage differences caused by polarization effects after the charging of the battery pack is cut off, so as to perform a rebalancing operation on each of the individual cells. The controller is connected to the first equalization module and the second equalization module respectively, and is configured to control the first equalization module to perform equalization operation during the charging phase, and to control the second equalization module to perform re-equalization operation after the charging is cut off.

2. The battery pack active balancing system according to claim 1, characterized in that, The first equalization module includes a reconfigurable switching circuit connected in parallel with each of the individual cells. The reconfigurable switching circuit is configured to, in response to a command from the controller, connect the corresponding individual cell to the charging circuit or bypass it from the charging circuit.

3. The battery pack active balancing system according to claim 2, characterized in that, The reconfigurable switching circuit includes a first switch and a second switch connected in parallel with each individual battery cell; wherein, when the first switch is closed and the second switch is open, the corresponding individual battery cell is connected to the charging circuit; when the first switch is open and the second switch is closed, the corresponding individual battery cell is bypassed from the charging circuit.

4. The battery pack active balancing system according to claim 2, characterized in that, The controller is configured to execute a voltage balancing strategy based on a consensus algorithm during the charging phase; The voltage equalization strategy includes: A single cell is identified as a reference node, the voltage error between the remaining single cells and the reference node is calculated, and the state of each of the reconfigurable switching circuits is controlled based on the voltage error.

5. The battery pack active balancing system according to claim 1, characterized in that, The second equalization module includes multiple buck-boost converter circuit units, each buck-boost converter circuit unit is disposed between two adjacent single cells, and each buck-boost converter circuit unit is used to realize bidirectional energy transfer between the corresponding two single cells.

6. The battery pack active balancing system according to claim 1, characterized in that, The controller is configured to: After charging is stopped, the battery pack is left to stand still for a preset time, and then the voltage of each individual battery cell is collected. The voltage difference is calculated based on the voltage of each individual cell, and when the voltage difference exceeds a preset threshold, it is determined that there is a voltage difference caused by polarization effect, and the second equalization module is controlled to perform a re-equalization operation.

7. The battery pack active balancing system according to claim 6, characterized in that, The controller is configured to: When controlling the second equalization module to perform the re-equalization operation, the switching transistors in each buck-boost converter circuit unit are controlled to operate with a preset duty cycle, so that they operate in continuous conduction mode.

8. The battery pack active balancing system according to claim 1, characterized in that, During the charging phase, the battery pack is charged using a constant current charging method.

9. The battery pack active balancing system according to claim 6, characterized in that, The controller is configured to: After the second equalization module performs the re-equalization operation, the voltage of each individual cell is collected again, and it is determined whether the equalization target has been achieved. If the equilibrium target is not achieved, the second equilibrium module is controlled to perform a re-equilibrium operation again until the equilibrium target is achieved. The equalization target includes a voltage difference below a preset threshold or the number of re-equalization operations reaching a preset threshold.

10. A battery pack active balancing method, characterized in that, The battery pack active balancing system applied to any one of claims 1-9 includes: During the charging phase of the battery pack, the circuit topology of the battery pack is dynamically adjusted to perform charging equalization operations on individual cells. After the battery pack is charged, monitor the voltage of each individual cell to determine if there are voltage differences due to polarization effects. If the voltage difference is determined to exist, a rebalancing operation is performed on each individual cell by transferring energy between adjacent individual cells.

11. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores a computer program that, when executed by a processor, performs the active battery pack balancing method as described in claim 10.

12. A vehicle, characterized in that, Includes the active battery pack balancing system as described in any one of claims 1-9.

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