Reconfigurable battery equalization architecture and equalization method for energy storage system

Abstract

The invention discloses an energy storage system-oriented reconfigurable battery equalization architecture and an equalization method. The equalization architecture comprises a battery module, a battery selection module, a polarity and voltage regulation module and a high-voltage gain reconfigurable module, the polarity and voltage regulation module and the high-voltage gain reconfigurable module form a two-stage equalization circuit; the battery module is formed by connecting a plurality of single batteries in series; the two ends of each single battery are respectively connected with one selection switch, and the adjacent single batteries share a battery selection module formed by one selection switch; two ends of the single battery are connected to an input port of the polarity and voltage regulation module through the battery selection module, an output port of the polarity and voltage regulation module is connected to the high-voltage gain reconfigurable module through an equalization bus, and a secondary side of the high-voltage gain reconfigurable module is connected to the whole battery module. Compared with a fixed equalization structure, the equalization architecture provided by the invention has the advantage that the reliability and efficiency of the system are greatly improved.

Description

Technical Field

[0001] The present invention relates to the technical field of energy storage systems, and in particular to a reconfigurable battery balancing architecture and a balancing method for energy storage systems. Background Art

[0002] In high-power applications such as electric vehicles and energy storage devices, lithium-ion battery packs must be designed to meet specific voltage and power level requirements. These batteries are typically connected in series. However, performance inconsistencies between individual cells are inevitable, and these variations are exacerbated by aging during battery cycling. This directly results in a decrease in the battery pack's available capacity, a reduction in cycle life, and, in extreme cases, even safety incidents such as thermal runaway. Therefore, the introduction of cell balancing management technology is crucial for improving battery pack performance, extending service life, and ensuring safe system operation.

[0003] Current mainstream active balancing circuits mostly utilize fixed-structure converters, such as flyback and buck-boost topologies. These circuits are limited by factors such as the voltage and current stress constraints of switching devices, the complexity of control algorithms, and system stability. Without special optimization, their voltage gain range is typically limited to the input voltage or within a limited boost range. Reconfigurable converters, which adjust the converter's gain range by switching switching devices, are gaining increasing attention in battery balancing systems. However, this characteristic makes them difficult to apply to balancing systems with long series battery packs.

[0004] Patent application publication number CN119209808A discloses a battery balancing system and control method based on a series-parallel reconfigurable topology. The system introduces a reconfigurable structure consisting of a gating switch and a flyback converter, combined with a balancing algorithm to achieve balancing of series-connected battery packs. However, due to the inherent voltage gain limitations of the flyback converter, balancing efficiency decreases significantly when the number of cells to be balanced differs significantly from the number of cells in the series battery pack.

[0005] Patent application CN118117693A discloses a modular, reconfigurable battery balancing circuit. The circuit combines a CUK converter with MOSFETs to create a reconfigurable structure, making it easy to expand. However, for a battery pack consisting of 4n series cells, 3n CUK converter modules and 3n-1 MOSFET switches are required. The numerous power electronic components exacerbate losses and reduce balancing efficiency.

[0006] Patent application publication number CN111555394A discloses a method for balancing a series battery pack based on a bidirectional flyback balancing circuit. While the patent mentions balancing a battery pack consisting of n cells, given the significant losses incurred by the flyback converter at high voltage gains, this solution is only practical for balancing a small number of series batteries. It is not applicable to high-power, long-series battery packs or energy storage systems.

[0007] Patent application publication number CN114844168A discloses a series battery pack balancing system and active balancing control method. It proposes a solution for balancing long series battery packs using an isolated DC / DC converter. The converter utilizes a dual-active bridge converter, with n battery cells connected in series to form the battery pack. Each battery cell is connected to the secondary side of the dual-active bridge converter via two selector switches, for a total of 2n selector switches. This solution offers the advantages of a simple structure and high converter gain. However, due to the large number of selector switches, efficiency is low in series battery packs consisting of a large number of cells, and the voltage gain of the dual-active bridge converter is insufficient to meet the requirements.

[0008] Patent application publication number CN119651847A discloses a battery energy storage system balancing device and method based on a reconfigurable converter. This patent allows for balancing of varying numbers of individual cells, ensuring that the voltage gain of the desired balanced cell matches the voltage of the battery pack. The patent's balancing structure is a single-stage structure with only one converter, resulting in a low voltage gain. The voltage gain mentioned here refers to the converter's step-up ratio, which is equal to the ratio of a single cell to the total number of cells in the battery pack. For example, if a series battery pack consists of eight cells in series, the gain is 1:8. The converter's voltage gain needs to be equal to the number of cells: the converter must operate in a state where the voltage gain matches the ratio of the cells to achieve high efficiency. Therefore, the higher the converter's voltage gain, the more cells can be connected in series in the same battery pack, resulting in higher overall balancing efficiency and lower costs. In addition, in this patent, there is an independent switch at each end of each battery. The battery is connected to the input end of the converter by closing these two switches. A total of 2n switches are required for n batteries. The entire process does not involve the reuse of switches or polarity changes. Summary of the Invention

[0009] The technical problem to be solved by the present invention is to switch the working mode according to the number of balanced batteries so that the converter is always in a high-efficiency operating state, while reducing the number of switches in the long series battery pack to reduce system loss and cost.

[0010] In order to solve the above technical problems, the present invention provides the following technical solutions:

[0011] A reconfigurable battery balancing architecture for an energy storage system includes: a battery module, a battery selection module, a polarity and voltage regulation module, and a high voltage gain reconfigurable module; and the polarity and voltage regulation module and the high voltage gain reconfigurable module form a two-stage balancing circuit;

[0012] A battery module formed by connecting multiple single cells in series; a battery selection module formed by connecting the two ends of a single cell to a selection switch, and adjacent single cells share a selection switch;

[0013] The two ends of the single battery are connected to the input port of the polarity and voltage regulation module through the battery selection module. The output port of the polarity and voltage regulation module is connected to the high voltage gain reconfigurable module through the balancing bus. The secondary side of the high voltage gain reconfigurable module is connected to the entire battery module.

[0014] Technical Effect: The entire battery module consists of n cells connected in series, with each cell connected to a selector switch at both ends. Every two adjacent cells share a selector switch, for a total of n+1 selector switches forming the battery selection module. Compared to traditional long-series battery packs requiring 2n cell selector switches, this significantly reduces the number of selector switches, thereby lowering system losses and costs. The two-stage balancing circuit, consisting of a polarity and voltage regulation module and a high-voltage gain reconfigurable module, features two gain structures. This enables the high-voltage gain reconfigurable module to achieve a voltage gain of 3m times in half-bridge mode when the converter ratio is 1:m, and a voltage gain of 6m times in full-bridge mode. Assuming the number of cells in a long-series battery module being balanced by the high-voltage gain reconfigurable module in half-bridge mode is n, the high-voltage gain reconfigurable module can balance a long-series battery module consisting of 2n cells in full-bridge mode. Switching to the corresponding mode when the number of battery modules changes ensures voltage matching throughout the balancing process, improving balancing efficiency.

[0015] In this embodiment, the polarity and voltage regulation module includes a power bridge circuit 1, an inductor L1 and a capacitor C1; and the power bridge circuit 1 includes switches S1, S2, S3 and S4;

[0016] The series-connected switches S1 and S2 are connected in parallel with the series-connected switches S3 and S4 , and the parallel connection point is connected to both ends of the series-connected inductor L1 and capacitor C1 .

[0017] In this embodiment, the high voltage gain reconfigurable module includes capacitors C2, C3, switches S5, S6, a second power bridge circuit, and a transformer T; and the second power bridge circuit includes switches S7, S8, S9, S 10 ;

[0018] The two ends of the capacitors C2 and C3 connected in series are connected to the balanced bus; and the two ends of the switches S5 and S6 connected in series, one end is connected to the capacitors C2 and C3, and the other end is connected to the power bridge circuit 2; the switches S7 and S8 connected in series are connected to the switches S9 and S 10 In parallel; the two ends of the primary side of the transformer T are connected to switches S9 and S 10 The series points of switches S7 and S8 are connected.

[0019] In this embodiment, the high voltage gain reconfigurable module has two gain structures, including gain structure I and gain structure II;

[0020] In gain structure I, switches S5 and S6 are constantly on, switches S7 and S8 are constantly off, and the primary side of the high voltage gain reconfigurable module operates in half-bridge mode.

[0021] In gain structure II, switches S5 and S6 are constantly off, and the primary side of the high voltage gain reconfigurable module operates in full-bridge mode;

[0022] If the number of single cells in the battery module balanced by the gain structure I is n, the gain structure II can achieve balancing in the battery module consisting of 2n single cells.

[0023] The present invention also provides a reconfigurable battery balancing method for an energy storage system, which applies the above-mentioned reconfigurable battery balancing architecture for an energy storage system to perform two-level balancing management, including:

[0024] Collect the SOC value of each single cell in the battery module and calculate the average SOC value of the battery module; if the difference between the SOC value of a single cell and the average SOC value exceeds the preset threshold, the single cell is determined to be in an unbalanced state and requires balancing management;

[0025] According to the real-time determination of the balancing order that requires balancing management, the selection switches corresponding to the individual cells in the unbalanced state in the battery selection module are turned on in sequence, and the individual cells in the unbalanced state are connected to the input end of the polarity and voltage regulation module;

[0026] The polarity and the operating mode of the voltage regulation module and the high voltage gain reconfigurable module are determined based on whether the sequence number of the balancing order is odd or even, and the positive or negative difference between the SOC of the single battery to be balanced and the average SOC of the battery module.

[0027] Technical Effect: The polarity and voltage regulation module connects the cells to be balanced via selector switches on either side of the cells. By adjusting the switching signals of the polarity and voltage regulation module, the voltage on both sides of the balancing busbar is kept constant at a positive value. Simultaneously, the difference between the SOC of the cells to be balanced and the average SOC of the battery module determines whether the cells to be balanced need to be charged or discharged, thereby determining the operating mode of the high-voltage gain reconfigurable module.

[0028] In this embodiment, when the balancing sequence corresponding to the cell to be balanced is an odd number, the polarity and voltage regulation module does not change the polarity of the input voltage. Simultaneously, the module determines the sign of the difference between the SOC of the cell to be balanced and the average SOC of the battery module. If the difference is positive, the module operates in an overvoltage odd-numbered cell balancing mode, releasing the energy of the cell to be balanced to the entire battery module. If the difference is negative, the module operates in an undervoltage odd-numbered cell balancing mode, transferring the energy of the battery module to the cell to be balanced. By determining the number of cells in the entire series battery module and adjusting the operating mode of the high-voltage gain reconfigurable module accordingly, the module ensures that the voltage gain corresponds to that of the long series battery module throughout the balancing process, achieving high efficiency throughout the balancing process and ultimately achieving SOC balancing for the entire long series battery module.

[0029] In this embodiment, when the number of single cells in the battery module is n, in the balancing overvoltage odd-numbered cell mode:

[0030] The selection switches connected to both ends of the single battery to be balanced are connected to both sides of the capacitor C1. At this time, switches S1 and S3 are turned on, and switches S2 and S4 are turned off. The single battery to be balanced releases energy to the capacitor C1.

[0031] When capacitor C1 is fully charged, switches S2 and S3 are turned on, switches S1 and S4 are turned off, and the polarity and voltage regulation module is connected to the high-voltage gain reconfigurable module through the balancing bus. At this time, the high-voltage gain reconfigurable module operates in gain structure I, and energy is released to the entire battery module through the secondary side of transformer T until the SOC value of the single battery to be balanced drops to the average SOC value of the battery module.

[0032] Also, when the number of single cells in the battery module is 2n, in the balanced overvoltage odd-numbered cell mode:

[0033] The selection switches connected to both ends of the single battery to be balanced are connected to both sides of the capacitor C1. At this time, switches S1 and S3 are turned on, and switches S2 and S4 are turned off. The single battery to be balanced releases energy to the capacitor C1.

[0034] When capacitor C1 is fully charged, switches S2 and S3 are turned on, switches S1 and S4 are turned off, and the polarity and voltage regulation module is connected to the high-voltage gain reconfigurable module through the balancing bus. At this time, the high-voltage gain reconfigurable module operates in gain structure II, and energy is released to the entire battery module through the secondary side of transformer T until the SOC value of the single battery to be balanced drops to the average SOC value of the battery module.

[0035] In this embodiment, when the number of single cells in the battery module is n, in the balancing undervoltage odd-numbered cell mode:

[0036] The selection switches connected at both ends of the single battery to be balanced are connected to both sides of capacitor C1. At this time, switches S2 and S3 are turned on, and switches S1 and S4 are turned off. The polarity and voltage regulation module is connected to the high voltage gain reconfigurable module through the balancing bus. The high voltage gain reconfigurable module operates in gain structure I. The energy path is the battery module, the secondary side of the transformer T, the primary side, and capacitor C1 in sequence. The energy is released to the single battery to be balanced through capacitor C1.

[0037] When the capacitor C1 is fully charged, switches S1 and S3 are turned on, and switches S2 and S4 are turned off, and energy continues to be released to the single cell to be balanced through the capacitor C1 until the SOC value of the single cell to be balanced reaches the average SOC value of the battery module.

[0038] When the number of single cells in the battery module is 2n, in the balancing undervoltage odd-numbered cell mode:

[0039] The selection switches connected at both ends of the single battery to be balanced are connected to both sides of capacitor C1. At this time, switches S2 and S3 are turned on, and switches S1 and S4 are turned off. The polarity and voltage regulation module is connected to the high voltage gain reconfigurable module through the balancing bus. The high voltage gain reconfigurable module operates in gain structure II. The energy path is the battery module, the secondary side of the transformer T, the primary side, and capacitor C1 in sequence. The energy is released to the single battery to be balanced through capacitor C1.

[0040] When the capacitor C1 is fully charged, switches S1 and S3 are turned on, and switches S2 and S4 are turned off, and energy continues to be released to the single cell to be balanced through the capacitor C1 until the SOC value of the single cell to be balanced reaches the average SOC value of the battery module.

[0041] In this embodiment, when the balancing sequence number corresponding to the single cell to be balanced is an even number, the positive or negative sign of the difference between the SOC of the single cell to be balanced and the average SOC of the battery module is determined. If the difference is positive, the operating mode at this time is the balancing overvoltage even cell mode, and the polarity of the input voltage is changed by the polarity and voltage regulation module to ensure that the polarity of the balancing bus voltage remains unchanged, and the energy of the single cell to be balanced is released to the entire battery module. If the difference is negative, the operating mode at this time is the balancing undervoltage even cell mode, and the energy of the battery module is transferred to the single cell with balancing.

[0042] In this embodiment, when the number of single cells in the battery module is n, in the balanced overvoltage even-numbered cell mode:

[0043] The selection switches connected to both ends of the single battery to be balanced are connected to both sides of the capacitor C1. At this time, switches S1 and S3 are turned on, and switches S2 and S4 are turned off. The single battery to be balanced releases energy to the capacitor C1.

[0044] When capacitor C1 is fully charged, switches S1 and S4 are turned on, and switches S2 and S3 are turned off. The polarity and voltage regulation module adjusts the input voltage polarity from negative to positive. The polarity and voltage regulation module is connected to the high-voltage gain reconfigurable module through the balancing bus. At this time, the high-voltage gain reconfigurable module operates in gain structure I, and energy is released to the entire battery module through the secondary side of transformer T until the SOC value of the single battery to be balanced drops to the average SOC value of the battery module.

[0045] Also, when the number of single cells in the battery module is 2n, in the balanced overvoltage even-numbered cell mode:

[0046] The selection switches connected to both ends of the single battery to be balanced are connected to both sides of the capacitor C1. At this time, switches S1 and S3 are turned on, and switches S2 and S4 are turned off. The single battery to be balanced releases energy to the capacitor C1.

[0047] When capacitor C1 is fully charged, switches S1 and S4 are turned on, switches S2 and S3 are turned off, and the polarity and voltage regulation module adjusts the input voltage polarity from negative to positive. The polarity and voltage regulation module is connected to the high-voltage gain reconfigurable module through the balancing bus. At this time, the high-voltage gain reconfigurable module operates in gain structure II, and energy is released to the entire battery module through the secondary side of transformer T until the SOC value of the single battery to be balanced drops to the average SOC value of the battery module.

[0048] In this embodiment, when the number of single cells in the battery module is n, in the balanced under- and over-voltage even-numbered cell mode:

[0049] The selection switches connected at both ends of the single battery to be balanced are connected to both sides of the capacitor C1. At this time, switches S1 and S4 are turned on, and switches S2 and S3 are turned off. The polarity and voltage regulation module is connected to the high voltage gain reconfigurable module through the balancing bus. The high voltage gain reconfigurable module operates in gain structure I. The energy path is the battery module, the secondary side of the transformer T, the primary side, and the capacitor C1. The energy is released to the single battery to be balanced through the capacitor C1.

[0050] When the capacitor C1 is fully charged, switches S1 and S3 are turned on, and switches S2 and S4 are turned off, and energy continues to be released to the single cell to be balanced through the capacitor C1 until the SOC value of the single cell to be balanced reaches the average SOC value of the battery module.

[0051] When the number of single cells in the battery module is 2n, in the balanced under- and over-voltage even-numbered cell mode:

[0052] The selection switches connected at both ends of the single battery to be balanced are connected to both sides of capacitor C1, S1 and S4 are turned on, switches S2 and S3 are turned off, and the polarity and voltage regulation module is connected to the high voltage gain reconfigurable module through the balancing bus. The high voltage gain reconfigurable module operates in gain structure II. The energy path is the battery module, the secondary side of the transformer T, the primary side, and capacitor C1 in sequence. Energy is released to the single battery to be balanced through capacitor C1;

[0053] When the capacitor C1 is fully charged, switches S1 and S3 are turned on, and switches S2 and S4 are turned off, and energy continues to be released to the single cell to be balanced through the capacitor C1 until the SOC value of the single cell to be balanced reaches the average SOC value of the battery module.

[0054] Compared with the prior art, the present invention has the following beneficial effects:

[0055] The balancing architecture of the present invention can switch operating modes according to the number of different single-cell batteries in the battery module, and is applicable to various long-series battery modules. It has strong versatility and significantly improves system balancing efficiency compared to traditional fixed balancing structures. It realizes the function of switching high-voltage gain reconfigurable modules according to the number of long-series battery modules, reducing system losses and improving balancing efficiency. In addition, the polarity and voltage regulation module can ensure that the voltage polarity on both sides of the balancing bus is constant. Therefore, the battery selection module can be composed of n+1 selection switches. Compared with the traditional long-series battery pack connected to 2n battery selection switches, the number of selection switches is greatly reduced, reducing system losses. In addition, the two-stage balancing structure can achieve extremely high voltage gain, which can realize the balancing of long-series battery packs for high-power applications. At the same time, the architecture has strong adaptability, enhancing the flexibility and scalability of the balancing system. In general, the reconfigurable battery balancing architecture proposed by the present invention solves the problem of efficient balancing of long-series battery packs and is suitable for efficient balancing management of large-scale battery packs.

[0056] The controller adjusts the shift phase d of the primary-to-secondary switches of the high-voltage gain reconfigurable module to stabilize the charge and discharge of the target battery. When the shift phase d is positive, the converter operates in discharge mode, with converter energy flowing from the primary to the secondary, delivering the battery charge to both ends of the battery pack to achieve battery discharge. When the shift phase d is negative, the converter operates in charge mode, with the high-voltage gain reconfigurable module energy flowing from the secondary to the primary, delivering the battery charge to both ends of the battery pack to achieve battery charging, thereby achieving stable SOC balance within the battery pack. BRIEF DESCRIPTION OF THE DRAWINGS

[0057] Figure 1 Schematic diagram of a reconfigurable battery balancing architecture for an energy storage system according to an embodiment of the present invention.

[0058] FIG2( a ) is a schematic diagram of a gain structure I according to an embodiment of the present invention.

[0059] FIG2( b ) is a schematic diagram of a gain structure II according to an embodiment of the present invention.

[0060] Figure 3(a) 、 3(b) Schematic diagram of an overvoltage odd-number battery mode of balancing in two stages when the number of single battery cells is n according to an embodiment of the present invention.

[0061] Figure 4(a) 、 4(b) Schematic diagram of an overvoltage odd-number battery mode of balancing in two stages when the number of single battery cells is 2n according to an embodiment of the present invention.

[0062] Figure 5(a) 、 5(b)A schematic diagram of a two-stage mode for balancing undervoltage odd-numbered cells when the number of single cells is n according to an embodiment of the present invention.

[0063] Figure 6(a) 、 6(b) Schematic diagram of a two-stage mode for balancing undervoltage odd-numbered cells when the number of single cells is 2n according to an embodiment of the present invention.

[0064] Figure 7(a) 、 7(b) Schematic diagram of an even-numbered battery mode for balancing overvoltage in two stages when the number of single battery cells is n according to an embodiment of the present invention.

[0065] Figure 8(a) 、 8(b) Schematic diagram of a two-stage balancing overvoltage even-numbered battery mode when the number of single battery cells is 2n according to an embodiment of the present invention.

[0066] Figure 9(a) 、 9(b) Schematic diagram of a two-stage balancing under- and over-voltage even-numbered battery mode when the number of single battery cells is n according to an embodiment of the present invention.

[0067] Figure 10(a) 、 10(b) Schematic diagram of a two-stage balancing mode for under- and over-voltage even-numbered cells when the number of single cells is 2n according to an embodiment of the present invention. DETAILED DESCRIPTION

[0068] To facilitate those skilled in the art to understand the technical solution of the present invention, the technical solution of the present invention is further described with reference to the accompanying drawings.

[0069] The terms "first" and "second" are used for descriptive purposes only and should not be understood to indicate or imply relative importance or implicitly specify the number of the technical features indicated. Therefore, a feature specified as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of this application, "plurality" means two or more, unless otherwise specifically defined.

[0070] Example 1

[0071] See also Figure 1 As shown, the present invention provides a reconfigurable battery balancing architecture for energy storage systems, including a battery module, a battery selection module, a polarity and voltage regulation module, and a high-voltage gain reconfigurable module. Furthermore, the polarity and voltage regulation module and the high-voltage gain reconfigurable module form a two-stage balancing circuit.

[0072] In this embodiment, a battery module is formed by connecting multiple single cells in series. Each end of a single cell is connected to a selector switch, and adjacent single cells share a selector switch to form a battery selection module. Specifically, when the number of single cells in a battery module is n, the number of selector switches in the battery selection module is n+1. When the number of single cells in a battery module is 2n, the number of selector switches in the battery selection module is 2n+1. Therefore, compared to a traditional long series battery pack with n single cells connected to 2n battery selector switches, the present invention significantly reduces the number of selector switches, reduces system losses, and reduces costs.

[0073] See also Figure 2(a) 、 2(b) As shown, in one embodiment of the present invention, the polarity and voltage regulation module can ensure constant voltage polarity on both sides of the balanced bus. Specifically, the polarity and voltage regulation module includes a power bridge circuit 1, an inductor L1, and a capacitor C1. Furthermore, the power bridge circuit 1 includes switches S1, S2, S3, and S4. The series connection of switches S1 and S2 is connected in parallel with the series connection of switches S3 and S4, and the parallel connection point is connected to the two ends of the series connection of inductor L1 and capacitor C1.

[0074] See also Figure 2(a) 、 2(b) As shown, in one embodiment of the present invention, the high voltage gain reconfigurable module includes capacitors C2, C3, switches S5, S6, a power bridge circuit 2, a transformer T, and the power bridge circuit 2 includes switches S7, S8, S9, S 10 The two ends of the capacitors C2 and C3 connected in series are connected to the balanced bus, and the two ends of the switches S5 and S6 connected in series, one end is connected to the capacitors C2 and C3, and the other end is connected to the power bridge circuit 2. The switches S7 and S8 connected in series are connected to the switches S9 and S6 connected in series. 10 In parallel, the two ends of the primary side of the transformer T are connected to switches S9 and S 10 The series points of switches S7 and S8 are connected.

[0075] In this embodiment, the high-voltage-gain reconfigurable module, combined with the polarity and voltage regulation module, has two gain structures: Gain Structure I and Gain Structure II. The polarity and voltage regulation module operates in Boost mode. Under non-ideal conditions, the voltage gain is Q (depending on the actual circuit parameters; in practice, Q < 4). In Gain Structure I, switches S5 and S6 are constantly on, while switches S7 and S8 are constantly off. The primary side of the high-voltage-gain reconfigurable module operates in half-bridge mode. When the transformer T ratio is 1:m, a voltage gain of 3m can be achieved. In Gain Structure II, switches S5 and S6 are constantly off, and the primary side of the high-voltage-gain reconfigurable module operates in full-bridge mode. When the transformer T ratio is 1:m, a voltage gain of 6m can be achieved. Therefore, assuming that the number of cells in the long series battery module balanced by Gain Structure I is n, Gain Structure II can balance a long series battery module consisting of 2n cells. When the number of battery modules changes, the corresponding mode is switched to achieve voltage matching during the full balancing process, thereby improving balancing efficiency. The present invention can adapt to most high-power applications of long series battery packs and has good applicability.

[0076] Example 2

[0077] See also Figures 1 to 2(b) As shown, the present invention also provides a reconfigurable battery balancing method for an energy storage system, which applies the reconfigurable battery balancing architecture for an energy storage system described in Example 1 to perform two-level balancing management, including:

[0078] S10, collecting the SOC value of each single cell in the battery module and calculating the average SOC value of the battery module; if the difference between the SOC value of a single cell and the average SOC value exceeds a preset threshold, the single cell is determined to be in an unbalanced state and requires balancing management.

[0079] In this embodiment, the main controller receives the SOC value of each cell in the battery module from the SOC acquisition circuit via data communication and calculates the difference between each cell's SOC value and the average SOC value of the battery pack. Furthermore, the main controller receives sampled values ​​from the charge and discharge current sampling circuit via data communication, which can be used to adjust the charge and discharge rates during battery balancing.

[0080] S20 , according to the real-time determination of the balancing order requiring balancing management, sequentially turning on the selection switches corresponding to the individual cells in the unbalanced state in the battery selection module, and connecting the individual cells in the unbalanced state to the input end of the polarity and voltage regulation module.

[0081] In this embodiment, the main controller sequentially turns on the selection switches corresponding to the unbalanced cells in the battery selection module through the driving circuit according to the real-time determined balancing order, and connects the unbalanced cells to the input end of the transformer T.

[0082] S30 , determining the polarity and the operating mode of the voltage regulation module and the high voltage gain reconfigurable module according to whether the sequence number of the balancing order is odd or even, and the positive or negative difference between the SOC of the single battery to be balanced and the average SOC of the battery module.

[0083] In this embodiment, the difference between the SOC of the battery to be balanced and the average SOC of the battery module is positive or negative, and the battery is judged to be in a discharging or charging state. The controller adjusts the shift ratio d of the transformer T. When d < 0, the battery to be balanced is in a stable charging state. When d > 0, the battery to be balanced is in a stable discharging state.

[0084] In this embodiment, the main controller can be divided into four operating modes based on the number of cells in the battery module connected to the two-stage balancing circuit via the battery selection module: balancing overvoltage odd-number cell mode, balancing undervoltage odd-number cell mode, balancing overvoltage even-number cell mode, and balancing under-overvoltage even-number cell mode. Each operating mode is further divided into two modes: one with n cells and one with 2n cells. This can also be understood as connecting a battery module with one cell number of n, or connecting two battery modules with n cells. The specific implementation methods of these four operating states are described below.

[0085] See also Figures 3(a) to 6(b) As shown, in one embodiment of the present invention, when the balancing sequence corresponding to the single cell to be balanced is an odd number, the polarity and voltage regulation module does not change the polarity of the input voltage. At the same time, the positive or negative difference between the SOC of the single cell to be balanced and the average SOC of the battery module is determined. If the difference is positive, the operating mode is the overvoltage odd cell balancing mode, releasing the energy of the single cell to be balanced to the entire battery module. If the difference is negative, the operating mode is the undervoltage odd cell balancing mode, transferring the energy of the battery module to the single cell to be balanced.

[0086] See also Figure 3(a) 、 3(b) As shown, in this embodiment, when the number of cells in the battery module is n, in the overvoltage odd-number cell balancing mode, the shift phase d of the high-voltage gain reconfigurable module is greater than 0, releasing the energy of the cell to be balanced in the battery module to the entire long series battery module. In this case, the cell to be balanced is an overcharged cell.

[0087] Assuming that the single cell B1 is an overcharged battery, in the first stage of the equalization management, the single cell B1 selects the switch S c1 、S c2 Connected to both sides of capacitor C1 in the polarity and voltage regulation module, at this time, switches S2 and S3 are turned on, S1 and S4 are turned off, and the single battery B1 releases energy to capacitor C1. The energy is released to the secondary side of the transformer T and fed back to the battery module.

[0088] When capacitor C1 is fully charged, balancing management transitions from the first stage to the second stage. At this point, switches S2 and S3 are turned on, switches S1 and S4 are turned off, and the polarity and voltage regulation module is connected to the high-voltage gain reconfigurable module via the balancing bus. At this point, the high-voltage gain reconfigurable module operates in gain configuration I, releasing energy to the entire battery module through the secondary side of transformer T until the SOC of the battery being balanced drops to the average SOC of the battery module.

[0089] See also Figure 4(a) 、 4(b) As shown, in this embodiment, the above balancing process is also applicable to a battery module composed of 2n single cells, and the sequence number of the overcharged battery is an odd number. At this time, the high voltage gain reconfigurable module releases energy to the entire battery module through the gain structure II.

[0090] In this embodiment, specifically, when the number of single cells in the battery module is 2n, then in the overvoltage balancing odd-numbered cell mode:

[0091] The selection switches connected at both ends of the single battery to be balanced are connected to both sides of the capacitor C1. At this time, switches S1 and S3 are turned on, and switches S2 and S4 are turned off. The single battery to be balanced releases energy to the capacitor C1.

[0092] When capacitor C1 is fully charged, switches S2 and S3 are turned on, switches S1 and S4 are turned off, and the polarity and voltage regulation module is connected to the high-voltage gain reconfigurable module through the balancing bus. At this time, the high-voltage gain reconfigurable module operates in gain structure II, and energy is released to the entire battery module through the secondary side of transformer T until the SOC value of the single battery to be balanced drops to the average SOC value of the battery module.

[0093] See also Figure 5(a) 、 5(b) As shown, in this embodiment, for a battery module consisting of n cells, when the difference between the SOC value of an odd-numbered cell in the battery module and the average SOC value of the battery module is greater than a preset minimum balancing threshold, the balancing architecture will operate in the undervoltage odd-cell balancing mode. At this time, the shift phase d of the high-voltage gain reconfigurable module is less than 0, and the energy of the entire battery module is transferred to the undercharged odd-numbered cell.

[0094] In this embodiment, it is assumed that the single cell B1 to be balanced is an undercharged battery. In the first stage of the balancing management, the single cell B1 is switched to c1 、S c2 Connected to both sides of the capacitor C1 in the polarity and voltage regulation module, at this time, switches S2 and S3 are turned on, switches S1 and S4 are turned off, and the polarity and voltage regulation module is connected to the high voltage gain reconfigurable module through the balancing bus. The high voltage gain reconfigurable module works in gain structure I and releases energy to the input capacitor C1. The energy path is the battery module, the secondary side of the transformer T, the primary side, and the capacitor C1 in sequence. The energy is released to the single battery B1 to be balanced through the capacitor C1.

[0095] When capacitor C1 is fully charged, the balancing management changes from the first stage to the second stage. At this time, switches S1 and S3 are turned on, and switches S2 and S4 are turned off. Energy continues to be released to the undercharged single battery B1 through capacitor C1 until the SOC value of single battery B1 rises to the average SOC value of the battery module.

[0096] See also Figure 6(a) 、 6(b) As shown, in this embodiment, the above balancing process is also applicable to a battery module composed of 2n single cells, and the undercharged batteries with odd serial numbers. At this time, the high voltage gain reconfigurable module releases energy to the entire battery module through the gain structure II.

[0097] In this embodiment, specifically, when the number of single cells in the battery module is 2n, then in the balancing undervoltage odd-numbered cell mode:

[0098] The selection switches connected at both ends of the single battery to be balanced are connected to both sides of the capacitor C1. At this time, switches S2 and S3 are turned on, switches S1 and S4 are turned off, and the polarity and voltage regulation module is connected to the high voltage gain reconfigurable module through the balancing bus. The high voltage gain reconfigurable module operates in gain structure II. The energy path is the battery module, the secondary side of the transformer, the primary side, and capacitor C1 in sequence. The energy is released to the single battery to be balanced through capacitor C1.

[0099] When the capacitor C1 is fully charged, switches S1 and S3 are turned on, and switches S2 and S4 are turned off, and energy continues to be released to the single cell to be balanced through the capacitor C1 until the SOC value of the single cell to be balanced reaches the average SOC value of the battery module.

[0100] Referring to Figures 7(a) to 10(b), in one embodiment of the present invention, when the balancing sequence number corresponding to the single cell to be balanced is an even number, the positive or negative sign of the difference between the SOC of the single cell to be balanced and the average SOC of the battery module is determined. If the difference is positive, the operating mode at this time is the balancing overvoltage even cell mode, and the polarity of the input voltage is changed by the polarity and voltage regulation module to ensure that the polarity of the balancing bus voltage remains unchanged, and the energy of the single cell to be balanced is released to the entire battery module. If the difference is negative, the operating mode at this time is the balancing undervoltage even cell mode, and the energy of the battery module is transferred to the single cell with balancing.

[0101] See also Figure 7(a) 、 7(b) As shown in the figure, in this embodiment, for a battery module consisting of n cells, when the difference between the SOC value of an even-numbered cell in the battery module and the average SOC value of the battery module is greater than the preset maximum balancing threshold, the balancing management will operate in the balancing overvoltage even-numbered cell mode. At this time, the shift phase d of the high voltage gain reconfigurable module is greater than 0, releasing the energy of the overcharged cell in the battery module to the entire battery module. Assuming that cell B2 is an overcharged cell, in the first stage of balancing management, cell B2 selects switch S c2 、S c3 Connected to both sides of the capacitor C1 in the polarity and voltage regulation module, at this time, switches S1 and S3 are turned on, switches S2 and S4 are turned off, and the single battery B2 releases energy to the capacitor C1. The energy is released to the secondary side of the transformer T and fed back to the battery module.

[0102] When capacitor C1 is fully charged, balancing management transitions from the first stage to the second stage. At this point, switches S1 and S4 are turned on, while switches S2 and S3 are turned off. The polarity and voltage regulation module adjusts the input voltage polarity from negative to positive, ensuring that the polarity of the balancing bus voltage remains unchanged. The polarity and voltage regulation module is connected to the high-voltage gain reconfigurable module via the balancing bus. At this point, the high-voltage gain reconfigurable module operates in gain configuration I, releasing energy to the entire battery module through the secondary side of transformer T until the average SOC value of the battery module is reached for cell B2.

[0103] In this embodiment, the polarity and voltage regulation module adjusts the input voltage polarity from negative to positive in the following process: in stage one, the voltage polarity of capacitor C1 is "positive at the bottom and negative at the top"; in stage two, switches S1 and S4 are turned on. At this time, the upper end of the balancing bus (the upper side of capacitor C2) and the lower end of capacitor C1 are at the same potential, which is positive; the lower end of the balancing bus (the lower side of capacitor C3) and the upper end of capacitor C1 are at the same potential, which is negative.

[0104] See also Figure 8(a) 、 8(b)As shown, in this embodiment, the above balancing process is also applicable to a battery module composed of 2n single cells, and the overcharged batteries with odd serial numbers, at this time the high voltage gain reconfigurable module releases energy to the entire battery pack through the gain structure II.

[0105] In this embodiment, specifically, when the number of single cells in the battery module is 2n, then in the balanced overvoltage even-numbered cell mode:

[0106] The selection switches connected at both ends of the single battery to be balanced are connected to both sides of the capacitor C1. At this time, switches S1 and S3 are turned on, and switches S2 and S4 are turned off. The single battery to be balanced releases energy to the capacitor C1.

[0107] When capacitor C1 is fully charged, switches S1 and S4 are turned on, switches S2 and S3 are turned off, and the polarity and voltage regulation module adjusts the input voltage polarity from negative to positive. The polarity and voltage regulation module is connected to the high-voltage gain reconfigurable module through the balancing bus. At this time, the high-voltage gain reconfigurable module operates in gain structure II, and energy is released to the entire battery module through the secondary side of transformer T until the SOC value of the single battery to be balanced drops to the average SOC value of the battery module.

[0108] See also Figure 9(a) 、 9(b) As shown in the figure, in this embodiment, for a battery module consisting of n cells, when the difference between the SOC value of the cell with an even sequence number in the battery module and the average SOC value of the battery module is greater than the preset minimum balancing threshold, the balancing management system will operate in the balancing undervoltage even-numbered cell mode. At this time, the shift phase d of the high voltage gain reconfigurable module is less than 0, and the energy of the entire battery module is transferred to the undercharged even-numbered cell. Assuming that cell B2 is an undercharged cell, the balancing management is in the first stage. Cell B2 is switched to the undercharged even-numbered cell mode. c2 、S c3 Connected to both sides of the capacitor C1 in the polarity and voltage regulation module. At this time, switches S1 and S4 are turned on, switches S2 and S3 are turned off, and the polarity and voltage regulation module is connected to the high voltage gain reconfigurable module through the balancing bus. The energy path is the battery module, the secondary side of the transformer T, the primary side, and the capacitor C1 in sequence. The energy is released to the single battery B2 through the capacitor C1.

[0109] When capacitor C1 is fully charged, the balancing management switches from the first stage to the second stage. At this time, switches S1 and S3 are turned on, and switches S2 and S4 are turned off. Energy continues to be released to single battery B2 through capacitor C1 until the SOC value of single battery B2 rises to the average SOC value of the battery module.

[0110] See also Figure 10(a) 、 10(b)As shown, in this embodiment, the above balancing process is also applicable to the battery module composed of 2n single cells, and the undercharged batteries with even serial numbers. At this time, the high voltage gain reconfigurable module releases energy to the entire battery pack through the gain structure II.

[0111] In this embodiment, specifically, when the number of single cells in the battery module is 2n, then in the balanced under- and over-voltage even-numbered cell mode:

[0112] The selection switches connected at both ends of the single battery to be balanced are connected to both sides of the capacitor C1, S1 and S4 are turned on, switches S2 and S3 are turned off, and the polarity and voltage regulation module is connected to the high voltage gain reconfigurable module through the balancing bus. The high voltage gain reconfigurable module operates in gain structure II. The energy path is the battery module, the secondary side of the transformer T, the primary side, and the capacitor C1 in sequence. The energy is released to the single battery to be balanced through the capacitor C1.

[0113] When the capacitor C1 is fully charged, switches S1 and S3 are turned on, and switches S2 and S4 are turned off, and energy continues to be released to the single cell to be balanced through the capacitor C1 until the SOC value of the single cell to be balanced reaches the average SOC value of the battery module.

[0114] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above and that the invention can be embodied in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments should be considered in all respects as illustrative and non-restrictive, and the scope of the invention is defined by the appended claims rather than the foregoing description. It is intended that all variations within the meaning and range of equivalents of the claims be embraced herein, and any reference signs in the claims should not be construed as limiting the claims to which they relate.

[0115] The above-mentioned embodiments merely represent the implementation methods of the invention. The protection scope of the present invention is not limited to the above-mentioned embodiments. For those skilled in the art, several variations and improvements can be made without departing from the concept of the present invention, which all fall within the protection scope of the present invention.

Claims

1. A reconfigurable battery balancing architecture for energy storage systems, characterized in that: include: Battery module, battery selection module, polarity and voltage regulation module and high voltage gain reconfigurable module; Furthermore, the polarity and voltage adjustment module and the high voltage gain reconfigurable module constitute a two-stage balancing circuit; A battery module formed by connecting multiple single cells in series; a battery selection module formed by connecting the two ends of a single cell to a selection switch, and adjacent single cells share a selection switch; The two ends of the single battery are connected to the input port of the polarity and voltage regulation module through the battery selection module. The output port of the polarity and voltage regulation module is connected to the high voltage gain reconfigurable module through the balancing bus. The secondary side of the high voltage gain reconfigurable module is connected to the entire battery module.

2. The reconfigurable battery balancing architecture for energy storage systems according to claim 1, characterized in that: The polarity and voltage regulation module includes a power bridge circuit 1, an inductor L1 and a capacitor C1; and the power bridge circuit 1 includes switches S1, S2, S3 and S4; The series-connected switches S1 and S2 are connected in parallel with the series-connected switches S3 and S4, and the parallel connection point is connected to both ends of the series-connected inductor L1 and capacitor C1; The high voltage gain reconfigurable module includes capacitors C2, C3, switches S5, S6, a power bridge circuit 2, and a transformer T; and the power bridge circuit 2 includes switches S7, S8, S9, S 10 ; The two ends of the capacitors C2 and C3 connected in series are connected to the balanced bus; and the two ends of the switches S5 and S6 connected in series, one end is connected to the capacitors C2 and C3, and the other end is connected to the power bridge circuit 2; the switches S7 and S8 connected in series are connected to the switches S9 and S 10 In parallel; the two ends of the primary side of the transformer T are connected to switches S9 and S 10 The series points of switches S7 and S8 are connected.

3. The reconfigurable battery balancing architecture for energy storage systems according to claim 2, characterized in that: High voltage gain reconfigurable module with two gain structures, including gain structure I and gain structure II; In gain structure I, switches S5 and S6 are constantly on, switches S7 and S8 are constantly off, and the primary side of the high voltage gain reconfigurable module operates in half-bridge mode. In gain structure II, switches S5 and S6 are constantly off, and the primary side of the high voltage gain reconfigurable module operates in full-bridge mode; If the number of single cells in the battery module balanced by the gain structure I is n, the gain structure II can achieve balancing in the battery module consisting of 2n single cells.

4. A reconfigurable battery balancing method for energy storage systems, characterized in that: Applying the reconfigurable battery balancing architecture for energy storage systems according to any one of claims 1 to 3 to perform two-level balancing management includes: Collect the SOC value of each single cell in the battery module and calculate the average SOC value of the battery module; if the difference between the SOC value of a single cell and the average SOC value exceeds the preset threshold, the single cell is determined to be in an unbalanced state and requires balancing management; According to the real-time determination of the balancing order that requires balancing management, the selection switches corresponding to the individual cells in the unbalanced state in the battery selection module are turned on in sequence, and the individual cells in the unbalanced state are connected to the input end of the polarity and voltage regulation module; The polarity and the operating mode of the voltage regulation module and the high voltage gain reconfigurable module are determined based on whether the sequence number of the balancing order is odd or even, and the positive or negative difference between the SOC of the single battery to be balanced and the average SOC of the battery module.

5. The reconfigurable battery balancing method for energy storage system according to claim 4, characterized in that: When the balancing sequence number of the single cell to be balanced is an odd number, the polarity and voltage regulation module does not change the polarity of the input voltage. At the same time, the positive or negative difference between the SOC of the single cell to be balanced and the average SOC of the battery module is determined. If the difference is positive, the operating mode is the overvoltage odd cell balancing mode, and the energy of the single cell to be balanced is released to the entire battery module. If the difference is negative, the working mode at this time is the balancing undervoltage odd-numbered battery mode, and the energy of the battery module is transferred to the single battery with balancing.

6. The reconfigurable battery balancing method for energy storage system according to claim 5, characterized in that: When the number of single cells in the battery module is n, in the balanced overvoltage odd-numbered cell mode: The selection switches connected to both ends of the single battery to be balanced are connected to both sides of the capacitor C1. At this time, switches S1 and S3 are turned on, and switches S2 and S4 are turned off. The single battery to be balanced releases energy to the capacitor C1. When capacitor C1 is fully charged, switches S2 and S3 are turned on, switches S1 and S4 are turned off, and the polarity and voltage regulation module is connected to the high-voltage gain reconfigurable module through the balancing bus. At this time, the high-voltage gain reconfigurable module operates in gain structure I, and energy is released to the entire battery module through the secondary side of transformer T until the SOC value of the single battery to be balanced drops to the average SOC value of the battery module. Also, when the number of single cells in the battery module is 2n, in the balanced overvoltage odd-numbered cell mode: The selection switches connected to both ends of the single battery to be balanced are connected to both sides of the capacitor C1. At this time, switches S1 and S3 are turned on, and switches S2 and S4 are turned off. The single battery to be balanced releases energy to the capacitor C1. When capacitor C1 is fully charged, switches S2 and S3 are turned on, switches S1 and S4 are turned off, and the polarity and voltage regulation module is connected to the high-voltage gain reconfigurable module through the balancing bus. At this time, the high-voltage gain reconfigurable module operates in gain structure II, and energy is released to the entire battery module through the secondary side of transformer T until the SOC value of the single battery to be balanced drops to the average SOC value of the battery module.

7. The reconfigurable battery balancing method for energy storage system according to claim 5, characterized in that: When the number of single cells in the battery module is n, in the balancing undervoltage odd-numbered cell mode: The selection switches connected at both ends of the single battery to be balanced are connected to both sides of capacitor C1. At this time, switches S2 and S3 are turned on, and switches S1 and S4 are turned off. The polarity and voltage regulation module is connected to the high voltage gain reconfigurable module through the balancing bus. The high voltage gain reconfigurable module operates in gain structure I. The energy path is the battery module, the secondary side of the transformer T, the primary side, and capacitor C1 in sequence. The energy is released to the single battery to be balanced through capacitor C1. When the capacitor C1 is fully charged, switches S1 and S3 are turned on, and switches S2 and S4 are turned off, and energy continues to be released to the single cell to be balanced through the capacitor C1 until the SOC value of the single cell to be balanced reaches the average SOC value of the battery module. When the number of single cells in the battery module is 2n, in the balancing undervoltage odd-numbered cell mode: The selection switches connected at both ends of the single battery to be balanced are connected to both sides of capacitor C1. At this time, switches S2 and S3 are turned on, and switches S1 and S4 are turned off. The polarity and voltage regulation module is connected to the high voltage gain reconfigurable module through the balancing bus. The high voltage gain reconfigurable module operates in gain structure II. The energy path is the battery module, the secondary side of the transformer T, the primary side, and capacitor C1 in sequence. The energy is released to the single battery to be balanced through capacitor C1. When the capacitor C1 is fully charged, switches S1 and S3 are turned on, and switches S2 and S4 are turned off, and energy continues to be released to the single cell to be balanced through the capacitor C1 until the SOC value of the single cell to be balanced reaches the average SOC value of the battery module.

8. The reconfigurable battery balancing method for energy storage system according to claim 4, characterized in that: When the balancing sequence number of the single cell to be balanced is even, the positive or negative difference between the SOC of the single cell to be balanced and the average SOC of the battery module is determined. If the difference is positive, the working mode at this time is the balancing overvoltage even cell mode, and the polarity of the input voltage is changed through the polarity and voltage regulation module to ensure that the polarity of the balancing bus voltage remains unchanged, and the energy of the single cell to be balanced is released to the entire battery module; If the difference is negative, the working mode at this time is the balanced under-voltage and over-voltage even-numbered battery mode, and the energy of the battery module is transferred to the single battery with balancing.

9. The reconfigurable battery balancing method for energy storage system according to claim 8, characterized in that: When the number of single cells in the battery module is n, in the balanced overvoltage even-numbered cell mode: The selection switches connected to both ends of the single battery to be balanced are connected to both sides of the capacitor C1. At this time, switches S1 and S3 are turned on, and switches S2 and S4 are turned off. The single battery to be balanced releases energy to the capacitor C1. When capacitor C1 is fully charged, switches S1 and S4 are turned on, and switches S2 and S3 are turned off. The polarity and voltage regulation module adjusts the input voltage polarity from negative to positive. The polarity and voltage regulation module is connected to the high-voltage gain reconfigurable module through the balancing bus. At this time, the high-voltage gain reconfigurable module operates in gain structure I, and energy is released to the entire battery module through the secondary side of transformer T until the SOC value of the single battery to be balanced drops to the average SOC value of the battery module. Also, when the number of single cells in the battery module is 2n, in the balanced overvoltage even-numbered cell mode: The selection switches connected to both ends of the single battery to be balanced are connected to both sides of the capacitor C1. At this time, switches S1 and S3 are turned on, and switches S2 and S4 are turned off. The single battery to be balanced releases energy to the capacitor C1. When capacitor C1 is fully charged, switches S1 and S4 are turned on, switches S2 and S3 are turned off, and the polarity and voltage regulation module adjusts the input voltage polarity from negative to positive. The polarity and voltage regulation module is connected to the high-voltage gain reconfigurable module through the balancing bus. At this time, the high-voltage gain reconfigurable module operates in gain structure II, and energy is released to the entire battery module through the secondary side of transformer T until the SOC value of the single battery to be balanced drops to the average SOC value of the battery module.

10. The reconfigurable battery balancing method for energy storage system according to claim 8, characterized in that: When the number of single cells in the battery module is n, in the balanced under- and over-voltage even-numbered cell mode: The selection switches connected at both ends of the single battery to be balanced are connected to both sides of the capacitor C1. At this time, switches S1 and S4 are turned on, and switches S2 and S3 are turned off. The polarity and voltage regulation module is connected to the high voltage gain reconfigurable module through the balancing bus. The high voltage gain reconfigurable module operates in gain structure I. The energy path is the battery module, the secondary side of the transformer T, the primary side, and the capacitor C1. The energy is released to the single battery to be balanced through the capacitor C1. When the capacitor C1 is fully charged, switches S1 and S3 are turned on, and switches S2 and S4 are turned off, and energy continues to be released to the single cell to be balanced through the capacitor C1 until the SOC value of the single cell to be balanced reaches the average SOC value of the battery module. When the number of single cells in the battery module is 2n, in the balanced under- and over-voltage even-numbered cell mode: The selection switches connected at both ends of the single battery to be balanced are connected to both sides of capacitor C1, S1 and S4 are turned on, switches S2 and S3 are turned off, and the polarity and voltage regulation module is connected to the high voltage gain reconfigurable module through the balancing bus. The high voltage gain reconfigurable module operates in gain structure II. The energy path is the battery module, the secondary side of the transformer T, the primary side, and capacitor C1 in sequence. Energy is released to the single battery to be balanced through capacitor C1; When the capacitor C1 is fully charged, switches S1 and S3 are turned on, and switches S2 and S4 are turned off, and energy continues to be released to the single cell to be balanced through the capacitor C1 until the SOC value of the single cell to be balanced reaches the average SOC value of the battery module.

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