Energy storage battery equalization circuit and method, and energy storage battery equalizer

Abstract

The present application relates to an energy storage battery equalization circuit and method, and an energy storage battery equalizer. The energy storage battery equalization circuit comprises a plurality of first bidirectional equalization circuits and a plurality of second bidirectional equalization circuits. Each first bidirectional equalization circuit is correspondingly connected to a battery module and is configured to: equalize the voltage of a first battery cell and the voltage of a second battery cell in the battery module. Each second bidirectional equalization circuit is correspondingly connected to any two adjacent battery modules and is configured to: equalize the voltage of the second battery cell in a first battery module of the any two adjacent battery modules and the voltage of the first battery cell in a second battery module of the any two adjacent battery modules. The present application is used for increasing the equalization speed and efficiency and the battery utilization rate, and implementing miniaturization and modular expansion of energy storage battery equalization circuits.

Description

Energy storage battery balancing circuit and method thereof, and energy storage battery equalizer

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to the Chinese patent application filed with the China Patent Office on December 29, 2023, with application number 2023118578068, and application name “Energy Storage Battery Balancing Circuit and Method Thereof, Energy Storage Battery Equalizer”, all contents of which are incorporated by reference into this application. Technical Field

[0003] The present application relates to the field of energy storage battery balancing control, and in particular to an energy storage battery balancing circuit and method thereof, and an energy storage battery equalizer. Background Art

[0004] In recent years, with the widespread adoption of new energy industries, the utilization of lithium batteries has continued to increase. However, when using energy storage batteries, a single cell is often insufficient to meet the demands of practical applications. Therefore, to achieve higher voltage and power, multiple battery cells are typically connected in series or parallel. However, due to the deep charge and discharge characteristics of energy storage systems, the capacity consistency of cells within a battery cluster after repeated charge and discharge cycles can severely impact the available capacity of the energy storage system. Without effective measures, this can significantly reduce the reliability of the entire energy storage battery system, shorten its service life, and even pose serious safety risks. Therefore, developing a safe, efficient, and reliable battery balancing control system is crucial to improving the inconsistency between battery cells.

[0005] However, related battery balancing technologies are mainly divided into passive balancing and active balancing. Passive balancing has large balancing energy loss and low balancing efficiency, while active balancing uses more components, has high costs, and has problems such as unsatisfactory balancing speed and balancing efficiency over long distances. Summary of the Invention

[0006] Based on this, it is necessary to provide an energy storage battery balancing circuit and method thereof, and an energy storage battery equalizer, which are used to ensure that the voltages of each battery cell tend to be consistent more quickly and effectively, thereby eliminating the voltage differences between different battery cells, and easily improving the balancing speed, balancing efficiency and battery energy utilization, as well as reducing costs and circuit volume, so as to achieve miniaturization and modular expansion of the energy storage battery balancing circuit and the energy storage battery equalizer.

[0007] A storage battery balancing circuit is applied to a plurality of first battery cells and a plurality of second battery cells alternately connected in series, wherein each first battery cell and the second battery cell connected in series with it constitute a battery module. The storage battery balancing circuit comprises: a plurality of first bidirectional balancing circuits and a plurality of second bidirectional balancing circuits. The first bidirectional balancing circuits are connected to the battery modules and configured to balance the voltages of the first battery cells and the second battery cells within the battery modules. The second bidirectional balancing circuits are connected to any two adjacent battery modules and configured to balance the voltages of the second battery cells within the first of the two adjacent battery modules and the voltages of the first battery cells within the second of the two adjacent battery modules.

[0008] In some embodiments of the present disclosure, the energy storage battery balancing circuit further includes: a first switching device connected to each first battery cell, and a second switching device connected to each second battery cell. The first bidirectional balancing circuit and the second bidirectional balancing circuit share the first switching device connected to the first battery cell, and share the second switching device connected to the second battery cell.

[0009] In some embodiments of the present disclosure, the negative electrode of the first battery cell is connected to the positive electrode of the second battery cell, and the negative electrode of the second battery cell is connected to the positive electrode of the first battery cell in the adjacent battery module. The first switching device and the second switching device each have a first end and a second end. The first bidirectional balancing circuit also includes: a first energy storage capacitor and an energy storage inductor. The first energy storage capacitor has a first end and a second end; the first end of the first energy storage capacitor is connected to the positive electrode of the first battery cell and the first end of the first switching device, and the second end of the first energy storage capacitor is connected to the negative electrode of the second battery cell and the second end of the second switching device. The energy storage inductor has a first end and a second end; the first end of the energy storage inductor is connected to the negative electrode of the first battery cell and the positive electrode of the second battery cell, and the second end of the energy storage inductor is connected to the second end of the first switching device and the first end of the second switching device.

[0010] In some embodiments of the present disclosure, the second bidirectional balancing circuit further includes: a second energy storage capacitor. The second energy storage capacitor has a first end and a second end; the first end of the second energy storage capacitor is connected to the second end of the energy storage inductor corresponding to the first battery module of any two adjacent battery modules and the first end of the second switching device corresponding to the first battery module; the second end of the second energy storage capacitor is connected to the second end of the energy storage inductor corresponding to the second battery module of any two adjacent battery modules and the second end of the first switching device corresponding to the second battery module.

[0011] In some embodiments of the present disclosure, the first terminal of the first switching device and the first terminal of the second switching device are both drains of the corresponding switching devices, and the second terminal of the first switching device and the second terminal of the second switching device are both sources of the corresponding switching devices.

[0012] In some embodiments of the present disclosure, each of the first and second switching devices further comprises a control terminal. The energy storage battery balancing circuit further comprises a control module. The control module is connected to the control terminals of each of the first and second switching devices and is configured to output a first control signal to each of the first switching devices and a second control signal to each of the second switching devices to control the on and off states of the corresponding switching devices, respectively; the first and second control signals are complementary control signals.

[0013] Some embodiments of the present disclosure further provide an energy storage battery equalizer, comprising the energy storage battery equalization circuit as described in any of the above embodiments.

[0014] Some embodiments of the present disclosure also provide an energy storage battery balancing method, applied to a plurality of first battery cells and a plurality of second battery cells alternately connected in series, wherein each first battery cell and the second battery cell connected in series with it constitute a battery module. The energy storage battery balancing method includes: controlling a first bidirectional balancing circuit to balance the voltage of a first battery cell and the voltage of a second battery cell within a battery module; and controlling a second bidirectional balancing circuit to balance the voltage of a second battery cell within a first battery module of any two adjacent battery modules and the voltage of a first battery cell within a second battery module of the same two adjacent battery modules.

[0015] In some embodiments of the present disclosure, the first bidirectional balancing circuit and the second bidirectional balancing circuit share a first switching device connected to the corresponding first battery unit and a second switching device connected to the corresponding second battery unit to synchronously perform voltage balancing.

[0016] In some embodiments of the present disclosure, controlling the first bidirectional balancing circuit and the second bidirectional balancing circuit to perform voltage balancing includes: sending a first control signal to each first switching device and outputting a second control signal to each second switching device to respectively control the on and off of the corresponding switching device; wherein the first control signal and the second control signal are complementary control signals.

[0017] In the aforementioned energy storage battery balancing circuit, method, and energy storage battery equalizer, a first bidirectional balancing circuit and a second bidirectional balancing circuit are provided for each battery module. The first bidirectional balancing circuit can be used to balance the voltage of the first battery cell and the voltage of the second battery cell within the same battery module, while the second bidirectional balancing circuit can be used to balance the voltage of the second battery cell within the first of any two adjacent battery modules and the voltage of the first battery cell within the second of the same two adjacent battery modules. This ensures that the voltages of the battery cells converge more quickly and effectively, eliminating voltage differences between different battery cells and easily improving balancing speed, balancing efficiency, and battery energy utilization.

[0018] Furthermore, in some embodiments, the first bidirectional balancing circuit and the second bidirectional balancing circuit can share a first switching device connected to the corresponding first battery cell and a second switching device connected to the corresponding second battery cell for voltage balancing; that is, the first bidirectional balancing circuit and the second bidirectional balancing circuit can share a switching device. This effectively reduces the number of components used in the energy storage battery balancing circuit and helps reduce energy transfer losses between battery cells, thereby reducing costs and circuit size, thereby achieving miniaturization and modular expansion of the energy storage battery balancing circuit and energy storage battery equalizer.

[0019] In some embodiments, a first control signal is sent to each first switching device, and a second control signal is output to each second switching device, so that the first bidirectional balancing circuit and the second bidirectional balancing circuit can balance the voltages of the battery cells. This facilitates control of the first and second bidirectional balancing circuits, thereby reducing the occurrence of control errors. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the technical solutions in the embodiments of the present application or related technologies, the following briefly introduces the drawings required for use in the embodiments or related technical descriptions. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0021] FIG1 is a structural block diagram of an energy storage battery balancing circuit according to an embodiment;

[0022] FIG2 is a second structural block diagram of an energy storage battery balancing circuit according to an embodiment;

[0023] FIG3 is a circuit diagram of an energy storage battery balancing circuit according to an embodiment;

[0024] FIG4 is a voltage-current characteristic diagram of an energy storage battery balancing circuit according to an embodiment;

[0025] FIG5 is a diagram illustrating a first balancing mode of an energy storage battery balancing circuit according to an embodiment;

[0026] FIG6 is a schematic diagram of an equalization circuit of the first bidirectional equalization circuit in the equalization mode shown in FIG5 ;

[0027] FIG7 is a schematic diagram of an equalization circuit of a second bidirectional equalization circuit in the equalization mode shown in FIG5 ;

[0028] FIG8 is a diagram illustrating a second balancing mode of an energy storage battery balancing circuit according to an embodiment;

[0029] FIG9 is a schematic diagram of an equalization circuit of the first bidirectional equalization circuit in equalization mode 2 shown in FIG8 ;

[0030] FIG10 is a schematic diagram of an equalization circuit of the second bidirectional equalization circuit in the equalization mode 2 shown in FIG8 ;

[0031] FIG11 is a flow chart of a method for balancing energy storage batteries according to an embodiment. DETAILED DESCRIPTION

[0032] To facilitate understanding of the present application, the present application will be described more fully below with reference to the accompanying drawings. The accompanying drawings provide embodiments of the present application. However, the present application may be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to make the disclosure of the present application more thorough and comprehensive.

[0033] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which this application pertains. The terms used herein in the specification of this application are for the purpose of describing specific embodiments only and are not intended to limit this application.

[0034] It is understood that the terms "first," "second," and the like used herein may be used to describe various elements herein, but these elements are not limited by these terms. These terms are used solely to distinguish a first element from another element. For example, a first switching device may be referred to as a second switching device, and similarly, a second switching device may be referred to as a first switching device, without departing from the scope of this application. The first switching device and the second switching device are both switching devices, but they are not the same switching device.

[0035] It can be understood that the “connection” in the following embodiments should be understood as “electrical connection”, “communication connection”, etc. if there is transmission of electrical signals or data between the connected circuits, modules, units, etc.

[0036] It is understood that “at least one” refers to one or more, “a plurality” refers to two or more, and “at least a portion of an element” refers to a portion or all of an element.

[0037] As used herein, the singular forms "a," "an," and "the" may also include the plural forms, unless the context clearly indicates otherwise. It should also be understood that the terms "include," "comprising," "having," and the like specify the presence of stated features, integers, steps, operations, components, parts, or combinations thereof, but do not preclude the presence or addition of one or more other features, integers, steps, operations, components, parts, or combinations thereof. Furthermore, the term "and / or" as used in this specification includes any and all combinations of the relevant listed items.

[0038] FIG1 and FIG2 are structural block diagrams of an energy storage battery balancing circuit according to an embodiment. Referring to FIG1 and FIG2 , the energy storage battery balancing circuit according to this embodiment is applied to a plurality of first battery cells 110 and a plurality of second battery cells 120 alternately connected in series, wherein each first battery cell 110 and the second battery cell 120 connected in series therewith constitute a battery module 100.

[0039] For example, the first battery cell 110 and the second battery cell 120 are battery cells with the same structure.

[0040] For example, the negative electrode of the first battery cell 110 is connected to the positive electrode of the second battery cell 120, and the negative electrode of the second battery cell 120 is connected to the positive electrode of the first battery cell 110 in the adjacent battery module 100. In this way, the positive electrode of the first battery cell 110 is the positive electrode of the corresponding battery module 100, and the negative electrode of the second battery cell 120 is the negative electrode of the corresponding battery module 100.

[0041] For example, the energy storage battery balancing circuit includes: multiple first bidirectional balancing circuits 200 and multiple second bidirectional balancing circuits 300. The first bidirectional balancing circuits 200 are connected to the battery modules 100 and are configured to balance the voltage of the first battery cell 110 and the voltage of the second battery cell 120 in the battery module 100. The second bidirectional balancing circuits 300 are connected to any two adjacent battery modules 100 and are configured to balance the voltage of the second battery cell 120 in the first of the two adjacent battery modules 100 and the voltage of the first battery cell 110 in the second of the two adjacent battery modules 100.

[0042] In the above-described energy storage battery balancing circuit, a first bidirectional balancing circuit 200 and a second bidirectional balancing circuit 300 are provided for each battery module 100. The first bidirectional balancing circuit 200 can be used to balance the voltage of the first battery cell 110 and the voltage of the second battery cell 120 within the same battery module 100, while the second bidirectional balancing circuit 300 can be used to balance the voltage of the second battery cell 120 within the first of any two adjacent battery modules 100 and the voltage of the first battery cell 110 within the second of any two adjacent battery modules 100. In this way, the energy storage battery balancing circuit can more quickly and effectively ensure that the voltages of the various battery cells converge, thereby eliminating voltage differences between different battery cells and easily improving balancing speed, balancing efficiency, and battery energy utilization.

[0043] In some embodiments, as shown in FIG2 , the energy storage battery balancing circuit further includes: a first switching device 410 connected to each first battery cell 110, and a second switching device 420 connected to each second battery cell 120. The first bidirectional balancing circuit 200 and the second bidirectional balancing circuit 300 share the first switching device 410 connected to the first battery cell 110, and share the second switching device 420 connected to the second battery cell 120.

[0044] In the aforementioned energy storage battery balancing circuit, the first bidirectional balancing circuit 200 and the second bidirectional balancing circuit 300 can share the first switching device 410 connected to the corresponding first battery cell 110 and the second switching device 420 connected to the corresponding second battery cell 420 for voltage balancing; that is, the first bidirectional balancing circuit 200 and the second bidirectional balancing circuit 300 can share switching devices. This effectively reduces the number of components used in the energy storage battery balancing circuit (for example, the number of switching devices and the number of energy storage inductors), and also helps reduce energy transfer losses between battery cells, thereby reducing costs and circuit size, thereby achieving miniaturization and modular expansion of the energy storage battery balancing circuit and energy storage battery balancer.

[0045] It should be noted that "voltage balancing" in any embodiment of the present disclosure refers to aligning the voltages of two corresponding battery cells, for example, ensuring that the voltage difference between the two corresponding battery cells is within a preset range. Optionally, the preset range may be such that, after voltage balancing, the voltage difference between the two corresponding battery cells is within a range of 0mV-50mV.

[0046] It is understood that the first bidirectional balancing circuit 200 and the second bidirectional balancing circuit 300 can be implemented using a variety of different bidirectional balancing circuits, such as those based on DC / DC converters, such as bidirectional Buck-Boost balancing circuits or bidirectional Cuk converter circuits, thereby achieving voltage balancing between battery cells while simultaneously transferring power between battery packs (PACKs) to improve balancing efficiency. A battery pack (PACK) can be composed of multiple battery modules 100 connected in series and parallel.

[0047] The following embodiments of the present disclosure exemplarily provide some possible implementations of the first bidirectional equalizing circuit 200 and the second bidirectional equalizing circuit 300 , but are not limited thereto.

[0048] In some embodiments, as shown in FIG2 , the first switching device 410 and the second switching device 420 each have a first end and a second end. The first bidirectional balancing circuit 200 further includes: a first energy storage capacitor 210 and an energy storage inductor 220. The first energy storage capacitor 210 has a first end and a second end; the first end of the first energy storage capacitor 210 is connected to the positive electrode of the first battery cell 110 and the first end of the first switching device 410, and the second end of the first energy storage capacitor 210 is connected to the negative electrode of the second battery cell 120 and the second end of the second switching device 420. The energy storage inductor 220 has a first end and a second end; the first end of the energy storage inductor 220 is connected to the negative electrode of the first battery cell 110 and the positive electrode of the second battery cell 120, and the second end of the energy storage inductor 220 is connected to the second end of the first switching device 410 and the first end of the second switching device 420.

[0049] In some embodiments, as shown in FIG2 , the second bidirectional balancing circuit 300 further includes: a second energy storage capacitor 310. The second energy storage capacitor 310 has a first end and a second end; the first end of the second energy storage capacitor 310 is connected to the second end of the energy storage inductor 220 corresponding to the first battery module 100 of any two adjacent battery modules 100 and the first end of the second switch device 420 corresponding to the first battery module 100; the second end of the second energy storage capacitor 310 is connected to the second end of the energy storage inductor 220 corresponding to the second battery module 100 of any two adjacent battery modules 100 and the second end of the first switch device 410 corresponding to the second battery module 100.

[0050] In some embodiments, the first terminal of the first switching device 410 and the first terminal of the second switching device 420 are both drains of the corresponding switching devices, and the second terminals of the first switching device 410 and the second terminals of the second switching device 420 are both sources of the corresponding switching devices.

[0051] In some embodiments, the number of the second bidirectional balancing circuits 300 is equal to the number of the first bidirectional balancing circuits 200 minus one.

[0052] To more clearly illustrate the energy storage battery balancing circuit provided by some embodiments of the present disclosure, FIG3 illustrates an example in which the first battery cell 110 and the second battery cell 120 are the same battery cells, and the first switching device 410 and the second switching device 420 are the same switching devices.

[0053] Please refer to FIG3 , the energy storage battery consists of n battery cells (e.g. B1, B2, B3, ..., B n ) are connected in series in sequence, where n is an even number and is greater than or equal to 4; the battery cells corresponding to the odd numbers (e.g. B1, B3, ..., B n-1 ) is the first battery cell 110, and the battery cells corresponding to the even numbers (such as B2, B4, ..., Bn ) is the second battery cell 120. Moreover, the positive electrode of the first battery cell serves as the positive electrode of the entire energy storage battery, and the negative electrode of the nth battery cell serves as the negative electrode of the entire energy storage battery. The first switching device 410 and the second switching device 420 can be sequentially identified as S1, S2, S3, ..., S according to the series connection order of their corresponding battery cells. n , where the odd-numbered switching devices (e.g. S1, S3, ..., S n-1 ) is the first switch device 410, and the switch devices corresponding to the even numbers (such as S2, S4, ..., S n ) is the second switching device 420.

[0054] Accordingly, referring to FIG3 , the number of the first bidirectional balancing circuits 200 is n / 2, and the number of the second bidirectional balancing circuits 300 is (n-2) / 2. In the j / 2th (j=2, 4, 6, ..., n) first bidirectional balancing circuit, the battery cell B j-1 The positive electrode and the switching device S j-1 The first end (eg, drain) of the first energy storage capacitor C1 j / 2 The first end of the battery cell B is connected to the first terminal of the first bidirectional balancing circuit 200; j-1 The negative electrode of battery cell B j The positive electrode, energy storage inductor L j / 2 The first end of the energy storage inductor L j / 2 The second end of the switching device S j-1 The second end (eg, source) of the switching device S j The first end (eg, drain) of the battery cell B is connected to the first end (eg, drain) of the battery cell B, which can serve as the second terminal of the first bidirectional balancing circuit 200; j The negative electrode and the switching device S j The second end (eg, source) of the first energy storage capacitor C1 j / 2 The second end of the first bidirectional equalizing circuit 200 is connected to the second end of the first bidirectional equalizing circuit 200, which can serve as the third terminal of the first bidirectional equalizing circuit 200. Moreover, when j≠2, the first terminal of the j / 2th first bidirectional equalizing circuit 200 is connected to the third terminal of the (j / 2)-1th first bidirectional equalizing circuit 200.

[0055] 3 , the [(k-2) / 2]th (k=j, k≥4) second bidirectional balancing circuit 300 is a circuit derived from the j / 2th first bidirectional balancing circuit 200. That is, the [(k-2) / 2]th (k=j, k≥4) second bidirectional balancing circuit 300 and the j / 2th first bidirectional balancing circuit 200 share a common circuit. For example, the common circuit may be represented by the following connections: j The negative electrode of the battery cell B in the adjacent battery module 100j+1 The positive electrode, switching device S j The second end (eg, source) of the battery cell B in the adjacent battery module 100 j+1 Corresponding switching device S j+1 The first end (eg, drain) of the battery cell B is connected; j The positive electrode and the energy storage inductor L j / 2 The first end of the energy storage inductor L j / 2 The second end of the switching device S j The first end (eg, drain) of the adjacent battery module 100 is connected to the second terminal of the j / 2 first bidirectional balancing circuit 200; the battery cell B in the adjacent battery module 100 j+1 The negative pole and the corresponding energy storage inductor L (j / 2)+1 The first end of the energy storage inductor L (j / 2)+1 The second end of the corresponding switch device S j+1 The second end (eg, source) of the first bidirectional equalizing circuit 200 is connected to the second terminal (eg, source) of the first bidirectional equalizing circuit 200 (j / 2)+1). On this basis, the second terminal of the first bidirectional equalizing circuit 200 is connected to the second energy storage capacitor C2. j / 2 The first end of the (j / 2)+1th first bidirectional balancing circuit 200 is connected to the second energy storage capacitor C2 j / 2 The second end of is connected to each other, and thus a [(k-2) / 2]th (k=j, k≥4) second bidirectional balancing circuit 300 can be obtained.

[0056] It is worth mentioning that, in some embodiments of the present disclosure, please continue to refer to FIG. 3 , each first switch device 410 (eg, S1, S3, . . . , S n-1 ) and each second switching device 420 (eg, S2, S4, ..., S n ) also have a control terminal (e.g., a gate). The energy storage battery balancing circuit further includes a control module (not shown in FIG3 ). The control module is connected to the control terminals of each first switching device 410 and each second switching device 420 and is configured to output a first control signal to each first switching device 410 and a second control signal to each second switching device 420 to control the on and off of the corresponding switching device, respectively. The first control signal and the second control signal are complementary control signals.

[0057] In some embodiments, the first control signal and the second control signal are both pulse width modulation (PWM) control signals, and the control waveforms of the first control signal and the second control signal are complementary.

[0058] In some embodiments, the control module can be, for example, a device for outputting level signals (such as an external power supply, etc.), which can control the on and off of each switching device by outputting a high level signal or a low level signal to the control end (such as the gate) of each switching device.

[0059] As described above, when the cell voltages of any one or more battery cells connected in series within the energy storage battery are inconsistent, the energy storage battery balancing circuit provided in the disclosed embodiment can achieve energy transfer between the battery cells by controlling each first switch device 410 and each second switch device 420 (i.e., all switch devices). Furthermore, in the disclosed embodiment, the control method for each switch device is simple: the first switch devices 410 corresponding to odd numbers are controlled by the same first control signal, and the second switch devices 420 corresponding to even numbers are controlled by the same second control signal. This effectively reduces the occurrence of control errors.

[0060] For example, referring to FIG. 4 , under the action of the first control signal, when each first switch device 410 is turned on (eg, S1, S3, . . . , S n-1 )'s gate-source drive voltages are uGS1, uGS3, ..., uGS n-1 Under the action of the second control signal, each second switch device 420 (eg S2, S4, ..., S n ) are turned on, the gate-source drive voltages are uGS2, uGS4, ..., uGS n Correspondingly, each energy storage inductor L in the energy storage battery balancing circuit j / 2 The voltage uL across (j=2, 4, 6, ..., n) j / 2 and current iL j / 2 The waveform can be shown in Figure 4. Moreover, within a balancing cycle T of the energy storage battery balancing circuit (the balancing cycle T includes a first stage T1 and a second stage T2), the topological operating mode diagrams of the energy storage battery balancing circuit are shown in Figures 5 and 8, respectively. Figure 5 is a schematic diagram of the operating mode 1 of the energy storage battery balancing circuit in the first stage T1, and Figure 8 is a schematic diagram of the operating mode 2 of the energy storage battery balancing circuit in the second stage T2. The various loops formed by the energy storage battery balancing circuit in operating modes 1 and 2 and their corresponding current flows can be seen in the figures.

[0061] 5, 6 and 7, in the first stage T1, each first switch device 410 (eg, S1, S3, ..., S n-1 ) are turned on at the same time, and each second switch device 420 (such as S2, S4, ..., S n) are turned off at the same time. Battery unit B1, switch device S1 and energy storage inductor L1 form a loop in sequence, battery unit B3, switch device S3 and energy storage inductor L2 form a loop in sequence, ..., battery unit B j-1 , switching device S j-1 and energy storage inductor L j / 2 The circuits are formed in sequence so that the battery cells B in each circuit j-1 Give the energy storage inductor L j / 2 At the same time, the battery cell B2, the energy storage inductor L1, the switch device S1 and the first energy storage capacitor C11 sequentially form a loop ①, the battery cell B4, the energy storage inductor L2, the switch device S3 and the first energy storage capacitor C12 sequentially form a loop ①, ..., the battery cell B j , energy storage inductor L j / 2 , switching device S j-1 and the first energy storage capacitor C1 j / 2 Forming loop ①, so that the energy stored in the first energy storage capacitor C1 j / 2 The energy in the circuit can be transferred to the energy storage inductor L through the circuit ①. j / 2 and battery cell B j At the same time, the battery cell B2, the energy storage inductor L1, the second energy storage capacitor C21 and the switch device S3 sequentially form a loop ②, the battery cell B4, the energy storage inductor L2, the second energy storage capacitor C22 and the switch device S5 sequentially form a loop ②, ..., the battery cell B k-2 , energy storage inductor L (k / 2)-1 , the second energy storage capacitor C2 (k-2) / 2 and switching device S k-1 The circuit ② is formed in sequence so that the energy stored in the second energy storage capacitor C2 (k-2) / 2 The energy in the circuit can be transferred to the energy storage inductor L through the circuit ②. (k / 2)-1 and battery cell B k-2 Charging is performed (k=j and k≥4).

[0062] 8, 9 and 10, in the second phase T2, each first switch device 410 (eg, S1, S3, ..., S n-1 ) are turned off at the same time, and each second switch device 420 (such as S2, S4, ..., S n ) are turned on at the same time. Battery cell B2, energy storage inductor L1 and switch device S2 form a loop in sequence, battery cell B4, energy storage inductor L2 and switch device S2 form a loop in sequence, ..., battery cell B j , energy storage inductor L j / 2 and switching device S j The circuit is formed in sequence so that the energy stored in the energy storage inductor L j / 2 The energy in the battery is fed to the battery unit B through each circuit jAt the same time, the battery unit B1, the first energy storage capacitor C11, the switch device S2 and the energy storage inductor L1 sequentially form a loop ①, the battery unit B3, the first energy storage capacitor C12, the switch device S4 and the energy storage inductor L2 sequentially form a loop ①, ..., the battery unit B j-1 , the first energy storage capacitor C1 j / 2 , switching device S j and energy storage inductor L j / 2 Forming loop ①, so that the energy stored in the energy storage inductor L j / 2 Energy in battery cell B j-1 Together through loop ① to the first energy storage capacitor C1 j / 2 At the same time, the battery cell B3, the switch device S2, the second energy storage capacitor C21 and the energy storage inductor L2 sequentially form a loop ②, the battery cell B5, the switch device S4, the second energy storage capacitor C22 and the energy storage inductor L3 sequentially form a loop ②, ..., the battery cell B k-1 , switching device S k-2 , the second energy storage capacitor C2 (k-2) / 2 and energy storage inductor L k / 2 The circuit ② is formed in sequence so that the energy stored in the energy storage inductor L k / 2 Energy in battery cell B k-1 Together through loop ② to the second energy storage capacitor C2 (k-2) / 2 Charging is performed (k=j and k≥4).

[0063] In summary, the energy storage battery balancing circuit provided by the embodiment of the present disclosure can greatly improve its overall balancing efficiency, and can also effectively realize the transfer of power between battery packs when a small number of battery cells are connected in series within the battery pack. The embodiment of the present disclosure uses a first bidirectional balancing circuit and a second bidirectional balancing circuit in the energy storage battery balancing circuit to transfer the charge and discharge energy of the energy storage battery. The structure is clear and compact, easy to implement modular expansion, and can effectively reduce the loss of energy transfer between battery cells or between battery packs, thereby improving the utilization rate of battery energy and achieving more charge and discharge cycles, ensuring that the energy storage battery can have a longer service life and providing users with a better experience.

[0064] Some embodiments of the present disclosure further provide an energy storage battery equalizer, including the energy storage battery equalization circuit described in any of the above embodiments. The energy storage battery equalizer of this embodiment can more quickly and effectively ensure that the voltages of each battery cell converge to a uniform level, thereby eliminating voltage differences between different battery cells. It can also easily improve the balancing speed, balancing efficiency, and battery energy utilization, effectively reduce the number of components used in the energy storage battery equalization circuit, and help reduce energy transfer losses between battery cells, thereby reducing costs and reducing circuit size, thereby achieving miniaturization and modular expansion of the energy storage battery equalization circuit and energy storage battery equalizer.

[0065] Some embodiments of the present disclosure also provide an energy storage battery balancing method, which can be implemented using the energy storage battery balancing circuit and energy storage battery equalizer described in any of the above embodiments. This energy storage battery balancing method can be applied to the aforementioned plurality of first battery cells and plurality of second battery cells alternately connected in series, where each first battery cell and the second battery cell connected in series together constitute a battery module. Referring to FIG. 11 , this energy storage battery balancing method includes the following steps S10 and S20.

[0066] S10 , controlling a first bidirectional balancing circuit to balance the voltage of a first battery cell and the voltage of a second battery cell in a battery module.

[0067] S20 , controlling the second bidirectional balancing circuit to balance the voltage of the second battery cell in the first battery module of any two adjacent battery modules and the voltage of the first battery cell in the second battery module of any two adjacent battery modules.

[0068] For example, the first bidirectional balancing circuit and the second bidirectional balancing circuit share a first switching device connected to the first battery unit and a second switching device connected to the second battery unit to synchronously perform voltage balancing.

[0069] For example, controlling the first bidirectional balancing circuit and the second bidirectional balancing circuit to perform voltage balancing in steps S10 and S20 includes: sending a first control signal to each first switching device and outputting a second control signal to each second switching device to respectively control the on and off of the corresponding switching device; wherein the first control signal and the second control signal are complementary control signals.

[0070] For example, the first control signal and the second control signal can be generated and output by the control module in the aforementioned embodiment. Furthermore, the relevant features of the battery module, control module, first bidirectional balancing circuit, second bidirectional balancing circuit, etc. can be referred to the relevant descriptions of the aforementioned embodiments and will not be repeated here.

[0071] It should be understood that, although the various steps in the flow chart of the above-described embodiment are shown in sequence according to the indication of the arrows, these steps are not necessarily performed in sequence according to the order indicated by the arrows. Unless clearly stated herein, the execution of these steps is not strictly limited in order, and these steps can be performed in other orders. Moreover, at least a portion of the steps in the flow chart of the above-described embodiment may include a plurality of sub-steps or a plurality of stages, and these sub-steps or stages are not necessarily performed at the same time, but can be performed at different times, and the execution order of these sub-steps or stages is not necessarily performed in sequence, but can be performed in turn or alternately with at least a portion of other steps or sub-steps or stages of other steps.

[0072] In the description of this specification, reference to the terms "some embodiments" or "other embodiments" means that the specific features, structures, materials, or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic descriptions of the above terms do not necessarily refer to the same embodiment or example.

[0073] The technical features of the above embodiments can be combined arbitrarily. In order to make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0074] The above embodiments merely illustrate several embodiments of the present application. While the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the present application. It should be noted that a person of ordinary skill in the art may make various modifications and improvements without departing from the spirit of the present application, all of which fall within the scope of protection of the present application. Therefore, the scope of protection of the present application shall be determined by the appended claims.

Claims

1. An energy storage battery balancing circuit, applied to a plurality of first battery cells and a plurality of second battery cells alternately connected in series, wherein each of the first battery cells and the second battery cells connected in series therewith constitute a battery module; The energy storage battery balancing circuit comprises: A plurality of first bidirectional balancing circuits; the first bidirectional balancing circuits are connected to the battery modules correspondingly and are configured to: balance the voltage of the first battery cell and the voltage of the second battery cell in the battery module; A plurality of second bidirectional balancing circuits; the second bidirectional balancing circuits are correspondingly connected to any two adjacent battery modules and are configured to balance the voltage of the second battery cell in the first battery module of the any two adjacent battery modules and the voltage of the first battery cell in the second battery module of the any two adjacent battery modules.

2. The energy storage battery equalization circuit according to claim 1, further comprising: a first switching device connected to each of the first battery cells, and a second switching device connected to each of the second battery cells; The first bidirectional balancing circuit and the second bidirectional balancing circuit share the first switching device connected to the first battery unit, and share the second switching device connected to the second battery unit.

3. The energy storage battery equalization circuit according to claim 2, wherein: The negative electrode of the first battery cell is connected to the positive electrode of the second battery cell, and the negative electrode of the second battery cell is connected to the positive electrode of the first battery cell in the adjacent battery module; the first switching device and the second switching device both have a first end and a second end; wherein, The first bidirectional equalization circuit further includes: A first energy storage capacitor having a first end and a second end; the first end of the first energy storage capacitor is connected to the positive electrode of the first battery unit and the first end of the first switch device, and the second end of the first energy storage capacitor is connected to the negative electrode of the second battery unit and the second end of the second switch device; An energy storage inductor has a first end and a second end; the first end of the energy storage inductor is connected to the negative electrode of the first battery unit and the positive electrode of the second battery unit, and the second end of the energy storage inductor is connected to the second end of the first switching device and the first end of the second switching device.

4. The energy storage battery equalization circuit according to claim 3, wherein: The second bidirectional equalization circuit further includes: A second energy storage capacitor has a first end and a second end; the first end of the second energy storage capacitor is connected to the second end of the energy storage inductor corresponding to the first battery module of any two adjacent battery modules and the first end of the second switching device corresponding to the first battery module; the second end of the second energy storage capacitor is connected to the second end of the energy storage inductor corresponding to the second battery module of any two adjacent battery modules and the second end of the first switching device corresponding to the second battery module.

5. The energy storage battery equalization circuit according to claim 3, wherein: The first end of the first switching device and the first end of the second switching device are both drains of corresponding switching devices; the second end of the first switching device and the second end of the second switching device are both sources of corresponding switching devices.

6. The energy storage battery equalization circuit according to any one of claims 2 to 5, wherein: The first switch device and the second switch device both have a control terminal; the energy storage battery balancing circuit also includes: a control module connected to the control terminals of the first switching devices and the second switching devices, and configured to: output a first control signal to each of the first switching devices, and output a second control signal to each of the second switching devices, so as to respectively control the on and off of the corresponding switching devices; The first control signal and the second control signal are complementary control signals.

7. The energy storage battery equalization circuit according to any one of claims 1 to 5, wherein: The number of the second bidirectional equalizing circuits is equal to the number of the first bidirectional equalizing circuits minus one.

8. The energy storage battery equalization circuit according to any one of claims 1 to 5, wherein: The first battery cell and the second battery cell are composed of n battery cells, wherein n is an even number and is greater than or equal to 4, the battery cell corresponding to the odd number is the first battery cell, and the battery cell corresponding to the even number is the second battery cell, the number of the first bidirectional balancing circuits is n / 2, and the number of the second bidirectional balancing circuits is (n-2) / 2.

9. The energy storage battery equalization circuit according to claim 6, wherein: The control end is a gate.

10. The energy storage battery equalization circuit according to claim 6, wherein: The first control signal and the second control signal are both pulse width modulation control signals, and the control waveforms of the first control signal and the second control signal are complementary.

11. An energy storage battery equalizer, comprising the energy storage battery equalization circuit according to any one of claims 1 to 10.

12. A method for balancing an energy storage battery, applied to a plurality of first battery cells and a plurality of second battery cells alternately connected in series, wherein each of the first battery cells and the second battery cells connected in series therewith constitute a battery module; The energy storage battery balancing method comprises: Controlling a first bidirectional balancing circuit to balance the voltage of the first battery cell and the voltage of the second battery cell in the battery module; The second bidirectional balancing circuit is controlled to balance the voltage of the second battery cell in the first battery module of any two adjacent battery modules and the voltage of the first battery cell in the second battery module of any two adjacent battery modules.

13. The energy storage battery balancing method according to claim 12, wherein: The first bidirectional balancing circuit and the second bidirectional balancing circuit share a first switch device connected to the first battery unit and a second switch device connected to the second battery unit to synchronously perform voltage balancing.

14. The energy storage battery balancing method according to claim 13, wherein: Controlling the first bidirectional balancing circuit and the second bidirectional balancing circuit to perform voltage balancing, including: sending a first control signal to each of the first switching devices, and outputting a second control signal to each of the second switching devices, so as to respectively control the conduction and disconnection of the corresponding switching devices; The first control signal and the second control signal are complementary control signals.

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