Equalization circuit and energy storage battery equalization method

Abstract

The invention relates to an equalization circuit and an energy storage battery equalization method. The equalization circuit comprises a plurality of first equalization circuits and a plurality of second equalization circuits which are in one-to-one correspondence with a plurality of battery modules in the battery; wherein the plurality of battery modules are mutually connected in series, and each battery module comprises a plurality of battery cells which are mutually connected in series; the first equalization circuit is connected with the battery cell in the corresponding battery module and is used for equalizing the voltage of the battery cell in the corresponding battery module; and each second equalization circuit is connected with two adjacent battery modules and is used for equalizing the voltage of the two connected battery modules. The equalization circuit can equalize the voltage of each battery cell in the battery pack.

Description

Technical Field

[0001] The present application relates to the field of battery technology, and in particular to an equalization circuit and an energy storage battery equalization method. Background Art

[0002] In recent years, with the vigorous development of the new energy industry, batteries such as lithium iron phosphate batteries have been widely used in the energy storage field, but the voltage and capacity of a single battery cell cannot fully meet the actual needs. In order to obtain higher voltage and larger capacity, multiple battery cells must be connected in series to form a battery pack before they can be put into use.

[0003] However, due to the differences between each battery cell, some battery cells may be overcharged or over-discharged when used in series, which will not only significantly reduce the service life of the battery, but may even cause safety hazards.

[0004] Therefore, in order to solve the inconsistency problem between battery cells, voltage balancing function becomes one of the indispensable functions of series battery packs. Summary of the invention

[0005] Based on this, it is necessary to provide a balancing circuit and a storage battery balancing method that can balance the voltages of each battery cell in a battery pack in order to address the above technical problems.

[0006] In a first aspect, the present application provides a balancing circuit. The balancing circuit comprises:

[0007] A plurality of first balancing circuits corresponding to a plurality of battery modules in the battery; wherein the plurality of battery modules are connected in series, and each battery module comprises a plurality of battery cells connected in series; the first balancing circuits are connected to the battery cells in the corresponding battery modules, and are used to balance the voltages of the battery cells in the corresponding battery modules;

[0008] A plurality of second balancing circuits; each second balancing circuit is connected to two adjacent battery modules and is used for balancing the voltages of the two connected battery modules.

[0009] In one embodiment, the first balancing circuit includes a first coupled inductor and a plurality of first transmission branches connected one-to-one with each battery cell in the battery module; the first coupled inductor is connected to each first transmission branch to transmit the energy of the battery cell with high voltage in the battery module to the battery cell with low voltage through each first transmission branch and the first coupled inductor.

[0010] In one embodiment, each first transmission branch includes a first balancing switch element; the first balancing switch element is turned on under the control of a first balancing signal, so that the battery cell connected to the first transmission branch where the first balancing switch element is located outputs its own energy to the first coupled inductor through the first transmission branch or receives energy transmitted by the first coupled inductor.

[0011] In one embodiment, the battery module includes a first battery cell, a second battery cell, a third battery cell and a fourth battery cell; the multiple first transmission branches include a first energy transmission branch, a second energy transmission branch, a third energy transmission branch and a fourth energy transmission branch; the first energy transmission branch includes a first switch element and is connected to the first battery cell; the second energy transmission branch includes a second switch element and is connected to the second battery cell; the third energy transmission branch includes a third switch element and is connected to the third battery cell; the fourth energy transmission branch includes a fourth switch element and is connected to the fourth battery cell.

[0012] In one embodiment, the first switch element, the second switch element, the third switch element and the fourth switch element are switch tubes and the gates are controlled by the first balanced signal; the positive electrode of the first battery cell is connected to the drain electrode of the first switch element; the source electrode of the first switch element is connected to the primary same-name terminal of the first coupled inductor and the drain electrode of the second switch element; the primary opposite-name terminal of the first coupled inductor is connected to the negative electrode of the first battery cell and the positive electrode of the second battery cell; the negative electrode of the second battery cell is connected to the source electrode of the second switch element; the secondary same-name terminal of the first coupled inductor is connected to the source electrode of the third switch element and the drain electrode of the fourth switch element; the drain electrode of the third switch element is connected to the positive electrode of the third battery cell; the negative electrode of the third battery cell is connected to the positive electrode of the fourth battery cell and the secondary opposite-name terminal of the first coupled inductor; the source electrode of the fourth switch element is connected to the negative electrode of the fourth battery cell.

[0013] In one embodiment, the first equalization signal includes a first control signal and a second control signal with opposite level values; the first switch element and the third switch element are controlled by the first control signal, and the second switch element and the fourth switch element are controlled by the second control signal.

[0014] In one embodiment, when the voltages of the first battery cell, the second battery cell, the third battery cell and the fourth battery cell decrease sequentially, when the first switch element and the third switch element are turned on under the control of the first control signal and the second switch element and the fourth switch element are turned off under the control of the second control signal, voltage balance is achieved between the first battery cell and the third battery cell; and the first coupled inductor stores energy; when the first switch element and the third switch element are turned off under the control of the first control signal and the second switch element and the fourth switch element are turned on under the control of the second control signal, the energy of the first coupled inductor is transmitted to the second battery cell and the fourth battery cell to balance the voltages of the second battery cell and the fourth battery cell.

[0015] In one embodiment, the second balancing circuit includes a second coupled inductor and two second transmission branches corresponding to two battery modules connected to the second balancing circuit; the second coupled inductor is connected to each second transmission branch to transmit the energy of the battery cells in the battery module with a higher voltage among the two adjacent battery modules to the battery cells in the battery module with a lower voltage among the two adjacent battery modules through each second transmission branch and the second coupled inductor.

[0016] In one embodiment, the two second transmission branches include a first cross-module transmission branch and a second cross-module transmission branch; two adjacent battery modules include a first battery module and a second battery module; the first cross-module transmission branch is connected to the first target battery cell in the first battery module, and the second cross-module transmission branch is connected to the second target battery cell in the second battery module; wherein the first target battery cell and the second target battery cell are connected in series with each other, and the negative pole of the first target battery cell is connected to the positive pole of the second target battery cell.

[0017] In one embodiment, the first cross-module transmission branch includes a fifth switch element and is connected to the first target battery cell, and the second cross-module transmission branch includes a sixth switch element and is connected to the second target battery cell; when the fifth switch element is turned on under the control of the second balanced signal, the first target battery cell outputs its own energy to the second coupled inductor through the first cross-module transmission branch or receives energy transmitted by the second coupled inductor; when the sixth switch element is turned on under the control of the second balanced signal, the second target battery cell outputs its own energy to the second coupled inductor through the second cross-module transmission branch or receives energy transmitted by the second coupled inductor.

[0018] In one embodiment, the fifth switch element and the sixth switch element are switch tubes and their gates are controlled by a second equalization signal; the drain of the fifth switch element is connected to the positive electrode of the first target battery cell; the source of the fifth switch element is connected to the first end of the second coupled inductor and the drain of the sixth switch element; the second end of the second coupled inductor is connected to the positive electrode of the second target battery cell; the source of the sixth switch element is connected to the negative electrode of the second target battery cell.

[0019] In one embodiment, the second equalization signal includes a third control signal and a fourth control signal with opposite level values; the fifth switch element is controlled by the third control signal, and the sixth switch element is controlled by the fourth control signal.

[0020] In one embodiment, when the voltage of the first target battery cell is greater than the voltage of the second target battery cell, the fifth switch element is turned on under the control of the third control signal and the sixth switch element is turned off under the control of the fourth control signal, the first target battery cell charges the second coupled inductor; when the fifth switch element is turned off under the control of the third control signal and the sixth switch element is turned on under the control of the fourth control signal, the energy stored in the second coupled inductor is transmitted to the second target battery cell to balance the voltages of the first target battery cell and the second target battery cell.

[0021] In a second aspect, the present application provides a method for balancing an energy storage battery, which is used in a controller connected to the balancing circuit as described in any one of the first aspects above, and the method includes:

[0022] When the voltages of the battery cells in the battery module are inconsistent, the first balancing circuit is controlled to balance the voltages of the battery cells in the connected battery module; wherein the first balancing circuit is connected to the battery cells in the corresponding battery module; when the voltages of two adjacent battery modules are inconsistent, the second balancing circuit is controlled to balance the voltages of the two connected battery modules; wherein the second balancing circuit is connected to the two adjacent battery modules.

[0023] The above-mentioned equalization circuit and energy storage battery equalization method, the equalization circuit includes: a plurality of first equalization circuits and a plurality of second equalization circuits corresponding to a plurality of battery modules in the battery; wherein the plurality of battery modules are connected in series, and each battery module includes a plurality of battery cells connected in series; the first equalization circuit is connected to the battery cells in the corresponding battery module, and is used to equalize the voltage of the battery cells in the corresponding battery module; each second equalization circuit is connected to two adjacent battery modules, and is used to equalize the voltage of the two connected battery modules. In this way, the first equalization circuits do not interfere with each other, and can equalize the voltage of each battery cell in each battery module. At the same time, the second equalization circuits are used to equalize the battery modules, thereby reducing energy loss and improving the equalization speed. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. 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 creative work.

[0025] Figure 1 is a schematic diagram of an equalization circuit in one embodiment;

[0026] Figure 2 is a schematic diagram of a first equalization circuit in one embodiment;

[0027] Figure 3is a schematic diagram of another first equalization circuit in one embodiment;

[0028] Figure 4 is a schematic diagram of another first equalization circuit in one embodiment;

[0029] Figure 5 is a schematic diagram of another first equalization circuit in one embodiment;

[0030] Figure 6 is a schematic diagram of a second equalizing circuit in one embodiment;

[0031] Figure 7 is a schematic diagram of another second equalizing circuit in one embodiment;

[0032] Figure 8 is a schematic diagram of another second equalizing circuit in one embodiment;

[0033] Fig. 9 is a schematic diagram of an energy storage battery pack balancing circuit in one embodiment;

[0034] Fig.10 A schematic diagram of a current waveform of a switch tube driving signal and a corresponding inductor in an embodiment;

[0035] Fig.11 A schematic diagram of another switch tube driving signal and a current waveform of a corresponding inductor in an embodiment;

[0036] Fig.12 A schematic diagram of a circuit operation mode in one embodiment;

[0037] Fig.13 A schematic diagram of another circuit operation mode in one embodiment;

[0038] Fig.14 A schematic diagram of another circuit operation mode in one embodiment;

[0039] Fig.15 A schematic diagram of another circuit operation mode in an embodiment. DETAILED DESCRIPTION

[0040] In order to make the above-mentioned purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are described in detail below in conjunction with the accompanying drawings. It should be understood that many specific details are set forth in the following description to facilitate a full understanding of the present application, but the present application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without violating the connotation of the present application, so the present application is not limited by the specific embodiments disclosed below.

[0041] 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 belongs. The terms used herein in the specification of this application are only for the purpose of describing specific embodiments and are not intended to limit this application.

[0042] In the description of the present application, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of the features. In the description of the present application, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0043] In this application, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0044] It should be noted that when an element is referred to as being "fixed to" or "disposed on" another element, it may be directly on the other element or there may be an intermediate element. When an element is considered to be "connected to" another element, it may be directly connected to the other element or there may be an intermediate element at the same time.

[0045] It is understood that the terms "first", "second", etc. used in this application may be used herein to describe various elements, but these elements are not limited by these terms. These terms are only used to distinguish a first element from another element. For example, without departing from the scope of this application, a first resistor may be referred to as a second resistor, and similarly, a second resistor may be referred to as a first resistor. Both the first resistor and the second resistor are resistors, but they are not the same resistor.

[0046] It can be understood that the “connection” in the following embodiments should be understood as “electrical connection”, “communication connection”, etc. if the connected circuits, modules, units, etc. have electrical signals or data transmission between each other.

[0047] It can be understood that “at least one” means one or more, “plurality” means two or more, and “at least a portion of an element” means a part or all of an element.

[0048] In recent years, with the vigorous development of the new energy industry, lithium iron phosphate batteries have been widely used in the field of energy storage, but the voltage and capacity of a single battery cell cannot fully meet the actual needs. In order to obtain higher voltage and larger capacity, multiple battery modules must be connected in series to form a battery pack before they can be put into use. However, due to the differences between each lithium iron phosphate battery module, some battery modules may be overcharged or over-discharged when used in series, which will not only significantly reduce the service life of the battery, but may even cause safety hazards. Therefore, in order to solve the inconsistency problem between battery modules, the voltage balancing function has become one of the indispensable functions of the series battery pack.

[0049] Currently, lithium battery equalizers can be mainly divided into two types: passive equalizers and active equalizers. Passive equalizers, also known as energy-loss equalizers, achieve equalization by converting the extra energy in the battery module into heat energy. However, this method has the problems of large energy loss and low balancing efficiency, and is not very ideal in practical applications. In contrast, active equalizers, as a non-energy-loss equalizer, transfer energy through energy storage elements, thereby reducing the inconsistency of the battery pack. However, the current typical active equalizers result in unsatisfactory balancing efficiency in large-scale lithium battery packs, and the circuit uses more components, resulting in higher costs.

[0050] In view of this, an embodiment of the present application provides a balancing circuit, which can effectively balance a battery pack while having a high balancing speed and low cost.

[0051] In one embodiment, Figure 1 As shown, a balancing circuit is provided, which comprises: a plurality of first balancing circuits 1 and a plurality of second balancing circuits 2 corresponding to a plurality of battery modules in a battery. The plurality of battery modules are connected in series, and each battery module comprises a plurality of battery cells connected in series; the first balancing circuit 1 is connected to the battery cells in the corresponding battery module, and is used to balance the voltage of the battery cells in the corresponding battery module; each second balancing circuit 2 is connected to two adjacent battery modules, and is used to balance the voltage of the two connected battery modules.

[0052] The battery refers to a battery pack, which includes a plurality of battery modules connected in series, and each battery module includes a plurality of battery cells connected in series. That is, the battery pack is obtained by connecting the battery cells in series, and each battery cell is divided into a plurality of battery modules.

[0053] The balancing circuit includes a first balancing circuit 1 and a second balancing circuit 2. The balancing circuit is connected to each battery module of the battery pack. Specifically, each battery module is connected to a corresponding first balancing circuit 1, and the first balancing circuit 1 performs voltage balancing on each battery cell when the voltage of each battery cell in the battery module is unbalanced. Optionally, the first balancing circuit 1 is connected to each battery cell in the battery module.

[0054] In addition, a second balancing circuit 2 is connected between each two adjacent battery modules. When the voltage between the two battery modules is unbalanced, the second balancing circuit 2 is used to balance the voltage of the two battery modules. Optionally, the second balancing circuit 2 is connected to one of the cells in the two adjacent battery modules. When the voltage of the two cells is unbalanced, it means that the voltage between the two battery modules is unbalanced, so the second balancing circuit 2 is used to balance the voltage of the two battery modules.

[0055] It is understandable that the number of the first balancing circuits 1 is equal to the number of the battery modules. Optionally, the number of the second balancing circuits 2 is one less than the number of the battery modules.

[0056] Optional, such as Figure 1 As shown, each battery module includes 4 battery cells.

[0057] Optionally, the first equalizing circuit 1 is a coupled half-bridge circuit, and the second equalizing circuit 2 is a buck-boost circuit.

[0058] The above-mentioned equalization circuit includes a plurality of first equalization circuits 1 and a plurality of second equalization circuits 2 corresponding to a plurality of battery modules in the battery; wherein the plurality of battery modules are connected in series, and each battery module includes a plurality of battery cells connected in series; the first equalization circuit 1 is connected to the battery cells in the corresponding battery module, and is used to equalize the voltage of the battery cells in the corresponding battery module; each second equalization circuit 2 is connected to two adjacent battery modules, and is used to equalize the voltage of the two connected battery modules. In this way, each first equalization circuit 1 does not interfere with each other, and can equalize the voltage of each battery cell in each battery module. At the same time, each second equalization circuit 2 is used to equalize between each battery module, thereby reducing energy loss and improving the equalization speed. Since the first equalization circuit 1 and the second equalization circuit 2 work separately, the first equalization circuit 1 and the second equalization circuit 2 are simple to design and implement, easy to implement, low in complexity, and correspondingly low in cost.

[0059] The following is an exemplary description of the first balancing circuit 1. The description is given by taking a battery module including four battery cells as an example.

[0060] In one embodiment, Figure 2A schematic diagram of a first balancing circuit 1 provided in an embodiment of the present application is shown. The first balancing circuit 1 includes a first coupling inductor 11 and a plurality of first transmission branches 12 connected one-to-one with each battery cell in the battery module; the first coupling inductor 11 is connected to each first transmission branch 12 to transmit the energy of the battery cell with high voltage in the battery module to the battery cell with low voltage through each first transmission branch 12 and the first coupling inductor 11.

[0061] For each battery cell, the battery cell is connected to the corresponding first transmission branch 12, and the corresponding first transmission branch 12 is connected to the first coupling inductor 11, so the battery cell forms a loop with the first coupling inductor 11 through the corresponding first transmission branch 12. When the voltage of the battery cell is higher than the voltage of other battery cells in the battery module, the energy in the battery cell is transmitted to the first coupling inductor 11 through the corresponding first transmission branch 12. It can be understood that the first coupling inductor 11 is connected to other battery cells through other first transmission branches 12, so it is possible to further transmit energy to other battery cells with low voltage, thereby achieving energy balance, that is, voltage balance.

[0062] Similarly, when the cell voltage is lower than the voltages of other cells in the battery module, the voltages of other cells can also be transmitted to the first coupled inductor 11 through the corresponding first transmission branch 12, and then transmitted to the cell to achieve voltage balance.

[0063] The balancing circuit provided in the embodiment of the present application can quickly achieve energy balance inside the battery module if imbalance occurs inside the battery module, without relying on traditional step-by-step energy transfer between batteries. This greatly improves the balancing efficiency and reduces the loss during the energy transfer process.

[0064] In one embodiment, Figure 3 A schematic diagram of another first equalization circuit 1 provided in an embodiment of the present application is shown. Each first transmission branch 12 includes a first equalization switch 12A; the first equalization switch 12A is turned on under the control of a first equalization signal, so that the cell connected to the first transmission branch 12 where the first equalization switch 12A is located outputs its own energy to the first coupling inductor 11 through the first transmission branch 12 or receives energy transmitted by the first coupling inductor 11.

[0065] Optionally, the balancing circuit is connected to a controller, and each element is controlled by the controller.

[0066] Exemplarily, each first balancing switch 12A is connected to the controller through a corresponding driving circuit; the voltage detection circuit is connected to each battery cell and connected to the controller. In this way, the voltage detection circuit can detect the voltage of each battery cell in real time, and the controller reads the voltage of each battery cell detected by the voltage detection circuit to know whether there is an imbalance inside the battery module. When it is determined that there is an imbalance inside the battery module, the first balancing signal is transmitted to the first balancing switch 12A that needs to be turned on through the driving circuit, so that the first balancing switch 12A is turned on under the control of the first balancing signal. Among them, the battery cell connected to the first transmission branch 12 to which the turned-on first balancing switch 12A belongs is the battery cell that currently needs voltage balancing.

[0067] In this way, when the voltage of the battery cell connected to the first transmission branch 12 where the first balancing switch 12A is located is high, its own energy is output to the first coupling inductor 11 through the first transmission branch 12; when the voltage of the battery cell connected to the first transmission branch 12 where the first balancing switch 12A is located is low, the energy transmitted by the first coupling inductor 11 is received. It can be understood that the energy transmitted by the first coupling inductor 11 comes from other battery cells.

[0068] Optionally, the two first balancing switches 12A in the first balancing circuit 1 may be turned on at the same time to balance the voltages of the two cells at the same time.

[0069] Optionally, the first balancing switch 12A included in the first transmission branch 12 connected to the battery cell that does not currently need balancing may be turned off under the control of the first balancing signal.

[0070] In the energy storage system, each battery pack is composed of multiple groups of battery modules connected in series by copper bars, and each battery module is composed of multiple battery cells connected in series. When inconsistencies occur in the battery module, the use of traditional passive balancing circuits may cause energy waste and thermal management problems. At the same time, the balancing time may also be long, and when the battery cell capacity is large, the balancing effect is minimal. However, the present application can quickly and effectively balance the energy of the battery cells inside the battery module through the first balancing circuit 1.

[0071] In one embodiment, Figure 4A schematic diagram of another first equalization circuit 1 provided in an embodiment of the present application is shown. In which, the battery module includes a first battery cell B1, a second battery cell B2, a third battery cell B3 and a fourth battery cell B4; a plurality of first transmission branches 12 include a first energy transmission branch 121, a second energy transmission branch 122, a third energy transmission branch 123 and a fourth energy transmission branch 124; the first energy transmission branch includes a first switch 12A1 and is connected to the first battery cell B1; the second energy transmission branch includes a second switch 12A2 and is connected to the second battery cell B2; the third energy transmission branch includes a third switch 12A3 and is connected to the third battery cell B3; the fourth energy transmission branch includes a fourth switch 12A4 and is connected to the fourth battery cell B4.

[0072] That is, the first switch element 12A1 , the second switch element 12A2 , the third switch element 12A3 and the fourth switch element 12A4 are first balancing switch elements 12A in different first transmission branches 12 , and are all controlled by the first balancing signal.

[0073] Optionally, each first balancing switch 12A may be a semiconductor switch. Of course, it may also be other switches that can achieve the above functions, which are not fully exemplified here.

[0074] In one embodiment, the first switch element 12A1, the second switch element 12A2, the third switch element 12A3 and the fourth switch element 12A4 are switch tubes. In addition, the gates of the first switch element 12A1, the second switch element 12A2, the third switch element 12A3 and the fourth switch element 12A4 are all controlled by the first balanced signal, that is, the gates are connected to the controller, so as to be turned on or off under the control of the first balanced signal.

[0075] In addition, if Figure 5 A schematic diagram of another first equalization circuit 1 provided by an embodiment of the present application is shown. Among them, the positive electrode of the first battery cell B1 is connected to the drain electrode of the first switch element 12A1; the source electrode of the first switch element 12A1 is connected to the primary same-name terminal of the first coupling inductor 11 and the drain electrode of the second switch element 12A2; the primary opposite-name terminal of the first coupling inductor 11 is connected to the negative electrode of the first battery cell B1 and the positive electrode of the second battery cell B2; the negative electrode of the second battery cell B2 is connected to the source electrode of the second switch element 12A2; the secondary same-name terminal of the first coupling inductor 11 is connected to the source electrode of the third switch element 12A3 and the drain electrode of the fourth switch element 12A4; the drain electrode of the third switch element 12A3 is connected to the positive electrode of the third battery cell B3; the negative electrode of the third battery cell B3 is connected to the positive electrode of the fourth battery cell B4 and the secondary opposite-name terminal of the first coupling inductor 11; the source electrode of the fourth switch element 12A4 is connected to the negative electrode of the fourth battery cell B4. Figure 5 Middle W 11 is the primary side of the first coupled inductor 11, W 12is the secondary side of the first coupled inductor 11.

[0076] In one embodiment, the first equalization signal includes a first control signal and a second control signal with opposite levels; the first switch element 12A1 and the third switch element 12A3 are controlled by the first control signal, and the second switch element 12A2 and the fourth switch element 12A4 are controlled by the second control signal.

[0077] In this way, when there is an imbalance inside the battery module, the first switch element 12A1 and the third switch element 12A3 are turned on under the control of the first control signal and the second switch element 12A2 and the fourth switch element 12A4 are turned off under the control of the second control signal, and balance can be achieved between the first battery cell B1 and the third battery cell B3; the first switch element 12A1 and the third switch element 12A3 are turned off under the control of the first control signal and the second switch element 12A2 and the fourth switch element 12A4 are turned on under the control of the second control signal, and balance can be achieved between the second battery cell B2 and the fourth battery cell B4.

[0078] The balancing process of the first balancing circuit 1 is exemplarily described below by taking the case where the voltages of the first battery cell B1 , the second battery cell B2 , the third battery cell B3 and the fourth battery cell B4 decrease in sequence as an example.

[0079] In one embodiment, when the voltages of the first battery cell B1, the second battery cell B2, the third battery cell B3 and the fourth battery cell B4 decrease sequentially, the first switch element 12A1 and the third switch element 12A3 are turned on under the control of the first control signal and the second switch element 12A2 and the fourth switch element 12A4 are turned off under the control of the second control signal, voltage balance is achieved between the first battery cell B1 and the third battery cell B3; and the first coupling inductor 11 stores energy; then, the first switch element 12A1 and the third switch element 12A3 are turned off under the control of the first control signal and the second switch element 12A2 and the fourth switch element 12A4 are turned on under the control of the second control signal, at which time, the energy of the first coupling inductor 11 is transmitted to the second battery cell B2 and the fourth battery cell B4 to balance the voltages of the second battery cell B2 and the fourth battery cell B4.

[0080] Similarly, when the voltage of the third battery cell B3 is greater than the voltage of the first battery cell B1, the first switch element 12A1 and the third switch element 12A3 are turned on under the control of the first control signal and the second switch element 12A2 and the fourth switch element 12A4 are turned off under the control of the second control signal, the energy of the third battery cell B3 is transmitted to the first battery cell B1 through the first coupling inductor 11.

[0081] This solution uses two different balancing topologies, namely, coupled half-bridge circuit balancing and buck-boost circuit balancing, to achieve the effect of reducing the number of components required for the entire battery balancing system. In addition, this mode can simultaneously start multiple balancing circuits to work without interfering with each other, shortening the energy transfer path between batteries, reducing energy loss, increasing balancing speed, and reducing overall costs.

[0082] The following is an exemplary description of the second balancing circuit 2 based on the first balancing circuit 1. The description is also made by taking the battery module including 4 cells as an example.

[0083] In one embodiment, Figure 4 On the basis of Figure 6 The schematic diagram of the second balancing circuit 2 provided in the embodiment of the present application is shown. The second balancing circuit 2 includes a second coupling inductor 21 and two second transmission branches 22 corresponding to the two battery modules connected to the second balancing circuit 2; the second coupling inductor 21 is connected to each second transmission branch 22 to transmit the energy of the battery cell in the battery module with a higher voltage in the two adjacent battery modules to the battery cell in the battery module with a lower voltage in the two adjacent battery modules through each second transmission branch 22 and the second coupling inductor 21. It can be understood that Figure 6 FIG. 2 is a diagram illustrating the connection relationship of a single second equalizing circuit 2 .

[0084] As mentioned above, the second balancing circuit 2 can be connected to the cells in two adjacent battery modules respectively. Figure 6 As shown, the second balancing circuit 2 is connected to the B2 battery cell in one of the first balancing circuits 1 , and is simultaneously connected to the B1 battery cell in another first balancing circuit 1 .

[0085] In the balancing circuit provided in the embodiment of the present application, if there is an imbalance between two adjacent battery modules, the second balancing circuit 2 can achieve energy balancing across modules. This not only improves the efficiency of energy transfer, but also simplifies the complexity of the system control strategy. Among them, the entire balancing process can adopt open-loop control, which greatly reduces the possibility of control errors.

[0086] In one embodiment, Figure 7 1 is a schematic diagram of another second balancing circuit 2 provided in an embodiment of the present application. The two second transmission branches 22 include a first cross-module transmission branch 221 and a second cross-module transmission branch 222; two adjacent battery modules include a first battery module and a second battery module; the first cross-module transmission branch 221 and a first target battery cell (with Figure 7The second cross-module transmission branch 222 is connected to the second target battery cell in the second battery module (for example, B2 connected to the first cross-module transmission branch 221 in the example). Figure 7 Taking B1 connected by the second cross-module transmission branch 222 in the example) as an example; wherein the first target battery cell and the second target battery cell are connected in series, and the negative electrode of the first target battery cell is connected to the positive electrode of the second target battery cell.

[0087] In one embodiment, Figure 7 As shown, the first cross-module transmission branch 221 includes a fifth switch element 22A1 and is connected to the first target battery cell, and the second cross-module transmission branch 222 includes a sixth switch element 22A2 and is connected to the second target battery cell; when the fifth switch element 22A1 is turned on under the control of the second balanced signal, the first target battery cell outputs its own energy to the second coupled inductor or receives energy transmitted by the second coupled inductor through the first cross-module transmission branch 221; when the sixth switch element 22A2 is turned on under the control of the second balanced signal, the second target battery cell outputs its own energy to the second coupled inductor or receives energy transmitted by the second coupled inductor through the second cross-module transmission branch 222.

[0088] In this way, the inter-module balancing is achieved through the second balancing circuit 2, which greatly shortens the energy transfer path, reduces energy loss, and improves the balancing speed. The second balancing circuit 2 can be implemented through each second transmission branch and the second coupled inductor. While achieving the balancing effect, the circuit complexity is low and easy to implement. The entire balancing process can be controlled by open loop, which greatly reduces the possibility of control errors.

[0089] For example, in Figure 5 On the basis of Figure 8 A schematic diagram of another equalization circuit provided by an embodiment of the present application is shown. In which, the fifth switch element 22A1 and the sixth switch element 22A2 are switch tubes and the gates are controlled by the second equalization signal; the drain of the fifth switch element 22A1 is connected to the positive electrode of the first target cell; the source of the fifth switch element 22A1 is connected to the first end of the second coupling inductor and the drain of the sixth switch element 22A2; the second end of the second coupling inductor is connected to the positive electrode of the second target cell; the source of the sixth switch element 22A2 is connected to the negative electrode of the second target cell.

[0090] Optionally, the balancing circuit is connected to a controller, and each element is controlled by the controller.

[0091] Exemplarily, each fifth switch element 22A1 and sixth switch element 22A2 is connected to the controller through a corresponding drive circuit; when it is determined that there is an imbalance between the first target battery cell and the second target battery cell, that is, the two adjacent battery modules are unbalanced, the second balance signal is transmitted to the fifth switch element 22A1 or the sixth switch element 22A2 through the drive circuit, so that the fifth switch element 22A1 or the sixth switch element 22A2 is turned on under the control of the second balance signal.

[0092] Optionally, the switch element corresponding to the cell with higher voltage in the first target cell and the second target cell may be turned on first. For example, if the voltage of the first target cell is higher, the fifth switch element 22A1 is turned on first, so that the first target cell transmits energy to the second coupled inductor, and then the sixth switch element 22A2 is turned on and the fifth switch element 22A1 is turned off, so that the energy stored in the second coupled inductor is transmitted to the second target cell, so as to achieve the balance of the two cells, that is, to achieve the balance of the two battery modules.

[0093] In one embodiment, the second balancing signal includes a third control signal and a fourth control signal with opposite level values; the fifth switch 22A1 is controlled by the third control signal, and the sixth switch 22A2 is controlled by the fourth control signal. In this way, the balancing between the two battery modules can be achieved quickly and stably through switch control.

[0094] The following is an example of the case where the voltage of the first target battery cell is greater than the voltage of the second target battery cell to illustrate the balancing process of the second balancing circuit 2 .

[0095] Among them, when the voltage of the first target battery cell is greater than the voltage of the second target battery cell, the fifth switch element 22A1 is turned on under the control of the third control signal and the sixth switch element 22A2 is turned off under the control of the fourth control signal, the first target battery cell charges the second coupled inductor; when the fifth switch element 22A1 is turned off under the control of the third control signal and the sixth switch element 22A2 is turned on under the control of the fourth control signal, the energy stored in the second coupled inductor is transmitted to the second target battery cell to balance the voltages of the first target battery cell and the second target battery cell.

[0096] Similarly, when the voltage of the second target battery cell is greater than the voltage of the first target battery cell, the fifth switch element 22A1 is turned off under the control of the third control signal and the sixth switch element 22A2 is turned on under the control of the fourth control signal, the second target battery cell charges the second coupled inductor; then, the fifth switch element 22A1 is turned on under the control of the third control signal and the sixth switch element 22A2 is turned off under the control of the fourth control signal, and the energy stored in the second coupled inductor is transmitted to the first target battery cell to balance the voltages of the first target battery cell and the second target battery cell.

[0097] In one embodiment, the present application also provides a method for balancing an energy storage battery, which is used in a controller connected to the balancing circuit described in any of the above embodiments, and the method includes: when the voltages of the battery cells in the battery module are inconsistent, controlling the first balancing circuit to balance the voltages of the battery cells in the connected battery module; wherein the first balancing circuit is connected to the battery cells in the corresponding battery module; when the voltages of two adjacent battery modules are inconsistent, controlling the second balancing circuit to balance the voltages of the two connected battery modules; wherein the second balancing circuit is connected to the two adjacent battery modules.

[0098] For other limitations of this method, please refer to the above description and will not be repeated here.

[0099] For ease of understanding, the balancing circuit provided in the embodiment of the present application is described below with a complete embodiment. In the embodiment of the present application, based on the analysis of the existing active balancing circuit, a hybrid topology energy storage battery group balancing circuit is provided from the perspectives of improving the balancing speed of the energy storage battery and reducing the cost of the equalizer. The balancing topology of the energy storage battery group balancing circuit is suitable for active balancing at the energy storage Cell level.

[0100] Specifically, the energy storage battery pack balancing circuit provided in the embodiment of the present application adopts two different balancing topologies, namely, the coupled half-bridge circuit balancing and the buck-boost circuit for voltage balancing, which achieves the effect of reducing the number of components required for the entire battery balancing system. In addition, the circuits do not interfere with each other, and at the same time shorten the energy transfer path between batteries, reduce energy loss, increase the balancing speed, and reduce the overall cost, which is suitable for scenarios requiring a large number of batteries.

[0101] The energy storage battery pack balancing circuit is suitable for batteries with a cell number that is a multiple of 4. The battery is divided into several battery modules, each of which is equipped with a special coupling half-bridge circuit to manage four batteries. In addition, the battery modules are also connected through a buck-boost circuit to form a whole. When there is an imbalance in the cells between the battery modules, the balancing function between the battery modules is activated. This design effectively shortens the distance and time of energy transmission, thereby reducing energy loss.

[0102] In addition, the energy storage battery pack balancing circuit allows two balancing topologies with different structures to participate in the balancing process at the same time without interfering with each other. This provides a more stable and efficient balancing mechanism for the battery, further enhancing the performance and reliability of the battery system.

[0103] In summary, the energy storage battery pack balancing circuit provides an efficient, reliable and cost-effective balancing solution for the battery through the combination of two hybrid circuit structures and a simplified control strategy.

[0104] Please refer to Fig. 9 , showing a schematic diagram of an energy storage battery pack balancing circuit provided in an embodiment of the present application.

[0105] No. In a coupled half-bridge circuit, the lithium battery cell B i1 The positive electrode of is used as the first terminal of the i-th coupled half-bridge circuit; the first terminal is connected to the switch tube S i1 The drain connection of the switch tube S i1 The source and coupling inductor L i The primary side of the same name and the switch tube S i2 The drain connection of i The primary side of the anonym end and B i1 The negative electrode and B i2 The positive electrode of the cell B is connected and serves as the second terminal of the i-th coupled half-bridge circuit; i2 The negative electrode and the switch tube S i2 and serves as the third terminal of the i-th coupled half-bridge circuit; i The secondary side of the same name end and the switch tube S (n+i)1 The source and switch S (n+i)2 The drain connection of the switch tube S (n+i)1 The drain and B (n+i)1 The positive connection of B (n+i)1 The negative electrode and B (n+i)2 The positive electrode and L i The secondary side of the switch tube S (n+i)2 The source and B (n+i)2 negative connection.

[0106] For the buck-boost circuit, taking the first buck-boost circuit as an example, the switch tube S k1 The drain of the switch tube S is connected to the second terminal of the first coupled half-bridge circuit; k1 The source and inductor L k1 The left end and the switch tube S k2 The drain of k1 The right end of the switch tube S is connected to the third terminal of the first coupled half-bridge circuit and the first terminal of the second coupled half-bridge circuit; k2 The source of is connected to the second terminal of the second coupled half-bridge circuit.

[0107] Specifically, when the voltage of the battery cells in the battery module corresponding to the coupled half-bridge circuit is inconsistent, the controller of the balancing system will realize the energy transfer between the battery cells in the coupled half-bridge circuit by controlling the corresponding switch tube. When the voltage of the battery module corresponding to the i-th coupled half-bridge circuit is inconsistent with that of the battery module corresponding to the (i+1)-th coupled half-bridge circuit, the controller of the balancing system will realize the energy transfer between the battery cells by controlling the switch tube in the buck-boost circuit connected to the two modules.

[0108] Among them, the control strategy of the switch tube of the coupled half-bridge circuit is: i1 and S (n+i)1 For the same control signal, S i2 and S (n+i)2 are the same control signal, and the two control signals form complementary signals. i1 , S (n+i)1 , S i2 , S (n+i)2 The driving signal is Fig.10 As shown. The control strategy of the switch tube of the buck-boost circuit is: S k(2(j-1)-1) and S k(2j-1) The control signals of the switch tube S are complementary to each other. k(2(j-1)-1) and S k(2j-1) The driving signal is Fig.11 As shown. And, when the circuit is running, the coupling inductor L in the coupled half-bridge circuit i The current i L The waveform is as Fig.10 As shown. Inductor L in the buck-boost circuit ki The current i Lki The waveform is as Fig.11 As shown. Among them, i i1 Indicates the current flowing through the coupled inductor L i The current on the primary side; i (n+i)1 Indicates the current flowing through the coupled inductor L i The current on the secondary side; i Lk1 Indicates the current flowing through the inductor L k1 The current u GSi1 、u S(n+i)1 、u Si2 、u S(n+i)2 The switch tube S i1 , S (n+i)1 , S i2 , S (n+i)2 The driving signal u Sk1 、u Sk2 The switch tube S k1 , S k2It should be noted that the driving signals of the switch tubes in other buck-boost circuits are the same. T is the switching period of the switch tube.

[0109] In a switching cycle, when the cell voltage U Bi1 >U Bi2 >U B(n+i)1 > U B(n+i)2 When the topological operation mode diagram of the coupled half-bridge circuit corresponds to Fig.12 and Fig.13 .

[0110] In a switching cycle, when there is a cell voltage imbalance between adjacent battery modules, the buck-boost circuit plays a balancing role. The topological operation mode diagrams of the buck-boost circuit correspond to Fig.14 and Fig.15 .

[0111] Fig.12 In the balanced mode of the coupled half-bridge circuit shown in the figure: during the t0-t1 period, the switch tube S i1 and S (n+i)1 At the same time, the switch tube S i2 and S (n+i)2 At the same time, turn off. i1 , S i1 and L i The primary side of B forms a loop; (n+i)1 , S (n+i)1 and L i The secondary side of the battery cell B forms a loop; at this time, i1 Through this circuit, L i Charging. At the same time, L i The same-name terminal of the secondary side senses a positive voltage at the top and a negative voltage at the bottom, giving B (n+i)1 Charging. The direction of the loop current is as follows Fig.12 shown.

[0112] Fig.13 In the balanced mode of the coupled half-bridge circuit shown in the figure: during the t1-t2 period, the switch tube S i1 and S (n+i)1 At the same time, the switch tube S i2 and S (n+i)2 Conducting at the same time. i2 , S i2 and L i The primary side of B forms a loop; (n+i)2 , S (n+i)2 and L i The secondary side forms a loop; at this time, the i The energy in the primary side is fed to battery B through this circuit. i2 Charging. At the same time, L i The secondary side senses a positive voltage at the bottom and a negative voltage at the top, giving B(n+i)2 Charging. The direction of the loop current is as follows Fig.13 shown.

[0113] Fig.14 In the balanced mode of the buck-boost circuit shown: t k0 -t k1 stage, the switch tube S k1 The switch tube S is turned on. k2 Turn off. Inductor L k1 , S k1 and B 12 A loop is formed; at this time, B 12 Through the loop to L k1 Charging. The direction of the loop current is as follows Fig.14 shown.

[0114] Fig.15 In the balanced mode of the buck-boost circuit shown: t k1 -t k2 stage, the switch tube S k1 Turn off, switch S k2 Conductive. Inductor L k1 , S k2 and B 21 A loop is formed; at this time, the current stored in the inductor L k1 The energy in the circuit is given to B through 21 Charging. The direction of the loop current is as follows Fig.15 shown.

[0115] The above energy storage battery pack balancing circuit has the following advantages:

[0116] 1. Topological structure advantages: It adopts two topological structures with different equalization methods, combining a coupled half-bridge circuit and a buck-boost equalization circuit. Compared with the traditional bidirectional buck-boost circuit, the new equalizer significantly reduces the number of required inductors and switch tubes, which not only simplifies the circuit design, but also greatly reduces the manufacturing cost of the equalization circuit, and can also reduce the circuit size, making it more flexible and convenient in practical applications, and more competitive in the market.

[0117] 2. Advantages in balancing performance: In terms of balancing speed, the balancing circuit shows obvious advantages. Compared with the traditional bidirectional buck-boost circuit between adjacent batteries, it has a faster balancing speed and higher balancing efficiency. This advantage is mainly due to the fact that the new balancing circuit shortens the energy transfer path, thereby reducing energy loss during the transfer process. This means that the battery can reach a balanced state in a shorter time, improving the efficiency and reliability of the entire battery system, and allowing the battery pack to reach an ideal balanced state faster.

[0118] 3. Control strategy advantage: In terms of the control strategy of the balancing system, the coupled half-bridge circuit and the buck-boost circuit in the balancing topology adopt a simple open-loop control method without the need for complex control algorithms. This control strategy not only simplifies the control logic, but also reduces the possibility of control errors, enhances the stability and reliability of the system, and enables the balancing circuit to achieve consistency between battery modules more quickly and effectively, thereby eliminating various problems caused by differences in battery performance. Overall, this control strategy makes the operation of the balancer more efficient and reliable.

[0119] 4. Advantages of energy transfer path: In terms of energy transfer path, the series-connected cells are divided into multiple battery modules, each of which has a balancing circuit, and there are circuits between modules. When the battery module is unbalanced, there is no need to transfer energy between adjacent batteries step by step like the traditional balancing circuit, but the half-bridge circuit is coupled to balance each cell. This balancing method greatly shortens the energy transfer path, reduces energy loss, and increases the balancing speed.

[0120] Therefore, it has the advantages of fast balancing speed, high balancing efficiency, fewer equalizer components and low use cost.

[0121] In one embodiment, a computer device is further provided, including a memory and a processor, wherein a computer program is stored in the memory, and the processor implements the steps in the above method embodiment when executing the computer program.

[0122] In one embodiment, a computer-readable storage medium is provided, on which a computer program is stored. When the computer program is executed by a processor, the steps in the above method embodiment are implemented.

[0123] In one embodiment, a computer program product is provided, including a computer program, which implements the steps in the above method embodiment when executed by a processor.

[0124] The technical features of the above embodiments may be combined arbitrarily. 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.

[0125] The above-described embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the present application. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the present application shall be subject to the attached claims.

Claims

1. An equalization circuit, characterized in that: The equalization circuit comprises: A plurality of first balancing circuits corresponding to a plurality of battery modules in the battery; wherein the plurality of battery modules are connected in series, and each of the battery modules comprises a plurality of battery cells connected in series; the first balancing circuits are connected to the battery cells in the corresponding battery modules, and are used to balance the voltages of the battery cells in the corresponding battery modules; A plurality of second balancing circuits; each of the second balancing circuits is connected to two adjacent battery modules and is used for balancing the voltages of the two connected battery modules.

2. The equalization circuit according to claim 1, characterized in that: The first balancing circuit includes a first coupling inductor and a plurality of first transmission branches connected one-to-one with each battery cell in the battery module; The first coupled inductor is connected to each of the first transmission branches to transmit energy of a battery cell with a high voltage in the battery module to a battery cell with a low voltage through each of the first transmission branches and the first coupled inductor.

3. The equalizing circuit according to claim 2, characterized in that: Each of the first transmission branches comprises a first balancing switch; The first balancing switch is turned on under the control of the first balancing signal, so that the battery cell connected to the first transmission branch where the first balancing switch is located outputs its own energy to the first coupled inductor through the first transmission branch or receives energy transmitted by the first coupled inductor.

4. The equalizing circuit according to claim 3, characterized in that: The battery module includes a first battery cell, a second battery cell, a third battery cell and a fourth battery cell; the multiple first transmission branches include a first energy transmission branch, a second energy transmission branch, a third energy transmission branch and a fourth energy transmission branch; the first energy transmission branch includes a first switch element and is connected to the first battery cell; the second energy transmission branch includes a second switch element and is connected to the second battery cell; the third energy transmission branch includes a third switch element and is connected to the third battery cell; the fourth energy transmission branch includes a fourth switch element and is connected to the fourth battery cell.

5. The equalizing circuit according to claim 4, characterized in that: The first switch element, the second switch element, the third switch element and the fourth switch element are switch tubes and the gates thereof are controlled by the first equalization signal; The positive electrode of the first battery cell is connected to the drain electrode of the first switch element; the source electrode of the first switch element is connected to the primary same-name end of the first coupled inductor and the drain electrode of the second switch element; The primary opposite-polarity terminals of the first coupled inductor are connected to the negative electrode of the first battery cell and the positive electrode of the second battery cell; The negative electrode of the second battery cell is connected to the source electrode of the second switch element; The secondary side same-name terminal of the first coupled inductor is connected to the source of the third switch element and the drain of the fourth switch element; The drain electrode of the third switch is connected to the positive electrode of the third battery cell; the negative electrode of the third battery cell is connected to the positive electrode of the fourth battery cell and the secondary side opposite-name terminal of the first coupled inductor; The source electrode of the fourth switch element is connected to the negative electrode of the fourth battery cell.

6. The equalizing circuit according to claim 5, characterized in that: The first equalization signal includes a first control signal and a second control signal with opposite level values; the first switch element and the third switch element are controlled by the first control signal, and the second switch element and the fourth switch element are controlled by the second control signal.

7. The equalizing circuit according to claim 6, characterized in that: When the voltages of the first battery cell, the second battery cell, the third battery cell and the fourth battery cell decrease in sequence, When the first switch element and the third switch element are turned on under the control of the first control signal and the second switch element and the fourth switch element are turned off under the control of the second control signal, voltage balance is achieved between the first battery cell and the third battery cell; and the first coupled inductor stores energy; When the first switch element and the third switch element are turned off under the control of the first control signal and the second switch element and the fourth switch element are turned on under the control of the second control signal, the energy of the first coupled inductor is transmitted to the second battery cell and the fourth battery cell to balance the voltages of the second battery cell and the fourth battery cell.

8. The equalizing circuit according to claim 1, characterized in that: The second balancing circuit includes a second coupled inductor and two second transmission branches corresponding one to one to two battery modules connected to the second balancing circuit; The second coupled inductor is connected to each of the second transmission branches to transmit the energy of the battery cells in the battery module with a higher voltage in two adjacent battery modules to the battery cells in the battery module with a lower voltage in the two adjacent battery modules through each of the second transmission branches and the second coupled inductor.

9. The equalizing circuit according to claim 8, characterized in that: The two second transmission branches include a first cross-module transmission branch and a second cross-module transmission branch; the two adjacent battery modules include a first battery module and a second battery module; The first cross-module transmission branch is connected to a first target battery cell in the first battery module, and the second cross-module transmission branch is connected to a second target battery cell in the second battery module; Wherein, the first target battery cell and the second target battery cell are connected in series, and the negative electrode of the first target battery cell is connected to the positive electrode of the second target battery cell.

10. The equalizing circuit according to claim 9, characterized in that: The first cross-module transmission branch includes a fifth switch and is connected to the first target battery cell, and the second cross-module transmission branch includes a sixth switch and is connected to the second target battery cell; When the fifth switch is turned on under the control of the second equalization signal, the first target cell outputs its own energy to the second coupled inductor through the first cross-module transmission branch or receives energy transmitted by the second coupled inductor; When the sixth switch is turned on under the control of the second equalization signal, the second target battery cell outputs its own energy to the second coupled inductor through the second cross-module transmission branch or receives energy transmitted by the second coupled inductor.

11. The equalizing circuit according to claim 10, characterized in that: The fifth switch element and the sixth switch element are switch tubes and the gates thereof are controlled by the second equalization signal; The drain of the fifth switch is connected to the positive electrode of the first target cell; the source of the fifth switch is connected to the first end of the second coupled inductor and the drain of the sixth switch; The second end of the second coupled inductor is connected to the positive electrode of the second target battery cell; the source electrode of the sixth switch element is connected to the negative electrode of the second target battery cell.

12. The equalizing circuit according to claim 11, characterized in that: The second equalization signal includes a third control signal and a fourth control signal with opposite level values; the fifth switch element is controlled by the third control signal, and the sixth switch element is controlled by the fourth control signal.

13. The equalizing circuit according to claim 12, characterized in that: When the voltage of the first target cell is greater than the voltage of the second target cell, When the fifth switch is turned on under the control of the third control signal and the sixth switch is turned off under the control of the fourth control signal, the first target cell charges the second coupled inductor; When the fifth switch element is turned off under the control of the third control signal and the sixth switch element is turned on under the control of the fourth control signal, the energy stored in the second coupled inductor is transmitted to the second target battery cell to balance the voltages of the first target battery cell and the second target battery cell.

14. A method for balancing an energy storage battery, characterized in that: In a controller connected to the equalizing circuit according to any one of claims 1 to 13, the method comprises: When the voltages of the cells in the battery module are inconsistent, controlling the first balancing circuit to balance the voltages of the cells in the connected battery module; wherein the first balancing circuit is connected to the cells in the corresponding battery module; When the voltages of two adjacent battery modules are inconsistent, the second balancing circuit is controlled to balance the voltages of the two connected battery modules; wherein the second balancing circuit is connected to the two adjacent battery modules.

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