Active equalization circuit, method and device and energy storage system

Abstract

The invention provides an active equalization circuit, method and device and an energy storage system, and relates to the technical field of battery management. The active equalization circuit comprises a one-way flyback power supply module; the first end of each first switch module in the N first switch modules is connected with the input end of the one-way flyback power supply module, and the second ends of the N first switch modules are connected with the output ends of the N battery cells respectively; the first end of each second switch module in the N second switch modules is connected with the output end of the one-way flyback power supply module, and the second ends of the N second switch modules are connected with the input ends of the N battery cells respectively; and the control module is connected with the control ends of the N first switch modules and the control ends of the N second switch modules. According to the invention, the active equalization effect between the non-adjacent battery cells is improved, and the convenience of active equalization between the non-adjacent battery cells is improved.

Description

Technical Field

[0001] The present application relates to the field of battery management technology, and more specifically, to an active balancing circuit, method, device, and energy storage system. Background Art

[0002] As the capacity of energy storage cells continues to increase, people are beginning to pay attention to the voltage consistency of each cell to avoid a significant drop in the battery capacity of the entire battery pack due to a voltage inconsistency in one cell within the battery pack. Due to the increase in cell capacity, earlier passive balancing solutions can no longer effectively meet the cell consistency requirements.

[0003] like Figure 9 As shown, in the related art, active balancing between adjacent cells is achieved by installing a bidirectional switching power supply, inductor, capacitor, etc. between the two adjacent cells, but it is not possible to effectively perform active balancing between non-adjacent cells. When faced with the problem of active balancing between non-adjacent cells, active balancing can only be performed by gradually transferring adjacent cells, resulting in low efficiency and difficult operation of active balancing between non-adjacent cells. Summary of the Invention

[0004] The present application aims to solve the problems of low efficiency and difficult operation of active balancing between non-adjacent battery cells in the prior art or related art.

[0005] To this end, a first aspect of the present application proposes an active balancing circuit.

[0006] The second aspect of the present application proposes an active balancing method.

[0007] A third aspect of the present application provides an active balancing device.

[0008] A fourth aspect of the present application provides an active balancing device.

[0009] A fifth aspect of the present application provides a readable storage medium.

[0010] The sixth aspect of the present application proposes an energy storage system.

[0011] In view of this, according to a first aspect of the present application, an active balancing circuit is proposed, which is applied to an energy storage system. The energy storage system includes a battery module, and the battery module includes: N battery cells, where N is an integer greater than 1. The active balancing circuit includes: a unidirectional flyback power supply module; N first switch modules, wherein the first end of each of the N first switch modules is connected to the input end of the unidirectional flyback power supply module, and the second ends of the N first switch modules are respectively connected to the output ends of the N battery cells; N second switch modules, wherein the first end of each of the N second switch modules is connected to the output end of the unidirectional flyback power supply module, and the second ends of the N second switch modules are respectively connected to the input ends of the N battery cells; and a control module, wherein the control module is connected to the control ends of the N first switch modules and the control ends of the N second switch modules, wherein the control module is used to control the on-off states of the N first switch modules and the N second switch modules according to N voltage values corresponding to the N battery cells, so as to actively balance the charge of the N battery cells.

[0012] In the technical solution of the present application, the input and output ends of each battery cell in the battery pack are connected to a unidirectional flyback power supply module through a first switch module and a second switch module respectively, and the control module can control the on and off states of each first switch module and the second switch module, so that the control module can actively balance the power of each battery cell in the battery module, thereby improving the active balancing effect between non-adjacent battery cells and simplifying the convenience of active balancing between non-adjacent battery cells.

[0013] In some technical solutions, optionally, the control module includes: a sampling unit, the sampling end of the sampling unit is connected to N battery cells, and the sampling unit is used to collect N voltage values corresponding to the N battery cells; a first control unit, used to control the on-off state of N first switch modules according to the N voltage values; a second control unit, connected to the control end of the N second switch modules, and the second control unit is used to control the on-off state of the N second switch modules according to the N voltage values; wherein the second control unit is integrated with the sampling unit.

[0014] In the technical solution of the present application, the control module includes a first control unit and a second control unit for controlling the first switch module and the second switch module respectively, and a sampling unit for collecting the voltage value of each battery cell. The sampling unit collects the voltage values of multiple battery cells, so that the control module can flexibly control the active balancing of multiple battery cells, and the integrated arrangement of the sampling unit and the second control unit can further reduce the space occupied by the active balancing circuit in the energy storage control system.

[0015] In some technical solutions, optionally, the sampling unit and the second control unit are integrated into a front-end analog chip; and / or the first control unit is arranged on a main control chip.

[0016] In the technical solution of the present application, by using the main control chip in the battery management system as the first control unit in the active balancing circuit, and using the front-end analog chip in the battery management system as the sampling unit and the second control unit in the active balancing circuit, there is no need to set up an additional active balancing chip in the battery management system, which reduces the dependence of the battery management system on the procurement of active balancing chips, thereby reducing the production cost and maintenance cost of the battery management system.

[0017] In some technical solutions, optionally, the active balancing circuit also includes: N isolated optocoupler modules, the input ends of the N isolated optocoupler modules are all connected to the first control unit, and the output ends of the N isolated optocoupler modules are respectively connected to the control ends of the N first switch modules; a first power supply module, the output end of the first power supply module is connected to the N isolated optocoupler modules, and the first power supply module is used to power the N isolated optocoupler modules.

[0018] In the technical solution of the present application, the isolation optocoupler module isolates the first control unit and the first switch module without direct electrical connection by converting the electrical signal into an optical signal and then into an electrical signal, thereby avoiding damage to the first control unit caused by the reverse electromotive force or drain voltage mutation generated when the first switch module is switched on and off.

[0019] In some technical solutions, optionally, the control module also includes: N driving modules, the first ends of the N driving modules are connected to the output end of the second control unit, the second ends of the N driving modules are respectively connected to the control ends of the N second switch modules, and the N driving modules are used to output driving signals to the N second switch modules respectively.

[0020] In the technical solution of the present application, by setting a driving module in the second control unit, it is possible to prevent the reverse high voltage in the second switch module from being transmitted to the second control unit, and it is also possible to convert the control signal output by the second control unit into a corresponding level driving signal of the second switch module, thereby improving the operation of the second control unit and the stability of the driving of the second switch module.

[0021] In some technical solutions, optionally, the active balancing circuit further includes: a second power supply module connected to the power supply ends of the N second switch modules, and the second power supply module is used to supply power to the N second switch modules.

[0022] In the technical solution of the present application, a second power supply module is also provided in the active balancing circuit, and the second power supply module can supply power to the second switch module, so that the second control unit can stably drive the second switch module through the driving module, further improving the stability of the front-end analog chip driving the second switch module when the second control unit is integrated in the front-end analog chip.

[0023] In some technical solutions, optionally, the first switch module includes: a first switch element, the first switch element is arranged between the positive electrode of the battery cell and the positive electrode of the input terminal of the unidirectional flyback power supply module; a second switch element, the second switch element is arranged between the negative electrode of the battery cell and the negative electrode of the input terminal of the unidirectional flyback power supply module;

[0024] The second switch module includes: a third switch element, which is arranged between the positive pole of the battery cell and the positive pole of the output end of the unidirectional flyback power supply module; and a fourth switch element, which is arranged between the negative pole of the battery cell and the negative pole of the output end of the unidirectional flyback power supply module.

[0025] In the technical solution of the present application, by arranging a first switch element and a second switch element respectively connected to the positive and negative poles of the battery cell in the first switch module, and arranging a third switch element and a fourth switch element respectively connected to the positive and negative poles of the battery cell in the second switch module, a charging circuit is formed at the input end of each battery cell and a discharge circuit is formed at the output end of each battery cell, thereby improving the stability of active balancing of the battery cells.

[0026] According to the second aspect of the present application, an active balancing method is proposed, which is applied to the active balancing circuit in any of the above embodiments. The active balancing method includes: obtaining N voltage values corresponding to N battery cells, where N is an integer greater than 1; according to the N voltage values, controlling the first target switch module among the N first switch modules to be turned on, and controlling the second target switch module among the N second switch modules to be turned on, so as to actively discharge the first battery cell and actively charge the second battery cell among the N battery cells; wherein the first target switch module is connected to the first battery cell, the second target switch module is connected to the second battery cell, and the voltage value of the first battery cell is greater than the voltage value of the second battery cell.

[0027] In an embodiment of the present application, the input and output ends of each battery cell in the battery pack are connected to a unidirectional flyback power supply module through a first switch module and a second switch module respectively, and the control module can control the on and off states of each first switch module and the second switch module, actively discharge the first battery cell with a higher voltage, and actively charge the second battery cell with a lower voltage, so that the control module can actively balance each battery cell in the battery pack, thereby improving the active balancing effect between non-adjacent battery cells and simplifying the convenience of active balancing between non-adjacent battery cells.

[0028] According to a third aspect of the present application, an active balancing device is proposed, which is applied to the active balancing circuit in any of the above embodiments. The active balancing device includes: an acquisition module, used to obtain N voltage values corresponding to N battery cells; a control module, used to control the conduction of a first target switch module among N first switch modules, and control the conduction of a second target switch module among N second switch modules, based on the N voltage values, so as to actively discharge the first battery cell and actively charge the second battery cell among the N battery cells; wherein the first target switch module is connected to the first battery cell, the second target switch module is connected to the second battery cell, and the voltage value of the first battery cell is greater than the voltage value of the second battery cell.

[0029] In an embodiment of the present application, the input and output ends of each battery cell in the battery pack are connected to a unidirectional flyback power supply module through a first switch module and a second switch module respectively, and the control module can control the on and off states of each first switch module and the second switch module, actively discharge the first battery cell with a higher voltage, and actively charge the second battery cell with a lower voltage, so that the control module can actively balance each battery cell in the battery pack, thereby improving the active balancing effect between non-adjacent battery cells and simplifying the convenience of active balancing between non-adjacent battery cells.

[0030] According to a fourth aspect of the present application, an active balancing device is provided. The active balancing device includes a processor and a memory. The memory stores a program or instruction. When executed by the processor, the program or instruction implements the steps of the active balancing method described in any of the above technical solutions. Therefore, the active balancing device has all the beneficial effects of the active balancing method described in any of the above technical solutions, and will not be further described here.

[0031] According to the fifth aspect of the present application, a readable storage medium is proposed, on which a program or instruction is stored. When the program or instruction is executed by a processor, the steps of the active balancing method in any of the above-mentioned technical solutions are implemented, thereby having all the beneficial technical effects of the active balancing method in any of the above-mentioned technical solutions.

[0032] According to the sixth aspect of the present application, an energy storage system is proposed, including: a battery module, including multiple battery cells; a battery management system, including the active balancing circuit in any of the above technical solutions, actively balancing the power of multiple battery cells in the battery module based on the active balancing circuit; and / or, executing the active balancing method in any of the above technical solutions, thereby having the active balancing circuit in any of the above technical solutions; and / or the active balancing method in any of the above technical solutions, which will not be repeated here.

[0033] Additional aspects and advantages of the present application will become apparent in the following description or may be learned through practice of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] The above and / or additional aspects and advantages of the present application will become apparent and easily understood from the description of the embodiments in conjunction with the following drawings, in which:

[0035] Figure 1 One of the circuit topology diagrams of an active balancing circuit provided in some embodiments of the present application is shown;

[0036] Figure 2 FIG2 shows a second circuit topology diagram of an active balancing circuit provided in some embodiments of the present application;

[0037] Figure 3 FIG3 shows a third circuit topology diagram of an active balancing circuit provided in some embodiments of the present application;

[0038] Figure 4 FIG4 shows a fourth circuit topology diagram of an active balancing circuit provided in some embodiments of the present application;

[0039] Figure 5 A schematic flow chart of an active balancing method provided in some embodiments of the present application is shown;

[0040] Figure 6 One of the structural block diagrams of an active equalization device is shown in some embodiments of the present application;

[0041] Figure 7 A second structural block diagram of an active balancing device is shown in some embodiments of the present application;

[0042] Figure 8 A structural block diagram of an energy storage system is shown in some embodiments of the present application;

[0043] Figure 9 The topology diagram of the active balancing circuit in the related art is shown.

[0044] The reference numerals are as follows:

[0045] 10 battery module, 11 battery cell, 100 active balancing circuit, 101 unidirectional flyback power supply module, 110 first switch module, 111 first switch element, 112 second switch element, 120 second switch module, 121 third switch element, 122 fourth switch element, 130 control module, 131 sampling unit, 132 first control unit, 133 second control unit, 134 front-end analog chip, 135 main control chip, 140 first power supply module, 150 isolation optocoupler module, 160 drive module, 170 second power supply module, 21 first end of the first switch module, 22 second end of the first switch module, 23 control end of the first switch module, 31 first end of the second switch module, 32 second end of the second switch module, 33 control end of the second switch module, 41 input end of the battery cell, 42 output end of the battery cell, 51 input end of the unidirectional flyback power supply module, 52 output end of the unidirectional flyback power supply module. DETAILED DESCRIPTION

[0046] In order to more clearly understand the above-mentioned objectives, features and advantages of the present application, the present application is further described in detail below in conjunction with the accompanying drawings and specific embodiments. It should be noted that, in the absence of conflict, the features of this embodiment and the embodiments can be combined with each other.

[0047] In the following description, many specific details are set forth to facilitate a full understanding of the present application. However, the present application may also be implemented in other ways different from those described herein. Therefore, the scope of protection of the present application is not limited to the specific embodiments disclosed below.

[0048] Refer to the following Figures 1 to 8 An active balancing circuit, method, device, and energy storage system according to some embodiments of the present application are described.

[0049] According to one embodiment of the present application, Figure 1 FIG1 shows one of the circuit topology diagrams of an active balancing circuit provided in some embodiments of the present application. Figure 2 FIG2 shows a second circuit topology diagram of an active balancing circuit provided in some embodiments of the present application, such as Figure 1 and Figure 2As shown, an active balancing circuit 100 is proposed, which is applied to an energy storage system. The energy storage system includes a battery module 10, and the battery module 10 includes N battery cells 11, where N is an integer greater than 1. The active balancing circuit 100 includes: a unidirectional flyback power supply module 101; N first switch modules 110, wherein the first end 21 of each of the N first switch modules 110 is connected to the input end 51 of the unidirectional flyback power supply module 101, and the second ends 22 of the N first switch modules 110 are respectively connected to the output ends 42 of the N battery cells 11; N second switch modules 120, wherein the N second switch modules 120 are connected to the output ends 42 of the N battery cells 11; 0, the first end 31 of each second switch module 120 is connected to the output end 52 of the unidirectional flyback power supply module 101, and the second ends 32 of the N second switch modules 120 are respectively connected to the input ends 41 of the N battery cells 11; the control module 130, the control module 130 is connected to the control ends 23 of the N first switch modules 110 and the control ends 33 of the N second switch modules 120, wherein the control module 130 is used to control the on and off states of the N first switch modules 110 and the N second switch modules 120 according to the N voltage values corresponding to the N battery cells 11, so as to actively balance the power of the N battery cells 11.

[0050] In this embodiment, the active balancing circuit 100 is applied to an energy storage system, which includes a battery module 10. The battery module 10 includes N battery cells 11. The battery cell 11 is the smallest energy storage unit in the battery pack. Since the voltage and capacity of a single battery cell 11 are limited and cannot meet the needs of high-power equipment, a battery pack is formed by connecting multiple battery cells 11 in series and in parallel. Multiple battery cells 11 connected in series can increase the voltage of the battery module 10, and multiple battery cells 11 connected in parallel can increase the capacity of the battery module 10.

[0051] In this embodiment, when charging the battery module 10, the voltages of the multiple cells 11 in the battery module 10 may be inconsistent. When the voltages of the multiple cells 11 are inconsistent, the battery capacity of the entire battery module 10 decreases. In this case, active balancing is required to maintain voltage consistency among the multiple cells 11. Specifically, the principle of active balancing is to charge the lower voltage cell 11 with the higher voltage cell 11, thereby reducing the voltage difference between the multiple cells 11.

[0052] In this embodiment, the active balancing circuit 100 includes a switch module array provided at the output ends of N battery cells 11, and a switch module array provided at the input ends of N battery cells 11. The switch module array located at the output ends of the N battery cells 11 includes N first switch modules 110. The first switch modules 110 are connected between the unidirectional flyback power supply module 101 and the output ends 42 of the battery cells 11. By controlling the on / off states of the N first switch modules 110, the on / off state between the output ends 42 of the battery cells 11 and the unidirectional flyback power supply module 101 can be controlled. That is, when the first switch module 110 is on, the corresponding battery cell 11 can be discharged to the unidirectional flyback power supply module 101 through the first switch module 110. Module 101; the switch module array located at the input end of N battery cells 11 includes N second switch modules 120, and the second switch module 120 is connected between the unidirectional flyback power supply module 101 and the input end 41 of the battery cell 11. By controlling the on-off state of the N second switch modules 120, the on-off state between the input end 41 of the battery cell 11 and the unidirectional flyback power supply module 101 can be controlled, that is, when the second switch module 120 is turned on, the unidirectional flyback power supply module 101 can charge the corresponding battery cell 11. Exemplarily, the first switch module 110 and the second switch module 120 are both selected as NMOS (N-channel Metal-Oxide-Semiconductor Field-Effect Transistor, N-channel Metal-Oxide-Semiconductor Field-Effect Transistor) tubes.

[0053] Exemplarily, the unidirectional flyback power supply module 101 may be a distributed unidirectional flyback power supply, or a chip-level unidirectional flyback power supply.

[0054] Specifically, by connecting the output end 42 and the input end of each battery cell 11 in the N battery cells 11 to the first switch module 110 and the second switch module 120 respectively, and each battery cell 11 is connected to the unidirectional flyback power supply module 101 through the first switch module 110 and the second switch module 120, that is, each battery cell 11 can transmit electric energy to the unidirectional flyback power supply module 101 through the first switch module 110, and each battery cell 11 can receive electric energy from the unidirectional flyback power supply module 101 through the second switch module 120.

[0055] In this embodiment, the active balancing circuit 100 further includes a control module 130. The control module 130 is capable of obtaining N voltage values corresponding to the N battery cells 11. That is, the control module 130 is capable of continuously monitoring the voltage values of each of the N battery cells 11 and controlling the on / off states of the N first switch modules 110 and the N second switch modules 120 based on the N voltage values, thereby actively balancing the N battery cells 11. Since each battery cell 11 is connected to the unidirectional flyback power supply module 101 via a corresponding first switch module 110 and second switch module 120, the control module 130 is capable of controlling the first switch modules 110 and second switch modules 120 corresponding to any two battery cells 11, thereby actively balancing any two of the N battery cells 11.

[0056] Figure 3 FIG3 shows a third circuit topology diagram of an active balancing circuit provided in some embodiments of the present application, such as Figure 3 As shown, for example, the N battery cells 11 include cell1, cell2, cell3 and cell4, a total of 4 battery cells 11. After detecting that the voltage of cell4 is too low and the voltage of cell1 is too high, and the voltage difference of |cell1-cell4| triggers the set active equalization voltage difference start threshold, the first switch module 110 corresponding to cell1 is controlled to be turned on, and the second switch module 120 corresponding to cell1 remains turned off, and the second switch module 120 corresponding to cell4 is controlled to be turned on, and the first switch module corresponding to cell4 remains turned off, c The first switch module 110 and the second switch module 120 corresponding to cell 11 and cell 3 are both kept off. At this time, cell 1 is connected to the input end of the unidirectional flyback power supply module 101, forming a discharge circuit between cell 1 and the unidirectional flyback power supply module 101. Cell 4 is connected to the output end 52 of the unidirectional flyback power supply module 101, forming a charging circuit between the unidirectional flyback power supply module 101 and cell 4. Cell 2 discharges through the unidirectional flyback power supply module 101 and then charges cell 4, thereby actively balancing the power of cell 2 and cell 4.

[0057] In an embodiment of the present application, the input end 41 and the output end of each battery cell 11 in the battery module 10 are connected to the unidirectional flyback power supply module 101 through the first switch module 110 and the second switch module 120 respectively, and the control module 130 can control the on and off states of each first switch module 110 and the second switch module 120, so that the control module 130 can actively balance the power of each battery cell 11 in the battery module 10, thereby improving the active balancing effect between non-adjacent battery cells 11 and improving the convenience of active balancing between non-adjacent battery cells 11.

[0058] like Figure 1 and Figure 2 As shown, in some embodiments, optionally, the control module 130 includes: a sampling unit 131, the sampling end of the sampling unit 131 is connected to N battery cells 11, and the sampling unit 131 is used to collect N voltage values corresponding to the N battery cells 11; a first control unit 132, used to control the on-off state of the N first switch modules 110 according to the N voltage values; a second control unit 133, connected to the control end 33 of the N second switch modules 120, and the second control unit 133 is used to control the on-off state of the N second switch modules 120 according to the N voltage values; wherein the second control unit 133 is integrated with the sampling unit 131.

[0059] In the embodiment of the present application, the control module 130 includes a sampling unit 131, a first control unit 132, and a second control unit 133. The sampling unit 131 is connected to the N battery cells 11 and can collect the voltage value of each of the N battery cells 11, thereby monitoring the voltage values of all battery cells 11 in the battery module 10. The signal input terminals of the first control unit 132 and the second control unit 133 are connected to the signal output terminals of the sampling unit 131, that is, the N voltage values collected by the sampling unit 131 can be transmitted to the first control unit 132 and the second control unit 133. The signal output end of the first control unit 132 is connected to the control end 23 of the first switch module 110, that is, the first control unit 132 can transmit a control signal to the first switch module 110 to control the on-off state of the first switch module 110; the signal output end of the second control unit 133 is connected to the control end 33 of the second switch module 120, that is, the second control unit 133 can transmit a control signal to the control end 33 of the second switch module 120 to control the on-off state of the second switch module 120.

[0060] It should be noted that the sampling unit 131 and the second control unit 133 are integrated.

[0061] For example, the battery management system of the energy storage system includes an MCU (Microcontroller Unit) chip and an AFE (Analog Front-End) chip. The first control unit 132 is disposed within the MCU chip, and the sampling unit 131 and the second control unit 133 are integrated within the AFE chip. Specifically, the AFE chip is responsible for monitoring the voltage value of each battery cell 11 and transmitting the voltage value of each battery cell 11 to the MCU chip. The MCU chip is responsible for controlling the first switch module 110, and the AFE chip is responsible for controlling the second switch module 120, thereby achieving active balancing of each battery cell 11.

[0062] Exemplarily, the battery management system of the energy storage system includes an MCU chip, and the first control unit 132 , the second control unit 133 and the sampling unit 131 are all integrated in the MCU chip.

[0063] In an embodiment of the present application, the control module 130 includes a first control unit 132 and a second control unit 133 for controlling the first switch module 110 and the second switch module 120 respectively, and a sampling unit 131 for collecting the voltage value of each battery cell 11. The sampling unit 131 collects the voltage values of multiple battery cells 11, so that the control module 130 can flexibly control the active balancing of multiple battery cells 11, and the integrated arrangement of the sampling unit 131 and the second control unit 133 can further reduce the space occupied by the active balancing circuit 100 in the energy storage control system.

[0064] like Figure 1 and Figure 2 As shown, in some embodiments, optionally, the sampling unit 131 and the second control unit 133 are integrated into the front-end analog chip 134 ; and / or the first control unit 132 is set in the main control chip 135 .

[0065] In this embodiment, the sampling unit 131 and the second control unit 133 in the active balancing circuit 100 are integrated in the front-end analog chip 134, that is, the front-end analog chip 134 in the battery management system of the energy storage system serves as the sampling unit 131 and the second control unit 133 in the active balancing circuit 100.

[0066] Specifically, the front-end analog chip 134 is the AFE chip in the battery management system of the energy storage system. The AFE chip monitors the voltage value of each battery cell 11 through the sampling unit 131. The second control unit 133 in the AFE chip controls the on-off state of the second switch module 120 based on the detected voltage value of each battery cell 11.

[0067] In this embodiment, the first control unit 132 in the active balancing circuit 100 is disposed in the main control chip 135 , that is, the main control chip 135 in the battery management system of the energy storage system serves as the first control unit 132 .

[0068] Specifically, the main control chip 135 is the MCU chip in the battery management system of the energy storage system. The MCU chip is connected to the AFE chip. The AFE chip transmits the detected voltage values of each battery cell 11 to the MCU chip. The MCU chip can control the on and off state of the first switch module 110 based on the received voltage values of each battery cell 11.

[0069] In the embodiment of the present application, by using the main control chip 135 in the battery management system of the energy storage system as the first control unit 132 in the active balancing circuit 100, and using the front-end analog chip 134 in the battery management system of the energy storage system as the sampling unit 131 and the second control unit 133 in the active balancing circuit 100, there is no need to additionally provide an active balancing chip in the battery management system of the energy storage system, thereby reducing the dependence of the battery management system of the energy storage system on the procurement of active balancing chips, thereby reducing the production cost and maintenance cost of the battery management system of the energy storage system.

[0070] like Figure 1 and Figure 2 As shown, in some embodiments, optionally, the active balancing circuit 100 also includes: N isolated optocoupler modules 150, the input ends of the N isolated optocoupler modules 150 are all connected to the first control unit 132, and the output ends of the N isolated optocoupler modules 150 are respectively connected to the control ends 23 of the N first switch modules 110; a first power supply module 140, the output end of the first power supply module 140 is connected to the N isolated optocoupler modules 150, and the first power supply module 140 is used to power the N isolated optocoupler modules 150.

[0071] In this embodiment, the active balancing circuit 100 is further provided with N isolation optocoupler modules 150 and a first power supply module 140 for supplying power to the isolation optocoupler modules 150. Specifically, the N isolation optocoupler modules 150 are provided between the N first switch modules 110 and the first control unit 132 to provide digital isolation between the first control unit 132 and the first switch module 110.

[0072] It should be noted that the enable terminal of the first power supply module 140 is connected to the first control unit 132 , and the first control unit 132 can control whether the first power supply module 140 supplies power to the isolation optocoupler module 150 .

[0073] Exemplarily, the first power supply module 140 may be a unidirectional isolated fixed output power supply, and the first power supply module 140 is a direct current power supply.

[0074] For example, the first control unit 132 is provided on an MCU chip, and the first switch module 110 is selected as an NMOS transistor. When the first switch module 110 needs to be controlled to be in the on state, the MCU chip drives the EN (Enable) pin to output a high-level signal, which is transmitted to the light-emitting diode side of the isolation optocoupler module 150, turning on the optocoupler to output a high-level drive signal to the NMOS transistor, turning on the NMOS transistor.

[0075] In an embodiment of the present application, the isolation optocoupler module 150 isolates the first control unit 132 and the first switch module 110 without direct electrical connection by converting the electrical signal into an optical signal and then into an electrical signal, thereby avoiding damage to the first control unit 132 caused by the reverse electromotive force or drain voltage mutation generated at the moment of switching of the first switch module 110.

[0076] like Figure 1 and Figure 2 As shown, in some embodiments, optionally, the control module 130 also includes: N driving modules 160, the first ends of the N driving modules 160 are connected to the output end of the second control unit 133, the second ends of the N driving modules 160 are respectively connected to the control ends 33 of the N second switch modules 120, and the N driving modules 160 are used to output driving signals to the N second switch modules 120 respectively.

[0077] In an embodiment of the present application, the control module 130 also includes N driving modules 160, and the N driving modules 160 correspond one-to-one to the N second switch modules 120, and the driving module 160 is arranged between the output end of the second control unit 133 and the second switch module 120, so that the second control unit 133 can drive the on and off state of the second switch module 120 through the N driving modules 160.

[0078] Exemplarily, the driving module 160 includes a PMOS (P-channel Metal-Oxide-SemiconductorField-Effect Transistor) tube and a resistor, the second switching module 120 is an NMOS tube, the second control unit 133 is integrated in the AFE chip, the VS (VoltageSupply) pin of the AFE chip is connected to the gate of the PMOS tube and the first end of the resistor, the source of the PMOS tube is connected to the second end of the resistor, the drain of the PMOS tube is grounded, and the second end of the resistor is connected to the drain of the NMOS tube. Using PMOS as the driving module 160 can block the reverse transmission of the NMOS high voltage to the AFE chip, reducing the risk of breakdown, and the PMOS can also convert the low-voltage control signal output by the AFE chip into a high-level signal suitable for NMOS gate drive, ensuring the stability of the NMOS drive.

[0079] In an embodiment of the present application, by setting a driving module 160 in the second control unit 133, it is possible to prevent the reverse high voltage in the second switch module 120 from being transmitted to the second control unit 133, and it is also possible to convert the control signal output by the second control unit 133 into a corresponding level driving signal of the second switch module 120, thereby improving the operation of the second control unit 133 and the stability of the driving of the second switch module 120.

[0080] like Figure 1 and Figure 2 As shown, in some embodiments, optionally, the active balancing circuit 100 further includes: a second power supply module 170 connected to the power supply ends of the N second switch modules 120 , and the second power supply module 170 is used to supply power to the N second switch modules 120 .

[0081] In the embodiment of the present application, a second power supply module 170 is further provided in the active balancing circuit 100. The second power supply module 170 can supply power to the second switch module 120, so that the second control unit 133 can stably drive the second switch module 120 through the driving module 160, further improving the stability of the front-end analog chip 134 driving the second switch module 120 when the second control unit 133 is integrated in the front-end analog chip 134.

[0082] In some embodiments, optionally, the first switch module 110 includes: a first switch element 111, the first switch element 111 is arranged between the positive electrode of the battery cell 11 and the positive electrode of the input terminal 51 of the unidirectional flyback power supply module 101; a second switch element 112, the second switch element 112 is arranged between the negative electrode of the battery cell 11 and the negative electrode of the input terminal 51 of the unidirectional flyback power supply module 101;

[0083] The second switch module 120 includes: a third switch element 121, which is arranged between the positive pole of the battery cell 11 and the positive pole of the output terminal 52 of the unidirectional flyback power supply module 101; and a fourth switch element 122, which is arranged between the negative pole of the battery cell 11 and the negative pole of the output terminal 52 of the unidirectional flyback power supply module 101.

[0084] In this embodiment, each first switch module 110 includes a first switch element 111 and a second switch element 112, the first switch element 111 is connected between the positive pole of the battery cell 11 and the positive pole of the input terminal 51 of the unidirectional flyback power supply module 101, and the second switch element 112 is connected between the negative pole of the battery cell 11 and the negative pole of the input terminal 51 of the unidirectional flyback power supply module 101. Specifically, when controlling the battery cell 11 to transmit electric energy to the unidirectional flyback power supply module 101, it is necessary to control the first switch element 111 and the second switch element 112 in the corresponding first switch module 110 to be in the on state, so that the positive pole of the battery cell 11 is connected to the positive pole of the input terminal 51 of the unidirectional flyback power supply module 101, and the negative pole of the battery cell 11 is connected to the negative pole of the input terminal 51 of the unidirectional flyback power supply module 101, thereby forming a discharge circuit between the battery cell 11 and the unidirectional flyback power supply module 101, so that the battery cell 11 transmits electric energy to the unidirectional flyback power supply module 101 through the discharge circuit.

[0085] In this embodiment, each second switch element 112 includes a third switch element 121 and a fourth switch element 122, the third switch element 121 is connected between the positive pole of the battery cell 11 and the positive pole of the output terminal 52 of the unidirectional flyback power supply module 101, and the fourth switch element 122 is connected between the negative pole of the battery cell 11 and the negative pole of the output terminal 52 of the unidirectional flyback power supply module 101. Specifically, when controlling the unidirectional flyback power supply module 101 to transmit electric energy to the battery cell 11, it is necessary to control the third switch element 121 and the fourth switch element 122 in the corresponding second switch module 120 to be in the on state, so that the positive pole of the battery cell 11 is connected to the positive pole of the output terminal 52 of the unidirectional flyback power supply module 101, and the negative pole of the battery cell 11 is connected to the negative pole of the output terminal 52 of the unidirectional flyback power supply module 101, thereby forming a charging circuit between the battery cell 11 and the unidirectional flyback power supply, so that the battery cell 11 receives the electric energy output by the unidirectional flyback power supply module 101 through the charging circuit.

[0086] Exemplarily, the first switch element 111 , the second switch element 112 , the third switch element 121 and the fourth switch element 122 are all NMOS transistors.

[0087] In the embodiment of the present application, a first switch element 111 and a second switch element 112 respectively connected to the positive and negative poles of the battery cell 11 are provided in the first switch module 110, and a third switch element 121 and a fourth switch element 122 respectively connected to the positive and negative poles of the battery cell 11 are provided in the second switch module 120, so that a charging circuit is formed at the input end 41 of each battery cell 11 and a discharging circuit is formed at the output end 42 of each battery cell 11, thereby improving the stability of active balancing of the battery cells 11.

[0088] Figure 4 FIG4 shows a fourth circuit topology diagram of an active balancing circuit provided in some embodiments of the present application, such as Figure 4 As shown, the following describes the active balancing process by taking the second control unit and the sampling unit as the AFE chip in the battery management system of the energy storage system, the first control unit as the MCU chip in the battery management system of the energy storage system, the battery cells including cell1, cell2, cell3 and cell4, and the first switch module and the second switch module as NMOS switch matrices as an example:

[0089] The AFE chip collects the voltage values of cell1, cell2, cell3 and cell4 in real time, which are 2.5V, 3.0V, 3.5V and 3.0V respectively, and transmits the voltage values to the MCU chip in real time; the MCU chip monitors that the voltage value of cell1 (2.5V) is lower than the second voltage threshold, and the voltage value of cell3 is higher than the first voltage threshold, that is, the voltage of cell1 is too low and the voltage of cell3 is too high, and the voltage difference between cell1 and cell3 is greater than the first difference threshold, then active balancing between cell1 and cell3 is started.

[0090] The MCU chip drives the EN3 pin to output a high-level 3.3V drive signal, which is transmitted to the light-emitting diode side of the isolation optocoupler module. The collector and emitter of the isolation optocoupler module are turned on, and the emitter side outputs a high-level 5V drive signal, which is transmitted to the NMOS switch matrix at the output end of cell3 and turned on, so that cell3 is connected to the input side of the unidirectional flyback power supply module. At this time, cell3 discharges to the unidirectional flyback power supply module.

[0091] The MCU chip notifies the AFE chip to set the gate-source of the NMOS inside the AFE chip to a high level of 3.3V, driving the drain-source of NMOS2 to close. The voltage across the resistor R is 1.5V, that is, the source-gate voltage of PMOS2 is 1.5V, driving its source-drain to be turned on and closed. Then, the VC2 pin of the AFE chip outputs a high-level drive signal, driving the NMOS matrix switch on the input side of the AFE chip of cell1 to turn on. Cell1 is connected to the output side of the unidirectional flyback power supply module 101. At this time, cell1 receives the power output by the unidirectional flyback power supply module.

[0092] At this time, the cell3 battery is discharged through the unidirectional flyback power supply module, and the cell1 battery is charged through the unidirectional flyback power supply module, performing active balancing between cell1 and cell3.

[0093] When the AFE chip detects the voltage difference between cell1 and cell3, it triggers the second difference threshold for active balancing to be turned off. The second difference threshold is 0.1V. The AFE chip sets the gate-source of the internal NMOS to 0V, and there is no voltage divider across the resistor R, that is, the source-gate of PMOS2 is 0V. Then the AFE chip drives the NMOS matrix switch on the AFE side input side of the cell1 battery to be disconnected, and the MCU drives the EN3 pin to output a low level of 0V to drive the NMOS switch matrix at the output end of cell3 to be disconnected.

[0094] At this point, the active balancing process ends.

[0095] According to one embodiment of the present application, Figure 5 FIG. 1 shows a flow chart of an active balancing method provided in some embodiments of the present application, such as Figure 5 As shown, an active balancing method is proposed, which is applied to the active balancing circuit in any of the above embodiments. The active balancing method includes:

[0096] Step 502, obtaining N voltage values corresponding to N battery cells;

[0097] Wherein, N is an integer greater than 1.

[0098] In this embodiment, the sampling unit in the active balancing circuit can collect N voltage values corresponding to N battery cells, and based on the N voltage values, it can be determined whether the active balancing mode needs to be turned on to actively balance the voltages of the two battery cells.

[0099] Step 504 , controlling a first target switch module among the N first switch modules to be turned on, and controlling a second target switch module among the N second switch modules to be turned on, based on the N voltage values, to actively discharge the first battery cell and actively charge the second battery cell among the N battery cells;

[0100] The first target switch module is connected to the first battery cell, the second target switch module is connected to the second battery cell, and the voltage value of the first battery cell is greater than the voltage value of the second battery cell.

[0101] In this embodiment, the active balancing circuit includes a switch module array disposed at the output ends of N battery cells and a switch module array disposed at the input ends of N battery cells. The switch module array disposed at the output ends of the N battery cells includes N first switch modules, which are connected between a unidirectional flyback power supply module and the output ends of the battery cells. By controlling the on / off states of the N first switch modules, the on / off state between the output ends of the battery cells and the unidirectional flyback power supply module can be controlled. That is, when the first switch modules are turned on, the corresponding battery cells can be actively discharged to the unidirectional flyback power supply module through the first switch modules. The switch module array disposed at the input ends of the N battery cells includes N second switch modules, which are connected between the unidirectional flyback power supply module and the input ends of the battery cells. By controlling the on / off states of the N second switch modules, the on / off state between the input ends of the battery cells and the unidirectional flyback power supply module can be controlled. That is, when the second switch modules are turned on, the unidirectional flyback power supply module can actively charge the corresponding battery cells.

[0102] Specifically, based on the N voltage values, it is possible to determine the first battery cell with an excessively high voltage and the second battery cell with an excessively low voltage among the N battery cells, and determine that the first battery cell needs to be discharged and the second battery cell needs to be charged. Since the first switch module is used to discharge the battery cells, the first switch module corresponding to the first battery cell is determined as the first target switch module, and the first target switch module is driven to conduct to transfer the electrical energy of the first battery cell to the unidirectional flyback power supply module. Since the second switch module is used to charge the battery cells, the second switch module corresponding to the second battery cell is determined as the second target switch module, and the second target switch module is driven to conduct to transfer the electrical energy at the unidirectional flyback power supply module to the second battery cell.

[0103] In an embodiment of the present application, the input and output ends of each battery cell in the battery pack are connected to a unidirectional flyback power supply module through a first switch module and a second switch module respectively, and the control module can control the on and off states of each first switch module and the second switch module, actively discharge the first battery cell with a higher voltage, and actively charge the second battery cell with a lower voltage, so that the control module can actively balance each battery cell in the battery pack, thereby improving the active balancing effect between non-adjacent battery cells and improving the convenience of active balancing between non-adjacent battery cells.

[0104] In some embodiments, optionally, before controlling a first target switch module among the N first switch modules to be turned on and controlling a second target switch module among the N second switch modules to be turned on according to the N voltage values, the active balancing method further includes:

[0105] According to the first voltage threshold and the second voltage threshold, the first battery cell and the second battery cell among N battery cells are determined, and the first voltage threshold is greater than the second voltage threshold; wherein, the voltage value of the first battery cell is greater than the first voltage threshold, the voltage value of the second battery cell is less than the second voltage threshold, and the voltage difference between the voltage value of the first battery cell and the voltage value of the second battery cell is greater than the first difference threshold.

[0106] In this embodiment, before starting the active balancing process, it is necessary to determine the first battery cell with an excessively high voltage and the second battery cell with an excessively low voltage among the N battery cells. Specifically, by setting a first voltage threshold and a second voltage threshold, and comparing the collected voltage values of the battery cells with the first voltage threshold and the second voltage threshold respectively, the battery cell whose voltage value is greater than the first voltage threshold is taken as the first battery cell, and the battery cell whose voltage value is less than the second voltage threshold is taken as the second battery cell, thereby screening out the first battery cell and the second battery cell from the multiple battery cells, and when the voltage difference between the voltage value of the first battery cell and the voltage value of the second battery cell is greater than the first difference threshold, it is determined that the first battery cell and the second battery cell need to be actively balanced.

[0107] It should be noted that the value ranges of the first voltage threshold and the second voltage threshold are related to the voltage value of the battery cell, and the first voltage threshold and the second voltage threshold can be floating thresholds, and the specific values are not specifically limited.

[0108] In an embodiment of the present application, by setting a first voltage threshold and a second voltage threshold, and comparing the collected voltage values of the battery cells with the first voltage threshold and the second voltage threshold respectively, the first battery cell with an excessively large voltage value and the second battery cell with an excessively small voltage value can be screened out, thereby improving the stability of active balancing of multiple battery cells in the battery pack.

[0109] In some embodiments, optionally, after controlling a first target switch module among the N first switch modules to be turned on and controlling a second target switch module among the N second switch modules to be turned on according to the N voltage values, the active balancing method further includes:

[0110] Monitor the voltage difference between the voltage value of the first battery cell and the voltage value of the second battery cell; when the voltage difference is less than a second difference threshold, control the first target switch module and the second target switch module to be disconnected.

[0111] In this embodiment, during the process of actively balancing the first and second battery cells, the voltage values of the first and second battery cells are continuously monitored, and a voltage difference between the voltage values of the first and second battery cells is determined, where the voltage difference is the absolute value of the difference between the two voltage values. If it is detected that the voltage difference is less than a second difference threshold, it is determined that the voltage difference between the first and second battery cells is small, i.e., the active balancing process between the battery cells has been completed, and the first target switch module and the second target switch module can be controlled to disconnect.

[0112] Exemplarily, the second difference threshold is smaller than the first difference threshold.

[0113] In an embodiment of the present application, during the active balancing process, the voltage difference between the voltage value of the first battery cell and the voltage value of the second battery cell is continuously monitored, and when the voltage difference is less than the second difference threshold, it is determined that the active balancing process has been completed, and the first target switch module and the second target switch module are disconnected at this time, thereby improving the accuracy and stability of the control of the active balancing process.

[0114] In some embodiments, optionally, the number of the first battery cells is at least two, and the number of the second battery cells is the same as the number of the first battery cells.

[0115] In an embodiment of the present application, the number of first battery cells performing active balancing can be multiple, and the number of second battery cells corresponds one-to-one to the first battery cells, so that each battery cell in the battery pack can be actively balanced, thereby improving the voltage consistency between each battery cell in the battery pack.

[0116] Specifically, when the number of the first battery cells and the number of the second battery cells are at least two, active balancing may be performed on each pair of the first battery cells and the second battery cells in sequence.

[0117] According to one embodiment of the present application, Figure 6 FIG. 1 shows one of the structural block diagrams of an active equalization device provided in some embodiments of the present application. Figure 6 As shown, an active balancing device 600 is proposed, which is applied to the active balancing circuit in any of the above embodiments. The active balancing device 600 includes:

[0118] An acquisition module 602 is configured to acquire N voltage values corresponding to N battery cells, where N is an integer greater than 1;

[0119] a control module 604 configured to control a first target switch module among the N first switch modules to be turned on, and to control a second target switch module among the N second switch modules to be turned on, so as to actively discharge the first battery cell and actively charge the second battery cell among the N battery cells;

[0120] The first target switch module is connected to the first battery cell, the second target switch module is connected to the second battery cell, and the voltage value of the first battery cell is greater than the voltage value of the second battery cell.

[0121] In an embodiment of the present application, the input and output ends of each battery cell in the battery pack are connected to a unidirectional flyback power supply module through a first switch module and a second switch module respectively, and the control module can control the on and off states of each first switch module and the second switch module, actively discharge the first battery cell with a higher voltage, and actively charge the second battery cell with a lower voltage, so that the control module can actively balance each battery cell in the battery pack, thereby improving the active balancing effect between non-adjacent battery cells and improving the convenience of active balancing between non-adjacent battery cells.

[0122] In some embodiments, optionally, the active balancing device 600 further includes:

[0123] a determination module, configured to determine, based on a first voltage threshold and a second voltage threshold, a first battery cell and a second battery cell among the N battery cells, wherein the first voltage threshold is greater than the second voltage threshold;

[0124] The voltage value of the first battery cell is greater than the first voltage threshold, the voltage value of the second battery cell is less than the second voltage threshold, and the voltage difference between the voltage value of the first battery cell and the voltage value of the second battery cell is greater than the first difference threshold.

[0125] In an embodiment of the present application, by setting a first voltage threshold and a second voltage threshold, and comparing the collected voltage values of the battery cells with the first voltage threshold and the second voltage threshold respectively, the first battery cell with an excessively large voltage value and the second battery cell with an excessively small voltage value can be screened out, thereby improving the stability of active balancing of multiple battery cells in the battery pack.

[0126] In some embodiments, optionally, the active balancing device 600 further includes:

[0127] A monitoring module, configured to monitor a voltage difference between a voltage value of the first battery cell and a voltage value of the second battery cell;

[0128] The control module 604 is configured to control the first target switch module and the second target switch module to be disconnected when the voltage difference is less than a second difference threshold.

[0129] In an embodiment of the present application, during the active balancing process, the voltage difference between the voltage value of the first battery cell and the voltage value of the second battery cell is continuously monitored, and when the voltage difference is less than the second difference threshold, it is determined that the active balancing process has been completed, and the first target switch module and the second target switch module are disconnected at this time, thereby improving the accuracy and stability of the control of the active balancing process.

[0130] According to one embodiment of the present application, Figure 7 FIG2 shows a second structural block diagram of an active balancing device provided in some embodiments of the present application. Figure 7 As shown, active balancing device 700 includes a processor 702 and a memory 704. Memory 704 stores a program or instruction that, when executed by processor 702, implements the steps of the active balancing method described in any of the above-described embodiments. Therefore, active balancing device 700 has all the benefits of the active balancing method described in any of the above-described embodiments, and no further details are given here.

[0131] According to one embodiment of the present application, optionally, a readable storage medium is provided, on which a program or instruction is stored. When the program or instruction is executed by a processor, the steps of the active balancing method in any of the above embodiments are implemented, thereby having all the beneficial technical effects of the active balancing method in any of the above embodiments.

[0132] The readable storage medium includes a read-only memory (ROM), a random access memory (RAM), a magnetic disk, or an optical disk.

[0133] A computer-readable storage medium can be a tangible device that can retain and store instructions for use by an instruction execution device. A computer-readable storage medium can be, but is not limited to, an electronic storage device, a magnetic storage device, an optical storage device, an electromagnetic storage device, a semiconductor storage device, or any suitable combination of the foregoing. A non-exhaustive list of more specific examples of computer-readable storage media includes: a portable computer floppy disk, a hard disk, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), static random access memory (SRAM), a portable compact disc read-only memory (CD-ROM), a digital versatile disk (DVD), a memory card, a floppy disk, an encoding mechanical device (such as a punched card or a groove with a raised structure on which instructions are recorded), and any suitable combination of the foregoing. As used herein, a computer-readable storage medium should not be understood as a transmission signal per se, such as radio waves or other freely propagating electromagnetic waves, electromagnetic waves propagating through a waveguide or other transmission medium, or electrical signals transmitted through wires.

[0134] According to one embodiment of the present application, Figure 8 A structural block diagram of an energy storage system is shown in some embodiments of the present application. Figure 8As shown, the energy storage system 800 includes: a battery module 10, the battery module 10 includes a plurality of battery cells 11, and a battery management system 802, the battery management system 802 includes the active balancing circuit 100 in any of the above embodiments, and actively balances the charge of the plurality of battery cells in the battery module 10 based on the active balancing circuit; and / or executes the active balancing method in any of the above embodiments, thereby having the active balancing circuit 100 in any of the above embodiments; and / or all the beneficial technical effects of the active balancing method in any of the above embodiments, which are not repeated here.

[0135] It should be clarified that in the claims, specification and drawings of this application, the term "plurality" refers to two or more. Unless otherwise clearly defined, the orientation or positional relationship indicated by the terms "upper" and "lower" is based on the orientation or positional relationship shown in the drawings. It is only for the purpose of more conveniently describing this application and making the description process simpler, and is not intended to indicate or imply that the device or element referred to must have the specific orientation described, be constructed and operated in a specific orientation. Therefore, these descriptions cannot be understood as limitations on this application. The terms "connect", "install", "fix" and the like should be understood in a broad sense. For example, "connection" can be a fixed connection between multiple objects, or a detachable connection between multiple objects, or an integral connection; it can be a direct connection between multiple objects, or an indirect connection between multiple objects through an intermediate medium. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood based on the specific circumstances of the above data.

[0136] In the claims, specification, and drawings of this application, the terms "one embodiment," "some embodiments," "a specific embodiment," and the like mean that the specific features, structures, materials, or characteristics described in conjunction with that embodiment or example are included in at least one embodiment or example of this application. In the claims, specification, and drawings of this application, schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

[0137] The above are merely preferred embodiments of the present application and are not intended to limit the present application. Those skilled in the art will readily appreciate that various modifications and variations are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present application shall be included within the scope of protection of the present application.

Claims

1. An active equalization circuit, characterized in that: Applied to an energy storage system, the energy storage system includes a battery module, the battery module includes: N battery cells, N is an integer greater than 1, the active balancing circuit includes: Unidirectional flyback power supply module; N first switch modules, wherein a first end of each of the N first switch modules is connected to the input end of the unidirectional flyback power supply module, and a second end of each of the N first switch modules is connected to the output end of the N battery cells; N second switch modules, wherein a first end of each of the N second switch modules is connected to the output end of the unidirectional flyback power supply module, and a second end of each of the N second switch modules is connected to the input end of the N battery cells; A control module is connected to the control ends of the N first switch modules and the control ends of the N second switch modules, wherein the control module is used to control the on and off states of the N first switch modules and the N second switch modules according to the N voltage values corresponding to the N battery cells, so as to actively balance the power of the N battery cells.

2. The active equalization circuit according to claim 1, wherein: The control module includes: A sampling unit, wherein a sampling end of the sampling unit is connected to the N battery cells, and the sampling unit is used to collect N voltage values corresponding to the N battery cells; a first control unit, configured to control the on / off states of the N first switch modules according to the N voltage values; a second control unit connected to the control ends of the N second switch modules, and configured to control the on / off states of the N second switch modules according to the N voltage values; Wherein, the second control unit is integrated with the sampling unit.

3. The active equalization circuit according to claim 2, characterized in that: The sampling unit and the second control unit are integrated into a front-end analog chip; and / or The first control unit is arranged in the main control chip.

4. The active equalization circuit according to claim 2, wherein: Also includes: N isolated optocoupler modules, wherein input ends of the N isolated optocoupler modules are all connected to the first control unit, and output ends of the N isolated optocoupler modules are respectively connected to control ends of the N first switch modules; A first power supply module, wherein an output end of the first power supply module is connected to the N isolated optocoupler modules, and the first power supply module is used to supply power to the N isolated optocoupler modules.

5. The active equalization circuit according to claim 2, wherein: The control module further includes: N driving modules, the first ends of the N driving modules are connected to the output end of the second control unit, the second ends of the N driving modules are respectively connected to the control ends of the N second switch modules, and the N driving modules are used to output driving signals to the N second switch modules respectively.

6. The active equalization circuit according to claim 5, characterized in that: Also includes: The second power supply module is connected to the power supply ends of the N second switch modules, and the second power supply module is used to supply power to the N second switch modules.

7. The active equalization circuit according to any one of claims 1 to 6, characterized in that: The first switch module includes: a first switch element, the first switch element being arranged between the positive electrode of the battery cell and the positive electrode of the input end of the unidirectional flyback power supply module; a second switch element, the second switch element being arranged between the negative electrode of the battery cell and the negative electrode of the input terminal of the unidirectional flyback power supply module; The second switch module includes: a third switch element, the third switch element being arranged between the positive electrode of the battery cell and the positive electrode of the output end of the unidirectional flyback power supply module; A fourth switch element is provided between the negative electrode of the battery cell and the negative electrode of the output end of the unidirectional flyback power supply module.

8. An active balancing method, characterized in that: The active balancing circuit according to any one of claims 1 to 7, wherein the active balancing method comprises: Get N voltage values corresponding to N battery cells, where N is an integer greater than 1; According to the N voltage values, controlling a first target switch module among the N first switch modules to be turned on, and controlling a second target switch module among the N second switch modules to be turned on, so as to actively discharge the first battery cell and actively charge the second battery cell among the N battery cells; The first target switch module is connected to the first battery cell, the second target switch module is connected to the second battery cell, and the voltage value of the first battery cell is greater than the voltage value of the second battery cell.

9. The active equalization method according to claim 8, characterized in that: Before controlling the first target switch module among the N first switch modules to be turned on and controlling the second target switch module among the N second switch modules to be turned on according to the N voltage values, the active balancing method further includes: Determine the first battery cell and the second battery cell among the N battery cells according to a first voltage threshold and a second voltage threshold, wherein the first voltage threshold is greater than the second voltage threshold; The voltage value of the first battery cell is greater than the first voltage threshold, the voltage value of the second battery cell is less than the second voltage threshold, and the voltage difference between the voltage value of the first battery cell and the voltage value of the second battery cell is greater than the first difference threshold.

10. The active equalization method according to claim 8, characterized in that: After controlling a first target switch module among the N first switch modules to be turned on and controlling a second target switch module among the N second switch modules to be turned on according to the N voltage values, the active balancing method further includes: monitoring a voltage difference between a voltage value of the first battery cell and a voltage value of the second battery cell; When the voltage difference is less than a second difference threshold, the first target switch module and the second target switch module are controlled to be disconnected.

11. The active balancing method according to any one of claims 8 to 10, characterized in that: The number of the first battery cells is at least two, and the number of the second battery cells is the same as the number of the first battery cells.

12. An active balancing device, characterized in that: The active equalization circuit according to any one of claims 1 to 7, wherein the active equalization device comprises: An acquisition module is used to obtain N voltage values corresponding to N battery cells, where N is an integer greater than 1; a control module, configured to control a first target switch module among the N first switch modules to be turned on, and to control a second target switch module among the N second switch modules to be turned on, so as to actively discharge the first battery cell and actively charge the second battery cell among the N battery cells; The first target switch module is connected to the first battery cell, the second target switch module is connected to the second battery cell, and the voltage value of the first battery cell is greater than the voltage value of the second battery cell.

13. An energy storage system, characterized in that: include: A battery module, including multiple battery cells; A battery management system comprising the active balancing circuit according to any one of claims 1 to 7, wherein the active balancing circuit is used to actively balance the charge of the plurality of cells in the battery module; and / or Execute the active equalization method according to any one of claims 8 to 11.

Images