Battery active balancing circuit and battery system

Abstract

The application relates to a battery active balancing circuit and a battery system, wherein the balancing circuit is connected with a battery pack to be tested through a balancing control loop; a direct-current conversion module is connected with the balancing control loop; a battery voltage detection circuit is connected with the balancing control loop; a control module is connected with the balancing control loop, the direct-current conversion module and the battery voltage detection circuit; the control module acquires a maximum voltage signal and a minimum voltage signal in each single battery, controls the balancing control loop to connect the single battery corresponding to the maximum voltage signal and the single battery corresponding to the minimum voltage signal when the maximum voltage signal and the minimum voltage signal meet a preset voltage condition, and controls the direct-current conversion module to supply power from the single battery corresponding to the maximum voltage to the single battery corresponding to the minimum voltage, so that only one power conversion efficiency loss is generated, time interval loss is avoided, the efficiency of the battery active balancing is improved, and the battery active balancing speed is improved.

Description

Technical Field

[0001] This application relates to the field of battery technology, and in particular to a battery active balancing circuit and battery system. Background Technology

[0002] Due to their chemical and physical characteristics, the voltage of a single rechargeable battery cell is relatively low. For example, the voltage of a single lead-acid and nickel-metal hydride battery is 1.2V, that of a lithium iron phosphate battery is 3.2V, that of a lithium manganese oxide and ternary lithium battery is 3.7V, and that of a sodium hydroxide and solid-state battery is below 5V. To obtain greater power, rechargeable batteries are connected in series to form a battery pack. Connecting multiple cells in series requires battery pairing; only cells with the same parameters can be placed in the same battery pack. While each cell in a battery pack has consistent characteristics during manufacturing, the actual usage conditions vary, causing changes in battery characteristics over long-term use. Therefore, battery packs need to incorporate balancing circuits to dynamically adjust the characteristics of each rechargeable battery cell throughout the charging and discharging process, ensuring consistent performance across all cells.

[0003] Equalization circuits are divided into passive equalization circuits and active equalization circuits. Passive equalization circuits are the simplest. During charging, if any cell's voltage is found to be higher than the others, this cell is connected to the equalization circuit. A resistor is connected in parallel to the equalization circuit; the resistor generates heat and dissipates the excess charge, maintaining equal voltage across all cells and ensuring the entire battery pack is fully charged. However, this circuit cannot achieve equalization during battery discharge. Active equalization circuits transfer the voltage of higher-voltage cells to lower-voltage cells. Common active equalization circuits include adjacent-cell charge transfer circuits, capacitor-based equalization circuits, system power equalization circuits, and transformer equalization circuits.

[0004] During the implementation process, the inventors discovered at least the following problems in the traditional technology: the existing active battery balancing method has low balancing efficiency and slow balancing speed. Utility Model Content

[0005] Therefore, it is necessary to address the problems existing in the above-mentioned active battery balancing methods by providing an active battery balancing circuit and battery system that can generate only one power conversion efficiency loss, with high balancing efficiency and fast balancing speed.

[0006] To achieve the above objectives, this utility model provides a battery active balancing circuit, including:

[0007] The equalization control loop is connected to the battery pack under test; the battery pack under test includes multiple individual cells, which are connected in series.

[0008] DC-DC conversion module, the DC-DC conversion module is connected to the equalization control loop;

[0009] Battery voltage detection circuit, which is connected to the equalization control loop;

[0010] The control module is connected to the equalization control loop, the DC-DC conversion module, and the battery voltage detection circuit. The control module is configured to acquire the maximum and minimum voltage signals of each individual battery cell. When the maximum and minimum voltage signals meet the preset voltage conditions, the equalization control loop is controlled to connect the individual battery cell with the maximum voltage signal and the individual battery cell with the minimum voltage signal, and the DC-DC conversion module is controlled to replenish power from the individual battery cell with the maximum voltage signal to the individual battery cell with the minimum voltage signal.

[0011] In one embodiment, the equalization control loop includes a discharge loop and a charging loop;

[0012] The discharge circuit is connected to the DC-DC conversion module, the control module, and each individual battery cell; the charging circuit is connected to the DC-DC conversion module, the control module, and each individual battery cell.

[0013] The control module is also configured to control the discharge circuit to connect to the single cell corresponding to the maximum voltage signal and the charging circuit to connect to the single cell corresponding to the minimum voltage signal when the maximum voltage signal and the minimum voltage signal meet preset voltage conditions.

[0014] In one embodiment, the discharge circuit includes a first battery selection module and a first rectifier bridge commutation module; the charging circuit includes a second battery selection module and a second rectifier bridge commutation module.

[0015] The first battery selection module is connected to the control module and each individual battery cell respectively; the first rectifier bridge commutation module is connected to the DC-DC conversion module and each individual battery cell respectively.

[0016] The second battery selection module is connected to the control module and each individual battery cell respectively; the second rectifier bridge commutation module is connected to the DC-DC conversion module and each individual battery cell respectively.

[0017] In one embodiment, the discharge circuit further includes a plurality of first bidirectional switching transistor modules; the first battery selection module includes a plurality of first battery selection modules; the charging circuit further includes a plurality of second bidirectional switching transistor modules; and the second battery selection module includes a plurality of second battery selection modules.

[0018] The negative terminal of a single battery is connected to the first terminal of the corresponding first bidirectional switching transistor module, and the positive terminal of a single battery is connected to the first terminal of another corresponding first bidirectional switching transistor module; the second terminal of each first bidirectional switching transistor module is connected to the first rectifier bridge commutation module, the control terminal of the first bidirectional switching transistor module is connected to the corresponding first battery selection module, and each first battery selection module is connected to the control module.

[0019] The negative terminal of a single battery is connected to the first terminal of the corresponding second bidirectional switching transistor module, and the positive terminal of a single battery is connected to the first terminal of another corresponding second bidirectional switching transistor module; the second terminal of each second bidirectional switching transistor module is connected to the second rectifier bridge commutation module, the control terminal of the second bidirectional switching transistor module is connected to the corresponding second battery selection module, and each second battery selection module is connected to the control module.

[0020] In one embodiment, the first battery selection module includes a first coupling isolator, a first resistor, and a first bidirectional diode; the second battery selection module includes a second coupling isolator, a second resistor, and a second bidirectional diode.

[0021] The first end of the first coupling isolator is connected to the first power supply; the second end of the first coupling isolator is connected to the first end of the first resistor; the second end of the first resistor is connected to the first end of the first bidirectional diode; the second end of the first bidirectional diode is connected to another first battery selection module corresponding to the positive terminal of the same single cell; the third end of the first coupling isolator is connected to the second power supply; and the fourth end of the first coupling isolator is connected to the control terminal of the first bidirectional switching module corresponding to the negative terminal of the same single cell.

[0022] The first end of the second coupling isolator is connected to the first power supply; the second end of the second coupling isolator is connected to the first end of the second resistor; the second end of the second resistor is connected to the first end of the second bidirectional diode; the second end of the second bidirectional diode is connected to another second battery selection module corresponding to the positive terminal of the same single cell; the third end of the second coupling isolator is connected to the fifth power supply; and the fourth end of the second coupling isolator is connected to the control terminal of the second bidirectional switching module corresponding to the negative terminal of the same single cell.

[0023] In one embodiment, the first battery selection module includes a plurality of first electronic switches and a third bidirectional diode; the second battery selection module includes a plurality of second electronic switches and a fourth bidirectional diode.

[0024] The negative terminal of a single battery cell is connected to the first terminal of the corresponding first electronic switch, and the positive terminal of the single battery cell is connected to the first terminal of another corresponding first electronic switch; the second terminal of each first electronic switch is connected to the first rectifier bridge commutation module, the control terminal of the first electronic switch is connected to the first terminal of the corresponding third bidirectional diode, the second terminal of the third bidirectional diode is connected to another first battery selection module corresponding to the positive terminal of the same single battery cell; the control terminal of the second terminal of the third bidirectional diode is connected to the control module, and the power supply terminal of the first electronic switch is connected to the seventh power supply.

[0025] The negative terminal of a single battery cell is connected to the first terminal of the corresponding second electronic switch, and the positive terminal of a single battery cell is connected to the first terminal of another corresponding second electronic switch; the second terminal of each second electronic switch is connected to the second rectifier bridge commutation module, the control terminal of the second electronic switch is connected to the first terminal of the corresponding fourth bidirectional diode, the second terminal of the fourth bidirectional diode is connected to another second battery selection module corresponding to the positive terminal of the same single battery cell; the control terminal of the second terminal of the fourth bidirectional diode is connected to the control module, and the power supply terminal of the second electronic switch is connected to the seventh power supply.

[0026] In one embodiment, the battery active balancing circuit further includes a discharge-assisted isolation power supply and a charging-assisted isolation power supply;

[0027] The discharge-assisted isolation power supply is connected to the discharge circuit; the charging-assisted isolation power supply is connected to the charging circuit.

[0028] In one embodiment, the battery active balancing circuit further includes a discharge selection decoding circuit and a charge selection decoding circuit;

[0029] The discharge selection decoding circuit is connected between the discharge circuit and the control module; the charge selection decoding circuit is connected between the charging circuit and the control module.

[0030] In one embodiment, the DC-DC converter module includes a DC-DC chip and an eleventh coupling isolator;

[0031] The input of the eleventh coupling isolator is connected to the control module, and the output of the eleventh coupling isolator is connected to the DC-DC chip. The DC-DC chip is connected to the equalization control loop.

[0032] In one embodiment, the battery active balancing circuit further includes a communication interface circuit; the communication interface circuit is connected to the control module and is used to connect to the battery management system.

[0033] On the other hand, this utility model also provides a battery system, including a battery pack under test, a battery management system, and a battery active balancing circuit as described in any of the above.

[0034] The battery management system is connected to the battery pack under test, and the active battery balancing circuit is connected to both the battery pack under test and the battery management system.

[0035] One of the above technical solutions has the following advantages and beneficial effects:

[0036] In each embodiment of the above-described active battery balancing circuit, an balancing control loop, a DC-DC conversion module, a battery voltage detection circuit, and a control module are included. The balancing control loop is connected to the battery pack under test. The battery pack under test includes multiple individual cells connected in series. The DC-DC conversion module is connected to the balancing control loop. The battery voltage detection circuit is connected to the balancing control loop. The control module is connected to the balancing control loop, the DC-DC conversion module, and the battery voltage detection circuit, respectively. The control module is configured to acquire the maximum voltage signal and the minimum voltage signal of each individual cell. When the maximum voltage signal and the minimum voltage signal meet a preset voltage condition, the control module controls the balancing control loop to connect the individual cell with the maximum voltage signal and the individual cell with the minimum voltage signal, and controls the DC-DC conversion module to replenish power from the individual cell with the maximum voltage to the individual cell with the minimum voltage, thereby achieving efficient and rapid active balancing adjustment of the battery pack under test. This application uses a battery voltage detection circuit to detect the voltage of each individual battery cell. Based on the maximum and minimum voltage signals of each individual battery cell, the control module controls the equalization control circuit to operate. This connects the individual battery cell with the maximum voltage signal and the individual battery cell with the minimum voltage signal, and controls the DC-DC conversion module to operate. This enables charging from the individual battery cell with the maximum voltage to the individual battery cell with the minimum voltage, resulting in only one power conversion efficiency loss and avoiding time interval losses. This improves the efficiency and speed of active battery equalization. Attached Figure Description

[0037] Figure 1 This is a schematic diagram of the battery active balancing circuit in one embodiment;

[0038] Figure 2 This is a schematic diagram of the first circuit of the discharge circuit in one embodiment;

[0039] Figure 3 This is a schematic diagram of the first circuit of the charging circuit in one embodiment;

[0040] Figure 4 This is a schematic diagram of the second circuit of the discharge circuit in one embodiment;

[0041] Figure 5 This is a schematic diagram of the second circuit of the charging circuit in one embodiment;

[0042] Figure 6 This is a circuit diagram of an auxiliary isolation power supply in one embodiment;

[0043] Figure 7This is a circuit diagram of a discharge selection decoding circuit in one embodiment;

[0044] Figure 8 A circuit diagram of a charging selection decoding circuit in one embodiment;

[0045] Figure 9 This is a circuit diagram of a DC-DC conversion module in one embodiment;

[0046] Figure 10 This is a circuit diagram of the communication interface circuit in one embodiment;

[0047] Figure 11 This is a circuit diagram of the control module in one embodiment;

[0048] Figure 12 This is a circuit diagram of a battery voltage detection circuit in one embodiment.

[0049] Figure label:

[0050] 10. Equalization control circuit; 110. Discharge circuit; 112. First battery selection module; 114. First battery selection module; 116. First rectifier bridge commutation module; 118. First bidirectional switch module; 120. Charging circuit; 122. Second battery selection module; 124. Second battery selection module; 126. Second rectifier bridge commutation module; 128. Second bidirectional switch module; 20. DC-DC conversion module; 30. Battery voltage detection circuit; 40. Control module; 510. Discharge auxiliary isolation power supply; 520. Charging auxiliary isolation power supply; 610. Discharge selection decoding circuit; 620. Charging selection decoding circuit; 70. Communication interface circuit; 80. Battery pack under test; 810. Individual battery cell;

[0051] OP1, First coupling isolator; OP2, Second coupling isolator; OP11, Eleventh coupling isolator; D1, First bidirectional diode; D2, Second bidirectional diode; D3, Third bidirectional diode; D4, Fourth bidirectional diode; R1, First resistor; R2, Second resistor; S1, First electronic switch; S2, Second electronic switch; P1, DC-DC chip. Detailed Implementation

[0052] To enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present application, and not all embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative effort should fall within the scope of protection of the present application.

[0053] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate for the embodiments of this application described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0054] In this application, the terms "upper," "lower," "left," "right," "front," "rear," "top," "bottom," "inner," "outer," "middle," "vertical," "horizontal," "lateral," and "longitudinal" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. These terms are primarily for the purpose of better describing this application and its embodiments, and are not intended to limit the indicated device, element, or component to having a specific orientation, or to be constructed and operated in a specific orientation.

[0055] Furthermore, in addition to indicating location or positional relationship, some of the aforementioned terms may also have other meanings. For example, the term "above" may also be used in some cases to indicate a certain dependency or connection relationship. Those skilled in the art can understand the specific meaning of these terms in this application based on the specific circumstances.

[0056] In addition, the term "multiple" should mean two or more.

[0057] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. This application will now be described in detail with reference to the accompanying drawings and embodiments.

[0058] In one embodiment, such as Figure 1As shown, a battery active balancing circuit is provided, including a balancing control loop 10, a DC-DC conversion module 20, a battery voltage detection circuit 30, and a control module 40. The balancing control loop 10 is connected to a battery pack 80 under test. The battery pack 80 under test includes multiple individual cells 810 connected in series. The DC-DC conversion module 20 is connected to the balancing control loop 10. The battery voltage detection circuit 30 is connected to the balancing control loop 10. The control module 40 is connected to the balancing control loop 10, the DC-DC conversion module 20, and the battery voltage detection circuit 30. The control module 40 is configured to acquire the maximum voltage signal and the minimum voltage signal of each individual cell 810. When the maximum voltage signal and the minimum voltage signal meet a preset voltage condition, the control module 40 controls the balancing control loop 10 to connect the individual cell 810 with the maximum voltage signal and the individual cell 810 with the minimum voltage signal, and controls the DC-DC conversion module 20 to replenish power from the individual cell 810 with the maximum voltage to the individual cell 810 with the minimum voltage.

[0059] The battery pack 80 under test may include multiple individual cells 810 connected in series. Each individual cell 810 is a rechargeable battery, and may be, but is not limited to, a lithium-ion battery. An equalization control loop 10 is used to connect the individual cell 810 with the highest voltage signal and the individual cell 810 with the lowest voltage signal in the battery pack 80 under test. The equalization control loop 10 is connected to a DC-DC converter module 20, which controls the individual cell 810 with the highest voltage signal to charge the individual cell 810 with the lowest voltage signal, thereby achieving equalization control of the corresponding individual cells 810.

[0060] Based on the connection of the battery voltage detection circuit 30 to the equalization control loop 10, when the equalization control loop 10 turns on the corresponding single cell 810, the battery voltage detection circuit 30 can detect the voltage signal of the corresponding single cell 810. When the equalization control loop 10 sequentially turns on each single cell 810, the battery voltage detection circuit 30 can detect the voltage signal of each single cell 810 and transmit each voltage signal to the control module 40.

[0061] The control module 40 is connected to the equalization control loop 10, the DC-DC conversion module 20, and the battery voltage detection circuit 30. The control module 40 can acquire the voltage signal of each individual battery cell 810, compare and process the voltage signals to obtain the corresponding maximum and minimum voltage signals. The control module 40 can perform difference processing on the amplitude of the maximum and minimum voltage signals to obtain the maximum difference. When the maximum difference is greater than the preset voltage threshold, the equalization control loop 10 is controlled to work. The equalization control loop 10 then connects the individual battery cell 810 with the maximum voltage signal and the individual battery cell 810 with the minimum voltage signal, and controls the DC-DC conversion module 20 to work, so that the individual battery cell 810 with the maximum voltage provides power to the individual battery cell 810 with the minimum voltage. The two individual batteries 810 are pulled up to compensate for the low voltage, so as to complete the active equalization process of the corresponding individual battery cell 810.

[0062] In the above embodiments, the equalization control loop 10 is connected to the battery pack 80 under test; the DC-DC conversion module 20 is connected to the equalization control loop 10; the battery voltage detection circuit 30 is connected to the equalization control loop 10; the control module 40 is connected to the equalization control loop 10, the DC-DC conversion module 20 and the battery voltage detection circuit 30 respectively; the control module 40 acquires the maximum voltage signal and the minimum voltage signal in each individual battery 810, and when the maximum voltage signal and the minimum voltage signal meet the preset voltage conditions, it controls the equalization control loop 10 to connect the individual battery 810 with the corresponding maximum voltage signal and the individual battery 810 with the corresponding minimum voltage signal, and controls the DC-DC conversion module 20 to replenish power from the individual battery 810 with the corresponding maximum voltage to the individual battery 810 with the corresponding minimum voltage, thereby achieving efficient and fast active equalization adjustment of the battery pack 80 under test. This application uses a battery voltage detection circuit 30 to detect the voltage of each individual battery cell 810. The control module 40 then controls the equalization control circuit 10 to operate based on the maximum and minimum voltage signals of each individual battery cell 810. This allows the equalization control circuit 10 to connect the individual battery cell 810 corresponding to the maximum voltage signal and the individual battery cell 810 corresponding to the minimum voltage signal, and also controls the DC-DC conversion module 20 to operate. This enables charging from the individual battery cell 810 with the maximum voltage to the individual battery cell 810 with the minimum voltage, resulting in only one power conversion efficiency loss and avoiding time interval losses. This improves the efficiency and speed of active battery equalization.

[0063] In one embodiment, such as Figure 2 and Figure 3As shown, the equalization control circuit 10 includes a discharge circuit 110 and a charging circuit 120. The discharge circuit 110 is connected to the DC-DC conversion module 20, the control module 40, and each individual battery cell 810. The charging circuit 120 is connected to the DC-DC conversion module 20, the control module 40, and each individual battery cell 810. The control module 40 is also configured to control the discharge circuit 110 to connect the individual battery cell 810 corresponding to the maximum voltage signal and the charging circuit 120 to connect the individual battery cell 810 corresponding to the minimum voltage signal when the maximum voltage signal and the minimum voltage signal meet preset voltage conditions.

[0064] The discharge circuit 110 is used to connect the individual battery 810 corresponding to the maximum voltage signal; the charging circuit 120 is used to connect the individual battery 810 corresponding to the minimum voltage signal. It should be noted that at any given time, the discharge circuit 110 can only connect one individual battery 810 corresponding to the maximum voltage signal; similarly, at any given time, the charging circuit 120 can only connect one individual battery 810 corresponding to the minimum voltage signal, in order to avoid short circuits in the battery pack 80 under test.

[0065] For example, the discharge circuit 110 is connected to the DC-DC conversion module 20, the control module 40, and each individual battery cell 810; the charging circuit 120 is connected to the DC-DC conversion module 20, the control module 40, and each individual battery cell 810. When the difference between the maximum voltage signal and the minimum voltage signal is greater than a preset voltage threshold, the control module 40 controls the discharge circuit 110 to work, so that the discharge circuit 110 connects to the individual battery cell 810 corresponding to the maximum voltage signal, and controls the charging circuit 120 to work, so that the charging circuit 120 connects to the individual battery cell 810 corresponding to the minimum voltage signal, and controls the DC-DC conversion module 20 to work, so that the individual battery cell 810 corresponding to the maximum voltage replenishes the individual battery cell 810 corresponding to the minimum voltage, thereby achieving efficient and rapid active balancing adjustment of the battery pack 80 under test.

[0066] In one embodiment, such as Figure 2 and Figure 3 As shown, the discharge circuit 110 includes a first battery selection module 112 and a first rectifier bridge commutation module 116; the charging circuit 120 includes a second battery selection module 122 and a second rectifier bridge commutation module 126; the first battery selection module 112 is connected to the control module 40 and each individual battery 810 respectively; the first rectifier bridge commutation module 116 is connected to the DC-DC converter module 20 and each individual battery 810 respectively; the second battery selection module 122 is connected to the control module 40 and each individual battery 810 respectively; the second rectifier bridge commutation module 126 is connected to the DC-DC converter module 20 and each individual battery 810 respectively.

[0067] The first battery selection module 112 is used to select the corresponding individual battery cell 810 to be connected, and the second battery selection module 122 is used to select the corresponding individual battery cell 810 to be connected. The first rectifier bridge commutation module 116 is used to control the discharge electrode DISCHARGE+ to be positive and DISCHARGE- to be negative, so as to connect the DC-DC conversion module 20; the second rectifier bridge commutation module 126 is used to control the charging electrode CHARGE+ to be positive and CHARGE- to be negative, so as to connect the DC-DC conversion module 20.

[0068] For example, when the difference between the maximum voltage signal and the minimum voltage signal is greater than a preset voltage threshold, the control module 40 controls the first battery selection module 112 to select and connect the single battery 810 corresponding to the maximum voltage signal, that is, to connect the single battery 810 corresponding to the maximum voltage signal to the first rectifier bridge commutation module 116. The first rectifier bridge commutation module 116 controls the discharge electrode DISCHARGE+ to be positive and DISCHARGE- to be negative; and controls the second battery selection module 122 to select and connect the single battery 810 corresponding to the minimum voltage signal, that is, to connect... The single cell 810 corresponding to the minimum voltage signal is connected to the second rectifier bridge commutation module 126. The second rectifier bridge commutation module 126 controls the charging electrode CHARGE+ to be positive and CHARGE- to be negative, and controls the DC-DC conversion module 20 to work. This allows the electrical signal of the single cell 810 corresponding to the maximum voltage to be charged by the first rectifier bridge commutation module 116, the DC-DC conversion module 20 and the second rectifier bridge commutation module 126, thereby achieving efficient and rapid active balancing adjustment of the battery pack 80 under test.

[0069] In one embodiment, such as Figure 2 and Figure 3As shown, the discharge circuit 110 further includes multiple first bidirectional switching transistor modules 118; the first battery selection module 112 includes multiple first battery selection modules 114; the charging circuit 120 further includes multiple second bidirectional switching transistor modules 128; the second battery selection module 122 includes multiple second battery selection modules 124; the negative terminal of a single battery 810 is connected to the first terminal of a corresponding first bidirectional switching transistor module 118, and the positive terminal of a single battery 810 is connected to the first terminal of another corresponding first bidirectional switching transistor module 118; the second terminal of each first bidirectional switching transistor module 118 is respectively connected to a first rectifier bridge commutation module 116. The control terminal of the bidirectional switching module 118 is connected to the corresponding first battery selection module 114, and each first battery selection module 114 is connected to the control module 40. The negative terminal of the single cell 810 is connected to the first terminal of the corresponding second bidirectional switching module 128, and the positive terminal of the single cell 810 is connected to the first terminal of another corresponding second bidirectional switching module 128. The second terminal of each second bidirectional switching module 128 is connected to the second rectifier bridge commutation module 126, and the control terminal of the second bidirectional switching module 128 is connected to the corresponding second battery selection module 124, and each second battery selection module 124 is connected to the control module 40.

[0070] The first bidirectional switching module 118 can be composed of one corresponding resistor and two N-type MOSFETs connected together. The two N-type MOSFETs are connected back-to-back through their sources. One N-type MOSFET is connected to the electrode of the corresponding single cell 810 through its drain, and the other N-type MOSFET is connected to the corresponding first battery selection module 114 through its drain. Similarly, the second bidirectional switching module 128 can be composed of one corresponding resistor and two corresponding N-type MOSFETs connected together. The two N-type MOSFETs are connected back-to-back through their sources. One N-type MOSFET is connected to the electrode of the corresponding single cell 810 through its drain, and the other N-type MOSFET is connected to the corresponding second battery selection module 124 through its drain.

[0071] For example, the battery pack 80 under test includes 10 individual cells 810 connected in series (such as individual cells CELL_H1 to CELL_H10). The first battery selection module 112 includes 11 first battery selection modules 114. The negative terminal of individual cell CELL_H1 is connected to the corresponding first battery selection module 114. The positive terminal of individual cell CELL_H1 and the negative terminal of CELL_H2 are connected to another corresponding first battery selection module 114, and so on. The second battery selection module 122 includes 11 second battery selection modules 124. The negative terminal of individual cell CELL_H1 is connected to the corresponding second battery selection module 124. The positive terminal of individual cell CELL_H1 and the negative terminal of CELL_H2 are connected to another corresponding second battery selection module 124, and so on. When the difference between the maximum voltage signal and the minimum voltage signal exceeds a preset voltage threshold, the control module 40 controls the corresponding first battery selection module 114 to turn on the corresponding first bidirectional switch module 118, thereby connecting the single battery 810 corresponding to the maximum voltage signal, i.e., connecting the single battery 810 corresponding to the maximum voltage signal with the first rectifier bridge commutation module 116; and controls the corresponding second battery selection module 124 to turn on the corresponding second bidirectional switch module 128, thereby connecting the single battery 810 corresponding to the minimum voltage signal, i.e., connecting the single battery 810 corresponding to the minimum voltage signal with the second rectifier bridge commutation module 126, and controls the DC-DC conversion module 20 to work, so that the electrical signal of the single battery 810 corresponding to the maximum voltage is charged to the single battery 810 corresponding to the minimum voltage after passing through the first rectifier bridge commutation module 116, the DC-DC conversion module 20 and the second rectifier bridge commutation module 126, thereby achieving efficient and fast active balancing adjustment of the battery pack 80 under test.

[0072] In one example, such as Figure 2 and Figure 3As shown, the first battery selection module 114 includes a first coupling isolator OP1, a first resistor R1, and a first bidirectional diode D1; the second battery selection module 124 includes a second coupling isolator OP2, a second resistor R2, and a second bidirectional diode D2; the first terminal of the first coupling isolator OP1 is connected to a first power supply, the second terminal of the first coupling isolator OP1 is connected to the first terminal of the first resistor R1, the second terminal of the first resistor R1 is connected to the first terminal of the first bidirectional diode D1, and the second terminal of the first bidirectional diode D1 is connected to another first battery selection module 114 corresponding to the positive terminal of the same single cell; the third terminal of the first coupling isolator OP1 is connected to a second power supply, the first... The fourth terminal of the coupling isolator OP1 is connected to the control terminal of the first bidirectional switching module 118 corresponding to the negative terminal of the same single cell; the first terminal of the second coupling isolator OP2 is connected to the first power supply, the second terminal of the second coupling isolator OP2 is connected to the first terminal of the second resistor R2, the second terminal of the second resistor R2 is connected to the first terminal of the second bidirectional diode D2, and the second terminal of the second bidirectional diode D2 is connected to another second battery selection module 124 corresponding to the positive terminal of the same single cell; the third terminal of the second coupling isolator OP2 is connected to the fifth power supply, and the fourth terminal of the second coupling isolator OP2 is connected to the control terminal of the second bidirectional switching module 128 corresponding to the negative terminal of the same single cell.

[0073] The first coupling isolator OP1 and the second coupling isolator OP2 are optocouplers. The first bidirectional diode D1 consists of two corresponding diodes connected opposite each other through their cathodes, and the anode of the first bidirectional diode D1 is connected to the anode of the first bidirectional diode D1 in another first battery selection module 114. The second bidirectional diode D2 consists of two corresponding diodes connected opposite each other through their cathodes, and the anode of the second bidirectional diode D2 is connected to the anode of the second bidirectional diode D2 in another second battery selection module 124.

[0074] For example, such as Figure 2 and Figure 3 As shown, the first rectifier bridge commutation module 116 includes a first switch, a second switch, a third switch, a fourth switch, a third coupling isolator, a fourth coupling isolator, a fifth coupling isolator, a sixth coupling isolator, a third resistor, a fourth resistor, a fifth resistor, a sixth resistor, a seventh resistor, an eighth resistor, a ninth resistor, a tenth resistor, and an eleventh resistor; the second rectifier bridge commutation module 126 includes a fifth switch, a sixth switch, a seventh switch, an eighth switch, a seventh coupling isolator, an eighth coupling isolator, a ninth coupling isolator, a tenth coupling isolator, a twelfth resistor, a thirteenth resistor, a fourteenth resistor, a fifteenth resistor, a sixteenth resistor, a seventeenth resistor, an eighteenth resistor, a nineteenth resistor, and a twentieth resistor.

[0075] The drain of the first switching transistor is connected to the first positive terminal of the DC-DC converter module 20, the source of the first switching transistor is connected to the drain of the third switching transistor, and the gate of the first switching transistor is connected to the fourth terminal of the third coupling isolator; the drain of the second switching transistor is connected to the first positive terminal of the DC-DC converter module 20, the source of the second switching transistor is connected to the drain of the fourth switching transistor, and the gate of the second switching transistor is connected to the fourth terminal of the fourth coupling isolator; the source of the third switching transistor is connected to the first negative terminal of the DC-DC converter module 20, and the gate of the third switching transistor is connected to the fourth terminal of the fifth coupling isolator; the source of the fourth switching transistor is connected to the first negative terminal of the DC-DC converter module 20, and the gate of the fourth switching transistor is connected to the fourth terminal of the sixth coupling isolator; the first terminal of the third coupling isolator is connected to the corresponding first bidirectional switching transistor module 118, the second terminal of the third coupling isolator is connected to the first terminal of the third resistor, the second terminal of the third resistor is connected to the corresponding first bidirectional switching transistor module 118, and the third terminal of the third coupling isolator is connected to the third power supply.

[0076] The first terminal of the fourth coupling isolator is connected to the first terminal of the fifth coupling isolator and the source of the second switching transistor, respectively. The second terminal of the fourth coupling isolator is connected to the first terminal of the fourth resistor. The second terminal of the fourth resistor is connected to the first terminal of the fifth resistor and the drain of the third switching transistor, respectively. The third terminal of the fourth coupling isolator is connected to the second power supply. The second terminal of the fifth coupling isolator is connected to the second terminal of the fifth resistor. The third terminal of the fifth coupling isolator is connected to the third terminal of the sixth coupling isolator. The first terminal of the sixth coupling isolator is connected to the corresponding first bidirectional switching transistor module 118. The second terminal of the sixth coupling isolator is connected to the first terminal of the sixth resistor. The second terminal of the sixth resistor is connected to the corresponding first bidirectional switching transistor module 118. The third terminal of the sixth coupling isolator is connected to the first terminal of the seventh resistor, and the second terminal of the seventh resistor is connected to the fourth power supply; the first terminal of the eighth resistor is connected to the fourth terminal of the third coupling isolator, and the second terminal of the eighth resistor is connected to the source of the first switching transistor and the corresponding first bidirectional switching transistor module 118; the first terminal of the ninth resistor is connected to the fourth terminal of the fourth coupling isolator, and the second terminal of the ninth resistor is connected to the source of the second switching transistor; the first terminal of the tenth resistor is connected to the fourth terminal of the fifth coupling isolator, and the second terminal of the tenth resistor is connected to the first negative terminal of the DC-DC converter module 20; the first terminal of the eleventh resistor is connected to the fourth terminal of the sixth coupling isolator, and the second terminal of the eleventh resistor is connected to the first negative terminal of the DC-DC converter module 20.

[0077] The drain of the fifth switch is connected to the second positive terminal of the DC-DC converter module 20, the source of the fifth switch is connected to the drain of the seventh switch, and the gate of the fifth switch is connected to the fourth terminal of the seventh coupling isolator. The drain of the sixth switch is connected to the second positive terminal of the DC-DC converter module 20, the source of the sixth switch is connected to the drain of the eighth switch, and the gate of the sixth switch is connected to the fourth terminal of the eighth coupling isolator. The source of the seventh switch is connected to the second negative terminal of the DC-DC converter module 20, and the gate of the seventh switch is connected to the fourth terminal of the ninth coupling isolator. The source of the eighth switch is connected to the second negative terminal of the DC-DC converter module 20, and the gate of the eighth switch is connected to the fourth terminal of the tenth coupling isolator. The first terminal of the seventh coupling isolator is connected to the corresponding second bidirectional switch module 128, the second terminal of the seventh coupling isolator is connected to the first terminal of the twelfth resistor, the second terminal of the twelfth resistor is connected to the corresponding second bidirectional switch module 128, and the third terminal of the seventh coupling isolator is connected to the sixth power supply.

[0078] The first terminal of the eighth coupling isolator is connected to the first terminal of the ninth coupling isolator and the source of the sixth switch. The second terminal of the eighth coupling isolator is connected to the first terminal of the thirteenth resistor. The second terminal of the thirteenth resistor is connected to the first terminal of the fourteenth resistor and the drain of the seventh switch. The third terminal of the eighth coupling isolator is connected to the fifth power supply. The second terminal of the ninth coupling isolator is connected to the second terminal of the fourteenth resistor. The third terminal of the ninth coupling isolator is connected to the third terminal of the tenth coupling isolator. The first terminal of the tenth coupling isolator is connected to the corresponding second bidirectional switch module 128. The second terminal of the tenth coupling isolator is connected to the first terminal of the fifteenth resistor. The second terminal of the fifteenth resistor is connected to the corresponding second bidirectional switch module 128. The third terminal of the coupling isolator is connected to the first terminal of the sixteenth resistor, and the second terminal of the sixteenth resistor is connected to the fourth power supply; the first terminal of the seventeenth resistor is connected to the fourth terminal of the seventh coupling isolator, and the second terminal of the seventeenth resistor is connected to the source of the sixth switch and the corresponding second bidirectional switch module 128; the first terminal of the eighteenth resistor is connected to the fourth terminal of the eighth coupling isolator, and the second terminal of the eighteenth resistor is connected to the source of the sixth switch; the first terminal of the nineteenth resistor is connected to the fourth terminal of the ninth coupling isolator, and the second terminal of the nineteenth resistor is connected to the second negative terminal of the DC-DC converter module 20; the first terminal of the twentieth resistor is connected to the fourth terminal of the tenth coupling isolator, and the second terminal of the twentieth resistor is connected to the second negative terminal of the DC-DC converter module 20.

[0079] In one embodiment, such as Figure 6 As shown, the battery active balancing circuit also includes a discharge auxiliary isolation power supply 510 and a charging auxiliary isolation power supply 520; the discharge auxiliary isolation power supply 510 is connected to the discharge circuit 110; and the charging auxiliary isolation power supply 520 is connected to the charging circuit 120.

[0080] The discharge auxiliary isolation power supply 510 uses a push-pull chip to drive the transformer, outputting two mutually isolated auxiliary power supplies, Vax1 and Vax2. The charging auxiliary isolation power supply 520 uses a push-pull chip to drive the corresponding transformer, outputting two mutually isolated auxiliary power supplies, Vax3 and Vax4. The negative terminal of auxiliary power supply Vax1 of the discharge auxiliary isolation power supply 510 is connected to DISCHR_A of the discharge circuit 110, and the negative terminal of auxiliary power supply Vax2 is connected to DISCHR_B of the discharge circuit 110; the negative terminal of auxiliary power supply Vax3 of the discharge auxiliary isolation power supply 510 is connected to CHRG_A of the charging circuit 120, and the negative terminal of auxiliary power supply Vax4 is connected to CHRG_B of the charging circuit 120.

[0081] For example, for discharge circuit 110, if CELL_H1 is selected to be activated, then individual battery 810 is connected to DISCHR_A and DISCHR_B, with the voltage of DISCHR_B being higher than that of DISCHR_A. If individual battery CELL_H2 is selected to be activated, then individual battery 810 is connected to DISCHR_A and DISCHR_B, with the voltage of DISCHR_A being higher than that of DISCHR_B. For charging circuit 120, if CELL_L1 is selected to be activated, then individual battery 810 is connected to CHR_A and CHR_B, with the voltage of CHR_B being higher than that of CHR_A. If CELL_L2 is selected to be activated, then individual battery 810 is connected to CHR_A and CHR_B, with the voltage of CHR_A being higher than that of CHR_B.

[0082] The condition for the N-type MOSFET in the first rectifier bridge commutation module 116 to conduct is that the voltage applied to the gate of the N-type MOSFET is higher than that at the source. Based on the discharge auxiliary isolation power supply 510 connected to the first rectifier bridge commutation module 116, when the corresponding coupling isolator in the first rectifier bridge commutation module 116 is turned on, the voltage supplied to the gate of the N-type MOSFET by the corresponding auxiliary power supply is higher than the voltage of the corresponding first bidirectional switching module 118, thus enabling the N-type MOSFET to turn on, achieving high-side conduction of the N-type MOSFET in the first rectifier bridge commutation module 116. Similarly, the condition for the N-type MOSFET in the second rectifier bridge commutation module 126 to conduct is that the voltage applied to the gate of the N-type MOSFET is higher than that at the source. Based on the charging auxiliary isolation power supply 520 connected to the second rectifier bridge commutation module 126, when the corresponding coupling isolator in the second rectifier bridge commutation module 126 is turned on, the voltage of the corresponding auxiliary power supply provided to the gate of the N-type MOS transistor is higher than the voltage of the corresponding second bidirectional switching transistor module 128, so the N-type MOS transistor can be turned on, realizing the high-side conduction of the N-type MOS transistor in the second rectifier bridge commutation module 126.

[0083] In one embodiment, such as Figure 4 , Figure 5 and Figure 11As shown, the first battery selection module 112 includes multiple first electronic switches S1 and a third bidirectional diode D3; the second battery selection module 122 includes multiple second electronic switches S2 and a fourth bidirectional diode D4; the negative terminal of a single cell 810 is connected to the first terminal of a corresponding first electronic switch S1, and the positive terminal of a single cell 810 is connected to the first terminal of another corresponding first electronic switch S1; the second terminal of each first electronic switch S1 is connected to the first rectifier bridge commutation module 116, the control terminal of the first electronic switch S1 is connected to the first terminal of a corresponding third bidirectional diode D3, and the second terminal of the third bidirectional diode D3 is connected to another first battery selection module 114 corresponding to the positive terminal of the same single cell; the third bidirectional diode D3... The control terminal of the second end is connected to the control module 40, and the power supply terminal of the first electronic switch S1 is connected to the seventh power supply; the negative terminal of the single cell 810 is connected to the first terminal of the corresponding second electronic switch S2, and the positive terminal of the single cell 810 is connected to the first terminal of another corresponding second electronic switch S2; the second terminal of each second electronic switch S2 is connected to the second rectifier bridge commutation module 126, the control terminal of the second electronic switch S2 is connected to the first terminal of the corresponding fourth bidirectional diode D4, and the second terminal of the fourth bidirectional diode D4 is connected to another second battery selection module 124 corresponding to the positive terminal of the same single cell; the control terminal of the second terminal of the fourth bidirectional diode D4 is connected to the control module 40, and the power supply terminal of the second electronic switch S2 is connected to the seventh power supply.

[0084] The first electronic switch S1 and the second electronic switch S2 can be based on magnetic isolation or capacitive isolation driving, combined with NMOS transistor packages, which can achieve higher integration, reduce the size of the equalization circuit, and improve reliability. The first electronic switch S1 can be a magnetically isolated electronic switch or a capacitive isolation electronic switch; the second electronic switch S2 can be a magnetically isolated electronic switch or a capacitive isolation electronic switch.

[0085] For example, discharge circuit 110 has DISCHR_A and DISCHR_B connected to the power supply line. First electronic switches S1SD1 to SD11 connect the electrodes of each individual battery cell 810 to DISCHR_A and DISCHR_B of discharge circuit 110. First rectifier bridge commutation module 116 can be composed of electronic switches SR1 to SR4 to fix the discharge electrodes DISCHARGE+ of discharge circuit 110 as positive and DISCHARGE- as negative. Charging circuit 120 has CHR_A and CHR_B connected to the power supply line. Second electronic switches S2SC1 to SC11 connect the electrodes of each individual battery cell 810 to CHR_A and CHR_B of charging circuit 120. Second rectifier bridge commutation module 126 can be composed of electronic switches SR5 to SR8 to fix the charging electrodes CHARGE+ of discharge circuit 110 as positive and CHARGE- as negative. Because the electronic switch contains an isolated DC-DC driver, the electronic switch is turned on when the isolated power supply is working and turned off when the isolated power supply is not working. There is no need to set up an auxiliary isolated power supply, an isolated optocoupler for the discharge circuit 110 and the charging circuit 120. This greatly simplifies the circuit connecting the discharge circuit 110 and the charging circuit 120, reduces the number of components in the circuit, and further improves the reliability of the circuit.

[0086] In one embodiment, such as Figure 7 and Figure 8 As shown, the battery active balancing circuit also includes a discharge selection decoding circuit 610 and a charge selection decoding circuit 620; the discharge selection decoding circuit 610 is connected between the discharge circuit 110 and the control module 40; the charge selection decoding circuit 620 is connected between the charging circuit 120 and the control module 40.

[0087] The discharge selection decoding circuit 610 is used to ensure that the battery is not short-circuited during any preparation stage of the system during power-on and reset, and to ensure that no battery cell is connected to the discharge circuit 110. During the active balancing process, only one single battery cell 810 is connected to the discharge circuit 110 when the DC-DC conversion module 20 is turned on.

[0088] The charging selection decoding circuit 620 is used to ensure that the battery is not short-circuited during any preparation stage of the system during power-on and reset, and to ensure that no battery cell is connected to the charging circuit 120. During the active balancing process, only one single battery cell 810 is connected to the charging circuit 120 when the DC-DC conversion module 20 is turned on.

[0089] In one embodiment, such as Figure 9As shown, the DC-DC converter module 20 includes a DC-DC chip P1 and an eleventh coupling isolator OP11; the input terminal of the eleventh coupling isolator OP11 is connected to the control module 40, the output terminal of the eleventh coupling isolator OP11 is connected to the DC-DC chip P1, and the DC-DC chip P1 is connected to the equalization control loop 10.

[0090] Among them, the eleventh coupling isolator OP11 is an optocoupler isolator.

[0091] For example, such as Figure 2 , Figure 3 , Figure 11 and Figure 12 The battery voltage detection circuit 30 shown is connected to DISCHARGE+ and DISCHARGE- of the discharge circuit 110. When the DC-DC conversion module 20 is not working, only the battery detection resistors RS1 and RS2 are connected in series on the battery voltage detection circuit 30 to generate a weak current. The voltage of resistor RS2 on the circuit is proportional to the voltage of a single cell 810. When the discharge selection decoding circuit 610 is sequentially connected to each cell 810, the battery voltage detection circuit 30 measures the voltage of each cell 810. The control module 40 records the highest and lowest battery voltages and determines the voltage difference between them. If the voltage difference is greater than a preset threshold (e.g., set to 2mV), the cell 810 with the highest battery voltage is connected for discharge. Circuit 110 connects to charging circuit 120 for the cell 810 with the lowest battery voltage. Control module 40 transmits an enable signal to DC-DC chip P1 through eleventh coupling isolator OP11, causing DC-DC chip P1 to start working according to the enable signal. It directly replenishes the battery power from the cell 810 with the highest battery voltage to the cell 810 with the lowest battery voltage, so that the two cells 810 are balanced by the high voltage and the low voltage, thus achieving active battery balancing. During the battery charging stage, each cell 810 is fully charged as much as possible. During the battery discharging stage, each cell 810 is discharged as evenly and consistently as possible, effectively extending battery life, improving the efficiency of active battery balancing, and increasing the speed of active battery balancing.

[0092] In one embodiment, such as Figure 10 As shown, the battery active balancing circuit also includes a communication interface circuit 70; the communication interface circuit 70 is connected to the control module 40 and is used to connect to the battery management system.

[0093] The communication interface circuit 70 may be, but is not limited to, a CAN communication interface circuit 70.

[0094] During the operation of the DC-DC converter module 20, both the charging circuit 120 and the discharging circuit 110 carry current (typically 1A to 2A). The turn-on resistance of the N-type MOSFET in the circuit is approximately 10 to 30 milliohms. The current flow generates a voltage difference of tens of mV, resulting in an error between the measured voltage value and the actual value. The battery management system (BMS) monitors the battery voltage in real time, typically with a check cycle of no more than 10 milliseconds. If the BMS communicates with the battery active balancing circuit, the DC-DC converter module 20 is activated when a voltage difference exists between any two individual cells 810, and deactivated when the voltage difference between the two cells decreases to a predetermined value, thereby further improving balancing efficiency.

[0095] In one embodiment, a battery system is also provided, including a battery pack under test, a battery management system, and a battery active balancing circuit as described above; the battery management system is connected to the battery pack under test, and the battery active balancing circuit is connected to both the battery pack under test and the battery management system.

[0096] The specific descriptions of the battery pack under test, the battery management system, and the active battery balancing circuit are as described in the above embodiments and will not be repeated here.

[0097] The battery management system connects to the battery pack under test (TBD). An active battery balancing circuit connects the TBD and the battery management system. The active battery balancing circuit includes a balancing control loop, a DC-DC converter module, a battery voltage detection circuit, and a control module. The balancing control loop connects to the TBD. The TBD includes multiple individual cells connected in series. The DC-DC converter module connects to the balancing control loop. The battery voltage detection circuit connects to the balancing control loop. The control module connects to the balancing control loop, the DC-DC converter module, and the battery voltage detection circuit. The control module is configured to acquire the maximum and minimum voltage signals of each individual cell. When the maximum and minimum voltage signals meet preset voltage conditions, the control loop connects the individual cell corresponding to the maximum voltage signal and the individual cell corresponding to the minimum voltage signal. The control module also connects the DC-DC converter module to charge the individual cell from the cell with the maximum voltage to the cell with the minimum voltage, achieving efficient and rapid active balancing of the TBD.

[0098] In the above embodiments, the voltage of each individual battery cell is detected by the battery voltage detection circuit. The control module then controls the equalization control loop to operate based on the maximum and minimum voltage signals of each individual battery cell. This allows the equalization control loop to connect the individual battery cell corresponding to the maximum voltage signal and the individual battery cell corresponding to the minimum voltage signal, and controls the DC-DC conversion module to operate. This enables charging from the individual battery cell corresponding to the maximum voltage to the individual battery cell corresponding to the minimum voltage, resulting in only one power conversion efficiency loss and avoiding time interval losses. This improves the efficiency of active battery equalization, increases the speed of active battery equalization, and extends the lifespan of the battery system.

[0099] The technical features of the above embodiments can be combined in any way. For the sake of brevity, 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.

[0100] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the utility model patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

Claims

1. A battery active balancing circuit, characterized in that, include: A balancing control loop is connected to the battery pack under test; the battery pack under test includes multiple individual cells, and each individual cell is connected in series. A DC-DC conversion module, wherein the DC-DC conversion module is connected to the equalization control loop; A battery voltage detection circuit, which is connected to the equalization control loop; A control module is provided; the control module is connected to the equalization control loop, the DC-DC conversion module, and the battery voltage detection circuit; the control module is configured to acquire the maximum voltage signal and the minimum voltage signal of each individual battery cell, and when the maximum voltage signal and the minimum voltage signal meet a preset voltage condition, control the equalization control loop to connect the individual battery cell corresponding to the maximum voltage signal and the individual battery cell corresponding to the minimum voltage signal, and control the DC-DC conversion module to replenish power from the individual battery cell corresponding to the maximum voltage to the individual battery cell corresponding to the minimum voltage.

2. The battery active balancing circuit according to claim 1, characterized in that, The equalization control circuit includes a discharge circuit and a charging circuit; The discharge circuit is connected to the DC-DC conversion module, the control module, and each of the individual battery cells; the charging circuit is connected to the DC-DC conversion module, the control module, and each of the individual battery cells. The control module is further configured to control the discharge circuit to connect to the single cell corresponding to the maximum voltage signal and the charging circuit to connect to the single cell corresponding to the minimum voltage signal when the maximum voltage signal and the minimum voltage signal meet preset voltage conditions.

3. The battery active balancing circuit according to claim 2, characterized in that, The discharge circuit includes a first battery selection module and a first rectifier bridge commutation module; the charging circuit includes a second battery selection module and a second rectifier bridge commutation module. The first battery selection module is connected to the control module and each of the individual batteries; the first rectifier bridge commutation module is connected to the DC-DC conversion module and each of the individual batteries. The second battery selection module is connected to the control module and each of the individual batteries respectively; the second rectifier bridge commutation module is connected to the DC-DC conversion module and each of the individual batteries respectively.

4. The battery active balancing circuit according to claim 3, characterized in that, The discharge circuit further includes multiple first bidirectional switching transistor modules; the first battery selection module includes multiple first battery selection modules; the charging circuit further includes multiple second bidirectional switching transistor modules; the second battery selection module includes multiple second battery selection modules. The negative terminal of each individual battery is connected to the first terminal of the corresponding first bidirectional switching transistor module, and the positive terminal of each individual battery is connected to the first terminal of another corresponding first bidirectional switching transistor module; the second terminal of each first bidirectional switching transistor module is connected to the first rectifier bridge commutation module, the control terminal of the first bidirectional switching transistor module is connected to the corresponding first battery selection module, and each first battery selection module is connected to the control module. The negative terminal of each individual battery is connected to the first terminal of the corresponding second bidirectional switching module, and the positive terminal of each individual battery is connected to the first terminal of another corresponding second bidirectional switching module; the second terminal of each second bidirectional switching module is connected to the second rectifier bridge commutation module, the control terminal of the second bidirectional switching module is connected to the corresponding second battery selection module, and each second battery selection module is connected to the control module.

5. The battery active balancing circuit according to claim 4, characterized in that, The first battery selection module includes a first coupling isolator, a first resistor, and a first bidirectional diode; the second battery selection module includes a second coupling isolator, a second resistor, and a second bidirectional diode. The first end of the first coupling isolator is connected to the first power supply, the second end of the first coupling isolator is connected to the first end of the first resistor, the second end of the first resistor is connected to the first end of the first bidirectional diode, and the second end of the first bidirectional diode is connected to another first battery selection module corresponding to the positive terminal of the same single cell; the third end of the first coupling isolator is connected to the second power supply, and the fourth end of the first coupling isolator is connected to the control terminal of the first bidirectional switching module corresponding to the negative terminal of the same single cell. The first end of the second coupling isolator is connected to the first power supply, the second end of the second coupling isolator is connected to the first end of the second resistor, the second end of the second resistor is connected to the first end of the second bidirectional diode, and the second end of the second bidirectional diode is connected to another second battery selection module corresponding to the positive terminal of the same single cell; the third end of the second coupling isolator is connected to the fifth power supply, and the fourth end of the second coupling isolator is connected to the control terminal of the second bidirectional switching module corresponding to the negative terminal of the same single cell.

6. The battery active balancing circuit according to claim 3, characterized in that, The first battery selection module includes multiple first electronic switches and a third bidirectional diode; the second battery selection module includes multiple second electronic switches and a fourth bidirectional diode. The negative terminal of each individual battery is connected to the first terminal of the corresponding first electronic switch, and the positive terminal of each individual battery is connected to the first terminal of another corresponding first electronic switch; the second terminal of each first electronic switch is connected to the first rectifier bridge commutation module, the control terminal of the first electronic switch is connected to the first terminal of the corresponding third bidirectional diode, the second terminal of the third bidirectional diode is connected to another first battery selection module corresponding to the positive terminal of the same individual battery cell; the control terminal of the second terminal of the third bidirectional diode is connected to the control module, and the power supply terminal of the first electronic switch is connected to the seventh power supply. The negative terminal of each individual battery is connected to the first terminal of the corresponding second electronic switch, and the positive terminal of each individual battery is connected to the first terminal of another corresponding second electronic switch; the second terminal of each second electronic switch is connected to the second rectifier bridge commutation module, the control terminal of the second electronic switch is connected to the first terminal of the corresponding fourth bidirectional diode, and the second terminal of the fourth bidirectional diode is connected to another second battery selection module corresponding to the positive terminal of the same individual battery cell; the control terminal of the second terminal of the fourth bidirectional diode is connected to the control module, and the power supply terminal of the second electronic switch is connected to the seventh power supply.

7. The battery active balancing circuit according to claim 2, characterized in that, It also includes discharge-assisted isolation power supplies and charging-assisted isolation power supplies; The discharge-assisted isolation power supply is connected to the discharge circuit; the charging-assisted isolation power supply is connected to the charging circuit.

8. The battery active balancing circuit according to claim 2, characterized in that, It also includes a discharge selection decoding circuit and a charge selection decoding circuit; The discharge selection decoding circuit is connected between the discharge circuit and the control module; the charge selection decoding circuit is connected between the charging circuit and the control module.

9. The battery active balancing circuit according to any one of claims 1 to 8, characterized in that, The DC-DC conversion module includes a DC-DC chip and an eleventh coupling isolator; The input terminal of the eleventh coupling isolator is connected to the control module, the output terminal of the eleventh coupling isolator is connected to the DC-DC chip, and the DC-DC chip is connected to the equalization control loop.

10. A battery system, characterized in that, Includes the battery pack under test, the battery management system, and the active battery balancing circuit as described in any one of claims 1 to 8; The battery management system is connected to the battery pack under test, and the active battery balancing circuit is connected to both the battery pack under test and the battery management system.

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