Equalization circuit and energy storage device

Abstract

The invention relates to an equalization circuit and energy storage equipment, and the circuit comprises a control module which is used for controlling a secondary winding in a flyback circuit to be in a cut-off state when a drive control signal is at a first level, and controlling the secondary winding in the flyback circuit to be in a conduction state when the drive control signal is at a second level; the channel selection module corresponding to the target synchronous rectification module is used for responding to the enable signal of the target cell and conducting a power supply path between the power supply module and the target synchronous rectification module so as to control the target synchronous rectification module to be in a working state; and the target synchronous rectification module is used for conducting a charging path between the target battery cell and the secondary winding corresponding to the target battery cell when the target synchronous rectification module is in a working state and the secondary winding in the flyback circuit is in a conducting state, so that the secondary winding corresponding to the target battery cell charges the target battery cell through the charging path. By adopting the circuit, battery cell equalization can be flexibly realized.

Description

Technical Field

[0001] The present application relates to the field of new energy technology, and in particular to a balancing circuit and an energy storage device. Background Art

[0002] With the development of new energy sources, energy storage systems typically utilize multiple battery cells connected in series. However, due to manufacturing variations, the capacity of each cell generally varies slightly. During use, the lower-capacity cells in the battery pack age faster than the others. Furthermore, the capacity differences accumulate over time, leading to some cells eventually failing due to cycle life, causing energy storage system failure. Therefore, balancing multiple cells is essential.

[0003] However, the current balancing approach is less flexible. Summary of the Invention

[0004] Based on this, it is necessary to provide a flexible balancing circuit and energy storage device to address the above technical problems.

[0005] In a first aspect, the present application provides a balancing circuit, including a control module, a power supply module, at least one synchronous rectifier module, and a channel selection module corresponding to each synchronous rectifier module, each synchronous rectifier module is respectively connected to a corresponding battery cell and a corresponding secondary winding in a flyback circuit, and the channel selection module is also connected to the power supply module and the corresponding synchronous rectifier module;

[0006] a control module, configured to output a drive control signal to control the secondary winding in the flyback circuit to be in an off state when the drive control signal is at a first level, and to control the secondary winding in the flyback circuit to be in an on state when the drive control signal is at a second level;

[0007] The channel selection module corresponding to the target synchronous rectification module is used to respond to the enable signal of the target battery cell, conduct the power supply path between the power supply module and the target synchronous rectification module, so that the power supply module supplies power to the target synchronous rectification module through the power supply path, so as to control the target synchronous rectification module to be in a working state; the target battery cell includes at least one of each battery cell, and the target synchronous rectification module is the synchronous rectification module corresponding to the target battery cell;

[0008] The target synchronous rectification module is used to conduct the charging path between the target battery cell and the secondary winding corresponding to the target battery cell when it is in working state and the secondary winding in the flyback circuit is in the on state, so that the secondary winding corresponding to the target battery cell charges the target battery cell through the charging path.

[0009] In a second aspect, the present application further provides an energy storage device, which includes at least one battery cell and the above-mentioned balancing circuit.

[0010] The above balancing circuit and energy storage device include a control module, a power supply module, at least one synchronous rectification module, and a channel selection module corresponding to each synchronous rectification module. Each synchronous rectification module is connected to a corresponding battery cell and a corresponding secondary winding in the flyback circuit. The channel selection module is also connected to the power supply module and the corresponding synchronous rectification module. The control module can output a drive control signal to control the secondary winding in the flyback circuit to be in an off state when the drive control signal is at a first level, and to control the secondary winding in the flyback circuit to be in an on state when the drive control signal is at a second level. Since the target battery cell includes at least one of the battery cells, the target synchronous rectification module is the synchronous rectification module corresponding to the target battery cell, and the channel selection module corresponding to the target synchronous rectification module is used to respond to the enable signal of the target battery cell to turn on the power supply path between the power supply module and the target synchronous rectification module, so that the power supply module supplies power to the target synchronous rectification module through the power supply path to control the target synchronous rectification module to be in a working state. In addition, the target synchronous rectification module is used to turn on the charging path between the target battery cell and the corresponding secondary winding in the flyback circuit when it is in the working state and the secondary winding in the flyback circuit is in the on state, so that the corresponding secondary winding of the target battery cell charges the target battery cell through the charging path. Therefore, the target battery cell to be balanced can be selected autonomously by the enable signal, and the target battery cell is balanced by the secondary winding in the flyback circuit, which has good flexibility. BRIEF DESCRIPTION OF DRAWINGS

[0011] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the related art, the drawings needed to be used in the description of the embodiments of the present application or the related art will be briefly introduced. Obviously, the drawings in the following description are only some embodiments of the present application, and other related drawings can be obtained by those skilled in the art without creative labor.

[0012] Figure 1 It is a schematic diagram of a balancer in the related art;

[0013] Figure 2 It is a schematic diagram of another balancer in the related art;

[0014] Figure 3 It is a schematic diagram of another balancer in the related art;

[0015] Figure 4 It is a schematic diagram of a balancing circuit in an embodiment;

[0016] Figure 5 It is a schematic diagram of a flyback circuit in an embodiment;

[0017] Figure 6is a schematic diagram of a synchronous rectification module in one embodiment;

[0018] Figure 7 is a schematic diagram of yet another synchronous rectification module according to an embodiment;

[0019] Figure 8 is a schematic diagram of yet another synchronous rectification module according to an embodiment;

[0020] Figure 9 is a schematic diagram of a constant current module in one embodiment;

[0021] Figure 10 is a schematic diagram of yet another constant current module in one embodiment;

[0022] Figure 11 is a schematic diagram of a channel selection module in one embodiment;

[0023] Figure 12 is a schematic diagram of yet another channel selection module in one embodiment;

[0024] Figure 13 is a schematic diagram of a power supply module in one embodiment;

[0025] Figure 14 is a schematic diagram of yet another power supply module in an embodiment;

[0026] Figure 15 is a schematic diagram of yet another equalization circuit in one embodiment;

[0027] Figure 16 is a schematic diagram of yet another startup module in one embodiment;

[0028] Figure 17 is a schematic structural diagram of an equalization circuit in one embodiment;

[0029] Figure 18 Schematic diagram of an energy storage device in one embodiment. DETAILED DESCRIPTION

[0030] In order to make the purpose, technical solutions and advantages of this application more clear, the following further describes this application in detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain this application and are not intended to limit this application.

[0031] Figure 1 is a schematic diagram of an equalizer in the related art, Figure 1 An isolated power supply active equalizer is shown. Figure 1As shown, the equalizer includes an input power supply 101, an isolation power supply 102, a transistor array 103, a processor 104, and a plurality of battery cells 105. The equalization current of this equalization mode is precisely controllable, but a large number of transistors are needed to form the transistor array for positive and negative switching and battery cell selection. If the number of battery cells is low, the cost of the processor is high. In addition, the processor is generally needed to switch the transistor array, which is inconvenient to use. Moreover, only a single battery cell can be equalized at the same time, which is low in efficiency.

[0032] Figure 2 FIG. 4 is a schematic diagram of another equalizer in the related art, Figure 2 FIG. 5 shows a push-pull transformer type active equalizer, Figure 2 As shown, the equalizer includes a push-pull transformer 201, a plurality of push-pull transistors 202, and a battery cell 203 corresponding to each push-pull transistor 202. This mode has a low cost, but the equalization current is completely uncontrollable, and the current size depends only on the voltage difference between the battery cells. When the voltage difference between the battery cells is small (for example, in the application scenario of lithium iron phosphate batteries), the equalization ability is weak, and it is usually only suitable for application scenarios of ternary lithium and lithium cobalt oxide batteries. In addition, this mode can only equalize all battery cells at the same time and cannot select part of the battery cells for equalization.

[0033] Figure 3 FIG. 6 is a schematic diagram of another equalizer in the related art, Figure 3 FIG. 7 shows a kickback type active equalizer, Figure 3 As shown, the equalizer includes an input power supply 301, a flyback converter 302, and a plurality of battery cells 303. This mode also has a low cost, but the disadvantages are similar to those of the push-pull transformer type active equalizer. Figure 2 In addition, this equalization mode usually uses a diode for fine rectification at the output. The voltage drop of the diode is different under different current conditions, and the equalization efficiency is extremely low.

[0034] Therefore, it is necessary to provide a more flexible equalization circuit, which will be described below.

[0035] Figure 4 FIG. 8 is a schematic diagram of an equalization circuit in an embodiment, Figure 4 As shown, in an embodiment, the equalization circuit 400 includes a control module 401, a power supply module 402, at least one synchronous rectification module 403, and a channel selection module 404 corresponding to each synchronous rectification module 403. Each synchronous rectification module 403 is connected to a corresponding battery cell 405 and a corresponding secondary winding 407 in the flyback circuit 406, and the channel selection module 404 is further connected to the power supply module 402 and the corresponding synchronous rectification module 403.

[0036] Optionally, the number of cells 405 is the same as the number of secondary windings 407, and each synchronous rectifier module 403 corresponds to a cell 405 and a secondary winding 407, and each synchronous rectifier module 403 corresponds to a channel selection module 404. Figure 4 Three battery cells 405 are used as an example. This embodiment does not limit the number of battery cells 405 as long as the number of battery cells 405 is greater than one.

[0037] The control module 401 is configured to output a drive control signal, denoted as TFDRV. The drive control signal is used to control the state of the secondary winding 407 in the flyback circuit 406 and includes, but is not limited to, a pulse width modulation (PWM) signal. The drive control signal includes a first level or a second level. The first level and the second level are two different logic states or voltage states. For example, the first level may be a high level, and the second level may be a low level.

[0038] Furthermore, when the driving control signal is at the first level, the control module 401 controls the secondary winding 407 in the flyback circuit 406 to be in the off state. When the driving control signal is at the second level, the control module 401 controls the secondary winding 407 in the flyback circuit 406 to be in the on state.

[0039] Figure 5 FIG. 1 is a schematic diagram of a flyback circuit in one embodiment, Figure 5 As shown, the flyback circuit 406 includes a power supply 501, a capacitor 502, a resistor 503, a capacitor 504, a diode 505, a transformer 506, a power supply 507, a capacitor 508, and a diode 509. The four sets of secondary windings 407 are respectively connected to the corresponding battery cells 405 through the corresponding synchronous rectification modules 403. It should be noted that, Figure 5 The embodiment shows a total of four secondary windings 407, but this embodiment is not limited thereto. S1+ represents the positive electrode of the first secondary winding 407, S1- represents the negative electrode of the first secondary winding 407, S2+ represents the positive electrode of the second secondary winding 407, and S2- represents the negative electrode of the second secondary winding 407. The same applies to other embodiments and are not further described here.

[0040] Optional, Figure 5 The secondary winding 407 may be formed by twisting four wires and then winding them together to keep the direct current resistance (DCR) and the single-channel inductance / leakage inductance as consistent as possible.

[0041] Please continue to refer to Figure 5Optionally, the control module 401 comprises a first control element (not shown in the figure) and a control transistor 4011. The first control element is configured to output a driving control signal. The first control element comprises but is not limited to a PWM controller. Exemplarily, a driving pin (DRV pin) of the PWM controller is connected to the driving control signal TFDRV. In some embodiments, to improve the conversion efficiency, the first control element can generally adopt a quasi-resonant or active clamp controller.

[0042] The gate of the control transistor 4011 is configured to receive the driving control signal TFDRV. The drain of the control transistor 4011 is connected to the primary side power loop of the flyback circuit 406. The source of the control transistor 4011 is grounded.

[0043] When the driving control signal TFDRV is at a first level, the control transistor 4011 is in a conducting state, and the four groups of secondary side windings 407 are all in a cut-off state. When the driving control signal TFDRV is at a second level, the control transistor 4011 is in a cut-off state, and the four groups of secondary side windings 407 are all in a conducting state.

[0044] Please continue to refer to Figure 5 In some embodiments, the control module 401 can further comprise at least one of the resistors 4012, 4013 and 4014.

[0045] In the embodiment, the target battery cell is a battery cell that needs to be balanced, which comprises at least one of the battery cells 405. It is assumed that Figure 4 The battery cells 405 in the figure from top to bottom are battery cell A, battery cell B and battery cell C. If it is desired to balance the battery cell A and the battery cell B, the target battery cell comprises the battery cell A and the battery cell B.

[0046] The target synchronous rectification module is the synchronous rectification module 403 corresponding to the target battery cell, that is, the target synchronous rectification module is the synchronous rectification module 403 connected to the target battery cell. Similarly, the channel selection module 404 corresponding to the target synchronous rectification module is the channel selection module 404 connected to the target synchronous rectification module.

[0047] Further, the channel selection module 404 corresponding to the target synchronous rectification module is configured to, in response to the enable signal of the target battery cell, turn on a power supply path between the power supply module 402 and the target synchronous rectification module, so that the power supply module 402 supplies power to the target synchronous rectification module through the power supply path, to control the target synchronous rectification module to be in a working state.

[0048] The power supply module 402 is configured to supply power to the synchronous rectification module 403, which comprises but is not limited to any form of current source or voltage source.

[0049] The enable signal is used to indicate which battery cell 405 needs to be balanced. It can be a signal of any logic state or voltage state. For example, the enable signal can be a high-level signal. Alternatively, the enable signal can be a signal initiated by a user through an interactive element such as a key switch, or a signal generated by a second control element such as a microcontroller unit (MCU), although this embodiment does not limit this.

[0050] Optionally, the channel selection module 404 corresponding to the target synchronous rectifier module may include a switching element, so that in response to an enable signal of the target battery cell, the power supply path between the power supply module 402 and the target synchronous rectifier module is turned on through the switching element in the channel selection module 404. The switching element includes, but is not limited to, an insulated gate bipolar transistor (IGBT), a metal-oxide-semiconductor field-effect transistor (MOSFET), and a physical switch.

[0051] For example, please refer to Figure 4 ,remember Figure 4 The synchronous rectification modules 403 in the embodiment are synchronous rectification module A, synchronous rectification module B and synchronous rectification module C from top to bottom. Figure 4 The channel selection module 404 is composed of channel selection module A, channel selection module B, and channel selection module C from top to bottom. If the target battery cells include battery cells A and B, channel selection module A will receive an enable signal, and then channel selection module A will conduct the power supply path A between the power supply module 402 and the synchronous rectification module A. The power supply module 402 supplies power to the synchronous rectification module A through the power supply path A. At this time, the synchronous rectification module A will be in a working state. The same is true for battery cell B. The synchronous rectification module B connected to battery cell B will also be in a working state. However, since the channel selection module A connected to battery cell C does not receive an enable signal, the synchronous rectification module A connected to battery cell C will be in a non-working state.

[0052] Furthermore, the target synchronous rectification module is used to conduct the charging path between the target battery cell and the secondary winding 407 corresponding to the target battery cell when it is in working state and the secondary winding 407 in the flyback circuit 406 is in the on state, so that the secondary winding 407 corresponding to the target battery cell charges the target battery cell through the charging path.

[0053] Optionally, the target synchronous rectifier module may include at least one switching element. Furthermore, when the secondary winding 407 in the flyback circuit 406 is in the on state and the target synchronous rectifier module is in the working state, the target synchronous rectifier module conducts the charging path between the target battery cell and the corresponding secondary winding 407 through its own switching element.

[0054] Continuing with the example where the target cells include cell A and cell B, Figure 4 The secondary winding 407 is composed of the secondary winding A, secondary winding B, and secondary winding C from top to bottom. Assume that the secondary winding 407 is already in the on state. Then, since the synchronous rectifier module A is in the working state, the synchronous rectifier module A will conduct the charging path A between the secondary winding A and the battery cell A, and the secondary winding A will charge the battery cell A through the charging path A. Similarly, since the synchronous rectifier module B is in the working state, the synchronous rectifier module B will conduct the charging path B between the secondary winding B and the battery cell B, and the secondary winding B will charge the battery cell B through the charging path B. Since the synchronous rectifier module B is in the non-working state, the battery cell C will not be charged. In this way, the balance of the battery cells A and B can be achieved.

[0055] The balancing circuit 400 includes a control module 401, a power supply module 402, at least one synchronous rectifier module 403, and a channel selection module 404 corresponding to each synchronous rectifier module 403. Each synchronous rectifier module 403 is connected to a corresponding battery cell 405 and a corresponding secondary winding 407 in a flyback circuit 406, and the channel selection module 404 is also connected to the power supply module 402 and the corresponding synchronous rectifier module 403. Furthermore, the control module 401 is capable of outputting a drive control signal to control the secondary winding 407 in the flyback circuit 406 to be in an off state when the drive control signal is at a first level, and to control the secondary winding 407 in the flyback circuit 406 to be in an on state when the drive control signal is at a second level. Since the target battery cell includes at least one of the battery cells 405, the target synchronous rectification module is the synchronous rectification module 403 corresponding to the target battery cell, and the channel selection module 404 corresponding to the target synchronous rectification module is used to respond to the enable signal of the target battery cell, turn on the power supply path between the power supply module 402 and the target synchronous rectification module, so that the power supply module 402 supplies power to the target synchronous rectification module through the power supply path to control the target synchronous rectification module to be in a working state, and the target synchronous rectification module is used to turn on the charging path between the target battery cell and the secondary winding 407 corresponding to the target battery cell when it is in a working state and the secondary winding 407 in the flyback circuit 406 is in a conductive state, so that the secondary winding 407 corresponding to the target battery cell charges the target battery cell through the charging path. Therefore, the target battery cell that needs to be balanced can be independently selected through the enable signal, and the target battery cell is balanced through the secondary winding 407 in the flyback circuit 406, which has good flexibility.

[0056] Figure 6 FIG. 1 is a schematic diagram of a synchronous rectification module in one embodiment, as shown in FIG. Figure 6 As shown, in an exemplary embodiment, optionally, each synchronous rectifier module 403 includes a rectifier control unit 4031 and a first switch unit 4032 connected to each other. In addition, for each synchronous rectifier module 403, the secondary winding 407 corresponding to the synchronous rectifier module 403 is connected to the battery cell 405 corresponding to the synchronous rectifier module 403 through the first switch unit 4032, and the rectifier control unit 4031 is also connected to the corresponding channel selection module 404.

[0057] In this embodiment, the channel selection module 404 corresponding to the target synchronous rectification module is used to respond to the enable signal to turn on the power supply path between the power supply module 402 and the rectification control unit 4031 in the target synchronous rectification module to control the rectification control unit 4031 in the target synchronous rectification module to be in a working state.

[0058] Optionally, after the channel selection module 404 corresponding to the target synchronous rectification module receives the enable signal, it can control its own switching element to be in the on state, so as to turn on the power supply path between the power supply module 402 and the rectification control unit 4031 in the target synchronous rectification module, so that the rectification control unit 4031 in the target synchronous rectification module is in a working state.

[0059] Furthermore, the rectifier control unit 4031 is configured to, when in operation and the secondary winding 407 in the flyback circuit 406 is in an on state, conduct the charging path through the first switch unit 4032. Optionally, when the secondary winding 407 is in an on state and the rectifier control unit 4031 is in operation, the rectifier control unit 4031 may control the first switch unit 4032 to be in an on state. When the first switch unit 4032 is in an on state, the charging path between the corresponding secondary winding 407 and the battery cell 405 is conducted.

[0060] In the above embodiment, the first switch unit 4032 is triggered to turn on the charging path only when the target battery cell is selected and the secondary winding 407 is in the on state, thereby improving the accuracy of balancing. Moreover, by turning on the charging path through the first switch unit 4032, the efficiency of balancing can also be improved.

[0061] Figure 7 FIG. 1 is a schematic diagram of another synchronous rectification module in an embodiment, as shown in FIG. Figure 7 As shown, in an exemplary embodiment, optionally, the rectification control unit 4031 includes a voltage stabilizing element U1 , and the first switching unit 4032 includes a first transistor Q1 .

[0062] Figure 7 The synchronous rectification module 403 connected to the first secondary winding 407 and the first battery cell 405 is illustrated. It is understandable that the other synchronous rectification modules 403 are similarly connected.

[0063] like Figure 7 As shown, the main power input pin of the voltage regulator U1 (also Figure 7 The VDD pin in the power supply module 402 is connected to the power input pin of the voltage stabilizing element U1 (that is, Figure 7 The VD pin in the figure is connected to the negative electrode of the corresponding secondary winding 407 (for example, the negative electrode S1- of the first set of secondary windings 407) and the drain of the first transistor Q1, and the output pin of the voltage stabilizing element U1 (that is, Figure 7The negative electrode of the corresponding battery cell 405 (for example, the negative electrode CELL0 of the first group of battery cells 405) is connected to the main power input pin of the voltage stabilizing element U1, the gate driving pin (i.e., the VG pin in the figure) of the voltage stabilizing element U1 is connected to the gate of the first transistor Q1, the source of the first transistor Q1 is connected to the negative electrode of the corresponding battery cell 405, and the positive electrode of the battery cell 405 (for example, the positive electrode CELL1 of the first group of battery cells 405) is connected to the positive electrode of the corresponding secondary winding 407 (for example, the positive electrode S1+ of the first group of secondary windings 407).

[0064] Please continue to refer to Figure 7 When the target synchronous rectification module is in the working state and the secondary winding 407 is in the conducting state, the output pin of the voltage stabilizing element U1 in the target synchronous rectification module drives the first transistor Q1 to be in the conducting state, and the voltage across the secondary winding 407 is close to the voltage across the battery cell 405, so as to charge the corresponding battery cell 405 by the output voltage of the secondary winding 407.

[0065] In the above embodiment, since the main power input pin of the voltage stabilizing element U1 is connected to the power supply module 402, the power input pin of the voltage stabilizing element U1 is connected to the negative electrode of the corresponding secondary winding 407 and the drain of the first transistor Q1, the output pin of the voltage stabilizing element U1 is connected to the negative electrode of the corresponding battery cell 405, the gate driving pin of the voltage stabilizing element U1 is connected to the gate of the first transistor Q1, the source of the first transistor Q1 is connected to the negative electrode of the corresponding battery cell 405, and the positive electrode of the battery cell 405 is connected to the positive electrode of the corresponding secondary winding 407, therefore, by the voltage stabilizing element U1 and the first transistor Q1, the charging path can be efficiently turned on when equalization is needed.

[0066] Please continue to refer to Figure 7 In an exemplary embodiment, the first switching unit 4032 further includes a second transistor Q2. The gate of the second transistor Q2 is connected to the gate of the first transistor Q1, the drain of the second transistor Q2 is connected to the source of the first transistor Q1 and the positive electrode of the corresponding secondary winding 407, and the source of the second transistor Q2 is connected to the negative electrode of the corresponding battery cell 405.

[0067] Please continue to refer to Figure 7 When the target synchronous rectification module is in the working state and the secondary winding 407 is in the conducting state, the output pin of the voltage stabilizing element U1 in the target synchronous rectification module drives the first transistor Q1 and the second transistor Q2 to be in the conducting state, so as to charge the corresponding battery cell 405 by the output voltage of the secondary winding 407. Moreover, when the secondary winding 407 is in the cut-off state or the synchronous rectification module 403 is in the non-working state, the second transistor Q2 can also prevent the battery cell 405 from discharging to the secondary winding 407, so as to ensure that the battery cell 405 does not leak electricity.

[0068] In the above embodiment, since the first switch unit 4032 further comprises the second transistor Q2, and the gate of the second transistor Q2 is connected with the gate of the first transistor Q1, the drain of the second transistor Q2 is connected with the source of the first transistor Q1 and the positive pole of the corresponding secondary winding 407 respectively, and the source of the second transistor Q2 is connected with the negative pole of the corresponding battery cell 405, thus the second transistor Q2 can also prevent the battery cell 405 from discharging to the secondary winding 407, and the reliability of the balancing circuit 400 is improved.

[0069] Please continue to refer to Figure 7 In one embodiment, optionally, each synchronous rectification module 403 can further comprise at least one of the following: (1) a driving resistor 701; the driving resistor 701 is connected with the gate driving pin of the voltage stabilizing element U1 and the gate of the second transistor Q2 respectively. (2) a pull-down resistor 702; the pull-down resistor 702 is connected with the gate driving pin of the voltage stabilizing element U1 and the source of the second transistor Q2 respectively. (3) a capacitor 703; the capacitor 703 is connected with the feedback pin (i.e. the REG pin) of the voltage stabilizing element U1 and the negative pole of the battery cell 405 respectively. (4) a capacitor 704; the capacitor 704 is connected with the positive pole of the battery cell 405 and the negative pole of the battery cell 405 respectively. (5) a capacitor 705; the capacitor 705 is connected with the positive pole of the battery cell 405 and the negative pole of the battery cell 405 respectively. (6) a fuse element 706; the fuse element 706 is connected with the positive pole of the secondary winding 407 and the positive pole of the battery cell 405 respectively. (7) a capacitor 707; the capacitor 707 is connected with the positive pole of the secondary winding 407 and the source of the first transistor Q1 respectively. (8) an energy consumption resistor 708; the energy consumption resistor 708 is connected with the positive pole of the secondary winding 407 and the source of the first transistor Q1 respectively. Figure 7

[0070] Please continue to refer to Figure 7 In one embodiment, in the case that the secondary winding 407 is in the conducting state, if the voltage stabilizing element U1 is powered, the target synchronous rectification module works normally, the 1 pin (i.e. the VG pin) of the voltage stabilizing element U1 can drive the first transistor Q1 and the second transistor Q2 to be in the conducting state through the driving resistor 701, the winding voltage (hereinafter referred to as winding voltage) of the secondary winding is close to the battery cell voltage (hereinafter referred to as battery cell voltage) of the corresponding battery cell, and the corresponding battery cell is charged by the winding voltage.

[0071] If the voltage stabilizing element U1 is not powered, the first transistor Q1 and the second transistor Q2 are in the cut-off state, at this time the current must flow through the body diode of the first transistor Q1 and the second transistor Q2. The winding voltage is higher than the battery cell voltage of the corresponding battery cell. Assuming that the conduction voltage drop of the body diode is Vd, the winding voltage is equal to the sum of the battery cell voltage of the corresponding battery cell and twice Vd.

[0072] ​When the secondary winding is in the off state or the power supply is not working, the second transistor Q2 prevents the battery from discharging to the energy dissipation resistor 708, ensuring that the battery does not leak.

[0073] Assuming that the voltage across multiple battery cells is completely consistent. When any one of the secondary windings is in a synchronous rectification state, the secondary voltage is equal to the corresponding battery cell voltage. According to the characteristics of the transformer, the output voltage of the secondary winding in the non-synchronous rectification state will also be synchronously clamped to the battery cell voltage. Due to the conduction voltage of the body diode, in theory, this secondary winding will not be able to output current to the corresponding battery cell. In fact, there is always leakage inductance in the transformer, and if no measures are taken, the leakage energy will be transmitted to the battery cell. Therefore, by reasonably setting the resistance value of the energy dissipation resistor 708 and the capacitance value of the capacitor 707, the leakage energy can be absorbed to ensure that no energy is transmitted to the battery cell. For example, the product of the capacitance value of the capacitor 707 and the voltage difference between the leakage inductance can be equal to the square of the leakage inductance divided by the resistance value of the energy dissipation resistor 708.

[0074] In this way, through the above design, only the secondary winding in the synchronous rectification state can output, and the secondary winding in the non-synchronous rectification state cannot output, thereby achieving charging balance for specific battery cells.

[0075] Figure 8 For another embodiment of a synchronous rectification module, as shown in Figure 8 In an exemplary embodiment, the rectification control unit 4031 includes a voltage stabilizing element U1, and the first switching unit 4032 includes a third transistor Q3 and a fourth transistor Q4.

[0076] Similarly, Figure 8 The synchronous rectification module 403 connected to the first secondary winding 407 and the first battery cell 405 is shown, and the other synchronous rectification modules 403 are the same. As shown in Figure 8 The main power input pin of the voltage stabilizing element U1 is connected to the power supply module 402, the power input pin of the voltage stabilizing element U1 is connected to the negative electrode of the corresponding secondary winding 407 and the drain of the third transistor Q3, the gate of the third transistor Q3 is connected to the gate drive pin of the voltage stabilizing element U1, the source of the third transistor Q3 is connected to the drain of the fourth transistor Q4 and the output pin of the voltage stabilizing element U1, the gate of the fourth transistor Q4 is connected to the power supply module 402, the source of the fourth transistor Q4 is connected to the negative electrode of the corresponding battery cell 405, and the positive electrode of the battery cell 405 is connected to the positive electrode of the corresponding secondary winding 407.

[0077] Please continue to refer to Figure 8In the case that the target synchronous rectification module is in the working state and the secondary winding 407 is in the conducting state, the output pin of the voltage stabilizing element U1 in the target synchronous rectification module will drive the third transistor Q3 to be in the conducting state, and the fourth transistor Q4 will be in the conducting state due to the existence of the power supply module 402, so as to charge the corresponding battery cell 405 by the output voltage of the secondary winding 407. Figure 8 The principle of the above embodiment is similar to Figure 7 that of the above embodiment, which will not be repeated here.

[0078] In the above embodiment, since the main power input pin of the voltage stabilizing element U1 is connected to the power supply module 402, the power input pin of the voltage stabilizing element U1 is connected to the negative pole of the corresponding secondary winding 407 and the drain of the third transistor Q3, the gate of the third transistor Q3 is connected to the gate drive pin of the voltage stabilizing element U1, the source of the third transistor Q3 is connected to the drain of the fourth transistor Q4 and the output pin of the voltage stabilizing element U1, the gate of the fourth transistor Q4 is connected to the power supply module 402, the source of the fourth transistor Q4 is connected to the negative pole of the corresponding battery cell 405, and the positive pole of the battery cell 405 is connected to the positive pole of the corresponding secondary winding 407, therefore, through the voltage stabilizing element U1, the third transistor Q3 and the fourth transistor Q4, the charging path can also be efficiently turned on when equalization is needed.

[0079] Please continue to refer to Figure 8 In one embodiment, optionally, each synchronous rectification module 403 can further include at least one of the following: (1) a drive resistor 801; the drive resistor 801 is respectively connected to the gate drive pin of the voltage stabilizing element U1 and the gate of the third transistor Q3. (2) a pull-down resistor 802; the pull-down resistor 802 is respectively connected to the gate drive pin of the voltage stabilizing element U1 and the source of the third transistor Q3. (3) a resistor 803; the resistor 806 is respectively connected to the power supply and the gate of the fourth transistor Q4. (4) a resistor 804; the resistor 804 is respectively connected to the gate and the source of the fourth transistor Q4. (5) a resistor 805; the resistor 805 is respectively connected to the positive pole of the battery cell 405 and the drain of the fourth transistor Q4.

[0080] Figure 9 For a schematic diagram of one constant current module in an embodiment, as Figure 9 shown, in one exemplary embodiment, the equalization circuit 400 further includes a constant current module 408, and the constant current module 408 is respectively connected to the flyback circuit 406 and the control module 401.

[0081] Among them, the constant current module 408 is used to obtain the primary side detection parameter of the flyback circuit 406, denoted as CS. Please refer to Figure 5Optionally, the primary side detection parameter of the flyback circuit 406 can be obtained through the resistor 4014. The primary side detection parameter includes but is not limited to the detection current or the detection voltage. Exemplarily, the CS can also be understood as an input current sampling signal, which can be connected to the CS current detection pin of the PWM controller.

[0082] Further, the constant current module 408 compares the primary side detection parameter with the target constant current parameter. The target constant current parameter is the constant current parameter taken as the reference of the primary side detection parameter, which can be a preset constant current parameter.

[0083] Further, in the case that the primary side detection parameter is greater than the target constant current parameter, the constant current module 408 can control the duty cycle of the drive control signal to be a first preset value until the primary side detection parameter is less than or equal to the target constant current parameter, so that the charging parameter of the target electric core corresponding to the secondary side winding 407 is within the preset charging parameter range. The first preset value is used to reduce the duty cycle of the drive control signal, which can be a number close to 0, for example, 0. The charging parameter includes but is not limited to the charging current (which can also be referred to as the balancing current) of the target electric core corresponding to the secondary side winding 407. The preset charging parameter range can be set according to actual needs, which is not limited in the embodiment.

[0084] Exemplarily, taking the primary side detection parameter including the primary side detection current as an example, when the control transistor 4011 is in the conducting state, the constant current module 408 obtains the primary side detection current of the flyback circuit 406, and compares the primary side detection current with the target constant current parameter. If the primary side detection current is less than the target constant current parameter, the duty cycle of the drive control signal can be increased, and if the primary side detection current is greater than the target constant current parameter, the duty cycle of the drive control signal can be set to 0 until the primary side detection current is less than or equal to the target constant current parameter. Through continuous feedback adjustment, the primary side detection current can be maintained around the target constant current parameter. In this process, since the primary side detection current is maintained around the target constant current parameter, the charging parameter of the target electric core corresponding to the secondary side winding 407 is also within the preset charging parameter range.

[0085] In the above embodiment, since the constant current module 408 can obtain the primary side detection parameter of the flyback circuit 406, and in the case that the primary side detection parameter is greater than the target constant current parameter, the duty cycle of the drive control signal is controlled to be a first preset value until the primary side detection parameter is less than or equal to the target constant current parameter, so that the charging parameter of the target electric core corresponding to the secondary side winding 407 is within the preset charging parameter range, achieving the effect of constant current balancing, and the balancing process is controllable, which has high reliability.

[0086] Please continue to refer to Figure 9In an example embodiment, the optional constant current module 408 comprises a comparison unit 4081 and a gear adjustment unit 4082. The non-inverting input of the comparison unit 4081 is connected to the gear adjustment unit 4082, and the inverting input of the comparison unit 4081 is configured to receive the primary side detection parameter. The output of the comparison unit 4081 is connected to the control module 401.

[0087] In the present embodiment, the gear adjustment unit 4082 is configured to determine a target constant current parameter corresponding to the gear control signal in response to the gear control signal. The gear control signal (denoted as C SET) is configured to set the target constant current parameter. It can be understood that the gear control signal can be a signal initiated by a user through a key switch or other interactive element, or a signal generated by a microcontroller or other second control element, and the present embodiment is not limited thereto.

[0088] Optionally, the gear control signal can indicate the level of the target constant current parameter, and different levels of the target constant current parameter are different. For example, when the gear adjustment unit 4082 is a high-level signal, it corresponds to a larger target constant current parameter, and when the gear adjustment unit 4082 is a low-level signal, it corresponds to a smaller target constant current parameter. Further optionally, the gear adjustment unit 4082 can switch different target constant current parameters through a relay.

[0089] Further, the comparison unit 4081 is configured to obtain the primary side detection parameter, and control the duty cycle of the drive control signal to be a first preset value when the primary side detection parameter is greater than the target constant current parameter corresponding to the gear control signal, until the primary side detection parameter is less than or equal to the target constant current parameter.

[0090] In the above embodiment, the corresponding target constant current parameter can be flexibly set by the gear adjustment unit 4082, which not only makes the balancing process controllable, but also adapts to different battery states and charging demands, thereby expanding the application scenarios.

[0091] Please continue to refer to Figure 9 In an example embodiment, the optional gear adjustment unit 4082 comprises a first switch subunit 4082a and a resistance subunit 4082b. The resistance subunit 4082b is connected to the first switch subunit 4082a and the non-inverting input of the comparison unit 4081, respectively.

[0092] In the present embodiment, the first switch subunit 4082a is configured to receive the gear control signal and adjust the resistance value of the resistance subunit 4082b based on the gear control signal, so as to determine the target constant current parameter corresponding to the gear control signal based on the resistance value of the resistance subunit 4082b.

[0093] Optionally, the first switch subunit 4082a can be a relay. Under different gear control signals, the relay selects the resistance value of different resistance subunits 4082b, and generates the target constant current parameter corresponding to the gear control signal based on the resistance value of the different resistance subunits 4082b. The resistance subunit 4082b can be implemented by a sliding resistor, a series adjustable resistor, a manually adjustable resistor, etc., and the present embodiment is not limited in this regard.

[0094] In the above embodiment, the gear control signal is received by the first switch subunit 4082a, and the resistance value of the resistance subunit 4082b is adjusted based on the gear control signal. In this way, based on the resistance value of the resistance subunit 4082b, the target constant current parameter corresponding to the gear control signal can be efficiently determined, and excessive cost is not increased.

[0095] Figure 10 For another schematic diagram of a constant current module in an embodiment, as shown in FIG. 4B, in an example embodiment, the first switch subunit 4082a includes a fifth transistor Q5, and the resistance subunit 4082b includes a first resistor 1001 and a second resistor 1002. Figure 10

[0096] The gate of the fifth transistor Q5 is configured to receive the gear control signal, the source of the fifth transistor Q5 is grounded, and the drain of the fifth transistor Q5 is connected to the first end of the first resistor 1001. The second end of the first resistor 1001 is connected to the first end of the second resistor 1002. The second end of the second resistor 1002 is connected to the non-inverting input of the comparison unit 4081 and the second end of the first resistor 1001, respectively. The first end of the second resistor 1002 is also connected to a preset power supply (i.e., VCC in FIG. 4B). FB can represent the feedback pin of the PWM controller. Figure 10

[0097] When the gear control signal is high, the fifth transistor Q5 is in an on state, the first resistor 1001 and the second resistor 1002 are in parallel, the voltage at the non-inverting input of the comparison unit 4081 is low, and the target constant current parameter decreases. Similarly, when the gear control signal is low, the fifth transistor Q5 is in an off state, and a target constant current parameter is also obtained.

[0098] It should be noted that, Figure 10 Only one optional form is shown. By adding multiple fifth transistors Q5 and second resistors 1002, multiple target constant current parameters can be obtained.

[0099] ​​In the above embodiment, since the gate of the fifth transistor Q5 is configured to receive the gear control signal, the source of the fifth transistor Q5 is grounded, the drain of the fifth transistor Q5 is connected to the first end of the first resistor 1001, the second end of the first resistor 1001 is connected to the first end of the second resistor 1002, the second end of the second resistor 1002 is connected to the non-inverting input of the comparison unit 4081 and the second end of the first resistor 1001 respectively, and the first end of the second resistor 1002 is further connected to the preset power supply, therefore, the connection state between the first resistor 1001 and the second resistor 1002 can be flexibly adjusted by the state of the fifth transistor Q5, so as to obtain different target constant current parameters.

[0100] Please continue to refer to Figure 10 In one embodiment, optionally, the constant current module 408 can further include at least one of the following: (1) a resistor 1003; one end of the resistor 1003 is configured to receive the gear control signal, and the other end of the resistor 1003 is connected to the gate of the fifth transistor Q5. (2) a resistor 1004; one end of the resistor 1004 is connected to the gate of the fifth transistor Q5, and the other end of the resistor 1004 is grounded. (3) a resistor 1005; the resistor 1005 is connected to the second resistor 1002 and the preset power supply respectively. (4) a capacitor 1006; one end of the capacitor 1006 is connected to the second resistor 1002 and the resistor 1005 respectively, and the other end of the capacitor 1006 is grounded. (5) a resistor 1007; one end of the resistor 1007 is configured to receive the primary side detection parameter, and the other end of the resistor 1007 is connected to the inverting input of the comparison unit 4081. (6) a resistor 1008; one end of the resistor 1008 is configured to receive the primary side detection parameter, and the other end of the resistor 1008 is connected to the inverting input of the comparison unit 4081. (7) a capacitor 1009; one end of the capacitor 1009 is configured to receive the primary side detection parameter, and the other end of the capacitor 1009 is connected to the inverting input of the comparison unit 4081. (8) a resistor 1010; the resistor 1010 is connected to the inverting input and the output of the comparison unit 4081 respectively. (9) a capacitor 1011; the capacitor 1011 is connected to the inverting input and the output of the comparison unit 4081 respectively. (10) a capacitor 1012; the capacitor 1012 is connected to the inverting input and the output of the comparison unit 4081 respectively. (11) a diode 1013; the negative electrode of the diode 1013 is connected to the output of the comparison unit 4081, and the positive electrode of the diode 1013 is connected to the output of the constant current module 408. (12) a resistor 1014; the resistor 1014 is connected to the positive electrode of the diode 1013.

[0101] Please continue to refer to Figure 10, the resistance 1007, the resistance 1008, the capacitor 1009, the resistance 1010, the capacitor 1012, the capacitor 1011 jointly constitute a feedback compensation network. The output of the comparison unit 4081 is connected to the feedback pin of the PWM controller through the diode 1013 and the resistance 1014. If the original side detection parameter is greater than the target constant current parameter, the comparison unit 4081 outputs low level, the FB of the PWM controller is pulled low through the diode 1013 and the resistance 1014, and the driving pin of the PWM controller stops pulsing, until the original side detection parameter is less than or equal to the target constant current parameter, the comparison unit 4081 outputs high level, the diode 1013 is reverse cut-off, the FB of the PWM controller is normal, and the driving pin of the PWM controller normally pulses.

[0102] In some embodiments, on the basis of Figure 10 , the constant current module 408 can further include a feedback compensation network, and by adjusting the parameters of the feedback compensation network, the equalization circuit can be made to work more stably in the input constant current state.

[0103] Figure 11 For a schematic diagram of a channel selection module in one embodiment, as Figure 11 shown, in an exemplary embodiment, each channel selection module 404 includes a second switch unit 4042 and an optocoupler unit 4041. Wherein, the optocoupler unit 4041 is connected with the second switch unit 4042 and the power supply module 402 respectively.

[0104] In the present embodiment, the second switch unit 4042 is used to receive the channel control signal of the xth battery cell 405, denoted as Cx_syn, for example, C1_syn is high level, indicating that the first battery cell A needs to be equalized, C2_syn is high level, indicating that the second battery cell B needs to be equalized, and so on.

[0105] Wherein, the channel control signal includes an enable signal. Further, the second switch unit 4042 will control the optocoupler unit 4041 to be in a conducting state based on the enable signal after receiving the enable signal. That is, the second switch unit 4042 will turn on the corresponding optocoupler unit 4041 after receiving the enable signal.

[0106] Further, the optocoupler unit 4041 is used to turn on the corresponding power supply path in the conducting state. Continuing the above example, the second switch unit 4042 in the channel selection module A will turn on the optocoupler unit 4041 in itself after receiving the enable signal of the battery cell A, so as to turn on the power supply path A between the power supply module 402 and the synchronous rectification module A through the optocoupler unit 4041 in itself.

[0107] In the above embodiment, since the light coupling unit 4041 is controlled to be turned on by the enable signal and the second switch unit 4042, the channel control is accurate and the reliability and stability of the channel selection module 404 are enhanced.

[0108] Figure 12 Fig. 4B shows a schematic diagram of another channel selection module in an embodiment, as shown in an example embodiment, the second switch unit 4042 includes a sixth transistor Q6, and the light coupling unit 4041 includes a diode subunit (as shown in the 1st pin and the 2nd pin of the light coupling unit 4041 in Fig. 4B) and a triode subunit (as shown in the 3rd pin and the 4th pin of the light coupling unit 4041 in Fig. 4B). Figure 12 Figure 12 Figure 12

[0109] The base of the sixth transistor Q6 is used to receive the enable signal, the emitter of the sixth transistor Q6 is grounded, and the collector of the sixth transistor Q6 is connected to the negative electrode of the diode subunit. The positive electrode of the diode subunit is connected to the input power supply 409, and the triode subunit is connected to the power supply module 402. That is, after the sixth transistor Q6 is turned on, the diode subunit in the light coupling unit 4041 is controlled to be turned on, and then the triode subunit in the light coupling unit 4041 is controlled to be turned on, so that the entire light coupling unit 4041 is turned on. The input power supply 409 can include, but is not limited to, a battery total voltage or an external DC power supply.

[0110] It can be understood that, Figure 12 Fig. 4B shows a schematic diagram of another channel selection module in an embodiment, as shown in an example embodiment, the second switch unit 4042 includes a sixth transistor Q6, and the light coupling unit 4041 includes a diode subunit (as shown in the 1st pin and the 2nd pin of the light coupling unit 4041 in Fig. 4B) and a triode subunit (as shown in the 3rd pin and the 4th pin of the light coupling unit 4041 in Fig. 4B). Figure 12

[0111] Continuing to take the synchronous rectification module 403 of the first battery cell 405 as an example, the base of the sixth transistor Q6 is used to receive the channel control signal C1-syn of the battery cell A. When C1-syn is a high-level signal, that is, the base of the sixth transistor Q6 receives the enable signal of the battery cell A, the sixth transistor Q6 is turned on, and the light coupling unit 4041 U1 is also turned on, so that the power supply module 402 supplies power to the synchronous rectification module A, and the synchronous rectification module A is in a working state.

[0112] ​​​​In the above embodiment, since the base of the sixth transistor Q6 is configured to receive the enable signal, the emitter of the sixth transistor Q6 is grounded, the collector of the sixth transistor Q6 is connected to the negative electrode of the diode subunit, the positive electrode of the diode subunit is connected to the input power supply 409, and the triode subunit is connected to the power supply module 402, the sixth transistor Q6 can quickly respond to the enable signal, realize electrical isolation with the optical coupling unit 4041, have strong anti-interference ability, and can also efficiently and accurately control the on-off of the power supply path.

[0113] Please continue to refer to Figure 12 In one embodiment, the channel selection module 404 can further include at least one of the resistors 1201, 1202, and 1203.

[0114] In one exemplary embodiment, the channel selection module 404 corresponding to the target synchronous rectification module is further configured to, in response to a stop enable signal of the target battery cell, disconnect the power supply path between the power supply module 402 and the target synchronous rectification module, thereby disconnecting the charging path between the target battery cell and the corresponding secondary winding 407 of the target battery cell to stop charging the target battery cell.

[0115] In the embodiment, the channel control signal further includes a stop enable signal. The stop enable signal is used to stop balancing the battery cells 405. The stop enable signal and the enable signal are two different logic states or voltage states. For example, the enable signal can be a low-level signal. Alternatively, the stop enable signal can be a signal initiated by a user through a key switch or other interactive element, or a signal generated by a second control element such as a microcontroller unit (MCU), and the embodiment is not limited thereto.

[0116] In some embodiments, the stop enable signal can also be generated when the balancing condition is met. The balancing condition includes, but is not limited to, the difference between the state of charge (SOC) of each battery cell 405 being less than a preset difference. Further alternatively, the balancing current of the target battery cell during charging can be determined, and the balancing time required to meet the balancing condition can be determined according to the current SOC and the balancing current of each target battery cell, and the stop enable signal can be automatically generated when the balancing time is reached.

[0117] Alternatively, the channel selection module 404 corresponding to the target synchronous rectification module can disconnect the power supply path between the power supply module 402 and the target synchronous rectification module by the switching element in the channel selection module 404 when the stop enable signal of the target battery cell is received.

[0118] Further, the second switch unit 4042 is configured to receive a stop enable signal and control the optocoupler unit 4041 to be in an off state based on the stop enable signal. In this way, the optocoupler unit 4041 is configured to disconnect the corresponding power supply path when in the off state.

[0119] Please continue to refer to Figure 12 When the C1-syn signal is at a low level, i.e., the base of the sixth transistor Q6 receives the stop enable signal of the battery A, the sixth transistor Q6 is in an off state, the optocoupler unit 4041U1 is also in an off state, the power supply module 402 stops supplying power to the synchronous rectification module A, and the synchronous rectification module A is in a non-working state.

[0120] In this way, the balancing can also be stopped in time through the stop enable signal, and the reliability of the balancing is improved.

[0121] The synchronous rectification module usually needs a working voltage of 5V or above, and the output voltage of each battery is not more than 4.2V (the maximum voltage of a ternary lithium battery), so the synchronous rectification module needs to be additionally powered by a power supply. In the related art, an additional power supply winding is usually added to the transformer, but if this method is used in the present application, multiple power supply windings need to be added, which is relatively high in cost. Therefore, the present application provides another power supply module with relatively low cost.

[0122] Figure 13 A schematic diagram of a power supply module in one embodiment is shown in FIG. 4A. Figure 13 As shown in FIG. 4A, in an exemplary embodiment, the power supply module 402 includes a third switch unit 4021, a fourth switch unit 4022, and at least one first energy storage unit 4023.

[0123] The third switch unit 4021 is connected to the input power supply 409 and the fourth switch unit 4022, respectively. The first end of each first energy storage unit 4023 is connected to the third switch unit 4021 and the fourth switch unit 4022, respectively, and the second end of each first energy storage unit 4023 is connected to the corresponding synchronous rectification module 403. It should be noted that the number of first energy storage units 4023 corresponds to the number of batteries 405.

[0124] In this embodiment, the third switch unit 4021 is configured to respond to a drive control signal. When the drive control signal is at a first level, the third switch unit 4021 turns on a first path between the input power supply 409 and each first energy storage unit 4023, so that the input power supply 409 charges the first energy storage unit 4023 through the first path, and the first energy storage unit 4023 supplies power to the corresponding synchronous rectification module 403 based on the output voltage of the first energy storage unit 4023.

[0125] The fourth switch unit 4022 is configured to, in response to the driving control signal, disconnect the first path and turn on the second path between the first energy storage unit 4023 and the ground terminal to discharge the energy of each first energy storage unit 4023 and stop supplying power to the corresponding synchronous rectification module 403 when the driving control signal is at the first level.

[0126] For example, when the driving control signal is at the first level, the third switch unit 4021 is in the on state, the fourth switch unit 4022 is in the off state, the first path between the input power supply 409 and each first energy storage unit 4023 is turned on by the third switch unit 4021, and the first energy storage unit 4023 is in the charging state. When the driving control signal is at the second level, the third switch unit 4021 is in the off state, the fourth switch unit 4022 is in the on state, the second path between the first energy storage unit 4023 and the ground terminal is turned on by the fourth switch unit 4022, and the first energy storage unit 4023 is in the discharging state.

[0127] In the above embodiment, since the third switch unit 4021 can, in response to the driving control signal, turn on the first path between the input power supply 409 and each first energy storage unit 4023 to charge the first energy storage unit 4023 through the first path by the input power supply 409 and supply power to the corresponding synchronous rectification module 403 based on the output voltage of the first energy storage unit 4023 when the driving control signal is at the first level, and the fourth switch unit 4022 can, in response to the driving control signal, disconnect the first path and turn on the second path between the first energy storage unit 4023 and the ground terminal to discharge the energy of each first energy storage unit 4023 and stop supplying power to the corresponding synchronous rectification module 403 when the driving control signal is at the first level, the third switch unit 4021 and the fourth switch unit 4022 can be efficiently and accurately controlled by the driving control signal, the charging and discharging states of the first energy storage unit 4023 can be quickly switched, the stable power supply of the synchronous rectification module 403 can be ensured, and the synchronous rectification module 403 can be safely and reliably powered.

[0128] Figure 14 For another schematic diagram of a power supply module in one embodiment, as shown in Figure 14 The third switch unit 4021 includes a seventh transistor Q7, and the fourth switch unit 4022 includes an eighth transistor Q8. The base of the seventh transistor Q7 and the base of the eighth transistor Q8 are configured to receive the driving control signal, the collector of the seventh transistor Q7 is connected to the input power supply 409, the collector of the eighth transistor Q8 is grounded, and the emitter of the seventh transistor Q7 is connected to the emitter of the eighth transistor Q8 and the first end of each first energy storage unit 4023.

[0129] Please continue to refer to Figure 14Taking the first energy storage power supply including capacitors C1 to C4 as an example, when the drive control signal TFDRV is high, the seventh transistor Q7 is turned on and the eighth transistor Q8 is turned off. Therefore, the input power supply 409 charges capacitors C1 to C4, and the voltage between VDD_C1 and CELL0 is equal to +POW. The same applies to the voltage between VDD_C2 and CELL1 (i.e., the positive electrode of the second group of cells 405), the voltage between VDD_C3 and CELL2 (i.e., the positive electrode of the third group of cells 405), and the voltage between VDD_C3 and CELL3 (i.e., the positive electrode of the fourth group of cells 405). VDD_C1 can be understood as the power supply module 402 corresponding to the first group of synchronous rectifier modules 403, VDD_C2 can be understood as the power supply module 402 corresponding to the third group of synchronous rectifier modules 403, and so on. In this way, the power supply module 402 can supply power to the corresponding synchronous rectifier module 403.

[0130] When the drive control signal TFDRV is at a low level, the seventh transistor Q7 is in a cut-off state, the eighth transistor Q8 is in a conduction state, the capacitors C1 to C4 are discharged, the voltage between VDD_C1 and CELL0 is zero, the voltage between VDD_C2 and CELL1, the voltage between VDD_C3 and CELL2, and the voltage between VDD_C3 and CELL3 are similar, and the power supply module 402 stops supplying power to the corresponding synchronous rectification module 403.

[0131] In the above embodiment, since the third switch unit 4021 includes the seventh transistor Q7, the fourth switch unit 4022 includes the eighth transistor Q8, and the base of the seventh transistor Q7 and the base of the eighth transistor Q8 are both used to receive the drive control signal, the collector of the seventh transistor Q7 is connected to the input power supply 409, the collector of the eighth transistor Q8 is grounded, and the emitter of the seventh transistor Q7 is connected to the emitter of the eighth transistor Q8 and the first end of each first energy storage unit 4023, therefore, the charge and discharge states of the first energy storage unit 4023 can be quickly and accurately switched mutually exclusively through the seventh transistor Q7 and the eighth transistor Q8, thereby ensuring the stable power supply of the synchronous rectification module 403.

[0132] Please continue to refer to Figure 14 In one embodiment, optionally, the power supply module 402 may further include at least one of a resistor 1401, a resistor 1402, a resistor 1403, a Zener diode DS1, a Zener diode DS2, a Zener diode DS3, a Zener diode DS4, a Zener diode DS5, a Zener diode DS6, a Zener diode DS7, a capacitor C5, a capacitor C6, a capacitor C7, and a capacitor C8.

[0133] Figure 15 FIG. 1 is a schematic diagram of another balancing circuit in an embodiment, Figure 16As shown, in one exemplary embodiment, the circuit further comprises a starting module 410. The starting module 410 is connected to the input power source 409 and the control module 401, respectively.

[0134] The starting voltage of some PWM controllers is high, and the maximum voltage of 4-series lithium iron phosphate batteries is generally not more than 14.4V, so the PWM controller cannot start normally. Therefore, in this embodiment, the input power source 409 needs to be converted into the starting voltage corresponding to the control module 401.

[0135] The starting module is used to receive a start-stop control signal, that is, BAL_EN. The start-stop control signal includes a starting signal. The starting signal is used to instruct the starting module 410 to convert the input power source 409 into a starting voltage, which can be a signal of any logic state or voltage state. Exemplarily, the starting signal can be a high-level signal. Alternatively, the starting signal can be a signal initiated by a user through an interactive element such as a key switch, or a signal generated by a second control element such as a microcontroller (MCU), and the present embodiment is not limited thereto.

[0136] Further alternatively, the starting module 410 includes, but is not limited to, a low dropout regulator (LDO) or a switching regulator.

[0137] In the above embodiments, the equalization circuit 400 further comprises the starting module 410. Since the starting module 410 is connected to the input power source 409 and the control module 401, respectively, and the starting module 410 can convert the input power source 409 into a starting voltage corresponding to the control module 401 in response to a starting signal, the starting voltage can be stably obtained from the input power source 409, and the failure of starting caused by the mismatch between the input voltage and the requirement of the control module 401 can be avoided, thereby ensuring the reliable starting of the equalization circuit 400.

[0138] Please continue to refer to Figure 15 In one exemplary embodiment, the starting module 410 comprises a fifth switching unit 4101 and a second energy storage unit 4102 connected to each other. The fifth switching unit 4101 is connected to the input power source 409, and the second energy storage unit 4102 is connected to the control module 401.

[0139] In this embodiment, the fifth switching unit 4101 is used to turn on a second path between the input power source 409 and the second energy storage unit 4102 in response to the starting signal. Alternatively, the fifth switching unit 4101 can be in an on state after receiving the starting signal to turn on the second path between the input power source 409 and the second energy storage unit 4102.

[0140] Further, after the second path is turned on, the input power 409 can charge the second energy storage unit 4102 through the second path. During the charging of the second energy storage unit 4102, the output voltage of the second energy storage unit 4102 also rises, so that the starting voltage can be obtained based on the output voltage of the second energy storage unit 4102.

[0141] In the above embodiment, the second path between the input power 409 and the second energy storage unit 4102 can be accurately input through the fifth switching unit 4101 in response to the starting signal, so as to output a stable starting voltage by storing energy in the second energy storage unit 4102.

[0142] Figure 16 For another embodiment of the starting module, as shown in FIG. 4B, in an exemplary embodiment, the fifth switching unit 4101 includes a ninth transistor Q9 and a tenth transistor Q10. Figure 16

[0143] The base of the ninth transistor Q9 is configured to receive the starting signal, the emitter of the ninth transistor Q9 is grounded, the collector of the ninth transistor Q9 is connected to the gate of the tenth transistor Q10, the source of the tenth transistor Q10 is connected to the input power 409, and the drain of the tenth transistor Q10 is connected to the second energy storage unit 4102.

[0144] Please continue to refer to Figure 16 For example, when the input power 409 is powered on and BAL_EN is a high-level signal, the ninth transistor Q9 is in a conductive state, so that the tenth transistor Q10 is also in a conductive state, the input power 409 charges the capacitor through the tenth transistor Q10 and the first capacitor, and since the voltage across the capacitor C9 cannot change abruptly, the voltage on the right side of the capacitor C9 will rise until the control module 401 is normally started.

[0145] In the above embodiment, the base of the ninth transistor Q9 is configured to receive the starting signal, the emitter of the ninth transistor Q9 is grounded, the collector of the ninth transistor Q9 is connected to the gate of the tenth transistor Q10, the source of the tenth transistor Q10 is connected to the input power 409, and the drain of the tenth transistor Q10 is connected to the second energy storage unit 4102. Therefore, the ninth transistor Q9 and the tenth transistor Q10 can reliably turn on the second path between the input power 409 and the second energy storage unit 4102 through the starting signal.

[0146] Please continue to refer to Figure 16 ​In an example embodiment, the optional starting module 410 further comprises a discharge unit connected to the fifth switch unit 4101 and the second energy storage unit 4102 respectively. The discharge unit can comprise at least one discharge element for discharging the energy of the second energy storage unit 4102, and the discharge element can include but is not limited to a resistor.

[0147] In the example embodiment, the fifth switch unit 4101 is further configured to, in response to a stop starting signal, disconnect the second path and discharge the energy of the second energy storage unit 4102 through the discharge unit.

[0148] The stop starting signal and the starting signal are two different logic states or voltage states. For example, the stop starting signal can be a low-level signal.

[0149] Please refer to Figure 16 For example, when BAL_EN is low, the ninth transistor Q9 and the tenth transistor Q10 are in the off state, and the voltage on the left side of the capacitor C9 can be quickly discharged through the resistor 1607 for the next start.

[0150] In the above example, the starting module 410 further comprises a discharge unit, and the discharge unit is connected to the fifth switch unit 4101 and the second energy storage unit 4102 respectively. In addition, the fifth switch unit 4101 can disconnect the second path and discharge the energy of the second energy storage unit 4102 through the discharge unit in response to the stop starting signal. Therefore, not only can the overvoltage damage caused by the long-term charging of the second energy storage unit 4102 be avoided, but also the next charging process of the second energy storage unit 4102 can be facilitated, and a relatively stable starting voltage can be provided.

[0151] In one embodiment, the starting module 410 can further include at least one of the following: (1) a filter capacitor C10; a first end of the filter capacitor C10 is connected to the second energy storage unit 4102 and the preset power supply, and a second end of the filter capacitor C10 is grounded. (2) a filter capacitor C11; a first end of the filter capacitor C11 is connected to the second energy storage unit 4102 and the preset power supply, and a second end of the filter capacitor C10 is grounded. (3) a resistor 1601; a first end of the resistor 1601 is used to receive a starting signal, and a second end of the resistor 1602 is connected to a base of a ninth transistor Q9. (4) a resistor 1602; a first end of the resistor 1602 is used to receive a starting signal, and a second end of the resistor 1602 is grounded. (5) a resistor 1603; the resistor 1603 is connected to a collector of the ninth transistor Q9 and a gate of a tenth transistor Q10, respectively. (6) a resistor 1604; the resistor 1604 is connected to a source of the tenth transistor Q10 and the gate of the tenth transistor Q10, respectively. (7) a resistor 1605; the resistor 1605 is connected to a drain of the tenth transistor Q10 and the second energy storage unit 4102, respectively. (8) a resistor 1606; the resistor 1606 is connected to the input power supply 409 and the preset power supply, respectively. (9) a voltage stabilizing tube DS9; a positive electrode of the voltage stabilizing tube DS9 is connected to the input power supply 409, and a negative electrode of the voltage stabilizing tube DS9 is connected to the preset power supply.

[0152] Further optionally, by reasonably configuring the capacitor C9, the capacitor C10 and the capacitor C11, different starting voltages can be obtained. Exemplarily, a capacitance value of the capacitor C9 is greater than a sum of a capacitance value of the capacitor C10 and a capacitance value of the capacitor C11.

[0153] In order to more clearly introduce the equalization circuit of the present application, please refer to Figure 5 , Figure 7 , Figure 8 , Figure 10 , Figure 12 , Figure 14 , Figure 16 and Figure 17 . Figure 17 For a structural schematic diagram of the equalization circuit in one embodiment, Figure 17 Exemplarily, four battery cells are taken as an example. When at least one target battery cell among the battery cell A to the battery cell D needs to be equalized, the input power supply 409 is converted into a starting voltage corresponding to the control module 401 by BAL_EN, and the target synchronous rectification module is brought into a working state by Cx_syn under the action of the channel selection module 404, that is, the corresponding secondary side winding 407 is brought into a synchronous rectification state. Further, under the condition that the target synchronous rectification module is in the working state and the secondary side winding 407 in the flyback circuit 406 is in the conduction state, the target battery cell corresponding to the secondary side winding 407 will charge the target battery cell. At the same time, the charging parameters in the charging process can be controlled by the constant current module 408.

[0154] It can be seen that the equalization circuit provided by the application does not need a complex transistor array, has a simple structure and low cost, and can be selected for any number of battery equalization, without an additional processor, so that the equalization current is controllable, and is particularly suitable for low string number lithium iron phosphate battery packs. It is particularly pointed out that when all the secondary side windings are simultaneously started in the synchronous rectification state, the entire battery pack is actually charged, and therefore the equalization circuit can also realize the function of the module equalizer in the high-voltage series battery system.

[0155] Figure 18 For a schematic diagram of a kind of energy storage device in one embodiment, as shown in Figure 18 In one embodiment, an energy storage device 1800 is also provided, which includes at least one battery cell 405 and the equalization circuit 400 of any of the above.

[0156] Those skilled in the art can understand that all or part of the processes in the above-mentioned embodiment methods can be completed by instructing the relevant hardware through a computer program. The computer program can be stored in a non-volatile computer readable storage medium, and when executed, can include the processes of the above-mentioned embodiment methods. Any reference to memory, database or other medium used in the embodiments provided in the present application can include at least one of non-volatile memory and volatile memory. The non-volatile memory can include read-only memory (ROM), magnetic tape, floppy disk, flash memory, optical storage, high-density embedded non-volatile memory, resistive random access memory (ReRAM), magnetoresistive random access memory (MRAM), ferroelectric random access memory (FRAM), phase change memory (PCM), graphene memory, etc. The volatile memory can include random access memory (RAM) or external cache memory, etc. As an illustration but not limitation, the RAM can be in various forms, such as static random access memory (SRAM) or dynamic random access memory (DRAM), etc. The database involved in the embodiments provided in the present application can include at least one of a relational database and a non-relational database. The non-relational database can include a distributed database based on a block chain, etc., without being limited thereto. The processor involved in the embodiments provided in the present application can be a general-purpose processor, a central processing unit, a graphics processing unit, a digital signal processor, a programmable logic device, a data processing logic device based on quantum computing, an artificial intelligence (AI) processor, etc., without being limited thereto.

[0157] The technical features of the above embodiments can be combined in any manner. To make the description concise, not all possible combinations of the technical features in the above embodiments are described, but as long as the combinations of the technical features do not exist contradictions, they should be considered as the scope of the present application.

[0158] The above-described embodiments are merely illustrative of several embodiments of the present application, and the description is relatively specific and detailed, but should not be understood as a limitation on the scope of the patent. It should be noted that for those skilled in the art, without departing from the concept of the present application, a number of modifications and improvements can be made, which are all within the scope of the present application. Therefore, the scope of protection of the present application should be subject to the appended claims.

Claims

1. An equalizing circuit, characterized in that: The balancing circuit includes a control module, a power supply module, at least one synchronous rectifier module, and a channel selection module corresponding to each synchronous rectifier module, each of the synchronous rectifier modules is respectively connected to a corresponding battery cell and a corresponding secondary winding in a flyback circuit, and the channel selection module is also connected to the power supply module and the corresponding synchronous rectifier module; The control module is configured to output a drive control signal to control the secondary winding in the flyback circuit to be in an off state when the drive control signal is at a first level, and to control the secondary winding in the flyback circuit to be in an on state when the drive control signal is at a second level; a channel selection module corresponding to the target synchronous rectifier module, configured to, in response to an enable signal of the target battery cell, conduct a power supply path between the power supply module and the target synchronous rectifier module, so that the power supply module supplies power to the target synchronous rectifier module through the power supply path, so as to control the target synchronous rectifier module to be in a working state; the target battery cell includes at least one of each of the battery cells, and the target synchronous rectifier module is a synchronous rectifier module corresponding to the target battery cell; The target synchronous rectification module is used to conduct the charging path between the target battery cell and the secondary winding corresponding to the target battery cell when it is in working state and the secondary winding in the flyback circuit is in the on state, so that the secondary winding corresponding to the target battery cell charges the target battery cell through the charging path.

2. The circuit according to claim 1, wherein: Each of the synchronous rectifier modules includes a rectifier control unit and a first switch unit connected to each other; the secondary winding corresponding to the synchronous rectifier module is connected to the battery cell corresponding to the synchronous rectifier module through the first switch unit, and the rectifier control unit is also connected to the corresponding channel selection module; a channel selection module corresponding to the target synchronous rectification module, configured to, in response to the enable signal, conduct a power supply path between the power supply module and the rectification control unit in the target synchronous rectification module, so as to control the rectification control unit in the target synchronous rectification module to be in an operating state; The rectifier control unit is configured to conduct the charging path through the first switch unit when the rectifier control unit is in an operating state and the secondary winding in the flyback circuit is in a conducting state.

3. The circuit according to claim 2, characterized in that The rectification control unit includes a voltage stabilizing element, and the first switch unit includes a first transistor; The main power input pin of the voltage stabilizing element is connected to the power supply module, the power input pin of the voltage stabilizing element is respectively connected to the negative pole of the corresponding secondary winding and the drain of the first transistor, the output pin of the voltage stabilizing element is connected to the negative pole of the corresponding battery cell, the gate drive pin of the voltage stabilizing element is connected to the gate of the first transistor, the source of the first transistor is connected to the negative pole of the corresponding battery cell, and the positive pole of the battery cell is connected to the positive pole of the corresponding secondary winding.

4. The circuit according to claim 2, characterized in that The rectification control unit includes a voltage stabilizing element, and the first switch unit includes a third transistor and a fourth transistor; The main power input pin of the voltage stabilizing element is connected to the power supply module, the power input pin of the voltage stabilizing element is connected to the negative electrode of the corresponding secondary winding and the drain of the third transistor, the gate of the third transistor is connected to the gate drive pin of the voltage stabilizing element, the source of the third transistor is connected to the drain of the fourth transistor and the output pin of the voltage stabilizing element, the gate of the fourth transistor is connected to the power supply module, the source of the fourth transistor is connected to the negative electrode of the corresponding battery cell, and the positive electrode of the battery cell is connected to the positive electrode of the corresponding secondary winding.

5. The circuit according to any one of claims 1 to 4, characterized in that: The circuit further includes a constant current module, which is connected to the flyback circuit and the control module respectively; The constant current module is used to obtain the primary side detection parameter of the flyback circuit, and when the primary side detection parameter is greater than the target constant current parameter, control the duty cycle of the drive control signal to a first preset value until the primary side detection parameter is less than or equal to the target constant current parameter, so that the secondary winding corresponding to the target battery cell is within a preset charging parameter range for the charging parameter of the target battery cell.

6. The circuit according to claim 5, characterized in that The constant current module includes a comparison unit and a gear adjustment unit, wherein the non-inverting input end of the comparison unit is connected to the gear adjustment unit, the inverting input end of the comparison unit is used to receive the primary side detection parameter, and the output end of the comparison unit is connected to the control module; The gear adjustment unit is configured to determine a target constant current parameter corresponding to the gear control signal in response to the gear control signal; The comparison unit is used to obtain the primary side detection parameter and, when the primary side detection parameter is greater than the target constant current parameter corresponding to the gear control signal, control the duty cycle of the drive control signal to be the first preset value until the primary side detection parameter is less than or equal to the target constant current parameter.

7. The circuit according to claim 6, characterized in that The gear adjustment unit includes a first switch sub-unit and a resistor sub-unit; the resistor sub-unit is connected to the first switch sub-unit and the non-inverting input terminal of the comparison unit respectively; The first switch subunit is used to receive the gear control signal and adjust the resistance of the resistor subunit based on the gear control signal, so as to determine the target constant current parameter corresponding to the gear control signal based on the resistance of the resistor subunit.

8. The circuit according to any one of claims 1 to 4, characterized in that: The power supply module includes a third switch unit, a fourth switch unit and at least one first energy storage unit, the third switch unit is respectively connected to the input power supply and the fourth switch unit, the first end of each first energy storage unit is respectively connected to the third switch unit and the fourth switch unit, and the second end of each first energy storage unit is connected to the corresponding synchronous rectification module; the third switching unit is configured to, in response to the drive control signal and when the drive control signal is at the first level, conduct a first path between the input power supply and each of the first energy storage units, so that the input power supply charges the first energy storage unit through the first path, and supply power to the corresponding synchronous rectification module based on the output voltage of the first energy storage unit; The fourth switching unit is configured to disconnect the first path and connect the second path between the first energy storage unit and the ground terminal in response to the drive control signal when the drive control signal is at the first level, so as to discharge the energy of each first energy storage unit and stop powering the corresponding synchronous rectification module.

9. The circuit according to any one of claims 1 to 4, characterized in that: The circuit further includes a starting module, wherein the starting module is connected to an input power supply and the control module respectively; The startup module is configured to convert the input power into a startup voltage corresponding to the control module in response to a startup signal.

10. An energy storage device, characterized in that: The energy storage device includes at least one battery cell and the balancing circuit according to any one of claims 1 to 9.

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