Balancing circuit and energy storage device

Abstract

The application relates to an equalization circuit and an energy storage device, which comprises a control module, a target synchronous rectification module and a channel selection module corresponding to the target synchronous rectification module. The control module is used for controlling a secondary winding in a flyback circuit to be in an off state when a driving control signal is a first level, and is used for controlling the secondary winding in the flyback circuit to be in an on state when the driving control signal is a second level. The channel selection module corresponding to the target synchronous rectification module is used for turning on a power supply path between a power supply module and the target synchronous rectification module in response to an enable signal of a target battery cell, so as to control the target synchronous rectification module to be in a working state. The target synchronous rectification module is used for turning on a charging path between the target battery cell and a secondary winding corresponding to the target battery cell when the target synchronous rectification module is in the working state and the secondary winding in the flyback circuit is in the on state, so as to enable the secondary winding corresponding to the target battery cell to charge the target battery cell through the charging path. The circuit can be used to flexibly realize battery cell equalization.

Description

Technical Field

[0001] This application relates to the field of new energy technology, and in particular to an equalization circuit and energy storage device. Background Technology

[0002] With the development of new energy sources, energy storage systems typically employ multiple battery cells connected in series. However, due to manufacturing variations, the capacity of each cell generally differs slightly. During use, cells with lower capacity in the battery pack age faster than others, and the capacity differences gradually increase over time. Eventually, some cells will fail due to cycle life limitations, leading to system malfunctions. Therefore, balancing multiple cells is a necessary step.

[0003] However, the current equilibrium method is not very flexible. Summary of the Invention

[0004] Therefore, it is necessary to provide a flexible balancing circuit and energy storage device to address the aforementioned technical problems.

[0005] In a first aspect, this application provides an equalization circuit, including 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 the corresponding battery cell and the 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.

[0006] The control module is used to output a drive control signal to control the secondary winding in the flyback circuit to be in the off state when the drive control signal is at the first level, and to control the secondary winding in the flyback circuit to be in the on state when the drive control signal is at the 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 and 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, thereby controlling the target synchronous rectification module to be in working state; the target battery cell includes at least one of the battery cells, 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 connect the charging path between the target cell and the corresponding secondary winding of the target cell when the secondary winding of the flyback circuit is in the working state, so that the secondary winding of the target cell can charge the target cell through the charging path.

[0009] Secondly, this application also provides an energy storage device, which includes at least one battery cell and the aforementioned equalization circuit.

[0010] The aforementioned equalization 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. Furthermore, the control module can output a drive control signal to control the secondary winding in the flyback circuit to be in a cutoff state when the drive control signal is at a first level, and to control the secondary winding in the flyback circuit to be in a conducting state when the drive control signal is at a second level. Since the target battery cell includes at least one of the various battery cells, the target synchronous rectification module is the synchronous rectification module corresponding to the target battery cell. 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 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, thereby controlling the target synchronous rectification module to be in the working state. Furthermore, when the target synchronous rectification module is in the working state and the secondary winding in the flyback circuit is in the conducting state, it is used to conduct the charging path between the target battery cell and the secondary winding corresponding to the target battery cell, so that the secondary winding 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 selected autonomously by the enable signal, and the target battery cell can be balanced by the secondary winding in the flyback circuit, which provides good flexibility. Attached Figure Description

[0011] To more clearly illustrate the technical solutions in the embodiments of this application or related technologies, the drawings used in the description of the embodiments of this application or related technologies will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0012] Figure 1 This is a schematic diagram of an equalizer in related technologies;

[0013] Figure 2 This is a schematic diagram of another type of equalizer in related technologies;

[0014] Figure 3 This is a schematic diagram of another type of equalizer in related technologies;

[0015] Figure 4 This is a schematic diagram of an equalization circuit in one embodiment;

[0016] Figure 5 This is a schematic diagram of a flyback circuit in one embodiment;

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

[0018] Figure 7 This is a schematic diagram of yet another synchronous rectification module in one embodiment;

[0019] Figure 8 This is a schematic diagram of yet another synchronous rectification module in one embodiment;

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

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

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

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

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

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

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

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

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

[0029] Figure 18 This is a schematic diagram of an energy storage device in one embodiment. Detailed Implementation

[0030] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0031] Figure 1 This is a schematic diagram of an equalizer in related technologies. Figure 1 An isolated power supply type active equalizer is shown, such as Figure 1As shown, the equalizer includes an input power supply 101, an isolation power supply 102, a transistor array 103, a processor 104, and multiple battery cells 105. This equalization method provides precise and controllable equalization current, but it requires a large number of transistors to form a transistor array for positive / negative switching and battery cell selection. If the number of battery cells is low, the processor cost becomes high. Furthermore, the processor generally needs to switch transistor arrays, which is inconvenient. In addition, only one battery cell can be equalized at a time, resulting in low efficiency.

[0032] Figure 2 This is a schematic diagram of another type of equalizer in related technologies. Figure 2 A transformerless active equalizer is shown, such as Figure 2 As shown, the equalizer includes a push-pull transformer 201, multiple push-pull transistors 202, and a battery cell 203 corresponding to each push-pull transistor 202. This method is low-cost, but the equalization current is completely uncontrollable; the current magnitude depends solely on the voltage difference between the cells. When the voltage difference between cells is small (e.g., in lithium iron phosphate battery applications), its equalization capability is weak, and it is typically only suitable for ternary lithium and lithium cobalt oxide battery applications. Furthermore, this method can only equalize all cells simultaneously and cannot select specific cells for equalization.

[0033] Figure 3 This is a schematic diagram of another type of equalizer in related technologies. Figure 3 A counter-attack active equalizer is shown, such as Figure 3 As shown, the equalizer includes an input power supply 301, a flyback converter 302, and multiple battery cells 303. This method is also relatively low-cost, but its disadvantages are... Figure 2 Similarly. Furthermore, this equalization method typically uses diode fine rectification at the output; however, the voltage drop varies depending on the diode current, resulting in extremely low equalization efficiency.

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

[0035] Figure 4 This is a schematic diagram of an equalization circuit in one embodiment, such as... Figure 4 As shown, in one 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 the corresponding battery cell 405 and the corresponding secondary winding 407 in the flyback circuit 406, and the channel selection module 404 is also connected to the power supply module 402 and the corresponding synchronous rectification module 403.

[0036] Optionally, the number of battery cells 405 is the same as the number of secondary windings 407. Each synchronous rectification module 403 corresponds one-to-one with both a battery cell 405 and a secondary winding 407, and each synchronous rectification module 403 corresponds one-to-one with a channel selection module 404. It should be noted that... Figure 4 This example uses three 405 cells. This embodiment does not limit the number of 405 cells, as long as the number of 405 cells is greater than 1.

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

[0038] Furthermore, when the drive 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 drive 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 This is a schematic diagram of a flyback circuit in one embodiment, such as... 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 connected to the corresponding battery cells 405 via corresponding synchronous rectification modules 403. It should be noted that... Figure 5 The example shown has four sets of secondary windings 407, but this embodiment is not limited to this. S1+ represents the positive terminal of the first set of secondary windings 407, S1- represents the negative terminal of the first set of secondary windings 407, S2+ represents the positive terminal of the second set of secondary windings 407, and S2- represents the negative terminal of the second set of secondary windings 407. The same logic applies to other sets of secondary windings, which will not be elaborated further here.

[0040] Optional, Figure 5 The secondary winding 407 can be made by twisting four wires together and then winding them again, so as to keep the DC resistance (DCR) and single-circuit inductance / leakage inductance as consistent as possible.

[0041] Please continue to refer to this. Figure 5Optionally, the control module 401 includes a first control element (not shown) and a control transistor 4011. The first control element is used to output a drive control signal. The first control element includes, but is not limited to, a PWM controller; exemplarily, the drive pin (DRV pin) of the PWM controller is connected to the drive control signal TFDRV. In some embodiments, to improve conversion efficiency, the first control element may typically be a quasi-resonant or active clamp controller.

[0042] The gate of the control transistor 4011 is used to receive the drive control signal TFDRV, the drain of the control transistor 4011 is connected to the primary power loop of the flyback circuit 406, and the source of the control transistor 4011 is grounded.

[0043] When the drive control signal TFDRV is at the first level, the control transistor 4011 is in the on state, and all four secondary windings 407 are in the off state; when the drive control signal TFDRV is at the second level, the control transistor 4011 is in the off state, and all four secondary windings 407 are in the on state.

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

[0045] In this embodiment, the target cell is the cell that needs to be balanced, and it includes at least one of the individual cells 405. Assume... Figure 4 The cells 405 in the middle are cell A, cell B and cell C from top to bottom. If you want to balance cells A and B, the target cells include cells A and 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] Furthermore, 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 and conduct 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, thereby controlling the target synchronous rectification module to be in working state.

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

[0049] The enable signal is used to indicate which cell 405 needs to be equalized, and it can be a signal in any logic state or voltage state. For example, the enable signal can be a high-level signal. Optionally, the enable signal can be a signal initiated by the user through an interactive element such as a push-button switch, or it can be a signal generated by a second control element such as a microcontroller unit (MCU). This embodiment is not limited to this.

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

[0051] For example, please refer to Figure 4 ,remember Figure 4 The synchronous rectification modules 403 in the middle are, from top to bottom, synchronous rectification module A, synchronous rectification module B, and synchronous rectification module C, denoted as... Figure 4 The channel selection module 404 consists of three modules from top to bottom: channel selection module A, channel selection module B, and channel selection module C. If the target battery cell includes both battery cell A and battery cell B, channel selection module A will receive an enable signal. Consequently, channel selection module A will connect the power supply path A between power supply module 402 and synchronous rectification module A. Power supply module 402 will then supply power to synchronous rectification module A through power supply path A, at which point synchronous rectification module A will be in a working state. Similarly, synchronous rectification module B connected to battery cell B will also be in a working state. However, since channel selection module A connected to battery cell C does not receive an enable signal, 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 cell and the secondary winding 407 corresponding to the target cell when it is in the working state and the secondary winding 407 in the flyback circuit 406 is in the conducting state, so that the secondary winding 407 corresponding to the target cell charges the target cell through the charging path.

[0053] Optionally, the target synchronous rectification module may include at least one switching element. Furthermore, when the secondary winding 407 in the flyback circuit 406 is in a conducting state and the target synchronous rectification module is in an operating state, the target synchronous rectification module connects the charging path between the target cell and the corresponding secondary winding 407 through its own switching element.

[0054] Continuing with the example of target cells including cell A and cell B, let's call them... Figure 4 The secondary windings 407, from top to bottom, are secondary winding A, secondary winding B, and secondary winding C. Assume secondary winding 407 is already in a conducting state. Then, since synchronous rectifier module A is in a working state, it will connect charging path A between secondary winding A and cell A, charging cell A through charging path A. Similarly, since synchronous rectifier module B is in a working state, it will connect charging path B between secondary winding B and cell B, charging cell B through charging path B. Since synchronous rectifier module B is in a non-working state, cell C will not be charged. In this way, cell A and cell B can be balanced.

[0055] The aforementioned 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. The channel selection module 404 is also connected to the power supply module 402 and the corresponding synchronous rectification module 403. Furthermore, the control module 401 can output a drive control signal to control the secondary winding 407 in the flyback circuit 406 to be in a cutoff 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 a conduction state when the drive control signal is at a second level. Since the target battery cell includes at least one of the 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 to conduct 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, thereby controlling the target synchronous rectification module to be in the working state. Furthermore, when the target synchronous rectification module is in the working state and the secondary winding 407 in the flyback circuit 406 is in the conducting state, it conducts the charging path between the target battery cell and the secondary winding 407 corresponding to the target battery cell, 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 selected autonomously by the enable signal, and the target battery cell can be balanced by the secondary winding 407 in the flyback circuit 406, which provides good flexibility.

[0056] Figure 6 This is a schematic diagram of a synchronous rectification module in one embodiment, such as... Figure 6 As shown, in an exemplary embodiment, optionally, each synchronous rectification module 403 includes a rectification control unit 4031 and a first switching unit 4032 connected to each other. Furthermore, for each synchronous rectification module 403, the secondary winding 407 corresponding to the synchronous rectification module 403 and the corresponding battery cell 405 are connected through the first switching unit 4032, and the rectification 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 connect the power supply path between the power supply module 402 and the rectification control unit 4031 in the target synchronous rectification module in response to the enable signal, so as to control the rectification control unit 4031 in the target synchronous rectification module to be in working state.

[0058] Optionally, after receiving the enable signal, the channel selection module 404 corresponding to the target synchronous rectification module can control its own switching element to be in the conducting state, so as to conduct 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 the working state.

[0059] Furthermore, the rectifier control unit 4031, when in operation and with the secondary winding 407 in the flyback circuit 406 in a conducting state, connects the charging path via the first switching unit 4032. Optionally, when the secondary winding 407 is in a conducting state and the rectifier control unit 4031 is in operation, the rectifier control unit 4031 can control the first switching unit 4032 to be in a conducting state. When the first switching unit 4032 is in a conducting state, the charging path between the corresponding secondary winding 407 and the battery cell 405 will be connected.

[0060] In the above embodiments, the first switching unit 4032 is triggered to open the charging path only when the target cell is selected and the secondary winding 407 is in the on state, which improves the accuracy of equalization. Furthermore, opening the charging path by the first switching unit 4032 can also improve the efficiency of equalization.

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

[0062] Figure 7 The diagram illustrates the synchronous rectification module 403 connected to the first secondary winding 407 and the first cell 405. It can be understood that the other synchronous rectification modules 403 are similar.

[0063] like Figure 7 As shown, the main power input pin of the voltage regulator U1 (i.e. Figure 7 The VDD pin is connected to the power supply module 402, and the power input pin of the voltage regulator U1 is also connected to the power input pin. Figure 7 The VD pins are connected to the negative terminals of the corresponding secondary windings 407 (e.g., the negative terminal S1- of the first secondary winding 407) and the drain of the first transistor Q1, respectively. The output pin of the voltage regulator U1 (i.e., Figure 7The VS pin is connected to the negative terminal of the corresponding cell 405 (e.g., connected to the negative terminal CELL0 of the first group of cells 405). The gate drive pin of the voltage regulator U1 (i.e., the VG pin in the figure) is connected to the gate of the first transistor Q1. The source of the first transistor Q1 is connected to the negative terminal of the corresponding cell 405. The positive terminal of the cell 405 (e.g., the positive terminal CELL1 of the first group of cells 405) is connected to the positive terminal of the corresponding secondary winding 407 (e.g., the positive terminal S1+ of the first group of secondary windings 407).

[0064] Please continue to refer to this. Figure 7 When the target synchronous rectification module is in operation and the secondary winding 407 is in the conducting state, the output pin of the voltage regulator U1 in the target synchronous rectification module will drive the first transistor Q1 to be in the conducting state. The voltage across the secondary winding 407 is close to the voltage across the cell 405, so that the corresponding cell 405 is charged through the output voltage of the secondary winding 407.

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

[0066] Please continue to refer to this. Figure 7 In one exemplary embodiment, optionally, 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 terminal of the corresponding secondary winding 407, and the source of the second transistor Q2 is connected to the negative terminal of the corresponding battery cell 405.

[0067] Please continue to refer to this. Figure 7 When the target synchronous rectification module is in operation and the secondary winding 407 is in a conducting state, the output pin of the voltage regulator U1 in the target synchronous rectification module will drive the first transistor Q1 and the second transistor Q2 to be in a conducting state, so as to charge the corresponding cell 405 through the output voltage of the secondary winding 407. Furthermore, when the secondary winding 407 is in a cutoff state, or when the synchronous rectification module 403 is not in operation, the second transistor Q2 can also prevent the cell 405 from discharging into the secondary winding 407, ensuring that the cell 405 does not leak current.

[0068] In the above embodiment, since the first switching unit 4032 also includes a second transistor Q2, and 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 terminal of the corresponding secondary winding 407, and the source of the second transistor Q2 is connected to the negative terminal of the corresponding cell 405, the second transistor Q2 can also prevent the cell 405 from discharging to the secondary winding 407, thereby improving the reliability of the equalization circuit 400.

[0069] Please continue to refer to this. Figure 7 In one embodiment, optionally, each synchronous rectification module 403 may further include at least one of the following: (1) a drive resistor 701; the drive resistor 701 is connected to the gate drive pin of the voltage regulator U1 and the gate of the second transistor Q2, respectively. (2) a pull-down resistor 702; the pull-down resistor 702 is connected to the gate drive pin of the voltage regulator U1 and the source of the second transistor Q2, respectively. (3) a capacitor 703; the capacitor 703 is connected to the feedback pin of the voltage regulator U1 (i.e., the feedback pin of the voltage regulator U1). Figure 7 (4) Capacitor 704; Capacitor 704 is connected to the positive terminal and the negative terminal of battery cell 405 respectively. (5) Capacitor 705; Capacitor 705 is connected to the positive terminal and the negative terminal of battery cell 405 respectively. (6) Fuse 706; Fuse 706 is connected to the positive terminal of secondary winding 407 and the positive terminal of battery cell 405 respectively. (7) Capacitor 707; Capacitor 707 is connected to the positive terminal of secondary winding 407 and the source of first transistor Q1 respectively. (8) Power dissipation resistor 708; Power dissipation resistor 708 is connected to the positive terminal of secondary winding 407 and the source of first transistor Q1 respectively.

[0070] Please continue to refer to this. Figure 7 In one embodiment, when the secondary winding 407 is in the on state, if the voltage regulator U1 is powered, the target synchronous rectification module works normally. Pin 1 (i.e., VG pin) of the voltage regulator U1 can drive the first transistor Q1 and the second transistor Q2 to be in the on state through the drive resistor 701. The voltage across the secondary winding (hereinafter referred to as winding voltage) is close to the voltage across the corresponding cell (hereinafter referred to as cell voltage), and the winding voltage charges the corresponding cell.

[0071] If the voltage regulator U1 is not powered, the first transistor Q1 and the second transistor Q2 are in the off state. Therefore, current must flow through the body diodes of the first transistor Q1 and the second transistor Q2. The winding voltage is higher than the corresponding cell voltage. Let the forward voltage drop of the body diode be Vd, then the winding voltage is equal to the sum of the corresponding cell voltage and twice Vd.

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

[0073] Assuming the voltages across multiple battery cells are identical, when any secondary winding is in synchronous rectification, its voltage equals the corresponding battery cell voltage. According to transformer characteristics, the output voltage of the secondary winding in asynchronous rectification will also be synchronously clamped to the battery cell voltage. Due to the forward voltage of the body diode, theoretically, this secondary winding will be unable to output current to the corresponding battery cell. In reality, transformers always have leakage inductance. Without proper handling, leakage inductance energy will be transferred to the battery cells. Therefore, by appropriately setting the resistance of the energy-dissipating resistor 708 and the capacitance of the capacitor 707, leakage inductance energy can be absorbed, ensuring no energy is transferred to the battery cells. For example, the product of the capacitance of capacitor 707 and the voltage difference across the leakage inductance can be equal to the square of the leakage inductance divided by the resistance of the energy-dissipating resistor 708.

[0074] Thus, through the above design, it is possible to achieve output only from the secondary winding in synchronous rectification state, while the secondary winding in asynchronous rectification state does not output, thereby achieving charging balance for a specific battery cell.

[0075] Figure 8 This is a schematic diagram of another synchronous rectification module in one embodiment, such as... Figure 8 As shown, in an exemplary embodiment, optionally, the rectifier control unit 4031 includes a voltage regulator U1, and the first switching unit 4032 includes a third transistor Q3 and a fourth transistor Q4.

[0076] Similarly, Figure 8 The diagram illustrates the synchronous rectification module 403 connected to the first secondary winding 407 and the first battery cell 405; other synchronous rectification modules 403 are illustrated similarly. Figure 8 As shown, the main power input pin of the voltage regulator U1 is connected to the power supply module 402. The power input pin of the voltage regulator U1 is connected to the negative terminal 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 regulator 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 regulator 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 terminal of the corresponding battery cell 405. The positive terminal of the battery cell 405 is connected to the positive terminal of the corresponding secondary winding 407.

[0077] Please continue to refer to this. Figure 8When the target synchronous rectification module is in operation and the secondary winding 407 is in the conducting state, the output pin of the voltage regulator 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 presence of the power supply module 402, so as to charge the corresponding cell 405 through the output voltage of the secondary winding 407. Figure 8 The principle and Figure 7 Similarly, this will not be elaborated upon here.

[0078] In the above embodiment, since the main power input pin of the voltage regulator U1 is connected to the power supply module 402, the power input pin of the voltage regulator U1 is connected to the negative terminal 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 regulator 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 regulator 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 terminal of the corresponding battery cell 405, and the positive terminal of the battery cell 405 is connected to the positive terminal of the corresponding secondary winding 407, the charging path can be efficiently turned on when equalization is required through the voltage regulator U1, the third transistor Q3 and the fourth transistor Q4.

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

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

[0081] The constant current module 408 is used to acquire the primary-side detection parameters of the flyback circuit 406, denoted as CS. Please refer to [reference needed]. Figure 5Optionally, the primary-side detection parameters of the flyback circuit 406 can be obtained through resistor 4014. These primary-side detection parameters include, but are not limited to, detection current or detection voltage. For example, 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] Furthermore, the constant current module 408 compares the primary edge detection parameters with the target constant current parameters. The target constant current parameters are constant current parameters that are referenced by the primary edge detection parameters, and can be preset constant current parameters.

[0083] Furthermore, when 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 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 parameters of the secondary winding 407 corresponding to the target battery cell are within the preset charging parameter range. The first preset value is used to reduce the duty cycle of the drive control signal, and it can be a number close to 0, such as 0. The charging parameters include, but are not limited to, the charging current (also called the balancing current) used by the secondary winding 407 corresponding to the target battery cell to charge the target battery cell. The preset charging parameter range can be set according to actual needs, and this embodiment does not impose any limitations.

[0084] For example, taking the primary-side detection parameters including the primary-side detection current as an example, when the control transistor 4011 is in the on state, the constant current module 408 obtains the primary-side detection current of the flyback circuit 406 and compares it with the target constant current parameter set by the primary-side detection current. 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; 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 near the target constant current parameter. During this process, since the primary-side detection current is maintained near the target constant current parameter, the charging parameters of the secondary winding 407 corresponding to the target cell will also be within the preset charging parameter range.

[0085] In the above embodiments, since the constant current module 408 can obtain the primary side detection parameters of the flyback circuit 406, and when the primary side detection parameters are greater than the target constant current parameters, it controls the duty cycle of the drive control signal to a first preset value until the primary side detection parameters are less than or equal to the target constant current parameters. In this way, the secondary winding 407 corresponding to the target cell can be made to charge the target cell within the preset charging parameter range, achieving a similar effect to constant current balancing. Moreover, the balancing process is controllable and has high reliability.

[0086] Please continue to refer to this. Figure 9In one exemplary embodiment, optionally, the constant current module 408 includes 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, the inverting input of the comparison unit 4081 is used to receive primary-side detection parameters, and the output of the comparison unit 4081 is connected to the control module 401.

[0087] In this embodiment, the gear adjustment unit 4082 is used to determine the 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 used to set the target constant current parameter. It is understood that the gear control signal can be a signal initiated by the user through interactive elements such as push-button switches, or a signal generated by a second control element such as a microcontroller; this embodiment is not limited to these possibilities.

[0088] Optionally, the gear control signal can indicate the level of the target constant current parameter, with different levels corresponding to different target constant current parameters. For example, a high-level signal from the gear adjustment unit 4082 corresponds to a larger target constant current parameter, while a low-level signal from the gear adjustment unit 4082 corresponds to a smaller target constant current parameter. Further optionally, the gear adjustment unit 4082 can switch between different target constant current parameters via a relay.

[0089] Furthermore, the comparison unit 4081 is used to acquire 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, it controls 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.

[0090] In the above embodiments, the corresponding target constant current parameters can be flexibly set through the gear adjustment unit 4082, which not only makes the balancing process controllable, but also adapts to different cell states and charging needs, thus expanding the application scenarios.

[0091] Please continue to refer to this. Figure 9 In one exemplary embodiment, optionally, the gear adjustment unit 4082 includes a first switch subunit 4082a and a resistor subunit 4082b. The resistor subunit 4082b is connected to both the first switch subunit 4082a and the non-inverting input terminal of the comparator unit 4081.

[0092] In this embodiment, the first switch subunit 4082a is used to receive a gear control signal and adjust the resistance value of the resistor 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 resistor subunit 4082b.

[0093] Optionally, the first switching subunit 4082a can be a relay. Under different gear control signals, the relay selects different resistance values ​​of the resistor subunit 4082b and generates the target constant current parameter corresponding to the gear control signal based on the different resistance values ​​of the resistor subunit 4082b. The resistor subunit 4082b can be implemented using a sliding rheostat, a series adjustable resistor, a manually adjustable resistor, etc., and this embodiment does not impose any limitations.

[0094] In the above embodiment, since the gear control signal is received by the first switch subunit 4082a and the resistance value of the resistor subunit 4082b is adjusted based on the gear control signal, the target constant current parameter corresponding to the gear control signal can be determined efficiently based on the resistance value of the resistor subunit 4082b without increasing the cost too much.

[0095] Figure 10 This is a schematic diagram of another constant current module in one embodiment, such as... Figure 10 As shown, in an exemplary embodiment, optionally, the first switching subunit 4082a includes a fifth transistor Q5, and the resistor subunit 4082b includes a first resistor 1001 and a second resistor 1002.

[0096] In this configuration, the gate of the fifth transistor Q5 is used 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 terminal of the first resistor 1001. The second terminal of the first resistor 1001 is connected to the first terminal of the second resistor 1002. The second terminal of the second resistor 1002 is connected to both the non-inverting input terminal of the comparator unit 4081 and the second terminal of the first resistor 1001. The first terminal of the second resistor 1002 is also connected to a preset power supply (i.e.,...). Figure 10 (VCC in the original text). FB can represent the feedback pin of the PWM controller.

[0097] When the gear control signal is high, the fifth transistor Q5 is in the conducting state, the first resistor 1001 and the second resistor 1002 are connected in parallel, the voltage at the non-inverting input of the comparator unit 4081 decreases, and the target constant current parameter decreases. Similarly, when the gear control signal is low, the fifth transistor Q5 is in the cutoff state, which also corresponds to a target constant current parameter.

[0098] It should be noted that, Figure 10 This example only illustrates one alternative configuration. By adding multiple transistors similar to the fifth transistor Q5 and the second resistor 1002, multiple target constant current parameters can be obtained.

[0099] In the above embodiment, since the gate of the fifth transistor Q5 is used 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 terminal of the first resistor 1001, the second terminal of the first resistor 1001 is connected to the first terminal of the second resistor 1002, the second terminal of the second resistor 1002 is connected to the non-inverting input terminal of the comparator unit 4081 and the second terminal of the first resistor 1001 respectively, and the first terminal of the second resistor 1002 is also connected to a preset power supply, 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, thereby obtaining different target constant current parameters.

[0100] Please continue to refer to this. Figure 10 In one embodiment, optionally, the constant current module 408 may further include at least one of the following: (1) a resistor 1003; one end of the resistor 1003 is used 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 used to receive the primary-side detection parameters, and the other end of the resistor 1007 is connected to the inverting input terminal of the comparison unit 4081. (6) Resistor 1008; One end of resistor 1008 is used to receive the primary-side detection parameters, and the other end of resistor 1008 is connected to the inverting input terminal of comparator unit 4081. (7) Capacitor 1009; One end of capacitor 1009 is used to receive the primary-side detection parameters, and the other end of capacitor 1009 is connected to the inverting input terminal of comparator unit 4081. (8) Resistor 1010; Resistor 1010 is connected to the inverting input terminal and the output terminal of comparator unit 4081 respectively. (9) Capacitor 1011; Capacitor 1011 is connected to the inverting input terminal and the output terminal of comparator unit 4081 respectively. (10) Capacitor 1012; Capacitor 1012 is connected to the inverting input terminal and the output terminal of comparator unit 4081 respectively. (11) Diode 1013; The cathode of diode 1013 is connected to the output terminal of comparator unit 4081, and the anode of diode 1013 is connected to the output terminal of constant current module 408. (12) Resistor 1014; Resistor 1014 is connected to the positive terminal of diode 1013.

[0101] Please continue to refer to this. Figure 10Resistors 1007 and 1008, capacitors 1009 and 1010, capacitors 1012 and 1011 together form a feedback compensation network. The output of the comparator unit 4081 is connected to the feedback pin of the PWM controller through diode 1013 and resistor 1014. If the primary-side detected parameter is greater than the target constant current parameter, the comparator unit 4081 outputs a low level, the FB pin of the PWM controller is pulled low through diode 1013 and resistor 1014, and the drive pin of the PWM controller stops oscillating. This continues until the primary-side detected parameter is less than or equal to the target constant current parameter. At this point, the comparator unit 4081 outputs a high level, diode 1013 is reverse-biased and cut off, the FB pin of the PWM controller is normal, and the drive pin of the PWM controller oscillates normally.

[0102] In some embodiments, Figure 10 Based on this, the constant current module 408 may also include a feedback compensation network. By adjusting the parameters of the feedback compensation network, the equalization circuit can operate more stably in the input constant current state.

[0103] Figure 11 This is a schematic diagram of a channel selection module in one embodiment, such as... Figure 11 As shown, in an exemplary embodiment, optionally, each channel selection module 404 includes a second switching unit 4042 and an optocoupler unit 4041. The optocoupler unit 4041 is connected to both the second switching unit 4042 and the power supply module 402.

[0104] In this embodiment, the second switching unit 4042 is used to receive the channel control signal of the x-th cell 405, denoted as Cx_syn. For example, when C1_syn is high, it indicates that the first cell A needs to be equalized, when C2_syn is high, it indicates that the second cell B needs to be equalized, and so on.

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

[0106] Furthermore, the optocoupler unit 4041 is used to conduct the corresponding power supply path when it is in the conducting state. Continuing the example above, after receiving the enable signal from cell A, the second switch unit 4042 in channel selection module A will conduct its own optocoupler unit 4041 to conduct the power supply path A between power supply module 402 and synchronous rectification module A through its own optocoupler unit 4041.

[0107] In the above embodiments, since the optocoupler unit 4041 can be controlled to conduct the corresponding power supply path through the enable signal and the second switch unit 4042, the optocoupler isolation can not only improve the safety of control, but also accurately control the path, thereby enhancing the reliability and stability of the channel selection module 404.

[0108] Figure 12 This is a schematic diagram of yet another channel selection module in one embodiment, such as... Figure 12 As shown, in one exemplary embodiment, optionally, the second switching unit 4042 includes a sixth transistor Q6, and the optocoupler unit 4041 integrates a diode subunit (such as...). Figure 12 (as shown in pins 1 and 2 of the optocoupler unit 4041) and transistor unit (as shown in pins 1 and 2) Figure 12 Pins 3 and 4 of the optocoupler unit 4041 are shown.

[0109] The base of the sixth transistor Q6 is used 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 terminal of the diode sub-unit, the positive terminal of the diode sub-unit is connected to the input power supply 409, and the transistor sub-unit is connected to the power supply module 402. That is, when the sixth transistor Q6 is in the conducting state, it controls the diode sub-unit in the optocoupler unit 4041 to be in the conducting state, thereby controlling the transistor sub-unit in the optocoupler unit 4041 to be in the conducting state, so that the entire optocoupler unit 4041 is in the conducting state. The input power supply 409 may include, but is not limited to, the total battery voltage or an external DC power supply.

[0110] Understandable, Figure 12 The diagram shows the channel selection module 404 corresponding to the synchronous rectification module 403 of the first battery cell 405; the other channel selection modules 404 are similar. Please refer to the following documentation. Figure 12 VDD and VDD_C1 represent the power supply of the voltage regulator U1 in the synchronous rectification module A, for example, connected to the voltage regulator U1 in the synchronous rectification module A, and POW+ represents the input power supply.

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

[0112] In the above embodiment, since the base of the sixth transistor Q6 is used 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 terminal of the diode sub-unit, the positive terminal of the diode sub-unit is connected to the input power supply 409, and the transistor sub-unit is connected to the power supply module 402, the sixth transistor Q6 can quickly respond to the enable signal, and achieve electrical isolation in conjunction with the optocoupler unit 4041, which has 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 this. Figure 12 In one embodiment, the channel selection module 404 may further include at least one of resistors 1201, 1202 and 1203.

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

[0115] In this embodiment, the aforementioned channel control signal further includes a stop enable signal. The stop enable signal is used to stop equalizing the battery cell 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 the user through an interactive element such as a push-button switch, or a signal generated by a second control element such as a microcontroller unit (MCU); this embodiment is not limited to these possibilities.

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

[0117] Optionally, 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 through the switching element in the channel selection module 404 when it receives the stop enable signal of the target battery cell.

[0118] Optionally, the second switching unit 4042 is configured to receive a stop enable signal and control the optocoupler unit 4041 to be in a cut-off state based on the enable signal. Furthermore, the optocoupler unit 4041 is configured to disconnect the corresponding power supply path when in the cut-off state.

[0119] Please continue to refer to this. Figure 12 When C1-syn is a low-level signal, that is, when the base of the sixth transistor Q6 receives the stop enable signal of cell A, the sixth transistor Q6 is in the off state, the optocoupler unit 4041U1 is also turned off, 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 equalization process can be stopped in a timely manner by disabling the enable signal, thereby improving the reliability of the equalization process.

[0121] Synchronous rectification modules typically require an operating voltage of 5V or higher, while the output voltage of each battery cell does not exceed 4.2V (the maximum voltage of a ternary lithium battery). Therefore, an additional power supply is needed to power the synchronous rectification module. Related technologies usually involve adding an extra power supply winding to the transformer, but if this method is used in this application, multiple power supply windings would be required, resulting in higher costs. Therefore, this application provides an alternative, lower-cost power supply module.

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

[0123] The third switching unit 4021 is connected to the input power supply 409 and the fourth switching unit 4022, respectively. The first end of each first energy storage unit 4023 is connected to the third switching unit 4021 and the fourth switching 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 battery cells 405.

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

[0125] The fourth switching unit 4022 is used to respond to the drive control signal. When the drive control signal is at the first level, it disconnects the first path and connects the second path between the first energy storage unit 4023 and the ground terminal to release the energy of each first energy storage unit 4023 and stop supplying power to the corresponding synchronous rectification module 403.

[0126] For example, when the drive 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 of the first energy storage units 4023 is opened by the third switch unit 4021, and the first energy storage units 4023 are in the charging state. When the drive 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 opened by the fourth switch unit 4022, and the first energy storage unit 4023 is in the discharging state.

[0127] In the above embodiments, since the third switching unit 4021 can respond to the drive control signal, when the drive control signal is at the first level, it can conduct the first path between the input power supply 409 and each of the first energy storage units 4023, so that the input power supply 409 can charge the first energy storage unit 4023 through the first path, and supply power to the corresponding synchronous rectification module 403 based on the output voltage of the first energy storage unit 4023. Furthermore, the fourth switching unit 4022 can respond to the drive control signal, when the drive control signal is at the first level, it can disconnect the first path and conduct the second path between the first energy storage unit 4023 and the ground terminal, so as to release the energy of each of the first energy storage units 4023 and stop supplying power to the corresponding synchronous rectification module 403. Therefore, the third switching unit 4021 and the fourth switching unit 4022 can be controlled efficiently and accurately through the drive control signal, so as to realize the rapid switching of the charging and discharging state of the first energy storage unit 4023, ensure the stable power supply of the synchronous rectification module 403, and safely and reliably supply power to the synchronous rectification module 403.

[0128] Figure 14 This is a schematic diagram of another power supply module in one embodiment, such as... Figure 14 As shown, the third switching unit 4021 includes a seventh transistor Q7, and the fourth switching unit 4022 includes an eighth transistor Q8. The bases of both the seventh transistor Q7 and the eighth transistor Q8 are used to receive drive control signals. 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 terminal of each of the first energy storage units 4023.

[0129] Please continue to refer to this. 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 in the on state and the eighth transistor Q8 is in the off state. Therefore, the input power supply 409 will charge capacitors C1 to C4. The voltage between VDD_C1 and CELL0 is equal to +POW. Similarly, the voltages between VDD_C2 and CELL1 (i.e., the positive terminal of the second group of cells 405), VDD_C3 and CELL2 (i.e., the positive terminal of the third group of cells 405), and VDD_C3 and CELL3 (i.e., the positive terminal of the fourth group of cells 405) are calculated. VDD_C1 can be understood as the power supply module 402 corresponding to the first group of synchronous rectification modules 403, VDD_C2 can be understood as the power supply module 402 corresponding to the third group of synchronous rectification modules 403, and so on. In this way, the power supply module 402 can supply power to the corresponding synchronous rectification module 403.

[0130] When the drive control signal TFDRV is low, the seventh transistor Q7 is in the off state, the eighth transistor Q8 is in the on state, capacitors C1 to C4 discharge, the voltage between VDD_C1 and CELL0 is zero, and the voltage between VDD_C2 and CELL1, VDD_C3 and CELL2, and VDD_C3 and CELL3 are similarly zero. The power supply module 402 stops supplying power to the corresponding synchronous rectification module 403.

[0131] In the above embodiments, since the third switching unit 4021 includes a seventh transistor Q7 and the fourth switching unit 4022 includes an eighth transistor Q8, and the bases of both the seventh transistor Q7 and the eighth transistor Q8 are used to receive drive control signals, 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 terminal of each first energy storage unit 4023, the charging and discharging states of the first energy storage unit 4023 can be switched quickly and accurately through the seventh transistor Q7 and the eighth transistor Q8, ensuring a stable power supply to the synchronous rectification module 403.

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

[0133] Figure 15 This is a schematic diagram of another equalization circuit in one embodiment, such as... Figure 16As shown, in one exemplary embodiment, the circuit optionally includes a startup module 410. The startup module 410 is connected to both the input power supply 409 and the control module 401.

[0134] Some PWM controllers have high startup voltages; the maximum voltage of a four-cell lithium iron phosphate battery is generally no more than 14.4V, preventing the PWM controller from starting normally. Therefore, in this embodiment, the input power supply 409 needs to be converted to the startup voltage corresponding to the control module 401.

[0135] The startup module receives the start / stop control signal, namely BAL_EN. The start / stop control signal includes a startup signal. The startup signal instructs the startup module 410 to convert the input power supply 409 into a startup voltage; it can be a signal in any logic state or voltage state. For example, the startup signal can be a high-level signal. Alternatively, the startup signal can be a signal initiated by the user through an interactive element such as a push-button switch, or a signal generated by a second control element such as a microcontroller unit (MCU); this embodiment is not limited to these limitations.

[0136] Further optionally, the startup module 410 may include, but is not limited to, a low dropout regulator (LDO) or a switching regulator.

[0137] In the above embodiments, the equalization circuit 400 further includes a startup module 410. Since the startup module 410 is connected to the input power supply 409 and the control module 401 respectively, and the startup module 410 can respond to the startup signal to convert the input power supply 409 into the startup voltage corresponding to the control module 401, the matching startup voltage can be stably obtained from the input power supply 409, avoiding startup failure caused by the mismatch between the input voltage and the requirements of the control module 401, and ensuring the reliable startup of the equalization circuit 400.

[0138] Please continue to refer to this. Figure 15 In one exemplary embodiment, optionally, the startup module 410 includes 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 supply 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 connect the second path between the input power supply 409 and the second energy storage unit 4102 in response to a start signal. Optionally, the fifth switching unit 4101 can be in a conducting state after receiving the start signal to connect the second path between the input power supply 409 and the second energy storage unit 4102.

[0140] Furthermore, once the second path is activated, the input power supply 409 can charge the second energy storage unit 4102 through the second path. During the charging process of the second energy storage unit 4102, the output voltage of the second energy storage unit 4102 will also increase, thus the start-up voltage can be obtained based on the output voltage of the second energy storage unit 4102.

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

[0142] Figure 16 This is a schematic diagram of another startup module in one embodiment, such as... Figure 16 As shown, in an exemplary embodiment, optionally, the fifth switching unit 4101 includes a ninth transistor Q9 and a tenth transistor Q10.

[0143] In this configuration, the base of the ninth transistor Q9 is used to receive the start 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 supply 409, and the drain of the tenth transistor Q10 is connected to the second energy storage unit 4102.

[0144] Please continue to refer to this. Figure 16 Taking the second energy storage unit 4102 including capacitor C9 as an example, when the input power supply 409 is powered on and the BAL_EN signal is high, the ninth transistor Q9 is in the conducting state, so that the tenth transistor Q10 is also in the conducting state. The input power supply 409 charges the capacitor through the tenth transistor Q10 and the first capacitor. Since the voltage across the capacitor C9 cannot change abruptly, the voltage on the right side of the capacitor C9 will increase until the control module 401 starts normally.

[0145] In the above embodiment, since the base of the ninth transistor Q9 is used to receive the start 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 supply 409, and the drain of the tenth transistor Q10 is connected to the second energy storage unit 4102, the second path between the input power supply 409 and the second energy storage unit 4102 can be reliably turned on by the start signal through the ninth transistor Q9 and the tenth transistor Q10.

[0146] Please continue to refer to this. Figure 16In one exemplary embodiment, optionally, the startup module 410 further includes a discharge unit, which is connected to the fifth switching unit 4101 and the second energy storage unit 4102. The discharge unit may include at least one discharge element for discharging energy from the second energy storage unit 4102, and the discharge element may include, but is not limited to, a resistor.

[0147] In this embodiment, the fifth switching unit 4101 is also used to disconnect the second path in response to the stop start signal and release the energy of the second energy storage unit 4102 through the discharge unit.

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

[0149] Please refer to Figure 16 Taking the discharge unit 4103 including resistor 1607 as an example, when BAL_EN is low, the ninth transistor Q9 and the tenth transistor Q10 are in the off state. The voltage on the left side of capacitor C9 can be quickly discharged through resistor 1607 so that it can be used for the next startup.

[0150] In the above embodiment, the startup module 410 further includes a discharge unit. Since the discharge unit is connected to the fifth switch unit 4101 and the second energy storage unit 4102 respectively, and the fifth switch unit 4101 can respond to the stop startup signal, disconnect the second path, and discharge the energy of the second energy storage unit 4102 through the discharge unit, it can not only avoid overvoltage damage caused by the second energy storage unit 4102 being energized for a long time, but also facilitate the next charging process of the second energy storage unit 4102 by providing a more stable startup voltage.

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

[0152] Alternatively, by appropriately configuring capacitors C9, C10, and C11, different starting voltages can be obtained. For example, the capacitance value of capacitor C9 is greater than or equal to the sum of the capacitance values ​​of capacitors C10 and C11.

[0153] To more clearly illustrate the equalization circuit of this application, please refer to... Figure 5 , Figure 7 , Figure 8 , Figure 10 , Figure 12 , Figure 14 , Figure 16 and Figure 17 . Figure 17 This is a schematic diagram of the equalization circuit in one embodiment. Figure 17 Taking four battery cells as an example, when balancing at least one target cell from cells A to D is required, the input power supply 409 is converted into the start-up voltage corresponding to the control module 401 via BAL_EN, and the target synchronous rectification module is put into operation via Cx_syn under the action of the channel selection module 404, which means that the corresponding secondary winding 407 enters the synchronous rectification state. Then, with the target synchronous rectification module in operation and the secondary winding 407 in the flyback circuit 406 in a conducting state, the secondary winding 407 corresponding to the target cell will charge the target cell. Simultaneously, the charging parameters during the charging process can be controlled by the constant current module 408.

[0154] As can be seen, the equalization circuit provided in this application does not require a complex transistor array, has a simple structure, and low cost. Furthermore, it can be used to equalize any number of cells without requiring an additional processor, and the equalization current is controllable, making it particularly suitable for low-series-number lithium iron phosphate battery packs. It should be noted that when all secondary windings are simultaneously activated in synchronous rectification mode, the entire battery pack is actually being charged; therefore, this equalization circuit can also function as a module equalizer in a high-voltage series battery system.

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

[0156] Those skilled in the art will understand that all or part of the processes in the methods of the above embodiments can be implemented by a computer program instructing related hardware. The computer program can be stored in a non-volatile computer-readable storage medium, and when executed, it can include the processes of the embodiments of the above methods. Any references to memory, databases, or other media used in the embodiments provided in this application can include at least one of non-volatile memory and volatile memory. Non-volatile memory can include read-only memory (ROM), magnetic tape, floppy disk, flash memory, optical memory, high-density embedded non-volatile memory, resistive random access memory (ReRAM), magnetic random access memory (MRAM), ferroelectric random access memory (FRAM), phase change memory (PCM), graphene memory, etc. Volatile memory can include random access memory (RAM) or external cache memory, etc. By way of illustration and not limitation, RAM can take many forms, such as Static Random Access Memory (SRAM) or Dynamic Random Access Memory (DRAM). The databases involved in the embodiments provided in this application may include at least one type of relational database and non-relational database. Non-relational databases may include, but are not limited to, blockchain-based distributed databases. The processors involved in the embodiments provided in this application may be general-purpose processors, central processing units, graphics processing units, digital signal processors, programmable logic devices, quantum computing-based data processing logic devices, artificial intelligence (AI) processors, etc., and are not limited to these.

[0157] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this application.

[0158] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of this patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this application should be determined by the appended claims.

Claims

1. An equalization circuit, characterized by, The equalization circuit comprises a control module, a power supply module, at least one synchronous rectification module, and a channel selection module corresponding to each of the synchronous rectification modules, each of the synchronous rectification modules is connected to a corresponding battery cell and a corresponding secondary winding in the flyback circuit, and the channel selection module is further connected to the power supply module and the corresponding synchronous rectification module; The control module is configured to output a drive control signal, 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 control the secondary winding in the flyback circuit to be in an on state when the drive control signal is at a second level; The channel selection module corresponding to the target synchronous rectification module is configured to, in response to an enable signal of a target battery cell, turn on a power supply path between the power supply module and the target synchronous rectification module, and enable the power supply module to supply 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 comprises at least one of the battery cells, and the target synchronous rectification module is a synchronous rectification module corresponding to the target battery cell; The target synchronous rectification module is configured to, when in the working state and the secondary winding in the flyback circuit is in the on state, turn on a charging path between the target battery cell and the secondary winding corresponding to the target battery cell, so as to enable the secondary winding corresponding to the target battery cell to charge the target battery cell through the charging path; Each of the synchronous rectification modules comprises a rectification control unit and a first switch unit connected to each other; the secondary winding corresponding to the synchronous rectification module is connected to the battery cell corresponding to the synchronous rectification module through the first switch unit, and the rectification control unit is further connected to the corresponding channel selection module; The rectification control unit comprises a voltage stabilizing element; the first switch unit comprises a first transistor, or the first switch unit comprises a third transistor and a fourth transistor; In the case where the first switch unit comprises the first transistor, a main power input pin of the voltage stabilizing element is connected to the power supply module, power input pins of the voltage stabilizing element are respectively connected to a negative electrode of the corresponding secondary winding and a drain of the first transistor, an output pin of the voltage stabilizing element is connected to a negative electrode of the corresponding battery cell, a gate driving pin of the voltage stabilizing element is connected to a gate of the first transistor, a source of the first transistor is connected to the negative electrode of the corresponding battery cell, and a positive electrode of the battery cell is connected to a positive electrode of the corresponding secondary winding; In the case that the first switch unit comprises the third transistor and the fourth transistor, a main power input pin of the voltage stabilization element is connected to the power supply module, a power input pin of the voltage stabilization element is connected to a negative electrode of the corresponding secondary winding and a drain electrode of the third transistor, a gate electrode of the third transistor is connected to a gate driving pin of the voltage stabilization element, a source electrode of the third transistor is connected to a drain electrode of the fourth transistor and an output pin of the voltage stabilization element, a gate electrode of the fourth transistor is connected to the power supply module, a source electrode of the fourth transistor is connected to a negative electrode of the corresponding battery cell, and a positive electrode of the battery cell is connected to a positive electrode of the corresponding secondary winding.

2. The circuit of claim 1, wherein, Each of the synchronous rectification modules comprises a rectification control unit and a first switch unit connected to each other; the corresponding secondary winding of the synchronous rectification module is connected to the corresponding battery cell of the synchronous rectification module through the first switch unit, and the rectification control unit is further connected to the corresponding channel selection module; The channel selection module of the target synchronous rectification module is configured to, in response to the enable signal, turn on 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 a working state. The rectification control unit is configured to, in the case that the rectification control unit is in the working state and the secondary winding in the flyback circuit is in a conducting state, turn on the charging path through the first switch unit.

3. The circuit of claim 1 or 2, characterized in that, The circuit further comprises a constant current module connected to the flyback circuit and the control module respectively. The constant current module is configured to acquire a primary side detection parameter of the flyback circuit, and in the case that the primary side detection parameter is greater than a target constant current parameter, control a duty cycle of the driving 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 as to make a charging parameter of the corresponding secondary winding of the target battery cell be within a preset charging parameter range.

4. The circuit of claim 3, wherein, The constant current module comprises a comparison unit and a gear adjustment unit, a non-inverting input terminal of the comparison unit is connected to the gear adjustment unit, an inverting input terminal of the comparison unit is configured to receive the primary side detection parameter, and an output terminal 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 a gear control signal in response to the gear control signal. The comparison unit is configured to acquire the primary side detection parameter, and in the case that 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 driving 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.

5. The circuit of claim 4, wherein, The gear adjustment unit comprises a first switch subunit and a resistance subunit, and the resistance subunit is connected to the first switch subunit and the non-inverting input terminal of the comparison unit respectively. The first switch subunit is configured to receive the gear control signal and adjust the resistance value of the resistance 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 value of the resistance subunit.

6. The circuit of claim 1 or 2, wherein The power supply module comprises a third switch unit, a fourth switch unit and at least one first energy storage unit. The third switch unit is connected to the input power supply and the fourth switch unit respectively. The first end of each first energy storage unit is connected to the third switch unit and the fourth switch unit respectively. The second end of each first energy storage unit is connected to a corresponding synchronous rectification module. The third switch unit is configured to, in response to the drive control signal, turn on a first path between the input power supply and each first energy storage unit when the drive control signal is the first level, so as to charge the first energy storage unit through the first path by the input power supply, and supply power to the corresponding synchronous rectification module based on the output voltage of the first energy storage unit. The fourth switch unit is configured to, in response to the drive control signal, turn off the first path and turn on a second path between the first energy storage unit and a ground terminal when the drive control signal is the first level, so as to discharge the energy of each first energy storage unit and stop supplying power to the corresponding synchronous rectification module.

7. The circuit of claim 1 or 2, wherein The circuit further comprises a starting module connected to the input power supply and the control module respectively. The starting module is configured to, in response to a starting signal, convert the input power supply into a starting voltage corresponding to the control module.

8. The circuit of claim 7, wherein, The starting module comprises a fifth switch unit and a second energy storage unit connected to each other. The fifth switch unit is connected to the input power supply, and the second energy storage unit is connected to the control module. The fifth switch unit is configured to, in response to the starting signal, turn on a second path between the input power supply and the second energy storage unit, so as to charge the second energy storage unit through the second path by the input power supply, and obtain the starting voltage based on the output voltage of the second energy storage unit.

9. The circuit of claim 8, wherein, The starting module further comprises a discharge unit connected to the fifth switch unit and the second energy storage unit respectively. The fifth switch unit is further configured to, in response to a stop starting signal, turn off the second path and discharge the energy of the second energy storage unit through the discharge unit.

10. An energy storage device, characterized by, The energy storage device comprises at least one battery cell and the equalization circuit according to any one of claims 1-9.

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