Active equalization system and method of battery pack

Abstract

The embodiment of the invention provides an active equalization system and method of a battery pack, and relates to the technical field of battery management. The battery pack comprises n battery cells which are connected in parallel. The active equalization system comprises an auxiliary power supply, an isolation step-down circuit, a current limiting circuit, a voltage stabilizing circuit and n equalization control circuits, wherein the auxiliary power supply is sequentially connected with the isolation step-down circuit, the current limiting circuit and the voltage stabilizing circuit in series, and the equalization control circuits are respectively connected with battery cells in the battery pack in a one-to-one correspondence manner; and the equalization control circuit is used for controlling the communication state of the voltage stabilizing circuit and the battery cell according to the received control signal, so that the auxiliary power supply charges the battery cell needing to be charged. Through the active equalization system of the battery pack provided by the invention, the problem of non-uniform electric quantity of the battery cells in the battery pack can be effectively solved, the overall performance of the battery pack is improved, and the service life of the battery pack is prolonged.

Description

Technical Field

[0001] The present application relates to the field of battery management technology, and in particular to an active balancing system and method for a battery pack. Background Art

[0002] With the development of my country's energy storage business, the application of batteries is becoming more and more extensive. As the core component of energy storage and power supply, the performance and life of the battery pack directly affect the reliability and efficiency of the entire system. The battery pack is usually composed of multiple cells. Due to differences in manufacturing processes and usage conditions, these cells will inevitably have differences in battery capacity, charge state, internal resistance, voltage, etc. These differences will cause imbalance between cells during the charging and discharging process of the battery pack, thereby affecting the overall performance and life of the battery pack. Therefore, the electrical balancing technology of the battery pack has become a research focus.

[0003] At present, the balancing technology of battery packs is mainly divided into two categories: passive balancing and active balancing. Passive balancing mainly consumes the excess energy of high-energy cells by resistor discharge to achieve energy balancing; although this method is simple and easy, it has large energy loss and low efficiency. Active balancing mainly transfers energy from high-energy cells to low-energy cells through circuit control to achieve energy balancing. Compared with passive balancing, this method has higher efficiency and better balancing effect, but the energy utilization rate is relatively low, and the circuit structure is more complex and the cost is higher.

[0004] Therefore, how to reduce the inconsistency of each battery cell in a battery pack to improve the overall performance and safety of the battery is still a technical problem that needs to be solved urgently. Summary of the invention

[0005] The embodiments of the present application provide an active balancing system and method for a battery pack, so as to achieve the balance between the battery cells in the battery pack and improve the overall performance and safety of the battery.

[0006] In a first aspect, an embodiment of the present application provides an active balancing system for a battery pack, wherein the battery pack includes n parallel-connected cells, and the active balancing system includes: an auxiliary power supply, an isolated buck circuit, a current limiting circuit, a voltage stabilizing circuit, and n balancing control circuits;

[0007] The auxiliary power supply is connected in series with the isolation step-down circuit, the current limiting circuit and the voltage stabilizing circuit in sequence, and the balancing control circuit is connected to the cells in the battery pack one by one;

[0008] The balancing control circuit is used to control the connection state between the voltage stabilizing circuit and the battery cell according to the received control signal, so that the auxiliary power supply can charge the battery cell that needs to be supplemented.

[0009] In a possible implementation, the isolated step-down circuit includes a voltage regulator diode and a DC converter, the auxiliary power supply is connected to the input end of the DC converter through the voltage regulator diode, and the output end of the DC converter is connected to the current limiting circuit.

[0010] In a possible implementation, the current limiting circuit includes a first adjustable low-voltage dropout linear regulator and a first resistor, the input end of the first adjustable low-voltage dropout linear regulator is connected to the isolated step-down circuit, the output end of the first adjustable low-voltage dropout linear regulator is connected to one end of the first resistor, and the other end of the first resistor is connected to the voltage stabilization circuit.

[0011] In a possible implementation, the voltage stabilization circuit includes a second adjustable low voltage dropout linear regulator and a diode, the input end of the second adjustable low voltage dropout linear regulator is connected to the current limiting circuit, and the output end of the second adjustable low voltage dropout linear regulator is connected to the diode.

[0012] In a possible implementation, the balancing control circuit includes an optical coupler and a switch element, and the switch element includes a control end; one end of the optical coupler is connected to the battery cell, and the other end of the optical coupler is connected to the control end;

[0013] The optical coupler is used to receive a control signal and control the control end according to the control signal to control the connection state between the voltage stabilizing circuit and the battery cell, so that the auxiliary power supply can charge the battery cell that needs to be recharged.

[0014] In a possible implementation manner, the switch element includes a MOS tube, and a gate of the MOS tube is the control terminal.

[0015] In a possible implementation, the auxiliary power supply is used to output a 24V DC power supply.

[0016] In a possible implementation manner, the active balancing system further includes a detection unit, and the detection unit is connected to the balancing control circuit;

[0017] The detection unit is used to detect the power information of each battery cell in the battery pack, generate a control signal according to the power information, and send the control signal to the balancing control circuit.

[0018] In a possible implementation, the detection unit is specifically used to continuously detect the power information of each battery cell in the battery pack. When it is determined that the power difference between any battery cell and other battery cells is greater than a preset value, a conduction signal for controlling the battery cell is generated, and the conduction signal is sent to the balancing control circuit corresponding to the battery cell; when it is determined that the power difference between the battery cell and other battery cells is less than or equal to a preset value, a disconnection signal for controlling the battery cell is generated, and the disconnection signal is sent to the balancing control circuit corresponding to the battery cell.

[0019] In a second aspect, an embodiment of the present application provides an active balancing method for a battery pack, which is applied to a balancing control circuit in the first aspect and / or various possible active balancing systems in the first aspect, and the method includes:

[0020] A control signal is received, and according to the control signal, a connection state between the voltage stabilizing circuit and the battery cell is controlled so that the auxiliary power supply can charge the battery cell that needs to be charged.

[0021] In the active balancing system and method of the battery pack provided in the embodiment of the present application, the battery pack includes n parallel cells, and the active balancing system includes: an auxiliary power supply, an isolated buck circuit, a current limiting circuit, a voltage stabilizing circuit, and n balancing control circuits; wherein the auxiliary power supply is connected in series with the isolated buck circuit, the current limiting circuit, and the voltage stabilizing circuit in sequence, and the balancing control circuit is connected to the cells in the battery pack one by one; the balancing control circuit is used to control the connection state between the voltage stabilizing circuit and the cell according to the received control signal, so that the auxiliary power supply charges the cell that needs to be supplemented. The active balancing system of the battery pack provided in the embodiment of the present application can effectively solve the problem of uneven charge of the cells in the battery pack, realize active balanced charging of each cell in the battery pack, and improve the overall performance and service life of the battery pack; in addition, based on the design of the isolated buck circuit, the current limiting circuit, and the voltage stabilizing circuit, the safety and reliability of the active balancing system are also enhanced, which can further improve the stability and performance of the battery pack. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present application and, together with the description, serve to explain the principles of the present application.

[0023] Figure 1 A schematic diagram of the structure of an active equalization system for a battery pack provided in this application;

[0024] Figure 2 A flowchart of an active balancing method for a battery pack provided in an embodiment of the present application.

[0025] Reference numerals:

[0026] 10-auxiliary power supply; 20-isolation step-down circuit; 21-voltage regulator diode; 22-DC converter; 30-current limiting circuit; 31-first adjustable low-voltage difference linear regulator; 32-first resistor; 40-voltage regulator circuit; 41-second adjustable low-voltage difference linear regulator; 42-diode; 50-balance control circuit; 51-optical coupler; 52-switching element; 521-control end; 60-battery cell.

[0027] The above drawings have shown clear embodiments of the present application, which will be described in more detail later. These drawings and text descriptions are not intended to limit the scope of the present application in any way, but to illustrate the concept of the present application to those skilled in the art by referring to specific embodiments. DETAILED DESCRIPTION

[0028] Exemplary embodiments will be described in detail herein, examples of which are shown in the accompanying drawings. When the following description refers to the drawings, unless otherwise indicated, the same numbers in different drawings represent the same or similar elements. The implementations described in the following exemplary embodiments do not represent all implementations consistent with the present application. Instead, they are merely examples of devices and methods consistent with some aspects of the present application as detailed in the appended claims.

[0029] With the development of my country's energy storage business, the application of batteries is becoming more and more extensive. As the core component of energy storage and power supply, the performance and life of the battery pack directly affect the reliability and efficiency of the entire system. The battery pack is usually composed of multiple cells. Due to differences in manufacturing processes and usage conditions, these cells will inevitably have differences in battery capacity, charge state, internal resistance, voltage, etc. These differences will cause imbalance between cells during the charging and discharging process of the battery pack, thereby affecting the overall performance and life of the battery pack.

[0030] Although battery consistency cannot be completely eliminated, it can be minimized through battery balancing technology. In order to prevent the occurrence of large inconsistencies in battery cells, it is necessary to balance the different battery cells in a timely manner to reduce the impact of inconsistencies on the overall battery, avoid a vicious cycle, and improve the overall battery performance.

[0031] Currently, there are two common battery balancing technologies: passive balancing and active balancing.

[0032] The principle of passive balancing is to selectively discharge the cells with higher energy in the battery pack through the resistor in the loop, consume the high energy, reduce the gap between the cells, and finally reach a balanced state. Although the passive balancing circuit has a simple structure and low cost, the energy utilization rate is low, which not only causes energy waste, but also increases the heat generation of the battery module, thus affecting the battery life.

[0033] The principle of active balancing is to selectively transfer the energy of high-energy batteries in the battery pack to low-energy batteries to achieve energy transfer balancing, thereby reducing the gap between the cells and ultimately reaching a balanced state. Compared with passive balancing, active balancing is faster and has a higher energy utilization rate, but its circuit structure is relatively complex and the cost is also higher.

[0034] In order to solve the above problems, the embodiment of the present application provides an active balancing system for a battery pack, which performs energy compensation through an external power supply, thereby achieving power balancing. Specifically, the present application provides power through an auxiliary power supply, and isolates, limits the current, and stabilizes the electric energy output by the power supply through an isolation step-down circuit, a current limiting circuit, and a voltage stabilizing circuit, and then controls the power balancing by controlling the balancing control circuit, which better takes into account the overall energy of the battery, improves the balancing effect, and has a lower cost.

[0035] The technical solution of the present application and how the technical solution of the present application solves the above-mentioned technical problems are described in detail below with specific embodiments. The following specific embodiments can be combined with each other, and the same or similar concepts or processes may not be repeated in some embodiments. The embodiments of the present application will be described below in conjunction with the accompanying drawings.

[0036] Figure 1 A schematic diagram of the structure of an active equalization system for a battery pack provided in this application. Figure 1 As shown, the battery pack described in the embodiment of the present application includes n (3 in the figure) parallel-connected battery cells (BATTERY) 60. The active balancing system of the battery pack provided in the embodiment of the present application includes: an auxiliary power supply 10, an isolated buck circuit 20, a current limiting circuit 30, a voltage stabilizing circuit 40 and n (3 in the figure) balancing control circuits 50.

[0037] The auxiliary power supply 10 is connected in series with the isolation step-down circuit 20, the current limiting circuit 30 and the voltage stabilizing circuit 40 in sequence, and each balancing control circuit 50 is connected one-to-one with the battery cells 60 in the battery pack. The balancing control circuit 50 is used to control the connection state between the voltage stabilizing circuit 40 and the battery cell 60 according to the received control signal, so that the auxiliary power supply 10 charges the battery cell that needs to be supplemented.

[0038] Illustratively, the battery pack in the present application is composed of n parallel-connected battery cells. In the parallel circuit, the voltage is equal everywhere, and the total current is equal to the sum of each branch current. The parallel structure is usually used to increase the capacity and current output capability of the battery. For example, it can be applied to electric vehicles, energy storage systems and other scenarios.

[0039] In order to improve the overall performance and life of the battery pack, when the power difference between the battery cells in the battery pack is large and power balancing is required, the active balancing system based on the embodiment of the present application can be used to charge the battery cells that need to be replenished to reduce the power difference between the battery cells.

[0040] It should be noted that the auxiliary power supply 10 can be an independent power supply such as a battery pack, or it can be AC ​​power, which is used to provide additional power to the battery cells in the battery pack that need to be recharged to achieve power balance. The isolated step-down circuit 20 is used to reduce the output voltage of the auxiliary power supply 10 to a level suitable for charging the battery cells, while providing electrical isolation to improve safety. The current limiting circuit 30 is used to limit the current passing through the circuit to prevent overcurrent from damaging the battery cells or circuits. The voltage stabilizing circuit 40 is used to ensure that the output voltage is stable so as to provide a stable charging voltage for the battery cells. The balancing control circuit 50 is used to control the charging state of the battery cells until their power reaches the expected balanced state.

[0041] For example, when a battery cell in the battery pack needs to be recharged, the balancing control circuit corresponding to the battery cell will receive a signal to control its conduction, and then the balancing control circuit will control the voltage stabilizing circuit 40 to be connected to the battery cell that needs to be recharged, so that the auxiliary power supply 10 can charge the battery cell that needs to be recharged; and when the difference between the battery cell and other battery cells is less than or equal to the preset limit, that is, when the power reaches the expected balanced state, the corresponding balancing control circuit will receive a disconnect signal. At this time, the balancing control circuit will control the voltage stabilizing circuit 40 to disconnect from the battery cell that needs to be recharged, so that the auxiliary power supply 10 stops charging the battery cell.

[0042] In the active balancing system of the battery pack provided in the embodiment of the present application, the battery pack includes n parallel cells, and the active balancing system includes: an auxiliary power supply, an isolated buck circuit, a current limiting circuit, a voltage stabilizing circuit, and n balancing control circuits; wherein the auxiliary power supply is connected in series with the isolated buck circuit, the current limiting circuit, and the voltage stabilizing circuit in sequence, and the balancing control circuit is connected one-to-one with the cells in the battery pack respectively; the balancing control circuit is used to control the connectivity between the voltage stabilizing circuit and the cells according to the received control signal, so that the auxiliary power supply charges the cells that need to be supplemented. Based on the active balancing system of the battery pack provided in the embodiment of the present application, the problem of uneven charge of the cells in the battery pack can be effectively solved, and the active balancing charging of each cell in the battery pack can be realized, thereby improving the overall performance and service life of the battery pack; in addition, based on the design of the isolated buck circuit, the current limiting circuit, and the voltage stabilizing circuit, the safety and reliability of the active balancing system are also enhanced, which can further improve the stability and performance of the battery pack.

[0043] Optionally, based on the above embodiment, in a possible embodiment, the auxiliary power supply 10 is used to output a 24V DC power supply.

[0044] For example, in the embodiment of the present application, the function of the auxiliary power supply 10 is to provide a stable power supply for the entire equalization system. By providing a relatively high voltage, the auxiliary power supply 10 can provide sufficient power for the cells in the battery pack to achieve fast and effective equalization charging. 24V is a common industrial standard voltage, which is widely used in various electrical and electronic equipment. The mains or battery pack is selected as the input, and the 24V DC power supply is selected as the output, which makes the design and integration of the system simpler and more economical. In addition, the 24V voltage can also be effectively converted into a voltage suitable for charging the battery cell through a DC converter. According to different battery cell voltage requirements, the voltage can be flexibly adjusted through the DC converter to achieve a higher conversion efficiency. In short, using a 24V DC power supply as an auxiliary power supply can not only provide stable, efficient and flexible power support for the entire active equalization system, but also ensure that the battery cells in the battery pack can be charged safely and evenly.

[0045] Optionally, based on the above embodiment, in a possible embodiment, as Figure 1 As shown, the isolated step-down circuit 20 may include a voltage regulator diode 21 and a DC converter 22. The auxiliary power supply 10 is connected to the input end of the DC converter 22 through the voltage regulator diode 21, and the output end of the DC converter 22 is connected to the current limiting circuit 30.

[0046] Exemplarily, the voltage zener diode 21 is used to provide a stable voltage reference in the circuit and provide protection when the voltage fluctuates. When the voltage exceeds its breakdown voltage, the voltage zener diode 21 will turn on and keep the output voltage at a constant level.

[0047] The DC-DC converter 22 is used to convert the input DC voltage into a desired output voltage. For example, it can be a step-down type, which is used to reduce a higher input voltage to a level suitable for charging the battery cell.

[0048] In the present application, the voltage stabilizing diode 21 is connected between the auxiliary power supply 10 and the input end of the DC converter 22, and the output end of the DC converter 22 is connected to the current limiting circuit 30. In this way, the 24V DC power output by the auxiliary power supply 10 will first pass through the voltage stabilizing diode 21 and the DC converter 22, and then reach the current limiting circuit 30, which can not only ensure that the voltage input to the DC converter 22 does not exceed the safety level, but also the voltage adjusted by the voltage stabilizing diode 21 can be further converted by the DC converter 22 into a voltage suitable for charging the battery cell.

[0049] Based on the Zener diode and DC converter, the isolated buck circuit can not only provide stable voltage and current, but also achieve electrical isolation to protect the entire system from voltage fluctuations and overcurrent, thereby improving the safety and reliability of the system, while ensuring that the charging process of the battery cell is efficient and stable.

[0050] Optionally, based on the above embodiment, in a possible embodiment, as Figure 1 As shown, the current limiting circuit 30 includes a first adjustable low voltage dropout linear regulator 31 and a first resistor 32, the input end of the first adjustable low voltage dropout linear regulator 31 is connected to the isolation step-down circuit 20, the output end of the first adjustable low voltage dropout linear regulator 31 is connected to one end of the first resistor 32, and the other end of the first resistor 32 is connected to the voltage stabilization circuit 40.

[0051] Exemplarily, an adjustable low dropout linear regulator (LDO) is used to provide a stable output voltage according to actual needs. At the same time, it has a low voltage difference characteristic, which means that it can work normally when the difference between the input voltage and the output voltage is very small. The resistor is used to limit the current. According to Ohm's law, voltage V = current I × resistance R, the size of the resistor determines the amount of current passing through the circuit. By selecting a suitable resistance value, the current flowing through the battery cell can be accurately controlled to prevent overcurrent from causing damage to the battery cell. This application does not limit the size of the first resistor, which can be set according to the actual needs of the battery cell.

[0052] In the embodiment of the present application, the input end of the first adjustable low-voltage dropout linear regulator 31 is connected to the output end of the isolated buck circuit 20, and the first resistor 32 is connected between the output end of the first adjustable low-voltage dropout linear regulator 31 and the voltage stabilizing circuit 40. In this way, after receiving the voltage regulated by the voltage stabilizing diode 21 and the DC converter 22 in the isolated buck circuit 20, the first adjustable low-voltage dropout linear regulator 31 will further perform voltage stabilization operations and set a voltage level suitable for charging the battery cell through its adjustable function, while the first resistor 32 will limit the output current within a safe range under the condition of voltage stability, and finally send the current that has been reduced in isolation and current limiting to the voltage stabilizing circuit 40.

[0053] Through the combination of an adjustable low-dropout linear regulator and a resistor, the current limiting circuit can not only provide a stable voltage, but also adapt to the needs of different battery cells, achieve precise current control, protect the battery cells from overcurrent, and extend the life of the battery cells while ensuring that the battery cells are evenly charged under safe conditions. This precise current management is essential for protecting the battery cells and improving the overall performance of the battery pack.

[0054] Optionally, based on the above embodiment, in a possible embodiment, as Figure 1 As shown, the voltage stabilizing circuit 40 includes a second adjustable low voltage dropout linear regulator 41 and a diode 42 . The input end of the second adjustable low voltage dropout linear regulator 41 is connected to the current limiting circuit 30 , and the output end of the second adjustable low voltage dropout linear regulator 41 is connected to the diode 42 .

[0055] Exemplarily, the main function of the voltage regulator circuit 40 is to provide a stable output voltage. By using a low-dropout linear regulator, a small voltage difference can be maintained between the input voltage and the output voltage, thereby improving efficiency. The present application uses an adjustable low-dropout linear regulator LDO, and can also set the output voltage through an external resistor or voltage according to the actual needs of the battery cell in the battery pack to achieve flexible voltage regulation. The diode has unidirectional conductivity, which can prevent reverse current from damaging the regulator and other circuit components.

[0056] In the embodiment of the present application, the input end of the second adjustable low voltage drop linear regulator 41 is connected to the current limiting circuit 30, and the output end is connected to the diode 42. In this way, the current that has been limited by the current limiting circuit 30 will be stabilized again by the second adjustable low voltage drop linear regulator 41, so as to flow into the subsequent circuit in a unidirectional manner.

[0057] Based on the design of adjustable low voltage drop linear regulator and diode, the voltage stabilization circuit can not only prevent the reverse current from damaging the regulator and other circuit components, but also provide a more stable input power supply for the cells in the battery pack and improve the active balancing effect.

[0058] Optionally, based on the above embodiment, in a possible embodiment, as Figure 1 As shown, the balancing control circuit 50 includes an optical coupler 51 and a switch element 52, and the switch element 52 includes a control terminal 521; one end of the optical coupler 51 is connected to the battery cell 60, and the other end of the optical coupler 51 is connected to the control terminal 521. The optical coupler 51 is used to receive a control signal and control the control terminal 521 according to the control signal to control the connection state between the voltage stabilizing circuit 40 and the battery cell 60, so that the auxiliary power supply 10 charges the battery cell 60 that needs to be supplemented.

[0059] For example, an optocoupler is a device that can be used for electrical isolation. It transmits control information through optical signals to ensure that there is no direct electrical connection between the input and output to prevent high voltage or noise interference. A switching element is an electronic component that can be turned on or off by a control signal. For example, a switching element can be a transistor. In each balancing control circuit, multiple switching elements and resistors can be set according to the actual circuit design requirements to accurately control the connectivity between the voltage stabilization circuit and the battery cell. Figure 1 As shown, 4 switching elements and 4 resistors can be set.

[0060] In the embodiment of the present application, one end of the optocoupler 51 is connected to the battery cell 60, and the other end of the optocoupler 51 is connected to the control end 521 of each switch element 52. When the optocoupler 51 receives the control signal, the control end 521 of each switch element 52 is controlled according to the control signal to control the connection state between the voltage stabilizing circuit 40 and the battery cell 60. If the control signal is a conduction signal, the control end 521 of the switch element 52 is controlled to connect the voltage stabilizing circuit 40 and the battery cell 60, and the auxiliary power supply 10 starts to charge the battery cell 60; if the control signal is a disconnection signal, the control end 521 of the switch element 52 is controlled to disconnect the voltage stabilizing circuit 40 from the battery cell 60, and the auxiliary power supply 10 stops charging the battery cell 60.

[0061] Through the cooperation of optocouplers and switch elements, the balancing control circuit can adjust the voltage of each battery cell and achieve balancing of each battery cell in the battery pack, thereby improving the performance and reliability of the battery pack.

[0062] Optionally, based on the above embodiment, in a possible embodiment, the switch element 52 includes a MOS tube, and the gate of the MOS tube is the control terminal 521 .

[0063] For example, a MOS tube is a commonly used switching element, which has high input impedance and fast switching speed, and is very suitable for switching control of a circuit. The switching element in the present application can use a MOS tube, each of which includes a source, a drain, and a gate. The gate is the control end of the MOS tube, and the on or off of the MOS tube can be controlled by applying a voltage.

[0064] In the embodiment of the present application, the output end of the optocoupler 51 is connected to the gate of the MOS tube. When a battery cell needs to be charged, the optocoupler 51 outputs a high-level signal, the gate voltage of the MOS tube increases, the MOS tube is turned on, and current is allowed to flow from the source to the drain, thereby achieving conduction between the voltage stabilizing circuit 40 and the battery cell to allow the auxiliary power supply 10 to charge the battery cell; when it is no longer necessary to continue charging a battery cell, the optocoupler 51 outputs a low-level signal, the gate voltage of the MOS tube decreases, the MOS tube is turned off, and current is prevented from flowing. The voltage stabilizing circuit 40 and the battery cell are disconnected, and the auxiliary power supply 10 stops charging the battery cell.

[0065] MOS tubes have the advantages of fast response speed, low power consumption and long service life. Using MOS tubes as switching elements combined with the electrical isolation characteristics of optocouplers can achieve precise control of the charging status of the battery cells and ensure the voltage balance and overall performance of the battery pack.

[0066] Optionally, based on the above embodiment, in a possible embodiment, the active balancing system may further include a detection unit ( Figure 1(not shown), the detection unit is connected to each balancing control circuit; the detection unit is used to detect the power information of each battery cell in the battery pack, generate a control signal according to the power information, and send the control signal to the balancing control circuit.

[0067] Exemplarily, the balancing control circuit needs to control the connectivity between the voltage stabilizing circuit and the battery cell according to a control signal. Therefore, the active balancing system in the embodiment of the present application may further include a detection unit, which is responsible for real-time monitoring of the power information of each battery cell in the battery pack and analyzing the collected data to determine the power difference between the battery cells.

[0068] Exemplarily, the detection unit can estimate the charge state by directly measuring parameters such as voltage, current, temperature, etc. or using more complex algorithms, and then analyze the charge data of each battery cell, identify the imbalance of charge, and then generate a corresponding control signal based on the analysis result. The signal is sent to the corresponding balancing control circuit. When the corresponding balancing control circuit receives the control signal, the charging control or stopping of the charging control of the specific battery cell can be realized through the control of the optocoupler and the MOS tube, thereby achieving the purpose of charge balance.

[0069] By introducing the detection unit, real-time monitoring and dynamic balancing control of each battery cell in the battery pack can be achieved, improving the performance and reliability of the battery pack; in addition, through the coordinated work of the detection unit and the balancing control circuit, the system can automatically adjust the charging and discharging strategy to ensure that the voltage of the battery cell remains within the ideal range.

[0070] Optionally, based on the above embodiments, in a possible embodiment, the detection unit is specifically used to continuously detect the power information of each battery cell in the battery pack, and when it is determined that the power difference between any battery cell and other battery cells is greater than a preset value, a conduction signal is generated to control the battery cell, and the conduction signal is sent to the balancing control circuit corresponding to the battery cell; when it is determined that the power difference between the battery cell and other battery cells is less than or equal to a preset value, a disconnection signal is generated to control the battery cell, and the disconnection signal is sent to the balancing control circuit corresponding to the battery cell.

[0071] It can be understood that the control signal includes a conduction signal and a disconnection signal. The detection unit will generate a corresponding signal and send it to the corresponding balancing control circuit according to the actual monitoring result. During the continuous detection process, the detection unit will calculate the difference in charge between each battery cell and other battery cells, where the charge difference refers to the difference between the charge of a certain battery cell and the average charge of other battery cells in the battery pack or a certain reference charge. The preset value is a threshold value used to determine whether the charge difference is large enough to require a balancing operation. The embodiment of the present application does not limit the specific value of the preset value.

[0072] For example, when the detection unit determines that the power difference between a certain battery cell and other battery cells is greater than a preset value, it means that the power of the battery cell is significantly lower than that of other battery cells and needs to be charged to achieve balance. At this time, the detection unit will generate a conduction signal. When the power difference is less than or equal to the preset value, it means that the power of the battery cells has been basically balanced and no longer needs to be charged. At this time, the detection unit will generate a disconnection signal.

[0073] The detection unit will also send the generated conduction signal or disconnection signal to the balancing control circuit corresponding to the battery cell. After receiving the conduction signal, the corresponding balancing control circuit will connect the voltage stabilizing circuit and the battery cell to enable the auxiliary power supply to charge the battery cell. After receiving the disconnection signal, the voltage stabilizing circuit and the battery cell will be disconnected to control the auxiliary power supply to stop charging the battery cell.

[0074] By monitoring the power information of each battery cell in real time and making dynamic adjustments through the detection unit, the power status of each battery cell can be accurately controlled, and the imbalanced power situation can be quickly responded to. Adjustments can be made in time to avoid overcharging or over-discharging of the battery cells, thereby extending the service life of the battery pack and improving the overall performance and reliability of the battery pack.

[0075] It can be understood that in circuit design, in order to enable the circuit to operate normally and accurately, capacitors C, resistors and other circuit elements are usually set at required positions. The embodiments of the present application do not limit this. The present application aims to effectively solve the problem of uneven charge of battery cells in the battery pack through the active balancing system of the battery pack provided in the embodiments of the present application, so as to realize active balanced charging of each battery cell in the battery pack, and also improve the overall performance and service life of the battery pack.

[0076] Figure 2 The active balancing method for a battery pack provided in an embodiment of the present application is a flow chart of the active balancing method for a battery pack provided in an embodiment of the present application, and is applied to a balancing control circuit in any of the above-mentioned active balancing systems, such as Figure 2 As shown, the method may include:

[0077] S201. Receive a control signal.

[0078] S202: According to the control signal, control the connection state between the voltage stabilizing circuit and the battery cell, so that the auxiliary power supply can charge the battery cell that needs to be recharged.

[0079] Exemplarily, the active balancing system of the embodiment of the present application is intended to solve the problem of uneven charge of each battery cell in a battery pack. Its core is to manage the charging process of the battery cell by receiving control signals, control the charge of each battery cell to remain within a reasonable range, and thus achieve charge balance of the battery pack.

[0080] In combination with the above embodiments, it can be known that the generation of the control signal can rely on the detection unit's continuous monitoring and analysis of the power information of each battery cell in the battery pack. When the detection unit determines that the power difference between a certain battery cell and other battery cells is greater than a preset value, it will generate a conduction signal and send the generated conduction signal to the balancing control circuit corresponding to the battery cell; and when it is determined that the power difference between a certain battery cell and other battery cells is less than or equal to the preset value, it will generate a disconnection signal and send the generated disconnection signal to the balancing control circuit corresponding to the battery cell.

[0081] The balancing control circuit will also receive the on signal or off signal sent by the detection unit accordingly. When receiving the on signal, the balancing control circuit will connect the voltage stabilizing circuit with the corresponding battery cell so that the auxiliary power supply can charge the battery cell. When receiving the off signal, the voltage stabilizing circuit and the battery cell will be disconnected to control the auxiliary power supply to stop charging the battery cell.

[0082] Among them, the auxiliary power supply can be an independent power supply such as a battery pack, or it can be AC ​​power. When the auxiliary power supply charges the battery cell, the auxiliary power supply can output a 24V DC power supply; then, the isolation step-down circuit will perform a step-down isolation operation to reduce the output voltage of the auxiliary power supply to a level suitable for charging the battery cell, while providing electrical isolation to improve safety; further, the current limiting circuit can limit the current through the circuit through the characteristics of the adjustable low-dropout linear regulator and the resistor connected in series with the output pin to prevent overcurrent from damaging the battery cell or circuit; finally, the voltage stabilization circuit will again stabilize the voltage through the adjustable low-dropout linear regulator to ensure that the battery cell can obtain a suitable voltage until the battery cell reaches the expected balanced state. When the battery cell reaches the expected balanced state, the balancing control circuit will receive a disconnect signal, and then the balancing control circuit will control the voltage stabilization circuit to disconnect from the battery cell so that the auxiliary power supply stops charging the battery cell.

[0083] The active equalization method of the battery pack provided in the embodiment of the present application is applied to the equalization control circuit in any of the above-mentioned active equalization systems. The equalization control circuit can receive a control signal and control the connection state between the voltage stabilization circuit and the battery cell according to the control signal, so that the auxiliary power supply can charge the battery cell that needs to be recharged. By accurately controlling the charging process of the battery cell, not only can the risk of overcharging or over-discharging of the battery cell be reduced, but also the power balance of the battery pack is achieved, which also helps to extend the service life of the battery pack and improve the performance and reliability of the battery pack.

[0084] Finally, it should be noted that those skilled in the art will readily conceive of other embodiments of the present invention after considering the specification and practicing the invention disclosed herein. The present invention is intended to cover any variations, uses or adaptations of the present invention, which follow the general principles of the present invention and include common knowledge or customary technical means in the art not disclosed by the present invention, are not limited to the precise structure described above and shown in the drawings, and may be modified and changed in various ways without departing from the scope thereof. The scope of the present invention is limited only by the appended claims.

Claims

1. An active equalization system for a battery pack, characterized in that: The battery pack includes n parallel-connected cells, and the active balancing system includes: an auxiliary power supply, an isolated voltage-reducing circuit, a current-limiting circuit, a voltage-stabilizing circuit, and n balancing control circuits; The auxiliary power supply is connected in series with the isolation step-down circuit, the current limiting circuit and the voltage stabilizing circuit in sequence, and the balancing control circuit is connected to the cells in the battery pack one by one; The balancing control circuit is used to control the connection state between the voltage stabilizing circuit and the battery cell according to the received control signal, so that the auxiliary power supply can charge the battery cell that needs to be supplemented.

2. The active balancing system according to claim 1, characterized in that: The isolated step-down circuit includes a voltage-stabilizing diode and a DC converter. The auxiliary power supply is connected to the input end of the DC converter through the voltage-stabilizing diode, and the output end of the DC converter is connected to the current limiting circuit.

3. The active balancing system according to claim 1, characterized in that: The current limiting circuit includes a first adjustable low-voltage dropout linear regulator and a first resistor, wherein the input end of the first adjustable low-voltage dropout linear regulator is connected to the isolated step-down circuit, the output end of the first adjustable low-voltage dropout linear regulator is connected to one end of the first resistor, and the other end of the first resistor is connected to the voltage stabilization circuit.

4. The active balancing system according to claim 1, characterized in that: The voltage stabilization circuit includes a second adjustable low voltage dropout linear regulator and a diode, the input end of the second adjustable low voltage dropout linear regulator is connected to the current limiting circuit, and the output end of the second adjustable low voltage dropout linear regulator is connected to the diode.

5. The active balancing system according to claim 1, characterized in that: The balancing control circuit includes an optical coupler and a switch element, and the switch element includes a control end; one end of the optical coupler is connected to the battery cell, and the other end of the optical coupler is connected to the control end; The optical coupler is used to receive a control signal and control the control end according to the control signal to control the connection state between the voltage stabilizing circuit and the battery cell, so that the auxiliary power supply can charge the battery cell that needs to be recharged.

6. The active balancing system according to claim 5, characterized in that: The switch element comprises a MOS tube, and the gate of the MOS tube is the control terminal.

7. The active balancing system according to claim 1, characterized in that: The auxiliary power supply is used to output a 24V DC power supply.

8. The active balancing system according to any one of claims 1 to 7, characterized in that: The active balancing system further comprises a detection unit, wherein the detection unit is connected to each of the balancing control circuits; The detection unit is used to detect the power information of each battery cell in the battery pack, generate a control signal according to the power information, and send the control signal to the balancing control circuit.

9. The active balancing system according to claim 8, characterized in that: The detection unit is specifically used to continuously detect the power information of each battery cell in the battery pack. When it is determined that the power difference between any battery cell and the other battery cells is greater than a preset value, a conduction signal for controlling the battery cell is generated, and the conduction signal is sent to the balancing control circuit corresponding to the battery cell; when it is determined that the power difference between the battery cell and the other battery cells is less than or equal to a preset value, a disconnection signal for controlling the battery cell is generated, and the disconnection signal is sent to the balancing control circuit corresponding to the battery cell.

10. An active balancing method for a battery pack, characterized in that: The method applied to the equalization control circuit in the active equalization system according to any one of claims 1 to 9 comprises: A control signal is received, and according to the control signal, a connection state between the voltage stabilizing circuit and the battery cell is controlled so that the auxiliary power supply can charge the battery cell that needs to be charged.

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