Balancing control circuit and method for a battery pack

Abstract

This invention provides a battery pack balancing control circuit and method. The balancing control circuit includes a battery pack, comprising at least a first cell and a second cell connected in series; a power supply module for converting the electrical energy of the battery pack into a working voltage and supplying it to a circuit load; a switching module disposed between the battery pack and the power supply module for selectively establishing energy transfer paths between the battery pack and the power supply module under different conduction states; a detection module for acquiring current signals in the energy transfer paths and voltage signals of the first and second cells; and a control module connected to the switching module, the power supply module, and the detection module, for determining the balancing direction based on the voltage difference between the first and second cells, controlling the switching module to establish the corresponding energy transfer path, enabling the first cell to release or replenish energy through the power supply module, and simultaneously controlling the energy transfer process based on the current signals to achieve battery pack balancing.

Description

Technical Field

[0001] This invention relates to the field of battery management technology, and in particular to a battery pack balancing control circuit and method. Background Technology

[0002] The battery management system (BMS) is a crucial component of new energy battery packs, used to monitor and manage the battery pack's operating status. This includes functions such as state of charge estimation, voltage and current monitoring, battery protection control, and communication management. In a battery pack composed of multiple cells connected in series, due to inconsistencies in the manufacturing and usage processes, capacity and voltage differences inevitably exist between the cells. This leads to uneven energy distribution within the battery pack, affecting overall performance. Therefore, battery balancing control plays a vital role in battery management.

[0003] In existing technologies, the most common equalization method is passive equalization, which typically uses power resistors to dissipate energy from high-capacity cells, gradually bringing the cell voltages closer together. However, this method directly converts electrical energy into heat for dissipation during energy processing, resulting in low energy utilization. Furthermore, the limited capacity of the power resistor restricts the equalization current, leading to a longer equalization process and greater heat accumulation during operation, which negatively impacts the battery system's temperature control and long-term reliability. Summary of the Invention

[0004] The purpose of this invention is to provide a battery pack equalization control circuit and method to solve the problems of low energy utilization, limited equalization current, and high heat generation in existing passive equalization battery management during the equalization process.

[0005] According to one aspect of the present invention, a battery pack equalization control circuit is provided, comprising: The battery pack includes at least a first cell and a second cell connected in series. A power supply module, connected to the battery pack, is used to convert the electrical energy of the battery pack into operating voltage and provide it to the circuit load; A switching module is disposed between the battery pack and the power supply module, and is used to selectively establish an energy transmission path between the battery pack and the power supply module under different conduction states; The detection module is connected to the battery pack, the switch module and the power supply module respectively, and is used to acquire the current signal in the energy transmission path and the voltage signals of the first cell and the second cell. The control module is connected to the switch module, the power supply module, and the detection module respectively. It is used to determine the balancing direction based on the voltage difference between the first cell and the second cell, control the switch module to establish the corresponding energy transmission path, so that the first cell can release or replenish energy through the power supply module, and control the energy transmission process based on the current signal to achieve the balancing of the battery pack.

[0006] In some embodiments, the control module is configured to: When the voltage of the first battery cell is lower than the voltage of the second battery cell and the voltage of the first battery cell is lower than the operating voltage output by the power supply module, the switching module is controlled to establish an energy transmission path from the power supply module to the first battery cell to replenish energy. When the voltage of the first battery cell is higher than the voltage of the second battery cell and the voltage of the first battery cell is higher than the minimum allowable input voltage of the power supply module, the switching module is controlled to establish an energy transmission path from the first battery cell through the power supply module for energy release.

[0007] In some embodiments, the control module is further configured to: Based on the current signal, the equalization current in the energy transmission path is integrated, and when the voltage of the first cell reaches or exceeds the working voltage output by the power supply module, or when the integration result reaches a preset equalization threshold, the switching module is controlled to disconnect the energy transmission path from the power supply module to the first cell for energy replenishment. When the voltage of the first battery cell reaches or falls below the minimum allowable input voltage of the power supply module, or when the integral calculation result reaches the preset equalization threshold, the switching module is controlled to disconnect the energy transmission path from the first battery cell through the power supply module.

[0008] In some embodiments, the equalization control circuit further includes: The reference voltage generation module includes a first operational amplifier, a first impedance element, a second impedance element, and a third impedance element. The non-inverting input of the first operational amplifier is connected to the output of the power supply module through the first impedance element. The non-inverting input of the first operational amplifier is also grounded through the second impedance element. The inverting input of the first operational amplifier is connected to the output of the first operational amplifier through the third impedance element. The output of the first operational amplifier outputs a reference voltage.

[0009] In some embodiments, the detection module includes a current detection unit, which includes a fourth impedance element, a fifth impedance element, a sixth impedance element, a seventh impedance element, an eighth impedance element, and a second operational amplifier. The first end of the fourth impedance element is connected between the first battery cell and the second battery cell through the switching module, and the second end of the fourth impedance element is connected to the input terminal of the power supply module. The non-inverting input of the second operational amplifier is connected to the first end of the fourth impedance element through the fifth impedance element, the inverting input is connected to the second end of the fourth impedance element through the sixth impedance element, and the output is connected to the control module. The non-inverting input of the second operational amplifier is also connected to the output of the reference voltage generation module through the seventh impedance element, and the inverting input is also connected to the output of the second operational amplifier through the eighth impedance element.

[0010] In some embodiments, the current detection unit further includes a ninth impedance element, a tenth impedance element, an eleventh impedance element, a twelfth impedance element, a thirteenth impedance element, and a third operational amplifier; The first end of the ninth impedance element is connected between the first battery cell and the second battery cell through the switching module, and the second end of the ninth impedance element is connected to the output end of the power supply module. The non-inverting input terminal of the third operational amplifier is connected to the second terminal of the ninth impedance element through the tenth impedance element, the inverting input terminal is connected to the first terminal of the ninth impedance element through the eleventh impedance element, and the output terminal is connected to the control module. The non-inverting input of the third operational amplifier is also connected to the output of the reference voltage generation module through the twelfth impedance element, and the inverting input is also connected to the output of the third operational amplifier through the thirteenth impedance element.

[0011] In some embodiments, the detection module includes a voltage detection unit, comprising a fourth operational amplifier, a fifth operational amplifier, a fourteenth impedance element, a fifteenth impedance element, a sixteenth impedance element, a seventeenth impedance element, an eighteenth impedance element, a nineteenth impedance element, a twentieth impedance element, and a twenty-first impedance element. The non-inverting input of the fourth operational amplifier is connected to the positive terminal of the second battery cell through the fourteenth impedance element. The non-inverting input of the fourth operational amplifier is also grounded through the fifteenth impedance element. The inverting input of the fourth operational amplifier is connected to the negative terminal of the second battery cell through the sixteenth impedance element. The inverting input of the fourth operational amplifier is also connected to the output of the fourth operational amplifier through the seventeenth impedance element. The output of the fourth operational amplifier is connected to the control module. The non-inverting input of the fifth operational amplifier is connected to the negative terminal of the second battery cell through the eighteenth impedance element. The non-inverting input of the fifth operational amplifier is also grounded through the nineteenth impedance element. The inverting input of the fifth operational amplifier is connected to the negative terminal of the first battery cell through the twentieth impedance element. The inverting input of the fifth operational amplifier is also connected to the output of the fifth operational amplifier through the twenty-first impedance element. The output of the fifth operational amplifier is connected to the control module.

[0012] In some embodiments, the switching module includes: The first switching unit has its first end connected to the positive terminal of the second battery cell, and its second end connected to the input terminal of the power supply module. The second switching unit has its first end connected between the first battery cell and the second battery cell, and its second end connected to the first end of the fourth impedance element. The third switching unit has its first end connected between the first battery cell and the second battery cell, and its second end connected to the first end of the ninth impedance element.

[0013] In some embodiments, the switch module further includes: The 22nd impedance element has its first end connected to the first end of the second switching unit, and its second end connected to the control end of the second switching unit. The 23rd impedance element has its first end connected to the first end of the third switching unit, and its second end connected to the control end of the third switching unit. A first driving unit, the first end of which is connected to the second end of the 22nd impedance element, and the second end of the first driving unit is connected to the control module; The second driving unit has its first end connected to the second end of the 23rd impedance element, and its second end connected to the control module.

[0014] Secondly, the present invention provides a battery pack equalization control method, applied to the aforementioned battery pack equalization control circuit, comprising: Obtain the voltage signals of the first and second battery cells, as well as the current signals in the energy transmission path; The balancing direction is determined based on the voltage difference between the first and second battery cells; When the voltage of the first battery cell is lower than the voltage of the second battery cell and the voltage of the first battery cell is lower than the operating voltage output by the power supply module, the control switch module establishes an energy transmission path from the power supply module to the first battery cell to replenish energy. When the voltage of the first battery cell is higher than the voltage of the second battery cell and the voltage of the first battery cell is higher than the minimum allowable input voltage of the power supply module, the control switch module establishes an energy transmission path from the first battery cell to the power supply module to release energy. The equalization current in the energy transmission path is integrated based on the current signal. When the voltage of the first battery cell reaches or exceeds the operating voltage output by the power supply module, or when the integral calculation result reaches the preset equalization threshold, the energy replenishment to the first battery cell is stopped. When the voltage of the first battery cell reaches or falls below the minimum allowable input voltage of the power supply module, or when the integral calculation result reaches the preset equalization threshold, the energy release to the first battery cell is stopped.

[0015] According to the present invention, by setting up a power supply module, a switching module, a detection module, and a control module, and by controlling the establishment of energy transmission paths based on the voltage difference between battery cells, the battery cells can release or replenish energy through the power supply module, thereby achieving balanced control of the battery pack. Compared with the traditional passive balancing method that consumes excess energy through balancing resistors, the present invention coordinates the system power supply path with the battery cell balancing process, enabling energy regulation between battery cells to be synchronized with the system load power supply, reducing energy loss and heat generation during the balancing process, improving the energy utilization rate of the battery pack, and reducing the use of high-power balancing resistors and heat dissipation structures, which helps to reduce system size and hardware costs.

[0016] Furthermore, by switching and controlling the energy transmission paths under different balancing directions, and combining balancing current detection, integral calculation, and threshold judgment mechanisms, closed-loop control of the cell energy replenishment and energy release processes is achieved, improving the accuracy and reliability of balancing control. Simultaneously, by setting up a reference voltage generation module, a current detection unit, and a voltage detection unit, real-time detection of the energy transmission status and balancing direction is achieved, enabling the identification and control of abnormal current states, thus improving the safety and stability of the balancing process. Moreover, this invention utilizes the system power supply module and load to participate in the balancing process, eliminating the need for an additional independent high-power energy dissipation branch, achieving battery pack balancing while simultaneously meeting system power supply requirements.

[0017] The above description is merely an overview of the technical solution of the present invention. In order to better understand the technical means of the present invention and to implement it in accordance with the contents of the specification, the preferred embodiments of the present invention are described in detail below. Attached Figure Description

[0018] Figure 1 A structural block diagram of a battery pack balancing control circuit according to an embodiment of the present invention is shown. Figure 2 A circuit topology diagram of a reference voltage generation module 60 according to an embodiment of the present invention is shown; Figure 3 A circuit topology diagram of a battery pack balancing control circuit according to an embodiment of the present invention is shown; Figure 4 A circuit topology diagram of a battery pack balancing control circuit according to another embodiment of the present invention is shown. Figure 5 A schematic flowchart of a battery pack balancing control method according to an embodiment of the present invention is shown. Detailed Implementation

[0019] To make the above-mentioned objectives, features, and advantages of this application more apparent and understandable, the specific embodiments of this application will be described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are for illustrative purposes only and are not intended to limit the scope of this application. Furthermore, it should be noted that, for ease of description, only the parts relevant to this application are shown in the accompanying drawings, not the entire structure. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without inventive effort are within the scope of protection of this application.

[0020] The terms “comprising” and “having”, and any variations thereof, used in this application are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or apparatus that includes a series of steps or units is not limited to the steps or units listed, but may optionally include steps or units not listed, or may optionally include other steps or units inherent to such process, method, product, or apparatus.

[0021] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0022] Figure 1 A structural block diagram of a battery pack balancing control circuit according to an embodiment of the present invention is shown. Figure 1As shown, the equalization control circuit includes a battery pack 10, a power supply module 30, a switch module 20, a detection module 50, and a control module 40. The battery pack 10 includes at least a first cell B1 and a second cell B2 connected in series. The power supply module 30 is connected to the battery pack 10 and converts the electrical energy of the battery pack 10 into a working voltage, which is then supplied to the circuit load. The switch module 20 is located between the battery pack 10 and the power supply module 30 and is used to selectively establish an energy transfer path between the battery pack 10 and the power supply module 30 under different conduction states. The detection module 50 is connected to the battery pack 10, the switch module 20, and the power supply module 30 respectively, and is used to acquire the current signal in the energy transfer path and the voltage signals of the first cell B1 and the second cell B2. The control module 40 is connected to the switch module 20, the power supply module 30 and the detection module 50 respectively. It is used to determine the balancing direction based on the voltage difference between the first cell B1 and the second cell B2, control the switch module 20 to establish the corresponding energy transmission path, so that the first cell B1 can release or replenish energy through the power supply module 30. At the same time, it controls the energy transmission process based on the current signal to achieve the balancing of the battery pack 10.

[0023] In this embodiment, the control module 40 can determine the balancing needs of the current battery pack 10 based on the voltage states of the first cell B1 and the second cell B2 obtained by the detection module 50. Combined with the output state and input conditions of the power supply module 30, it controls the switching state of the switch module 20 to establish corresponding energy transmission paths at different operating stages. Simultaneously, the detection module 50 can also detect the current state in the energy transmission path in real time to dynamically adjust and determine the state of the energy transmission process. Through this method, the original power supply path and the battery balancing path work in synergy, which not only reduces energy waste and heat generation caused by resistance during traditional passive balancing, but also effectively consumes the energy of the target cell using the system load, thereby improving the energy utilization rate and balancing efficiency of the battery pack 10.

[0024] According to the above embodiments, by setting up a power supply module 30, a switch module 20, a detection module 50, and a control module 40, and by controlling the establishment of energy transmission paths based on the voltage difference between battery cells, the battery cells can release or replenish energy through the power supply module 30, thereby achieving balanced control of the battery pack 10. Compared with the traditional passive balancing method that consumes excess energy through balancing resistors, this invention coordinates the system power supply path with the battery cell balancing process, enabling energy regulation between battery cells to be synchronized with the system load power supply. This reduces energy loss and heat generation during the balancing process, improves the energy utilization rate of the battery pack 10, and reduces the use of high-power balancing resistors and heat dissipation structures, which helps to reduce system size and hardware costs.

[0025] In one embodiment, the control module 40 is configured to, when the voltage of the first battery cell B1 is lower than the voltage of the second battery cell B2 and the voltage of the first battery cell B1 is lower than the operating voltage output by the power supply module 30, control the switch module 20 to establish an energy transmission path from the power supply module 30 to the first battery cell B1 for energy replenishment. When the voltage of the first battery cell B1 is higher than the voltage of the second battery cell B2 and the voltage of the first battery cell B1 is higher than the minimum allowable input voltage of the power supply module 30, control the switch module 20 to establish an energy transmission path from the first battery cell B1 to the power supply module 30 for energy release.

[0026] In this embodiment, the control module 40 not only determines the balancing direction based on the voltage difference between the first battery cell B1 and the second battery cell B2, but also judges the timing of establishing the energy transmission path by combining the output capability and input operating conditions of the power supply module 30. Specifically, when the voltage of the first battery cell B1 is lower than the voltage of the second battery cell B2, it indicates that the first battery cell B1 is in a state of relative energy deficiency and needs energy replenishment. Simultaneously, the control module 40 also determines whether the voltage of the first battery cell B1 is lower than the operating voltage output by the power supply module 30. This is because only when the operating voltage output by the power supply module 30 is higher than the terminal voltage of the first battery cell B1 can an effective voltage difference be formed between the output terminal of the power supply module 30 and the first battery cell B1, driving energy to be transferred from the power supply module 30 to the first battery cell B1. If the voltage of the first cell B1 is higher than or close to the operating voltage output by the power supply module 30, the power supply module 30 will be unable to continue to effectively charge the first cell B1, which may even lead to unstable energy transmission. Therefore, by introducing a comparison condition between the voltage of the first cell B1 and the operating voltage output by the power supply module 30, it is possible to ensure that the energy replenishment process has an effective transmission driving force.

[0027] Correspondingly, when the voltage of the first cell B1 is higher than that of the second cell B2, it indicates that the first cell B1 is in a relatively high energy state and needs to release energy. At this time, the control module 40 further determines whether the voltage of the first cell B1 is higher than the minimum allowable input voltage of the power supply module 30. This is because the power supply module 30 needs to meet the minimum input conditions to maintain stable operation and provide a stable operating voltage to the downstream circuit load. If the voltage of the first cell B1 is lower than the minimum allowable input voltage of the power supply module 30, the power supply module 30 may not be able to start normally or may have abnormal output, resulting in the energy release process being unstable. Therefore, by using the minimum allowable input voltage of the power supply module 30 as the condition for establishing the energy release path, the first cell B1 can maintain the stable operation of the power supply module 30 during the process of supplying energy to the power supply module 30, thereby enabling the energy released by the first cell B1 to be effectively utilized by the system load. Through the above method, the equalization control is not only related to the voltage difference between the cells, but also to the actual working capacity of the power supply module 30, thereby improving the stability, reliability, and energy utilization efficiency of the equalization process.

[0028] Furthermore, in this embodiment, the process of the power supply module 30 replenishing energy to the first battery cell B1 and the process of the first battery cell B1 releasing energy through the power supply module 30 employ different energy regulation methods. Specifically, when the charge of the first battery cell B1 is lower than that of the second battery cell B2, the second battery cell B2 can provide input energy to the power supply module 30 through the entire battery pack. This allows the power supply module 30 to replenish energy to the first battery cell B1 using its output voltage while maintaining the normal operation of the system load. Thus, the second battery cell B2 can indirectly compensate for the energy of the first battery cell B1 while participating in the system power supply.

[0029] Accordingly, when the charge of the first cell B1 is higher than that of the second cell B2, the conduction state of the switching module 20 is adjusted so that the first cell B1 prioritizes supplying power to the power supply module 30, and the system load prioritizes consuming the energy of the first cell B1. After the voltage of the first cell B1 gradually decreases and approaches the voltage of the second cell B2, the power supply to the power supply module 30 is restored to a state where the first cell B1 and the second cell B2 jointly supply power, thereby allowing the battery pack to re-enter a cooperative power supply state.

[0030] In this embodiment, instead of using a separate high-power balancing resistor to dissipate energy from high-capacity cells, or employing a complex bidirectional energy reinjection structure to directly transfer energy between cells, the system power supply process and the cell balancing process are designed in a coordinated manner. This reduces energy loss and heat generation during the balancing process and helps to reduce system complexity and hardware costs.

[0031] In one embodiment, the control module 40 is further configured to perform an integral calculation on the equalization current in the energy transmission path based on the current signal, and to control the switch module 20 to disconnect the energy transmission path from the power supply module 30 to the first battery cell B1 when the voltage of the first battery cell B1 reaches or exceeds the operating voltage output by the power supply module 30, or when the integral calculation result reaches a preset equalization threshold. Conversely, when the voltage of the first battery cell B1 reaches or falls below the minimum allowable input voltage of the power supply module 30, or when the integral calculation result reaches a preset equalization threshold, the control switch module 20 disconnects the energy transmission path from the first battery cell B1 to the power supply module 30 for energy release.

[0032] In this embodiment, after establishing the corresponding energy transmission path, the control module 40 also performs real-time acquisition and integration of the balancing current in the energy transmission path based on the current signal of the energy transmission path obtained by the detection module 50, in order to estimate the actual amount of electricity transmitted during the current balancing process. The integral result of the balancing current reflects the amount of energy transferred in the current balancing stage, and the control module 40 can judge the balancing progress in conjunction with a preset balancing threshold. When the first cell B1 is in an energy replenishment state, as energy continues to be transmitted, the terminal voltage of the first cell B1 gradually increases. When the voltage of the first cell B1 reaches or exceeds the operating voltage output by the power supply module 30, the effective voltage difference between the output terminal of the power supply module 30 and the first cell B1 gradually decreases, and the ability of the power supply module 30 to continue transmitting energy to the first cell B1 decreases accordingly. Continuing to maintain the energy replenishment path at this time may lead to a decrease in charging efficiency or unstable energy transmission. Therefore, the control module 40 controls the switch module 20 to disconnect the corresponding energy replenishment path. At the same time, even if the voltage of the first cell B1 has not yet reached the operating voltage output by the power supply module 30, as long as the integral calculation result reaches the preset equalization threshold, it can be considered that the expected energy compensation has been completed in the current equalization process, thereby ending the energy replenishment process in advance.

[0033] Correspondingly, when the first cell B1 is in the energy release state, the control module 40 also estimates the energy released by the first cell B1 by performing an integral calculation on the balancing current. As the first cell B1 continues to input energy into the power supply module 30, its terminal voltage gradually decreases. When the voltage of the first cell B1 reaches or falls below the minimum allowable input voltage of the power supply module 30, the ability of the power supply module 30 to maintain stable operation decreases, and continuing to maintain the energy release path may lead to abnormal output of the power supply module 30. Therefore, the control module 40 controls the switch module 20 to disconnect the corresponding energy release path. In addition, when the integral calculation result reaches the preset balancing threshold, it indicates that the current balancing process has completed the expected energy release. Even if the voltage of the first cell B1 has not yet dropped to the minimum allowable input voltage of the power supply module 30, the balancing process can be terminated. By using both the voltage condition and the integral calculation result as the balancing termination condition, this scheme can not only control the balancing process based on the cell voltage state, but also dynamically adjust the balancing process in combination with the actual energy transmission situation, thereby improving the accuracy and stability of balancing control and avoiding over-balancing or under-balancing problems caused by a single voltage judgment.

[0034] In one embodiment, the formula for estimating the cell charging and discharging time is: (|VB1-VB2| / VB2)×Q≈∫Idt. Where VB1 represents the voltage of the first cell B1, VB2 represents the voltage of the second cell B2, Q represents the cell capacity, and ∫Idt represents the integral result of the balancing current over time during the balancing process. Before balancing begins, the control module 40 estimates the target energy compensation amount corresponding to the current balancing process based on the voltage difference between the first cell B1 and the second cell B2 and the cell capacity. During the balancing process, the detection module 50 detects the balancing current in the energy transmission path in real time, and the control module 40 performs integration calculations based on the current signal to obtain the actual energy transmission amount completed. When the integration result reaches the corresponding target energy compensation amount, the control module 40 controls the switch module 20 to disconnect the corresponding energy transmission path and further compares the voltages of the first cell B1 and the second cell B2 to confirm whether the current balancing process is complete. By employing the above methods, the balancing termination condition can be determined not only based on the cell voltage state, but also dynamically controlled by combining the actual energy transmission situation, thereby improving the accuracy of balancing control.

[0035] In one embodiment, the equalization control circuit further includes a reference voltage generation module 60. Figure 2 A circuit topology diagram of a reference voltage generation module 60 according to an embodiment of the present invention is shown. Figure 2As shown, the reference voltage generation module 60 includes a first operational amplifier U1, a first impedance element R1, a second impedance element R2, and a third impedance element R3. The non-inverting input of the first operational amplifier U1 is connected to the output of the power supply module 30 through the first impedance element R1. The non-inverting input of the first operational amplifier U1 is also grounded through the second impedance element R2. The inverting input of the first operational amplifier U1 is connected to the output of the first operational amplifier U1 through the third impedance element R3. The output of the first operational amplifier U1 outputs a reference voltage V_REF.

[0036] In this embodiment, the operating voltage VCC output by the power supply module 30 is divided by the first impedance element R1 and the second impedance element R2 and then input to the non-inverting input terminal of the first operational amplifier U1. The first operational amplifier U1 forms a voltage follower feedback structure through the third impedance element R3, enabling the first operational amplifier U1 to output a stable reference voltage V_REF. The output reference voltage V_REF can be used as a bias voltage in the subsequent current detection unit 51, ensuring that the equalization current detection signal remains within the input range recognizable by the control module 40 in both charging and discharging states. Since there are two different energy transmission directions during the equalization process—energy replenishment from the power supply module 30 to the first battery cell B1 and energy release from the first battery cell B1 through the power supply module 30—the corresponding detection current directions also differ. By introducing the reference voltage V_REF, the current detection signal can be DC biased, allowing the control module 40 to identify the current energy transmission direction based on the change direction of the detection signal relative to the reference voltage, thereby distinguishing between charging and discharging states and judging abnormal states. The above methods not only improve the stability and recognition accuracy of equalization current detection, but also provide a reference for bidirectional current detection in the subsequent equalization control process.

[0037] In some embodiments, the first impedance element R1, the second impedance element R2, and the third impedance element R3 can each be a resistor composed of at least one impedance element. The first operational amplifier U1 can be implemented using an integrated operational amplifier device to generate a corresponding reference voltage V_REF based on the operating voltage output by the power supply module 30.

[0038] Figure 3 A circuit topology diagram of a battery pack balancing control circuit according to an embodiment of the present invention is shown. Figure 3As shown, the detection module 50 includes a current detection unit 51, used to detect the current in the energy transmission path and output the corresponding current signal. The current detection unit 51 includes a fourth impedance element R4, a fifth impedance element R5, a sixth impedance element R6, a seventh impedance element R7, an eighth impedance element R8, and a second operational amplifier U2. The first end of the fourth impedance element R4 is connected between the first battery cell B1 and the second battery cell B2 via the switch module 20, and the second end of the fourth impedance element R4 is connected to the input terminal of the power supply module 30. The non-inverting input terminal of the second operational amplifier U2 is connected to the first end of the fourth impedance element R4 via the fifth impedance element R5, the inverting input terminal is connected to the second end of the fourth impedance element R4 via the sixth impedance element R6, and the output terminal is connected to the control module 40. The non-inverting input terminal of the second operational amplifier U2 is also connected to the output terminal of the reference voltage generation module 60 via the seventh impedance element R7, and the inverting input terminal is also connected to the output terminal of the second operational amplifier U2 via the eighth impedance element R8.

[0039] In one embodiment, the current detection unit 51 further includes a ninth impedance element R9, a tenth impedance element R10, an eleventh impedance element R11, a twelfth impedance element R12, a thirteenth impedance element R13, and a third operational amplifier U3. The first terminal of the ninth impedance element R9 is connected between the first battery cell B1 and the second battery cell B2 via the switching module 20, and the second terminal of the ninth impedance element R9 is connected to the output terminal of the power supply module 30. The non-inverting input terminal of the third operational amplifier U3 is connected to the second terminal of the ninth impedance element R9 via the tenth impedance element R10, the inverting input terminal is connected to the first terminal of the ninth impedance element R9 via the eleventh impedance element R11, and the output terminal is connected to the control module 40. The non-inverting input terminal of the third operational amplifier U3 is also connected to the output terminal of the reference voltage generation module 60 via the twelfth impedance element R12, and the inverting input terminal is also connected to the output terminal of the third operational amplifier U3 via the thirteenth impedance element R13.

[0040] In the above embodiments, the current detection unit 51 is configured to correspond to both the energy release path and the energy replenishment path of the first battery cell B1. Specifically, the fourth impedance element R4 is disposed in the energy release path of the first battery cell B1 via the power supply module 30, and is used to sample the release current when the first battery cell B1 inputs energy to the power supply module 30; the ninth impedance element R9 is disposed in the energy replenishment path of the power supply module 30 to the first battery cell B1, and is used to sample the replenishment current when the power supply module 30 outputs energy to the first battery cell B1. Since the discharge path and the charging path of the first battery cell B1 are independent of each other, the corresponding current detection unit 51 detects the current in different energy transmission paths, thereby enabling the control module 40 to obtain the release current information during the discharge process and the charging current information during the replenishment process of the first battery cell B1.

[0041] Specifically, during the discharge process of the first cell B1, the first cell B1 inputs energy to the power supply module 30 via the switching module 20. A sampling voltage corresponding to the discharge current is generated across the fourth impedance element R4. The second operational amplifier U2 amplifies this sampling voltage and outputs it to the control module 40, enabling the control module 40 to detect the energy release state of the first cell B1. During the recharging process of the first cell B1, the power supply module 30 outputs energy to the first cell B1 via the switching module 20. A sampling voltage corresponding to the recharging current is generated across the ninth impedance element R9. The third operational amplifier U3 amplifies this sampling voltage and outputs it to the control module 40, enabling the control module 40 to detect the energy replenishment state of the first cell B1. Simultaneously, both the second operational amplifier U2 and the third operational amplifier U3 introduce the reference voltage output from the reference voltage generation module 60 as a bias reference, ensuring that the corresponding current detection signal remains within the input range recognizable by the control module 40, thereby improving the stability of the current detection process.

[0042] Furthermore, the control module 40 can perform integral calculations on the actual transmitted power during the equalization process based on the corresponding current detection signal to determine whether the current equalization process has reached the preset equalization threshold. Simultaneously, it can also verify the detected current state in conjunction with the currently established energy transmission path. For example, when the first cell B1 is in a charging state, the control module 40 detects the current signal in the charging path; when the first cell B1 is in a discharging state, the control module 40 detects the current signal in the discharging path. If the currently established energy transmission path does not correspond to the detected current state, it indicates that there may be abnormal conduction or abnormal energy transmission during the equalization process. In this case, the control module 40 can control the switch module 20 to stop the current equalization process, thereby improving the reliability and safety of the equalization control process.

[0043] In some embodiments, the fourth impedance element R4 to the thirteenth impedance element R13 can each be a resistor composed of at least one impedance element, used to realize voltage division, current sampling, bias introduction, and feedback adjustment functions between corresponding nodes. The second operational amplifier U2 and the third operational amplifier U3 can both be implemented using integrated operational amplifier devices.

[0044] In some embodiments, the fourth impedance element R4 and the ninth impedance element R9 can be replaced by Hall sensors with current detection function to achieve non-contact detection of the equalization current. Furthermore, the positions of the fourth impedance element R4 and the ninth impedance element R9 in the circuit can be adjusted according to specific design requirements, as long as it does not affect the current detection function and equalization control effect of the corresponding energy transmission path.

[0045] In one embodiment, reference Figure 3 The detection module 50 also includes a voltage detection unit 52, used to detect the voltage state of the first cell B1 and the second cell B2, and output corresponding voltage detection signals to the control module 40 for the control module 40 to determine the equalization direction and confirm the equalization state. The voltage detection unit 52 includes a fourth operational amplifier U4, a fifth operational amplifier U5, a fourteenth impedance element R14, a fifteenth impedance element R15, a sixteenth impedance element R16, a seventeenth impedance element R17, an eighteenth impedance element R18, a nineteenth impedance element R19, a twentieth impedance element R20, and a twenty-first impedance element R21. The non-inverting input of the fourth operational amplifier U4 is connected to the positive terminal of the second battery cell B2 through the fourteenth impedance element R14. The non-inverting input of the fourth operational amplifier U4 is also grounded through the fifteenth impedance element R15. The inverting input of the fourth operational amplifier U4 is connected to the negative terminal of the second battery cell B2 through the sixteenth impedance element R16. The inverting input of the fourth operational amplifier U4 is also connected to the output terminal of the fourth operational amplifier U4 through the seventeenth impedance element R17. The output terminal of the fourth operational amplifier U4 is connected to the control module 40. The non-inverting input of the fifth operational amplifier U5 is connected to the negative terminal of the second battery cell B2 through the eighteenth impedance element R18. The non-inverting input of the fifth operational amplifier U5 is also grounded through the nineteenth impedance element R19. The inverting input of the fifth operational amplifier U5 is connected to the negative terminal of the first battery cell B1 through the twentieth impedance element R20. The inverting input of the fifth operational amplifier U5 is also connected to the output terminal of the fifth operational amplifier U5 through the twenty-first impedance element R21. The output terminal of the fifth operational amplifier U5 is connected to the control module 40.

[0046] In this embodiment, the fourth operational amplifier U4 corresponds to the voltage detection circuit of the second cell B2. By sampling and amplifying the voltage across the second cell B2, it outputs a detection signal corresponding to the voltage of the second cell B2. The fifth operational amplifier U5 corresponds to the voltage detection circuit of the first cell B1. By sampling and amplifying the voltage across the first cell B1, it outputs a detection signal corresponding to the voltage of the first cell B1. The fourteenth impedance element R14, the fifteenth impedance element R15, the eighteenth impedance element R18, and the nineteenth impedance element R19 are used to construct the voltage sampling and biasing network for the corresponding input terminals. The seventeenth impedance element R17 and the twenty-first impedance element R21 are used to construct the feedback adjustment circuit for the corresponding operational amplifier to improve the stability of the voltage detection signal. The sixteenth impedance element R16 and the twentieth impedance element R20 are used to establish the corresponding differential detection path, enabling the fourth operational amplifier U4 and the fifth operational amplifier U5 to detect the voltage difference across the corresponding cell.

[0047] During the equalization process, due to the energy transfer current between the first cell B1 and the power supply module 30, the sampling circuits corresponding to the fourth operational amplifier U4 and the fifth operational amplifier U5 are affected by the equalization current and path voltage drop, resulting in deviations in the cell terminal voltage detection results. Therefore, the control module 40 can periodically control the switching module 20 to temporarily disconnect the corresponding energy transfer path during the equalization process and reserve a corresponding voltage sampling window, such as 20µs. During this time period, the equalization current in the energy transfer path decreases or disappears, and the voltage detection unit 52 samples the terminal voltages of the first cell B1 and the second cell B2, thereby reducing the impact of the equalization current on the voltage detection results and improving the accuracy of cell voltage detection. Through the above method, the control module 40 can still obtain relatively accurate cell voltage information during the equalization operation state, thereby improving the reliability of equalization direction judgment, equalization end judgment, and abnormal state detection.

[0048] In some embodiments, the fourteenth impedance element R14 to the twenty-first impedance element R21 can each be a resistor composed of at least one impedance element. The fourth operational amplifier U4 and the fifth operational amplifier U5 can both be implemented using integrated operational amplifier devices.

[0049] In one embodiment, reference Figure 3 The power supply module 30 is a regulated power supply, which can be a chip or a corresponding functional module. It is used to draw power from the battery pack 10 and output a corresponding operating voltage VCC, such as 3.3V, to provide operating power for the control module 40 and the detection module 50. The power supply module 30 can be implemented using a circuit with voltage regulation function, such as a single circuit or a combination circuit composed of devices such as a buck converter, a boost converter, a Zener diode, or a reference source.

[0050] The control module 40 is an MCU (Microcontroller Unit), the core processor of the battery management system. It processes the voltage and current signals output by the detection module 50 and controls the conduction state of the switch module 20 based on the corresponding detection results. The control module 40 can be implemented using different types of intelligent processors, such as a digital signal processor (DSP) or a processor-based control unit. In some embodiments, the control module 40 can also incorporate additional functional loads to participate in the energy consumption process, depending on system requirements.

[0051] In one embodiment, the control module 40, the first operational amplifier U1, the second operational amplifier U2, and the third operational amplifier U3 are connected to the power supply module 30 as system workloads to consume some of the energy during the equalization process. Compared to traditional passive equalization methods that directly convert excess energy into heat through equalization resistors, this invention utilizes the operating power consumption of the system's original functional circuits to participate in the cell equalization process, thereby reducing the need for additional equalization resistors and heat dissipation structures, improving the energy utilization rate of the battery pack 10, and reducing heat generation during the equalization process.

[0052] In one embodiment, reference Figure 3 The switching module 20 includes a first switching unit 21, a second switching unit 22, and a third switching unit 23. The first terminal of the first switching unit 21 is connected to the positive terminal of the second battery cell B2, and the second terminal of the first switching unit 21 is connected to the input terminal of the power supply module 30. The first terminal of the second switching unit 22 is connected between the first battery cell B1 and the second battery cell B2, and the second terminal of the second switching unit 22 is connected to the first terminal of a fourth impedance element. The first terminal of the third switching unit 23 is connected between the first battery cell B1 and the second battery cell B2, and the second terminal of the third switching unit 23 is connected to the first terminal of a ninth impedance element.

[0053] In this embodiment, the switching module 20 is used to switch different energy transmission paths under the control of the control module 40, so that the first cell B1 can release or replenish energy according to the current equilibrium state. Specifically, the first switching unit 21 controls the power supply connection between the battery pack 10 and the power supply module 30, the second switching unit 22 establishes the energy release path for the first cell B1, and the third switching unit 23 establishes the energy replenishment path for the first cell B1. Through the cooperation of these switching units, the switching between different operating states during the equilibrium process is achieved. When the system is operating normally, the first switching unit 21 is in the closed state, and the second and third switching units 22 are in the open state. The battery pack 10 provides operating power to the subsequent control module 40, operational amplifiers, and other system loads through the power supply module 30.

[0054] In one embodiment, reference Figure 3 The first switching unit 21 is the first switch S1, used to control the input power supply path of the power supply module 30. The second switching unit 22 is the second switch S2, used to establish the energy release path of the first battery cell B1. The third switching unit 23 is the third switch S3, used to establish the energy replenishment path of the first battery cell B1. The switches cooperate with each other to achieve the switching of energy transmission paths under different equilibrium states.

[0055] Figure 4 A circuit topology diagram of a battery pack balancing control circuit according to another embodiment of the present invention is shown. (Reference) Figure 4The second switching unit 22 and the third switching unit 23 are the first switching transistor Q1 and the second switching transistor Q2, respectively. By adopting a switching transistor structure, the corresponding energy transmission path can be quickly turned on and off under the control of the control module 40, thereby improving the switching speed and control stability during the equalization control process. Furthermore, during the equalization process, the control module 40 can also detect the conduction state of the first switching transistor Q1 and the second switching transistor Q2 based on the current detection result corresponding to the current sensing resistor. Among them, the control module 40 can estimate the drain-source voltage drop corresponding to the first switching transistor Q1 or the second switching transistor Q2 in combination with the equalization current in the current equalization path. If the actual conduction voltage drop of the corresponding switching transistor exceeds the preset threshold, it indicates that the corresponding switching transistor may have abnormal conduction, device damage, or abnormal drive. At this time, the control module 40 can control and stop the current equalization process, thereby improving the reliability and safety of the equalization control process.

[0056] In some embodiments, the first switching unit 21, the second switching unit 22, and the third switching unit 23 may be replaced by controllable switching devices such as bipolar transistors, relays, or metal-oxide-semiconductor field-effect transistors to achieve the on and off control of the corresponding energy transmission path.

[0057] In one embodiment, reference Figure 4 The switching module 20 also includes a twenty-second impedance element R22, a twenty-third impedance element R23, a first driving unit 24, and a second driving unit 25. The first end of the twenty-second impedance element is connected to the first end of the second switching unit 22, and the second end of the twenty-second impedance element is connected to the control terminal of the second switching unit 22. The first end of the twenty-third impedance element is connected to the first end of the third switching unit 23, and the second end of the twenty-third impedance element is connected to the control terminal of the third switching unit 23. The first end of the first driving unit 24 is connected to the second end of the twenty-second impedance element, and the second end of the first driving unit 24 is connected to the control module 40. The first end of the second driving unit 25 is connected to the second end of the twenty-third impedance element, and the second end of the second driving unit 25 is connected to the control module 40.

[0058] In this embodiment, the twenty-second impedance element R22 and the twenty-third impedance element R23 are respectively connected to the control terminals of the first switch Q1 and the second switch Q2, and are used to limit the current and drive the control signals of the corresponding switches. The first drive unit 24 and the second drive unit 25 are respectively connected to the control module 40, and are used to drive the corresponding switch unit to turn on or off according to the control signal output by the control module 40. The control signal output by the control module 40 is processed by the corresponding drive unit and then applied to the control terminal of the corresponding switch through the twenty-second impedance element R22 or the twenty-third impedance element R23 to control the establishment or disconnection of the corresponding energy transmission path. By setting the drive unit, the driving capability of the control module 40 on the corresponding switch unit can be improved, enabling the switch unit to achieve stable switching during the equalization process. At the same time, by setting the corresponding impedance element, the transient impact generated during the switching process can also be reduced, improving the stability of the switching control process.

[0059] In one embodiment, both the first driving unit 24 and the second driving unit 25 can be charge pump circuits, used to boost the voltage of the driving signal output by the control module 40 to meet the driving voltage requirements of the corresponding switching transistor, thereby improving the conduction reliability of the corresponding switching transistor.

[0060] The working principle of the equalization control circuit of this application will be described in detail below with reference to specific embodiments. See also Figure 2 and Figure 3 The first impedance element R1 to the twenty-first impedance element R21 are all resistors. The first switch unit 21 to the third switch unit 23 are switches S1 to S3, respectively.

[0061] The working principle of the equalization control circuit of the battery pack of the present invention is as follows: When the system is working normally, the first switch S1 is in the closed state, and the second switch S2 and the third switch S3 are in the open state. The positive terminal of the battery pack 10 provides working power to the downstream control module 40, each operational amplifier and other system loads through the power supply module 30. The control module 40 obtains the voltage information of the first cell B1 and the second cell B2 in real time, and determines whether equalization control is needed based on the corresponding voltage difference.

[0062] When the control module 40 detects that the voltage of the first cell B1 is lower than the voltage of the second cell B2, energy replenishment is required for the first cell B1. Since the operating voltage VCC output by the power supply module 30 needs to be higher than the terminal voltage of the first cell B1 to transfer energy to it, the control module 40 waits for the battery pack 10 to discharge until the voltage of the first cell B1 is lower than the operating voltage VCC before controlling the third switch S3 to close, thus establishing an energy transfer path for energy replenishment from the power supply module 30 to the first cell B1. During this process, the operating voltage VCC output by the power supply module 30 charges the first cell B1 through the corresponding path. The ninth impedance element R9 samples the equalization current in the replenishment path, and the third operational amplifier U3 amplifies the corresponding sampled signal and outputs it to the control module 40, enabling the control module 40 to obtain the current replenishment current information. As the replenishment process continues, the control module 40 performs integral calculations based on the corresponding current signal to estimate the amount of energy compensation already completed. When the voltage of the first cell B1 is detected to reach or exceed the operating voltage VCC, or when the integral calculation result reaches the preset equalization threshold, the control module 40 controls the third switch S3 to open, and further compares the voltages of the first cell B1 and the second cell B2 to confirm whether the current equalization process is complete.

[0063] When the control module 40 detects that the voltage of the first cell B1 is higher than the voltage of the second cell B2, energy needs to be released from the first cell B1. Since the power supply module 30 requires an input voltage higher than the minimum allowable input voltage to maintain stable operation, the control module 40 waits until the voltage of the first cell B1 is higher than the minimum allowable input voltage of the power supply module 30 before controlling the second switch S2 to close and the first switch S1 to open, thus establishing an energy transmission path from the first cell B1 through the power supply module 30 for energy release. During this process, the first cell B1 inputs energy to the power supply module 30, and the power supply module 30 supplies power to the system load, consuming some of the energy in the first cell B1. The fourth impedance element R4 samples the equalization current in the discharge path, and the second operational amplifier U2 amplifies the corresponding sampled signal and outputs it to the control module 40, enabling the control module 40 to obtain the current discharge current information. As the discharge process continues, the control module 40 performs integral calculations based on the corresponding current signal to estimate the amount of energy released so far. When the voltage of the first cell B1 is detected to be at or below the minimum allowable input voltage of the power supply module 30, or when the integral calculation result reaches the preset equalization threshold, the control module 40 controls the second switch S2 to open and the first switch S1 to close again to restore the normal power supply state of the system, and further compares the voltages of the first cell B1 and the second cell B2 to confirm whether the current equalization process is completed.

[0064] According to the above embodiments, by switching the energy transmission path under different balancing directions and combining balancing current detection, integral calculation, and threshold judgment mechanisms, closed-loop control of the cell energy replenishment and energy release processes is achieved, improving the accuracy and reliability of balancing control. Simultaneously, by setting up a reference voltage generation module 60, a current detection unit 51, and a voltage detection unit 52, real-time detection of the energy transmission status and balancing direction is achieved, enabling the identification and control of abnormal current states, thus improving the safety and stability of the balancing process. Furthermore, this invention utilizes the system power supply module 30 and the load to participate in the balancing process, eliminating the need for an additional independent high-power energy dissipation branch, achieving battery pack 10 balancing while simultaneously meeting system power supply requirements.

[0065] Figure 5 A schematic flowchart of a battery pack balancing control method according to an embodiment of the present invention is shown. Figure 5 As shown, the method includes the following steps: Step S100: Obtain the voltage signals of the first and second battery cells and the current signals in the energy transmission path.

[0066] Step S200: Determine the balancing direction based on the voltage difference between the first cell and the second cell.

[0067] In step S300, when the voltage of the first battery cell is lower than the voltage of the second battery cell and the voltage of the first battery cell is lower than the operating voltage output by the power supply module 30, the control switch module 20 establishes an energy transmission path from the power supply module 30 to the first battery cell to replenish energy. When the voltage of the first battery cell is higher than the voltage of the second battery cell and the voltage of the first battery cell is higher than the minimum allowable input voltage of the power supply module 30, the control switch module 20 establishes an energy transmission path from the first battery cell to the power supply module 30 to release energy.

[0068] Step S400: Perform an integral operation on the equalization current in the energy transmission path based on the current signal.

[0069] In step S500, when the voltage of the first battery cell reaches or exceeds the operating voltage output by the power supply module 30, or when the integral calculation result reaches the preset equalization threshold, the energy replenishment to the first battery cell is stopped; when the voltage of the first battery cell reaches or falls below the minimum allowable input voltage of the power supply module 30, or when the integral calculation result reaches the preset equalization threshold, the energy release to the first battery cell is stopped.

[0070] The specific implementation methods of each step in the above-described battery pack equalization control method refer to the relevant content of the embodiment in the above-described battery pack equalization control circuit, and will not be repeated here.

[0071] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0072] The above embodiments merely illustrate several implementation methods of the present invention, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims.

Claims

1. A battery pack equalization control circuit, characterized in that, include: The battery pack includes at least a first cell and a second cell connected in series. A power supply module, connected to the battery pack, is used to convert the electrical energy of the battery pack into operating voltage and provide it to the circuit load; A switching module is disposed between the battery pack and the power supply module, and is used to selectively establish an energy transmission path between the battery pack and the power supply module under different conduction states; The detection module is connected to the battery pack, the switch module and the power supply module respectively, and is used to acquire the current signal in the energy transmission path and the voltage signals of the first cell and the second cell. The control module is connected to the switch module, the power supply module, and the detection module respectively. It is used to determine the balancing direction based on the voltage difference between the first cell and the second cell, control the switch module to establish the corresponding energy transmission path, so that the first cell can release or replenish energy through the power supply module, and control the energy transmission process based on the current signal to achieve the balancing of the battery pack.

2. The battery pack equalization control circuit according to claim 1, characterized in that, The control module is configured as follows: When the voltage of the first battery cell is lower than the voltage of the second battery cell and the voltage of the first battery cell is lower than the operating voltage output by the power supply module, the switching module is controlled to establish an energy transmission path from the power supply module to the first battery cell to replenish energy. When the voltage of the first battery cell is higher than the voltage of the second battery cell and the voltage of the first battery cell is higher than the minimum allowable input voltage of the power supply module, the switching module is controlled to establish an energy transmission path from the first battery cell through the power supply module for energy release.

3. The battery pack equalization control circuit according to claim 2, characterized in that, The control module is also configured to: Based on the current signal, the equalization current in the energy transmission path is integrated, and when the voltage of the first cell reaches or exceeds the working voltage output by the power supply module, or when the integration result reaches a preset equalization threshold, the switching module is controlled to disconnect the energy transmission path from the power supply module to the first cell for energy replenishment. When the voltage of the first battery cell reaches or falls below the minimum allowable input voltage of the power supply module, or when the integral calculation result reaches the preset equalization threshold, the switching module is controlled to disconnect the energy transmission path from the first battery cell through the power supply module.

4. The battery pack equalization control circuit according to claim 3, characterized in that, The equalization control circuit also includes: The reference voltage generation module includes a first operational amplifier, a first impedance element, a second impedance element, and a third impedance element. The non-inverting input of the first operational amplifier is connected to the output of the power supply module through the first impedance element. The non-inverting input of the first operational amplifier is also grounded through the second impedance element. The inverting input of the first operational amplifier is connected to the output of the first operational amplifier through the third impedance element. The output of the first operational amplifier outputs a reference voltage.

5. The battery pack equalization control circuit according to claim 4, characterized in that, The detection module includes a current detection unit, which includes a fourth impedance element, a fifth impedance element, a sixth impedance element, a seventh impedance element, an eighth impedance element, and a second operational amplifier. The first end of the fourth impedance element is connected between the first battery cell and the second battery cell through the switching module, and the second end of the fourth impedance element is connected to the input terminal of the power supply module. The non-inverting input terminal of the second operational amplifier is connected to the first terminal of the fourth impedance element through the fifth impedance element, the inverting input terminal is connected to the second terminal of the fourth impedance element through the sixth impedance element, and the output terminal is connected to the control module. The non-inverting input of the second operational amplifier is also connected to the output of the reference voltage generation module through the seventh impedance element, and the inverting input is also connected to the output of the second operational amplifier through the eighth impedance element.

6. The battery pack equalization control circuit according to claim 5, characterized in that, The current detection unit also includes a ninth impedance element, a tenth impedance element, an eleventh impedance element, a twelfth impedance element, a thirteenth impedance element, and a third operational amplifier; The first end of the ninth impedance element is connected between the first battery cell and the second battery cell through the switching module, and the second end of the ninth impedance element is connected to the output end of the power supply module. The non-inverting input terminal of the third operational amplifier is connected to the second terminal of the ninth impedance element through the tenth impedance element, the inverting input terminal is connected to the first terminal of the ninth impedance element through the eleventh impedance element, and the output terminal is connected to the control module. The non-inverting input of the third operational amplifier is also connected to the output of the reference voltage generation module through the twelfth impedance element, and the inverting input is also connected to the output of the third operational amplifier through the thirteenth impedance element.

7. The battery pack equalization control circuit according to claim 6, characterized in that, The detection module includes a voltage detection unit, comprising a fourth operational amplifier, a fifth operational amplifier, a fourteenth impedance element, a fifteenth impedance element, a sixteenth impedance element, a seventeenth impedance element, an eighteenth impedance element, a nineteenth impedance element, a twentieth impedance element, and a twenty-first impedance element. The non-inverting input of the fourth operational amplifier is connected to the positive terminal of the second battery cell through the fourteenth impedance element. The non-inverting input of the fourth operational amplifier is also grounded through the fifteenth impedance element. The inverting input of the fourth operational amplifier is connected to the negative terminal of the second battery cell through the sixteenth impedance element. The inverting input of the fourth operational amplifier is also connected to the output of the fourth operational amplifier through the seventeenth impedance element. The output of the fourth operational amplifier is connected to the control module. The non-inverting input of the fifth operational amplifier is connected to the negative terminal of the second battery cell through the eighteenth impedance element. The non-inverting input of the fifth operational amplifier is also grounded through the nineteenth impedance element. The inverting input of the fifth operational amplifier is connected to the negative terminal of the first battery cell through the twentieth impedance element. The inverting input of the fifth operational amplifier is also connected to the output of the fifth operational amplifier through the twenty-first impedance element. The output of the fifth operational amplifier is connected to the control module.

8. The battery pack equalization control circuit according to claim 6 or 7, characterized in that, The switching module includes: The first switching unit has its first end connected to the positive terminal of the second battery cell, and its second end connected to the input terminal of the power supply module. The second switching unit has its first end connected between the first battery cell and the second battery cell, and its second end connected to the first end of the fourth impedance element. The third switching unit has its first end connected between the first battery cell and the second battery cell, and its second end connected to the first end of the ninth impedance element.

9. The battery pack equalization control circuit according to claim 8, characterized in that, The switching module also includes: The 22nd impedance element has its first end connected to the first end of the second switching unit, and its second end connected to the control end of the second switching unit. The 23rd impedance element has its first end connected to the first end of the third switching unit, and its second end connected to the control end of the third switching unit. A first driving unit, the first end of which is connected to the second end of the 22nd impedance element, and the second end of the first driving unit is connected to the control module; The second driving unit has its first end connected to the second end of the 23rd impedance element, and its second end connected to the control module.

10. A battery pack balancing control method, applied to the battery pack balancing control circuit according to any one of claims 1 to 9, characterized in that, include: Obtain the voltage signals of the first and second battery cells, as well as the current signals in the energy transmission path; The balancing direction is determined based on the voltage difference between the first and second battery cells; When the voltage of the first battery cell is lower than the voltage of the second battery cell and the voltage of the first battery cell is lower than the operating voltage output by the power supply module, the control switch module establishes an energy transmission path from the power supply module to the first battery cell to replenish energy. When the voltage of the first battery cell is higher than the voltage of the second battery cell and the voltage of the first battery cell is higher than the minimum allowable input voltage of the power supply module, the control switch module establishes an energy transmission path from the first battery cell to the power supply module to release energy. The equalization current in the energy transmission path is integrated based on the current signal. When the voltage of the first battery cell reaches or exceeds the operating voltage output by the power supply module, or when the integral calculation result reaches the preset equalization threshold, the energy replenishment to the first battery cell is stopped. When the voltage of the first battery cell reaches or falls below the minimum allowable input voltage of the power supply module, or when the integral calculation result reaches the preset equalization threshold, the energy release to the first battery cell is stopped.

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