Capacitive battery active equalization circuit and method thereof

Abstract

The invention discloses a capacitive battery active equalization circuit and a method thereof. The capacitive battery active equalization circuit comprises a plurality of single batteries, a power MOS (Metal Oxide Semiconductor) tube circuit, an energy storage circuit and a control loop, the control loop comprises an ADC module, a PID module, a constant current controller and a power MOS tube driving module. The corresponding end of the ADC module is electrically connected with the corresponding ends of the plurality of single batteries and the PID module; the corresponding end of the PID module is connected with the corresponding end of the power MOS tube driving module through the constant current controller; and the corresponding end of the power MOS tube driving module is electrically connected with the corresponding end of the power MOS tube circuit. Compared with the scheme in the current market, the device has the advantages of low cost, small size, easiness in integration, simplicity in control, high safety and the like, and can store the energy of the battery with high voltage to the capacitor and carry the energy stored on the capacitor to the battery with low voltage, so that the aim of balancing the electric quantity of the battery is fulfilled.

Description

Technical Field

[0001] The present invention relates to the technical field of battery management, and in particular to a capacitor type battery active equalization circuit and method thereof. Background Art

[0002] In the field of battery management system (BMS), battery pack balancing technology is the key to ensure the long-term stable operation of the battery pack. Battery packs are usually composed of multiple single cells connected in series or parallel. Due to manufacturing differences, aging inconsistencies, and temperature and load differences during use, the voltage and state of charge (SoC) of these single cells may gradually differ. If not controlled, this difference will cause the battery pack performance to deteriorate and may even cause the battery to overcharge or over-discharge, thus affecting the battery life and safety.

[0003] Currently, active balancing circuits on the market mainly use inductors as energy storage elements. Their working principle is to temporarily store excess energy through inductors and then release it back to the batteries with lower voltages in the battery pack. However, this inductor-based balancing circuit has the following technical problems: Cost issue: The cost of inductive components is relatively high, especially for battery systems that require large current balancing, which requires the use of high-power, high-quality inductors, which further increases the cost of the system.

[0004] Size and integration issues: Inductive components are usually large, which limits the application of balancing circuits in compact spaces, especially in areas such as portable electronic devices and electric vehicles.

[0005] Safety risks: The inductor may produce reverse charging during the energy transfer process, that is, the low-voltage battery releases energy to the high-voltage battery, which not only reduces the balancing efficiency, but may also cause battery overcharging and increase safety risks.

[0006] Efficiency issues: Inductors generate heat during energy transfer, resulting in energy loss and reducing the overall efficiency of the system. Summary of the invention

[0007] In view of the problems existing in the prior art, the present invention provides a capacitor type battery active balancing circuit and method thereof.

[0008] The present invention provides a capacitor type battery active equalization circuit, comprising: a plurality of single cells, a power MOS tube circuit, an energy storage circuit, and a control loop; The control loop includes an ADC module, a PID module, a constant current controller and a power MOS tube driving module; the corresponding end of the ADC module is electrically connected to a plurality of single cells and a corresponding end of the PID module respectively; the corresponding end of the PID module is connected to a corresponding end of the power MOS tube driving module via a constant current controller; the corresponding end of the power MOS tube driving module is electrically connected to a corresponding end of a power MOS tube circuit, and the corresponding end of the power MOS tube circuit is also connected to a plurality of single cells and a corresponding end of an energy storage circuit respectively.

[0009] Preferably, the plurality of single cells include single cells BAT1 and single cells BAT2; the ADC module includes ADC1 and ADC2, wherein ADC1 is used to collect the voltage VBAT1 of the single cell BAT1, and ADC2 is used to collect the voltage VBAT2 of the single cell BAT2.

[0010] Preferably, the PID module is used to calculate the absolute value ΔV=|VBAT2 − VBAT1| of the voltage difference between the single battery BAT1 and the single battery BAT2, and output a control signal to adjust the battery balancing process.

[0011] Preferably, the constant current controller adjusts the switching frequency f of the power MOS tube circuit according to the output signal of the PID module. SW Or charging time T D , to control the rate at which the energy storage circuit transfers energy to the low-voltage battery cells.

[0012] Preferably, the power MOS tube driving module is used to drive the MOS tube circuit to control the energy transfer between the single battery BAT1 and the single battery BAT2.

[0013] Preferably, the power MOS tube circuit includes MOS tube Q1, MOS tube Q2, MOS tube Q3, and MOS tube Q4; The source of the MOS tube Q1 is electrically connected to the positive electrode of the single battery BAT2, the drain of the MOS tube Q1 is electrically connected to the first end of the energy storage circuit and the drain of the MOS tube Q2 respectively, and the gate of the MOS tube Q1 is electrically connected to the corresponding end of the power MOS tube driving module; The source of the MOS tube Q2 is electrically connected to the negative electrode of the single battery BAT2, the positive electrode of the single battery BAT1, and the source of the MOS tube Q3, respectively, and the gate of the MOS tube Q2 is electrically connected to the corresponding end of the power MOS tube driving module; The drain of the MOS tube Q3 is electrically connected to the second end of the energy storage circuit and the drain of the MOS tube Q4 respectively, and the gate of the MOS tube Q3 is electrically connected to the corresponding end of the power MOS tube driving module; The source of the MOS transistor Q4 is electrically connected to the negative electrode of the single cell BAT1 and grounded, and the gate of the MOS transistor Q4 is electrically connected to the corresponding terminal of the power MOS transistor drive module.

[0014] Preferably, the energy storage circuit includes an energy storage capacitor C1, which is used to temporarily store the energy from the high-voltage battery cell and transfer this energy to the low-voltage battery cell when needed.

[0015] The present invention also provides a capacitive battery active balancing method for the capacitive battery active balancing circuit, including any one of the following methods: Method 1: Step A1: Turn on the MOS transistors Q1 and Q3 to connect the single cell BAT2 in parallel with the energy storage capacitor C1, and the voltage of the energy storage capacitor C1 is VBAT2; Step A2: Turn on the MOS transistors Q2 and Q3 to connect the single cell BAT1 in parallel with the energy storage capacitor C1, and the voltage of the energy storage capacitor C1 is VBAT1; Step A3: Calculate the charge quantity Q transferred by the energy storage capacitor C1 within an equalization period, Q = |VBAT2 - VBAT1| * C1 = ΔV * C1; Step A4: Calculate the average equalization current I AVG , I AVG = Q * f SW = ΔV * C1 * f SW , and control f SW to maintain I AVG constant, where f SW is the switching frequency of the power MOS transistor; Method 2: Step S1: Measure the voltages VBAT1 and VBAT2 of the body cell BAT1 and the single cell BAT2; Step S2: Control the MOS transistor circuit to charge the energy storage circuit according to the magnitudes of VBAT1 and VBAT2; Step S3: Calculate the average equalization current I AVG , and control the charging time T D to maintain I AVG constant.

[0016] Preferably, in step S2, when VBAT2 > VBAT1, control the gate G1 of the power MOS transistor Q1 so that the MOS transistor Q1 charges the capacitor C1 with the current I H and the power MOS transistor Q3 is fully turned on; When VBAT2 < VBAT1, control the gate G4 of the power MOS transistor Q4 so that the MOS transistor Q4 uses the current IH The capacitor C1 is charged and the power MOS tube Q2 is fully turned on.

[0017] Preferably, in step S3, the formula for the average balancing current is: AVG = Q / T = I H * T D / T,T D = I AVG *T / I H , where Q is the charge transferred by the energy storage capacitor C1, I H is the charging current of the capacitor, T D is the charging time of the capacitor, and T is the switching period.

[0018] The technical solution of the present invention has the following beneficial effects: Compared with the current solutions on the market, the present invention has the advantages of low cost, small size, easy integration, simple control, and high safety. It can store the energy of high-voltage batteries on capacitors, and transfer the energy stored on capacitors to low-voltage batteries, thereby achieving the purpose of battery power balance. The present invention reduces system cost: using capacitors as energy storage elements can significantly reduce the cost of equalization circuits compared to inductor elements, making the battery management system more economical and efficient.

[0019] The present invention reduces the volume of the system: the capacitance element is small in volume, making the entire equalization circuit more compact and convenient for integration into space-constrained equipment.

[0020] The present invention can prevent reverse charging: the present invention ensures that energy can only be transferred from the high-voltage battery to the low-voltage battery through a specific control strategy, effectively avoiding the "reverse charging phenomenon" in which the low-voltage battery releases energy to the high-voltage battery, thereby improving the safety of the system, and reducing the risk of battery overcharging by avoiding the reverse charging phenomenon, thereby reducing the incidence of safety accidents.

[0021] The present invention can achieve rapid balancing: through the rapid switching characteristics and precise control of the power MOS tube, rapid balancing between battery cells is achieved, thereby improving the balancing efficiency.

[0022] The present invention can perform precise control: the ADC module is used to monitor the battery voltage in real time, the PID module is used to accurately calculate the voltage difference, and a control signal is output, thereby achieving precise control of the battery balancing process; precise control of the charging process helps to reduce heat loss caused by current fluctuations and maintain the temperature stability of the battery system.

[0023] The single cell of the present invention is the main body of energy storage and release. Through active balancing, the service life of the battery pack can be effectively extended to prevent performance degradation or damage caused by voltage imbalance between battery cells. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 Schematic diagram of the circuit of the present invention. DETAILED DESCRIPTION

[0025] The present invention is further described below in conjunction with the accompanying drawings and specific embodiments.

[0026] Reference Figure 1 The present invention provides a capacitor type battery active balancing circuit, comprising: a single cell BAT1 100 and a single cell BAT2 200, a power MOS tube circuit 300, an energy storage circuit 400, and a control loop 500; The control loop 500 includes an ADC module, a PID module, a constant current controller and a power MOS tube driving module; the corresponding end of the ADC module is electrically connected to the single battery BAT1 100 and the single battery BAT2 200, and the corresponding end of the PID module; the corresponding end of the PID module is connected to the corresponding end of the power MOS tube driving module through the constant current controller; the corresponding end of the power MOS tube driving module is electrically connected to the corresponding end of the power MOS tube circuit 300, and the corresponding end of the power MOS tube circuit 300 is also connected to the corresponding end of the single battery BAT1 100 and the single battery BAT2 200, and the energy storage circuit 400; Among them, the single battery BAT1 and the single battery BAT2 are the main bodies of energy storage and release. Through active balancing, the service life of the battery pack can be effectively extended to prevent performance degradation or damage caused by voltage imbalance between battery cells; As an efficient electronic switch, the power MOS tube circuit 300 (MOS tubes Q1, Q2, Q3, Q4) can quickly respond to the control signal to achieve rapid energy transfer between the battery cells (BAT1 and BAT2) and the energy storage capacitor. This rapid response helps to improve the balancing efficiency and the overall performance of the system. The control loop 500 is the brain of the entire balancing circuit, responsible for monitoring, calculating and regulating the power balancing process between battery cells. Through precise control, it can ensure that the voltage balancing between battery cells is carried out within a safe and efficient range. The ADC module (including ADC1 and ADC2) is responsible for real-time monitoring of the voltage of the battery cells and providing accurate voltage data for the control loop. This real-time monitoring helps to timely detect voltage imbalance and take corresponding balancing measures. The PID module calculates the voltage difference between battery cells based on the voltage data provided by the ADC module, and outputs a control signal to adjust the power balancing process, improve the response speed and stability of the system, and reduce overshoot and oscillation. The constant current controller adjusts the switching frequency or charging time of the power MOS tube according to the output signal of the PID module to control the rate at which the energy storage capacitor transfers energy to the low-voltage battery cell. This precise energy control helps to protect the battery cell from damage caused by overcharging or over-discharging. The power MOS tube drive module is responsible for driving the MOS tube circuit to control the energy transfer between the single cells. This drive control can ensure the accuracy and reliability of energy transfer and improve the efficiency and safety of the system.

[0027] Furthermore, the ADC module includes ADC1 and ADC2, wherein ADC1 is used to collect the voltage VBAT1 of the single cell BAT1, and ADC2 is used to collect the voltage VBAT2 of the single cell BAT2, to provide accurate voltage data and enable accurate voltage monitoring; ADC1 and ADC2 can collect data in real time, and by real-time monitoring of voltage changes by ADC1 and ADC2, the system can timely capture slight differences in battery voltages and provide real-time data support for subsequent balancing control. Through the data collected by ADC1 and ADC2, the system can accurately evaluate the status of each battery cell, thereby optimizing the management of the battery pack and extending the battery life.

[0028] Furthermore, the PID module is used to calculate the absolute value ΔV=|VBAT2 - VBAT1| of the voltage difference between the single cell BAT1 and the single cell BAT2. According to the calculated voltage difference ΔV, the PID module outputs a corresponding control signal to dynamically adjust the switching state of the power MOS tube to regulate the power balancing process and ensure the voltage balance between the battery cells. By accurately controlling the voltage difference between the battery cells, the PID module helps to avoid battery damage or safety risks caused by voltage imbalance; by maintaining the voltage balance between the battery cells, the PID module helps to prevent the battery from being overcharged or over-discharged, thereby extending the battery life.

[0029] Furthermore, the constant current controller adjusts the switching frequency f of the power MOS tube circuit according to the output signal of the PID module. SW Or charging time T D, in order to control the rate at which the energy storage circuit transfers energy to the low-voltage battery cell, and to achieve precise control of the rate at which the energy storage circuit transfers energy to the low-voltage battery cell; by adjusting the switching frequency f SW Or charging time T D The constant current controller can maintain the constant average balancing current IAVG, ensure the stable power balancing process between battery cells, and avoid battery damage caused by current fluctuations.

[0030] Furthermore, the power MOS tube driving module is used to drive the MOS tube circuit to control the energy transfer between the single battery BAT1 and the single battery BAT2.

[0031] Furthermore, the power MOS tube circuit includes MOS tube Q1, MOS tube Q2, MOS tube Q3, and MOS tube Q4; The source of the MOS tube Q1 is electrically connected to the positive electrode of the single battery BAT2, the drain of the MOS tube Q1 is electrically connected to the first end of the energy storage circuit and the drain of the MOS tube Q2, and the gate of the MOS tube Q1 is electrically connected to the corresponding end of the power MOS tube driving module; the source of the MOS tube Q2 is electrically connected to the negative electrode of the single battery BAT2, the positive electrode of the single battery BAT1, and the source of the MOS tube Q3, and the gate of the MOS tube Q2 is electrically connected to the corresponding end of the power MOS tube driving module; the drain of the MOS tube Q3 is electrically connected to the second end of the energy storage circuit and the drain of the MOS tube Q4, and the gate of the MOS tube Q3 is electrically connected to the corresponding end of the power MOS tube driving module. The source of the MOS tube Q4 is electrically connected to the negative electrode of the single battery BAT1 and is grounded, and the gate of the MOS tube Q4 is electrically connected to the corresponding end of the power MOS tube driving module; in this embodiment, the MOS tubes Q1 to Q4 act as efficient electronic switches, which can accurately control the energy flow between the battery cells BAT1 and BAT2 and the energy storage capacitor C1; the power MOS tube can quickly respond to the control signal, realize the fast switching of energy transfer between the battery cells, and improve the balancing speed; by controlling the switching state of the MOS tube, the battery can be prevented from being overcharged or over-discharged, and the stability of the entire battery system can be enhanced; the battery charging and discharging process is accurately controlled, the battery damage is reduced, and it is helpful to extend the battery life.

[0032] Furthermore, the energy storage circuit includes an energy storage capacitor C1, which is used to temporarily store energy from high-voltage battery cells and transfer the energy to low-voltage battery cells when needed; the energy storage capacitor C1 has the characteristics of fast charging and discharging, which makes the energy transfer process rapid and efficient, and helps to improve the speed and efficiency of battery balancing. By storing and releasing energy, capacitor C1 helps to maintain the voltage balance of each single battery in the battery pack and prevent performance degradation due to excessive voltage differences. Capacitor C1 reduces the voltage difference between battery cells, reduces the risk of battery damage due to voltage imbalance, and improves the overall reliability of the battery pack. By reducing overcharging and over-discharging of battery cells, capacitor C1 helps to extend the service life of the battery.

[0033] The present invention provides a capacitor type battery active equalization method, which is used in the capacitor type battery active equalization circuit, and includes any of the following methods: Method 1: Step A1: Turn on MOS tubes Q1 and Q3 to connect the single battery BAT2 and the energy storage capacitor C1 in parallel, and the voltage of the energy storage capacitor C1 is VBAT2; by turning on MOS tubes Q1 and Q3, the single battery BAT2 and the energy storage capacitor C1 are connected in parallel, so that the energy storage capacitor C1 can absorb or release energy from BAT2, thereby starting the energy transfer process. This step realizes the synchronization of the voltage of the energy storage capacitor C1 and the voltage of BAT2, laying the foundation for the subsequent balancing operation.

[0034] Step A2: The power MOS tube Q2 and the MOS tube Q3 are turned on, so that the single battery BAT1 is connected in parallel with the energy storage capacitor C1, and the voltage of the energy storage capacitor C1 is VBAT1; this step allows the energy storage capacitor C1 to transfer energy to BAT1 or receive energy from BAT1 as needed, further promoting voltage balance between battery cells.

[0035] Step A3, calculate the charge amount Q carried by the energy storage capacitor C1 in one balancing cycle, Q = |VBAT2 - VBAT1| * C1 = ΔV * C1; this step provides accurate data support for subsequent current control by quantifying the charge transfer amount, ensuring the accuracy of energy transfer and the effectiveness of the balancing process.

[0036] Step A4: Calculate the average balancing current I AVG , I AVG = Q *f SW = ΔV * C1 *f SW , and control f SW To maintain I AVG constant, where f SW is the switching frequency of the power MOS tube; by adjusting the switching frequency f of the power MOS tube SW, precisely control the rate of energy transfer from the high-voltage battery to the low-voltage battery, maintain the stability of the balancing current, thereby achieving voltage balance among battery cells and improving the overall performance and lifespan of the battery pack; Method 2: Step S1: Measure the voltages VBAT1 and VBAT2 of the single-cell battery BAT1 and the single-cell battery BAT2; obtain the real-time voltage status of the battery cells; Step S2: According to the magnitudes of VBAT1 and VBAT2, control the MOS transistor circuit to charge the energy storage circuit; achieve the transfer of energy from the high-voltage battery to the low-voltage battery, which helps reduce the voltage difference among battery cells and maintain the balanced state of the battery pack; Step S3: Calculate the average balancing current I AVG , and control the charging time T D to maintain I AVG constant; by precisely controlling the charging time, ensure the stability of energy transfer and the consistency of the balancing current, thereby improving the efficiency and effect of battery balancing.

[0037] Furthermore, in Step S2, when VBAT2 > VBAT1, control the gate G1 of the power MOS transistor Q1 so that the MOS transistor Q1 charges the capacitor C1 with the current I H , and the power MOS transistor Q3 is fully turned on; ensure the low impedance of the charging path and reduce energy loss.

[0038] When VBAT2 < VBAT1, control the gate G4 of the power MOS transistor Q4 so that the MOS transistor Q4 charges the capacitor C1 with the current I H , and the power MOS transistor Q2 is fully turned on; ensure the low impedance of the charging path and reduce energy loss.

[0039] Furthermore, in Step S3, the formula for the average balancing current is I AVG = Q / T = I H * T D / T, T D = I AVG * T / I H , where Q is the amount of charge transferred by the energy storage capacitor C1, I H is the charging current of the capacitor, T D is the charging time of the capacitor, T is the switching period. According to Step S3, it can be known that the capacitor charging time T D is inversely proportional to the capacitor charging current I H . By controlling the charging time T H according to the magnitude of the charging current I D can achieve the constancy of the average balancing current I AVG . By precisely calculating and controlling the charging time TD , ensuring the average balanced current I AVG Keep constant to achieve precise control of energy transfer between battery cells. Constant balancing current helps improve the efficiency of battery balancing, reduce energy loss, and speed up the balancing process. By precisely controlling the charging current and time, the risk of overcharging and over-discharging of the battery is reduced, and the battery life is extended. Precise energy transfer control reduces energy loss during the transfer process and improves the energy utilization efficiency of the battery system.

[0040] It can be seen from the above embodiments that the present invention has the advantages of low cost, small size, easy integration, simple control, high safety, etc. compared with the current solutions on the market; it can store the energy of the high-voltage battery on the capacitor, and transfer the energy stored on the capacitor to the low-voltage battery, so as to achieve the purpose of battery power balancing; The present invention reduces system cost: using capacitors as energy storage elements can significantly reduce the cost of equalization circuits compared to inductor elements, making the battery management system more economical and efficient.

[0041] The present invention reduces the volume of the system: the capacitance element is small in volume, making the entire equalization circuit more compact and convenient for integration into space-constrained equipment.

[0042] The present invention can prevent reverse charging: the present invention ensures that energy can only be transferred from the high-voltage battery to the low-voltage battery through a specific control strategy, effectively avoiding the "reverse charging phenomenon" in which the low-voltage battery releases energy to the high-voltage battery, thereby improving the safety of the system, and reducing the risk of battery overcharging by avoiding the reverse charging phenomenon, thereby reducing the incidence of safety accidents.

[0043] The present invention can achieve rapid balancing: through the rapid switching characteristics and precise control of the power MOS tube, rapid balancing between battery cells is achieved, thereby improving the balancing efficiency.

[0044] The present invention can perform precise control: the ADC module is used to monitor the battery voltage in real time, the PID module is used to accurately calculate the voltage difference, and a control signal is output, thereby achieving precise control of the battery balancing process; precise control of the charging process helps to reduce heat loss caused by current fluctuations and maintain the temperature stability of the battery system.

[0045] The single cell of the present invention is the main body of energy storage and release. Through active balancing, the service life of the battery pack can be effectively extended to prevent performance degradation or damage caused by voltage imbalance between battery cells.

[0046] The above description is only a preferred embodiment of the present invention, and does not limit the patent scope of the present invention. All equivalent structural changes made by using the contents of the present invention specification and drawings under the inventive concept of the present invention, or directly / indirectly applied in other related technical fields are included in the patent protection scope of the present invention.

Claims

1. A capacitor type battery active balancing circuit, characterized in that: include: Multiple single cells, power MOS tube circuits, energy storage circuits, and control loops; The control loop includes an ADC module, a PID module, a constant current controller and a power MOS tube driving module; the corresponding end of the ADC module is electrically connected to a plurality of single cells and a corresponding end of the PID module respectively; the corresponding end of the PID module is connected to a corresponding end of the power MOS tube driving module via a constant current controller; the corresponding end of the power MOS tube driving module is electrically connected to a corresponding end of a power MOS tube circuit, and the corresponding end of the power MOS tube circuit is also connected to a plurality of single cells and a corresponding end of an energy storage circuit respectively.

2. The active equalization circuit for capacitor type batteries according to claim 1, characterized in that: The plurality of single cells include single cells BAT1 and single cells BAT2; the ADC module includes ADC1 and ADC2, wherein ADC1 is used to collect the voltage VBAT1 of the single cell BAT1, and ADC2 is used to collect the voltage VBAT2 of the single cell BAT2.

3. The active equalization circuit for capacitor type batteries according to claim 2, characterized in that: The PID module is used to calculate the absolute value ΔV=|VBAT2 - VBAT1| of the voltage difference between the single battery BAT1 and the single battery BAT2, and output a control signal to adjust the power balancing process.

4. The active equalization circuit for capacitor type batteries according to claim 3, characterized in that: The constant current controller adjusts the switching frequency f of the power MOS tube circuit according to the output signal of the PID module. SW Or charging time T D , to control the rate at which the energy storage circuit transfers energy to the low-voltage battery cells.

5. The active equalization circuit for capacitor type batteries according to claim 4, characterized in that: The power MOS tube driving module is used to drive the MOS tube circuit to control the energy transfer between the single battery BAT1 and the single battery BAT2.

6. The active equalization circuit for a capacitor type battery according to claim 5, characterized in that: The power MOS tube circuit comprises a MOS tube (Q1), a MOS tube (Q2), a MOS tube (Q3), and a MOS tube (Q4); The source electrode of the MOS tube (Q1) is electrically connected to the positive electrode of the single battery BAT2, the drain electrode of the MOS tube (Q1) is electrically connected to the first end of the energy storage circuit and the drain electrode of the MOS tube (Q2), and the gate electrode of the MOS tube (Q1) is electrically connected to the corresponding end of the power MOS tube driving module; The source electrode of the MOS tube (Q2) is electrically connected to the negative electrode of the single battery BAT2, the positive electrode of the single battery BAT1, and the source electrode of the MOS tube (Q3), respectively, and the gate electrode of the MOS tube (Q2) is electrically connected to the corresponding end of the power MOS tube driving module; The drain of the MOS tube (Q3) is electrically connected to the second end of the energy storage circuit and the drain of the MOS tube (Q4), respectively, and the gate of the MOS tube (Q3) is electrically connected to the corresponding end of the power MOS tube driving module; The source electrode of the MOS tube (Q4) is electrically connected to the negative electrode of the single battery BAT1 and is grounded, and the gate electrode of the MOS tube (Q4) is electrically connected to the corresponding end of the power MOS tube driving module.

7. The active equalization circuit for capacitor type batteries according to claim 6, characterized in that: The energy storage circuit comprises an energy storage capacitor (C1) for temporarily storing energy from a high-voltage battery cell and transferring the energy to a low-voltage battery cell when needed.

8. A capacitor type battery active balancing method, used in the capacitor type battery active balancing circuit according to any one of claims 1 to 7, characterized in that: This includes any of the following methods: Method 1: Step A1: Turn on the MOS tube (Q1) and the MOS tube (Q3), so that the single battery BAT2 is connected in parallel with the energy storage capacitor (C1), and the voltage of the energy storage capacitor (C1) is VBAT2; Step A2: Turn on the MOS tube (Q2) and the MOS tube (Q3) to connect the single battery BAT1 and the energy storage capacitor (C1) in parallel, and the voltage of the energy storage capacitor (C1) is VBAT1; Step A3, calculate the charge Q carried by the energy storage capacitor (C1) in one balancing cycle, Q = |VBAT2 - VBAT1|* (C1) = ΔV *(C1); Step A4: Calculate the average balancing current I AVG , I AVG = Q * f SW = ΔV * (C1) * f SW , and control f SW To maintain I AVG constant, where f SW is the switching frequency of the power MOS tube; Method 2: Step S1: measuring voltages VBAT1 and VBAT2 of a single battery BAT1 and a single battery BAT2; Step S2: According to the size of VBAT1 and VBAT2, the MOS tube circuit is controlled to charge the energy storage circuit; Step S3: Calculate the average balancing current I AVG , and control the charging time T D To maintain I AVG Constant.

9. The active equalization method for capacitor type batteries according to claim 8, characterized in that: In step S2, when VBAT2>VBAT1, the gate (G1) of the power MOS tube (Q1) is controlled so that the MOS tube (Q1) uses the current I H The capacitor (C1) is charged and the power MOS tube (Q3) is fully turned on; When VBAT2 < VBAT1, the gate (G4) of the power MOS tube (Q4) is controlled so that the MOS tube (Q4) uses the current I H The capacitor (C1) is charged and the power MOS tube (Q2) is fully turned on.

10. The active equalization method for capacitor type batteries according to claim 8, characterized in that: In step S3, the formula for the average balancing current is I AVG = Q / T = I H * T D / T,T D = I AVG * T / I H , where Q is the charge transferred by the energy storage capacitor (C1), I H is the charging current of the capacitor, T D is the charging time of the capacitor, and T is the switching period.

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