Power battery control circuit for multi-battery pack dynamic equalization management

Abstract

The utility model discloses a power battery control circuit for multi-battery pack dynamic equalization management. The power battery control circuit comprises a single battery voltage difference detection module for detecting the voltage of a plurality of single batteries and calculating the voltage difference of each group; the transfer module comprises a switching circuit for selecting the single battery with the highest energy and the single battery with the lowest energy and a charging and discharging circuit for preferentially charging the voltage of the single battery with the highest energy into the voltage of the single battery with the lowest energy; according to the utility model, the switching circuit of the single batteries and the charging and discharging circuit which preferentially charges the voltage of the single battery with the highest energy into the voltage of the single battery with the lowest energy are arranged, so that after one-time energy transfer, the single batteries are allowed to work within a voltage difference threshold range, and the battery pack does not carry out finer energy balancing action any more; compared with a traditional equalization mode in which all single batteries participate in charging and discharging, the mode can reduce energy conversion times, improve equalization efficiency and reduce energy loss in the equalization process.

Description

Technical Field

[0001] This utility model relates to the field of power battery technology, specifically a power battery control circuit for dynamic balance management of multiple battery packs. Background Technology

[0002] Battery inconsistency refers to the phenomenon where battery parameters such as capacity, state of charge (SOC), internal resistance, and voltage vary due to internal differences or different external usage conditions. Over time, this inconsistency increases. When there are inconsistencies in capacity between cells within a battery cluster, the overall usable capacity of the battery system decreases, and inaccurate SOC estimations can lead to abrupt changes at the end of charge and discharge cycles. Battery balancing utilizes power electronics technology to maintain the voltage deviation of individual lithium-ion battery cells or the battery pack within a predetermined range. This ensures that each individual cell remains in the same state during normal use, preventing abnormalities such as overcharging and over-discharging.

[0003] Battery management systems (BMS) are a crucial core technology in fields such as electric vehicles, energy storage systems, and drones. Currently, dynamic balancing management of multiple battery packs is broadly divided into two types: passive balancing and active balancing. The former has a simple structure but low energy utilization, so active balancing is currently more commonly used to balance energy.

[0004] A search revealed a lithium-ion power battery charge-discharge active balancing circuit in patent application publication number CN105656142B. This circuit comprises two parts: an active charge-discharge balancing circuit between individual cells based on a supercapacitor, and an active charge-discharge balancing circuit between the battery module, individual cells, and an external power source. This balancing circuit uses a supercapacitor intermediate to balance individual cells. During balancing, multiple individual cells need to be discharged and charged. While it achieves the balancing effect, it is relatively energy-intensive. Utility Model Content

[0005] The purpose of this invention is to provide a power battery control circuit for dynamic equalization management of multiple battery packs. It reduces energy consumption by prioritizing charging the cell with the largest energy to the cell with the lowest energy and then re-comparing whether the voltage difference between the individual cells is within a threshold. This replaces the method of having all individual cells participate in charging and discharging.

[0006] To achieve the above objectives, this utility model provides the following technical solution: a power battery control circuit for dynamic equalization management of multiple battery packs, including a single-cell voltage difference detection module that detects the voltage of multiple individual cells and calculates the voltage difference of each pack;

[0007] A comparison module, which compares the battery voltage difference obtained by the single cell voltage difference detection module with a preset threshold, controls the inductor to absorb energy from the high-voltage cell and release the inductor energy to the low-voltage cell after the comparison module detects that the single cell voltage difference exceeds the threshold.

[0008] The transfer module includes a switching circuit that selects the highest-energy single cell and the lowest-energy single cell, and a charging and discharging circuit that prioritizes charging the voltage of the highest-energy single cell into the voltage of the lowest-energy single cell.

[0009] Preferably, the single cell differential pressure detection module includes chip U1 and chip U2. A resistor R1 is connected to the IN1 terminal of chip U1, a resistor R2 is connected to one end of the resistor R1, a resistor R3 is connected to one end of the resistor R2, and the IN2 terminal of chip U1 is connected to both the resistor R2 and the resistor R3.

[0010] A resistor R4 is connected to the IN1 terminal of the chip U2. A resistor R5 is connected to one end of the resistor R4. One end of the resistor R5 is grounded. One end of the resistor R4 is connected to the resistor R3. The VCC terminal of the chip U1 is connected to the VCC terminal of the chip U2.

[0011] The VCC terminal of chip U1 is connected to the VCC terminal of chip U2, and a switch S and a capacitor C2 are connected to it. Both chip U1 and chip U2 are CN303 models.

[0012] Preferably, the comparison module includes an operational amplifier U11 and an optocoupler U14. The non-inverting input terminal of the operational amplifier U11 is connected to a resistor R85, one end of the resistor R85 is connected to a resistor R75, the inverting input terminal of the operational amplifier U11 is connected to resistors R69 and R70, the output of the operational amplifier U11 and one end of the resistor R69 are both connected to the power supply VCC, and the output terminal of the operational amplifier U11 is connected to the first pin of the optocoupler U14.

[0013] Preferably, the comparison module further includes an operational amplifier U12, the circuit connection of the non-inverting input terminal, the inverting input terminal and the output terminal of the operational amplifier U12 is the same as the circuit connection of the operational amplifier U11;

[0014] The optocoupler U14 is a tlp521gb-s model, and the operational amplifiers U11 and U12 are both LM393 models.

[0015] Preferably, the switching circuit includes a MOSFET Q4 and a transistor Q1. The gate (G) of the MOSFET Q4 is connected to the collector of the transistor Q1. The emitter of the transistor Q1 is connected to a switch KEY1. The collector of the transistor Q1 has an output port. The gate of the MOSFET Q4 is connected to diodes D1 and D2 in sequence. The switch KEY1 is connected between diodes D1 and D2. The anode of diode D2 has an input port.

[0016] Preferably, the charging and discharging circuit includes an ETA6003Q3Q chip. Pin 14 of the ETA6003Q3Q chip is configured as the positive terminal of the battery. Pins 12 and 11 of the ETA6003Q3Q chip are respectively connected to resistors R15 and R16. Pin 9 of the ETA6003Q3Q chip is connected to resistor R12. One end of resistor R12 is connected to a light-emitting diode (LED1). The positive terminal of LED1 is connected to pin 15 of the ETA6003Q3Q chip. Pin 10 of the ETA6003Q3Q chip is connected to capacitor C1. Pins 1 and 2 of the ETA6003Q3Q chip are respectively connected to capacitors C7 and C8. Pin 3 of the ETA6003Q3Q chip is connected to inductor L1.

[0017] Compared with the prior art, the beneficial effects of this utility model are:

[0018] This invention, by setting up a switching circuit for individual cells and a charging / discharging circuit that prioritizes charging the highest-energy individual cell to the lowest-energy individual cell, can perform directional energy transfer by prioritizing the highest and lowest-energy cells. After one energy transfer, the individual cells are allowed to operate within the voltage difference threshold range, and the battery pack will no longer perform more refined energy balancing. Compared with the traditional balancing method where all individual cells participate in charging and discharging, this method can reduce the number of energy conversions, improve balancing efficiency, and reduce energy loss during the balancing process. Attached Figure Description

[0019] Figure 1 This is a system block diagram of this utility model;

[0020] Figure 2 This is the circuit diagram of the practical single-cell battery differential pressure detection module;

[0021] Figure 3 This is the circuit diagram of this practical comparison module;

[0022] Figure 4 This is the circuit diagram of this practical switching circuit;

[0023] Figure 5This is the circuit diagram of a practical charging and discharging circuit. Detailed Implementation

[0024] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0025] Please see Figure 1-5 This utility model provides a technical solution: a power battery control circuit for dynamic equalization management of multiple battery packs, including a single-cell voltage difference detection module that detects the voltage of multiple individual cells and calculates the voltage difference of each pack.

[0026] A comparison module, which compares the battery voltage difference obtained by the single cell voltage difference detection module with a preset threshold, controls the inductor to absorb energy from the high-voltage cell and release the inductor energy to the low-voltage cell after the comparison module detects that the single cell voltage difference exceeds the threshold.

[0027] The transfer module includes a switching circuit that selects the highest-energy single cell and the lowest-energy single cell, and a charging and discharging circuit that prioritizes charging the voltage of the highest-energy single cell into the voltage of the lowest-energy single cell.

[0028] By measuring the energy of each individual cell and comparing the voltage difference between the lowest energy cells, no balancing action is performed when the voltage difference is within a threshold. When the voltage difference is outside the threshold, the switching circuit will select to turn on the charging circuit of the lowest energy cell and the discharging circuit of the highest energy cell to transfer energy.

[0029] The single cell differential pressure detection module includes chip U1 and chip U2. A resistor R1 is connected to the IN1 terminal of chip U1, a resistor R2 is connected to one end of the resistor R1, a resistor R3 is connected to one end of the resistor R2, and the IN2 terminal of chip U1 is connected to the resistor R2 and the resistor R3 respectively.

[0030] A resistor R4 is connected to the IN1 terminal of the chip U2. A resistor R5 is connected to one end of the resistor R4. One end of the resistor R5 is grounded. One end of the resistor R4 is connected to the resistor R3. The VCC terminal of the chip U1 is connected to the VCC terminal of the chip U2.

[0031] The VCC terminal of chip U1 is connected to the VCC terminal of chip U2, and a switch S and a capacitor C2 are connected to it. Both chip U1 and chip U2 are CN303 models.

[0032] Resistors R1, R2, R3, R4, and R5 form a resistor voltage divider network to achieve a precise voltage sampling ratio and ensure the accuracy of differential voltage detection. The integrated capacitor C2 for filtering and switch S for power supply control can improve the stability of the detection circuit and reduce static power consumption.

[0033] The comparison module includes an operational amplifier U11 and an optocoupler U14. The non-inverting input of the operational amplifier U11 is connected to a resistor R85, and one end of the resistor R85 is connected to a resistor R75. The inverting input of the operational amplifier U11 is connected to resistors R69 and R70. The output of the operational amplifier U11 and one end of the resistor R69 are both connected to the power supply VCC. The output of the operational amplifier U11 is connected to the first pin of the optocoupler U14.

[0034] The combination of a voltage divider network with resistors R85 and R75 and feedback resistors R69 and R70 provides adjustable threshold setting capability.

[0035] The comparison module also includes an operational amplifier U12, the circuit connections of the non-inverting input terminal, the inverting input terminal, and the output terminal of the operational amplifier U12 are the same as the circuit connections of the operational amplifier U11.

[0036] Differential comparison is achieved by using dual operational amplifiers of LM393. The redundant design of dual comparators can enhance system reliability, avoid imbalance caused by single-point failure, and improve the accuracy of threshold determination. Electrical isolation is achieved by using optocoupler TLP521GB-S to prevent interference from high-voltage battery pack to control circuit.

[0037] The optocoupler U14 is a tlp521gb-s model, and the operational amplifiers U11 and U12 are both LM393 models.

[0038] The switching circuit includes a MOSFET Q4 and a transistor Q1. The gate (G) of the MOSFET Q4 is connected to the collector of the transistor Q1. The emitter of the transistor Q1 is connected to a switch KEY1. The collector of the transistor Q1 has an output port. The gate of the MOSFET Q4 is connected to diodes D1 and D2 in sequence. The switch KEY1 is connected between diodes D1 and D2. The anode of diode D2 has an input port.

[0039] High-speed, low-loss switching is achieved by combining MOSFET Q4 and transistor Q1, with an on-resistance of only 4mΩ. Series protection of diodes D1 and D2 ensures precise switching timing and prevents false triggering. Mechanical switch KEY1 is connected in parallel with electronic switch to provide a hardware-level emergency operation interface.

[0040] The charging and discharging circuit includes an ETA6003Q3Q chip. Pin 14 of the ETA6003Q3Q chip is configured as the positive terminal of the battery. Pins 12 and 11 of the ETA6003Q3Q chip are respectively connected to resistors R15 and R16. Pin 9 of the ETA6003Q3Q chip is connected to resistor R12. One end of resistor R12 is connected to a light-emitting diode (LED1). The positive terminal of LED1 is connected to pin 15 of the ETA6003Q3Q chip. Pin 10 of the ETA6003Q3Q chip is connected to capacitor C1. Pins 1 and 2 of the ETA6003Q3Q chip are respectively connected to capacitors C7 and C8. Pin 3 of the ETA6003Q3Q chip is connected to inductor L1.

[0041] Inductor L1, along with capacitors C7 and C8, forms a π-type filter, which reduces the impact of ripple on battery life. The ETA6003Q3Q chip enables a bidirectional Buck-Boost topology, improving charging and discharging efficiency. A comparison module, based on the individual cell voltage difference detection module, compares the battery voltage difference with a preset threshold. If the comparison module detects that the individual cell voltage difference exceeds the threshold, it controls a transfer module that absorbs energy from the high-voltage cell and releases the inductor energy to the low-voltage cell. This transfer module includes a switching circuit for selecting the highest-energy and lowest-energy individual cells, and a charging / discharging circuit.

[0042] In use, the individual battery voltage difference detection module measures the voltage of each individual battery through the high-precision voltage comparator inside the dual-channel voltage detection integrated circuits U1 and U2, and compares the lowest voltage with the lowest voltage to obtain the voltage difference. When the voltage difference is within the threshold, the circuit does not perform equalization. When the voltage difference exceeds the threshold, the switching circuit connected in the charging and discharging circuit of each individual battery prioritizes the charging circuit of the lowest energy individual battery and the discharging circuit of the highest energy individual battery. This allows the lowest energy individual battery to be charged. During charging, the charging process is controlled by the ETA6003Q3Q chip, including three stages: pre-charging, constant current, and constant voltage. The battery voltage detection module inside the ETA6003Q3Q chip monitors the battery voltage in real time to ensure that the charging process conforms to the voltage characteristics of lithium batteries. At the same time, the external battery protection circuit connected to the ETA6003Q3Q chip completes the discharge of the highest energy individual battery, realizing energy transfer. During the transfer process, the LM393 dual operational amplifier cyclically compares the battery pack voltage difference with the threshold. When the overall voltage difference of the battery pack is within the threshold, the energy transfer stops.

[0043] Although embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the present invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A multi-battery pack dynamic balancing management power battery control circuit, characterized in that: The single battery voltage difference detection module includes detecting voltage of multiple single batteries and calculating voltage difference of each group of single batteries; The comparison module compares the battery voltage difference with a preset threshold value according to the single battery voltage difference detection module, and the transfer module controls the inductor to absorb energy from the high-voltage single battery and release the energy to the low-voltage single battery according to the comparison module detecting that the single voltage difference exceeds the threshold value. The transfer module includes a switch circuit for selecting the single battery with the highest energy and the single battery with the lowest energy and a charge-discharge circuit for preferentially charging the single battery with the highest energy into the single battery with the lowest energy.

2. The power battery control circuit of claim 1, wherein: The single battery voltage difference detection module includes a chip U1 and a chip U2, an IN1 terminal of the chip U1 is connected with a resistor R1, one end of the resistor R1 is connected with a resistor R2, one end of the resistor R2 is connected with a resistor R3, and an IN2 terminal of the chip U1 is connected with the resistor R2 and the resistor R3 respectively; An IN1 terminal of the chip U2 is connected with a resistor R4, one end of the resistor R4 is connected with a resistor R5, one end of the resistor R5 is grounded, one end of the resistor R4 is connected with the resistor R3, and a VCC terminal of the chip U1 is connected with a VCC terminal of the chip U2; After the VCC terminal of the chip U1 is connected with the VCC terminal of the chip U2, a switch S and a capacitor C2 are connected, and the chip U1 and the chip U2 are both of CN303 type.

3. The power battery control circuit of claim 2, wherein: The comparison module includes an operational amplifier U11 and an optical coupler U14, a same-phase input terminal of the operational amplifier U11 is connected with a resistor R85, one end of the resistor R85 is connected with a resistor R75, an opposite-phase input terminal of the operational amplifier U11 is connected with resistors R69 and R70, the output of the operational amplifier U11 and one end of the resistor R69 are both connected with a power supply VCC, and the output terminal of the operational amplifier U11 is connected with a first pin of the optical coupler U14.

4. The power battery control circuit of claim 3, wherein: The comparison module further includes an operational amplifier U12, the circuit connection of the same-phase input terminal, the opposite-phase input terminal and the output terminal of the operational amplifier U12 is the same as that of the operational amplifier U11. The optical coupler U14 is of tlp521gb-s type, and the operational amplifier U11 and the operational amplifier U12 are both of LM393 type.

5. The power battery control circuit of claim 4, wherein: The switch circuit includes a MOS tube Q4 and a triode Q1, the G pole of the MOS tube Q4 is connected with the collector of the triode Q1, the emitter of the triode Q1 is connected with a switch KEY1, the collector of the triode Q1 is provided with an output port, the G pole of the MOS tube Q4 is connected with a diode D1 and a diode D2 in sequence, the switch KEY1 is connected between the diode D1 and the diode D2, and the positive pole of the diode D2 is provided with an input port.

6. The power battery control circuit of claim 5, wherein: The charging and discharging circuit comprises an ETA6003Q3Q chip, a 14th pin of the ETA6003Q3Q chip is arranged as a battery positive access end, a 12th pin and an 11th pin of the ETA6003Q3Q chip are respectively connected with a resistor R15 and a resistor R16, a 9th pin of the ETA6003Q3Q chip is connected with a resistor R12, one end of the resistor R12 is connected with a light emitting diode LED1, a positive electrode of the light emitting diode LED1 is connected with a 15th pin of the ETA6003Q3Q chip, a 10th pin of the ETA6003Q3Q chip is connected with a capacitor C1, a 1st pin and a 2nd pin of the ETA6003Q3Q chip are respectively connected with a capacitor C7 and a capacitor C8, and a 3rd pin of the ETA6003Q3Q chip is connected with an inductor L1.

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