Charging and discharging control circuit for independently controlling battery and system thereof

Abstract

The invention discloses a charging and discharging control circuit for independently controlling a battery and a system thereof, and relates to the technical field of battery charging, the control circuit adopts an independent control mode to carry out closed-loop regulation on the charging current of a BAT, and the problems of aging difference, capacity fading and the like caused by consumption of the cycle index of the battery are avoided; the control efficiency can be optimized according to charging time constants of different battery parameters, the adaptation range can be expanded, the control circuit comprises a control unit, the control unit comprises a plurality of operational amplifiers, a plurality of resistors, a plurality of digital potentiometers, a field effect transistor and a phase inverter, and the in-phase end of an operational amplifier U1 in the operational amplifiers is connected with a third pin of the digital potentiometer U2 and one end of a resistor R3; the anti-phase end is connected with one end of the resistor R2 and one end of the resistor R5, and the output end is connected with one end of the resistor R4; the in-phase end of the operational amplifier U4 is connected with the Vin1 end, the anti-phase end of the operational amplifier U4 is connected with the fifth pin and the sixth pin of the digital potentiometer U3 and the third pin of the digital potentiometer U6, and the output end of the operational amplifier U4 is connected with the second pin of the digital potentiometer U3, the input end of the inverter U5 and the P1 end.

Description

Technical Field

[0001] The present invention relates to the technical field of battery charging, and particularly relates to a charge and discharge control circuit and system for independently controlling a battery. Background Art

[0002] In the high-voltage battery packs on the market, during the charging and discharging processes of lithium-ion batteries, problems such as overcharging, over-discharging, or overheating and safety hazards may be faced. As a result, when the lithium battery is used improperly, it may malfunction, and even cause the battery to heat up or explode. This is because the voltage difference between the individual batteries in the battery pack is too large, resulting in overcharging or over-discharging. To address this problem, the prior art uses an equalization method to ensure that the battery is within a safe voltage range. Among them, passive equalization is achieved by connecting a resistor in parallel to the battery cell with a higher voltage at the end of charging to dissipate the excess energy in the form of heat, making the voltages of the individual cells in the battery pack tend to be the same; while active equalization transfers the energy of the high-charge cells to the low-charge cells through energy storage components such as inductors, capacitors, or transformers to achieve the redistribution of energy within the battery pack. However, no matter which method is used, the voltage safety range is maintained by consuming the cycle times of the battery, which will reduce the expected life of the battery. And when a certain cell or group of cells reaches the full-charge state, it will also suffer greater capacity attenuation due to continuous discharging. This not only increases the aging difference among the batteries in the battery pack but also reduces the energy utilization efficiency of the entire battery system. Therefore, a charge and discharge control circuit and system for independently controlling a battery are proposed. Summary of the Invention

[0003] In view of the above technical problems, the object of the present invention is to provide a charge and discharge control circuit for independently controlling a battery, including a control unit. The control unit includes several operational amplifiers, several resistors, several digital potentiometers, field effect transistors, and inverters. The non-inverting input terminal of operational amplifier U1 among the several operational amplifiers is connected to the third pin of digital potentiometer U2 and one end of resistor R3, the inverting input terminal is connected to one end of resistor R2 and one end of resistor R5, and the output terminal is connected to one end of resistor R4; the non-inverting input terminal of operational amplifier U4 is connected to Vin1 terminal, the inverting input terminal is connected to the fifth pin, sixth pin of digital potentiometer U3, and the third pin of digital potentiometer U6, and the output terminal is connected to the second pin of digital potentiometer U3, the input terminal of inverter U5, and P1 terminal; the second pin of digital potentiometer U2 is connected to the output terminal of inverter U5 and the second pin of digital potentiometer U6, the seventh pin is connected to the seventh pin of digital potentiometer U3, the seventh pin of digital potentiometer U6, and P2 terminal, the eighth pin, the third pin of digital potentiometer U3, one end of resistor R1, the other end of resistor R2, and the other end of resistor R3 are connected to the power supply; the eighth pin of digital potentiometer U3 is connected to the eighth pin of digital potentiometer U6; the gate of field effect transistor Q1 is connected to the other end of resistor R4, the source is connected to the other end of resistor R1, the drain is connected to Port1 terminal, the drain of field effect transistor Q1 outputs a charging current, and then feeds back to battery BAT through a switching circuit; the fourth pin, fifth pin, sixth pin of digital potentiometer U2, the fourth pin of digital potentiometer U3, the fourth pin, fifth pin, sixth pin of digital potentiometer U6, and the other end of resistor R5 are grounded.

[0004] Further, the control unit further includes several operational amplifiers, several inverters, several field effect transistors, several triodes, several diodes, several resistors, an AND gate, and a solid state relay. The non-inverting input terminal of operational amplifier U8 among the several operational amplifiers is connected to the non-inverting input terminal of operational amplifier U9, the inverting input terminal is connected to the normally closed contact of solid state relay K1, the collector of triode Q3, the source of field effect transistor Q5, one end of resistor R8, and one end of resistor R14, and the output terminal is connected to the input terminal of inverter U11; the inverting input terminal of operational amplifier U9 is connected to the normally open contact of solid state relay K1, the source of field effect transistor Q4, the collector of triode Q6, one end of resistor R9, and one end of resistor R12, and the output terminal is connected to the input terminal of inverter U10; the first input terminal of AND gate U7 is connected to the output terminal of inverter U11 and the anode of diode D2, the second input terminal is connected to the output terminal of inverter U10 and the anode of diode D3, and the output terminal is connected to the seventh pin of digital potentiometer U6 through P2 terminal; the drain of field effect transistor Q4 is connected to the cathode of diode D3; the drain of field effect transistor Q5 is connected to the cathode of diode D2; the gate of field effect transistor Q4 is connected to the gate of field effect transistor Q5 and Vin2 terminal; one end of the coil of solid state relay K1 is connected to P1 terminal, and the other end of the coil is connected to the emitter of triode Q2; the base of triode Q2 is connected to one end of resistor R7; the common terminal of solid state relay K1, the other end of resistor R8, and the other end of resistor R9 are connected to the power supply; the collector of triode Q2, the emitter of triode Q3, the emitter of triode Q6, and the other end of resistor R7 are grounded.

[0005] Further, the control unit further includes a plurality of resistors. One end of resistor R6 among the plurality of resistors is connected to the seventh pin of digital potentiometer U2; one end of resistor R11 is connected to the second pin of digital potentiometer U2; the other end of resistor R6 and the other end of resistor R11 are grounded.

[0006] Further, the control unit further includes a diode. The anode of diode D1 is connected to the other end of the coil of solid-state relay K1, and the cathode is connected to terminal P1.

[0007] Further, resistor R3 is a variable resistor.

[0008] Further, the control unit further includes a plurality of resistors. One end of resistor R10 among the plurality of resistors is connected to one end of resistor R13 and the non-inverting input terminal of operational amplifier U8, and the other end is connected to the power supply; the other end of resistor R13 is grounded.

[0009] Further, the control unit further includes a resistor. One end of resistor R15 is connected to the gate of field effect transistor Q4, and the other end is grounded.

[0010] Further, an independent charge and discharge control system for a battery includes the independent charge and discharge control circuit for a battery according to any one of the above.

[0011] The beneficial effects of the present invention compared with the prior art are as follows: The present invention uses an independent control method to perform closed-loop regulation on the charging current of BAT, avoiding problems such as aging differences and capacity attenuation caused by consuming the cycle times of the battery; it can also optimize the control efficiency according to the charging time constants of different battery parameters, increasing the adaptation range. Description of the Drawings

[0012] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following will briefly introduce the drawings required in the prior art and the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0013] Figure 1 It is the circuit structure diagram provided by the present invention. Detailed Embodiments

[0014] In order to make the purpose and advantages of the present invention clearer, the following will specifically describe the present invention in combination with embodiments. It should be understood that the following text only describes one or several specific implementation manners of the present invention, and does not strictly limit the protection scope specifically claimed by the present invention.

[0015] The present invention discloses a charge and discharge control circuit for an independent control battery, including a control unit. The control unit includes several operational amplifiers, several resistors, several digital potentiometers, a field effect transistor, and an inverter. The non-inverting input terminal of operational amplifier U1 among the several operational amplifiers is connected to the third pin of digital potentiometer U2 and one end of resistor R3, the inverting input terminal is connected to one end of resistor R2 and one end of resistor R5, and the output terminal is connected to one end of resistor R4; the non-inverting input terminal of operational amplifier U4 is connected to Vin1 terminal, the inverting input terminal is connected to the fifth pin, the sixth pin of digital potentiometer U3, and the third pin of digital potentiometer U6, and the output terminal is connected to the second pin of digital potentiometer U3, the input terminal of inverter U5, and P1 terminal; the second pin of digital potentiometer U2 is connected to the output terminal of inverter U5 and the second pin of digital potentiometer U6, the seventh pin is connected to the seventh pin of digital potentiometer U3, the seventh pin of digital potentiometer U6, and P2 terminal, the eighth pin, the third pin of digital potentiometer U3, one end of resistor R1, the other end of resistor R2, and the other end of resistor R3 are connected to the power supply; the eighth pin of digital potentiometer U3 is connected to the eighth pin of digital potentiometer U6; the gate of field effect transistor Q1 is connected to the other end of resistor R4, the source is connected to the other end of resistor R1, the drain is connected to Port1 terminal, the drain of field effect transistor Q1 outputs a charging current, and is fed back to battery BAT through a switching circuit; the fourth pin, the fifth pin, the sixth pin of digital potentiometer U2, the fourth pin of digital potentiometer U3, the fourth pin, the fifth pin, the sixth pin of digital potentiometer U6, and the other end of resistor R5 are grounded.

[0016] Specifically, the control unit further includes several operational amplifiers, several inverters, several field effect transistors, several triodes, several diodes, several resistors, an AND gate, and a solid state relay. The non-inverting input terminal of operational amplifier U8 among the several operational amplifiers is connected to the non-inverting input terminal of operational amplifier U9, the inverting input terminal is connected to the normally closed contact of solid state relay K1, the collector of triode Q3, the source of field effect transistor Q5, one end of resistor R8, and one end of resistor R14, and the output terminal is connected to the input terminal of inverter U11; the inverting input terminal of operational amplifier U9 is connected to the normally open contact of solid state relay K1, the source of field effect transistor Q4, the collector of triode Q6, one end of resistor R9, and one end of resistor R12, and the output terminal is connected to the input terminal of inverter U10; the first input terminal of AND gate U7 is connected to the output terminal of inverter U11 and the anode of diode D2, the second input terminal is connected to the output terminal of inverter U10 and the anode of diode D3, and the output terminal is connected to the seventh pin of digital potentiometer U6 through P2 terminal; the drain of field effect transistor Q4 is connected to the cathode of diode D3; the drain of field effect transistor Q5 is connected to the cathode of diode D2; the gate of field effect transistor Q4 is connected to the gate of field effect transistor Q5 and Vin2 terminal; one end of the coil of solid state relay K1 is connected to P1 terminal, and the other end of the coil is connected to the emitter of triode Q2; the base of triode Q2 is connected to one end of resistor R7; the common terminal of solid state relay K1, the other end of resistor R8, and the other end of resistor R9 are connected to the power supply; the collector of triode Q2, the emitter of triode Q3, the emitter of triode Q6, and the other end of resistor R7 are grounded.

[0017] Specifically, the control unit further includes a plurality of resistors. One end of resistor R6 among the plurality of resistors is connected to the seventh pin of digital potentiometer U2; one end of resistor R11 is connected to the second pin of digital potentiometer U2; the other end of resistor R6 and the other end of resistor R11 are grounded.

[0018] Specifically, the control unit further includes a diode. The anode of diode D1 is connected to the other end of the coil of solid-state relay K1, and the cathode is connected to terminal P1.

[0019] Specifically, resistor R3 is a variable resistor.

[0020] Specifically, the control unit further includes a plurality of resistors. One end of resistor R10 among the plurality of resistors is connected to one end of resistor R13 and the non-inverting input terminal of operational amplifier U8, and the other end is connected to the power supply; the other end of resistor R13 is grounded.

[0021] Specifically, the control unit further includes a resistor. One end of resistor R15 is connected to the gate of field effect transistor Q4, and the other end is grounded.

[0022] Specifically, an independent charge and discharge control system for a battery includes the independent charge and discharge control circuit described in any one of the above.

[0023] In one embodiment, considering that the method of maintaining the voltage safety range by consuming the number of battery cycles will increase the battery aging difference and reduce the battery expected life, in the solution, each battery or battery pack BAT is first connected to the control unit through a switching circuit to control charging and discharging. The battery voltage is fed back to Vin1, and the control unit inputs different charging currents or discharging currents to the battery according to different Vin1. The signal of Vin1 in the control unit is first input to the non-inverting terminal of the operational amplifier U4. The inverting terminal of the operational amplifier U4 samples the series voltage between the fifth pin of the digital potentiometer U3 and the third pin of the digital potentiometer U6. After the circuit is powered on, the operational amplifier U4 compares and outputs a control signal. One path is fed back to the second pin of the digital potentiometer U3, and the other path is inverted by the inverter U5 and input to the second pins of the digital potentiometer U6 and the digital potentiometer U2. Assuming that the input signal voltage of Vin1 is greater than the series voltage between the fifth pin of the current digital potentiometer U3 and the third pin of the digital potentiometer U6, then one path of the output signal of the operational amplifier U4 is fed back to the second pin of U3, and the other path is inverted by U5 and input to the second pin of U6, controlling the cursor in the fifth pin of the digital potentiometer U3 to adjust towards the third pin direction, reducing the resistance value from the third pin to the fifth pin of the digital potentiometer U3. At the same time, the cursor in the fifth pin of the digital potentiometer U6 adjusts towards the sixth pin direction, increasing the resistance value from the third pin to the fifth pin of the digital potentiometer U6, converting the current Vin1 input voltage parameter into a resistance value parameter and feeding it back to the digital potentiometer U2. When the current Vin1 input signal voltage is less than the sampling voltage at the inverting terminal of the current operational amplifier U4, it is the opposite. When the digital potentiometer U3 and the digital potentiometer U6 are adjusted, the digital potentiometer U2 synchronizes the resistance value of the digital potentiometer U6. The third pin of the digital potentiometer U2 is connected to the resistor R3. The non-inverting terminal of the operational amplifier U1 samples the voltage at the connection end of the resistor R3 and the digital potentiometer U2. The inverting terminal of the operational amplifier U1 inputs a reference signal. The resistance value of the resistor R3 is used to control the initial charging current of the battery BAT. The resistor R3 in each unit is the same. The larger its resistance value, the greater the voltage drop after synchronization of the digital potentiometer U2, then the lower the driving voltage of the field effect transistor Q1 fed back by the operational amplifier U1 through the resistor R4, the lower the equivalent resistance value of the field effect transistor Q1, and the greater the charging current of BAT. As the voltage of BAT rises, Vin1 is gradually pulled up. After being regulated by the output of the operational amplifier U4, the digital potentiometer U6 enters a high impedance state. After the digital potentiometer U2 is synchronized, the input voltage of the non-inverting terminal of the operational amplifier U1 is pulled up until the field effect transistor Q1 is cut off, and BAT completes charging, ensuring that the battery will not be overcharged within the same charging time. Compared with dissipation and energy transfer, this method can actually reduce the charge and discharge cycles of the battery and prevent aging differences. The switching circuit is used to switch the connection between the battery BAT and the control circuit or the load. The attached drawings are not shown.

[0024] In one embodiment, the problem to be solved is the charging control efficiency problem caused by different battery parameters. Due to different battery parameters and different series connection numbers, the time constants of the charge and discharge processes are also different. When the charging current of the battery BAT is closed-loop regulated under the same parameters, when the charging current has been adjusted to the optimal value, the circuit will still continue to perform repeated calibration or there will be a calibration lag due to a low-speed clock. Therefore, based on the above solution, a charging solution with a detection function and a controllable interface is proposed to adapt to different products. Among them, Vin2 is the control interface, and a high-potential signal is input after power-on. During the detection process, when the operational amplifier U4 outputs a signal during the synchronization process of the digital potentiometer U2, it is fed back to the coil of the solid-state relay K1 through the P1 terminal. When the state of the output potential of the operational amplifier U4 changes, the auxiliary contact of the solid-state relay K1 is controlled to switch. The operational amplifiers U8 and U9 detect the output of the operational amplifier U4. Assuming that the voltage of the current Vin1 input signal is greater than the sampling voltage at the inverting terminal of the current operational amplifier U4, the signal at the output terminal of the operational amplifier U4 passes through the coil of the solid-state relay K1, the triode Q2, and the resistor R7 circuit, and the coil of the solid-state relay K1 is energized. The normally open contact of the solid-state relay K1 closes, and the normally closed contact of the solid-state relay K1 opens. One path of the power supply is fed back to the inverting terminal of the operational amplifier U9 through the normally open contact of the solid-state relay K1, and one path is input to the base of the triode Q3 through the resistor R12. When the base voltage of the triode Q3 is greater than the conduction voltage, after the triode Q3 conducts, it pulls down the potential at the connection end of the resistor R8 and the resistor R14, and the potential will be lower than the reference voltage potential set at the non-inverting terminals of the operational amplifiers U8 and U9. The reference voltage at the non-inverting terminal of the operational amplifier U8 is set by voltage division of the resistors R10 and R13 or directly supplied by the power supply. After the operational amplifier U8 compares, it outputs a high potential and feeds it back to the inverter U11 for inversion and waits for the subsequent response of the circuit. The diode D2 is connected in series between the output terminal of the inverter U11 and the drain of the field-effect transistor Q5 to eliminate the oscillation caused by backflow when the output state of the operational amplifier U4 changes. At the same time, the triode Q6 is lower than the conduction voltage, and the triode Q6 is cut off. At the same time, the low-potential output of the operational amplifier U9 is inverted by the inverter U10 and outputs a high-potential signal. One path is fed back to the AND gate U7, and the other path is fed back to the field-effect transistor Q4 through the diode D3. When Vin2 inputs a high potential, the field-effect transistor Q4 conducts and inputs an anchor voltage to the base of the triode Q6. After the above circuit is regulated, when the Vin1 signal is less than a regulated voltage level of the digital potentiometer U3 and the digital potentiometer U6 sampled at the inverting terminal of the current operational amplifier U4, the output of the operational amplifier U4 flips. After the coil of the solid-state relay K1 is disconnected, the normally closed contact closes again. One path of the power supply is fed back to the inverting terminal of the operational amplifier U8, and the other path is input to the base of the triode Q6 through the resistor R14. The triode Q6 conducts, and the voltage at the connection end of the resistor R9 and the resistor R12 is pulled down and the anchor voltage is loaded. The voltage potential is higher than the potential pulled down at the connection end of the resistor R8 and the resistor R14 when the operational amplifier U4 flips before the high-potential input of Vin2, and is greater than the reference voltage potential set by the resistors R10 and R13. When the power supply is fed back to the inverting terminal of the operational amplifier U8,The low potential output by the operational amplifier U8 is inverted by the inverter U11 and then input to the AND gate U7. The high potential signal output by the AND gate U7 is input to the seventh pins of the digital potentiometers U6, U3, and U2 through P2 to stop the adjustment. When rapidly adjusting, a resistor R15 can be connected in parallel to the gates of the field effect transistors Q5 and Q4 to discharge the gate charge and increase the response. Assume that when the current input signal voltage Vin1 is less than the sampling voltage at the inverting input terminal of the current operational amplifier U4, the low potential output by the operational amplifier U4 disconnects the coil of the solid state relay K1. The auxiliary contact of the solid state relay K1 is in the state shown in the attached drawing. The power signal passes through the resistor R14, the triode Q6, and the grounding circuit, and then the triode Q6 conducts. The voltage at the inverting input terminal of the operational amplifier U8 is greater than the voltage at the non-inverting input terminal. The low potential output of the operational amplifier U8 is inverted by the inverter U10 to output a high potential signal. One path is fed back to the AND gate U7, and the other path is fed back to the field effect transistor Q5 through the diode D2. When Vin2 inputs a high potential, the field effect transistor Q5 conducts and serves as an anchor voltage input to the base of the triode Q3. At the same time, the power signal is fed back to the base of the triode Q6. After the triode Q6 conducts, it pulls down the potential at the connection terminal of the pull-down resistor R12 and the resistor R9, and the potential voltage is lower than the reference voltage set at the non-inverting input terminals of the operational amplifiers U8 and U9, causing the operational amplifier U9 to output a high potential, which is inverted by the inverter U10 and waits for the subsequent circuit to respond. When the output of the operational amplifier U4 flips, during the process of making the triode Q3 conduct through the above circuit, the potential at the connection terminal of the resistor R8 and the resistor R14 is pulled down and the anchor potential of the field effect transistor Q5 is loaded. The potential voltage is higher than the pull-down potential at the connection terminal of the resistor R12 and the resistor R9 after the operational amplifier U4 flips before the high potential input of Vin2, and is greater than the reference voltage potential set by the resistors R10 and R13. At the same time, the high potential signal output by the AND gate U7 is input to the seventh pins of the digital potentiometers U6, U3, and U3 through P2 to stop the regulation of the current of BAT, avoiding repeated calibration. When Vin2 changes from high potential to low potential, the anchor potential is released. The digital potentiometers U6, U3, and U3 quickly adjust and calibrate the charging current of BAT under the high-speed clock signal clk to prevent hysteresis, and stop again after Vin2 inputs a high potential again and is detected by the above circuit. The diode D1 is used for the freewheeling of the coil of the solid state relay K1.

[0025] For those skilled in the art, it is obvious that the present invention is not limited to the details of the above exemplary embodiments, and without departing from the spirit or basic characteristics of the present invention, the present invention can be implemented in other specific forms. Therefore, from any point of view, the embodiments should be regarded as exemplary and non-limiting. The scope of the present invention is defined by the appended claims rather than the above description. Therefore, all changes falling within the meaning and scope of the equivalent elements of the claims are intended to be encompassed within the present invention. Any reference signs in the claims should not be regarded as limiting the claimed rights.

Claims

1. An independent charge and discharge control circuit for a battery, characterized in that, It includes a control unit, and the control unit includes several operational amplifiers, several resistors, several digital potentiometers, several field effect transistors and several inverters. The non-inverting input terminal of operational amplifier U1 among the several operational amplifiers is connected to the third pin of digital potentiometer U2 and one end of resistor R3, the inverting input terminal is connected to one end of resistor R2 and one end of resistor R5, and the output terminal is connected to one end of resistor R4; the non-inverting input terminal of operational amplifier U4 is connected to Vin1 terminal, the inverting input terminal is connected to the fifth pin, sixth pin of digital potentiometer U3 and the third pin of digital potentiometer U6, and the output terminal is connected to the second pin of digital potentiometer U3, the input terminal of inverter U5, and P1 terminal; the second pin of digital potentiometer U2 is connected to the output terminal of inverter U5 and the second pin of digital potentiometer U6, the seventh pin is connected to the seventh pin of digital potentiometer U3, the seventh pin of digital potentiometer U6, and P2 terminal, the eighth pin, the third pin of digital potentiometer U3, one end of resistor R1, the other end of resistor R2, and the other end of resistor R3 are connected to the power supply; the eighth pin of digital potentiometer U3 is connected to the eighth pin of digital potentiometer U6; the gate of field effect transistor Q1 is connected to the other end of resistor R4, the source is connected to the other end of resistor R1, the drain is connected to Port1 terminal, and the drain of field effect transistor Q1 outputs a charging current, which is then fed back to battery BAT through a switching circuit; the fourth pin, fifth pin, sixth pin of digital potentiometer U2, the fourth pin of digital potentiometer U3, the fourth pin, fifth pin, sixth pin of digital potentiometer U6, and the other end of resistor R5 are grounded.

2. The charge and discharge control circuit for independently controlling a battery according to claim 1, characterized in that The control unit further includes several triodes, several diodes, several resistors, an AND gate, and a solid state relay. The non-inverting input terminal of operational amplifier U8 among the several operational amplifiers is connected to the non-inverting input terminal of operational amplifier U9, the inverting input terminal is connected to the normally closed contact of solid state relay K1, the collector of triode Q3, the source of field effect transistor Q5, one end of resistor R8, and one end of resistor R14, and the output terminal is connected to the input terminal of inverter U11; the inverting input terminal of operational amplifier U9 is connected to the normally open contact of solid state relay K1, the source of field effect transistor Q4, the collector of triode Q6, one end of resistor R9, and one end of resistor R12, and the output terminal is connected to the input terminal of inverter U10; the first input terminal of AND gate U7 is connected to the output terminal of inverter U11 and the anode of diode D2, the second input terminal is connected to the output terminal of inverter U10 and the anode of diode D3, and the output terminal is connected through P2 terminal and the seventh pin of digital potentiometer U6; the drain of field effect transistor Q4 is connected to the cathode of diode D3; the drain of field effect transistor Q5 is connected to the cathode of diode D2; the gate of field effect transistor Q4 is connected to the gate of field effect transistor Q5 and Vin2 terminal; one end of the coil of solid state relay K1 is connected to P1 terminal, and the other end of the coil is connected to the emitter of triode Q2; the base of triode Q2 is connected to one end of resistor R7; the common terminal of solid state relay K1, the other end of resistor R8, and the other end of resistor R9 are connected to the power supply; the collector of triode Q2, the emitter of triode Q3, the emitter of triode Q6, and the other end of resistor R7 are grounded.

3. The charging and discharging control circuit for an independently controlled battery according to claim 1, characterized in that, One end of resistor R6 among the several resistors is connected to the seventh pin of digital potentiometer U2; one end of resistor R11 is connected to the second pin of digital potentiometer U2; the other end of resistor R6 and the other end of resistor R11 are grounded.

4. The charging and discharging control circuit for independently controlling a battery according to claim 2, characterized in that, The anode of diode D1 among the several diodes is connected to the other end of the coil of solid state relay K1, and the cathode is connected to P1 terminal.

5. The charging and discharging control circuit for independently controlling a battery according to claim 1, characterized in that, The resistor R3 is a variable resistor.

6. The independent charge and discharge control circuit for a battery according to claim 2, characterized in that, One end of the resistor R10 among the several resistors is connected to one end of the resistor R13 and the non-inverting input terminal of the operational amplifier U8, and the other end is connected to the power supply; the other end of the resistor R13 is grounded.

7. The charge and discharge control circuit for an independently controlled battery according to claim 2, characterized in that, One end of the resistor R15 among the several resistors is connected to the gate of the field effect transistor Q4, and the other end is grounded.

8. An independent charging and discharging control system for a battery, characterized in that, It includes the charge and discharge control circuit for an independently controlled battery according to any one of claims 1-7.

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