A battery charging and discharging control system

Abstract

The present invention relates to the field of battery charging, and in particular to a battery charging and discharging control system, comprising a controller and a discharge circuit and a charging circuit respectively connected to the controller, wherein one end of the discharge circuit is connected to the negative electrode of the battery, and the other end is connected in series with a load and then connected to the positive electrode of the battery to form a discharge circuit, and one end of the charging circuit is connected to the negative electrode of the battery, and the other end is connected to the negative electrode of a charging module, and the positive electrode of the charging module is connected to the positive electrode of the battery to form a charging circuit. The beneficial effects of the present invention are as follows: the discharge circuit and the charging circuit are two circuits, and the discharge circuit can be disconnected during the charging process. Since the load cannot be used, the problem of prohibiting the battery from discharging to the load during the charging process is solved, and the safety of lithium battery electric vehicles during the charging process is ensured.

Description

Technical Field

[0001] The invention relates to the field of battery charging, and in particular to a battery charging and discharging control system. Background Art

[0002] Existing battery charge and discharge control circuits such as Figure 1 As shown, two MOS tubes Q1 and Q2 are directly connected. When the charger is charging, the charging MOS tube Q1 and the discharging MOS tube Q2 are turned on at the same time to charge the battery. The current flows from the charger to the positive electrode of the battery, and then flows from the negative end of the battery through the charging MOS tube Q1 and the discharging MOS tube Q2, and finally flows back to the negative end of the charger. Since the discharging MOS tube Q2 is also turned on, the battery can also be discharged. The discharge current flows through the load and flows back to the discharging MOS tube Q2 and the charging MOS tube Q1, and finally flows back to the negative end of the battery, so the load can also operate. Therefore, the electric vehicle can still operate while charging, and it is easy to use the load during misoperation charging, thereby causing unnecessary danger.

[0003] In addition, although the existing battery charge and discharge control circuit can turn off the discharge MOS tube Q2 during the charging process, the load current cannot pass through the discharge MOS tube Q2, so the load cannot be used at this time, but the charging current at this time will flow through the body diode of the discharge MOS tube to generate a very high temperature rise - the greater the current, the higher the temperature rise, which will result in thermal breakdown of the discharge MOS tube Q2 and eventually cause the circuit board to fail, so the logic control method can only turn on the discharge MOS tube Q2 during the charging process. Summary of the invention

[0004] In order to solve the above problems, the present invention proposes a battery charging and discharging control system.

[0005] A battery charge and discharge control system, comprising a controller and a discharge circuit and a charging circuit respectively connected to the controller, wherein one end of the discharge circuit is connected to the negative electrode of the battery, and the other end is connected in series with a load and then connected to the positive electrode of the battery to form a discharge circuit, and one end of the charging circuit is connected to the negative electrode of the battery, and the other end is connected to the negative electrode of a charging module, and the positive electrode of the charging module is connected to the positive electrode of the battery to form a charging circuit;

[0006] During the battery charging process, the controller controls the discharge circuit to be disconnected and the charging circuit to be turned on;

[0007] During the battery discharge process, the controller controls the discharge circuit to be turned on and the charging circuit to be turned off.

[0008] Preferably, the charging circuit includes a charging MOS tube Q4, a G pole of the charging MOS tube Q4 is connected to the controller, an S pole is connected to the negative pole of the charging module, a D pole is connected to the negative pole of the battery, and a positive pole of the charging module is connected to the positive pole of the battery.

[0009] Preferably, the discharge circuit includes a discharge MOS tube Q3, a G pole of the discharge MOS tube Q3 is connected to the controller, an S pole is connected to one end of the load, a D pole is connected to the negative pole of the battery, and the other end of the load is connected to the positive pole of the battery.

[0010] Preferably, it also includes a voltage detection circuit connected to both ends of the battery, the controller is connected to the voltage detection circuit to obtain a voltage signal, and controls the discharge circuit and the charging circuit according to the voltage signal to realize charging or discharging of the battery.

[0011] Preferably, it also includes a digital logic controller connected to the voltage detection circuit and the controller, and a drive circuit connected to the digital logic controller, wherein the drive circuit is connected to the discharge circuit and the charging circuit.

[0012] Preferably, the input end of the digital logic controller is connected to the controller and the voltage detection circuit to obtain a control signal and a voltage signal, and the control signal and the voltage signal are converted into digital signals and then output to the drive circuit in two ways, one digital signal controls the charging circuit, and the other digital signal controls the discharging circuit.

[0013] Preferably, the digital logic controller includes a first AND gate circuit, a second AND gate circuit, a first OR gate circuit, a second OR gate circuit, a first NAND gate circuit, a second NAND gate circuit and a NAND gate circuit, wherein the first input end of the first AND gate circuit is connected to the detection circuit, and the second input end is connected to the controller, the first input end of the first OR gate circuit is connected to the output end of the first AND gate circuit, and the second input end is connected to the controller, the first input end of the first NAND gate circuit is connected to the output end of the first OR gate circuit, and the second input end is connected to the output end of the NAND gate circuit, the output end of the first NAND gate circuit is connected to the drive circuit, the input end of the NAND gate circuit is connected to the controller, the first input end of the second AND gate circuit is connected to the detection circuit, and the second input end is connected to the controller, the first input end of the second OR gate circuit is connected to the output end of the second AND gate circuit, and the second input end is connected to the controller, the first input end of the second NAND gate circuit is connected to the output end of the second OR gate circuit, and the second input end is connected to the output end of the NAND gate circuit, and the output end of the second NAND gate circuit is connected to the drive circuit.

[0014] Preferably, the driving circuit includes a driving chip U1, transistors Q5, Q6, Q7, Q8, Q9, Q10, resistors R1, R2, R3, R4, R5, R6, R7, R8, R9, R10, R11, R12, R13, R14, R15, R16, the base of the transistor Q9 is connected to an output terminal Y1 of a digital logic controller, the emitter is connected to a power supply terminal, the collector is connected to one end of a resistor R12, and the resistor R15 is connected between the base and the emitter of the transistor Q9. The base of the transistor Q7 is connected to the other end of the resistor R12, the collector is connected to one end of the resistor R9, the resistor R11 is connected between the base and the emitter of the transistor Q7, the emitter of the transistor Q5 is connected to the power supply end, the base is connected to the other end of the resistor R9, the collector is connected to one end of the resistor R5, the resistor R7 is connected between the base and the emitter of the transistor Q5, the other end of the resistor R5 is connected to the first input end of the driving chip U1 and one end of the resistor R3, and the other end of the resistor R3 is grounded;

[0015] The base of the transistor Q10 is connected to an output terminal Y2 of the digital logic controller, the emitter is connected to the power supply terminal, the collector is connected to one end of the resistor R14, the resistor R16 is connected between the base and the emitter of the transistor Q10, the base of the transistor Q8 is connected to the other end of the resistor R14, the collector is connected to one end of the resistor R10, the resistor R13 is connected between the base and the emitter of the transistor Q8, the emitter of the transistor Q6 is connected to the power supply terminal, the base is connected to the other end of the resistor R10, the collector is connected to one end of the resistor R6, the resistor R8 is connected between the base and the emitter of the transistor Q6, the other end of the resistor R6 is connected to the second input terminal of the driving chip U1 and one end of the resistor R4, the other end of the resistor R4 is grounded, the first output terminal of the driving chip U1 is connected to one end of the resistor R1, the other end of the resistor R1 is connected to the charging circuit, the second output terminal of the driving chip U1 is connected to one end of the resistor R2, and the other end of the resistor R2 is connected to the charging circuit.

[0016] Preferably, it also includes a power chip and a voltage conversion circuit connected to the power chip and the voltage detection circuit, wherein the voltage conversion circuit converts the output voltage signal of the power chip into a reference voltage signal and outputs the reference voltage signal to the voltage detection circuit.

[0017] Preferably, the voltage conversion circuit includes a voltage conversion chip U2 connected to a power supply chip and a voltage detection circuit.

[0018] Beneficial effects of the present invention:

[0019] 1. The discharge circuit and the charging circuit are two circuits. The discharge circuit can be disconnected during the charging process. Since the load cannot be used, the problem of prohibiting the battery from discharging to the load during the charging process is solved, ensuring the safety of lithium battery electric vehicles during the charging process.

[0020] 2. Isolating the charging circuit from the discharging circuit can also solve the problem of the discharging circuit being disconnected and the temperature rising of the discharging circuit.

[0021] 3. The digital logic controller consists of the control signal input composed of the controller and the voltage detection circuit output signal. The control chip is started by pulse mode, which greatly reduces the abnormal startup or shutdown of the charging and discharging MOS tube due to software logic abnormalities, making the control method more flexible and changeable, with more feedback mechanisms and isolation from the drive, making the entire control method more reasonable, the safety performance more reliable, and preventing misjudgment caused by accidental jitter. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments.

[0023] Figure 1 It is a structural schematic diagram of the prior art of the present invention;

[0024] Figure 2 It is a structural schematic diagram of a battery charging and discharging control system according to an embodiment of the present invention;

[0025] Figure 3 It is a circuit schematic diagram of a discharge circuit and a charging circuit in a battery charge and discharge control system according to an embodiment of the present invention;

[0026] Figure 4 It is a structural schematic diagram of a voltage detection circuit in a battery charging and discharging control system according to an embodiment of the present invention;

[0027] Figure 5 It is a structural schematic diagram of a digital logic controller and a drive circuit in a battery charging and discharging control system according to an embodiment of the present invention;

[0028] Figure 6 It is a logic diagram of a digital logic controller in a battery charging and discharging control system according to an embodiment of the present invention;

[0029] Figure 7 It is a structural schematic diagram of a driving circuit in a battery charging and discharging control system according to an embodiment of the present invention;

[0030] Figure 8 It is a structural schematic diagram of a power chip and a voltage conversion circuit in a battery charging and discharging control system according to an embodiment of the present invention;

[0031] Fig. 9The present invention is a circuit diagram of a voltage conversion circuit in a battery charge and discharge control system according to an embodiment of the present invention. DETAILED DESCRIPTION

[0032] The technical solution of the present invention is further described below in conjunction with the accompanying drawings, but the present invention is not limited to these embodiments.

[0033] The present invention proposes a battery charging and discharging control system, such as Figure 2 As shown, it includes a controller and a discharge circuit and a charging circuit respectively connected to the controller, wherein one end of the discharge circuit is connected to the negative electrode of the battery, and the other end is connected in series with a load and then connected to the positive electrode of the battery to form a discharge circuit, one end of the charging circuit is connected to the negative electrode of the battery, and the other end is connected to the negative electrode of the charging module, and the positive electrode of the charging module is connected to the positive electrode of the battery to form a charging circuit; during the battery charging process, the controller controls the discharge circuit to be disconnected and the charging circuit to be turned on; during the battery discharging process, the controller controls the discharge circuit to be turned on and the charging circuit to be disconnected.

[0034] In this embodiment, the discharge circuit and the charging circuit are two loops. The discharge circuit can be disconnected during the charging process. Since the load cannot be used, the problem of prohibiting the battery from discharging to the load during the charging process is solved, thereby ensuring the safety of the lithium battery electric vehicle during the charging process.

[0035] Isolating the charging circuit from the discharging circuit can also solve the problem of the discharging circuit being disconnected and the temperature rising of the discharging circuit.

[0036] like Figure 3 As shown, the charging circuit includes a charging MOS tube Q4, the G pole of the charging MOS tube Q4 is connected to the controller, the S pole is connected to the negative pole of the charging module, the D pole is connected to the negative pole of the battery, and the positive pole of the charging module is connected to the positive pole of the battery. The discharging circuit includes a discharging MOS tube Q3, the G pole of the discharging MOS tube Q3 is connected to the controller, the S pole is connected to one end of the load, the D pole is connected to the negative pole of the battery, and the other end of the load is connected to the positive pole of the battery.

[0037] During the battery charging process, the controller controls the discharge MOS tube Q3 to be turned off and the charging MOS tube Q4 to be turned on, so as to realize battery charging; during the battery discharging process, the controller controls the discharge MOS tube Q3 to be turned on and the charging MOS tube Q4 to be turned off, so as to realize battery discharging to the load.

[0038] In one embodiment, if Figure 4 As shown, the system also includes a voltage detection circuit connected to both ends of the battery. The controller is connected to the voltage detection circuit to obtain a voltage signal, and controls the discharge circuit and the charging circuit according to the voltage signal to realize charging or discharging of the battery.

[0039] The controller obtains the voltage signal. When the voltage is less than the set threshold, the charging circuit is controlled to be turned on and the discharging circuit is turned off to achieve charging. When the voltage is greater than the set threshold, the discharging circuit is controlled to be turned on and the charging circuit is turned off to achieve discharging. Since the voltage detection circuit is an existing circuit, the circuit structure is not described in detail.

[0040] Considering that the existing circuit control generally uses two IO ports of the MCU to drive the shutdown of the transistor or MOS tube, and then directly controls the shutdown of the charging and discharging MOS tube, the protection level is insufficient, and abnormal switching is prone to occur when the MCU has software logic confusion or interference. The two MOS tubes also have the problem of inconsistent shutdown delay, which may cause abnormal situations.

[0041] To solve the above technical problems, in one embodiment, Figure 5 As shown, the system further includes a digital logic controller connected to the voltage detection circuit and the controller and a drive circuit connected to the digital logic controller, wherein the drive circuit is connected to the discharge circuit and the charging circuit.

[0042] The digital logic controller consists of the control signal input composed of the controller and the voltage detection circuit output signal. The control chip is started by pulse mode, which greatly reduces the abnormal startup or shutdown of the charging and discharging MOS tube due to software logic abnormalities, making the control method more flexible and changeable, with more feedback mechanisms and isolation from the drive, making the entire control method more reasonable, the safety performance more reliable, and preventing misjudgment caused by unexpected jitter.

[0043] The digital logic controller uses the MAX17601ASASS3 chip produced by Maxim to drive the charging and discharging MOS tubes. The normal working power consumption of this chip is 1mA, the delay is 12nS, and it has the function of dual input and dual output.

[0044] like Figure 6As shown, the digital logic controller includes a first AND gate circuit, a second AND gate circuit, a first OR gate circuit, a second OR gate circuit, a first NAND gate circuit, a second NAND gate circuit and a NAND gate circuit, wherein the first input end of the first AND gate circuit is connected to the detection circuit, and the second input end is connected to the controller, the first input end of the first OR gate circuit is connected to the output end of the first AND gate circuit, and the second input end is connected to the controller, the first input end of the first NAND gate circuit is connected to the output end of the first OR gate circuit, and the second input end is connected to the output end of the NAND gate circuit, the output end of the first NAND gate circuit is connected to the drive circuit, the input end of the NAND gate circuit is connected to the controller, the first input end of the second AND gate circuit is connected to the detection circuit, and the second input end is connected to the controller, the first input end of the second OR gate circuit is connected to the output end of the second AND gate circuit, and the second input end is connected to the controller, the first input end of the second NAND gate circuit is connected to the output end of the second OR gate circuit, and the second input end is connected to the output end of the NAND gate circuit, and the output end of the second NAND gate circuit is connected to the drive circuit.

[0045] The digital logic controller turns off the charging MOS tube during battery charging protection to prevent the battery from overcharging; turns off the discharging MOS tube during discharging protection to prevent the battery from over-discharging; and can turn off the discharging MOS tube during charging, so that there is no discharge during charging. The logic expression of the digital logic controller is: Y1=(A')'·(B+CD)', Y1 is the logic control output terminal, and the input signal A is the controller that controls the two inputs of the driver chip through the non-gate output at the same time; it can meet the need to turn off the charging and discharging MOS tubes at the same time. When set to 1, the output is high level, and the charging and discharging MOS tubes are turned off at the same time (the output high level MOS tube is turned off). B is the input terminal of the OR gate, and the input signal C is the input terminal of the AND gate, which can be controlled by the controller. During normal operation, B is set to 0, and C is set to 1 or 0 to control the shutdown or conduction of the discharge MOS tube. D is the voltage feedback signal. When the D level changes from high to low, the output signal Y1 is set to 1, and the discharge MOS tube is turned off; Y2 controls the charging MOS tube signal, and the analysis is the same as above; in summary, the shutdown of the charging and discharging MOS tubes can be controlled flexibly, quickly and efficiently, and the application scenarios are diversified. Based on this solution, different software control logics can obtain different control methods.

[0046] like Figure 7As shown, the driving circuit includes a driving chip U1, transistors Q5, Q6, Q7, Q8, Q9, Q10, resistors R1, R2, R3, R4, R5, R6, R7, R8, R9, R10, R11, R12, R13, R14, R15, R16, the base of the transistor Q9 is connected to an output terminal Y1 of the digital logic controller, the emitter is connected to the power supply terminal, the collector is connected to one end of the resistor R12, and the resistor R15 is connected between the base and the emitter of the transistor Q9. The base of the transistor Q7 is connected to the other end of the resistor R12, the collector is connected to one end of the resistor R9, the resistor R11 is connected between the base and emitter of the transistor Q7, the emitter of the transistor Q5 is connected to the power supply end, the base is connected to the other end of the resistor R9, the collector is connected to one end of the resistor R5, the resistor R7 is connected between the base and emitter of the transistor Q5, the other end of the resistor R5 is connected to the first input end of the driving chip U1 and one end of the resistor R3, the the other end is grounded; the base of the transistor Q10 is connected to an output terminal Y2 of the digital logic controller, the emitter is connected to the power supply end, the collector is connected to one end of the resistor R14, the resistor R16 is connected between the base and the emitter of the transistor Q10, the base of the transistor Q8 is connected to the other end of the resistor R14, the collector is connected to one end of the resistor R10, the resistor R13 is connected between the base and the emitter of the transistor Q8, the emitter of the transistor Q6 is connected to the power supply end, the base is connected to the other end of the resistor R10, the collector is connected to one end of the resistor R6, the resistor R8 is connected between the base and the emitter of the transistor Q6, the other end of the resistor R6 is connected to the second input end of the driving chip U1 and one end of the resistor R4, the other end of the resistor R4 is grounded, the first output end of the driving chip U1 is connected to one end of the resistor R1, the other end of the resistor R1 is connected to the charging circuit, the second output end of the driving chip U1 is connected to one end of the resistor R2, and the other end of the resistor R2 is connected to the charging circuit.

[0047] The logic control output terminal Y2 (discharge MOS control terminal) outputs a low level to control a transistor Q10 to turn on, and then controls the transistor Q8 to turn on, so that the transistor Q6 is turned on, and the INB signal (driving voltage 12V) directly enters the input terminal of the MOS tube driver chip U1. The circuit composed of these three transistors can convert digital signals into a large voltage input drive mode, so that the signal at the input terminal of the control driver chip U1 reaches the turn-on threshold, and outputs this corresponding signal to the MOS tube G pole to drive the charging MOS tube to turn off. The control principle of the logic control output terminal Y1 is the same as above and will not be repeated.

[0048] like Figure 8As shown, the system also includes a power chip and a voltage conversion circuit connected to the power chip and the voltage detection circuit. The voltage conversion circuit converts the output voltage signal of the power chip into a reference voltage signal and outputs it to the voltage detection circuit.

[0049] Specifically, Fig. 9 As shown, the voltage conversion circuit includes a voltage conversion chip U2 connected to the power chip and the voltage detection circuit, and also includes resistors R17, R18, capacitor C3, inductor L1 connected to the voltage conversion chip U2, and capacitors C1, C2 connected to the inductor L1. The voltage conversion circuit converts the output voltage of the power chip into the voltage required by the system.

[0050] Those skilled in the art to which the present invention relates may make various modifications or additions to the specific embodiments described or replace them in a similar manner, but they will not deviate from the spirit of the present invention or exceed the scope defined by the attached claims.

Claims

1. A battery charge and discharge control system, characterized in that: It includes a controller and a discharge circuit and a charging circuit respectively connected to the controller, wherein one end of the discharge circuit is connected to the negative electrode of the battery, and the other end is connected in series with a load and then connected to the positive electrode of the battery to form a discharge circuit; one end of the charging circuit is connected to the negative electrode of the battery, and the other end is connected to the negative electrode of the charging module, and the positive electrode of the charging module is connected to the positive electrode of the battery to form a charging circuit; During the battery charging process, the controller controls the discharge circuit to be disconnected and the charging circuit to be turned on; During the battery discharge process, the controller controls the discharge circuit to be turned on and the charging circuit to be turned off; It also includes a voltage detection circuit connected to both ends of the battery, the controller is connected to the voltage detection circuit to obtain a voltage signal, and controls the discharge circuit and the charging circuit according to the voltage signal to realize charging or discharging of the battery; It also includes a digital logic controller connected to the voltage detection circuit and the controller, and a drive circuit connected to the digital logic controller, wherein the drive circuit is connected to the discharge circuit and the charging circuit; The driving circuit includes a driving chip U1, transistors Q5, Q6, Q7, Q8, Q9, Q10, resistors R1, R2, R3, R4, R5, R6, R7, R8, R9, R10, R11, R12, R13, R14, R15, R16, the base of the transistor Q9 is connected to an output terminal Y1 of a digital logic controller, the emitter is connected to a power supply terminal, the collector is connected to one end of a resistor R12, the resistor R15 is connected between the base and the emitter of the transistor Q9, the The base of the transistor Q7 is connected to the other end of the resistor R12, the collector is connected to one end of the resistor R9, the resistor R11 is connected between the base and the emitter of the transistor Q7, the emitter of the transistor Q5 is connected to the power supply end, the base is connected to the other end of the resistor R9, the collector is connected to one end of the resistor R5, the resistor R7 is connected between the base and the emitter of the transistor Q5, the other end of the resistor R5 is connected to the first input end of the driving chip U1 and one end of the resistor R3, and the other end of the resistor R3 is grounded; The base of the transistor Q10 is connected to an output terminal Y2 of the digital logic controller, the emitter is connected to the power supply terminal, the collector is connected to one end of the resistor R14, the resistor R16 is connected between the base and the emitter of the transistor Q10, the base of the transistor Q8 is connected to the other end of the resistor R14, the collector is connected to one end of the resistor R10, the resistor R13 is connected between the base and the emitter of the transistor Q8, the emitter of the transistor Q6 is connected to the power supply terminal, the base is connected to the other end of the resistor R10, the collector is connected to one end of the resistor R6, the resistor R8 is connected between the base and the emitter of the transistor Q6, the other end of the resistor R6 is connected to the second input terminal of the driving chip U1 and one end of the resistor R4, the other end of the resistor R4 is grounded, the first output terminal of the driving chip U1 is connected to one end of the resistor R1, the other end of the resistor R1 is connected to the charging circuit, the second output terminal of the driving chip U1 is connected to one end of the resistor R2, the other end of the resistor R2 is connected to the charging circuit; It also includes a power chip and a voltage conversion circuit connected to the power chip and the voltage detection circuit. The voltage conversion circuit converts the output voltage signal of the power chip into a reference voltage signal and outputs it to the voltage detection circuit.

2. A battery charge and discharge control system according to claim 1, characterized in that: The charging circuit includes a charging MOS tube Q4, a G pole of the charging MOS tube Q4 is connected to the controller, an S pole is connected to the negative pole of the charging module, a D pole is connected to the negative pole of the battery, and a positive pole of the charging module is connected to the positive pole of the battery.

3. A battery charge and discharge control system according to claim 1, characterized in that: The discharge circuit comprises a discharge MOS tube Q3, wherein the G pole of the discharge MOS tube Q3 is connected to the controller, the S pole is connected to one end of the load, the D pole is connected to the negative pole of the battery, and the other end of the load is connected to the positive pole of the battery.

4. A battery charge and discharge control system according to claim 1, characterized in that: The input end of the digital logic controller is connected to the controller and the voltage detection circuit to obtain a control signal and a voltage signal, and the control signal and the voltage signal are converted into digital signals and then output to the drive circuit in two ways, one digital signal controls the charging circuit, and the other digital signal controls the discharging circuit.

5. A battery charge and discharge control system according to claim 4, characterized in that: The digital logic controller includes a first AND gate circuit, a second AND gate circuit, a first OR gate circuit, a second OR gate circuit, a first NAND gate circuit, a second NAND gate circuit and a NAND gate circuit. The first input end of the first AND gate circuit is connected to the detection circuit, and the second input end is connected to the controller. The first input end of the first OR gate circuit is connected to the output end of the first AND gate circuit, and the second input end is connected to the controller. The first input end of the first NAND gate circuit is connected to the output end of the first OR gate circuit, and the second input end is connected to the output end of the NAND gate circuit. The output end of the first NAND gate circuit is connected to the drive circuit. The input end of the NAND gate circuit is connected to the controller. The first input end of the second AND gate circuit is connected to the detection circuit, and the second input end is connected to the controller. The first input end of the second OR gate circuit is connected to the output end of the second AND gate circuit, and the second input end is connected to the controller. The first input end of the second NAND gate circuit is connected to the output end of the second OR gate circuit, and the second input end is connected to the output end of the NAND gate circuit. The output end of the second NAND gate circuit is connected to the drive circuit.

6. A battery charge and discharge control system according to claim 1, characterized in that: The voltage conversion circuit includes a voltage conversion chip U2 connected to a power chip and a voltage detection circuit.

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