A battery management system

Abstract

This application is applicable to the field of battery management technology and provides a battery management system. In this battery management system, a switch unit for controlling the on / off of the charge and discharge circuit where the battery cell is located is set between the positive electrode of the battery cell and the positive charge and discharge port. In this way, when the switch control unit controls the switch unit to turn off according to the switch control signal output by the main control unit, thereby cutting off the charge and discharge circuit where the battery cell is located, it will not disconnect the ground of the battery management system from the ground of the system to which the battery cell is applied. As a result, when the battery management system performs a safety protection operation for the battery cell, the system to which the battery cell is applied can communicate normally, the battery management unit can read the voltage of the negative charge and discharge port corresponding to the negative electrode of the battery cell, the voltage of the signal of the negative charge and discharge port will not be elevated, and the switch tube in the charge and discharge circuit can be normally turned off when a fault occurs.

Description

Technical Field

[0001] This application belongs to the technical field of battery management, and particularly relates to a battery management system. Background Art

[0002] A Battery Management System (BMS) is a system used to monitor and manage batteries. It collects and calculates parameters such as the voltage, current, and temperature of the battery, and then controls the charging and discharging process of the battery to achieve battery protection and improve the comprehensive performance of the battery.

[0003] The BMS usually includes a switching transistor for controlling the on / off of the charging and discharging circuit where the battery is located. In the existing BMS, this switching transistor is usually arranged between the negative electrode of the battery and the negative charging and discharging port. In this way, when the BMS performs a safety protection operation for the battery and turns off this switching transistor, it will disconnect the ground of the BMS from the ground of the system to which the battery is applied, resulting in the inability of the system to which the battery is applied to communicate normally, the BMS being unable to read the voltage of the negative charging and discharging port corresponding to the negative electrode of the battery, the voltage of the signal of this negative charging and discharging port being elevated, and the switching transistor in the charging and discharging circuit being unable to be turned off when it fails, etc. Summary of the Invention

[0004] In view of this, the embodiments of this application provide a battery management system to solve the technical problems that in the existing BMS, when performing a safety protection operation for the battery, it will cause the system to which the battery is applied to be unable to communicate normally, the BMS being unable to read the voltage of the negative charging and discharging port corresponding to the negative electrode of the battery, the voltage of the signal of this negative charging and discharging port being elevated, and the switching transistor in the charging and discharging circuit being unable to be turned off when it fails.

[0005] The embodiments of this application provide a battery management system for connecting battery units, and the battery management system includes: a main control unit, a switch driving unit, a switch control unit, and a switch unit;

[0006] The main control unit is connected to the battery unit and the switch control unit, and is used to output a switch control signal to the switch control unit;

[0007] The switch driving unit is connected to the positive electrode of the battery unit and the switch control unit, and is used to provide a switch driving voltage for the switch control unit;

[0008] The switch control unit is connected to the switch unit, and is used to control the switch unit to conduct or turn off according to the switch control signal;

[0009] The switch unit is connected between the positive electrode of the battery unit and the positive charge and discharge port, and is used to connect the charge and discharge loop where the battery unit is located when it is turned on, or to cut off the charge and discharge loop where the battery unit is located when it is turned off.

[0010] Optionally, the battery management system further includes a self-excited oscillation unit connected to the switch driving unit;

[0011] The self-excited oscillation unit is used to provide a driving signal for the switch driving unit;

[0012] Correspondingly, the switch driving unit is specifically used to convert the reference voltage into the switch driving voltage under the drive of the driving signal.

[0013] Optionally, the battery management system further includes a reference voltage unit connected to the positive electrode of the battery unit and the switch driving unit;

[0014] The reference voltage unit is used to convert the voltage of the positive electrode of the battery unit into the reference voltage and provide the reference voltage for the switch driving unit.

[0015] Optionally, the switch unit includes: a first switch tube and a second switch tube;

[0016] The first conduction end of the first switch tube is connected to the positive electrode of the battery unit, the second conduction end of the first switch tube is connected to the first conduction end of the second switch tube, and the controlled end of the first switch tube is connected to the switch control unit; the first switch tube is used to connect or cut off the charging loop where the battery unit is located when the battery unit is charging;

[0017] The second conduction end of the second switch tube is connected to the positive charge and discharge port, and the controlled end of the second switch tube is connected to the switch control unit; the second switch tube is used to connect or cut off the discharge loop where the battery unit is located when the battery unit is discharging.

[0018] Optionally, the switch control unit includes: a first turn-off unit, a first turn-on unit, a second turn-off unit and a second turn-on unit;

[0019] The first control end of the first turn-off unit is connected to the positive electrode of the battery unit, and the second control end and the third control end of the first turn-off unit are both connected to the first turn-on unit; the controlled end of the first turn-on unit is connected to the charging control end of the main control unit, the driving end of the first turn-on unit is connected to the switch driving unit, the first control end of the first turn-on unit is connected to the positive electrode of the battery unit, and the second control end of the first turn-on unit is connected to the controlled end of the first switch tube;

[0020] The first control end of the second turn-off unit is connected to the second conduction end of the second switching tube, and both the second control end and the third control end of the second turn-off unit are connected to the second conduction unit; the controlled end of the second conduction unit is connected to the discharge control end of the main control unit, the driving end of the second conduction unit is connected to the switching driving unit, the first control end of the second conduction unit is connected to the second conduction end of the second switching tube, and the second control end of the second conduction unit is connected to the controlled end of the second switching tube.

[0021] Optionally, the first turn-off unit includes: a first resistor, an eighth resistor, a first diode, a fourth switching tube, a second resistor, a seventh resistor, a fifth switching tube, an eleventh resistor, and a twelfth resistor;

[0022] The first end of the first resistor, the first conduction end of the fourth switching tube, and the first end of the second resistor are commonly connected as the first control end of the first turn-off unit. The second end of the first resistor, the first end of the eighth resistor, and the controlled end of the fourth switching tube are commonly connected. The second end of the eighth resistor is connected to the anode of the first diode, and the cathode of the first diode is the second control end of the first turn-off unit. The second conduction end of the fourth switching tube, the first end of the seventh resistor, and the first end of the eleventh resistor are commonly connected. The second end of the seventh resistor is connected to the controlled end of the fifth switching tube. The first conduction end of the fifth switching tube is connected to the second end of the second resistor. The second conduction end of the fifth switching tube is connected to the first end of the twelfth resistor. The second end of the eleventh resistor and the second end of the twelfth resistor are commonly connected as the third control end of the first turn-off unit;

[0023] The first conduction unit includes: a fourth resistor, a third voltage regulator diode, a fifteenth resistor, a seventeenth resistor, an eighth switching tube, a nineteenth resistor, a twenty-second resistor, a fourth voltage regulator diode, a seventh switching tube, a twenty-first resistor, and a third diode;

[0024] The anode of the third zener diode and the first end of the fourth resistor are commonly connected as the first control end of the first conduction unit. The common connection point of the cathode of the third zener diode, the first end of the seventeenth resistor, the second end of the fourth resistor, and the second end of the fifteenth resistor is connected to the third control end of the first turn-off unit. The first end of the fifteenth resistor is the second control end of the first conduction unit. The second end of the seventeenth resistor is connected to the first conduction end of the eighth switching tube. The controlled end of the eighth switching tube, the second end of the nineteenth resistor, the anode of the fourth zener diode, and the first end of the twenty-second resistor are commonly connected. The second conduction end of the eighth switching tube, the cathode of the fourth zener diode, the second end of the twenty-second resistor, and the cathode of the third diode are commonly connected. The anode of the third diode is the drive end of the first conduction unit. The common connection point of the first end of the nineteenth resistor and the first conduction end of the seventh switching tube is connected to the second control end of the first turn-off unit. The controlled end of the seventh switching tube and the first end of the twenty-first resistor are commonly connected as the controlled end of the first conduction unit. The second conduction end of the seventh switching tube and the second end of the twenty-first resistor are both grounded.

[0025] Optionally, the second turn-off unit includes: a third resistor, a sixth resistor, a second diode, a third switching tube, a fifth resistor, a tenth resistor, a sixth switching tube, a thirteenth resistor, and a fourteenth resistor;

[0026] The first end of the third resistor, the first conduction end of the third switching tube, and the first end of the fifth resistor are commonly connected as the first control end of the second turn-off unit. The second end of the third resistor, the first end of the sixth resistor, and the controlled end of the third switching tube are commonly connected. The second end of the sixth resistor is connected to the anode of the second diode. The cathode of the second diode is the second control end of the second turn-off unit. The second conduction end of the third switching tube, the first end of the tenth resistor, and the first end of the thirteenth resistor are commonly connected. The second end of the tenth resistor is connected to the controlled end of the sixth switching tube. The first conduction end of the sixth switching tube is connected to the second end of the fifth resistor. The second conduction end of the sixth switching tube is connected to the first end of the fourteenth resistor. The second end of the thirteenth resistor and the second end of the fourteenth resistor are commonly connected as the third control end of the second turn-off unit;

[0027] The second conduction unit includes: a ninth resistor, a first zener diode, a sixteenth resistor, an eighteenth resistor, a ninth switching tube, a twentieth resistor, a twenty-third resistor, a second zener diode, a tenth switching tube, a twenty-fourth resistor, and a fourth diode;

[0028] The anode of the first voltage regulator diode and the first end of the ninth resistor are commonly connected to the first control end of the second conduction unit. The common connection point of the cathode of the first voltage regulator diode, the first end of the eighteenth resistor, the second end of the ninth resistor, and the second end of the sixteenth resistor is connected to the third control end of the second turn-off unit. The first end of the sixteenth resistor is connected to the controlled end of the second switching transistor. The second end of the eighteenth resistor is connected to the first conduction end of the ninth switching transistor. The controlled end of the ninth switching transistor, the first end of the twentieth resistor, the anode of the second voltage regulator diode, and the first end of the twenty-third resistor are commonly connected. The second conduction end of the ninth switching transistor, the cathode of the second voltage regulator diode, the second end of the twenty-third resistor, and the cathode of the fourth diode are commonly connected. The anode of the fourth diode is the drive end of the second conduction unit. The common connection point of the second end of the twentieth resistor and the first conduction end of the tenth switching transistor is connected to the second control end of the second turn-off unit. The controlled end of the tenth switching transistor and the first end of the twenty-fourth resistor are commonly connected as the controlled end of the second conduction unit. The second conduction end of the tenth switching transistor and the second end of the twenty-fourth resistor are both grounded.

[0029] Optionally, the switch driving unit includes: a fifth diode, a unidirectional conduction device, a second capacitor, a twenty-eighth resistor, a thirty-seventh resistor, a thirty-eighth resistor, an eleventh switching transistor, a twelfth switching transistor, a thirteenth switching transistor, a third capacitor, and a seventh capacitor;

[0030] The anode of the fifth diode is the first voltage input end of the switch driving unit. The cathode of the fifth diode is connected to the first end of the unidirectional conduction device. The third end of the unidirectional conduction device is connected to the first end of the third capacitor. The second end of the unidirectional conduction device and the second end of the seventh capacitor are commonly connected as the voltage output end of the switch driving unit. The first end of the second capacitor, the first end of the twenty-eighth resistor, and the first conduction end of the eleventh switching transistor are commonly connected as the reference voltage input end of the switch driving unit. The second end of the second capacitor is grounded. The second end of the twenty-eighth resistor, the first conduction end of the twelfth switching transistor, the controlled end of the eleventh switching transistor, and the controlled end of the thirteenth switching transistor are commonly connected. The first conduction end of the thirteenth switching transistor is connected to the second end of the third capacitor. The second end of the seventh capacitor, the second conduction end of the thirteenth switching transistor, the second conduction end of the twelfth switching transistor, and the second end of the thirty-eighth resistor are all grounded. The second end of the thirty-eighth resistor, the second end of the thirty-seventh resistor, and the controlled end of the twelfth switching transistor are commonly connected. The first end of the thirty-seventh resistor is the drive signal input end of the switch driving unit.

[0031] Optionally, the self-oscillation unit includes: a twenty-sixth resistor, a first capacitor, a twenty-seventh resistor, a seventh diode, a thirty-third resistor, a twelfth capacitor, a comparator, a thirty-ninth resistor, and a fortieth resistor;

[0032] The first end of the twenty-sixth resistor is used to receive the operating voltage of the self-oscillation unit. The second end of the twenty-sixth resistor and the first end of the first capacitor are commonly connected to the power supply terminal of the comparator. The second end of the first capacitor is grounded. The anode of the seventh diode, the second end of the thirty-third resistor, the output terminal of the comparator, and the second end of the fortieth resistor are commonly connected. The cathode of the seventh diode is connected to the second end of the twenty-seventh resistor. The first end of the twenty-seventh resistor, the first end of the thirty-third resistor, the first end of the twelfth capacitor, and the inverting input terminal of the comparator are commonly connected. The second end of the twelfth capacitor is grounded. The first end of the thirty-ninth resistor, the first end of the fortieth resistor, and the non-inverting input terminal of the comparator are commonly connected. The second end of the thirty-ninth resistor is connected to the reference voltage terminal of the comparator. The ground terminal of the comparator is grounded.

[0033] Optionally, the reference voltage unit includes: an eighth diode, a twenty-ninth resistor, a fourth capacitor, a thirtieth resistor, an eleventh capacitor, a thirty-fifth resistor, a power supply chip, a thirty-first resistor, a thirty-fourth resistor, a thirty-sixth resistor, a ninth capacitor, and a tenth capacitor;

[0034] The anode of the eighth diode is connected to the positive electrode of the battery unit. The cathode of the eighth diode is connected to the first end of the twenty-ninth resistor. The second end of the twenty-ninth resistor, the first end of the fourth capacitor, and the first end of the thirtieth resistor are commonly connected to the input pin of the power supply chip. The second end of the thirtieth resistor, the first end of the eleventh capacitor, and the first end of the thirty-fifth resistor are commonly connected to the enable pin of the power supply chip. The second end of the fourth capacitor, the second end of the eleventh capacitor, the second end of the thirty-fifth resistor, and the ground pin of the power supply chip are all grounded. The first end of the thirty-first resistor, the first end of the thirty-fourth resistor, the first end of the ninth capacitor, and the first end of the tenth capacitor are commonly connected to the output pin of the power supply chip. The second end of the thirty-first resistor is connected to the power supply status pin of the power supply chip. The second end of the thirty-fourth resistor and the first end of the thirty-sixth resistor are commonly connected to the feedback pin of the power supply chip. The second end of the thirty-sixth resistor, the second end of the ninth capacitor, and the second end of the tenth capacitor are all grounded.

[0035] Implementing the battery management system provided by the embodiments of the present application has the following beneficial effects:

[0036] The battery management system provided by the embodiments of the present application sets the switch unit for controlling the on / off of the charge and discharge circuit where the battery cell is located between the positive electrode of the battery cell and the positive charge and discharge port. In this way, when the switch control unit controls the switch unit to turn off according to the switch control signal output by the main control unit, thereby cutting off the charge and discharge circuit where the battery cell is located, it will not disconnect the ground of the battery management system from the ground of the system to which the battery cell is applied. As a result, when the battery management system performs a safety protection operation for the battery cell, the system to which the battery cell is applied can communicate normally, the battery management unit can read the voltage of the negative charge and discharge port corresponding to the negative electrode of the battery cell, the voltage of the signal of the negative charge and discharge port will not be elevated, and the switch tube in the charge and discharge circuit can be normally turned off when a fault occurs, that is, it solves the technical problems that the system to which the battery cell is applied cannot communicate normally, the battery management unit cannot read the voltage of the negative charge and discharge port corresponding to the negative electrode of the battery cell, the voltage of the signal of the negative charge and discharge port is elevated, and the switch tube in the charge and discharge circuit cannot be turned off when a fault occurs in the existing battery management system during the execution of the safety protection operation for the battery cell. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following will briefly introduce the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings in the following description are only some embodiments of the present application. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0038] Figure 1 FIG. is a schematic structural diagram of a battery management system provided by an embodiment of the present application;

[0039] Figure 2 FIG. is a schematic structure of a battery management system provided by another embodiment of the present application;

[0040] Figure 3 FIG. is a schematic circuit principle diagram of a battery management system provided by an embodiment of the present application. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0041] In the following description, specific details such as specific system structures and technologies are presented for the purpose of illustration rather than limitation, so as to thoroughly understand the embodiments of the present application. However, those skilled in the art should clearly understand that the present application can also be implemented in other embodiments without these specific details. In other cases, detailed descriptions of well-known systems, devices, circuits, and methods are omitted to avoid unnecessary details from interfering with the description of the present application.

[0042] It should be understood that in the description of the specification and the appended claims of this application, the terms "first", "second", "third", etc. are only used for distinguishing descriptions and should not be construed as indicating or implying relative importance. The terms "comprising", "including", "having" and their variants all mean "including but not limited to", unless otherwise specifically emphasized in other ways.

[0043] Please refer to Figure 1 , Figure 1 which is a schematic structural diagram of a battery management system provided by an embodiment of this application. As Figure 1 shown, the battery management system 100 can be connected to the battery unit 200 to monitor and manage the battery unit 200.

[0044] Among them, the battery unit 200 can be connected to a charging power source through a charge and discharge port to charge the battery unit 200 through the charging power source; the battery unit 200 can also be connected to a load through the charge and discharge port to supply power to the load. Among them, the charge and discharge port can include a positive charge and discharge port PACK+ and a negative charge and discharge port PACK-. In an embodiment of this application, the negative electrode of the battery unit 200 can be directly connected to the negative charge and discharge port PACK-, and the negative electrode of the battery unit 200 is grounded.

[0045] In specific applications, the battery unit 200 can be a battery pack formed by connecting multiple batteries in series, that is, the positive electrode of each battery in the battery pack is connected to the negative electrode of the previous battery, and the negative electrode of each battery is connected to the positive electrode of the next battery. Based on this, the positive electrode of the first battery in the battery pack is the positive electrode of the battery unit 200, and the negative electrode of the last battery in the battery pack is the negative electrode of the battery unit 200. By way of example and not limitation, the above battery can be a secondary battery, for example, it can be a lithium-ion battery.

[0046] In this embodiment, the battery management system 100 includes: a main control unit 11, a switch driving unit 12, a switch control unit 13, and a switch unit 14.

[0047] Specifically, the main control unit 11 is connected to the battery unit 200 and the switch control unit 13, and the main control unit 11 is used to output a switch control signal to the switch control unit 13.

[0048] In specific applications, by way of example and not limitation, the main control unit 11 can be connected to the positive electrode and the negative electrode of each battery in the battery unit 200 to monitor the states of the respective batteries. The main control unit 11 can output a switch control signal to the switch control unit 13 according to the states of the respective batteries.

[0049] Among them, the switch control signal is used to control the conduction or cutoff of the switch unit 14. In this embodiment, the switch control signal may include a conduction signal and a cutoff signal. The conduction signal is used to control the conduction of the switch unit 14, and the cutoff signal is used to control the cutoff of the switch unit 14.

[0050] It should be noted that the main control unit 11 can output the switch control signal to the switch control unit 13 when the battery unit 200 is charging, or can also output the switch control signal to the switch control unit 13 when the battery unit 200 is discharging. For example, when the battery unit 200 needs to be charged or discharged, the main control unit 11 can output a conduction signal to the switch control unit 13. When the main control unit 11 needs to perform a safety protection operation for the battery unit 200, the main control unit 11 can output a cutoff signal to the switch control unit 13.

[0051] In this embodiment, the circuit loop where the battery unit 200 is located when the battery unit 200 is charging is called the charging loop, and the circuit loop where the battery unit 200 is located when the battery unit 200 is discharging is called the discharging loop.

[0052] Specifically, the switch driving unit 12 is connected to the positive electrode of the battery unit 200 and the switch control unit 13, and the switch driving unit 12 is used to provide a switch driving voltage for the switch control unit 13.

[0053] In this embodiment, the switch driving unit 12 can, under the drive of a drive signal, convert a reference voltage into a switch driving voltage for driving the switch control unit 13 to work, and output the switch driving voltage to the switch driving unit 12.

[0054] As an example rather than a limitation, the above drive signal may be a pulse width modulation (PWM) signal. This PWM signal can be provided by a signal generator, or can be provided by a self-excited oscillation circuit, or can also be provided in other ways, which is not limited here. In a specific application, the above PWM signal may be a square wave signal.

[0055] As an example rather than a limitation, the above reference voltage can be provided by a reference voltage source.

[0056] Specifically, the switch control unit 13 is connected to the switch unit 14, and the switch control unit 13 is used to control the conduction or cutoff of the switch unit 14 according to the switch control signal output by the main control unit 11.

[0057] In this embodiment, under the drive of the switch driving voltage, when the switch control unit 13 receives the conduction signal output by the main control unit 11, it controls the switch unit 12 to conduct; when it receives the cutoff signal output by the main control unit 11, it controls the switch unit 12 to cutoff.

[0058] Specifically, the switch unit 14 is connected between the positive electrode of the battery unit 200 and the positive charge and discharge port PACK+. The switch unit 14 is used to connect the charge and discharge loop where the battery unit 200 is located when it is turned on, or to cut off the charge and discharge loop where the battery unit 200 is located when it is turned off.

[0059] In this embodiment, when the switch unit 14 is controlled to be turned on, the charge and discharge loop where the battery unit 200 is located is connected, and at this time, the battery unit 200 can be charged and discharged normally; when the switch unit 14 is controlled to be turned off, the charge and discharge loop where the battery unit 200 is located is cut off, and at this time, the battery unit 200 cannot be charged and discharged.

[0060] When the battery unit 200 is charging, if the switch unit 14 is controlled to be turned on, the charging loop where the battery unit 200 is located is connected, and at this time, the battery unit 200 can be charged normally; if the switch unit 14 is controlled to be turned off, the charging loop where the battery unit 200 is located is cut off, and at this time, the battery unit 200 cannot be charged.

[0061] When the battery unit 200 is discharging, if the switch unit 14 is controlled to be turned on, the discharge loop where the battery unit 200 is located is connected, and at this time, the battery unit 200 can discharge normally; if the switch unit 14 is controlled to be turned off, the discharge loop where the battery unit 200 is located is cut off, and at this time, the battery unit 200 cannot discharge.

[0062] As can be seen from the above, in the battery management system provided in this embodiment, by setting the switch unit for controlling the on-off of the charge and discharge loop where the battery unit is located between the positive electrode of the battery unit and the positive charge and discharge port, in this way, when the switch control unit controls the switch unit to be turned off according to the switch control signal output by the main control unit, thereby cutting off the charge and discharge loop where the battery unit is located, it will not disconnect the ground of the battery management system from the ground of the system to which the battery unit is applied. Thus, when the battery management system performs a safety protection operation for the battery unit, the system to which the battery unit is applied can communicate normally, the battery management unit can read the voltage of the negative charge and discharge port corresponding to the negative electrode of the battery unit, the voltage of the signal of the negative charge and discharge port will not be raised, and the switch tube in the charge and discharge loop can be turned off normally when a fault occurs, that is, it solves the technical problems that the system to which the battery unit is applied cannot communicate normally, the battery management unit cannot read the voltage of the negative charge and discharge port corresponding to the negative electrode of the battery unit, the voltage of the signal of the negative charge and discharge port is raised, and the switch tube in the charge and discharge loop cannot be turned off when a fault occurs in the existing battery management system.

[0063] Please refer to Figure 2 , Figure 2 which is a schematic structure of a battery management system provided in another embodiment of the present application, as Figure 2As shown, relative to Figure 1 the corresponding embodiment, the battery management system 100 in this embodiment further includes a self-excited oscillation unit 15 connected to the switch driving unit 12.

[0064] Specifically, the self-excited oscillation unit 15 is used to provide a driving signal for the switch driving unit 12.

[0065] Correspondingly, the switch driving unit 12 is specifically used to convert the reference voltage into a switch driving voltage under the driving of the above driving signal.

[0066] In this embodiment, the self-excited oscillation unit 15 can generate a PWM signal, and this PWM signal can be used as a driving signal for driving the switch driving unit 12 to work, so as to drive the switch driving unit 12 into a working state. After the switch driving unit 12 enters the working state, it performs voltage conversion on the reference voltage to obtain a switch driving voltage, and outputs this switch driving voltage to the switch control unit 13.

[0067] As an example rather than a limitation, the switch driving unit 12 can perform a boost process or a buck process on the reference voltage, and then obtain the switch driving voltage.

[0068] In another embodiment of the present application, the battery management system 100 further includes a reference voltage unit 16 connected to the positive electrode of the battery unit 200 and the switch driving unit 12.

[0069] Specifically, the reference voltage unit 16 is used to convert the voltage of the positive electrode of the battery unit 200 into a reference voltage, and provide this reference voltage for the switch driving unit 12.

[0070] In another embodiment of the present application, the switch unit 14 may include: a first switch tube Q1 and a second switch tube Q2. Among them, the first switch tube Q1 is used to control the on-off of the charging circuit where the battery unit 200 is located, and the second switch tube Q2 is used to control the on-off of the discharging circuit where the battery unit 200 is located.

[0071] Specifically, the first conducting end of the first switch tube Q1 is connected to the positive electrode of the battery unit 200, the second conducting end of the first switch tube Q1 is connected to the first conducting end of the second switch tube Q2, and the controlled end of the first switch tube Q1 is connected to the switch control unit 13; the first switch tube Q1 is used to connect or disconnect the charging circuit where the battery unit 200 is located when the battery unit 200 is charging.

[0072] Specifically, the second conducting end of the second switch tube Q2 is connected to the positive charge and discharge port PACK+, and the controlled end of the second switch tube Q2 is connected to the switch control unit 13; the second switch tube Q2 is used to connect or disconnect the discharging circuit where the battery unit 200 is located when the battery unit 200 is discharging.

[0073] Based on this, the switch control unit 13 may include: a first turn-off unit 131, a first turn-on unit 132, a second turn-off unit 133, and a second turn-on unit 134.

[0074] Specifically, the first control end of the first turn-off unit 131 is connected to the positive electrode of the battery unit 200, and both the second control end and the third control end of the first turn-off unit 131 are connected to the first turn-on unit 132; the controlled end of the first turn-on unit 132 is connected to the charging control end of the main control unit 11, the driving end of the first turn-on unit 132 is connected to the switch driving unit 12, the first control end of the first turn-on unit 132 is connected to the positive electrode of the battery unit 200, and the second control end of the first turn-on unit 132 is connected to the controlled end of the first switching tube Q1.

[0075] Specifically, the first control end of the second turn-off unit 133 is connected to the second conducting end of the second switching tube Q2, and both the second control end and the third control end of the second turn-off unit 133 are connected to the second turn-on unit 134; the controlled end of the second turn-on unit 134 is connected to the discharging control end of the main control unit 11, the driving end of the second turn-on unit 134 is connected to the switch driving unit 12, the first control end of the second turn-on unit 134 is connected to the second conducting end of the second switching tube Q2, and the second control end of the second turn-on unit 134 is connected to the controlled end of the second switching tube Q2.

[0076] In this embodiment, when the battery unit 200 is charging, the main control unit 11 may output a conducting signal to the first turn-on unit 132 through its charging control end. The first turn-on unit 132, under the drive of the switch driving voltage provided by the switch driving unit 12 and the control of this conducting signal, controls the first switching tube Q1 to conduct, thereby turning on the charging circuit where the battery unit 200 is located; the main control unit 11 may also output a turn-off signal to the first turn-on unit 132 through its charging control end. The first turn-on unit 132, under the drive of the switch driving voltage provided by the switch driving unit 12 and the control of this turn-off signal, enables the first turn-off unit 131 to control the first switching tube Q1 to turn off, thereby cutting off the charging circuit where the battery unit 200 is located.

[0077] When the battery cell 200 discharges, the main control unit 11 can output a conduction signal to the second conduction unit 134 through its discharge control terminal. Under the drive of the switching drive voltage provided by the switching drive unit 12 and the control of this conduction signal, the second conduction unit 134 controls the second switching transistor Q2 to conduct, thereby turning on the discharge circuit where the battery cell 200 is located; the main control unit 11 can also output a turn-off signal to the second conduction unit 134 through its discharge control terminal. Under the drive of the switching drive voltage provided by the switching drive unit 12 and the control of this turn-off signal, the second turn-off unit 133 causes the second switching transistor Q2 to turn off, thereby cutting off the discharge circuit where the battery cell 200 is located.

[0078] In another embodiment of the present application, the switching unit 14 may also include only one switching transistor, and this switching transistor is used to control the charge and discharge circuit where the battery cell 200 is located. Correspondingly, the switching control unit 13 may include only one conduction unit for controlling the conduction of this switching transistor and one turn-off unit for controlling the turn-off of this switching transistor.

[0079] In another embodiment of the present application, the battery management system 100 may further include an electrical parameter sensor 17. The electrical parameter sensor 17 may be connected between the negative electrode of the battery cell 200 and the negative charge and discharge port PACK-. The electrical parameter sensor 17 is used to collect the value of the preset electrical parameter of the battery cell 200 and send the collected value of the preset electrical parameter to the main control unit 11. By way of example and not limitation, the electrical parameter sensor 17 may be a resistor. Correspondingly, the preset electrical parameter may be the current in the charge and discharge circuit where the battery cell 200 is located, that is, the current value in the charge and discharge circuit where the battery cell 200 is located can be collected by connecting a resistor between the negative electrode of the battery cell 200 and the negative charge and discharge port PACK-.

[0080] Please refer to Figure 3 , Figure 3 which is a schematic circuit diagram of a battery management system provided by an embodiment of the present application. As Figure 3 shown, in this embodiment, the first turn-off unit 131 includes: a first resistor R1, an eighth resistor R8, a first diode D1, a fourth switching transistor Q4, a second resistor R2, a seventh resistor R7, a fifth switching transistor Q5, an eleventh resistor R11, and a twelfth resistor R12.

[0081] Specifically, the first end of the first resistor R1, the first conducting end of the fourth switching transistor Q4, and the first end of the second resistor R2 are commonly connected as the first control end of the first turn-off unit 131. The second end of the first resistor R1, the first end of the eighth resistor R8, and the controlled end of the fourth switching transistor Q4 are commonly connected. The second end of the eighth resistor R8 is connected to the anode of the first diode D1, and the cathode of the first diode D1 is the second control end of the first turn-off unit 131. The second conducting end of the fourth switching transistor Q4, the first end of the seventh resistor R7, and the first end of the eleventh resistor R11 are commonly connected. The second end of the seventh resistor R7 is connected to the controlled end of the fifth switching transistor Q5. The first conducting end of the fifth switching transistor Q5 is connected to the second end of the second resistor R2. The second conducting end of the fifth switching transistor Q5 is connected to the first end of the twelfth resistor R12. The second ends of the eleventh resistor R11 and the twelfth resistor R12 are commonly connected as the third control end of the first turn-off unit 131.

[0082] In another embodiment of the present application, the first conducting unit 132 includes: a fourth resistor R4, a third voltage regulator ZD3, a fifteenth resistor R15, a seventeenth resistor R17, an eighth switching transistor Q8, a nineteenth resistor R19, a twenty-second resistor R22, a fourth voltage regulator ZD4, a seventh switching transistor Q7, a twenty-first resistor R21, and a third diode D3.

[0083] Specifically, the anode of the third voltage regulator ZD3 and the first end of the fourth resistor R4 are commonly connected as the first control end of the first conducting unit 132. The common connection point of the cathode of the third voltage regulator ZD3, the first end of the seventeenth resistor R17, the second end of the fourth resistor R4, and the second end of the fifteenth resistor R15 is connected to the third control end of the first turn-off unit 131. The first end of the fifteenth resistor R15 is the second control end of the first conducting unit 132. The second end of the seventeenth resistor R17 is connected to the first conducting end of the eighth switching transistor Q8. The controlled end of the eighth switching transistor Q8, the second end of the nineteenth resistor R19, the anode of the fourth voltage regulator ZD4, and the first end of the twenty-second resistor R22 are commonly connected. The second conducting end of the eighth switching transistor Q8, the cathode of the fourth voltage regulator ZD4, the second end of the twenty-second resistor R22, and the cathode of the third diode D3 are commonly connected. The anode of the third diode D3 is the driving end of the first conducting unit 132. The common connection point of the first end of the nineteenth resistor R19 and the first conducting end of the seventh switching transistor Q7 is connected to the second control end of the first turn-off unit 131. The controlled end of the seventh switching transistor Q7 and the first end of the twenty-first resistor R21 are commonly connected as the controlled end of the first conducting unit. The second conducting end of the seventh switching transistor Q7 and the second end of the twenty-first resistor R21 are both grounded.

[0084] In yet another embodiment of the present application, the second turn-off unit 133 includes: a third resistor R3, a sixth resistor R6, a second diode D2, a third switching transistor Q3, a fifth resistor R5, a tenth resistor R10, a sixth switching transistor Q6, a thirteenth resistor R13, and a fourteenth resistor R14.

[0085] Specifically, the first end of the third resistor R3, the first conduction end of the third switching transistor Q3, and the first end of the fifth resistor R5 are commonly connected as the first control end of the second turn-off unit 133. The second end of the third resistor R3, the first end of the sixth resistor R6, and the controlled end of the third switching transistor Q3 are commonly connected. The second end of the sixth resistor R6 is connected to the anode of the second diode D2. The cathode of the second diode D2 is the second control end of the second turn-off unit. The second conduction end of the third switching transistor Q3, the first end of the tenth resistor R10, and the first end of the thirteenth resistor R13 are commonly connected. The second end of the tenth resistor R10 is connected to the controlled end of the sixth switching transistor Q6. The first conduction end of the sixth switching transistor Q6 is connected to the second end of the fifth resistor R5. The second conduction end of the sixth switching transistor Q6 is connected to the first end of the fourteenth resistor R14. The second end of the thirteenth resistor R13 and the second end of the fourteenth resistor R14 are commonly connected as the third control end of the second turn-off unit.

[0086] In yet another embodiment of the present application, the second conduction unit 134 includes: a ninth resistor R9, a first voltage-regulating diode ZD1, a sixteenth resistor R16, an eighteenth resistor R18, a ninth switching transistor Q9, a twentieth resistor R20, a twenty-third resistor R23, a second voltage-regulating diode ZD2, a tenth switching transistor Q10, a twenty-fourth resistor R24, and a fourth diode D4.

[0087] The anode of the first voltage regulator ZD1 and the first end of the ninth resistor R9 are commonly connected as the first control end of the second conduction unit 134. The common connection point of the cathode of the first voltage regulator ZD1, the first end of the eighteenth resistor R18, the second end of the ninth resistor R9, and the second end of the sixteenth resistor R16 is connected to the third control end of the second turn-off unit 133. The first end of the sixteenth resistor R16 is connected to the controlled end of the second switch tube Q2. The second end of the eighteenth resistor R18 is connected to the first conduction end of the ninth switch tube Q9. The controlled end of the ninth switch tube Q9, the first end of the twentieth resistor R20, the anode of the second voltage regulator ZD2, and the first end of the twenty-third resistor R23 are commonly connected. The second conduction end of the ninth switch tube Q9, the cathode of the second voltage regulator ZD2, the second end of the twenty-third resistor R23, and the cathode of the fourth diode D4 are commonly connected. The anode of the fourth diode D4 is the drive end of the second conduction unit. The common connection point of the second end of the twentieth resistor R20 and the first conduction end of the tenth switch tube Q10 is connected to the second control end of the second turn-off unit 133. The controlled end of the tenth switch tube Q10 and the first end of the twenty-fourth resistor R24 are commonly connected as the controlled end of the second conduction unit. The second conduction end of the tenth switch tube Q10 and the second end of the twenty-fourth resistor R24 are both grounded.

[0088] In yet another embodiment of the present application, the switch driving unit 12 includes: a fifth diode D5, a unidirectional conductive device D6, a second capacitor C2, a twenty-eighth resistor R28, a thirty-seventh resistor R37, a thirty-eighth resistor R38, an eleventh switch tube Q11, a twelfth switch tube Q12, a thirteenth switch tube Q13, a third capacitor C3, and a seventh capacitor C7.

[0089] Specifically, the anode of the fifth diode D5 is the first voltage input terminal of the switch driving unit 12. The cathode of the fifth diode D5 is connected to the first terminal 1 of the unidirectional conductive device D6. The third terminal 3 of the unidirectional conductive device D6 is connected to the first terminal of the third capacitor C3. The second terminal 2 of the unidirectional conductive device D6 and the second terminal of the seventh capacitor C7 are commonly connected as the voltage output terminal of the switch driving unit 12. The first terminal of the second capacitor C2, the first terminal of the twenty-eighth resistor R28, and the first conducting terminal of the eleventh switching transistor Q11 are commonly connected as the reference voltage input terminal of the switch driving unit 12. The second terminal of the second capacitor C2 is grounded. The second terminal of the twenty-eighth resistor R28, the first conducting terminal of the twelfth switching transistor Q12, the controlled terminal of the eleventh switching transistor Q11, and the controlled terminal of the thirteenth switching transistor Q13 are commonly connected. The first conducting terminal of the thirteenth switching transistor Q13 is connected to the second terminal of the third capacitor C3. The second terminal of the seventh capacitor C7, the second conducting terminal of the thirteenth switching transistor Q13, the second conducting terminal of the twelfth switching transistor Q12, and the second terminal of the thirty-eighth resistor R38 are all grounded. The second terminal of the thirty-eighth resistor R38, the second terminal of the thirty-seventh resistor R37, and the controlled terminal of the twelfth switching transistor Q12 are commonly connected. The first terminal of the thirty-seventh resistor R37 is the drive signal input terminal of the switch driving unit 12.

[0090] In this embodiment, the unidirectional conductive device D6 can be formed by connecting two diodes (diode Da and diode Db) in series. Among them, the anode of diode Da is the first terminal 1 of the unidirectional conductive device D6, and the common connection point of the cathode of diode Da and the anode of diode Db is the third terminal 3 of the unidirectional conductive device D6. The cathode of diode Db is the second terminal 2 of the unidirectional conductive device D6.

[0091] In another embodiment of the present application, the self-oscillation unit 15 includes: the twenty-sixth resistor R26, the first capacitor C1, the twenty-seventh resistor R27, the seventh diode D7, the thirty-third resistor R33, the twelfth capacitor C12, the comparator U2, the thirty-ninth resistor R39, and the fortieth resistor R40.

[0092] Specifically, the first end of the twenty-sixth resistor R26 is used to receive the operating voltage VCC of the self-oscillation unit 15. The second end of the twenty-sixth resistor R26 and the first end of the first capacitor C1 are commonly connected to the power supply terminal 6 of the comparator U2. The second end of the first capacitor C1 is grounded. The anode of the seventh diode D7, the second end of the thirty-third resistor R33, the output terminal 1 of the comparator U2, and the second end of the fortieth resistor R40 are commonly connected. The cathode of the seventh diode D7 is connected to the second end of the twenty-seventh resistor R27. The first end of the twenty-seventh resistor R27, the first end of the thirty-third resistor R33, the first end of the twelfth capacitor C12, and the inverting input terminal 4 of the comparator U2 are commonly connected. The second end of the twelfth capacitor C12 is grounded. The first end of the thirty-ninth resistor R39, the first end of the fortieth resistor R40, and the non-inverting input terminal 3 of the comparator U2 are commonly connected. The second end of the thirty-ninth resistor is connected to the reference voltage terminal 5 of the comparator U2. The ground terminal of the comparator U2 is grounded.

[0093] In another embodiment of the present application, the reference voltage unit 16 includes: an eighth diode D8, a twenty-ninth resistor R29, a fourth capacitor C4, a thirtieth resistor R30, an eleventh capacitor C11, a thirty-fifth resistor R35, a power supply chip U1, a thirty-first resistor R31, a thirty-fourth resistor R34, a thirty-sixth resistor R36, a ninth capacitor C9, and a tenth capacitor C10.

[0094] Specifically, the anode of the eighth diode D8 is connected to the positive electrode of the battery unit 200. The cathode of the eighth diode D8 is connected to the first end of the twenty-ninth resistor R29. The second end of the twenty-ninth resistor R29, the first end of the fourth capacitor C4, and the first end of the thirtieth resistor R30 are commonly connected to the input pin IN of the power supply chip U1. The second end of the thirtieth resistor R30, the first end of the eleventh capacitor C11, and the first end of the thirty-fifth resistor R35 are commonly connected to the enable pin EN of the power supply chip U1. The second end of the fourth capacitor C4, the second end of the eleventh capacitor C11, the second end of the thirty-fifth resistor R35, and the ground pin GND of the power supply chip U1 are all grounded. The first end of the thirty-first resistor R31, the first end of the thirty-fourth resistor R34, the first end of the ninth capacitor C9, and the first end of the tenth capacitor C10 are commonly connected to the output pin OUT of the power supply chip U1. The second end of the thirty-first resistor R31 is connected to the power status pin PG of the power supply chip U1. The second end of the thirty-fourth resistor R34 and the first end of the thirty-sixth resistor R36 are commonly connected to the feedback pin FB of the power supply chip U1. The second end of the thirty-sixth resistor R36, the second end of the ninth capacitor C9, and the second end of the tenth capacitor C10 are all grounded.

[0095] In another embodiment of the present application, the main control unit 11 may include a main control chip U3.

[0096] Specifically, the charging control pin CHG of the main control chip U3 is the charging control terminal of the main control unit 11, and the discharging control pin DSG of the main control chip is the discharging control terminal of the main control unit 11. In specific applications, the main control chip U3 can be a central processing unit (CPU), a micro controller unit (MCU), etc., and there is no limitation here.

[0097] As an example but not limitation, the power supply chip U1 can be a linear buck chip.

[0098] As an example but not limitation, the first switching transistor Q1 and the second switching transistor Q2 can both be NMOS transistors, the third switching transistor Q3 and the fourth switching transistor Q4 can both be depletion-type PMOS transistors, the fifth switching transistor Q5 and the sixth switching transistor Q6 can both be PNP bipolar transistors, the seventh switching transistor Q7 and the tenth switching transistor Q10 can both be NMOS transistors, the eighth switching transistor Q8 and the ninth switching transistor Q9 can both be PMOS transistors, the eleventh switching transistor Q11 can be an NMOS transistor, and the twelfth switching transistor Q12 can be a PNP bipolar transistor.

[0099] In other embodiments of the present application, the first switching transistor Q1 to the twelfth switching transistor Q12 can also be other types of switching transistors having the same switching characteristics as the switching transistors in the above embodiments, and there is no specific limitation on the specific types of the switching transistors here.

[0100] The following combines Figure 3 to detail the working principles of the various units in the battery management system 100:

[0101] The working principle of the self-excited oscillation unit 15 is as follows:

[0102] When the first end of the twenty-sixth resistor R26 receives the operating voltage VCC, the comparator U2 is powered on. When the comparator U2 is powered on, a reference voltage signal Vref will be output at the reference voltage terminal 5 of the comparator U2. After being divided by the thirty-ninth resistor R39 and the fortieth resistor R40, the reference voltage signal Vref is input to the non-inverting input terminal 3 of the comparator U2, making the non-inverting input terminal 3 of the comparator U2 at a high level. At this time, the inverting input terminal 4 of the comparator U2 remains at a low level due to the twelfth capacitor C12. Therefore, at this time, the output terminal 1 of the comparator U2 will output a high-level signal Vout_H. This high-level signal Vout_H charges the twelfth capacitor C12 through the twenty-seventh resistor R27 and the thirty-third resistor R33, causing the voltage at the inverting input terminal 4 of the comparator U2 to gradually increase. When the voltage at the inverting input terminal 4 of the comparator U2 is higher than the voltage at its non-inverting input terminal 3, the output terminal 1 of the comparator U2 outputs a low-level signal Vout_L. At this time, the voltage on the twelfth capacitor C12 will discharge through the thirty-third resistor R33, causing the voltage at the inverting input terminal 4 of the comparator U2 to gradually decrease. When the voltage at the inverting input terminal 4 of the comparator U2 is less than the voltage at its non-inverting input terminal 3, the output terminal 1 of the comparator U2 outputs a high-level signal Vout_H again. By repeatedly charging and discharging the twelfth capacitor C12 in this way, the output terminal 1 of the comparator U2 can output a PWM square wave signal, and this PWM square wave signal serves as the drive signal for the switch drive unit 12. It should be noted that the duty cycle of this PWM square wave signal can be adjusted.

[0103] The working principle of the reference voltage unit 16 is as follows:

[0104] Through the power supply chip U1, the voltage Vcell at the positive pole of the battery unit 200 can be reduced to the reference voltage Vr, and this reference voltage Vr serves as the reference voltage for the switch drive unit. The reference voltage Vr can be divided by the thirty-fourth resistor R34 and the thirty-sixth resistor R36, and the divided voltage will be fed back to the power supply chip U1 through the feedback pin FB of the voltage chip U1. The power supply chip U1 adjusts the reference voltage Vr based on this feedback voltage, thereby achieving the voltage stabilization effect on the reference voltage Vr.

[0105] In specific applications, by adjusting the resistance value of the thirty-fourth resistor R34 and / or the resistance value of the thirty-sixth resistor R36, the voltage value of the reference voltage Vr can be adjusted.

[0106] The working principle of the switch drive unit 12 is as follows:

[0107] The PWM square wave signal output by the self-oscillation unit 15 causes the twelfth switching transistor Q12 to switch between the conducting state and the cutoff state. Specifically, when the twelfth switching transistor Q12 is conducting, it will pull down the voltage at the controlled terminal of the thirteenth switching transistor Q13, causing the thirteenth switching transistor Q13 to be in the saturated conduction state. At this time, the voltage V3 at the second terminal of the third capacitor C3 is the saturated conduction voltage Vsat of the thirteenth switching transistor Q13 (usually less than 0.3 volts), that is, V3 = Vsat, and the voltage V1 at the third terminal of the unidirectional conducting device D6 (i.e., the first terminal of the third capacitor C3) is the difference between the voltage Vcell of the positive electrode of the battery unit 200 and the conduction voltage Vf1 of the diodes (including the fifth diode D5 and the diode Da), that is, V1 = Vcell - Vf1. At this time, the voltage across the third capacitor C3 is V1 - V3 = Vcell - Vf1 - Vsat. When the twelfth switching transistor Q12 is cutoff, it will pull up the controlled terminal of the eleventh switching transistor Q11 and the control terminal of the thirteenth switching transistor Q13. At this time, the thirteenth switching transistor Q13 is in the cutoff state and the eleventh switching transistor Q11 is in the conducting state. At this time, the voltage V3 at the second terminal of the third capacitor C3 will rise to the reference voltage Vr. Due to the charge retention characteristic of the capacitor, the voltage across the third capacitor C3 remains unchanged, and the voltage V1 at the third terminal of the unidirectional conducting device D6 will rise to Vr + Vcell - Vf1 - Vsat.

[0108] When the switching drive unit 12 raises the voltage V1 at the third terminal 3 of the unidirectional conducting device D6 to Vr + Vcell - Vf1 - Vsat, the seventh capacitor C7 can be charged through the unidirectional conducting device D6. At this time, the voltage at the first terminal of the seventh capacitor C7 is equal to the difference between V1 and the conduction voltage Vf2 of the diode Db, that is, equal to V1 - Vf2 = Vr + Vcell - Vf1 - Vsat - Vf2. This voltage is defined as the switching drive voltage Vboost. Due to the existence of the unidirectional conducting device D6, when the voltage V1 at the third terminal 3 of the unidirectional conducting device D6 decreases, the voltage V2 at the second terminal 2 of the unidirectional conducting device D6 will still remain at this switching drive voltage Vboost.

[0109] The working principle of the first conduction unit 132 is as follows:

[0110] When the charging pin CHG of the main control chip U3 outputs a high-level signal, the seventh switching transistor Q7 conducts. At this time, the controlled terminal of the eighth switching transistor Q8 is pulled low, and the eighth switching transistor Q8 also conducts. At this time, the switching drive voltage Vboost output by the switching drive unit 12 charges the controlled terminal of the first switching transistor Q1. The voltage of the controlled terminal of the first switching transistor Q1 is the difference between the switching drive voltage Vboost and the conduction voltage Vf3 of the third diode D3, that is, Vboost - Vf3. The voltage between the controlled terminal of the first switching transistor Q1 and its first conduction terminal is Vboost - Vf3 - Vcell = Vr - Vf1 - Vsat - Vf2 - Vf3. Thus, the first switching transistor Q1 can be quickly turned on, and then the charging circuit where the battery unit 200 is located is connected.

[0111] The working principle of the first turn-off unit 131 is as follows:

[0112] When the charging pin CHG of the main control chip U3 outputs a low-level signal, both the seventh switching transistor Q7 and the eighth switching transistor Q8 are turned off. Therefore, at this time, the switching drive voltage Vboost output by the switching drive unit 12 cannot charge the controlled terminal of the first switching transistor Q1. Since the fourth switching transistor Q4 is a depletion-type switching transistor, it can quickly return to the conducting state, and then pull down the controlled terminal of the fifth switching transistor Q5. The fifth switching transistor Q5 quickly discharges the charge of the controlled terminal of the first switching transistor Q1, and then quickly turns off the first switching transistor Q1. In this way, the charging circuit where the battery unit 200 is located can be cut off.

[0113] The working principle of the second conduction unit 134 is as follows:

[0114] When the discharging pin DSG of the main control chip U3 outputs a high-level signal, the tenth switching transistor Q10 conducts. At this time, the controlled terminal of the ninth switching transistor Q9 is pulled low, and the ninth switching transistor Q9 also conducts. At this time, the switching drive voltage Vboost output by the switching drive unit 12 charges the controlled terminal of the second switching transistor Q2. The voltage of the controlled terminal of the second switching transistor Q2 is the difference between the switching drive voltage Vboost and the conduction voltage Vf4 of the fourth diode D4, that is, Vboost - Vf4. The voltage between the controlled terminal of the second switching transistor Q2 and its first conduction terminal is Vboost - Vf4 - Vcell = Vr - Vf1 - Vsat - Vf2 - Vf4. Thus, the second switching transistor Q2 can be quickly turned on, and then the discharging circuit where the battery unit 200 is located is connected.

[0115] The working principle of the second turn-off unit 133 is as follows:

[0116] When the discharge pin DSG of the main control chip U3 outputs a low-level signal, the tenth switching transistor Q10 and the ninth switching transistor Q9 are both cut off. Therefore, at this time, the switching drive voltage Vboost output by the switching drive unit 12 cannot charge the controlled terminal of the second switching transistor Q2. Since the third switching transistor Q3 is a depletion-mode switching transistor, it can quickly return to the conducting state, and then pull down the controlled terminal of the sixth switching transistor Q6. The sixth switching transistor Q6 quickly discharges the charge at the controlled terminal of the second switching transistor Q2, and then quickly turns off the second switching transistor Q2, so that the discharge loop where the battery unit 200 is located can be cut off.

[0117] Those skilled in the art can clearly understand that, for the convenience and simplicity of description, only the above-mentioned division of each functional unit and module is used as an example. In actual applications, the above-mentioned functions can be allocated to different functional units and modules according to needs, that is, the internal structure of the battery management system is divided into different functional units or modules to complete all or part of the functions described above. In addition, the specific names of each functional unit and module are only for the convenience of mutual distinction and do not limit the protection scope of the present application. The specific working processes of the units and modules in the above system can refer to the corresponding processes in the foregoing method embodiments and will not be elaborated here.

[0118] In the above embodiments, the descriptions of the various embodiments have their own emphases. For the parts not detailed or recorded in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0119] Those of ordinary skill in the art can realize that the units and algorithm steps of the examples described in conjunction with the embodiments disclosed herein can be implemented by electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are executed in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered to exceed the scope of the present application.

[0120] The above-described embodiments are only used to illustrate the technical solutions of the present application and are not intended to limit them. Although the present application has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements for some of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application, and should all be included in the protection scope of the present application.

Claims

1. A battery management system for connecting battery cells, characterized in that, The battery management system includes: a main control unit, a switch driving unit, a switch control unit, and a switch unit; The main control unit is connected to the battery unit and the switch control unit, and is configured to output a switch control signal to the switch control unit; The switch driving unit is connected to the positive electrode of the battery unit and the switch control unit, and is configured to provide a switch driving voltage for the switch control unit; The switch control unit is connected to the switch unit, and is configured to control the switch unit to conduct or turn off according to the switch control signal; The switch unit is connected between the positive electrode of the battery unit and the positive charge and discharge port, and is configured to connect the charge and discharge loop where the battery unit is located when conducting, or to cut off the charge and discharge loop where the battery unit is located when turned off; The switch driving unit includes: a fifth diode, a unidirectional conductive device, a second capacitor, a twenty-eighth resistor, a thirty-seventh resistor, a thirty-eighth resistor, an eleventh switch tube, a twelfth switch tube, a thirteenth switch tube, a third capacitor, and a seventh capacitor; The anode of the fifth diode is the first voltage input terminal of the switch driving unit. The cathode of the fifth diode is connected to the first end of the unidirectional conductive device. The third end of the unidirectional conductive device is connected to the first end of the third capacitor. The second end of the unidirectional conductive device and the second end of the seventh capacitor are commonly connected as the voltage output terminal of the switch driving unit. The first end of the second capacitor, the first end of the twenty-eighth resistor, and the first conducting end of the eleventh switch tube are commonly connected as the reference voltage input terminal of the switch driving unit. The second end of the second capacitor is grounded. The second end of the twenty-eighth resistor, the first conducting end of the twelfth switch tube, the controlled end of the eleventh switch tube, and the controlled end of the thirteenth switch tube are commonly connected. The first conducting end of the thirteenth switch tube is connected to the second end of the third capacitor. The second end of the seventh capacitor, the second conducting end of the thirteenth switch tube, the second conducting end of the twelfth switch tube, and the second end of the thirty-eighth resistor are all grounded. The second end of the thirty-eighth resistor, the second end of the thirty-seventh resistor, and the controlled end of the twelfth switch tube are commonly connected. The first end of the thirty-seventh resistor is the driving signal input terminal of the switch driving unit; The battery management system further includes a self-excited oscillation unit connected to the switch driving unit; The self-excited oscillation unit is configured to provide a driving signal for the switch driving unit; Correspondingly, the switch driving unit is specifically configured to convert the reference voltage into the switch driving voltage under the drive of the driving signal; The self-excited oscillation unit includes: a twenty-sixth resistor, a first capacitor, a twenty-seventh resistor, a seventh diode, a thirty-third resistor, a twelfth capacitor, a comparator, a thirty-ninth resistor, and a fortieth resistor; The first end of the twenty-sixth resistor is used to receive the operating voltage of the self-excitation oscillation unit. The second end of the twenty-sixth resistor and the first end of the first capacitor are commonly connected to the power supply terminal of the comparator. The second end of the first capacitor is grounded. The anode of the seventh diode, the second end of the thirty-third resistor, the output terminal of the comparator, and the second end of the fortieth resistor are commonly connected. The cathode of the seventh diode is connected to the second end of the twenty-seventh resistor. The first end of the twenty-seventh resistor, the first end of the thirty-third resistor, the first end of the twelfth capacitor, and the inverting input terminal of the comparator are commonly connected. The second end of the twelfth capacitor is grounded. The first end of the thirty-ninth resistor, the first end of the fortieth resistor, and the non-inverting input terminal of the comparator are commonly connected. The second end of the thirty-ninth resistor is connected to the reference voltage terminal of the comparator. The ground terminal of the comparator is grounded.

2. The battery management system according to claim 1, wherein The battery management system further includes a reference voltage unit connected to the positive electrode of the battery unit and the switch driving unit; The reference voltage unit is used to convert the voltage of the positive electrode of the battery unit into the reference voltage and provide the reference voltage for the switch driving unit.

3. The battery management system according to any one of claims 1 to 2, characterized in that, The switch unit includes: a first switch tube and a second switch tube; The first conduction end of the first switch tube is connected to the positive electrode of the battery unit. The second conduction end of the first switch tube is connected to the first conduction end of the second switch tube. The controlled end of the first switch tube is connected to the switch control unit. The first switch tube is used to connect or disconnect the charging circuit where the battery unit is located when the battery unit is charging; The second conduction end of the second switch tube is connected to the positive charge and discharge port. The controlled end of the second switch tube is connected to the switch control unit. The second switch tube is used to connect or disconnect the discharge circuit where the battery unit is located when the battery unit is discharging.

4. The battery management system according to claim 3, characterized in that, The switch control unit includes: a first turn-off unit, a first turn-on unit, a second turn-off unit, and a second turn-on unit; The first control end of the first turn-off unit is connected to the positive electrode of the battery unit. The second control end and the third control end of the first turn-off unit are both connected to the first turn-on unit. The controlled end of the first turn-on unit is connected to the charging control end of the main control unit. The driving end of the first turn-on unit is connected to the switch driving unit. The first control end of the first turn-on unit is connected to the positive electrode of the battery unit. The second control end of the first turn-on unit is connected to the controlled end of the first switch tube; The first control end of the second turn-off unit is connected to the second conduction end of the second switch tube. The second control end and the third control end of the second turn-off unit are both connected to the second turn-on unit. The controlled end of the second turn-on unit is connected to the discharge control end of the main control unit. The driving end of the second turn-on unit is connected to the switch driving unit. The first control end of the second turn-on unit is connected to the second conduction end of the second switch tube. The second control end of the second turn-on unit is connected to the controlled end of the second switch tube.

5. The battery management system according to claim 4, characterized in that The first turn-off unit includes: a first resistor, an eighth resistor, a first diode, a fourth switching tube, a second resistor, a seventh resistor, a fifth switching tube, an eleventh resistor, and a twelfth resistor; The first end of the first resistor, the first conducting end of the fourth switching tube, and the first end of the second resistor are commonly connected as the first control end of the first turn-off unit. The second end of the first resistor, the first end of the eighth resistor, and the controlled end of the fourth switching tube are commonly connected. The second end of the eighth resistor is connected to the anode of the first diode, and the cathode of the first diode is the second control end of the first turn-off unit. The second conducting end of the fourth switching tube, the first end of the seventh resistor, and the first end of the eleventh resistor are commonly connected. The second end of the seventh resistor is connected to the controlled end of the fifth switching tube. The first conducting end of the fifth switching tube is connected to the second end of the second resistor. The second conducting end of the fifth switching tube is connected to the first end of the twelfth resistor. The second end of the eleventh resistor and the second end of the twelfth resistor are commonly connected as the third control end of the first turn-off unit; The first conducting unit includes: a fourth resistor, a third voltage-regulating tube, a fifteenth resistor, a seventeenth resistor, an eighth switching tube, a nineteenth resistor, a twenty-second resistor, a fourth voltage-regulating tube, a seventh switching tube, a twenty-first resistor, and a third diode; The anode of the third voltage-regulating tube and the first end of the fourth resistor are commonly connected as the first control end of the first conducting unit. The cathode of the third voltage-regulating tube, the first end of the seventeenth resistor, the second end of the fourth resistor, and the common connection point of the second end of the fifteenth resistor are connected to the third control end of the first turn-off unit. The first end of the fifteenth resistor is the second control end of the first conducting unit. The second end of the seventeenth resistor is connected to the first conducting end of the eighth switching tube. The controlled end of the eighth switching tube, the second end of the nineteenth resistor, the anode of the fourth voltage-regulating tube, and the first end of the twenty-second resistor are commonly connected. The second conducting end of the eighth switching tube, the cathode of the fourth voltage-regulating tube, the second end of the twenty-second resistor, and the cathode of the third diode are commonly connected. The anode of the third diode is the driving end of the first conducting unit. The common connection point of the first end of the nineteenth resistor and the first conducting end of the seventh switching tube is connected to the second control end of the first turn-off unit. The controlled end of the seventh switching tube and the first end of the twenty-first resistor are commonly connected as the controlled end of the first conducting unit. The second conducting end of the seventh switching tube and the second end of the twenty-first resistor are both grounded.

6. The battery management system according to claim 4, characterized in that, The second turn-off unit includes: a third resistor, a sixth resistor, a second diode, a third switching tube, a fifth resistor, a tenth resistor, a sixth switching tube, a thirteenth resistor, and a fourteenth resistor; The first end of the third resistor, the first conducting end of the third switching transistor, and the first end of the fifth resistor are commonly connected as the first control end of the second turn-off unit. The second end of the third resistor, the first end of the sixth resistor, and the controlled end of the third switching transistor are commonly connected. The second end of the sixth resistor is connected to the anode of the second diode, and the cathode of the second diode is the second control end of the second turn-off unit. The second conducting end of the third switching transistor, the first end of the tenth resistor, and the first end of the thirteenth resistor are commonly connected. The second end of the tenth resistor is connected to the controlled end of the sixth switching transistor. The first conducting end of the sixth switching transistor is connected to the second end of the fifth resistor. The second conducting end of the sixth switching transistor is connected to the first end of the fourteenth resistor. The second end of the thirteenth resistor and the second end of the fourteenth resistor are commonly connected as the third control end of the second turn-off unit; The second conducting unit includes: a ninth resistor, a first voltage regulator diode, a sixteenth resistor, an eighteenth resistor, a ninth switching transistor, a twentieth resistor, a twenty-third resistor, a second voltage regulator diode, a tenth switching transistor, a twenty-fourth resistor, and a fourth diode; The anode of the first voltage regulator diode and the first end of the ninth resistor are commonly connected to serve as the first control end of the second conducting unit. The common connection point of the cathode of the first voltage regulator diode, the first end of the eighteenth resistor, the second end of the ninth resistor, and the second end of the sixteenth resistor is connected to the third control end of the second turn-off unit. The first end of the sixteenth resistor is connected to the controlled end of the second switching transistor. The second end of the eighteenth resistor is connected to the first conducting end of the ninth switching transistor. The controlled end of the ninth switching transistor, the first end of the twentieth resistor, the anode of the second voltage regulator diode, and the first end of the twenty-third resistor are commonly connected. The second conducting end of the ninth switching transistor, the cathode of the second voltage regulator diode, the second end of the twenty-third resistor, and the cathode of the fourth diode are commonly connected. The anode of the fourth diode is the drive end of the second conducting unit. The common connection point of the second end of the twentieth resistor and the first conducting end of the tenth switching transistor is connected to the second control end of the second turn-off unit. The controlled end of the tenth switching transistor and the first end of the twenty-fourth resistor are commonly connected to serve as the controlled end of the second conducting unit. The second conducting end of the tenth switching transistor and the second end of the twenty-fourth resistor are both grounded.

7. The battery management system according to claim 2, wherein The reference voltage unit includes: an eighth diode, a twenty-ninth resistor, a fourth capacitor, a thirtieth resistor, an eleventh capacitor, a thirty-fifth resistor, a power supply chip, a thirty-first resistor, a thirty-fourth resistor, a thirty-sixth resistor, a ninth capacitor, and a tenth capacitor; The anode of the eighth diode is connected to the positive electrode of the battery cell, the cathode of the eighth diode is connected to the first end of the twenty-ninth resistor, the second end of the twenty-ninth resistor, the first end of the fourth capacitor, and the first end of the thirtieth resistor are commonly connected to the input pin of the power supply chip, the second end of the thirtieth resistor, the first end of the eleventh capacitor, and the first end of the thirty-fifth resistor are commonly connected to the enable pin of the power supply chip, the second end of the fourth capacitor, the second end of the eleventh capacitor, the second end of the thirty-fifth resistor, and the ground pin of the power supply chip are all grounded, the first end of the thirty-first resistor, the first end of the thirty-fourth resistor, the first end of the ninth capacitor, and the first end of the tenth capacitor are commonly connected to the output pin of the power supply chip, the second end of the thirty-first resistor is connected to the power supply status pin of the power supply chip, the second end of the thirty-fourth resistor and the first end of the thirty-sixth resistor are commonly connected to the feedback pin of the power supply chip, and the second end of the thirty-sixth resistor, the second end of the ninth capacitor, and the second end of the tenth capacitor are all grounded.

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