Switching circuit, battery management system, battery pack, electrical equipment and control method

Abstract

The present application provides a switching circuit, including a first switch tube, a control module and a discharge module. The first switch tube is arranged in the main circuit loop and is electrically connected to the control module and the discharge module respectively. The control module includes a first pin, and the control module is configured to output a voltage signal through the first pin, and the voltage signal is used to indicate that the first switch tube is turned on or off. Among them, the voltage signal includes a first voltage signal, and the first voltage signal is used to indicate that the first switch tube is turned off. When the first pin outputs the first voltage signal, the first switch tube discharges through the discharge module. The present application also provides a battery management system, a battery pack, an electrical device and a switch circuit control method. The present application can improve the turn-off speed of the switch tube.

Description

Technical Field

[0001] The present application relates to the field of battery technology, and in particular to a switching circuit, a battery management system, a battery pack, an electrical device, and a switching circuit control method. Background Art

[0002] A battery management system (BMS) manages battery charging and discharging. In a BMS, a driver circuit controls a switching transistor, such as a MOS transistor, as the positive electrode switch to output the battery voltage. When the switch is turned off, it must be shut down as quickly as possible to avoid prolonged overpower operation, which could damage the switch. In related technologies, using a driver circuit to shut down a switch has been difficult to achieve. Summary of the Invention

[0003] In view of this, the present application provides a switching circuit, a battery management system, a battery pack, an electrical device, and a switching circuit control method to improve the turn-off speed of the switching tube.

[0004] One aspect of the present application provides a switching circuit, comprising a first switching transistor, a control module, and a discharge module. The first switching transistor is disposed in a main circuit loop and is electrically connected to the control module and the discharge module, respectively. The control module includes a first pin, configured to output a voltage signal through the first pin, the voltage signal being used to indicate whether the first switching transistor is turned on or off. The voltage signal includes a first voltage signal, the first voltage signal being used to indicate whether the first switching transistor is turned off. When the first pin outputs the first voltage signal, the first switching transistor discharges through the discharge module.

[0005] In the above embodiment, by providing the discharge module, when the first switch tube is turned off, the discharge module discharges the first switch tube, thereby quickly discharging the charge stored in the first switch tube and improving the turn-off speed of the first switch tube.

[0006] In some embodiments of the present application, the discharge module includes a primary discharge circuit. The two ends of the primary discharge circuit are electrically connected to the first end of the first switching tube and the second end of the first switching tube, respectively. The first end of the first switching tube is also electrically connected to the first pin for receiving the voltage signal, and the third end of the first switching tube is electrically connected to the first end of the battery. The primary discharge circuit includes a second switching tube, which is electrically connected to the first pin for receiving the voltage signal. When the second switching tube is turned on, the first switching tube discharges through the primary discharge circuit.

[0007] In the above embodiment, the primary discharge circuit is used to accelerate the discharge of charge between the first terminal and the second terminal of the first switch tube. When the first switch tube is turned off, discharging the first switch tube through the primary discharge circuit can increase the turn-off speed of the first switch tube.

[0008] In some embodiments of the present application, the primary discharge circuit further includes a first resistor and a second resistor, and the first resistor, the second resistor and the second switch tube are connected in series between the first end of the first switch tube and the second end of the first switch tube.

[0009] In the above embodiment, the first resistor is used to reduce the speed of driving the first switch on and off to avoid oscillation. The second resistor is a bleeder resistor for the first switch, used to discharge the charge between the first terminal of the first switch and the second terminal of the second switch to increase the turn-off speed of the first switch.

[0010] In some embodiments of the present application, the discharge module further includes a secondary discharge circuit, the two ends of which are electrically connected to the first end of the first switching transistor and the second end of the first switching transistor, respectively. The secondary discharge circuit includes a third switching transistor, the first end of which is electrically connected to the third end of the first switching transistor, and the second end of which is electrically connected to the second end of the first switching transistor. When the third switching transistor is turned on, the first switching transistor also discharges through the secondary discharge circuit.

[0011] In the above embodiment, the secondary discharge circuit is used to discharge the first switching transistor, accelerating the discharge of charge between the first terminal of the first switching transistor and the second terminal of the first switching transistor. During the shutdown process of the first switching transistor, discharging the first switching transistor through the secondary discharge circuit can further increase the shutdown speed of the first switching transistor.

[0012] In some embodiments of the present application, the secondary discharge circuit further includes a first resistor and a third resistor, and the first resistor, the third resistor and the third switch tube are connected in series between the first end of the first switch tube and the second end of the first switch tube.

[0013] In the above embodiment, the third resistor is a discharge resistor of the first switch tube, which is used to discharge the charge between the first end of the first switch tube and the second end of the second switch tube to further improve the turn-off speed of the first switch tube.

[0014] In some embodiments of the present application, a fourth switch tube and a fourth resistor are further included, and the fourth switch tube and the fourth resistor are connected in series between the third end of the first switch tube and the first end of the third switch tube.

[0015] In the above embodiment, the fourth resistor is used to provide a driving current to the first end of the third switch tube.

[0016] Some embodiments of the present application further include a charging module, wherein the charging module includes a fifth resistor and a capacitor unit, wherein the fifth resistor and the capacitor unit are connected in series between the first end of the fourth switch tube and the second end of the third switch tube.

[0017] In the above embodiment, the fifth resistor is used to provide a driving current to the first terminal of the fourth switch tube. The capacitor unit is used to provide a driving current to the fourth switch tube.

[0018] In some embodiments of the present application, a first diode is further included, wherein the anode of the first diode is electrically connected to the first end of the fourth switch tube, and the cathode of the first diode is electrically connected to the third end of the first switch tube and the second end of the fourth switch tube respectively.

[0019] In the above embodiment, the first diode is used to provide a discharge circuit for the capacitor unit, and at the same time ensures that the fourth switch tube will not be reversely broken down when the capacitor unit is discharging.

[0020] In some embodiments of the present application, the discharge module further includes a three-stage discharge circuit. The three-stage discharge circuit includes a first resistor and a sixth resistor. The first resistor and the sixth resistor are connected in series between the first terminal of the first switching transistor and the second terminal of the first switching transistor, and the first switching transistor discharges through the three-stage discharge circuit.

[0021] In the above embodiment, the first switch tube can be discharged through a three-stage discharge circuit to further improve the turn-off speed of the first switch tube. The sixth resistor serves as a bleeder resistor for the first switch tube. When the first pin outputs a first voltage signal indicating the turn-off of the first switch tube, the voltage between the first terminal of the first switch tube and the second terminal of the first switch tube can be fixed at a low level, making the voltage more stable and avoiding circuit instability caused by voltage fluctuation.

[0022] In some embodiments of the present application, a second diode is further included, wherein an anode of the second diode is electrically connected to the first pin, and a cathode of the second diode is electrically connected to the first end of the first switch tube.

[0023] In the above embodiment, the second diode is an anti-reverse diode, which has an anti-reverse function and can prevent the high voltage pulse from the battery external device from directly impacting the first pin, so that the first pin has sufficient high voltage pulse protection capability.

[0024] In some embodiments of the present application, a seventh resistor and an eighth resistor are further included, wherein the first end of the seventh resistor is electrically connected to the first pin, the second end of the seventh resistor is electrically connected to the anode of the second diode, the first end of the second switch tube and the first end of the eighth resistor respectively, and the second end of the eighth resistor is electrically connected to the second end of the first switch tube.

[0025] In the above embodiment, the seventh resistor and the eighth resistor serve as bleeder resistors for the second switching transistor. The seventh resistor can also serve as a current-limiting resistor, used to limit the current in its branch circuit, thereby preventing the first pin from outputting an excessively large instantaneous current, which could cause the first pin to output an output current exceeding the rated current. The eighth resistor can also serve as a pull-down resistor at the first terminal of the second switching transistor, to prevent the second switching transistor from being mis-conducted.

[0026] One aspect of the present application provides a battery management system, comprising: a controller and the switching circuit provided in the present application. The controller is electrically connected to a control module, and the control module receives a first signal from the controller, the first signal being configured to instruct the control module to output a first voltage signal.

[0027] One aspect of the present application provides a battery pack, comprising: a battery cell module and the battery management system provided in the present application. The battery cell module includes at least one battery cell, is electrically connected to the battery management system, and is used to power the battery management system.

[0028] One aspect of the present application provides an electrical device, which includes: a load, and the battery pack provided in the present application, wherein the battery pack is electrically connected to the load and is used to supply power to the load.

[0029] One aspect of the present application provides a switching circuit control method, which is used to control the switching circuit provided in the present application. The control method includes: when the first pin outputs a first voltage signal, controlling the second switching tube to turn on, and the charge between the first end of the first switching tube and the second end of the first switching tube is discharged through the first-level discharge circuit.

[0030] In some embodiments of the present application, when the voltage between the third end of the first switch tube and the second end of the first switch tube is greater than or equal to a first threshold voltage, the third switch tube and the fourth switch tube are controlled to be turned on, and the charge between the first end of the first switch tube and the second end of the first switch tube is also discharged through the secondary discharge circuit.

[0031] In some embodiments of the present application, when the third switch tube is turned on, the charging module is in a charging state, and when the charge between the first end of the first switch tube and the second end of the first switch tube is released, the charging module stops charging.

[0032] The switching circuit, battery management system, battery pack, electrical device, and switching circuit control method of the present application are configured by providing a first switching tube, a control module, and a discharge module. The control module includes a first pin, and is configured to output a voltage signal through the first pin, which is used to indicate whether the first switching tube is turned on or off. The voltage signal includes a first voltage signal, which is used to indicate that the first switching tube is turned off. When the first pin outputs the first voltage signal, the first switching tube is discharged through the discharge module. When the first switching tube is turned off, the discharge module discharges the first switching tube, achieving rapid discharge of the charge stored in the first switching tube, thereby improving the turn-off speed of the first switching tube. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present application.

[0034] Figure 1 is a schematic structural diagram of a switch circuit provided in an embodiment of the present application;

[0035] Figure 2 is a schematic diagram of the circuit structure of the switch circuit provided in an embodiment of the present application in the first scenario;

[0036] Figure 3 2 is a schematic diagram of the circuit structure of the switch circuit provided in an embodiment of the present application in the second scenario;

[0037] Figure 4 2 is a schematic diagram of the circuit structure of the switch circuit provided in the embodiment of the present application in the third scenario;

[0038] Figure 5 2 is a schematic diagram of the circuit structure of the switch circuit provided in an embodiment of the present application in the fourth scenario;

[0039] Figure 6 This is a schematic diagram of the structure of the battery management system provided in an embodiment of the present application;

[0040] Figure 7 is a schematic structural diagram of a battery pack provided in an embodiment of the present application;

[0041] Figure 8 This is a schematic diagram of the structure of the electrical equipment provided in the embodiment of the present application;

[0042] Figure 9 This is a flow chart of a switch circuit control method provided in an embodiment of the present application;

[0043] Figure 10 This is another flow chart of the switch circuit control method provided in an embodiment of the present application. DETAILED DESCRIPTION

[0044] A battery management system manages battery charge and discharge. Within a battery management system, an MCU controls the on / off switching of switches such as MOSFETs, connecting and disconnecting the battery from external devices (including power consumers and chargers) to manage battery discharge and charging. When a switch is turned off, it must be turned off as quickly as possible to prevent prolonged operation in an overpowered state, which could damage the switch.

[0045] In the related art, when using a driver circuit to turn off a switch, achieving rapid shutdown requires high performance from the driver circuit, which in turn increases costs. However, driver circuits with average performance cannot achieve the desired rapid shutdown. Therefore, achieving rapid shutdown of the switch is difficult in the related art.

[0046] To address the aforementioned technical issues, an embodiment of the present application provides a switching circuit that discharges the charge in the switch tube through a discharge module when the switch tube is turned off, thereby rapidly discharging the charge in the switch tube and improving the turn-off speed of the switch tube. Thus, the switch tube can be turned off quickly.

[0047] The following, in conjunction with the accompanying drawings, clearly and completely describes the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without making creative work are within the scope of protection of this application. In the absence of conflict, the following embodiments and their technical features can be combined with each other.

[0048] See also Figure 1 , Figure 1 It is a structural diagram of the switching circuit provided in an embodiment of the present application. Figure 1 In the embodiment, the switching circuit includes a first switching tube Q1, a control module 101 and a discharge module 102, wherein the first switching tube Q1 is arranged in the main circuit loop, which is a loop composed of the positive electrode B+, P+ port of the battery, the load 103, the P- port and the negative electrode B- of the battery, that is, the main circuit loop is: B+→P+ port→load 103→P- port→B-. It should be noted that the P+ port and the P- port can be two ports for connecting the battery to an external device. In the embodiment of the present application, the load 103 can be an analog load. In some embodiments, according to specific needs, the load can also be a digital load.

[0049] In the embodiment of the present application, the first switch Q1 can be used as a positive electrode switch of the battery to output the battery voltage. By turning the first switch Q1 on or off, the battery voltage can be controlled to provide power. When the first switch Q1 is on, the battery voltage can be output to power the power-consuming device (load 103). When the first switch Q1 is off, the battery voltage cannot be output, and no power is provided.

[0050] The first switch Q1 is electrically connected to the control module 101 and the discharge module 102, respectively. The control module 101 may be an AFE and include a first pin DSG. The control module 101 may be configured to output a voltage signal through the first pin DSG, which is used to indicate whether the first switch Q1 is turned on or off. Specifically, different voltage signals output through the first pin DSG can indicate whether the first switch Q1 is turned on or off. For example, a voltage signal greater than or equal to a first threshold voltage output through the first pin DSG can be considered a high voltage signal, indicating that the first switch Q1 is turned on; a voltage signal less than or equal to a second threshold voltage output through the first pin DSG can be considered a low voltage signal, indicating that the first switch Q1 is turned off, where the second threshold voltage is lower than the first threshold voltage. For example, a voltage signal of approximately 12V output through the first pin DSG turns the first switch Q1 on, while a voltage signal of approximately 0V output through the first pin DSG turns the first switch Q1 off.

[0051] It should be noted that the above-mentioned voltage signal may include a first voltage signal, which is used to instruct the first switch tube Q1 to turn off. That is, when the first pin DSG outputs the first voltage signal, the first voltage signal may be a low voltage signal, such as a voltage signal of approximately 0V, which is used to instruct the first switch tube Q1 to turn off. In addition, when the first pin DSG outputs the first voltage signal, it instructs the first switch tube Q1 to turn off. When the first switch tube Q1 switches from the on state to the off state, the first switch tube Q1 cannot be completely turned off immediately. At this time, the first switch tube Q1 needs to discharge the charge stored in the parasitic capacitor. After the charge is completely discharged, the first switch tube Q1 is completely turned off. The time for the first switch tube Q1 to be turned off should not be too long, otherwise the first switch tube Q1 will be damaged due to the first switch tube Q1 being in an overpower state for a long time.

[0052] By providing the discharge module 102, when the first switch Q1 is about to be turned off, the first switch Q1 can be discharged through the discharge module 102 to accelerate the discharge of the charge stored in the parasitic capacitance of the first switch Q1. For example, during normal operation, the first pin DSG outputs a high voltage signal, the first switch Q1 is turned on and is in the on state, and the main circuit loop operates normally. When there is a need to turn off the first switch Q1, such as when the user normally turns off the first switch Q1, or when overcurrent, high current, or high voltage protection occurs, the first switch Q1 needs to be turned off to avoid burning the battery.

[0053] The first pin DSG of the control module 101 outputs a low-voltage signal. This low-voltage signal comes from the controller in the battery management system. The controller sends a digital signal to the control module 101. After receiving the digital signal, the control module 101 outputs an analog low-voltage signal, such as a low-voltage signal of approximately 0V, through the first pin DSG. This low-voltage signal is used to instruct the first switch Q1 to turn off. During the process of turning off the first switch Q1, the charge between the first terminal and the second terminal of the first switch Q1 is discharged through the discharge module 102. After the charge between the first terminal and the second terminal of the first switch Q1 is completely discharged, the first switch Q1 is completely turned off. Therefore, discharging through the discharge module 102 can improve the turn-off speed of the first switch Q1.

[0054] It will be appreciated that in the embodiments of the present application, by providing a first switch tube Q1, a control module 101, and a discharge module 102, the control module 101 is configured to output a voltage signal via a first pin DSG, which is used to indicate whether the first switch tube Q1 is turned on or off. The voltage signal includes a first voltage signal, which is used to indicate whether the first switch tube Q1 is turned off. When the first pin DSG outputs the first voltage signal, the first switch tube Q1 can be discharged through the discharge module 102. When the first switch tube Q1 is turned off, the discharge module 102 discharges the first switch tube Q1, thereby achieving rapid discharge of charge, specifically rapid discharge of charge between the first terminal and the second terminal of the first switch tube Q1, thereby improving the turn-off speed of the first switch tube Q1.

[0055] See also Figure 2 , Figure 2 This is a schematic diagram of the circuit structure of the switching circuit provided in an embodiment of the present application in the first scenario. Figure 2In the embodiment, the discharge module 102 includes a primary discharge loop 201, wherein the two ends of the primary discharge loop 201 are electrically connected to the first end of the first switch tube Q1 and the second end of the first switch tube Q1, respectively. The first end of the first switch tube Q1 is also electrically connected to the first pin DSG for receiving a voltage signal. The third end of the first switch tube Q1 is used to electrically connect to the first end of the battery. For example, the first end of the battery can be the positive electrode B+ of the battery, and the second end of the battery can be the negative electrode B- of the battery. The third end of the first switch tube Q1 can be used to connect to the positive electrode B+ of the battery to serve as the positive electrode switch of the battery to output the battery voltage.

[0056] Optionally, the first switch transistor Q1 may be a MOS transistor, wherein the first terminal of the first switch transistor Q1 may be the gate of the MOS transistor, the second terminal of the first switch transistor Q1 may be the source of the MOS transistor, and the third terminal of the first switch transistor Q1 may be the drain of the MOS transistor. In some embodiments, the first switch transistor may also be another type of electronic switch dedicated transistor, such as a triode, or another type of power switch transistor.

[0057] Among them, the primary discharge circuit 201 is used to accelerate the discharge of charge between the first end and the second end of the first switch tube Q1. When the first switch tube Q1 is a MOS tube, the primary discharge circuit 201 can accelerate the discharge of charge between the gate and source of the MOS tube.

[0058] The primary discharge circuit 201 includes a second switch Q2, which is electrically connected to the first pin DSG and is configured to receive a voltage signal output by the first pin DSG. When the second switch Q2 is turned on, the first switch Q1 can be discharged through the primary discharge circuit 201. That is, the charge between the first terminal of the first switch Q1 and the second terminal of the first switch Q1 is discharged through the primary discharge circuit 201. When the first switch Q1 is turned off, the first switch Q1 is discharged through the primary discharge circuit 201, thereby improving the turn-off speed of the first switch Q1.

[0059] Optionally, the primary discharge circuit 201 may further include a first resistor R1 and a second resistor R2, wherein the first resistor R1, the second resistor R2, and the second switch transistor Q2 are connected in series between the first end of the first switch transistor Q1 and the second end of the first switch transistor Q1. Specifically, the first end of the first resistor R1 is electrically connected to the first end of the first switch transistor Q1, the second end of the first resistor R1 is electrically connected to the second end of the second switch transistor Q2, the third end of the second switch transistor Q2 is electrically connected to the first end of the second resistor R2, the first end of the second switch transistor Q2 is electrically connected to the first pin DSG, and the second end of the second resistor R2 is electrically connected to the second end of the first switch transistor Q1.

[0060] Optionally, the second switch transistor Q2 may be a MOS transistor, wherein the first end of the second switch transistor Q2 may be the gate of the MOS transistor, the second end of the second switch transistor Q2 may be the source of the MOS transistor, and the third end of the second switch transistor Q2 may be the drain of the MOS transistor. In some embodiments, the second switch transistor may also be another type of electronic switch dedicated transistor, such as a triode, or another type of power switch transistor.

[0061] It should be noted that in the embodiment of the present application, the first resistor R1 is used to reduce the speed of driving the first switch Q1 on and off to avoid oscillation. The second resistor R2 is a bleeder resistor for the first switch Q1, which is used to discharge the charge between the first terminal of the first switch Q1 and the second terminal of the second switch Q2 to increase the turn-off speed of the first switch Q1.

[0062] For example, when the first pin DSG outputs a first voltage signal, such as a low voltage signal of approximately 0V, the voltage at the first end of the second switch tube Q2 is a low voltage, such as 0V. Since the first switch tube Q1 cannot be turned off instantaneously when turned off, the voltage at the second end of the second switch tube Q2 does not change suddenly. At this time, the voltage at the second end of the second switch tube Q2 is a high voltage, such as 12V. A voltage difference exists between the first end of the second switch tube Q2 and the second end of the second switch tube Q2, causing the second switch tube Q2 to turn on. As a result, the charge between the first end of the first switch tube Q1 and the second end of the first switch tube Q1 is discharged through the first resistor R1, the second switch tube Q2, and the second resistor R2, thereby increasing the turn-off speed of the first switch tube Q1.

[0063] See also Figure 3 , Figure 3 This is a schematic diagram of the circuit structure of the switching circuit provided in an embodiment of the present application in the second scenario. Figure 3 In the embodiment, the discharge module 102 may further include a secondary discharge circuit 202, the two ends of which are electrically connected to the first end of the first switch tube Q1 and the second end of the first switch tube Q1, respectively. The secondary discharge circuit 202 is used to discharge the first switch tube Q1 and accelerate the discharge of charge between the first end of the first switch tube Q1 and the second end of the first switch tube Q1.

[0064] The secondary discharge circuit 202 may include a third switch Q3, a first end of the third switch Q3 electrically connected to the third end of the first switch Q1, and a second end of the third switch Q3 electrically connected to the second end of the first switch Q1. When the third switch Q3 is turned on, the first switch Q1 can discharge through the secondary discharge circuit 202. That is, the charge between the first end and the second end of the first switch Q1 is discharged through the secondary discharge circuit 202. When the first switch Q1 is turned off, the first switch Q1 is discharged through the secondary discharge circuit 202, which can further improve the turn-off speed of the first switch Q1.

[0065] Optionally, the secondary discharge circuit 202 may further include a first resistor R1 and a third resistor R3, wherein the first resistor R1, the third resistor R3, and the third switch Q3 are connected in series between the first end of the first switch Q1 and the second end of the first switch Q1. Specifically, the first end of the first resistor R1 is electrically connected to the first end of the first switch Q1, the second end of the first resistor R1 is electrically connected to the first end of the third resistor R3, and the second end of the third resistor R3 is electrically connected to the third end of the third switch Q3.

[0066] Optionally, the third switch tube Q3 may be a triode, wherein the first end of the third switch tube Q3 may be the base of the triode, the second end of the third switch tube Q3 may be the emitter of the triode, and the third end of the third switch tube Q3 may be the collector of the triode. In some embodiments, the third switch tube may also be another type of electronic switch tube, such as another type of triode, or another type of power switch tube.

[0067] It should be noted that, in the embodiment of the present application, the third resistor R3 is a discharge resistor of the first switch tube Q1, which is used to discharge the charge between the first end of the first switch tube Q1 and the second end of the second switch tube Q2 to increase the turn-off speed of the first switch tube Q1.

[0068] When the third switch Q3 is turned on, the charge between the first terminal of the first switch Q1 and the second terminal of the first switch Q1 is discharged through the first resistor R1, the third resistor R3 and the third switch Q3 to further increase the turn-off speed of the first switch Q1.

[0069] Optionally, the switching circuit may further include a fourth switching transistor Q4 and a fourth resistor R4, wherein the fourth switching transistor Q4 and the fourth resistor R4 are connected in series between the third end of the first switching transistor Q1 and the first end of the third switching transistor Q3. Specifically, the first end of the fourth switching transistor Q4 is electrically connected to the second end of the third switching transistor Q3, the second end of the fourth switching transistor Q4 is electrically connected to the third end of the first switching transistor Q1, the third end of the fourth switching transistor Q4 is electrically connected to the first end of the fourth resistor R4, and the second end of the fourth resistor R4 is electrically connected to the first end of the third switching transistor Q3.

[0070] The fourth resistor R4 is used to provide a driving current to the first terminal of the third switch Q3. For example, when the third switch Q3 is a transistor, the fourth resistor R4 can serve as a base resistor of the third switch Q3, and is used to inject a current, i.e., a bias current, into the base of the third switch Q3.

[0071] When the fourth switch tube Q4 is turned on, a driving current flows through the fourth resistor R4 to the first terminal of the third switch tube Q3. When the voltage between the first terminal of the third switch tube Q3 and the second terminal of the third switch tube Q3 reaches the turn-on voltage Vbe1 (typically 0.7V), the third switch tube Q3 is turned on. The charge between the first terminal of the first switch tube Q1 and the second terminal of the first switch tube Q1 is further discharged through the first resistor R1, the third resistor R3, and the third switch tube Q3, thereby further improving the turn-off speed of the first switch tube Q1.

[0072] Optionally, the fourth switch tube Q4 may be a triode, wherein the first end of the fourth switch tube Q4 may be the base of the triode, the second end of the fourth switch tube Q4 may be the emitter of the triode, and the third end of the fourth switch tube Q4 may be the collector of the triode. In some embodiments, the fourth switch tube may also be another type of electronic switch tube, such as another type of triode, or another type of power switch tube.

[0073] See also Figure 4 , Figure 4 This is a schematic diagram of the circuit structure of the switching circuit provided in an embodiment of the present application in the third scenario. Figure 4 In the embodiment, the switching circuit may further include a charging module 104, which may include a fifth resistor R5 and a capacitor unit 401, wherein the fifth resistor R5 and the capacitor unit 401 are connected in series between the first end of the fourth switch tube Q4 and the second end of the third switch tube Q3.

[0074] It should be noted that the fifth resistor R5 is used to provide a driving current to the first terminal of the fourth switch tube Q4. For example, when the fourth switch tube Q4 is a transistor, the fifth resistor R5 can serve as a base resistor of the fourth switch tube Q4, and is used to inject current, i.e., bias current, into the base of the fourth switch tube Q4.

[0075] Taking the example of a first switch Q1 being a MOS transistor, a third switch Q3 being a transistor, and a fourth switch Q4 being a transistor, as the first switch Q1 discharges, the voltage Vgs between the first terminal of the first switch Q1 and the second terminal of the first switch Q1 gradually decreases, causing the impedance Rds between the third terminal of the first switch Q1 and the second terminal of the first switch Q1 to increase. Accordingly, the voltage Vds between the third terminal of the first switch Q1 and the second terminal of the first switch Q1 gradually increases. It should be noted that the Vgs of a MOS transistor is generally around 3V. As Vgs gradually decreases, the impedance Rds increases rapidly, generally from the milli-ohm level to the ohm level.

[0076] The fourth switch tube Q4 includes a body diode. When the voltage Vds between the third terminal of the first switch tube Q1 and the second terminal of the first switch tube Q1 gradually increases to the conduction voltage Vbe2 of the body diode of the fourth switch tube Q4 (typically 0.7V), the first terminal of the fourth switch tube Q4 and the second terminal of the fourth switch tube Q4 are connected, and the battery charges the capacitor unit 401, thereby generating a driving current.

[0077] The drive current drives the fourth switch tube Q4 to turn on, and the drive current further flows to the first end of the third switch tube Q3 through the fourth resistor R4. When the voltage between the first end of the third switch tube Q3 and the second end of the third switch tube Q3 reaches the turn-on voltage Vbe1 of the third switch tube Q3, the third switch tube Q3 is turned on. At this time, the charge between the first end of the first switch tube Q1 and the second end of the first switch tube Q1 is further discharged or bleeded through the first resistor R1, the third resistor R3, and the third switch tube Q3, further improving the turn-off speed of the first switch tube Q1.

[0078] In addition, when the charge between the first terminal of the first switch tube Q1 and the second terminal of the first switch tube Q1 is discharged or released through the first resistor R1, the third resistor R3, and the third switch tube Q3, the Vds of the first switch tube Q1 is increased (the on-resistance Ron is increased), so that the drive current of the third switch tube Q3 is increased, and the third switch tube Q3 is maintained in saturation conduction until the Vds of the first switch tube Q1 stops increasing and the Vds voltage of the first switch tube Q1 drops to 0V, thereby ensuring that the first switch tube Q1 is completely turned off, thereby ensuring circuit safety.

[0079] Optionally, the capacitor unit 401 may include a first capacitor C1 and a second capacitor C2. The function of the first capacitor C1 and the second capacitor C2 is to provide a driving current to the fourth switch tube Q4 to turn on the fourth switch tube Q4. At the same time, when the first switch tube Q1 is completely turned off, the first capacitor C1 and the second capacitor C2 are fully charged, which is equivalent to disconnecting the loop where the fourth switch tube Q4, the fifth resistor R5, the first capacitor C1 and the second capacitor C2 are located, thereby reducing power consumption and ensuring that there is no leakage at the P+ port.

[0080] It can be understood that after the second switch tube Q2 is turned on, as the Vgs of the first switch tube Q1 decreases, the Vds of the first switch tube Q1 gradually increases. When the Vds of the first switch tube Q1 is greater than the turn-on voltage Vbe2 of the fourth switch tube Q4, the first capacitor C1 and the second capacitor C2 are charged through the fourth switch tube Q4 and the fifth resistor R5. The instantaneous emitter current of the fourth switch tube Q4 is large, and the fourth switch tube Q4 is saturated and turned on. The positive electrode B+total voltage of the battery directly drives the third switch tube Q3 to turn on. The charge between the first and second terminals of the first switch tube Q1 is quickly discharged through the first resistor R1, the third resistor R3, and the third switch tube Q3, thereby quickly turning off the first switch tube Q1.

[0081] Optionally, the switching circuit may further include a first diode D1, with an anode of the first diode D1 electrically connected to the first terminal of the fourth switching transistor Q4, and a cathode of the first diode D1 electrically connected to the third terminal of the first switching transistor Q1 and the second terminal of the fourth switching transistor Q4, respectively. The function of the first diode D1 is to provide a discharge circuit for the first capacitor C1 and the second capacitor C2, while ensuring that the fourth switching transistor Q4 does not suffer reverse breakdown during the discharge of the first capacitor C1 and the second capacitor C2.

[0082] See also Figure 5 , Figure 5 This is a schematic diagram of the circuit structure of the switching circuit provided in an embodiment of the present application in the fourth scenario. Figure 5 In the embodiment, the discharge module 102 may further include a three-stage discharge circuit 203 , through which the first switch tube Q1 may be discharged, that is, the charge between the first end of the first switch tube Q1 and the second end of the first switch tube Q1 may be discharged through the three-stage discharge circuit 203 .

[0083] The three-stage discharge circuit 203 may include a first resistor R1 and a sixth resistor R6, wherein the first resistor R1 and the sixth resistor R6 are connected in series between a first end of the first switching transistor Q1 and a second end of the first switching transistor Q1. Specifically, the first end of the first resistor R1 is electrically connected to the first end of the first switching transistor Q1, the first end of the sixth resistor R6 is electrically connected to the second end of the first switching transistor Q1, and the second end of the first resistor R1 is electrically connected to the second end of the sixth resistor R6.

[0084] It should be noted that the sixth resistor R6 is a discharge resistor of the first switch tube Q1, and can specifically be a pull-down resistor. When the first pin DSG outputs a first voltage signal to indicate that the first switch tube Q1 is turned off, the voltage between the first end of the first switch tube Q1 and the second end of the first switch tube Q1 can be fixed at a low level, making the level more stable, and avoiding circuit instability caused by voltage suspension.

[0085] It can be understood that when the first switch tube Q1 is turned off, it can be discharged through the first resistor R1 and the sixth resistor R6. That is, the charge between the first end of the first switch tube Q1 and the second end of the first switch tube Q1 can be discharged through the first resistor R1 and the sixth resistor R6, so as to further improve the turn-off speed of the first switch tube Q1.

[0086] Optionally, the switching circuit further includes a second diode D2, the anode of the second diode D2 being electrically connected to the first pin DSG, and the cathode of the second diode D2 being electrically connected to the first end of the first switching tube Q1. The second diode D2 is an anti-reverse diode, which has an anti-reverse function, and can prevent the high voltage pulse of P+ from directly impacting the first pin DSG when it comes in, so that the first pin DSG has sufficient high voltage pulse protection capability. The switching circuit not only has the function of quickly shutting off the first switching tube Q1, but also has a high voltage pulse protection function. Since there are no special requirements for the control module 101 itself, the embodiment of the present application can improve the safety and reliability of the switching circuit at a low cost, and can ensure the safe and reliable operation of the battery management system, as well as the safe and efficient operation of the battery system.

[0087] Optionally, the switching circuit may further include a seventh resistor R7 and an eighth resistor R8, the first end of the seventh resistor R7 being electrically connected to the first pin DSG, the second end of the seventh resistor R7 being electrically connected to the anode of the second diode D2, the first end of the second switch tube Q2, and the first end of the eighth resistor R8, respectively, and the second end of the eighth resistor R8 being electrically connected to the second end of the first switch tube Q1.

[0088] Among them, the seventh resistor R7 and the eighth resistor R8 serve as discharge resistors of the second switch tube Q2. The seventh resistor R7 can also serve as a current limiting resistor to limit the current of the branch in which it is located to prevent the first pin DSG from outputting an instantaneous current that is too large, causing the output of the first pin DSG to exceed the rated current.

[0089] In the embodiment of the present application, the first switching transistor Q1 may be a power MOS transistor connected to the positive electrode B+ (the total positive terminal of the battery). Generally, the parasitic capacitance Cgs between the gate and source of a single MOS transistor is ≈7 nF. To increase the overcurrent capability and reduce the temperature rise of the power MOS transistor, multiple power MOS transistors are usually connected in parallel. In this case, the capacitance Cgs is relatively large. When the power MOS transistor is turned on, the size of the seventh resistor R7 affects the turn-on time of the power MOS transistor. Therefore, the resistance values ​​of the first resistor R1 and the seventh resistor R7 cannot be too large. For example, the sum of the resistance values ​​of R1 and R7 can be limited to be less than or equal to a preset resistance threshold. For example, if the preset resistance threshold is 1 kΩ, then R1 + R7 ≤ 1 kΩ, and so on. The resistance values ​​of the first resistor R1 and the seventh resistor R7 can be adjusted accordingly according to specific application scenarios or specific needs, and are not particularly limited in the embodiment of the present application.

[0090] Taking the second switch Q2 as a MOS transistor as an example, when the first pin DSG outputs the first voltage signal, the first switch Q1 begins to turn off, and the voltage at the gate of the second switch Q2 is discharged through the seventh resistor R7 and the eighth resistor R8. The voltage drop between the source and the gate of the second switch Q2 is greater than or equal to the threshold voltage Vgs(th) between the gate and the source when the second switch Q2 begins to turn on. The second switch Q2 is saturated and turned on, and the voltage between the first terminal and the second terminal of the first switch Q1 drops rapidly, thereby further improving the turn-off speed of the first switch Q1.

[0091] It should be noted that the eighth resistor R8 can be a relatively large resistor, such as a KΩ or MΩ resistor. The eighth resistor R8 can also serve as a pull-down resistor for the first terminal of the second switch Q2. When the first pin DSG outputs the first voltage signal that turns off the first switch Q1, the eighth resistor R8 pulls the potential of the first terminal of the second switch Q2 down to the potential of the P+ port, thereby preventing the second switch Q2 from being mistakenly turned on.

[0092] Optionally, the switching circuit further includes a voltage regulator tube ZD1 , which is a Vgs protection voltage regulator tube of the first switching tube Q1 , and is used to prevent the Vgs of the first switching tube Q1 from exceeding a rated voltage, thereby damaging the first switching tube Q1 .

[0093] The present application also provides a battery management system. Figure 6 , Figure 6is a schematic diagram of the structure of a battery management system provided in an embodiment of the present application. The battery management system 500 includes a controller 501 and a switch circuit 502 provided in an embodiment of the present application. The switch circuit 502 includes a control module 503. The controller 501 is electrically connected to the control module 503. The control module 503 receives a first signal from the controller 501. The first signal is configured to instruct the control module 503 to output a first voltage signal, such as a low voltage signal, which instructs the first switch in the switch circuit 502 to turn off.

[0094] The present application also provides a battery pack. Figure 7 , Figure 7 6 is a schematic diagram of the structure of a battery pack provided in an embodiment of the present application. The battery pack 600 includes a battery cell module 601 and a battery management system 602 provided in an embodiment of the present application. The battery cell module 601 includes at least one battery cell, that is, the battery cell module 601 may include one or more battery cells. The battery cell module 601 is electrically connected to the battery management system 602, and the battery cell module 601 is used to power the battery management system 602 to enable the battery management system 602 to operate normally.

[0095] The present application also provides an electrical device. Figure 8 , Figure 8 Schematic diagram of the structure of the electric device provided in the embodiment of the present application. The electric device 700 includes a load 701 and a battery pack 702 provided in the embodiment of the present application. The battery pack 702 is electrically connected to the load 701 and is used to power the load 701 so that the load 701 can operate normally.

[0096] exist Figures 2 to 5 Based on the switching circuit described below Figure 9 and Figure 10 As an example, a switch circuit control method according to an embodiment of the present application is described. The switch circuit control method is used to control the switch circuit provided by the embodiment of the present application.

[0097] See also Figure 9 , Figure 9 A flow chart of a switch circuit control method provided in an embodiment of the present application. The switch circuit control method may include:

[0098] S11 , when the first pin outputs a first voltage signal, controlling the second switch tube to be turned on, and discharging the charge between the first end of the first switch tube and the second end of the first switch tube through a primary discharge circuit.

[0099] When the first pin of the control module outputs a first voltage signal, such as a low voltage signal of approximately 0V, the second switch is controlled to conduct, and the charge between the first terminal of the first switch and the second terminal of the first switch is discharged through a primary discharge circuit, such as through the second switch, thereby increasing the turn-off speed of the first switch. It is understood that when the first switch is turned off, the primary discharge circuit discharges the first switch, achieving rapid discharge of the charge, thereby increasing the turn-off speed of the first switch. Therefore, the present application can quickly turn off the switch.

[0100] See also Figure 10 , Figure 10 Another flow chart of a switch circuit control method provided in an embodiment of the present application. The switch circuit control method may include:

[0101] S21 . When the first pin outputs a first voltage signal, the second switch tube is controlled to be turned on, and the charge between the first end of the first switch tube and the second end of the first switch tube is discharged through a primary discharge circuit.

[0102] The specific implementation of S21 can refer to the implementation of S11, which will not be repeated here.

[0103] S22: When the voltage between the third terminal of the first switch tube and the second terminal of the first switch tube is greater than or equal to the first threshold voltage, the third switch tube and the fourth switch tube are controlled to be turned on, and the charge between the first terminal of the first switch tube and the second terminal of the first switch tube is also discharged through the secondary discharge circuit.

[0104] When the voltage between the third terminal of the first switch and the second terminal of the first switch is greater than or equal to a first threshold voltage, the fourth switch is turned on, thereby further turning on the third switch. The charge between the first terminal of the first switch and the second terminal of the first switch is also discharged through the secondary discharge circuit, further accelerating the discharge of the charge, thereby further improving the turn-off speed of the first switch. It should be noted that the first threshold voltage may be the turn-on voltage of the fourth switch. When the fourth switch is a transistor, the turn-on voltage of the fourth switch is the turn-on voltage between the base and emitter of the transistor, which is generally 0.7V.

[0105] S23: When the third switch tube is turned on, the charging module is in a charging state, and when the charge between the first end of the first switch tube and the second end of the first switch tube is released, the charging module stops charging.

[0106] When the third switch is on, the charging module is in a charging state. When the charge between the first terminal of the first switch and the second terminal of the first switch is completely released and the first switch is completely turned off, the charging module stops charging. By completely turning off the first switch, circuit safety can be enhanced.

[0107] Although the present application has been shown and described with respect to one or more implementations, equivalent variations and modifications will occur to those skilled in the art based on reading and understanding this specification and the accompanying drawings. The present application includes all such modifications and variations and is limited only by the scope of the appended claims. In particular, with respect to the various functions performed by the above-mentioned components, the terms used to describe such components are intended to correspond to any component (unless otherwise indicated) that performs the specified function of the component (e.g., it is functionally equivalent), even if it is not structurally equivalent to the disclosed structure that performs the function in the exemplary implementation of this specification shown herein.

[0108] That is, the above description is merely an embodiment of the present application and does not limit the patent scope of the present application. Any equivalent structural or equivalent process transformations made using the contents of the description and drawings of this application, such as the mutual combination of technical features between the various embodiments, or direct or indirect application in other related technical fields, are also included in the patent protection scope of the present application.

[0109] In addition, in the description of the present application, it should be understood that the orientation or positional relationship indicated by the term "inside" and the like is based on the orientation or positional relationship shown in the accompanying drawings, and is only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present application. In addition, for structural elements with the same or similar characteristics, the present application may use the same or different reference numerals for identification. In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more features. In the description of the present application, the meaning of "multiple" is two or more, unless otherwise clearly and specifically defined.

[0110] In this application, the word "exemplary" is used to mean "serving as an example, illustration or description". Any embodiment described in this application as "exemplary" is not necessarily to be construed as being more preferred or more advantageous than other embodiments. The above description is provided to enable any person skilled in the art to implement and use the present application. In the above description, various details are listed for the purpose of explanation. It should be understood that a person of ordinary skill in the art can recognize that the present application can be implemented without using these specific details. In other embodiments, well-known structures and processes will not be elaborated in detail to avoid obscuring the description of the present application with unnecessary details. Therefore, the present application is not intended to be limited to the embodiments shown, but is consistent with the widest scope consistent with the principles and features disclosed in this application.

Claims

1. A switch circuit, comprising a first switch tube, a control module and a discharge module, characterized in that: The first switch tube is arranged in the main circuit loop and is electrically connected to the control module and the discharge module respectively; The control module comprises a first pin, and the control module is configured to output a voltage signal through the first pin, wherein the voltage signal is used to indicate whether the first switch tube is turned on or off; Wherein, the voltage signal includes a first voltage signal, the first voltage signal is used to instruct the first switch tube to turn off, and when the first pin outputs the first voltage signal, the first switch tube discharges through the discharge module; The discharge module includes a primary discharge loop and a secondary discharge loop, wherein two ends of the primary discharge loop are electrically connected to a first end of the first switch tube and a second end of the first switch tube, respectively, the first end of the first switch tube is also electrically connected to the first pin for receiving the voltage signal, and the third end of the first switch tube is electrically connected to a first end of a battery; and two ends of the secondary discharge loop are electrically connected to a first end of the first switch tube and a second end of the first switch tube, respectively; Wherein, the primary discharge circuit includes a second switch tube, the second switch tube is electrically connected to the first pin and is used to receive the voltage signal, and when the second switch tube is turned on, the first switch tube discharges through the primary discharge circuit; Among them, the secondary discharge circuit includes a third switch tube, a fourth switch tube and a fourth resistor, the first end of the third switch tube is electrically connected to the third end of the first switch tube, the second end of the third switch tube is electrically connected to the second end of the first switch tube, and when the third switch tube is turned on, the first switch tube also discharges through the secondary discharge circuit; the fourth switch tube and the fourth resistor are connected in series between the third end of the first switch tube and the first end of the third switch tube.

2. The switch circuit according to claim 1, characterized in that: The primary discharge loop further includes a first resistor and a second resistor, wherein the first resistor, the second resistor and the second switch tube are connected in series between a first end of the first switch tube and a second end of the first switch tube.

3. The switch circuit according to claim 1, characterized in that: The secondary discharge loop further includes a first resistor and a third resistor, and the first resistor, the third resistor and the third switch tube are connected in series between a first end of the first switch tube and a second end of the first switch tube.

4. The switch circuit according to claim 1, characterized in that: Also includes a charging module, the charging module includes a fifth resistor and a capacitor unit; The fifth resistor and the capacitor unit are connected in series between the first end of the fourth switch tube and the second end of the third switch tube.

5. The switch circuit according to claim 4, characterized in that: It also includes a first diode, an anode of the first diode is electrically connected to the first end of the fourth switch tube, and a cathode of the first diode is electrically connected to the third end of the first switch tube and the second end of the fourth switch tube respectively.

6. The switch circuit according to claim 1, characterized in that: The discharge module further includes a three-stage discharge circuit, and the three-stage discharge circuit includes a first resistor and a sixth resistor; The first resistor and the sixth resistor are connected in series between the first end of the first switch tube and the second end of the first switch tube, and the first switch tube discharges through the three-stage discharge loop.

7. The switch circuit according to any one of claims 2 to 6, characterized in that: It also includes a second diode, wherein an anode of the second diode is electrically connected to the first pin, and a cathode of the second diode is electrically connected to the first end of the first switch tube.

8. The switch circuit according to claim 7, characterized in that: It also includes a seventh resistor and an eighth resistor, wherein the first end of the seventh resistor is electrically connected to the first pin, the second end of the seventh resistor is electrically connected to the anode of the second diode, the first end of the second switch tube and the first end of the eighth resistor respectively, and the second end of the eighth resistor is electrically connected to the second end of the first switch tube.

9. A battery management system, characterized in that: The battery management system comprises: a controller, and a switch circuit as claimed in any one of claims 1 to 8; The controller is electrically connected to the control module, and the control module obtains a first signal from the controller, and the first signal is configured to instruct the control module to output a first voltage signal.

10. A battery pack, characterized in that: The battery pack comprises: a battery cell module, and a battery management system as claimed in claim 9; Among them, the battery cell module includes at least one battery cell, the battery cell module is electrically connected to the battery management system, and the battery cell module is used to supply power to the battery management system.

11. An electrical device, characterized in that: The electrical equipment comprises: a load, and a battery pack as claimed in claim 10, wherein the battery pack is electrically connected to the load, and the battery pack is used to supply power to the load.

12. A switch circuit control method, characterized in that: The control method is used to control the switch circuit according to claim 4, and the control method comprises: When the first pin outputs the first voltage signal, the second switch tube is controlled to be turned on, and the charge between the first end of the first switch tube and the second end of the first switch tube is discharged through the primary discharge loop.

13. The switch circuit control method according to claim 12, characterized in that: When the voltage between the third end of the first switch tube and the second end of the first switch tube is greater than or equal to the first threshold voltage, the third switch tube and the fourth switch tube are controlled to be turned on, and the charge between the first end of the first switch tube and the second end of the first switch tube is also discharged through the secondary discharge circuit.

14. The switch circuit control method according to claim 13, characterized in that: When the third switch tube is turned on, the charging module is in a charging state, and when the charge between the first end of the first switch tube and the second end of the first switch tube is released, the charging module stops charging.

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