CN115133626A - Battery protection circuit, control method thereof and battery management system - Google Patents

Abstract

The embodiments of the present invention disclose a battery protection circuit, a control method thereof, and a battery management system. The battery protection circuit includes a switch module, a fusing module and a first detection module; the switch module, the fusing module and the battery pack are connected in series between the first power supply terminal and the second power supply terminal; the switch module is arranged close to the second power supply terminal, and the switch module is used for In response to the signal of its own control terminal, it is turned on or off to control the charging and discharging of the battery pack; the fusing module is used to disconnect in response to the signal of its own control terminal; the first detection module is used to obtain the signal of the second power supply terminal and the control terminal of the switch module, The conduction state of the switch module is determined according to the signal of the second power supply terminal, and the fuse module is controlled to be disconnected when the signal of the control terminal of the switch module is an off-level signal and the switch module is in the conduction state. The technical solutions of the embodiments of the present invention help to enhance the safety and reliability of the battery pack and the battery protection circuit.

Description

Battery protection circuit and its control method and battery management system

technical field

The embodiments of the present invention relate to the technical field of batteries, and in particular, to a battery protection circuit, a control method thereof, and a battery management system.

Background technique

The existing battery management system (Battery Management System, BMS) generally includes a battery pack and its protection circuit. The battery pack protection circuit includes a fuse device connected in series with the battery pack. The battery pack protection circuit can be based on the voltage and current of the battery pack. Parameters, etc. control whether the fuse device is disconnected, so as to improve the safety and reliability of the battery management system BMS.

However, when the BMS of the battery management system is impacted by an external signal, the protection circuit of the battery pack is often abnormal, so that it cannot accurately control the disconnection of the fuse device, which is likely to cause safety accidents.

SUMMARY OF THE INVENTION

The embodiments of the present invention provide a battery protection circuit, a control method thereof, and a battery management system, so as to trigger the normal start of the fuse module when the battery pack and the battery protection circuit are impacted by external signals, so as to achieve the protection effect in an abnormal state, Thus, the safety and reliability of the battery pack and the battery protection circuit are enhanced.

In a first aspect, an embodiment of the present invention provides a battery protection circuit, including:

A switch module and a fuse module, the switch module, the fuse module and the battery pack are connected in series between the first power supply terminal and the second power supply terminal; the switch module is arranged close to the second power supply terminal, and the switch module is used for It is turned on or off in response to the signal of its own control end to control the charging and discharging of the battery pack; the fuse module is used to disconnect in response to the signal of its own control end;

The first detection module is connected to the second power supply terminal, the control terminal of the switch module and the control terminal of the fuse module, and is used for acquiring the signals of the second power supply terminal and the control terminal of the switch module, according to the The signal of the second power supply terminal determines the conduction state of the switch module, and controls the fuse module to disconnect when the signal of the control terminal of the switch module is an off-level signal and the switch module is in the conduction state.

Optionally, the fuse module includes a first switch and a fuse device;

The control end of the first switch serves as the control end of the fuse module, the first end of the first switch is connected to the control end of the fuse device, the second end of the first switch is grounded, and the fuse device connected in series with the switch module and the battery pack;

The first switch is configured to be turned on or off according to a signal of its own control terminal, so as to control the fuse device to be turned off when turned on;

The fuse device includes a three-terminal fuse.

Optionally, the battery protection circuit further includes a control module, the control module is connected to the battery pack, the control terminal of the switch module and the control terminal of the fuse module, and is used for monitoring the switch module and the fuse module. The fuse module is controlled;

The switch module includes a first transistor and a second transistor, the first transistor and the second transistor are connected in series between the first power supply terminal and the second power supply terminal, the first transistor and/or The gate of the second transistor serves as the control terminal of the switch module.

Optionally, the first detection module includes a first detection unit, a second detection unit, a third detection unit and an AND gate circuit;

The input end of the first detection unit is connected to the control end of the switch module, the output end of the first detection unit is connected to the first input end of the AND gate circuit, and the first detection unit is used for The first level signal is output when the signal of the control terminal of the switch module is the off-level signal, and the second level signal is output when the signal of the control terminal of the switch module is the on-level signal;

The input end of the second detection unit is connected to the second power supply end, the output end of the second detection unit is connected to the second input end of the AND gate circuit, and the first electrode of the battery pack is connected to the first electrode. A power supply terminal, the switch module is connected between the second electrode of the battery pack and the second power supply terminal, a load is connected between the first power supply terminal and the second power supply terminal, and the first power supply terminal is connected to the second power supply terminal. The second detection unit is configured to output the first level signal when the signal at the second power supply terminal is the second electrode signal of the battery pack, and the signal at the second power supply terminal is the first electrode of the battery pack outputting the second level signal when the signal is present;

The input end of the third detection unit is connected between the battery pack and the switch module, the output end of the third detection unit is connected to the third input end of the AND gate circuit, and the third detection unit for outputting the first level signal when the current between the battery pack and the switch module is greater than or equal to a set current, and the current between the battery pack and the switch module is less than the set current outputting the second level signal when the current is constant;

The output end of the AND gate circuit is connected to the control end of the fuse module, and the AND gate circuit is used for the signals at its first input end, the second input end and the third input end to be the first level When the signal is received, the first level signal is output to the control terminal of the fuse module to control the fuse module to disconnect.

Optionally, the first detection unit includes a first diode, a first resistor and a second switch, an anode of the first diode is connected to a control terminal of the switch module, and the first diode The cathode of the second switch is connected to the control terminal of the second switch, the first terminal of the second switch is connected to the power terminal through the first resistor, and the second terminal of the second switch is grounded;

The second detection unit includes a second diode, a second resistor and a third switch, the anode of the second diode is connected to the second power supply terminal, and the cathode of the second diode is connected to the the control terminal of the third switch, the first terminal of the third switch is connected to the power terminal through the second resistor, and the second terminal of the third switch is grounded;

The third detection unit includes a first comparator, a third resistor, a fourth resistor and a fifth resistor, a first end of the third resistor is connected to a reference voltage end, and a second end of the third resistor is connected to the The first end of the fourth resistor, the second end of the fourth resistor are grounded, the first comparison signal input end of the first comparator is connected to the second end of the third resistor, the battery pack and the A sixth resistor is connected in series between the switch modules, the second comparison signal input terminal of the first comparator is connected to the sixth resistor, and the output terminal of the first comparator is connected to the power supply terminal through the fifth resistor;

The AND gate circuit includes a third diode, a fourth diode, a fifth diode and a seventh resistor, the first end of the seventh resistor is connected to the power supply end, and the cathode of the third diode connected to the first end of the second switch, the cathode of the fourth diode is connected to the first end of the third switch, and the cathode of the fifth diode is connected to the output end of the first comparator , the anode of the third diode, the anode of the fourth diode and the anode of the fifth diode are connected to the second end of the seventh resistor, and the second end of the seventh resistor Connect to the control terminal of the fuse module.

Optionally, the battery protection circuit further includes a delay module and a second detection module;

The delay module is connected between the first detection module and the control terminal of the fuse module, and is used for delaying the output of the output signal of the first detection module to the control terminal of the fuse module;

The second detection module is connected to the delay module, and the second detection module is used to detect the temperature of the switch module, and control the delay module when the temperature of the switch module is greater than or equal to a set temperature The delay time is shortened.

Optionally, the delay module includes an eighth resistor and a first capacitor, the eighth resistor is connected between the first detection module and the control terminal of the fuse module, the first capacitor of the first capacitor is The pole is connected between the eighth resistor and the control terminal of the fuse module, and the second pole of the first capacitor is grounded;

The second detection module includes a ninth resistor, a tenth resistor, an eleventh resistor, a thermistor, an optocoupler device, a second comparator and a fourth switch, and the first end of the ninth resistor is connected to the power supply end, The second end of the ninth resistor is connected to the first end of the thermistor, the second end of the thermistor is grounded, and the first comparison signal input end of the second comparator is connected to the reference voltage, so The second comparison signal input end of the second comparator is connected to the second end of the ninth resistor, and the tenth resistor is connected between the output end of the second comparator and the second comparison signal input end, so The eleventh resistor is connected between the output end of the second comparator and the power supply end, the output end of the second comparator is connected to the control end of the fourth switch, and the first input of the optocoupler device The terminal is connected to the power terminal, the first output terminal of the optocoupler device is connected to the first terminal of the fourth switch, the second terminal of the fourth switch is grounded, and the second input terminal of the optocoupler device is connected to the The first end of the eighth resistor, and the second output end of the optocoupler device is connected to the second end of the eighth resistor.

In a second aspect, an embodiment of the present invention provides a method for controlling a battery protection circuit, where the battery protection circuit includes: a switch module, a fuse module, and a first detection module; the switch module, the fuse module and the battery pack are connected between the first power supply terminal and the second power supply terminal; the switch module is arranged close to the second power supply terminal, and the switch module is used to turn on or off in response to a signal from its own control terminal to control the battery pack charging and discharging; the fuse module is used to disconnect in response to a signal from its own control terminal; the first detection module is connected to the second power terminal, the control terminal of the switch module and the control terminal of the fuse module;

The control method of the battery protection circuit includes:

Acquire the signals of the second power supply terminal and the control terminal of the switch module through the first detection module;

Determine the conduction state of the switch module by the first detection module according to the signal of the second power supply terminal;

The fuse module is controlled to be disconnected by the first detection module when the signal at the control end of the switch module is an off-level signal and the switch module is in an on state.

Optionally, the battery protection circuit further includes a delay module and a second detection module; the delay module is connected between the first detection module and the control terminal of the fuse module, and the second detection module connecting the delay module;

The control method of the battery protection circuit also includes:

Delay outputting the output signal of the first detection module to the control terminal of the fuse module through the delay module;

The temperature of the switch module is detected by the second detection module, and when the temperature of the switch module is greater than or equal to a set temperature, the delay time of the delay module is controlled to shorten.

In a third aspect, embodiments of the present invention provide a battery management system, including a battery pack and the battery protection circuit described in the first aspect, or a control method using the battery protection circuit described in the second aspect.

In the battery protection circuit and the control method and the battery management system provided by the embodiments of the present invention, the signals of the second power supply terminal and the control terminal of the switch module are obtained through the first detection module, and the conduction state of the switch module is determined according to the signal of the second power supply terminal, When the signal at the control end of the switch module is the off-level signal and the switch module is in the on state, it is determined that the switch module is broken down and damaged, so that the first detection module controls the fuse module to disconnect, so as to realize the protection circuit between the battery pack and the battery. The fuse module is triggered to start normally under the impact of external signals, so as to achieve the protection effect under abnormal conditions, which helps to enhance the safety and reliability of the battery pack and the battery protection circuit.

It should be understood that the content described in this section is not intended to identify key or critical features of the embodiments of the invention, nor is it intended to limit the scope of the invention. Other features of the present invention will become readily understood from the following description.

Description of drawings

In order to illustrate the technical solutions in the embodiments of the present invention more clearly, the following briefly introduces the accompanying drawings used in the description of the embodiments. Obviously, the accompanying drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can also be obtained from these drawings without creative effort.

1 is a schematic structural diagram of a battery protection circuit provided by an embodiment of the present invention;

2 is a schematic structural diagram of another battery protection circuit provided by an embodiment of the present invention;

3 is a schematic structural diagram of a first detection module provided by an embodiment of the present invention;

4 is a schematic structural diagram of a first detection module, a delay module, and a second detection module provided by an embodiment of the present invention;

FIG. 5 is a schematic flowchart of a control method of a battery protection circuit further provided by an embodiment of the present invention.

Detailed ways

In order to make those skilled in the art better understand the solutions of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only Embodiments are part of the present invention, but not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

It should be noted that the terms "first", "second" and the like in the description and claims of the present invention and the above drawings are used to distinguish similar objects, and are not necessarily used to describe a specific sequence or sequence. It is to be understood that the data so used may be interchanged under appropriate circumstances such that the embodiments of the invention described herein can be practiced in sequences other than those illustrated or described herein. Furthermore, the terms "comprising" and "having" and any variations thereof, are intended to cover non-exclusive inclusion, for example, a process, method, system, product or device comprising a series of steps or units is not necessarily limited to those expressly listed Rather, those steps or units may include other steps or units not expressly listed or inherent to these processes, methods, products or devices.

Embodiments of the present invention provide a battery protection circuit. FIG. 1 is a schematic structural diagram of a battery protection circuit provided by an embodiment of the present invention. Referring to FIG. 1 , the battery protection circuit includes a switch module 10 , a fusing module 20 and a first detection module 40 .

The switch module 10, the fuse module 20 and the battery pack 30 are connected in series between the first power supply terminal V1 and the second power supply terminal V2. The switch module 10 is disposed close to the second power terminal V2 , and the switch module 10 is used to turn on or off in response to a signal from its own control terminal to control the charging and discharging of the battery pack 30 . The fuse module 20 is used for disconnecting in response to a signal from its own control terminal.

The first detection module 40 is connected to the second power terminal V2, the control terminal of the switch module 10 and the control terminal of the fuse module 20, and is used to obtain the signals of the second power terminal V2 and the control terminal of the switch module 10, according to the signal of the second power terminal V2. The signal determines the on state of the switch module 10, and controls the fuse module 20 to disconnect when the signal at the control end of the switch module 10 is an off level signal and the switch module 10 is in the on state.

Specifically, the battery pack 30 may be a lithium-ion power battery, for example, the battery pack 30 may be a battery pack in a battery management system BMS. The battery pack 30 is connected in series between the first power supply terminal V1 and the second power supply terminal V2, and a load can also be connected between the first power supply terminal V1 and the second power supply terminal V2 to discharge the load through the battery pack 30, and the first power supply terminal The V1 and the second power terminal V2 can also be respectively connected to power sources to charge the battery pack 30 . Either the switch module 10 and the fuse module 20 can be connected in series between the first power terminal V1 and the first electrode of the battery pack 30 , or can also be connected in series between the second power terminal V2 and the battery pack 30 . between the second electrodes. When the first electrode of the battery pack 30 is the positive electrode and the second electrode of the battery pack 30 is the negative electrode, the first power supply terminal V1 is used as the power supply positive electrode, and the second power supply terminal V2 is used as the power supply negative electrode; when the first electrode of the battery pack 30 is the negative electrode , when the second electrode of the battery pack 30 is the positive electrode, the first power supply terminal V1 is used as the negative electrode of the power supply, and the second power supply terminal V2 is used as the positive electrode of the power supply. The switch module 10 is disposed close to the second power terminal V2 , which means that the switch module 10 is connected in series between the second power terminal V2 and the second electrode of the battery pack 30 . In each embodiment of the present invention, the case where the fuse module 20 is connected in series between the second power supply terminal V2 and the second electrode of the battery pack 30 is taken as an example for description. In other embodiments, the fuse module 20 can also be arranged in series Connected between the first power terminal V1 and the first electrode of the battery pack 30 .

By transmitting different signals to the control terminal of the switch module 10, the switch module 10 can be controlled to be turned on or off, so as to control the conduction or disconnection between the second electrode of the battery pack 30 and the second power terminal V2, so as to control the battery Charge and discharge of group 30. The fuse module 20 can be blown when the current flowing through itself is too large. By transmitting a control signal to the control terminal of the fuse module 20 , the fuse module 20 can also be controlled to fuse to protect the battery pack 30 .

Optionally, the battery protection circuit further includes a control module 50, the control module 50 is connected to the battery pack 30, the control terminal of the switch module 10 and the control terminal of the fuse module 20, and the control module 50 can transmit a signal to the control terminal of the switch module 10 to The switch module 10 is controlled to be turned on or off, so as to control the charging and discharging of the battery pack 30 . The control module 50 can also transmit a signal to the control terminal of the fuse module 20 to control the fuse module 20. For example, the control module 50 can obtain the cell voltage of the battery pack 30 when charging, and when the cell voltage of the battery pack 30 exceeds the When the voltage threshold is reached, a signal is transmitted to the control terminal of the fuse module 20 to trigger the fuse module 20 to fuse and stop the charging process of the battery pack 30 to protect the battery pack 30 .

The signal of the control terminal of the switch module 10 is an on-level signal or an off-level signal. The on-level signal refers to a signal that controls the switch module 10 to be turned on, and the off-level signal refers to a signal that controls the switch module 10 to be turned off. The first detection module 40 can determine that the signal of the control end of the switch module 10 is an on-level signal or an off-level signal by acquiring the signal of the control end of the switch module 10 . The first detection module 40 can determine the conduction state between the battery pack 30 and the second power supply terminal V2 by acquiring the signal of the second power supply terminal V2, thereby determining the conduction state of the switch module 10, for example, when the fuse module 20 does not occur In the case of fuse, if the first detection module 40 determines that the battery pack 30 is connected to the second power supply terminal V2 according to the signal of the second power supply terminal V2, it can be further determined that the switch module 10 is in the conduction state. If the module 40 determines that the battery pack 30 is disconnected from the second power supply terminal V2 according to the signal of the second power supply terminal V2, it can be further determined that the switch module 10 is in an off state. When the battery pack 30 is being charged/discharged, if the first detection module 40 determines that the signal of the control terminal of the switch module 10 is the off-level signal according to the signal of the second power supply terminal V2 and the control terminal of the switch module 10 and the switch module 10 is in On state, it indicates that the switch module 10 is damaged such as breakdown. For example, the battery pack 30 and the battery protection circuit may be impacted by external signals at this time, causing the switch module 10 to break down. Therefore, the first detection module 40 can be blown to the fuse. The control terminal of the module 20 transmits a control signal to control the fusing of the fuse module 20 to protect the battery pack 30 .

The technical solution of the embodiment of the present invention is to obtain the signals of the second power supply terminal and the control terminal of the switch module through the first detection module, determine the conduction state of the switch module according to the signal of the second power supply terminal, and take the signal at the control terminal of the switch module as the off state. When the level signal is off and the switch module is in the on state, it is determined that the switch module is broken down and damaged, so that the first detection module controls the fuse module to disconnect, so as to trigger the fuse module when the battery pack and battery protection circuit are impacted by external signals. Normal start, to achieve protection in abnormal state, help to enhance the safety and reliability of the battery pack and battery protection circuit.

FIG. 2 is a schematic structural diagram of another battery protection circuit provided by an embodiment of the present invention. Referring to FIG. 2 , on the basis of the foregoing embodiment, optionally, the fusing module 20 includes a first switch K1 and a fusing device 210 . The control terminal of the first switch K1 serves as the control terminal of the fuse module 20, the first terminal of the first switch K1 is connected to the control terminal of the fuse device 210, the second terminal of the first switch K1 is grounded, the fuse device 210 is connected to the switch module 10 and the battery Group 30 in series. The first switch K1 is used for turning on or off according to the signal of its own control terminal, so as to control the fuse device 210 to turn off when turned on.

Specifically, the first switch K1 may be a transistor, such as a triode or a field effect transistor. The field effect transistor includes a metal-oxide semiconductor field effect transistor (Metal-Oxide-Semiconductor Field-Effect Transistor, MOSFET), etc. Either an N-type transistor or a P-type transistor may be used. Exemplarily, in the case where the first switch K1 is a metal-oxide semiconductor field effect transistor MOSFET, the gate of the transistor is used as the control terminal, one of the source and drain is used as the first terminal, and the other is used as the control terminal. second end. The fuse device 210 may be a three-terminal fuse, the three-terminal fuse is connected in series with the switch module 10 and the battery pack 30, and the control terminal of the three-terminal fuse is connected to the first terminal of the first switch K1. By transmitting a signal to the control terminal of the first switch K1, the first switch K1 can be controlled to be turned on or off. When the first switch K1 is turned on, the control terminal of the fuse device 210 can be connected to the ground terminal to control the fuse device 210 For fusing, when the first switch K1 is turned off, the control terminal of the fusing device 210 is not connected to a signal, and the fusing device 210 remains in its original state.

Further, the switch module 10 includes a first transistor M1 and a second transistor M2, the first transistor M1 and the second transistor M2 are connected in series between the first power supply terminal V1 and the second power supply terminal V2, and the first transistor M1 and/or the first transistor M1 and/or the second power supply terminal V2 are connected in series. The gates of the two transistors M2 serve as the control terminals of the switch module 10 .

Specifically, the first transistor M1 and the second transistor M2 may both be metal-oxide semiconductor field effect transistors (MOSFETs), and by controlling the first transistor M1 to be turned on or off, the discharge process of the battery pack 30 can be controlled, and by controlling the second transistor M1 The transistor M2 is turned on or off to control the charging process of the battery pack 30 . In an embodiment, the gate of the first transistor M1 can be used as the control terminal of the switch module 10, that is, the first detection module 40 can be connected to the gate of the first transistor M1 to determine that the gate signal of the first transistor M1 is Turn on the level signal or turn off the level signal, so that the first detection module 40 determines the conduction state of the first transistor M1 according to the signal of the second power supply terminal V2, and the gate signal of the first transistor M1 is turned off When the level signal and the first transistor M1 are in a conducting state, the fuse module 20 is controlled to be disconnected. In another embodiment, the gate of the second transistor M2 can be used as the control terminal of the switch module 10, that is, the first detection module 40 can be connected to the gate of the second transistor M2 to determine the gate signal of the second transistor M2 is a turn-on level signal or a turn-off level signal, so that the first detection module 40 determines the conduction state of the second transistor M2 according to the signal of the second power supply terminal V2, and the gate signal of the second transistor M2 is turned off When the level signal is turned off and the second transistor M2 is in an on state, the fuse module 20 is controlled to be disconnected. In another embodiment, the gate of the first transistor M1 and the gate of the second transistor M2 can both serve as the control terminals of the switch module 10, that is, the first detection module 40 can be connected to the gate of the first transistor M1 and the gate of the second transistor M2 respectively. The gate of the second transistor M2 is used to determine the gate signals of the first transistor M1 and the second transistor M2, so that the first detection module 40 can determine the gate signals of the first transistor M1 and the second transistor M2 according to the signal of the second power supply terminal V2. In the on state, the fuse module 20 is controlled to be disconnected when the gate signal of the first transistor M1 is the off level signal and the first transistor M1 is in the on state, and the gate signal of the second transistor M2 is turned off The fuse module 20 is controlled to be disconnected when the level signal and the second transistor M2 is in an on state.

Continuing to refer to FIG. 2 , further, the control module 50 includes a control unit 510 , a parameter acquisition unit 520 and a driving unit 530 . The parameter collection unit 520 is connected to the battery pack 30 , the control unit 510 is connected to the parameter collection unit 520 , the drive unit 530 and the control end of the fuse module 20 respectively, and the drive unit 530 is connected to the control end of the switch module 10 . The parameter acquisition unit 520 may be a secondary protection chip, and the parameter acquisition unit 520 is used to acquire parameters of the battery pack 30 . The driving unit 530 is used to drive the switch module 10. In the case that the switch module 10 includes the first transistor M1 and the second transistor M2, the driving unit 530 may connect the gate of the first transistor M1 and the gate of the second transistor M2 , to drive the first transistor M1 and the second transistor M2, and control the turn-on and turn-off of the first transistor M1 and the second transistor M2. The control unit 510 may be a central processing unit (MCU), and the control unit 510 may control the drive unit 530 to drive the switch module 10 according to the parameters collected by the parameter collection unit 520, and control the fuse module 20 according to the parameters collected by the parameter collection unit 520, for example The parameter collection unit 520 can transmit the cell voltage of the battery pack 30 to the control unit 510, and the control unit 510 can transmit a signal to the control terminal of the fusing module 20 when the cell voltage of the battery pack 30 exceeds the voltage threshold to trigger the fusing of the fusing module 20. . In other embodiments, the cell voltage of an analog front end (Analog Front End, AFE), the gate voltages of the first transistor M1 and the second transistor M2, the first transistor M1 and the second transistor M2 may also be collected through the control unit 510 , so as to control the fuse module 20 according to the above parameters.

FIG. 3 is a schematic structural diagram of a first detection module provided by an embodiment of the present invention, and FIG. 3 shows a connection relationship among the first detection module 40 , the fusing module 20 , and the control module 50 . 2 and 3 , optionally, the first detection module 40 includes a first detection unit 410 , a second detection unit 420 , a third detection unit 430 and an AND gate circuit 440 .

The input terminal of the first detection unit 410 is connected to the control terminal of the switch module 10 , the output terminal of the first detection unit 410 is connected to the first input terminal of the AND gate circuit 440 , and the first detection unit 410 is used to control the switch module 10 . When the signal at the control terminal of the switch module 10 is an off-level signal, a first level signal is output, and when the signal at the control terminal of the switch module 10 is an on-level signal, a second level signal is output.

The input terminal of the second detection unit 420 is connected to the second power terminal V2, the output terminal of the second detection unit 420 is connected to the second input terminal of the AND gate circuit 440, the first electrode of the battery pack 30 is connected to the first power terminal V1, and the switch module 10 is connected between the second electrode of the battery pack 30 and the second power supply terminal V2, a load is connected between the first power supply terminal V1 and the second power supply terminal V2, and the second detection unit 420 is used for the second power supply terminal V2. The first level signal is output when the signal is the second electrode signal of the battery pack 30 , and the second level signal is output when the signal at the second power terminal V2 is the first electrode signal of the battery pack 30 .

The input end of the third detection unit 430 is connected between the battery pack 30 and the switch module 10 , the output end of the third detection unit 430 is connected to the third input end of the AND gate circuit 440 , and the third detection unit 430 is used to connect the battery pack 30 to the third input end of the AND gate circuit 440 . The first level signal is output when the current between the battery pack 30 and the switch module 10 is greater than or equal to the set current, and the second level signal is output when the current between the battery pack 30 and the switch module 10 is less than the set current.

The output end of the AND gate circuit 440 is connected to the control end of the fuse module 20, and the AND gate circuit 440 is used to fuse to the fuse when the signals of its first input end, the second input end and the third input end are all the first level signals. The control terminal of the module 20 outputs a first level signal to control the fuse module 20 to be disconnected.

Exemplarily, one of the on-level signal and the off-level signal of the control terminal of the switch module 10 is a high-level signal, and the other is a low-level signal. One of the first level signal and the second level signal is a high level signal, and the other is a low level signal. In this embodiment, the gate of the first transistor M1 can be set as the control terminal of the switch module 10 , and the input terminal of the first detection module 40 is connected to the gate of the first transistor M1 and connected to the gate voltage signal of the first transistor M1 Vg, the first level signal is output when the gate voltage signal Vg of the first transistor M1 is the off-level signal, and the second level signal is output when the gate voltage signal Vg of the first transistor M1 is the on-level signal flat signal.

When the first electrode of the battery pack 30 is the positive electrode and the second electrode of the battery pack 30 is the negative electrode, the first power supply terminal V1 is the power supply positive pole, and the second power supply terminal V2 is the power supply negative pole. A load is connected between the first power supply terminal V1 and the second power supply terminal V2, and when the gate voltage signals of the first transistor M1 and the second transistor M2 are both off-level signals, the first transistor M1 and the second transistor M2 The normal state is the disconnected state. If both the first transistor M1 and the second transistor M2 are in the normal state, the signal of the second power supply terminal V2 is pulled up to the signal of the first power supply terminal V1, that is, the first electrode signal (positive signal) of the battery pack 30, the first The second detection unit 420 can output a second level signal to determine that the first transistor M1 is in an off state. In the case that the first transistor M1 and the second transistor M2 are broken down, the signal of the second power supply terminal V2 is the second electrode signal (a negative signal, such as a ground signal) of the battery pack 30, and the second detection unit 420 can output the first A level signal to determine that the first transistor M1 is in an on state.

The input end of the third detection unit 430 is connected between the battery pack 30 and the switch module 10 and connected to the current signal VRs. The third detection unit 430 can determine the first transistor M1 by comparing the current signal VRs with the set current. Whether there is current flowing, to further determine the conduction state of the first transistor M1, for example, the set current can be the minimum operating current of the first transistor M1, when the current signal VRs is greater than or equal to the set current, it can be determined that the first transistor M1 M1 is in an on state, and the third detection unit 430 can output a first level signal. When the current signal VRs is smaller than the set current, it can be determined that the first transistor M1 is in an off state, and the third detection unit 430 can output a second level signal.

When the gate signal Vg of the first transistor M1 is an off-level signal and the first transistor M1 is broken down, the first detection unit 410 , the second detection unit 420 and the third detection unit 430 all output the first level signal, the AND gate circuit 440 can output a first level signal according to the signals of its own first input terminal, second input terminal and third input terminal, so as to control the first switch K1 to be turned on by the first level signal, and then The fuse device 210 is controlled to be blown to protect the battery pack 30 .

It should be noted that, the above-mentioned embodiment only takes the gate of the first transistor M1 as the control terminal of the switch module 10, and the first detection module 40 controls the fuse device 210 according to the state of the first transistor M1 as an example for description. In other embodiments, the gate of the second transistor M2 can also be used as the control terminal of the switch module 10, and the first detection module 40 can also control the fuse device 210 according to the state of the second transistor M2, which is not in this embodiment. be limited.

FIG. 4 is a schematic structural diagram of a first detection module, a delay module, and a second detection module provided by an embodiment of the present invention. FIG. 4 shows a fuse module 20, a first detection module 40, a control module 50, and a delay module. 60 and the connection between the second detection module 70. 2 and 4, further, the first detection unit 410 includes a first diode D1, a first resistor R1 and a second switch K2, the anode of the first diode D1 is connected to the control terminal of the switch module 10, the first The cathode of a diode D1 is connected to the control terminal of the second switch K2, the first terminal of the second switch K2 is connected to the power terminal VCC through the first resistor R1, and the second terminal of the second switch K2 is grounded. Among them, the first diode D1 is used to prevent signal backflow, the first resistor R1 is used to divide the voltage, and the second switch K2 can be a transistor, such as a triode or a field effect transistor. In this embodiment, the second switch K2 can be set as triode, then the base of the triode can be used as the control terminal of the second switch K2, one of the collector and the emitter of the triode can be used as the first end of the second switch K2, and the other is used as the second terminal of the second switch K2 end.

The second detection unit 420 includes a second diode D2, a second resistor R2 and a third switch K3, the anode of the second diode D2 is connected to the second power supply terminal V2, and the cathode of the second diode D2 is connected to the third switch The control terminal of K3, the first terminal of the third switch K3 is connected to the power terminal VCC through the second resistor R2, and the second terminal of the third switch K3 is grounded. Among them, the second diode D2 is used to prevent signal backflow, the second resistor R2 is used to divide the voltage, and the third switch K3 can be a transistor, such as a triode or a field effect transistor, etc. In this embodiment, the third switch K3 can be set to be triode, then the base of the triode can be used as the control terminal of the third switch K3, one of the collector and the emitter of the triode can be used as the first end of the third switch K3, and the other can be used as the second terminal of the third switch K3 end.

The third detection unit 430 includes a first comparator F1, a third resistor R3, a fourth resistor R4 and a fifth resistor R5. The first end of the third resistor R3 is connected to the reference voltage terminal to access the reference voltage Vref, and the third resistor The second end of R3 is connected to the first end of the fourth resistor R4, the second end of the fourth resistor R4 is grounded, the first comparison signal input end of the first comparator F1 is connected to the second end of the third resistor R3, and the battery pack 30 A sixth resistor R6 is connected in series with the switch module 10 , the second comparison signal input terminal of the first comparator F1 is connected to the sixth resistor R6 , and the output terminal of the first comparator F1 is connected to the power terminal VCC through the fifth resistor R5 . The third resistor R3, the fourth resistor R4 and the fifth resistor R5 are all used for voltage division.

The AND gate circuit 440 includes a third diode D3, a fourth diode D4, a fifth diode D5 and a seventh resistor R7, the first end of the seventh resistor R7 is connected to the power supply terminal VCC, and the third diode D3 The cathode of the fourth diode D4 is connected to the first end of the second switch K2, the cathode of the fourth diode D4 is connected to the first end of the third switch K3, the cathode of the fifth diode D5 is connected to the output end of the first comparator F1, and the third The anode of the diode D3 , the anode of the fourth diode D4 and the anode of the fifth diode D5 are connected to the second end of the seventh resistor R7 , and the second end of the seventh resistor R7 is connected to the control end of the fuse module 20 . Among them, the seventh resistor R7 is used for voltage division.

With reference to FIG. 2 and FIG. 4 , further, the battery protection circuit further includes a delay module 60 and a second detection module 70 . The delay module 60 is connected between the first detection module 40 and the control terminal of the fusing module 20 , and is used to delay outputting the output signal of the first detection module 40 to the control terminal of the fusing module 20 . The second detection module 70 is connected to the delay module 60 . The second detection module 70 is used to detect the temperature of the switch module 10 and control the delay time of the delay module 60 to shorten when the temperature of the switch module 10 is greater than or equal to the set temperature.

Specifically, the delay module 60 can be connected between the first detection module 40 and the control terminal of the first switch K1, and the delay module 60 can delay the output signal of the first detection module 40 for a set period of time and output it to the first The control terminal of the switch K1 controls the fuse device 210 through the first switch K1, so as to realize the delay function and avoid false triggering. The second detection module 70 can shorten the delay time of the delay module 60 when the temperature of the first transistor M1 and/or the second transistor M2 in the switch module 10 is greater than or equal to the set temperature, so that the delay module The delay time of 60 is less than the set time length, so that when the temperature of the first transistor M1 and/or the second transistor M2 is too high, the control speed of the first detection module 40 for the first switch K1 can be increased, and the fuse device 210 can be accelerated. Response to achieve the effect of temperature abnormal protection.

2 and 4, further, the delay module 60 includes an eighth resistor R8 and a first capacitor C1, the eighth resistor R8 is connected between the first detection module 40 and the control terminal of the fuse module 20, and the first capacitor C1 The first pole of the first capacitor C1 is connected between the eighth resistor R8 and the control terminal of the fuse module 20, and the second pole of the first capacitor C1 is grounded.

The second detection module 70 includes a ninth resistor R9, a tenth resistor R10, an eleventh resistor R11, a thermistor NTC, an optocoupler device 710, a second comparator F2, and a fourth switch K4. The first The terminal is connected to the power supply terminal VCC, the second terminal of the ninth resistor R9 is connected to the first terminal of the thermistor NTC, the second terminal of the thermistor NTC is grounded, and the first comparison signal input terminal of the second comparator F2 is connected to the reference voltage Vref, the second comparison signal input terminal of the second comparator F2 is connected to the second terminal of the ninth resistor R9, the tenth resistor R10 is connected between the output terminal of the second comparator F2 and the second comparison signal input terminal, and the tenth resistor R10 is connected between the output terminal of the second comparator F2 and the second comparison signal input terminal. A resistor R11 is connected between the output terminal of the second comparator F2 and the power terminal VCC, the output terminal of the second comparator F2 is connected to the control terminal of the fourth switch K4, and the first input terminal of the optocoupler device 710 is connected to the power terminal VCC, the first output end of the optocoupler device 710 is connected to the first end of the fourth switch K4, the second end of the fourth switch K4 is grounded, the second input end of the optocoupler device 710 is connected to the first end of the eighth resistor R8, The second output terminal of the optocoupler device 710 is connected to the second terminal of the eighth resistor R8.

Among them, the thermistor NTC is used to detect the temperature of the switch module. The fourth switch K4 can be a transistor, such as a triode or a field effect transistor, etc. In this embodiment, the fourth switch K4 can be set to be a triode, then the base of the triode can be used as the control end of the fourth switch K4, the collector and the emitter of the triode. One of the poles can be used as the first terminal of the fourth switch K4, and the other is used as the second terminal of the fourth switch K4. The ninth resistor R9 and the eleventh resistor R11 are used for voltage division, and the tenth resistor R10 is used as a feedback resistor.

2 and 4 , on the basis of the foregoing embodiments, optionally, the first detection unit 410 further includes a first Zener diode E1 , a twelfth resistor R12 , a thirteenth resistor R13 and a second capacitor C2 . The first Zener diode E1 and the twelfth resistor R12 are sequentially connected in series between the first diode D1 and the control terminal of the second switch K2, and the thirteenth resistor R13 is connected to the control terminal and the second terminal of the second switch K2. In between, the second capacitor C2 is connected in parallel with the thirteenth resistor R13. A fourteenth resistor R14 is also connected between the first end of the second switch K2 and the third diode D3. The first Zener diode E1 is used for voltage regulation to improve the stability of the signal, so that the signal on the first Zener diode E1 needs to reach a certain value to be effective, thereby reducing the probability of false triggering. The twelfth resistor R12 and the fourteenth resistor R14 are used for current limiting, and the thirteenth resistor R13 and the second capacitor C2 are used for filtering.

The second detection unit 420 further includes a second Zener diode E2, a fifteenth resistor R15, a sixteenth resistor R16 and a third capacitor C3. The second Zener diode E2 and the fifteenth resistor R15 are sequentially connected in series between the second diode D2 and the control terminal of the third switch K3, and the sixteenth resistor R16 is connected to the control terminal and the second terminal of the third switch K3 In between, the third capacitor C3 is connected in parallel with the sixteenth resistor R16. A seventeenth resistor R17 is also connected between the first end of the third switch K3 and the fourth diode D4. Among them, the second Zener diode E2 is used for voltage regulation to improve the stability of the signal, so that the signal on the second Zener diode E2 needs to reach a certain value to be effective, thereby reducing the probability of false triggering. The fifteenth resistor R15 and the seventeenth resistor R17 are used for current limiting, and the sixteenth resistor R16 and the third capacitor C3 are used for filtering.

The third detection unit 430 further includes an eighteenth resistor R18, a nineteenth resistor R19, a fourth capacitor C4 and a fifth capacitor C5. The eighteenth resistor R18 is connected between the third resistor R3 and the first comparison signal input terminal of the first comparator F1, and the nineteenth resistor R19 is connected between the sixth resistor R6 and the second comparison signal input of the first comparator F1 between the ends. The first pole of the fourth capacitor C4 is connected to the second comparison signal input terminal of the first comparator F1, and the second pole of the fourth capacitor C4 is grounded. The first pole of the fifth capacitor C5 is connected to the output end of the first comparator F1, and the second pole of the fifth capacitor C5 is grounded. A twentieth resistor R20 is also connected between the output end of the first comparator F1 and the fifth diode D5. The eighteenth resistor R18, the nineteenth resistor R19 and the twentieth resistor R20 are used for current limiting, and the fourth capacitor C4 and the fifth capacitor C5 are used for filtering.

The AND gate circuit 440 further includes a sixth capacitor C6, the first end of the sixth capacitor C6 is connected to the second end of the seventh resistor R7, and the second end of the sixth capacitor C6 is grounded. The sixth capacitor C6 is used for filtering.

The second detection module 70 further includes a twenty-first resistor R21, a twenty-second resistor R22 and a seventh capacitor C7. The twenty-first resistor R21 is connected between the output terminal of the second comparator F2 and the control terminal of the fourth switch K4. The twenty-second resistor R22 is connected between the power terminal VCC and the first input terminal of the optocoupler device 710 . The first pole of the seventh capacitor C7 is connected to the second comparison signal input end of the second comparator F2, and the second pole of the seventh capacitor C7 is grounded. The twenty-first resistor R21 is used for current limiting, the twenty-second resistor R22 is used for voltage division, and the seventh capacitor C7 is used for filtering.

Further, the battery protection circuit further includes a twenty-third resistor R23, a twenty-fourth resistor R24, a sixth diode D6 and a seventh diode D7. The twenty-third resistor R23 and the seventh diode D7 are connected in series between the eighth resistor R8 and the control terminal of the fuse module 20, the anode of the seventh diode D7 is connected to the twenty-third resistor R23, and the seventh diode The cathode of D7 is connected to the control terminal of the fuse module 20 . The first end of the twenty-fourth resistor R24 is connected to the control end of the fuse module 20, and the second end of the twenty-fourth resistor R24 is grounded. The control module 50 is connected to the control terminal of the fusing module 20 through the sixth diode D6 , the anode of the sixth diode D6 is connected to the control module 50 , and the cathode of the sixth diode D6 is connected to the control terminal of the fusing module 20 . Among them, the twenty-third resistor R23 and the twenty-fourth resistor R24 are used for current limiting, and the sixth diode D6 and the seventh diode D7 are used to prevent signal backflow.

2 and 4, the first electrode of the battery pack 30 is the positive pole, the second electrode of the battery pack 30 is the negative pole, the first power supply terminal V1 is the power supply positive pole, the second power supply terminal V2 is the power supply negative pole, and the first transistor The gate of M1 is used as the control terminal of the switch module 10, the first level signal is a high level signal, and the second level signal is a low level signal, which controls the first transistor M1, the second transistor M2, the first switch K1 to Taking the signal that the fourth switch K4 is turned on is a high-level signal as an example, the overall working principle of the battery protection circuit is explained:

Exemplarily, when the battery pack 30 and the battery protection circuit are in the working state, a load is connected between the first power supply terminal V1 and the second power supply terminal V2, and the gate voltage signals of the first transistor M1 and the second transistor M2 are both. With a low level signal, the normal state of the first transistor M1 and the second transistor M2 at this time is an off state. The first detection module 40 performs fault detection on the first transistor M1. The input terminal of the first detection unit 410 is connected to the gate voltage signal Vg of the first transistor M1, and the gate voltage signal Vg is a low level signal. The level signal can pass through the first diode D1, the first Zener diode E1, the twelfth resistor R12 in turn, and then enter the control terminal of the second switch K2 after being filtered by the second capacitor C2 and the thirteenth resistor R13, The second switch K2 is turned off, and the output terminal of the first detection unit 410 (ie, the first terminal of the second switch K2 ) outputs a high-level signal, so that the first input terminal of the AND gate circuit 440 (ie, the third diode The cathode of D3) input high level signal. When the battery pack 30 and the battery protection circuit are impacted by an external signal, causing the first transistor M1 and the second transistor M2 to break down, the first transistor M1 and the second transistor M2 are in a conducting state, and the battery pack 30 The negative electrode and the second power supply terminal V2 are in a conducting state, and the input terminal of the second detection unit 420 is connected to the signal of the second power supply terminal V2, which is a low-level signal, and the low-level signal can pass through the second diode in turn. The tube D2, the second Zener diode E2 and the fifteenth resistor R15 are filtered by the third capacitor C3 and the sixteenth resistor R16 and then enter the control terminal of the third switch K3, so that the third switch K3 is turned off, and the second The output terminal of the detection unit 420 (ie, the first terminal of the third switch K3 ) outputs a high-level signal, so that the second input terminal of the AND gate circuit 440 (ie, the cathode of the fourth diode D4 ) inputs a high-level signal. When the first transistor M1 and the second transistor M2 are in the conducting state, there is current between the battery pack 30, the battery protection circuit and the load, and the input terminal of the third detection unit 430 is connected to the current signal VRs, and the reference voltage is set by setting the reference voltage. The values of Vref, the third resistor R3 and the fourth resistor R4 can be used to detect whether there is current between the battery pack 30 and the switch module 10 through the third detection unit 430. For example, when the current signal VRs is greater than zero, so that at this time The voltage of the second comparison signal input terminal of the first comparator F1 is greater than the voltage of the first comparison signal input terminal, and the first comparator F1 outputs a high-level signal, so that the third input terminal of the AND gate circuit 440 (ie, the fifth diode The cathode of tube D5) inputs a high level signal. The advantage of this setting is that it can ensure that the detection results of the first detection unit 410 and the second detection unit 420 are measured when there is current between the battery pack 30 and the switch module 10, which helps to avoid the existence of detection results. error. In this way, in the case of breakdown of the first transistor M1 and the second transistor M2, the first input terminal, the second input terminal and the third input terminal of the AND gate circuit 440 are all input with high-level signals, and the AND gate circuit 440 outputs a high-level signal, which is filtered and delayed by the eighth resistor R8 and the first capacitor C1 and transmitted to the control terminal of the first switch K1, so that the first switch K1 is turned on, thereby triggering the fuse device 210 It is blown to protect the battery pack 30 .

At the same time, the thermistor NTC in the second detection module 70 can detect the temperature of the first transistor M1 and the second transistor M2, and by setting the size of the ninth resistor R9, the first transistor M1 and the second transistor M2 can be When the temperature is greater than or equal to the set temperature, the voltage of the second comparison signal input terminal of the second comparator F2 is greater than the voltage of the first comparison signal input terminal, and the second comparator F2 outputs a high-level signal, so that the fourth switch K4 conducts turn on, so that the first input terminal and the first output terminal of the optocoupler device 710 are connected, and the second input terminal and the second output terminal are connected, and the eighth resistor R8 is short-circuited, so as to shorten the delay module 60 The delay time is longer, so that the fuse device 210 has a fast fuse response.

When the gate voltage signals of the first transistor M1 and the second transistor M2 are both low-level signals, and the first transistor M1 and the second transistor M2 are in the normal state, that is, the off state, the first detection unit 410 The output terminal still outputs a high-level signal, so that the first input terminal of the AND gate circuit 440 still inputs a high-level signal. In the case that the first transistor M1 and the second transistor M2 are in the off state, the second electrode of the battery pack 30 and the second power supply terminal V2 are in the off state, since the connection between the first power supply terminal V1 and the second power supply terminal V2 is When a load is connected, the signal of the second power supply terminal V2 will be pulled up to the signal of the first power supply terminal V1, that is, the positive signal of the battery pack 30. This signal is a high-level signal, and the high-level signal can pass through the The second diode D2, the second Zener diode E2 and the fifteenth resistor R15 are filtered by the third capacitor C3 and the sixteenth resistor R16 and then enter the control terminal of the third switch K3, so that the third switch K3 is turned on , the output terminal of the second detection unit 420 outputs a low-level signal, so that the second input terminal of the AND gate circuit 440 inputs a low-level signal. When the first transistor M1 and the second transistor M2 are in the off state, there is no current between the battery pack 30, the battery protection circuit and the load, by setting the reference voltage Vref, the values of the third resistor R3 and the fourth resistor R4 , when the current signal VRs is zero, the voltage of the second comparison signal input terminal of the first comparator F1 is lower than the voltage of the first comparison signal input terminal, and the first comparator F1 outputs a low-level signal, so that the A low-level signal is input to the third input terminal of the AND gate circuit 440 . In this way, when the first transistor M1 and the second transistor M2 are in a normal state, both the first input terminal and the third input terminal of the AND gate circuit 440 are input with a high level signal, and the second input terminal is input with a low level signal signal, the gate circuit 440 outputs a low level signal, the first switch K1 is turned off, and the fuse device 210 remains in its original state. At the same time, the control module 50 can also control the first switch K1 to be turned on or off, so as to control the fuse device 210 .

In the technical solution of the embodiment of the present invention, the state of the transistor in the switch module 10 is detected by the first detection module 40, and the transistor in the switch module 10 is broken down when the battery pack 30 and the battery protection circuit are impacted by external signals. In the case of damage, the first detection module 40 can control the first switch K1 to be turned on to trigger the fuse device 210 to fuse to protect the battery pack 30. Since the delay module 60 has a delay function, it helps to prevent the fuse device from being blown. In addition, when the transistor in the switch module 10 breaks down and the temperature is too high, the delay time of the delay module 60 can also be shortened by the second detection module 70, thereby triggering the fuse device 210 to quickly fuse , which helps to improve the safety and reliability of the battery pack 30 and the battery protection circuit.

Embodiments of the present invention further provide a battery management system, including a battery pack and a battery protection circuit in any embodiment of the present invention. Therefore, the battery management system has the corresponding functional structure and beneficial effects of the battery protection circuit, which will not be repeated here.

The embodiment of the present invention also provides a method for controlling a battery protection circuit, which is used to control the battery protection circuit in any embodiment of the present invention. FIG. 5 is a schematic flowchart of a control method of a battery protection circuit further provided by an embodiment of the present invention. Referring to FIG. 5, the control method of the battery protection circuit specifically includes the following steps:

S110. Acquire signals from the second power supply terminal and the control terminal of the switch module through the first detection module.

S120: Determine the conduction state of the switch module according to the signal of the second power supply terminal by the first detection module.

S130: Control the fuse module to disconnect by the first detection module when the signal at the control end of the switch module is an off-level signal and the switch module is in an on state.

The technical solution of the embodiment of the present invention is to obtain the signals of the second power supply terminal and the control terminal of the switch module through the first detection module, determine the conduction state of the switch module according to the signal of the second power supply terminal, and take the signal at the control terminal of the switch module as the off state. When the level signal is off and the switch module is in the on state, it is determined that the switch module is broken down and damaged, so that the first detection module controls the fuse module to disconnect, so as to trigger the fuse module when the battery pack and battery protection circuit are impacted by external signals. Normal start, to achieve protection in abnormal state, help to enhance the safety and reliability of the battery pack and battery protection circuit.

On the basis of the above embodiment, optionally, the first detection module includes a first detection unit, a second detection unit, a third detection unit and an AND gate circuit; the input end of the first detection unit is connected to the control end of the switch module, The output end of the first detection unit is connected to the first input end of the AND gate circuit; the input end of the second detection unit is connected to the second power supply end, the output end of the second detection unit is connected to the second input end of the AND gate circuit, and the battery pack The first electrode is connected to the first power supply terminal, the switch module is connected between the second electrode of the battery pack and the second power supply terminal, and a load is connected between the first power supply terminal and the second power supply terminal; the input terminal of the third detection unit is connected to Between the battery pack and the switch module, the output end of the third detection unit is connected to the third input end of the AND gate circuit; the output end of the AND gate circuit is connected to the control end of the fuse module. Correspondingly, step S120 and step S130 specifically include:

The first detection unit outputs a first level signal when the signal at the control end of the switch module is an off-level signal, and outputs a second level signal when the signal at the control end of the switch module is an on-level signal;

The second detection unit outputs the first level signal when the signal at the second power supply terminal is the second electrode signal of the battery pack, and outputs the second level signal when the signal at the second power supply terminal is the first electrode signal of the battery pack;

The third detection unit outputs a first level signal when the current between the battery pack and the switch module is greater than or equal to the set current, and outputs a second level signal when the current between the battery pack and the switch module is less than the set current ;

The AND gate circuit outputs the first level signal to the control terminal of the fuse module to control the fuse module to disconnect when the signals at its first input terminal, the second input terminal and the third input terminal are all first level signals.

Optionally, the battery protection circuit further includes a delay module and a second detection module; the delay module is connected between the first detection module and the control terminal of the fuse module, and the second detection module is connected to the delay module;

The control method of the battery protection circuit also includes:

The output signal of the first detection module is delayed and output to the control terminal of the fuse module through the delay module;

The temperature of the switch module is detected by the second detection module, and when the temperature of the switch module is greater than or equal to the set temperature, the delay time of the delay module is controlled to shorten.

Embodiments of the present invention also provide a battery management system, where the battery management system applies the control method of the battery protection circuit in any of the foregoing embodiments. In the battery management system provided by the embodiment of the present invention, the signals of the second power supply terminal and the control terminal of the switch module are obtained through the first detection module, and the conduction state of the switch module is determined according to the signal of the second power supply terminal, and the signal at the control terminal of the switch module is used to determine the conduction state of the switch module. In order to turn off the level signal and the switch module is in the on state, it is determined that the switch module is damaged by breakdown, so that the first detection module controls the fuse module to disconnect, so as to realize the triggering when the battery pack and the battery protection circuit are impacted by external signals, etc. The fuse module starts normally, achieves the protection function in abnormal state, and helps to enhance the safety and reliability of the battery pack and the battery protection circuit.

It should be understood that steps may be reordered, added or deleted using the various forms of flow shown above. For example, the steps described in the present invention can be performed in parallel, sequentially or in different orders, and as long as the desired results of the technical solutions of the present invention can be achieved, no limitation is imposed herein.

The above-mentioned specific embodiments do not constitute a limitation on the protection scope of the present invention. It should be understood by those skilled in the art that various modifications, combinations, sub-combinations and substitutions may occur depending on design requirements and other factors. Any modifications, equivalent replacements and improvements made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims (10)

1. A battery protection circuit, characterized in that, comprising: A switch module and a fuse module, the switch module, the fuse module and the battery pack are connected in series between the first power supply terminal and the second power supply terminal; the switch module is arranged close to the second power supply terminal, and the switch module is used for It is turned on or off in response to the signal of its own control end to control the charging and discharging of the battery pack; the fuse module is used to disconnect in response to the signal of its own control end; The first detection module is connected to the second power supply terminal, the control terminal of the switch module and the control terminal of the fuse module, and is used for acquiring the signals of the second power supply terminal and the control terminal of the switch module, according to the The signal of the second power supply terminal determines the conduction state of the switch module, and controls the fuse module to disconnect when the signal of the control terminal of the switch module is an off-level signal and the switch module is in the conduction state. 2. The battery protection circuit according to claim 1, wherein the fuse module comprises a first switch and a fuse device; The control end of the first switch serves as the control end of the fuse module, the first end of the first switch is connected to the control end of the fuse device, the second end of the first switch is grounded, and the fuse device connected in series with the switch module and the battery pack; The first switch is configured to be turned on or off according to a signal of its own control terminal, so as to control the fuse device to be turned off when turned on; The fuse device includes a three-terminal fuse. 3 . The battery protection circuit according to claim 1 , wherein the battery protection circuit further comprises a control module, and the control module is connected to the battery pack, the control terminal of the switch module and the fuse module. 4 . a control terminal, used to control the switch module and the fuse module; The switch module includes a first transistor and a second transistor, the first transistor and the second transistor are connected in series between the first power supply terminal and the second power supply terminal, the first transistor and/or The gate of the second transistor serves as the control terminal of the switch module. 4. The battery protection circuit according to claim 1, wherein the first detection module comprises a first detection unit, a second detection unit, a third detection unit and an AND gate circuit; The input end of the first detection unit is connected to the control end of the switch module, the output end of the first detection unit is connected to the first input end of the AND gate circuit, and the first detection unit is used for The first level signal is output when the signal of the control terminal of the switch module is the off-level signal, and the second level signal is output when the signal of the control terminal of the switch module is the on-level signal; The input end of the second detection unit is connected to the second power supply end, the output end of the second detection unit is connected to the second input end of the AND gate circuit, and the first electrode of the battery pack is connected to the first electrode. A power supply terminal, the switch module is connected between the second electrode of the battery pack and the second power supply terminal, a load is connected between the first power supply terminal and the second power supply terminal, and the first power supply terminal is connected to the second power supply terminal. The second detection unit is configured to output the first level signal when the signal at the second power supply terminal is the second electrode signal of the battery pack, and the signal at the second power supply terminal is the first electrode of the battery pack outputting the second level signal when the signal is present; The input end of the third detection unit is connected between the battery pack and the switch module, the output end of the third detection unit is connected to the third input end of the AND gate circuit, and the third detection unit for outputting the first level signal when the current between the battery pack and the switch module is greater than or equal to a set current, and the current between the battery pack and the switch module is less than the set current outputting the second level signal when the current is constant; The output end of the AND gate circuit is connected to the control end of the fuse module, and the AND gate circuit is used for the signals at its first input end, the second input end and the third input end to be the first level When the signal is received, the first level signal is output to the control terminal of the fuse module to control the fuse module to disconnect. 5 . The battery protection circuit according to claim 4 , wherein the first detection unit comprises a first diode, a first resistor and a second switch, and an anode of the first diode is connected to the The control terminal of the switch module, the cathode of the first diode is connected to the control terminal of the second switch, the first terminal of the second switch is connected to the power terminal through the first resistor, and the second switch is connected to the power terminal through the first resistor. The second terminal is grounded; The second detection unit includes a second diode, a second resistor and a third switch, the anode of the second diode is connected to the second power supply terminal, and the cathode of the second diode is connected to the the control terminal of the third switch, the first terminal of the third switch is connected to the power terminal through the second resistor, and the second terminal of the third switch is grounded; The third detection unit includes a first comparator, a third resistor, a fourth resistor and a fifth resistor, a first end of the third resistor is connected to a reference voltage end, and a second end of the third resistor is connected to the The first end of the fourth resistor, the second end of the fourth resistor are grounded, the first comparison signal input end of the first comparator is connected to the second end of the third resistor, the battery pack and the A sixth resistor is connected in series between the switch modules, the second comparison signal input terminal of the first comparator is connected to the sixth resistor, and the output terminal of the first comparator is connected to the power supply terminal through the fifth resistor; The AND gate circuit includes a third diode, a fourth diode, a fifth diode and a seventh resistor, the first end of the seventh resistor is connected to the power supply end, and the cathode of the third diode connected to the first end of the second switch, the cathode of the fourth diode is connected to the first end of the third switch, and the cathode of the fifth diode is connected to the output end of the first comparator , the anode of the third diode, the anode of the fourth diode and the anode of the fifth diode are connected to the second end of the seventh resistor, and the second end of the seventh resistor Connect to the control terminal of the fuse module. 6. The battery protection circuit according to any one of claims 1-5, further comprising a delay module and a second detection module; The delay module is connected between the first detection module and the control terminal of the fuse module, and is used for delaying the output of the output signal of the first detection module to the control terminal of the fuse module; The second detection module is connected to the delay module, and the second detection module is used to detect the temperature of the switch module, and control the delay module when the temperature of the switch module is greater than or equal to a set temperature The delay time is shortened. 7 . The battery protection circuit according to claim 6 , wherein the delay module comprises an eighth resistor and a first capacitor, and the eighth resistor is connected to the first detection module and the fuse module. 8 . between the control terminals, the first pole of the first capacitor is connected between the eighth resistor and the control terminal of the fuse module, and the second pole of the first capacitor is grounded; The second detection module includes a ninth resistor, a tenth resistor, an eleventh resistor, a thermistor, an optocoupler device, a second comparator and a fourth switch, and the first end of the ninth resistor is connected to the power supply end, The second end of the ninth resistor is connected to the first end of the thermistor, the second end of the thermistor is grounded, and the first comparison signal input end of the second comparator is connected to the reference voltage, so The second comparison signal input end of the second comparator is connected to the second end of the ninth resistor, and the tenth resistor is connected between the output end of the second comparator and the second comparison signal input end, so The eleventh resistor is connected between the output end of the second comparator and the power supply end, the output end of the second comparator is connected to the control end of the fourth switch, and the first input of the optocoupler device The terminal is connected to the power terminal, the first output terminal of the optocoupler device is connected to the first terminal of the fourth switch, the second terminal of the fourth switch is grounded, and the second input terminal of the optocoupler device is connected to the The first end of the eighth resistor, and the second output end of the optocoupler device is connected to the second end of the eighth resistor. 8. A control method for a battery protection circuit, wherein the battery protection circuit comprises: a switch module, a fuse module and a first detection module; the switch module, the fuse module and the battery pack are connected to a first power supply between the terminal and the second power terminal; the switch module is disposed close to the second power terminal, and the switch module is used to turn on or off in response to a signal from its own control terminal to control the charging and discharging of the battery pack; so the fuse module is used for disconnecting in response to a signal from its own control terminal; the first detection module is connected to the second power terminal, the control terminal of the switch module and the control terminal of the fuse module; The control method of the battery protection circuit includes: Obtain the signals of the second power supply terminal and the control terminal of the switch module through the first detection module; Determine the conduction state of the switch module by the first detection module according to the signal of the second power supply terminal; The fuse module is controlled to be disconnected by the first detection module when the signal at the control end of the switch module is an off-level signal and the switch module is in an on state. 9 . The control method of a battery protection circuit according to claim 8 , wherein the battery protection circuit further comprises a delay module and a second detection module; the delay module is connected to the first detection module and the second detection module. 10 . Between the control terminals of the fuse module, the second detection module is connected to the delay module; The control method of the battery protection circuit also includes: The output signal of the first detection module is delayed and output to the control terminal of the fuse module through the delay module; The temperature of the switch module is detected by the second detection module, and when the temperature of the switch module is greater than or equal to a set temperature, the delay time of the delay module is controlled to shorten. 10. A battery management system, characterized by comprising a battery pack and the battery protection circuit according to any one of claims 1-7, or a battery protection circuit applying the battery protection circuit according to any one of claims 8-9. Control Method.

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