CN115498595A

CN115498595A - Short-circuit protection circuit, power battery pack and vehicle

Info

Publication number: CN115498595A
Application number: CN202211106139.5A
Authority: CN
Inventors: 刘光生; 王杭挺; 刘安龙
Original assignee: Guangzhou Xiaopeng Motors Technology Co Ltd
Current assignee: Guangzhou Xiaopeng Motors Technology Co Ltd
Priority date: 2022-09-09
Filing date: 2022-09-09
Publication date: 2022-12-20

Abstract

The application discloses short-circuit protection circuit, power battery package and vehicle. The short-circuit protection circuit includes: the first driving module comprises a fusing circuit and a detection circuit, and the fusing circuit is connected between the first connecting end and the second connecting end in series; the detection circuit is connected in parallel at two ends of the fusing circuit; the circuit breaking module comprises a responder and a circuit breaker, and the circuit breaker and the fusing circuit are connected in series between a first connecting end and a second connecting end; the responder is connected to the detection circuit and is connected with the circuit breaker; the open circuit detection module is connected to the detection circuit; the control module is connected to the open circuit detection module and configured to: and acquiring port voltages of the first detection port and the second detection port, and judging whether the detection circuit is in an open circuit state or not based on the port voltages. The short-circuit protection circuit has a circuit breaking detection function, and the situation that the circuit breaker cannot be triggered to cut off an external load circuit after the fusing circuit is fused under the situation that a circuit between the fusing circuit and a responder is broken is avoided.

Description

Short-circuit protection circuit, power battery pack and vehicle

Technical Field

The application relates to the technical field of power electronics, in particular to a short-circuit protection circuit, a power battery pack and a vehicle.

Background

With the continuous development of lithium battery technology, the charging power corresponding to the power battery in the new energy automobile is gradually increased, but the risk of thermal runaway of the power battery is increased.

In order to ensure the safe use of the power battery, the short-circuit protection scheme of the power battery system continuously tends to replace the conventional thermal fuse in series connection in the main circuit of the power battery with a circuit breaker (e.g., a pyrotechnic circuit breaker). The circuit breaker is a device which drives the point explosion through an external driver so as to cut off the main circuit of the power battery. Compare with traditional hot melt formula fuse, the electric arc can not appear after the circuit breaker cuts off the circuit, can avoid electric arc to cause the condition of harm to external equipment to take place.

However, the scheme of controlling the circuit breaker by the external driver puts extremely high requirements on the short-circuit current judgment capability, the software diagnosis decision capability and the system reliability of the external controller. Once the external driver fails, when the power battery fails, the external driver cannot timely control the circuit breaker to cut off the branch between the power battery and the external device, so that the external device is damaged difficultly repaired.

Disclosure of Invention

The embodiment of the application provides a short-circuit protection circuit, a power battery pack and a vehicle.

Some embodiments of the present application provide a short-circuit protection circuit, wherein the short-circuit protection circuit has a first connection terminal and a second connection terminal for connecting an external load circuit, and the short-circuit protection circuit includes a first driving module, a circuit breaking detection module, and a control module. The first driving module comprises a fusing circuit and a detection circuit, and the fusing circuit is connected between the first connecting end and the second connecting end in series; the detection circuit is connected in parallel at two ends of the fusing circuit and used for acquiring detection voltages at two ends of the fusing circuit; the circuit breaking module comprises a responder and a circuit breaker, and the circuit breaker and the fusing circuit are connected in series between a first connecting end and a second connecting end; the responder is connected to the detection circuit and is connected with the circuit breaker, and the responder is used for triggering the circuit breaker to cut off a circuit between the first connecting end and the second connecting end under the condition that the detection voltage is greater than the specified voltage; the open circuit detection module is provided with a first detection port and a second detection port, and the first detection port and the second detection port are connected to two ends of the detection circuit in parallel; the control module is connected to the open circuit detection module and configured to: and acquiring port voltages of the first detection port and the second detection port, and judging whether the detection circuit is in an open circuit state or not based on the port voltages.

Some embodiments of the present application further provide a power battery pack, including: the short-circuit protection circuit comprises a battery pack and the short-circuit protection circuit, wherein a first connecting end and a second connecting end of the short-circuit protection circuit are respectively connected to the anode and the cathode of the battery pack.

Some embodiments of the present application further provide a vehicle, comprising: the power battery pack comprises a shell and the power battery pack, wherein the power battery pack is arranged in the shell.

The application discloses short-circuit protection circuit, power battery package and vehicle. The short-circuit protection circuit is connected with an external load circuit through a first connecting end and a second connecting end, a fusing circuit and a circuit breaker are connected in series between the first connecting end and the second connecting end, and the circuit breaker is connected with the responder. The responder is connected to the detection circuits connected in parallel at two ends of the fusing circuit, when the fusing circuit is in a fusing state, the detection voltage at two ends of the fusing circuit is greater than a specified voltage, and the responder triggers the circuit breaker to cut off a circuit between the first connecting end and the second connecting end. Therefore, under the condition that the external load circuit is short-circuited, the fusing circuit is fused to trigger the breaker to cut off the external load circuit, namely, the circuit breaking module can realize the quick cut-off of the external load circuit without being connected with an external driver, and the hardware cost of the circuit is saved.

In addition, the short-circuit protection circuit in the application further comprises a circuit breaking detection module and a control module, wherein the circuit breaking detection module is connected to two ends of the detection circuit in parallel. The control module is connected to the disconnection detection module and judges whether the detection circuit is in a disconnection state or not based on the port voltage acquired by the disconnection detection module, namely, whether a line between the fuse circuit and the responder is disconnected or not is judged. Therefore, the short-circuit protection circuit in the application also has a function of detecting the open circuit, the condition that the circuit breaker cannot be triggered to cut off an external load circuit after the fusing circuit is fused under the condition that the circuit between the fusing circuit and the responder is broken is avoided, and the reliability of connection between the fusing circuit and the responder is ensured.

Drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed to be used in the description of the embodiments are briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present application, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without creative efforts.

Fig. 1 is a schematic diagram of an application environment of a short-circuit protection circuit provided in the present application.

Fig. 2 is a schematic structural diagram of a first possible implementation of the short-circuit protection circuit shown in fig. 1.

Fig. 3 is a schematic structural diagram of a second possible implementation of the short-circuit protection circuit shown in fig. 1.

Fig. 4 is a schematic structural diagram of a disconnection detection module provided in the present application.

Fig. 5 is a schematic diagram of a third possible implementation of the short-circuit protection circuit shown in fig. 1.

Fig. 6 is a schematic structural diagram of a fourth possible implementation of the short-circuit protection circuit shown in fig. 1.

Fig. 7 is a schematic structural diagram of a suppression unit provided in the present application.

Detailed Description

In order to make the technical solutions better understood by those skilled in the art, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. It is to be understood that the embodiments described are only a few embodiments of the present application and not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.

Referring to fig. 1, the present embodiment provides a short-circuit protection circuit 100 and a vehicle 200 equipped with the short-circuit protection circuit 100. The vehicle 200 includes a housing 210 and a power battery pack 230, wherein the power battery pack 230 is disposed in the housing 210 and is used for providing kinetic energy for the vehicle 200. Taking the vehicle 200 as a new energy vehicle as an example, the power battery pack 230 can provide driving force for the new energy vehicle, and further drive a driving system (e.g., an axle and wheels) to operate through a transmission system.

The power battery pack 230 in the embodiment of the present application includes the battery pack 2310 and the short-circuit protection circuit 100, wherein the short-circuit protection circuit 100 has a first connection terminal 10 and a second connection terminal 20 for connecting the battery pack 2310. In this embodiment, the battery pack 2310 serves as an external load circuit of the short-circuit protection circuit 100, and the short-circuit protection circuit 100 is used for short-circuit protection of the external load circuit (i.e., the battery pack 2310) to improve the safety performance of the power battery pack 230. Specifically, the first connection terminal 10 and the second connection terminal 20 of the short-circuit protection circuit 100 may be connected to the positive electrode and the negative electrode of the battery pack 2310, respectively, and the circuit between the first connection terminal 10 and the second connection terminal 20 is cut off when the battery pack 2310 is short-circuited, so as to avoid the occurrence of a situation that the external power supply device is damaged due to the out-of-control short circuit of the battery pack 2310. Specifically, the battery pack 2310 may include a plurality of cells, wherein the cells may be lithium battery cells, nickel metal hydride battery cells, and the like. It should be noted that the application environment of the short-circuit protection circuit 100 provided in the embodiment of the present application is only an exemplary embodiment, and the short-circuit protection circuit 100 may also be applied to other vehicles, electrical apparatuses, electrical control systems, and the like, which are provided with a high-voltage circuit, and the embodiment of the present application is not particularly limited.

Referring to fig. 2, the short-circuit protection circuit 100 in the embodiment of the present disclosure includes a first driving module 30, a circuit breaking module 50, a circuit breaking detection module 70, and a control module 90. The first driving module 30 is connected to the disconnection module 50, a partial structure of the first driving module 30 is connected to both ends of an external load circuit (e.g., a battery pack 2310) through a first connection terminal 10 and a second connection terminal 20, and a partial structure of the disconnection module 50 is connected to a circuit between the first connection terminal 10 and the second connection terminal 20. In the case of a short circuit occurring in an external load circuit (e.g., the battery pack 2310), the first driving module 30 may control the disconnection module 50 to disconnect the circuit between the first connection terminal 10 and the second connection terminal 20, so that the control of the disconnection module 50 can achieve a fast disconnection of the circuit without connecting an external driver, thereby saving the hardware cost of the circuit. The disconnection detecting module 70 is connected to the first driving module 30, and the control module 90 is connected to the disconnection detecting module 70, and determines whether a disconnection occurs between the first driving module 30 and the disconnection module 50 based on the voltage signal detected by the disconnection detecting module 70, thereby ensuring the reliability of the connection between the first driving module 30 and the disconnection module 50.

The various blocks in the short-circuit protection circuit 100 are described in detail below.

Referring to fig. 3, the first driving module 30 includes a fuse circuit 320 and a detecting circuit 340. The fuse circuit 320 is connected in series between the first connection terminal 10 and the second connection terminal 20, that is, the fuse circuit 320 is connected in series in a branch where the external load circuit is located, and when the external load circuit is short-circuited, the current of the branch exceeds a predetermined value, so that the fuse circuit 320 is fused. Specifically, the fuse circuit 320 may be a thermal fuse (e.g., a thermal fuse). The detection circuit 340 is connected in parallel to two terminals of the fuse circuit 320, and is used for obtaining a detection voltage across the fuse circuit 320.

The circuit interrupting module 50 includes a responder 520 and a circuit breaker 540, the responder 520 engaging the detection circuit 340. Specifically, the responder 520 is connected in parallel with the fuse circuit 320, i.e., the voltage across the responder 520 is equal to the detection voltage. When the fuse circuit 320 is in the normal state, the detected voltage is less than or equal to the specified voltage, and the responder 520 is also in the normal state. When the fuse circuit 320 is in the fuse state, the detection voltage is greater than the designated voltage, and the responder 520 is in the trigger state, so as to control the circuit breaker 540 connected with the responder 520 to operate. In some embodiments, the circuit interrupting module 50 is a pyrotechnic circuit interrupter and the responder 520 is an ignition bridge wire in the pyrotechnic circuit interrupter that, when in an activated state, ignites to activate the circuit interrupter 540 for operation.

The circuit breaker 540 is connected in series with the fuse circuit 320 between the first connection terminal 10 and the second connection terminal 20, and is connected with the responder 520. When the responder 520 triggers the circuit breaker 540 to operate, the circuit breaker 540 breaks the circuit between the first connection terminal 10 and the second connection terminal 20. Specifically, in the case where the circuit interrupting module 50 is a pyrotechnic circuit interrupter, the circuit interrupter 540 is a knife switch.

In the embodiment, a detection loop is formed between the responder 520 and the fuse circuit 320, when the fuse circuit 320 is in the blown state, and the detection voltage across the fuse circuit 320 is greater than a specified voltage, the responder 520 triggers the circuit breaker 540 to break the circuit between the first connection end 10 and the second connection end 20. That is, when the external load circuit is short-circuited, the fuse circuit 320 is blown to trigger the circuit breaker 540 to cut off the external load circuit. Therefore, the circuit breaking module 50 can realize the quick disconnection of the external load circuit without connecting an external driver, thereby saving the hardware cost of the circuit.

The open circuit detection module 70 is provided with a first detection port 710 and a second detection port 720, the first detection port 710 and the second detection port 720 are connected in parallel to two ends of the detection circuit 340, and are used for detecting port voltages of the first detection port 710 and the second detection port 720 and sending the port voltages to the control module 90 connected to the open circuit detection module 70, and the control module 90 is configured to: the port voltages of the first detection port 710 and the second detection port 720 are obtained, and whether the detection circuit 340 is in an open circuit state is determined based on the port voltages. Specifically, the specific implementation manner of the control module 90 determining whether the detection circuit 340 is in the open state based on the port voltage is described in the following embodiments. Therefore, the short-circuit protection circuit 100 in the present application further has an open circuit detection function, so as to avoid the situation that the circuit breaker 540 cannot be triggered to cut off the external load circuit after the fuse circuit 320 is fused when the line between the fuse circuit 320 and the responder 520 is open, thereby ensuring the reliability of the connection between the fuse circuit 320 and the responder 520.

Referring to fig. 4, the open circuit detection module 70 includes a power sub-module 730, a switch sub-module 740, and a voltage detection sub-module 750. The voltage detection submodule 750 is connected in parallel to two ends of the first detection port 710 and the second detection port 720, and is configured to detect port voltages of the first detection port 710 and the second detection port 720. The voltage detection sub-module 750 is further connected to the control module 90 for sending the detected port voltage to the control module 90. Specifically, the voltage detection submodule 750 may be a voltage detection device such as a hall voltage sensor or an optical fiber voltage sensor.

The switch submodule 740 is connected between the voltage detection submodule 750 and the power supply submodule 730, when the switch submodule 740 is in a conducting state, the power supply submodule 730 discharges to the detection circuit 340, and at this time, the voltage detection submodule 750 detects the port voltage. The switch submodule 740 is connected to the control module 90, that is, the switch submodule 740 is controlled to enter a conducting state by the control module 90. Accordingly, the control module 90 is further configured to: sending a trigger signal to the switch submodule 740, wherein the trigger signal is used for triggering the switch submodule 740 to enter a conducting state; when the switch submodule 740 is in the on state, the port voltages of the first detection port 710 and the second detection port 720 are obtained.

In some embodiments, the switch submodule 740 may include a plurality of resistors and transistor triacs. In the embodiment shown in fig. 4, the switch submodule 740 includes a first transistor Q1, a second transistor Q2, a first resistor R1, a second resistor R2, a third resistor R3, and a fourth resistor R4.

The first transistor Q1 is a PNP transistor, and an emitter of the first transistor Q1 is connected to the power supply sub-module 730 through a first resistor R1. The collector of the first transistor Q1 is connected to the first detection port 710. The base of the first transistor Q1 is connected to the collector of the second transistor Q2 via a third resistor R3. The second transistor Q2 is an NPN transistor, and an emitter of the second transistor Q2 is connected to the second detection port 720 and grounded. The base of the second transistor Q2 is connected to the control module 90 through a fourth resistor R4. One end of the second resistor R2 is connected to the common connection end of the first resistor R1 and the emitter of the first transistor Q1; the other end is connected with the base of the first transistor Q1 and the common connection end of the third resistor R3.

The first resistor R1 is a current-limiting resistor, and is configured to limit the current output from the power supply submodule 730 to the detection circuit 340 when the switch submodule 740 is in a conducting state. The second resistor R2 is a voltage dividing resistor, and the second resistor R2 is connected in parallel with the emitter and the base of the first transistor Q1 and is used for ensuring that the first transistor Q1 has enough starting voltage. The third resistor R3 is a collector protection resistor, and is used to avoid the short circuit of the detection circuit 340 when the first transistor Q1 and the second transistor Q2 are turned on. The fourth resistor R4 is a base current limiting resistor and is used for avoiding the situation that the base current is too large and the second crystal triode Q2 is burnt out.

The operation of the switch submodule 740 shown in fig. 4 will now be described.

The control module 90 outputs a high level signal to the second transistor Q2 through the fourth resistor R4, the second transistor Q2 enters a conducting state, and a closed loop is formed among the first resistor R1, the second resistor R2, the third resistor R3, and the second transistor Q2. In this case, the voltage across the second resistor R2 is greater than the turn-on voltage of the first transistor Q1, the first transistor Q1 enters a turn-on state, the power supply sub-module 730 discharges to the detection circuit 340 through the first resistor R1 and the first transistor Q1, and at this time, the switch sub-module 740 is in a turn-on state.

The control module 90 outputs a low level signal to the second transistor Q2 through the fourth resistor R4, the second transistor Q2 enters a cut-off state, the first transistor Q1 enters a cut-off state, and the switch submodule 740 is in a disconnected state.

Therefore, the control module 90 can control the on/off of the switch submodule 740 by outputting signals with different levels. It should be noted that the high level signal and the low level signal output by the control module 90 are determined based on the turn-on voltage of the second transistor Q2. Taking the second transistor triode Q2 as a silicon transistor, the turn-on voltage of the silicon transistor is 0.7V, and the amplitude of the high level signal may be a voltage value greater than or equal to 0.7V, for example, the amplitude of the high level signal is 1V; the amplitude of the low-level signal may be a voltage value less than 0.7V, for example, the amplitude of the low-level signal is 0V.

In some embodiments, the first resistor R1 has a resistance of 5 Ω, the second resistor R2 has a resistance of 10k Ω, the third resistor R3 has a resistance of 1k Ω, the fourth resistor R4 has a resistance of 1k Ω, and the output voltage of the power sub-module 730 is 5V. Under the condition that the second transistor Q2 enters the conducting state, the voltage across the second resistor R2 is 4.54V, which is much larger than the turn-on voltage of the first transistor Q1, and at this time, the first transistor Q1 enters the conducting state. In some embodiments, the first transistor Q1 is a silicon transistor, and the corresponding turn-on voltage is 0.7V, and in some embodiments, the first transistor Q1 is a germanium transistor, and the corresponding turn-on voltage is 0.3V.

It should be noted that the circuit structure of the switch submodule 740 shown in fig. 4 is only schematic, and the first Transistor triode Q1 and the second Transistor triode Q2 may be replaced by other power electronic devices with a switching function, such as Metal-Oxide-Semiconductor Field-Effect transistors (MOSFETs), insulated Gate Bipolar Transistors (IGBTs), etc., and the present embodiment is not particularly limited.

In some embodiments, the switch submodule 740 may also be a relay switch including a switch module and a control module, wherein the switch module is connected between the voltage detection submodule 750 and the power supply submodule 730 and electrically connected with the control module. The control module is connected to the control module 90, and when the control module 90 outputs a trigger signal to the control module, the control module controls the switch module to be turned on. Specifically, the relay switch may be an electromagnetic relay, an inductive relay, an electrodynamic relay, an electronic relay, or the like, and the embodiment is not particularly limited.

The power sub-module 730 includes a voltage source 7310, a fifth resistor R5, and a capacitor C0. The voltage source 7310 is a dc voltage source, and specifically, the voltage amplitude of the voltage source may be 5V. The fifth resistor R5 is connected in series between the voltage source 7310 and the first resistor R1. One end of the capacitor C0 is connected to the common connection end of the first resistor R1 and the fifth resistor R5, and the other end is grounded. Therefore, when the voltage source 7310 is in a power-on state, the capacitor C0 is charged through the fifth resistor R5. Specifically, under the condition that the resistance value of the fifth resistor R5 is 10k Ω and the capacitance value of the capacitor C0 is 100uF, the capacitor C0 can complete the charging operation within 12.5 ms. Subsequently, when the switch submodule 740 is in a conducting state, the capacitor C0 discharges to the detection circuit 340. The present embodiment does not limit the specific type of the capacitor C0. In the embodiment shown in fig. 4, the capacitor C0 is an electrolytic capacitor, and the capacitance of the electrolytic capacitor is 100uF.

Referring to fig. 3 again, in some embodiments, the detection circuit 340 includes an isolation transformer unit 3420, and the primary side of the isolation transformer unit 3420 is electrically connected to two ends of the fuse circuit 320. The secondary side of the isolation transformer module 3420 is electrically connected to two ends of the responder 520, and is connected in parallel to the first detection port 710 and the second detection port 720. The isolation transformer module 3420 is used to improve the anti-interference performance of the open circuit detection module 70, i.e., suppress electromagnetic interference in the short circuit protection circuit 100. In addition, the external load circuit is usually a high voltage circuit, the open circuit detection module 70 is a low voltage circuit, and the isolation transformer unit 3420 is connected between the external load circuit and the open circuit detection module 70, so that the effect of high and low voltage isolation can be achieved, and the use safety of the open circuit detection module 70 is ensured. Specifically, the isolation transformer module 3420 may be an isolation transformer, and the embodiment of the present application does not limit the type and hardware parameters of the isolation transformer.

A specific implementation of the control module 90 determining whether the detection circuit 340 is in the open state based on the port voltage is described herein with reference to fig. 3 and 4. As an embodiment, the control module 90 stores a fault mapping table, where the fault mapping table represents a mapping relationship between a value of the port voltage and whether the detection circuit 340 is in an open circuit state. The control module 90 can determine whether the detection circuit 340 is in the open circuit state by looking up the fault mapping table when the port voltage is obtained.

Specifically, under the condition that the detection circuit 340 is not in the open-circuit state, the line connection between the fuse circuit 320 and the primary side of the isolation transformer unit 3420 is normal at this time, taking the fuse circuit 320 as a thermal fuse as an example, the resistance of the thermal fuse is about 10u Ω, and the primary side of the isolation transformer unit 3420 is equivalent to short circuit at this time, which results in low impedance of the secondary side of the isolation transformer unit 3420. Specifically, the secondary impedance is approximately equal to 1 Ω, i.e., the equivalent resistance of the detection circuit 340 is 1 Ω. At this time, the capacitor C0 discharges to the detection circuit 340, and the port voltage detected by the voltage detection sub-module 750 is approximately 0.83V when the resistance value of the first resistor R1 is 5 Ω and the tube voltage drop of the first transistor Q1 is ignored.

In the case where the detection circuit 340 is in the open state, the line connection between the fuse circuit 320 and the primary side of the isolation transformer unit 3420 is open at this time, which results in a large secondary impedance of the isolation transformer unit 3420. Specifically, the secondary impedance is approximately equal to 50 Ω, that is, the equivalent resistance of the detection circuit 340 is 50 Ω. At this time, the capacitor C0 discharges to the detection circuit 340, and similarly, when the resistance value of the first resistor R1 is 5 Ω and the tube voltage drop of the first transistor Q1 is ignored, the port voltage detected by the voltage detection sub-module 750 is approximately 4.5V.

Therefore, the control module 90 can determine whether the detection circuit 340 is in the open state according to the magnitude of the port voltage. Specifically, the control module 90 may have a structure of a control chip, an integrated circuit board, and the like, and the embodiment is not particularly limited. In some embodiments, the short-circuit protection circuit 100 further comprises an alarm module (not shown) electrically connected to the control module 90 for sending an alarm signal when the detection circuit 340 is in the open state. The alarm module may be an indicator light, a speaker, etc., and the present application is not limited specifically. In some embodiments, the short-circuit protection circuit 100 further includes a communication module (not shown in the figure), which is electrically connected to the control module 90 and is communicatively connected to an external communication device (e.g., a mobile terminal, a vehicle center console) for sending a notification message when the detection circuit 340 is in the open state. Wherein the control module 90 is further configured to: and if the detection circuit is in an open circuit state, sending an alarm instruction.

In some embodiments, referring to fig. 5, the short-circuit protection circuit 100 further includes a second driving module 40. The second driving module 40 is electrically connected to the responder 520, and the second driving module 40 may be a driving control chip, an integrated circuit board, or the like. In one aspect, the second driving module 40 is electrically connected to a signal detection device (e.g., a voltage detection device) in the external load circuit, and is configured to obtain a detection signal sent by the signal detection device. On the other hand, the second driving module 40 is configured to send a trigger current to the responder 520 in case that the detection signal is abnormal, that is, in case that it is determined that the external load circuit is short-circuited based on the detection signal. The trigger current is a current that can make the responder 520 enter a trigger state, that is, the trigger current generated by the second driving module 40 triggers the circuit breaker 540 through the responder 520 to break a circuit between the first connection terminal 10 and the second connection terminal 20. Specifically, the magnitude of the trigger current is determined by the particular model of the shutdown module 50, which is 1.75A for example. Therefore, the short-circuit protection circuit 100 in the present embodiment is provided with dual protection measures (i.e., fuse circuit protection and second drive module protection), so that the short-circuit protection is safer and more reliable. Even if the second driving module 40 fails, the branch where the external load circuit is located can be cut off by blowing the short circuit 320 to trigger the responder 520, so that the situation that the external load circuit is damaged due to out-of-control short circuit is avoided.

In some embodiments, the second driving module 40 is provided with a first output end 410 and a second output end 420, and the second driving module 40 is electrically connected to the responder 520 through the first output end 410 and the second output end 420. In this embodiment, the short-circuit protection circuit 100 further includes a first filter capacitor C1 and a second filter capacitor C2, wherein the first output terminal 7410 is grounded through the first filter capacitor C1, the second output terminal 7420 is grounded through the second filter capacitor C2, and the first filter capacitor C1 and the second filter capacitor C2 improve the stability of the second driving module 40 during operation.

In some embodiments, the short-circuit protection circuit 100 further includes a first connector 60 and a second connector 80, wherein the disconnection detection module 70 is connected to the responder 520 through the first connector 60 and the second connector 80 is connected to the responder 520 through the second connector 80. Referring to fig. 6, the first connector 60 may be a twisted pair harness, one end of which is connected in parallel to two ends of the responder 520, and the other end of which is connected to the first detection port 710 and the second detection port 720 of the disconnection detection module 70, respectively. Each twisted wire bundle of the twisted wire bundles can be regarded as formed by serially connecting a wire inductance and a wire resistance. Specifically, in the embodiment shown in fig. 6, one end of the first inductor L1 and the sixth resistor R6 connected in series is connected to one end of the responder 520, and the other end is connected to the first detection port 710. Similarly, the second inductor L2 and the seventh resistor R7 are connected in series, and one end thereof is connected to the other end of the responder 520, and the other end thereof is connected to the second detection port 720. In the embodiment of the present application, the first connector 60 is detachably connected to the responder 520 and the disconnection detecting module 70, respectively, so that a serviceman can easily detach, repair and replace the first connector 60 and the disconnection detecting module 70 when the first connector 60 or the disconnection detecting module 70 malfunctions.

In some embodiments, the length of the first connector 60 is greater than or equal to 4 meters. Therefore, the disconnection detecting module 70 and the detecting circuit 340 at the two ends of the first connector 60 can be respectively disposed at different positions of the power battery pack 230, so that the overall circuit layout of the short-circuit protection circuit 100 is more flexible.

Likewise, the second connector 80 may be a twisted pair bundle, one end of which is connected in parallel to both ends of the responder 520, and the other end of which is connected to the first output terminal 410 and the second output terminal 420 of the second driving module 40, respectively. Each twisted wire bundle of the twisted wire bundles can be regarded as formed by serially connecting a wire inductance and a wire resistance. Specifically, in the embodiment shown in fig. 6, one end of the third inductor L3 and the eighth resistor R8, which are connected in series, is connected to one end of the responder 520, and the other end is connected to the first output terminal 410. Similarly, the fourth inductor L4 and the ninth resistor R9 are connected in series, and one end thereof is connected to the other end of the responder 520, and the other end thereof is connected to the second output terminal 420. In the embodiment of the present application, the second connector 80 is detachably connected to the responder 520 and the second driving module 40, respectively, and thus, when the second connector 80 or the second driving module 40 malfunctions, a serviceman can easily detach, repair, and replace the second connector 80 and the second driving module 40.

In some embodiments, the length of the second connector 80 is greater than or equal to 4 meters. Therefore, the disconnection detecting module 70 and the detecting circuit 340 at two ends of the second connector 80 can be disposed at different positions of the power battery pack 230, so that the overall circuit layout of the short-circuit protection circuit 100 is more flexible.

In some embodiments, the detection circuit 340 further includes a rectifying unit 3440, an input terminal of the rectifying unit 3440 is connected to two terminals of the fuse circuit 320 through the isolation transforming unit 3420, and an output terminal of the rectifying unit 3440 is connected to two terminals of the second driving module 40. Specifically, the first output terminal 410 and the second output terminal 420 of the second driving module 40 are respectively connected to the output terminals of the rectification unit 3440. One end of the responder 520 is connected to a common end of the positive output end of the rectifying unit 3440 and the first output end 410, and the other end of the responder 520 is connected to a common end of the negative output end of the rectifying unit 3440 and the second output end 420.

Since the fuse circuit 320 and the second driving module 40 are both connected in parallel to both ends of the responder 520, when the fuse circuit 320 is in a fuse state, a pulse voltage signal is output to the second driving module 40, the polarity of the pulse voltage signal is determined by the current direction in the branch where the external load circuit is located, and under a normal condition, the polarity of the pulse voltage signal is consistent with the polarity of the output voltage of the second driving module 40. However, once the external load circuit is reversely connected between the first connection terminal 10 and the second connection terminal 20, the fuse circuit 320 outputs the voltage signal to the second driving module 40 as a reverse pulse voltage signal, and if the reverse pulse voltage signal is directly applied to the second driving module 40, the second driving module 40 may be damaged. In this embodiment, the rectifying unit 3440 is connected between the fuse circuit 320 and the second driving module 40, and the rectifying unit 3440 can correct the polarity of the reverse pulse voltage signal, so that the corrected polarity of the reverse pulse voltage signal is consistent with the polarity of the voltage signal output by the second driving module 40, thereby preventing the reverse pulse voltage signal from damaging the second driving module 40. Specifically, the rectifying unit 3440 may be a rectifying bridge.

In some embodiments, the detection circuit 340 further includes a voltage regulator 3460, a positive terminal of the voltage regulator 3460 is connected to the first output terminal 410, and a negative terminal of the voltage regulator 3460 is connected to a positive output terminal of the rectification module 3440. The voltage regulator tube 3460 is used for avoiding the occurrence of the problem that the trigger current is shunted by the rectifying unit 3440 due to the reverse connection of the second connector 80 when the second driving module 40 sends the trigger current to the responder 520 through the second connector 80. Taking the second connector 80 as a twisted pair harness as an example, the problem of reverse stitch may occur during the fabrication of the twisted pair harness. It should be noted that, in the embodiment of the present application, the first output terminal 410 is a positive terminal, that is, a trigger current flowing terminal. When the second connector 80 is not connected in a reverse direction, when the trigger current flowing from the first output terminal 410 passes through the positive output terminal of the rectifying unit 3440, the rectifying unit 3440 is turned off in a reverse direction, and the trigger current flows to the responder 520, so that the responder 520 is in a trigger state. However, in the case that the second connector 80 is reversely connected, the trigger current flowing from the first output terminal 410 flows to the negative output terminal of the rectifying unit 3440, and at this time, the rectifying unit 3440 is conducted in the forward direction, so that the trigger current does not flow to the responder 520, that is, the second driving module 40 cannot control the responder 520 to enter the trigger state.

In this embodiment, by adding the voltage regulator 3460 to the detection circuit 340, when the detection voltage generated when the fuse circuit 320 is blown is applied to both ends of the voltage regulator 3460, the voltage regulator 3460 is in a reverse breakdown state. Therefore, when the second connector 80 is reversely connected, when the trigger current flowing from the rectifying unit 3440 passes through the zener diode 3460, the voltage across the zener diode 3460 is smaller than the critical value, and at this time, the zener diode 3460 is in the reverse cut-off state. Therefore, the trigger current flows to the responder 520, so that the responder 520 is in a trigger state, and the normal operation of the responder 520 is ensured. In some embodiments, the voltage regulator tube 3460 has a rated voltage of 3.9V and a rated power of 1W, and the embodiment of the present application does not limit the type of the voltage regulator tube 3460 and the hardware parameters.

In some embodiments, the detection circuit 340 may further include a suppression unit 3480, the suppression unit 3480 being connected in parallel to the first output terminal 410 and the second output terminal 420. The suppressing unit 3480 is configured to suppress the spike voltage signal generated when the responder 520 is in the trigger state, so as to avoid the second driving module 40 from being damaged due to an excessively large value of the spike voltage signal. Referring to fig. 7, in some embodiments, the suppression unit 3480 includes a transient suppressor 3482 and a suppression capacitor 3484, and the transient suppressor 3482 and the suppression capacitor 3484 are respectively connected in parallel to the first output terminal 410 and the second output terminal 420. Illustratively, the transient suppressor 3482 has a rated voltage of 24V and a rated power of 200W, and the present embodiment does not limit the models and hardware parameters of the transient suppressor 3482 and the suppression capacitor 3484. In addition, the suppression capacitor 3484 can also filter out high frequency impact between the first output terminal 410 and the second output terminal 420, thereby ensuring the service life of the second driving module 40. In other embodiments, the suppression unit 3480 may include only the transient suppressor 3482, or may include only the suppression capacitance 3484.

The embodiment of the application discloses a short-circuit protection circuit. The short-circuit protection circuit is connected with an external load circuit through a first connecting end and a second connecting end, a fusing circuit and a circuit breaker are connected in series between the first connecting end and the second connecting end, and the circuit breaker is connected with the responder. The responder is connected to the detection circuits connected in parallel at two ends of the fusing circuit, when the fusing circuit is in a fusing state, the detection voltage at two ends of the fusing circuit is greater than a specified voltage, and the responder triggers the circuit breaker to cut off a circuit between the first connecting end and the second connecting end. Therefore, under the condition that the external load circuit is short-circuited, the fusing circuit is fused to trigger the breaker to cut off the external load circuit, namely, the circuit breaking module can realize the quick cut-off of the external load circuit without being connected with an external driver, and the hardware cost of the circuit is saved.

In addition, the short-circuit protection circuit in the application further comprises a circuit breaking detection module and a control module, wherein the circuit breaking detection module is connected to two ends of the detection circuit in parallel. The control module is connected to the disconnection detection module and judges whether the detection circuit is in a disconnection state or not based on the port voltage acquired by the disconnection detection module, namely, whether a line between the fuse circuit and the responder is disconnected or not is judged. Therefore, the short-circuit protection circuit in the application also has a function of detecting the open circuit, the condition that the circuit between the fusing circuit and the responder is broken and the fusing circuit cannot be triggered to cut off an external load circuit after being fused is avoided, and the reliability of connection between the fusing circuit and the responder is ensured.

In the present specification, certain terms are used throughout the description and claims to refer to particular components. As one skilled in the art will appreciate, manufacturers may refer to a component by different names. The specification and claims do not intend to distinguish between components that differ in name but not function. In the following description and in the claims, the terms "include" and "comprise" are used in an open-ended fashion, and thus should be interpreted to mean "include, but not limited to,"; "substantially" means that a person skilled in the art can solve the technical problem within a certain error range and basically achieve the technical effect.

In the description of the present application, it is to be understood that the terms "upper", "lower", "front", "rear", "left", "right", "inside", and the like indicate orientations or positional relationships based on those shown in the drawings, and are simply used for convenience of description of the present application, and do not indicate or imply that the referred devices or elements must have a specific orientation, be constructed and operated in a specific orientation, and thus, should not be construed as limiting the present application.

In this application, the terms "mounted," "connected," "secured," and the like are to be construed broadly unless otherwise specifically stated or limited. For example, the connection can be fixed, detachable or integrated; can be mechanically or electrically connected; they may be directly connected or indirectly connected through an intermediate member, or they may be connected through the inside of two members or they may be merely surface-contacting. The specific meaning of the above terms in the present application can be understood by those of ordinary skill in the art as appropriate.

In the description of the present specification, reference to the description of "one embodiment," "some embodiments," "an example," "a specific example," or "some examples" or the like means that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the present application. In this specification, the schematic representations of the terms used above are not necessarily intended to refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples. Moreover, various embodiments or examples and features of various embodiments or examples described in this specification can be combined and combined by one skilled in the art without being mutually inconsistent.

Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or to implicitly indicate the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature. In the description of the present application, "plurality" means at least two, e.g., two, three, etc., unless specifically limited otherwise.

Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present application, and not to limit the same; although the present application has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; such modifications and substitutions do not depart from the spirit and scope of the corresponding technical solutions in the embodiments of the present application.

Claims

1. A short-circuit protection circuit having a first connection terminal and a second connection terminal for connecting an external load circuit, the short-circuit protection circuit comprising:

the first driving module comprises a fusing circuit and a detection circuit, and the fusing circuit is connected between the first connecting end and the second connecting end in series; the detection circuit is connected in parallel at two ends of the fusing circuit and used for acquiring detection voltages at two ends of the fusing circuit;

the circuit breaker and the fusing circuit are connected in series between the first connecting end and the second connecting end; the responder is connected to the detection circuit and is connected with the circuit breaker, and the responder is used for triggering the circuit breaker to cut off the circuit between the first connecting end and the second connecting end under the condition that the detection voltage is greater than the specified voltage;

the circuit breaking detection module is provided with a first detection port and a second detection port, and the first detection port and the second detection port are connected to two ends of the detection circuit in parallel; and

a control module connected to the open circuit detection module and configured to: and acquiring port voltages of the first detection port and the second detection port, and judging whether the detection circuit is in an open circuit state or not based on the port voltages.

2. The short-circuit protection circuit of claim 1, wherein the open-circuit detection module comprises a power supply sub-module, a switch sub-module, and a voltage detection sub-module;

the voltage detection submodule is connected in parallel to two ends of the first detection port and the second detection port and is connected to the control module;

the switch submodule is connected between the voltage detection submodule and the power supply submodule, and is connected to the control module, which is further configured to: sending a trigger signal to the switch submodule, wherein the trigger signal is used for triggering the switch submodule to enter a conducting state; and under the condition that the switch submodule is in a conducting state, acquiring port voltages of the first detection port and the second detection port.

3. The short-circuit protection circuit of claim 2, wherein the switching submodule comprises a first transistor, a second transistor, a first resistor, a second resistor, a third resistor, and a fourth resistor;

the first transistor triode is a PNP transistor, and an emitting electrode of the first transistor triode is connected to the power supply submodule through the first resistor; a collector of the first transistor is connected to the first detection port; the base electrode of the first crystal triode is connected with the collector electrode of the second crystal triode through the third resistor;

the second crystal triode is an NPN type crystal triode, and an emitting electrode of the second crystal triode is connected to the second detection port and grounded; the base electrode of the second crystal triode is connected to the control module through the fourth resistor;

one end of the second resistor is connected to a common connecting end of the first resistor and the emitter of the first transistor; the other end of the first resistor is connected with the base electrode of the first transistor and the common connecting end of the third resistor.

4. The short-circuit protection circuit of claim 3, wherein the power supply sub-module comprises a voltage supply, a fifth resistor and a capacitor;

the fifth resistor is connected in series between the voltage source and the first resistor;

one end of the capacitor is connected to the common connection end of the first resistor and the fifth resistor, and the other end of the capacitor is grounded.

5. The short-circuit protection circuit according to any one of claims 1 to 4, wherein the detection circuit comprises an isolation transformer unit, and a primary side of the isolation transformer unit is electrically connected to two ends of the fuse circuit; and the secondary side of the isolation transformation module is electrically connected to two ends of the responder and is connected with the first detection port and the second detection port in parallel.

6. The short-circuit protection circuit according to any one of claims 1 to 4, further comprising a second driving module;

the second driving module is electrically connected to the responder and configured to generate a trigger current to trigger the circuit breaker to break the circuit between the first connection end and the second connection end through the responder in case of a short circuit of the external load circuit.

7. The short-circuit protection circuit of claim 6, wherein the detection circuit further comprises a rectifying unit, an input end of the rectifying unit is connected to two ends of the fuse circuit, and an output end of the rectifying unit is connected to two ends of the second driving module.

8. The short-circuit protection circuit of claim 7, wherein the second driving module comprises a first output terminal and a second output terminal, and the first output terminal and the second output terminal are respectively connected to the output terminals of the rectifying unit; one end of the responder is connected to a common end of the positive output end and the first output end of the rectifying unit, and the other end of the responder is connected to a common end of the negative output end and the second output end of the rectifying unit;

the detection circuit further comprises a voltage-stabilizing tube, wherein the positive end of the voltage-stabilizing tube is connected to the first output end, and the negative end of the voltage-stabilizing tube is connected to the positive output end of the rectifier module.

9. The short-circuit protection circuit of claim 8, wherein the detection circuit further comprises a suppression unit connected in parallel to the first output terminal and the second output terminal; the suppression unit comprises a transient suppressor or/and a suppression capacitor.

10. A power battery pack, comprising:

a battery pack; and

the short-circuit protection circuit of any one of claims 1 to 9, the first connection terminal and the second connection terminal of the short-circuit protection circuit being connected to the positive electrode and the negative electrode of the battery pack, respectively.

11. A vehicle, characterized by comprising:

a housing; and

the power cell package of claim 10, said power cell package disposed within said housing.