A bleed circuit

Abstract

The application discloses a kind of bleed circuits, for battery management system, battery management system includes the protection circuit being connected to output, bleed circuit includes: switch module, between output and battery, for controlling the communication and disconnection of output and battery;Discharge module, connect output, for enabling state by discharging bleed protection circuit voltage;Control module is connected with switch module and discharge module respectively, for when protection circuit needs to be relieved, control switch module is disconnected, and control discharge module enters enabling state.Compared with prior art, the application is driven by control module to disconnect switch module and control discharge module to discharge protection circuit, to realize the automatic power-down after battery management system shutdown.

Description

Technical Field

[0001] This application relates to the field of energy storage equipment technology, and in particular to a discharge circuit. Background Technology

[0002] Battery Management System (BMS) technology is widely used in fields such as communication power supply and residential energy storage. Inside the battery management system, there is usually a protection circuit with multiple capacitors connected in parallel. These capacitors are charged to the working voltage after being powered on. When the system is powered off or offline, due to the high resistance isolation of the bus caused by anti-reverse devices / relays, the capacitors may still have a high voltage remaining for a long time.

[0003] This residual voltage can pose risks such as sparking, electric shock, and component breakdown during assembly, handling, and maintenance, affecting the safety of personnel and equipment. Therefore, there is an urgent need for a discharge circuit capable of releasing residual electrical charge in the protection circuit. Utility Model Content

[0004] One objective of this application is to provide a discharge circuit that addresses the technical problem in the prior art where the protection circuit retains charge after the battery management system is powered off, leading to sparking and electric shock.

[0005] To achieve the above objectives, this application provides a discharge circuit for a battery management system. The battery management system includes a protection circuit connected to an output port. The discharge circuit includes: a switch module connected between the output port and the battery for controlling the connection and disconnection between the output port and the battery; a discharge module connected to the output port for discharging the voltage of the protection circuit through discharge when in the enabled state; and a control module connected to the switch module and the discharge module respectively for controlling the switch module to disconnect and controlling the discharge module to enter the enabled state when the protection circuit needs to discharge voltage.

[0006] The discharge circuit provided in this application realizes the automatic discharge of residual power in the protection circuit. When the control module determines that the protection circuit needs to be discharged, it first controls the switch module to disconnect, so as to achieve electrical isolation between the protection circuit side and the battery side, and avoid reverse charging and discharging interference to the battery during the discharge process. At the same time, the control module controls the discharge module to enter the enabled state, and discharges the residual voltage on the protection circuit.

[0007] Existing technologies employ two main discharge methods: manual discharge using external temporary fixtures, which is complex and inconsistent; and setting a constantly operating resistor in the battery management system, which results in continuous standby power consumption and extended power-off time. In contrast, this application utilizes a control module to drive a switching module to disconnect and control a discharge module to discharge the protection circuit, achieving automatic power-off after the battery management system is shut down. This approach quickly and reliably discharges the protection circuit voltage to a safe range during shutdown, reducing the risk of accidental arcing and electric shock caused by residual voltage in the protection circuit. Furthermore, the discharge module only activates and discharges when needed, avoiding static energy consumption caused by constantly operating discharge. This reduces manual intervention while improving the consistency and efficiency of production and maintenance.

[0008] According to one embodiment of this application, the output port includes a positive output port and a negative output port, the discharge module includes a first switching transistor and a discharge load, the first switching transistor and the discharge load are connected in series between the positive output port and the negative output port, and the controlled terminal of the first switching transistor is connected to the control module.

[0009] According to one embodiment of this application, the discharge circuit further includes a driving module, which is connected between the control module and the controlled terminal of the discharge module, and is used to receive signals from the control module and control the discharge module to enter the enabled state.

[0010] According to one embodiment of this application, the drive module includes a second switch connected between the controlled terminal of the discharge module and the negative terminal of the battery, and the controlled terminal of the second switch is connected to the control module.

[0011] According to one embodiment of this application, the driving module further includes a first current limiting filter circuit connected between the control module and the second switching transistor. The first current limiting filter circuit is used to receive the signal from the control module, perform current limiting processing, and output the filtered signal to the second switching transistor.

[0012] According to one embodiment of this application, the discharge circuit further includes a first switching transistor, a second switching transistor, a discharge load, a first current-limiting resistor, a first voltage-dividing resistor, a second voltage-dividing resistor, a third voltage-dividing resistor, and a first filter capacitor. The output port includes a positive output port and a negative output port. The first switching transistor is a first transistor, and the second switching transistor is a second transistor. The emitter of the first transistor is connected to the positive output port. The discharge load is connected between the collector of the first transistor and the negative output port. The first voltage-dividing resistor is connected between the emitter and base of the first transistor. The second voltage-dividing resistor is connected between the base of the first transistor and the collector of the second transistor. The emitter of the second transistor is connected to the negative terminal of the battery, and the collector of the second transistor is connected to the base of the first transistor. The third voltage-dividing resistor and the first filter capacitor are connected in parallel between the emitter and base of the second transistor. The first current-limiting resistor is connected between the base of the second transistor and the control module.

[0013] According to one embodiment of this application, the discharge circuit further includes a voltage detection module, which is connected to the output port and the control module respectively. The voltage detection module is used to obtain the detection voltage of the protection circuit and output it to the control module, so that the control module controls the discharge module to exit the enabled state when the detection voltage drops to the discharge threshold voltage.

[0014] In this embodiment, the voltage detection module is connected to the output port to acquire the detection voltage of the protection circuit in real time and output it to the control module. The control module compares the voltage with the preset discharge threshold voltage. When the detection voltage is still higher than the threshold, the control module does not perform any control action, and the discharge module remains in the enabled state to continue discharging. When the detection voltage drops to the discharge threshold voltage, the control module controls the discharge module to exit the enabled state, thereby ending the discharge process and preventing the circuit from being over-discharged.

[0015] The coordinated operation of the voltage detection module, control module, and discharge module enables the discharge circuit to automatically stop discharging after reaching the target voltage, avoiding over-discharge or unnecessary energy loss of the energy storage components in the protection circuit due to continued discharge. This ensures the controllability and consistency of the final residual voltage of the protection circuit, facilitating the rapid restart of the battery management system next time.

[0016] According to one embodiment of this application, the output port includes a positive output port and a negative output port. The voltage detection module includes: a voltage sampling unit connected between the positive output port and the negative output port, used to sample the voltage of the protection circuit and output the corresponding detection voltage; and an amplifier circuit connected between the voltage sampling unit and the control module, used to amplify the detection voltage output by the voltage sampling unit and output it to the control module.

[0017] According to one embodiment of this application, the discharge module includes a first switching transistor and a discharge load, and a voltage sampling unit and a discharge load multiplexed voltage relief resistor; the first switching transistor and the voltage relief resistor are connected in series between the positive output port and the negative output port, and the controlled terminal of the first switching transistor is connected to the control module.

[0018] According to one embodiment of this application, the amplifier circuit includes an operational amplifier, the first input terminal and the second input terminal of the operational amplifier are respectively connected to the two ends of a voltage relief resistor, and the output terminal of the operational amplifier is connected to a control module.

[0019] According to one embodiment of this application, the voltage detection module further includes: a second current-limiting filter circuit, connected to the voltage sampling unit and the amplifier circuit, used to perform current-limiting processing on the detection voltage output by the voltage sampling unit and to input the filtered voltage into the amplifier circuit; and an output filter circuit, connected to the amplifier circuit and the control module, used to perform filtering processing on the detection voltage amplified by the amplifier circuit and to input the filtered voltage into the control module.

[0020] According to one embodiment of this application, the second current-limiting filter circuit includes a second current-limiting resistor, a third current-limiting resistor, and a second filter capacitor. The second current-limiting resistor is connected in series between the first terminal of the voltage sampling unit and the first input terminal of the operational amplifier, and the third current-limiting resistor is connected in series between the second terminal of the voltage sampling unit and the second input terminal of the operational amplifier. The second filter capacitor is connected between the first input terminal and the second input terminal of the operational amplifier. And / or the output filter circuit includes a fourth voltage-dividing resistor and a third filter capacitor. The first terminal of the fourth voltage-dividing resistor is connected to the output terminal of the operational amplifier, the second terminal of the fourth voltage-dividing resistor is connected to the control module, and the second terminal of the fourth voltage-dividing resistor is connected to the negative terminal of the battery via the third filter capacitor.

[0021] According to one embodiment of this application, the output port includes a positive output port and a negative output port, the protection circuit includes a first protection capacitor and / or a second protection capacitor, and the switching module includes a charging switch and / or a discharging switch; the positive output port is connected to the positive terminal of the battery, and the negative output port is connected to the negative terminal of the battery in sequence via the charging switch and the discharging switch; the controlled terminals of the charging switch and the discharging switch are connected to a control module for controlling the connection and disconnection between the output port and the battery; the first protection capacitor is connected between the positive output port and the negative output port, and the second protection capacitor is connected between the connection node of the charging switch and the discharging switch and the positive output port.

[0022] Other advantages, objectives and features of this application will be partly apparent from the description below, and partly understood by those skilled in the art through study and practice of this application. Attached Figure Description

[0023] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0024] Figure 1 This is a schematic diagram of an application scenario for the discharge circuit provided in the embodiments of this application; Figure 2 This is a schematic diagram of the circuit structure of the discharge circuit provided in the embodiment of this application.

[0025] Explanation of icon numbers: 101. Switching module; 102. Discharging module; 103. Control module; 104. Drive module; 105. Voltage detection module; 106. Battery; 107. Protection circuit; V+, positive output port; V-, negative output port; Q1, first switching transistor; Q2, second switching transistor; R0, voltage relief resistor; R1, first voltage divider resistor; R2, second voltage divider resistor; R3, third voltage divider resistor; R4, fourth voltage divider resistor; R5, first current limiting resistor; R6, second current limiting resistor; R7, third current limiting resistor; C1, first filter capacitor; C2, second filter capacitor; C3, third filter capacitor; U1, operational amplifier. Detailed Implementation

[0026] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of the embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0027] With the expansion of applications such as consumer power supplies and industrial energy storage, battery management systems (BMS) are used for centralized management of battery charging, discharging, balancing, and safety strategies. To suppress surges, ripple, and electromagnetic interference, BMS typically incorporates protection circuits including multiple protective capacitors. This results in the protective capacitors being charged to their operating voltage when the system is powered on; however, when the system is off-lined, undergoing maintenance, or being transported, the busbar exhibits high resistance due to relay disconnection, the unidirectional characteristics of anti-reverse devices, or other isolation factors. This makes it difficult for the voltage on the protective capacitors to naturally decay over a prolonged period, leading to safety hazards such as arcing, electric shock, and stress impacts on components during insertion, removal, handling, and maintenance.

[0028] To mitigate the aforementioned risks, existing solutions primarily employ two discharge methods: one involves manually discharging the battery by temporarily connecting a load using external tooling during factory testing or maintenance shutdown; the other involves connecting a normally-continuous power resistor in parallel with the bus inside the BMS, allowing the protection capacitor to self-discharge during shutdown. The former relies on manual operation and process consistency, resulting in low efficiency and a risk of omissions; while the latter, although capable of automatic power-off, suffers from continuous static power consumption due to the normally-continuous resistor during prolonged standby, potentially leading to battery over-discharge or affecting overall standby efficiency. Furthermore, increasing the resistance value to reduce power consumption significantly prolongs the power-off time, making it difficult to balance safety and energy efficiency goals.

[0029] To solve the above technical problems, please refer to Figure 1 and Figure 2 To address the aforementioned technical problems, this application provides a discharge circuit for a battery management system. The battery management system includes a protection circuit 107 connected to the output port. The discharge circuit includes: The switch module 101 is connected between the output port and the battery 106 and is used to control the connection and disconnection between the output port and the battery 106. The discharge module 102 is connected to the output port and is used to discharge the voltage of the protection circuit 107 when the circuit is enabled. The control module 103 is connected to the switch module 101 and the discharge module 102 respectively, and is used to control the switch module 101 to disconnect and control the discharge module 102 to enter the enabled state when the protection circuit 107 needs to release pressure.

[0030] The discharge circuit provided in this application realizes the automatic discharge of residual power in the protection circuit 107. When the control module 103 determines that the protection circuit 107 needs to be discharged, it first controls the switch module 101 to open, so as to achieve electrical isolation between the protection circuit 107 side and the battery 106 side, and avoid the discharge process from causing reverse charging and discharging interference to the battery 106. At the same time, the control module 103 controls the discharge module 102 to enter the enabled state, and discharges the residual voltage on the protection circuit 107.

[0031] In existing technologies, manual discharge using external temporary fixtures is complex and inconsistent. Setting a constantly connected resistor in the battery management system results in continuous standby power consumption and prolonged power-off time. Compared to these existing technologies, this application uses a control module 103 to drive the switch module 101 to disconnect and control the discharge module 102 to discharge the protection circuit 107, achieving automatic power-off after the battery management system is shut down. On the one hand, in shutdown scenarios, it can quickly and reliably discharge the voltage of the protection circuit 107 to a safe range, reducing the risk of accidental arcing and electric shock caused by residual voltage in the protection circuit 107. On the other hand, the discharge module 102 only starts and discharges when needed, avoiding static energy consumption caused by constantly connected discharge. This reduces manual intervention while improving the consistency and efficiency of production and maintenance.

[0032] It should be understood that Figure 1 This diagram illustrates an application scenario of the discharge circuit provided in this application. The battery and protection circuit shown are scenario features and are not protected by this application. The battery management system includes the protection circuit and the discharge circuit of this application, and is used to manage the charging and discharging of the battery.

[0033] According to one embodiment of this application, the output port includes a positive output port V+ and a negative output port V-. The discharge module 102 includes a first switch Q1 and a discharge load. The first switch Q1 and the discharge load are connected in series between the positive output port V+ and the negative output port V-. The controlled terminal of the first switch Q1 is connected to the control module 103.

[0034] In this embodiment, the first switch Q1 and the discharge load are connected in series between the positive output port V+ and the negative output port V-. The discharge module 102 directly faces the output port to discharge, resulting in a short path and a fixed impedance, which is beneficial for improving discharge efficiency. When voltage relief is not required, the first switch Q1 is turned off, and the discharge module 102 is in an inactive state, avoiding static power consumption and impact on the normal operating bus caused by constant discharge. When voltage relief is required, the control module 103 turns on the first switch Q1, and the discharge load discharges to the protection circuit 107 connected to the output port to eliminate residual voltage in the protection circuit 107.

[0035] According to one embodiment of this application, the discharge circuit further includes a driving module 104, which is connected between the control module 103 and the controlled terminal of the discharge module 102, and is used to receive signals from the control module 103 and control the discharge module 102 to enter the enabled state.

[0036] In this embodiment, a drive module 104 is provided between the control module 103 and the discharge module 102. This macroscopically increases the number of steps in the control link. By isolating the control module 103 and the discharge module 102, the drive margin and anti-interference capability of the discharge circuit under high-voltage bus or high-power discharge load can be improved, ensuring rapid switching. More specifically, the drive module 104 is connected to the controlled terminal of the first switching transistor Q1, facilitating the shaping and amplification of the voltage level or drive current at the controlled terminal of the first switching transistor Q1, which helps ensure reliable conduction of the first switching transistor Q1.

[0037] According to one embodiment of this application, the drive module 104 includes a second switch Q2 connected between the controlled terminal of the discharge module 102 and the negative terminal of the battery 106, and the controlled terminal of the second switch Q2 is connected to the control module 103.

[0038] A second switch Q2 is connected in series between the controlled terminal of the first switch Q1 and the negative terminal of the battery 106, realizing multi-level driving. The control module 103 drives the second switch Q2 to switch between conduction and turn-off, which can adjust the conduction and disconnection of the controlled terminal of the first switch and the negative terminal of the battery 106 accordingly. This not only separates the control side and the power side, reducing the current and voltage stress on the control port, but also pulls down the potential of the controlled terminal of the first switch Q1 more quickly, shortens the conduction setup time, reduces the transition area loss, and improves the determinism and anti-interference capability of the discharge action as a whole.

[0039] It should be understood that the negative terminal of battery 106 referred to in this application can also be replaced by the ground of the battery management system in practical applications.

[0040] According to one embodiment of this application, the driving module 104 further includes a first current limiting filter circuit connected between the control module 103 and the second switch Q2. The first current limiting filter circuit is used to receive the signal from the control module 103, perform current limiting processing, and output the filtered signal to the second switch Q2.

[0041] A first current-limiting filter circuit is added between the control module 103 and the second switch Q2. By limiting and filtering the signal output by the control module 103, transient spike currents can be limited and high-frequency noise and glitches can be suppressed from entering the second switch Q2, thereby avoiding false triggering caused by control line coupling interference or jitter. At the same time, current limiting can reduce the impact of transient charging and discharging of the controlled terminal of the second switch Q2 by the control module 103, improving the system's anti-interference capability and overall switching reliability.

[0042] To better illustrate the technical solution of this application, a specific circuit configuration is provided below and the preferred implementation logic of this embodiment is described by way of example. Those skilled in the art can make adjustments based on this according to actual working conditions.

[0043] The discharge circuit also includes a first switching transistor Q1, a second switching transistor Q2, a discharge load, a first current-limiting resistor R5, a first voltage-dividing resistor R1, a second voltage-dividing resistor R2, a third voltage-dividing resistor R3, and a first filter capacitor C1. The output ports include a positive output port V+ and a negative output port V-. The first switching transistor Q1 is a first transistor, and the second switching transistor Q2 is a second transistor. The emitter of the first transistor is connected to the positive output port V+, and the discharge load is connected between the collector of the first transistor and the negative output port V-. A voltage divider resistor R1 is connected between the emitter and base of the first transistor. A second voltage divider resistor R2 is connected between the base of the first transistor and the collector of the second transistor. The emitter of the second transistor is connected to the negative terminal of the battery 106, and the collector of the second transistor is connected to the base of the first transistor. A third voltage divider resistor R3 and a first filter capacitor C1 are connected in parallel between the emitter and base of the second transistor. A first current-limiting resistor R5 is connected between the base of the second transistor and the control module 103.

[0044] When discharge is required, the control module 103 sends a high-level signal, and the first filter capacitor C1 is charged first. Once the high-level signal continues until the first filter capacitor C1 is fully charged, it is considered an open circuit. The first current-limiting resistor R5 and the third voltage-dividing resistor R3 divide the voltage. The second transistor conducts through the voltage difference of the third voltage-dividing resistor R3 connected between its emitter and base. The first voltage-dividing resistor R1 and the second voltage-dividing resistor R2 are connected in series between the positive output port V+ and the negative terminal of the battery 106, and also divide the voltage. The first voltage-dividing resistor R1 conducts through the voltage drop of the first voltage-dividing resistor R1 connected between the emitter and base of the first transistor. The discharge module 102 enters the enabled state and discharges the voltage of the protection circuit 107. The configuration of the first filter capacitor C1 and the third voltage-dividing resistor R3 ensures that the signal is only transmitted after the high-level signal continues until the first filter capacitor C1 is fully charged, effectively filtering instantaneous peaks. The first current-limiting resistor R5 prevents the first and second transistors from being damaged by large current surges, improving the robustness of the discharge circuit.

[0045] According to one embodiment of this application, the discharge circuit further includes a voltage detection module 105, which is connected to the output port and the control module 103 respectively. It is used to obtain the detection voltage of the protection circuit 107 and output it to the control module 103, so that the control module 103 controls the discharge module 102 to exit the enabled state when the detection voltage drops to the discharge threshold voltage.

[0046] In this embodiment, the voltage detection module 105 is connected to the output port to acquire the detection voltage of the protection circuit 107 in real time and output it to the control module 103. The control module 103 compares the voltage with the preset discharge threshold voltage. When the detection voltage is still higher than the threshold, the control module 103 does not perform any control action, and the discharge module 102 remains in the enabled state to continue discharging. When the detection voltage drops to the discharge threshold voltage, the control module 103 controls the discharge module 102 to exit the enabled state, thereby ending the discharge process and preventing the circuit from being over-discharged.

[0047] The coordinated operation of the voltage detection module 105, control module 103, and discharge module 102 enables the discharge circuit to automatically stop discharging after reaching the target voltage, avoiding excessive discharge or unnecessary energy loss to the energy storage element in the protection circuit 107 due to continued discharge. This ensures the controllability and consistency of the final residual voltage of the protection circuit 107, facilitating the rapid start-up of the battery management system next time.

[0048] It should be understood that although a voltage detection module 105 is provided in this embodiment to prevent over-discharge of the protection circuit 107, it should not be interpreted that the absence of the voltage detection module 105 will necessarily cause over-discharge or slow startup when the discharge circuit is working. For example, some protection circuits 107 are passive circuits and do not include energy storage elements. Even without a detection module, they will automatically stop discharging after the capacitor is discharged due to the disappearance of the voltage difference. Alternatively, the protection circuit 107 of the battery management system does not operate during the initial power-on phase. By the time the protection circuit 107 is needed to function, it has already been fully charged. Therefore, whether or not the discharge is stopped in time will not affect the startup of the battery management system. In other words, with or without the voltage detection module 105, the discharge circuit of this application can achieve the technical effect of automatic power-off, and this should not be used to limit the scope of protection of this application.

[0049] According to one embodiment of this application, the output port includes a positive output port V+ and a negative output port V-. The voltage detection module 105 includes: a voltage sampling unit connected between the positive output port V+ and the negative output port V-, used to sample the voltage of the protection circuit 107 and output the corresponding detection voltage; and an amplification circuit connected between the voltage sampling unit and the control module 103, used to amplify the detection voltage output by the voltage sampling unit and output it to the control module 103.

[0050] The sampling unit is connected across the positive output port V+ and the negative output port V- to sample the voltage of the protection circuit 107 in the form of the residual current output during the discharge process, and outputs the corresponding detection voltage to the amplification circuit. The amplification circuit amplifies the detection voltage so that even a small detection voltage can be accurately identified, thereby reducing the resistance requirement of the sampling unit. The combination of the two ensures both detection accuracy and anti-interference, and allows the control module 103 to adopt an architecture with higher threshold accuracy and lower input bias, taking into account both low power consumption and reliability.

[0051] According to one embodiment of this application, the discharge module 102 includes a first switch Q1 and a discharge load, and a voltage sampling unit and a discharge load multiplexed relief resistor R0; the first switch Q1 and the relief resistor R0 are connected in series between the positive output port V+ and the negative output port V-, and the controlled terminal of the first switch Q1 is connected to the control module 103.

[0052] This embodiment achieves the unification of the discharge path and voltage detection path by reusing the voltage relief resistor R0: the first switch Q1 and the voltage relief resistor R0 are connected in series between the positive output port V+ and the negative output port V-. When the switch is closed, the voltage relief resistor R0 not only bears the discharge load to release the voltage of the protection circuit 107, but also forms the sampling signal for the amplification circuit to determine the sampling voltage with its voltage drop across its two ends. When the voltage drops to the discharge threshold, the control module 103 turns off the first switch Q1, and no current flows through the voltage relief resistor R0, so the discharge stops immediately. Reusing the voltage relief resistor R0 is beneficial for saving materials and area, simplifying the circuit, and reducing lead or shunt errors. Moreover, the sampling point and the discharge point are set in the same position, which makes the measurement and discharge more consistent.

[0053] According to one embodiment of this application, the amplifier circuit includes an operational amplifier U1, the first input terminal and the second input terminal of the operational amplifier U1 are respectively connected to the two ends of the voltage relief resistor R0, and the output terminal of the operational amplifier U1 is connected to the control module 103.

[0054] This embodiment provides a specific configuration of an amplifier circuit. The operational amplifier U1 is used to differentially amplify the voltage drop across the voltage relief resistor R0, and the specific small voltage value of the detected voltage is amplified into a level signal that the control module 103 can determine. This is beneficial for the qualitative assessment of the residual current state of the protection circuit 107, and facilitates timely control of the discharge module 102 to exit the enabled state after the discharge is completed.

[0055] According to one embodiment of this application, the voltage detection module 105 further includes: a second current-limiting filter circuit, connected to the voltage sampling unit and the amplifier circuit, used to perform current-limiting processing on the detection voltage output by the voltage sampling unit and to input the filtered voltage into the amplifier circuit; and an output filter circuit, connected to the amplifier circuit and the control module 103, used to perform filtering processing on the detection voltage amplified by the amplifier circuit and to input the filtered voltage into the control module 103.

[0056] The second current-limiting filter circuit and the output filter circuit, by filtering the signals of the input and output amplifier circuits, can limit transient peak currents and suppress high-frequency noise and glitches entering and exiting the amplifier circuits, thereby avoiding false triggering caused by control line coupling interference or jitter. At the same time, current limiting can reduce the impact of the control module 103 on the transient charging and discharging of the amplifier circuit, improving the system's anti-interference capability and overall switching reliability.

[0057] According to one embodiment of this application, the second current-limiting filter circuit includes a second current-limiting resistor R6, a third current-limiting resistor R7, and a second filter capacitor C2. The second current-limiting resistor R6 is connected in series between the first terminal of the voltage sampling unit and the first input terminal of the operational amplifier U1, and the third current-limiting resistor R7 is connected in series between the second terminal of the voltage sampling unit and the second input terminal of the operational amplifier U1. The second filter capacitor C2 is connected between the first input terminal and the second input terminal of the operational amplifier U1. And / or, the output filter circuit includes a fourth voltage-dividing resistor R4 and a third filter capacitor C3. The first terminal of the fourth voltage-dividing resistor R4 is connected to the output terminal of the operational amplifier U1, the second terminal of the fourth voltage-dividing resistor R4 is connected to the control module 103, and the second terminal of the fourth voltage-dividing resistor R4 is connected to the negative terminal of the battery 106 via the third filter capacitor C3.

[0058] This embodiment provides a specific circuit structure. The preferred implementation logic of this embodiment is described below by way of example, so that those skilled in the art can adjust and replace it according to actual working conditions.

[0059] On the input side of operational amplifier U1, the two ends of the voltage sampling unit are input to the first and second input terminals of operational amplifier U1 through the second current-limiting resistor R6 and the third current-limiting resistor R7, respectively. While suppressing sudden surges and input overcurrent, the two components, together with the second filter capacitor C2, form an RC low-pass network at the differential terminal, allowing only relatively smooth low-frequency components of operational amplifier U1, thereby filtering out instantaneous spikes and high-frequency noise in the detected voltage and reducing sampling distortion.

[0060] On the output side of operational amplifier U1, the output filter circuit further limits and removes spikes from the op-amp output. The fourth voltage divider resistor R4 provides necessary voltage division and current limiting, and together with the third filter capacitor C3, forms a single-ended RC low-pass filter to ground, which moderately passivates the signal at the control module 103 terminal, avoiding glitches and digital jitter.

[0061] According to one embodiment of this application, the output port includes a positive output port V+ and a negative output port V-. The protection circuit 107 includes a first protection capacitor and / or a second protection capacitor. The switch module 101 includes a charging switch and / or a discharging switch. The positive output port V+ is connected to the positive terminal of the battery 106, and the negative output port V- is connected to the negative terminal of the battery 106 in sequence via the charging switch and the discharging switch. The controlled terminals of the charging switch and the discharging switch are connected to the control module 103 for controlling the connection and disconnection of the output port and the battery 106. The first protection capacitor is connected between the positive output port V+ and the negative output port V-, and the second protection capacitor is connected between the connection node of the charging switch and the discharging switch and the positive output port V+.

[0062] This embodiment provides a specific component configuration for the protection circuit 107. The first protection capacitor provides a low-impedance, high-frequency bypass between the positive output port V+ and the negative output port V-, absorbing transient spikes caused by external load switching and / or cable inductive backlash, reducing port voltage ringing and electromagnetic radiation. The second protection capacitor clamps high-frequency disturbances at the switching nodes, mitigating the impact during switch on / off. This improves anti-interference capability, EMC performance, and switching reliability, while reducing device stress and the risk of false triggering.

[0063] It should be noted that all directional indications (such as up, down, left, right, front, back, etc.) in the embodiments of this application are only used to explain the relative positional relationship and movement of each component in a certain specific posture. If the specific posture changes, the directional indication will also change accordingly.

[0064] It should also be noted that when a component is referred to as being "fixed to" or "set on" another component, it can be directly on the other component or may be connected to an intermediary component. When a component is referred to as being "connected to" another component, it can be directly connected to the other component or indirectly connected to the other component through an intermediary component.

[0065] Furthermore, the use of terms such as "first" and "second" in this application is for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. Additionally, the technical solutions of the various embodiments can be combined with each other, but only on the basis of being achievable by those skilled in the art. When the combination of technical solutions is contradictory or impossible to implement, such a combination of technical solutions should be considered non-existent and not within the scope of protection claimed in this application.

[0066] The above are merely preferred embodiments of this application and do not limit the patent scope of this application. Any equivalent structural transformations made based on the design concept of this application and the contents of the specification and drawings of this application, or direct / indirect applications in other related technical fields, are included within the patent protection scope of this application.

Claims

1. A discharge circuit, characterized in that, A battery management system, the battery management system including a protection circuit connected to an output port, the discharge circuit including: A switch module is connected between the output port and the battery to control the connection and disconnection between the output port and the battery; A discharge module, connected to the output port, is used to discharge the voltage of the protection circuit when in the enabled state. The control module is connected to the switch module and the discharge module respectively, and is used to control the switch module to disconnect and control the discharge module to enter the enabled state when the protection circuit needs to release pressure.

2. The discharge circuit according to claim 1, characterized in that, The output port includes a positive output port and a negative output port. The discharge module includes a first switching transistor and a discharge load. The first switching transistor and the discharge load are connected in series between the positive output port and the negative output port. The controlled terminal of the first switching transistor is connected to the control module.

3. The discharge circuit according to claim 1, characterized in that, The discharge circuit further includes a drive module, which is connected between the control module and the controlled terminal of the discharge module, and is used to receive signals from the control module and control the discharge module to enter the enabled state.

4. The discharge circuit according to claim 3, characterized in that, The drive module includes a second switching transistor connected between the controlled terminal of the discharge module and the negative terminal of the battery, and the controlled terminal of the second switching transistor is connected to the control module.

5. The discharge circuit according to claim 4, characterized in that, The driving module further includes a first current limiting filter circuit connected between the control module and the second switching transistor. The first current limiting filter circuit is used to receive the signal from the control module, perform current limiting processing, and output the filtered signal to the second switching transistor.

6. The discharge circuit according to claim 1, characterized in that, The discharge circuit further includes a first switching transistor, a second switching transistor, a discharge load, a first current-limiting resistor, a first voltage-dividing resistor, a second voltage-dividing resistor, a third voltage-dividing resistor, and a first filter capacitor. The output port includes a positive output port and a negative output port. The first switching transistor is a first transistor, and the second switching transistor is a second transistor. The emitter of the first transistor is connected to the positive output port. The discharge load is connected between the collector of the first transistor and the negative output port. The first voltage-dividing resistor is connected between the emitter and base of the first transistor. The second voltage-dividing resistor is connected between the base of the first transistor and the collector of the second transistor. The emitter of the second transistor is connected to the negative terminal of the battery, and the collector of the second transistor is connected to the base of the first transistor. The third voltage-dividing resistor and the first filter capacitor are connected in parallel between the emitter and base of the second transistor. The first current-limiting resistor is connected between the base of the second transistor and the control module.

7. The discharge circuit according to any one of claims 1-6, characterized in that, The discharge circuit also includes a voltage detection module, which is connected to the output port and the control module respectively. The voltage detection module is used to obtain the detection voltage of the protection circuit and output it to the control module, so that the control module controls the discharge module to exit the enabled state when the detection voltage drops to the discharge threshold voltage.

8. The discharge circuit according to claim 7, characterized in that, The output port includes a positive output port and a negative output port, and the voltage detection module includes: A voltage sampling unit is connected between the positive output port and the negative output port, and is used to sample the voltage of the protection circuit and output the corresponding detection voltage; An amplifier circuit, connected between the voltage sampling unit and the control module, is used to amplify the detected voltage output by the voltage sampling unit and then output it to the control module.

9. The discharge circuit according to claim 8, characterized in that, The discharge module includes a first switching transistor and a discharge load. The voltage sampling unit and the discharge load share a voltage relief resistor. The first switching transistor and the voltage relief resistor are connected in series between the positive output port and the negative output port. The controlled terminal of the first switching transistor is connected to the control module.

10. The discharge circuit according to claim 9, characterized in that, The amplifier circuit includes an operational amplifier, the first input terminal and the second input terminal of the operational amplifier are respectively connected to the two ends of the voltage relief resistor, and the output terminal of the operational amplifier is connected to the control module.

11. The discharge circuit according to claim 8, characterized in that, The voltage detection module further includes: The second current-limiting filter circuit is connected to the voltage sampling unit and the amplifier circuit. It is used to perform current-limiting processing and filtering processing on the detected voltage output by the voltage sampling unit and then input it into the amplifier circuit. An output filter circuit is connected to the amplifier circuit and the control module, and is used to filter the detected voltage after it has been amplified by the amplifier circuit before inputting it into the control module.

12. The discharge circuit according to claim 11, characterized in that, The amplifier circuit includes an operational amplifier; The second current-limiting filter circuit includes a second current-limiting resistor, a third current-limiting resistor, and a second filter capacitor. The second current-limiting resistor is connected in series between the first terminal of the voltage sampling unit and the first input terminal of the operational amplifier, and the third current-limiting resistor is connected in series between the second terminal of the voltage sampling unit and the second input terminal of the operational amplifier. The second filter capacitor is connected between the first input terminal and the second input terminal of the operational amplifier; and / or The output filtering circuit includes a fourth voltage divider resistor and a third filter capacitor. The first end of the fourth voltage divider resistor is connected to the output terminal of the operational amplifier, the second end of the fourth voltage divider resistor is connected to the control module, and the second end of the fourth voltage divider resistor is connected to the negative terminal of the battery via the third filter capacitor.

13. The discharge circuit according to any one of claims 1-6, characterized in that, The output port includes a positive output port and a negative output port, the protection circuit includes a first protection capacitor and / or a second protection capacitor, and the switching module includes a charging switch and / or a discharging switch. The positive output port is connected to the positive terminal of the battery, and the negative output port is connected to the negative terminal of the battery in sequence via the charging switch and the discharging switch; the controlled terminals of the charging switch and the discharging switch are connected to the control module to control the connection and disconnection of the output port and the battery. The first protection capacitor is connected between the positive output port and the negative output port, and the second protection capacitor is connected between the connection node of the charging switch and the discharging switch and the positive output port.

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