A recoverable secondary protection circuit and control method

Abstract

The application relates to a recoverable secondary protection circuit and a control method, which comprise a battery module, a primary protection module, a state detection module, a control module and a secondary switch management module; a signal input end of the state detection module is used for detecting battery state data of a current loop; a second signal output end of the state detection module is connected with a detection signal input end of the control module; the secondary switch management module comprises a power MOS tube unit with a pair of tubes; the power MOS tube unit is connected in series in the current loop; a control signal output end of the control module is connected with a control signal input end of the secondary switch management module; the control module controls the secondary switch management module to be turned off; when the battery state data recovers to a preset safety range, the control module controls the secondary switch management module to be turned on; under the premise of ensuring the safety of the battery, the recoverability, controllability and multistage redundancy of the protection mechanism are realized, and the stability and service life of the overall system are improved.

Description

Technical Field

[0001] This application relates to the technical field of protection circuits, and in particular to a recoverable secondary protection circuit and control method. Background Technology

[0002] Currently, with the widespread use of power banks, laptops, and various battery-powered devices, users' requirements for battery system safety are constantly increasing. Especially with the gradual improvement of relevant standards, the battery's ability to protect itself under abnormal operating conditions has become a key indicator. To ensure safety, existing technologies typically incorporate multi-level protection structures in battery management systems. Secondary protection often utilizes fuses; when a serious battery abnormality occurs, the fuse melts, cutting off the current circuit and thus providing protection. However, once a fuse melts, it is irreversible, rendering the battery system unusable. This irreversible characteristic has significant shortcomings in practical applications: for some recoverable abnormal operating conditions, the battery system is still permanently disconnected after the protection is triggered, reducing product availability, increasing maintenance costs, and wasting resources. Summary of the Invention

[0003] To address the problem that existing protection circuits reduce product availability, increase maintenance costs, and waste resources, this application provides a recoverable secondary protection circuit and control method.

[0004] A recoverable secondary protection circuit includes a battery module, a primary protection module, a status detection module, a control module, and a secondary switch management module; The primary protection module is connected in series in the current loop of the battery module and is used to perform primary disconnection of the current loop when the battery module is in the first preset abnormal state. The signal input terminal of the status detection module is used to detect the battery status data of the current loop. The first signal output terminal of the status detection module is connected to the detection signal input terminal of the first-level protection module, and the second signal output terminal of the status detection module is connected to the detection signal input terminal of the control module. The secondary switch management module includes a power MOSFET unit with a pair structure. The power MOSFET unit is connected in series in the current loop and is located on the loop path of the primary protection module in the current loop. The control signal output terminal of the control module is connected to the control signal input terminal of the secondary switch management module; When the control module determines whether the battery module is in a second preset abnormal state based on the battery status data, or detects that the first-level protection module is in a failed state, the control module controls the second-level switch management module to perform a second-level shutdown, so as to bidirectionally cut off the current loop through the power MOSFET unit. When the battery status data recovers to the preset safety range, the control module controls the secondary switch management module to turn on, so as to restore the current loop of the battery module.

[0005] By adopting the above technical solution and setting up a hierarchical structure of a primary protection module and a secondary switch management module, the primary protection module performs initial cut-off under normal abnormal conditions, while the secondary switch management module performs bidirectional cut-off in case of severe abnormalities or failure of the primary protection module. This ensures safety while achieving the recoverability of protection actions, avoiding the problem of irreversibility after a traditional fuse blows, and improving the availability and service life of the battery system.

[0006] Preferably, the power MOSFET unit includes MOSFETs Q4, Q5, and Q6. MOSFETs Q4 and Q5 are connected in a sampling pair structure, with their two ends connected in series in a current loop. The controlled terminals of MOSFETs Q4 and Q5 are connected to form a controlled node. The first conducting terminal of MOSFET Q6 is grounded, and the second conducting terminal of MOSFET Q6 is connected to the controlled node. The controlled terminal of MOSFET Q6 is connected to the control signal output terminal of the control module.

[0007] By adopting the above technical solution, MOSFETs Q4 and Q5 are configured as a pair and driven by MOSFET Q6, the current loop can be simultaneously cut off in both forward and reverse directions in the off state. This avoids leakage paths caused by the conduction of the body diode, thereby achieving complete power-off and improving the reliability and safety of the protection.

[0008] Preferably, the power MOSFET unit further includes diodes D1 and D2. The control signal output terminal of the control module is connected to the anode of diode D1, and the cathode of diode D1 is connected to the controlled terminal of MOSFET Q6. The control signal output terminal of the primary protection module is connected to the anode of diode D2, and the cathode of diode D2 is connected to the controlled terminal of MOSFET Q6.

[0009] By adopting the above technical solution, the control signals of the primary protection module and the control module are combined by setting diodes D1 and D2, so that the two types of control signals can independently and simultaneously participate in the driving control of the power MOSFET unit, thereby forming a multi-source control path and improving the system's response capability and redundancy protection capability under different abnormal sources.

[0010] Preferably, the control module includes a control chip U2 and a step-down unit. The power input terminal of the control chip U2 is connected to the power output terminal of the step-down unit. The step-down unit includes a step-down chip U1, a capacitor C3, and a resistor R7. The power input terminal of the step-down chip U1 is connected to the power output terminal of the battery module. A capacitor C3 is connected between the power output terminal of the step-down chip U1 and ground. A resistor R7 is connected between the power output terminal of the step-down chip U1 and the power input terminal of the control chip U2.

[0011] By adopting the above technical solution, and by setting up a step-down unit to provide stable power to the control chip, the control module can maintain stable operation under battery voltage fluctuations, thereby ensuring the reliability of protection logic execution and avoiding misjudgment or protection failure caused by unstable power supply.

[0012] Preferably, the detection signal input terminal of the primary protection module includes a current sampling port and a voltage sampling port, and the status detection unit includes a current sampling unit and a voltage sampling unit. The current sampling unit includes an alloy resistor R49 and an alloy resistor R33 connected in series in the current loop. The two ends of the alloy resistor R49 are connected to the current sampling port, and the two ends of the alloy resistor R33 are connected to the detection signal input terminal of the control module. The sampling signal input terminal of the voltage sampling unit is connected to the voltage output terminal of the battery module, and the signal output terminal of the current sampling unit is connected to the voltage sampling port.

[0013] By adopting the above technical solution, and by simultaneously collecting current and voltage signals and transmitting them to the primary protection module and control module respectively, multi-parameter detection of battery status is achieved, making protection judgment more comprehensive and accurate, thereby improving the ability to identify abnormalities and reducing false triggering.

[0014] Preferably, the voltage sampling port includes a first differential numerator port and a second differential numerator port. The voltage sampling unit includes resistors R38, R24, R32, and R23, MOSFETs Q2 and Q3. Resistor R24 ​​is connected in parallel to one of the batteries in the battery module, and resistor R38 is connected in parallel to the other battery in the battery module. The common node between the first end of resistor R24 ​​and one of the batteries is connected to the first end of resistor R23. The second end of resistor R23 is connected to the first differential numerator port. The second end of resistor R24 ​​is connected to the first conducting end of MOSFET Q2. The second conducting end of MOSFET Q2 and the power output end of the other battery are combined into a conducting node. The conducting node is connected to the first end of resistor R38. The second end of resistor R38 is connected to the first conducting end of MOSFET Q3. The second conducting end of MOSFET Q3 is grounded. The controlled end of MOSFET Q3, the controlled end of MOSFET Q2, and the first end of resistor R32 are combined into a connection node. The connection node is connected to the second differential numerator port, and the second end of resistor R32 is connected to the conducting node.

[0015] By adopting the above technical solution and constructing a differential sampling structure that includes a resistor network and a MOSFET, the accurate extraction and conditioning of voltages at different battery nodes can be achieved. At the same time, the stability of the sampling signal is improved by utilizing a controlled conduction path, thereby enhancing the accuracy of voltage detection and its anti-interference capability.

[0016] Preferably, the primary protection module includes a battery management chip U3 and a switching element Q1. The switching element Q1 is connected in the current loop. The signal input terminal of the battery management chip U3 is connected to the first signal output terminal of the state detection module. The signal output terminal of the battery management chip U3 is connected to the controlled terminal of the switching element Q1. The switching element Q1 is a dual MOS packaged device.

[0017] By adopting the above technical solution, and by using the battery management chip and the switching conduction element to form a primary protection circuit, the current path can be quickly cut off at the hardware level when the battery malfunctions, thereby improving the response speed, reducing the system's dependence on the control module, and enhancing basic safety assurance capabilities.

[0018] A control method for a recoverable secondary protection circuit, applied to a recoverable secondary protection circuit, the control method comprising: The battery module is continuously monitored to obtain the corresponding battery state change trend. The battery state change trend includes at least the current change trend and the voltage change trend. The battery state change trend is integrated and processed by time series to generate the corresponding comprehensive state characterization parameters. Based on the comprehensive state characterization parameters, the battery module is matched with the preset graded threshold model to determine the current state level of the battery module. The state levels include normal state, first-level abnormal state and second-level abnormal state. When the status level is a Level 1 abnormal state, the switch conducting element located in the current loop in the Level 1 protection module is disconnected, and the tracking and judgment of the switch conducting element is initiated to generate the corresponding Level 1 protection status result. When the status level is a level 2 abnormal state, or the result of the level 1 protection status is a failure state, a corresponding level 2 protection trigger command is generated to perform bidirectional cut-off control on the current loop. After executing the secondary protection trigger command, the battery module is continuously monitored to obtain new comprehensive state characterization parameters. Based on the preset recovery judgment conditions, regression analysis is performed on the new comprehensive state characterization parameters to generate corresponding analysis results. Based on the analysis results, determine whether to generate a corresponding recovery control command to restore the conduction state of the current loop.

[0019] By adopting the above technical solution, the battery status is continuously monitored and combined with time series analysis and graded threshold model to distinguish and process different levels of abnormality. In the event of severe abnormality or failure of the first-level protection, the second-level protection is triggered. At the same time, the circuit is allowed to be reconnected after the status is restored, thus forming a complete closed-loop control mechanism of detection, judgment, disconnection and recovery.

[0020] Preferably, when the status level is a level two abnormal state, or the level one protection status result is a failure state, the step of generating the corresponding level two protection trigger instruction includes: Based on the comprehensive state characterization parameters, the corresponding abnormal duration features and change rate features are extracted, and the abnormal duration features and change rate features are subjected to correlation analysis to generate the corresponding failure judgment feature parameters. The failure determination feature parameters are matched with the preset failure determination model to generate the corresponding matching results, and the first-level protection status result is determined as a failure state based on the matching results. If so, the corresponding trigger weight is generated based on the matching result, and the corresponding secondary protection trigger instruction is generated based on the trigger weight.

[0021] By adopting the above technical solution, and by introducing the characteristics of abnormal duration and rate of change and performing correlation analysis, a failure judgment model is established, enabling the system to distinguish between transient abnormalities and real failures, thereby avoiding false triggering and increasing the trigger strength when failure is confirmed, thus achieving more accurate and reliable protection and control.

[0022] Preferably, the step of performing bidirectional cutoff control on the current loop includes: Based on the secondary protection trigger command, determine whether to execute the pre-shutdown process; If so, during the pre-shutdown process, the primary protection module takes over the control action of the secondary switch management module to determine whether to bidirectionally cut off the current loop. If not, the control module takes over the control actions of the secondary switch management module to determine whether to cut off the current loop in both directions.

[0023] By adopting the above technical solution, and by selecting different control paths according to the triggering conditions when performing bidirectional cutoff control, the system can flexibly switch control strategies under different abnormal scenarios, thereby improving the adaptability and response efficiency of protection actions and further enhancing the stability and reliability of the overall protection mechanism.

[0024] In summary, this application includes at least one of the following beneficial technical effects: This application continuously acquires battery status data such as voltage and current through a status detection module, and simultaneously provides the detection results to both the primary protection module and the control module, enabling the system to possess both rapid hardware response and logical decision-making capabilities. Furthermore, by incorporating a power MOSFET unit with a paired transistor structure as a secondary switch management module in the current loop, the conduction and disconnection of the current loop no longer rely on irreversible physical fuse breaking, but are actively controlled by the control module based on the detected status data. Building upon this, anomaly classification and failure identification logic is introduced. When a higher-level abnormal state is detected in the battery, or when the primary protection fails to effectively disconnect the loop, the control module directly controls the power MOSFET unit to perform bidirectional cutoff, thereby forming a controllable redundant disconnection path outside of the primary protection. The current loop disconnection behavior is transformed from the original passive one-time fuse breaking to a controllable, multiple-execution switching action. This not only enables rapid and reliable disconnection when an anomaly occurs, but also allows the loop to be reconnected after the battery status returns to a safe range, restoring the system to its operating state, thus significantly improving the availability of the battery system. Meanwhile, by employing a power MOSFET with a transistor-to-transistor structure to achieve bidirectional cutoff, current leakage caused by internal parasitic structures in the device during the off-state is avoided, resulting in a more thorough cutoff and improved protection reliability. Furthermore, through the synergistic action of the primary protection and the secondary switch management module, effective cutoff can still be achieved even if the primary protection fails or its response is insufficient, enhancing the system's fault tolerance in complex and abnormal scenarios. While ensuring battery safety, the protection mechanism achieves recoverability, controllability, and multi-level redundancy, improving the overall system stability and lifespan. Attached Figure Description

[0025] Figure 1 This is a flowchart of a recoverable secondary protection circuit according to an embodiment of this application; Figure 2 This is a partial circuit diagram of a recoverable secondary protection circuit according to one embodiment of this application; Figure 3 This is a partial circuit diagram of the control module in a recoverable secondary protection circuit according to one embodiment of this application; Figure 4 This is a flowchart of a control method for a recoverable secondary protection circuit according to an embodiment of this application. Detailed Implementation

[0026] The present application will be further described in detail below with reference to the accompanying drawings.

[0027] In one embodiment, such as Figure 1As shown, this application discloses a recoverable secondary protection circuit, including a battery module, a primary protection module, a status detection module, a control module, and a secondary switch management module; The primary protection module is connected in series in the current loop of the battery module and is used to perform primary disconnection of the current loop when the battery module is in the first preset abnormal state. The signal input terminal of the status detection module is used to detect the battery status data of the current loop. The first signal output terminal of the status detection module is connected to the detection signal input terminal of the first-level protection module, and the second signal output terminal of the status detection module is connected to the detection signal input terminal of the control module. The secondary switch management module includes a power MOSFET unit with a pair structure. The power MOSFET unit is connected in series in the current loop and is located on the loop path of the primary protection module in the current loop. The control signal output terminal of the control module is connected to the control signal input terminal of the secondary switch management module; When the control module determines whether the battery module is in a second preset abnormal state based on the battery status data, or detects that the first-level protection module is in a failed state, the control module controls the second-level switch management module to perform a second-level shutdown, so as to bidirectionally cut off the current loop through the power MOSFET unit. When the battery status data recovers to the preset safety range, the control module controls the secondary switch management module to turn on, so as to restore the current loop of the battery module.

[0028] In this embodiment, the battery module constitutes the energy supply source for the entire current loop. Its positive and negative output terminals serve as the start and return terminals of the current loop, respectively, and all protection structures are sequentially arranged around this current loop. A primary protection module is connected in series in the current output path of the battery module. Its input terminal is directly electrically connected to the output terminal of the battery module, and its output terminal continues to connect to the subsequent current loop, used to preferentially disconnect this path when a primary anomaly is detected. The detection signal input terminal of this primary protection module does not acquire information independently, but rather receives data support from the status detection module, thereby achieving real-time sensing of the battery's operating status.

[0029] The status detection module is positioned at key nodes in the current loop and battery module. Its signal input terminals are connected to the voltage output node of the battery module and the sampling node in the current loop, respectively, to extract voltage and current information characterizing the battery's operating status. This status detection module further has two signal output paths. One path outputs to the detection signal input terminal of the primary protection module, enabling the primary protection module to respond quickly based on the sampled data. The other path outputs to the detection signal input terminal of the control module, allowing the control module to perform higher-level logical judgments based on the same set of status data. This dual-path data distribution structure achieves synergy between hardware-level rapid protection and control-level decision analysis.

[0030] The control module is located on the control side of the current loop. Its detection signal input terminal is connected to the second signal output terminal of the status detection module to receive battery status data and perform comprehensive analysis and processing. The control signal output terminal of the control module is electrically connected to the control signal input terminal of the secondary switch management module to send conduction or shutdown commands to the secondary switch management module, thereby realizing active control of the current loop. During operation, the control module not only determines abnormal battery status but also identifies the status of the response results of the primary protection module. When it determines that the primary protection has failed to effectively disconnect the circuit, it can further trigger the secondary protection action.

[0031] The secondary switch management module is also connected in series in the current loop and arranged on the loop path of the primary protection module, forming a series relationship with the primary protection module in the current loop. This module internally houses a power MOSFET unit with a paired-transistor structure. Its two ends are connected to the upstream and downstream nodes of the current loop, allowing current to flow normally in the on-state and completely cutting off the current loop in the off-state. The controlled terminal of the power MOSFET unit is connected to the control signal output terminal of the control module, changing its on-state upon receiving a control signal. Due to the paired-transistor structure, the power MOSFET unit can simultaneously block both forward and reverse current paths when turned off, thus avoiding leakage caused by internal parasitic structures.

[0032] During actual operation, when the battery module is in a normal state, both the primary protection module and the secondary switch management module remain on, and the current loop is connected. When the battery condition reaches the first preset abnormal state, the primary protection module cuts off the current loop based on the data provided by the state detection module, achieving primary protection. If the battery condition further deteriorates to the second preset abnormal state, or if the control module determines through analysis of the state detection data that the primary protection module has failed to effectively cut off the current, the control module outputs a control signal to turn off the power MOSFET unit in the secondary switch management module, thereby bidirectionally cutting off the current loop. Since this cutting-off process is actively controlled by the control module, after the battery condition recovers to the preset safe range, the control module can output a conduction signal again to restore the power MOSFET unit to the conducting state, thereby re-establishing the current loop and realizing the system's recovery operation.

[0033] Furthermore, such as Figure 2 As shown, the power MOSFET unit includes MOSFETs Q4, Q5, and Q6. MOSFETs Q4 and Q5 are connected in a sampling pair structure, with their two ends connected in series in a current loop. The controlled terminals of MOSFETs Q4 and Q5 are connected to form a controlled node. The first conducting terminal of MOSFET Q6 is grounded, and the second conducting terminal of MOSFET Q6 is connected to the controlled node. The controlled terminal of MOSFET Q6 is connected to the control signal output terminal of the control module.

[0034] Furthermore, such as Figure 2 As shown, the power MOSFET unit also includes diodes D1 and D2. The control signal output terminal of the control module is connected to the anode of diode D1, and the cathode of diode D1 is connected to the controlled terminal of MOSFET Q6. The control signal output terminal of the primary protection module is connected to the anode of diode D2, and the cathode of diode D2 is connected to the controlled terminal of MOSFET Q6.

[0035] In this embodiment, the power MOSFET unit is not isolated, but forms a current loop control structure with multi-source control capability together with the control module and the primary protection module. Specifically, MOSFETs Q4 and Q5 are connected in a paired manner, and both are power MOSFET devices of the same type, such as... Figure 2 The LT4205FNKQ in the example has internal channels arranged in opposite directions, forming a mating structure through its source side. This creates a low-resistance conduction path when the transistor is on, and simultaneously cuts off the current loop in both the forward and reverse directions when it is off. This pair of transistors is connected in series on the P+ side of the battery output path, directly undertaking the main switching function of the current loop.

[0036] In terms of control relationship, the controlled terminals of MOSFETs Q4 and Q5 are electrically connected to form a unified controlled node. This controlled node is not directly driven by the control module, but is indirectly controlled through MOSFET Q6. Specifically, MOSFET Q6 is a small-signal NMOS device, such as AT2N7002K-C. Its second conducting terminal is connected to the controlled node, and its first conducting terminal is grounded. Thus, when MOSFET Q6 is turned on, it quickly pulls down the potential of the controlled node, enabling MOSFETs Q4 and Q5 to obtain an effective gate-source voltage difference and enter the conducting state. When MOSFET Q6 is turned off, the controlled node is pulled up by the external resistor network (such as resistors R2 and R5), reducing the gate-source voltage difference of MOSFETs Q4 and Q5 to the off state, thereby cutting off the main current path.

[0037] Furthermore, to implement multi-source control logic, the controlled terminal of MOSFET Q6 is not a single signal input, but is connected to the control module output signal EN and the primary protection module output signal EN-BMS respectively through diodes D1 and D2. Specifically, the anodes of diodes D1 and D2 are connected to the corresponding control signal sources, and their cathodes are combined and connected to the controlled terminal of MOSFET Q6, thus forming a hardware-level or logic structure. When the control module outputs the control signal EN, MOSFET Q6 can be driven through D1; when the primary protection module output signal EN-BMS changes, the same node can be controlled through D2. This structure allows any control source to affect the conduction state of MOSFET Q6, thereby indirectly controlling the conduction or cutoff of MOSFETs Q4 and Q5.

[0038] In practical operation, when the system is in a normal state, the control module outputs a control signal to turn on MOSFET Q6, thus turning on MOSFETs Q4 and Q5 and connecting the current loop. When an abnormal state is detected, the control module can cancel the drive signal, turning off MOSFET Q6, thereby turning off MOSFETs Q4 and Q5 and cutting off the current loop. Simultaneously, when the primary protection module detects an abnormality and outputs a control signal, even if the control module does not act, this signal can directly act on the controlled terminal of MOSFET Q6 through D2, thereby changing the state of MOSFET Q6 and controlling MOSFETs Q4 and Q5, forming a redundant control path for the control module.

[0039] In addition, in this control link, resistor R6 can be used to pull down the controlled terminal of MOSFET Q6 to stabilize it, so as to avoid false triggering caused by floating control signal. At the same time, resistors R2 and R5 are used to bias the gate of the power MOSFET to reliably turn it off in the undriven state, thereby improving the stability and anti-interference capability of the entire switching control process.

[0040] Furthermore, such as Figures 2-3 As shown, the control module includes a control chip U2 and a step-down unit. The power input terminal of the control chip U2 is connected to the power output terminal of the step-down unit. The step-down unit includes a step-down chip U1, a capacitor C3, and a resistor R7. The power input terminal of the step-down chip U1 is connected to the power output terminal of the battery module. A capacitor C3 is connected between the power output terminal of the step-down chip U1 and ground. A resistor R7 is connected between the power output terminal of the step-down chip U1 and the power input terminal of the control chip U2.

[0041] In this embodiment, the control module includes a control chip U2 and a step-down unit that provides stable power to it. The control chip U2 serves as the core of the secondary protection logic; its detection signal input receives battery status data from the status detection module, and its control signal output outputs control signals to the secondary switch management module, thereby controlling the on / off state of the current loop. To ensure stable operation of the control chip U2 under different battery conditions, the step-down unit converts the power supply voltage output by the battery module into a stable operating voltage suitable for the control chip U2.

[0042] Specifically, the step-down unit includes a step-down chip U1, a capacitor C3, and a resistor R7. The step-down chip U1 is a linear regulator, and its power input terminal is connected to the power output terminal of the battery module to receive the input voltage from the battery module. The power output terminal of the step-down chip U1 outputs a regulated power supply signal of a preset voltage level. This regulated power supply signal is transmitted to the power input terminal of the control chip U2 after passing through the resistor R7 to provide a stable operating power supply for the control chip U2.

[0043] Capacitor C3 is connected between the power output terminal of the step-down chip U1 and ground. It is used to filter the regulated power supply signal. When the output voltage of the step-down chip U1 experiences transient fluctuations, it suppresses voltage ripple through the charging and discharging process, thereby improving the stability of the output voltage and preventing the control chip U2 from malfunctioning or operating abnormally due to power supply fluctuations.

[0044] Resistor R7 is connected in series between the power output terminal of step-down chip U1 and the power input terminal of control chip U2 to regulate the power supply path. On the one hand, it limits the impact of sudden current changes on control chip U2, and on the other hand, it forms a damping network with the parasitic capacitance at the input terminal of control chip U2 to suppress the coupling of high-frequency interference signals into the control chip, thereby improving the anti-interference capability of the control module.

[0045] In terms of control logic, the battery module first provides input power to the buck converter U1. The buck converter U1 converts the input voltage into a stable target voltage and supplies power to the control chip U2 through resistor R7, enabling the control chip U2 to obtain a stable operating power supply. Based on this, the control chip U2 analyzes the operating status of the battery module in conjunction with the detection signal from the status detection module. When it is determined that the battery module is in a second preset abnormal state or the first-level protection module is in a failed state, the control chip U2 outputs a control signal through its control signal output terminal to control the power MOSFET unit in the second-level switch management module to perform a turn-off operation. When the battery status recovers to the preset safe range, the control chip U2 outputs a turn-on signal to turn on the power MOSFET unit again, thereby re-establishing the current loop.

[0046] Furthermore, in engineering implementation, the step-down chip U1 and capacitor C3 can together form a regulated output subunit to achieve a stable conversion from battery-side voltage to control-side voltage. The power supply path formed by resistor R7 and the input terminal of control chip U2 can be summarized as a power supply conditioning subunit to enhance the stability and anti-interference capability of the control module's power supply. Through the connection and synergistic effect between these components, the control module remains in a stable operating state throughout the entire battery protection process, thus providing a reliable foundation for the accurate execution of the secondary protection logic.

[0047] Furthermore, such as Figure 2 As shown, the detection signal input terminal of the primary protection module includes a current sampling port and a voltage sampling port. The status detection unit includes a current sampling unit and a voltage sampling unit. The current sampling unit includes an alloy resistor R49 and an alloy resistor R33 connected in series in the current loop. The two ends of the alloy resistor R49 are connected to the current sampling port, and the two ends of the alloy resistor R33 are connected to the detection signal input terminal of the control module. The sampling signal input terminal of the voltage sampling unit is connected to the voltage output terminal of the battery module, and the signal output terminal of the current sampling unit is connected to the voltage sampling port.

[0048] In this embodiment, the detection signal input terminal of the primary protection module is composed of a current sampling port and a voltage sampling port, which are used to acquire current information and voltage information that characterize the operating state of the battery module, respectively. Correspondingly, the state detection module is specifically composed of a current sampling unit and a voltage sampling unit, and achieves real-time extraction and transmission of battery state data by establishing electrical connections with the battery module and key nodes in the current loop.

[0049] Specifically, the current sampling unit includes a first alloy resistor R49 and a second alloy resistor R33 connected in series in the current loop. The two ends of the first alloy resistor R49 are connected to the current sampling port to provide a current detection signal to the primary protection module. The second alloy resistor R33 is also connected in series in the current loop, with its two ends connected to the detection signal input terminal of the control module to provide current sampling data to the control module. Since the first alloy resistor R49 and the second alloy resistor R33 are located on the same current path, voltage drops are generated at both ends when the current flows through this path. This allows for separate path transmission of the same current signal to the primary protection module and the control module, enabling independent judgment by the primary protection and secondary control modules based on the same physical current.

[0050] In terms of specific connections, the input node of the current sampling port is directly taken from both ends of the first alloy resistor R49. This differential voltage reflects the current magnitude in the current loop and is transmitted to the battery management chip U3 in the primary protection module, enabling it to quickly identify abnormal states such as overcurrent. Simultaneously, both ends of the second alloy resistor R33 are connected to the detection signal input terminal of the control chip U2 via wires, allowing the control chip U2 to acquire current change information and participate in higher-level state analysis and anomaly determination. This structure ensures that the current detection signal meets both the rapid response requirements of the primary protection and the control module's need to analyze current change trends.

[0051] Furthermore, to improve the stability and anti-interference capability of the current sampling signal, a resistor network and filter elements for signal conditioning can be set across the second alloy resistor R33. For example, resistors R11 and R12 and capacitor C6 can be set. Resistors R11 and R12 are connected in series in the sampling signal path to limit and dampen the sampling signal. Capacitor C6 is connected between the sampling signal node and ground to filter high-frequency noise, thereby making the current signal transmitted to the control chip U2 smoother and more stable, and avoiding misjudgment due to transient interference.

[0052] The sampling signal input terminal of the voltage sampling unit is connected to the voltage output node of the battery module to obtain the terminal voltage information of the battery module. In the actual circuit, this voltage sampling unit can be implemented through multi-point voltage sampling, that is, multiple voltage detection pins (such as VC1 to VC4) of the battery management chip U3 are connected to the voltage nodes of each cell in the battery module, thereby realizing point-by-point monitoring of the voltage of multiple battery cells. At the same time, filter components such as capacitors C11 and C12 can be set at each voltage sampling node to filter the sampled voltage and improve the stability of the voltage detection signal.

[0053] In terms of signal output, a connection is established between the signal output terminal of the current sampling unit and the voltage sampling port, enabling the current sampling signal to be uniformly summarized or further transmitted at the voltage sampling port, thereby providing comprehensive battery status information to the primary protection module. Simultaneously, the voltage sampling unit and the current sampling unit cooperate structurally, allowing the status detection module to simultaneously output both current and voltage parameters. This supports rapid hardware determination by the primary protection module and more complex logic analysis by the control module.

[0054] In terms of overall control logic, when the battery module is in normal operating condition, the current sampling unit and voltage sampling unit continuously output stable detection signals. The primary protection module and control module maintain the current loop conduction based on their respective acquired detection data. When the current or voltage reaches a preset abnormal threshold, the primary protection module can prioritize the execution of protection actions based on the data provided by the current sampling port or voltage sampling port. Simultaneously, the control module analyzes the detection data from the second alloy resistor R33 and the voltage sampling node to further determine the degree of abnormality and trigger secondary protection when necessary. Through this structure, current and voltage detection possess both independence and synergy, thereby improving the detection accuracy and response reliability of the overall protection system.

[0055] Furthermore, such as Figure 2 As shown, the voltage sampling port includes a first differential numerator port and a second differential numerator port. The voltage sampling unit includes resistors R38, R24, R32, R23, MOSFET Q2, and MOSFET Q3. Resistor R24 ​​is connected in parallel to one of the batteries in the battery module, and resistor R38 is connected in parallel to the other battery in the battery module. The common node between the first end of resistor R24 ​​and one of the batteries is connected to the first end of resistor R23. The second end of resistor R23 is connected to the first differential numerator port. The second end of resistor R24 ​​is connected to the first conducting end of MOSFET Q2. The second conducting end of MOSFET Q2 and the power output end of the other battery are combined into a conducting node. The conducting node is connected to the first end of resistor R38. The second end of resistor R38 is connected to the first conducting end of MOSFET Q3. The second conducting end of MOSFET Q3 is grounded. The controlled end of MOSFET Q3, the controlled end of MOSFET Q2, and the first end of resistor R32 are combined into a connection node. The connection node is connected to the second differential numerator port, and the second end of resistor R32 is connected to the conducting node.

[0056] In this embodiment, the voltage sampling port includes a first differential numerator port and a second differential numerator port. These are not isolated but, together with the voltage sampling unit, form a differential voltage detection link facing the primary protection module. This link converts the potential difference between different cell nodes in the battery module into a detection signal that can be recognized by the primary protection module. (Circuit connection)Figure 2 It can be seen that the voltage sampling unit is mainly composed of resistors R38, R24, R32, R23, MOSFET Q2, and MOSFET Q3. The first differential port corresponds to the sampling node connected to the voltage detection pin of the battery management chip U3 in the circuit. The second differential port corresponds to the connection node formed by MOSFET Q2, MOSFET Q3, and resistor R32, and is finally connected to another detection path of the battery management chip U3, thus forming a differential detection relationship.

[0057] Specifically, resistor R24 ​​is connected in parallel across one of the cells in the battery module to extract and current-limit the node voltage of that cell. The first terminal of resistor R24 ​​forms a common node with one of the cells, which is also connected to the first terminal of resistor R23. Resistor R23 is connected in series between this common node and the first differential port. This serves two purposes: firstly, it transmits the potential of the corresponding cell node to the first differential port; secondly, it limits transient current in the sampling branch, reducing the risk of impact on the subsequent detection pins. In other words, resistors R24 and R23 together constitute the first voltage extraction branch. Their function is not merely simple conduction, but rather, to stably send the potential information of the target cell node to the first differential port without significantly affecting the battery's operating state.

[0058] MOSFET Q2 is positioned between the second terminal of resistor R24 ​​and the output node of another battery cell. Its first conducting terminal is connected to the second terminal of resistor R24, and its second conducting terminal is combined with the power output terminal of the other battery cell to form a conducting node. This conducting node is also connected to the first terminal of resistor R38. Therefore, MOSFET Q2 is structurally located between the upper sampling branch and the intermediate conducting node. Its function can be understood as selectively controlling the conduction state of the upper sampling branch, enabling the sampling potential corresponding to the first battery cell to establish an electrical connection with the intermediate conducting node when the control conditions are met, thus participating in the subsequent differential voltage construction. Correspondingly, resistor R38 is connected in parallel across the other battery cell in the battery module to extract the node voltage of the other battery cell. Its first terminal is connected to the conducting node, and its second terminal is connected to the first conducting terminal of MOSFET Q3. The second conducting terminal of MOSFET Q3 is grounded. Therefore, resistor R38 and MOSFET Q3 together constitute another controlled sampling branch extending from the intermediate conducting node to the ground side. When the MOSFET Q3 meets the conduction condition, this branch establishes a potential transmission path, enabling the sampling voltage corresponding to the other battery to form a ground reference relationship through resistor R38, thus forming a differential detection basis together with the first sampling branch.

[0059] In terms of control relationships, the controlled terminals of MOSFET Q2 and Q3, along with the first terminal of resistor R32, form a connection node, which is connected to the second differential numerator port. Therefore, in this embodiment, the second differential numerator port not only serves as the output of the second differential sampling signal but also acts as a common control node for MOSFETs Q2 and Q3. In other words, the second differential numerator port is not simply a measurement terminal but possesses the dual attributes of a sampling node and a control node. When the potential of this connection node changes, the gate-source voltage difference between MOSFETs Q2 and Q3 changes synchronously, causing a corresponding change in their conduction states, thereby determining whether the upper and lower sampling branches establish a conduction path. The second terminal of resistor R32 is connected to the conduction node; therefore, resistor R32 actually constitutes a resistive coupling branch between the connection node and the conduction node. Its function is to provide the potential transfer relationship between the connection node and the conduction node and to provide necessary damping and bias conditioning when the control node potential changes, thereby avoiding oscillation or false triggering problems caused by a direct rigid connection of the MOSFET control terminals.

[0060] From an engineering perspective, MOSFETs Q2 and Q3 are not used for main power switching, but rather as switching conditioning elements in the sampling path. They are used to establish or release the electrical relationship between sampling nodes under different states, enabling the primary protection module to obtain voltage differential information between target cells under controlled conditions. The first differential numerator port primarily handles the extraction of the detected potential, while the second differential numerator port handles the construction of the reference potential and the switching control node. Together, they allow the battery management chip U3 to identify the voltage signal provided by the voltage sampling unit, thereby determining whether the corresponding cell is in an abnormal operating range. Especially in multi-cell series scenarios, this differential sampling structure avoids the common-mode drift problem caused by single-ended ground sampling, making voltage detection more suitable for node measurement of series-connected batteries.

[0061] Capacitor C13 is connected near the upper sampling node, and capacitor C19 is connected near the lower sampling node. Both can serve as filtering elements in the sampling branch to absorb high-frequency noise and spike interference, reducing the impact of sampling node voltage fluctuations on the detection accuracy of the battery management chip U3. Through this filtering structure, the differential signals output from the first and second differential ports are more stable, helping the primary protection module to make reliable judgments when overcharging, over-discharging, or abnormal node voltages occur.

[0062] Furthermore, such as Figure 2As shown, the primary protection module includes a battery management chip U3 and a switching element Q1. The switching element Q1 is connected in the current loop. The signal input terminal of the battery management chip U3 is connected to the first signal output terminal of the status detection module. The signal output terminal of the battery management chip U3 is connected to the controlled terminal of the switching element Q1. The switching element Q1 is a dual MOS packaged device.

[0063] In this embodiment, the primary protection module consists of a battery management chip U3 and a switching element Q1. The battery management chip U3 serves as the core control unit for primary protection, with its signal input terminals connected to the current sampling unit and voltage sampling unit in the status detection module, respectively, to receive detection data characterizing the battery module's operating status. The switching element Q1 is connected in series in the current loop and acts as the primary protection actuator, switching on or off the current loop upon receiving a control signal from the battery management chip U3. (Circuit connection details omitted) Figure 2 It can be seen that the battery management chip U3 corresponds to the model CBM8580. Its SRP and SRN pins are respectively connected to the two ends of the second alloy resistor R33 in the current sampling unit to detect current changes; its VC1 to VC4 pins are respectively connected to the voltage sampling nodes of each battery in the battery module to detect the voltage status of each battery.

[0064] Specifically, the battery management chip U3 obtains the voltage difference signal generated by the second alloy resistor R33 through its SRP and SRN pins, thereby determining the current magnitude in the current loop. Combined with the battery node voltage information obtained from its VC1 to VC4 pins, it determines whether the battery module is in an abnormal state such as overcurrent, overcharge, or over-discharge. When an abnormal state is detected, the battery management chip U3 outputs a control signal through its control output pins, such as DSG, CHG, or the corresponding EN-BMS control signal terminal. This control signal directly acts on the controlled terminal of the switching element Q1, causing a change in the conduction state of the switching element Q1. Furthermore, it can participate in the control of the subsequent secondary switch management module through an external connection path, such as the EN-BMS node, thus forming a multi-level protection linkage mechanism.

[0065] The switching element Q1 is a dual-MOS packaged device, containing two MOSFETs arranged back-to-back in a transistor pair structure and connected in series in the current loop. Under normal operating conditions, the battery management chip U3 outputs a control signal to maintain conduction, keeping the switching element Q1 in the ON state and the current loop connected. When the battery management chip U3 detects an abnormal state, its control output signal changes, altering the potential of the controlled terminal of the switching element Q1, thereby turning off the internal MOSFETs and rapidly cutting off the current loop. Because the switching element Q1 uses a dual-MOS transistor pair structure, it can simultaneously block both forward and reverse current paths in the OFF state, thus avoiding the unidirectional conduction problem caused by the MOSFET body diode and improving the reliability of the first-level protection.

[0066] In terms of specific connections, the control output terminal of the battery management chip U3 is directly connected to the controlled terminal of the switching element Q1 via a wire. Simultaneously, this control signal is also led out through a signal node identified as EN-BMS, and merges with the control signal output from the control module via devices such as diode D2, thus jointly acting on the driving devices in the secondary switch management module, such as MOSFET Q6. Therefore, the battery management chip U3 not only undertakes the primary protection judgment and execution functions, but also provides status indications or control participation to the subsequent protection structure through its output signal, establishing a signal coupling relationship between the primary and secondary protection.

[0067] In addition, decoupling capacitors C11 and C12 are installed between the power input terminal and ground of the battery management chip U3 to stabilize its power supply voltage and prevent detection errors or control anomalies caused by power fluctuations. A temperature sensor NTC1 is connected to its temperature detection pin to acquire battery temperature information, enabling the battery management chip U3 to further combine temperature parameters for protection decisions, thereby expanding the detection dimensions of the first-level protection. Although these auxiliary components do not directly participate in the switching control, they have a significant impact on the detection accuracy and operational stability of the battery management chip U3.

[0068] In terms of overall control logic, when the battery module is in a normal state, the battery management chip U3 maintains the switching element Q1 on based on detected current, voltage, and temperature data, ensuring normal operation of the current loop. When an abnormal state is detected, the battery management chip U3 immediately changes its output control signal, causing the switching element Q1 to turn off, thus achieving primary protection disconnection. Simultaneously, this abnormal state signal is transmitted to the next stage via the EN-BMS path, enabling the secondary switch management module to sense the primary protection status and participate in control when the primary protection fails or the abnormality worsens. Through this structure and control relationship, the primary protection module not only possesses rapid response capabilities but also can form a linkage with the subsequent secondary protection, improving the overall system's protection reliability under complex operating conditions.

[0069] like Figure 4 As shown, a control method for a recoverable secondary protection circuit is applied to a recoverable secondary protection circuit. The control method includes: S10. Continuously monitor the battery module to obtain the corresponding battery state change trend. The battery state change trend includes at least the current change trend and the voltage change trend. Perform time series integration processing on the battery state change trend to generate the corresponding comprehensive state characterization parameters. S20. Based on the comprehensive state characterization parameters, match them with the preset graded threshold model to determine the current state level of the battery module. The state level includes normal state, first-level abnormal state and second-level abnormal state. S30. When the status level is a first-level abnormal state, disconnect the switch conducting element located in the current loop in the first-level protection module, and start the tracking and judgment of the switch conducting element to generate the corresponding first-level protection status result. S40. When the status level is a level 2 abnormal state, or the status result of the level 1 protection is a failure state, generate the corresponding level 2 protection trigger command to perform bidirectional cut-off control on the current loop. S50. After executing the secondary protection trigger command, continue to monitor the battery module to obtain new comprehensive state characterization parameters. Based on the preset recovery judgment conditions, perform regression analysis on the new comprehensive state characterization parameters to generate corresponding analysis results. S60. Based on the analysis results, determine whether to generate a corresponding recovery control command to restore the conduction state of the current loop.

[0070] In this embodiment, a battery module refers to a power supply unit composed of one or more battery cells, whose output terminal forms a current loop power input terminal. In practical applications, it can be a series or parallel lithium battery pack. Its voltage and current states change in real time with load variations and the charging and discharging process, making it the object monitored and protected in the entire control method. Continuous monitoring refers to periodically or in real time sampling the key electrical parameters of the battery module through the sampling circuit in the state detection module. This sampling process can be achieved through a current sampling resistor and a voltage sampling network, and the control chip continuously acquires data according to a fixed sampling period, thereby forming a continuous state data stream.

[0071] Battery state change trends refer to the patterns of change in current and voltage data over multiple sampling periods, not instantaneous values ​​at a single moment. They reflect the direction and amplitude of these changes over time. Current change trends reflect increases, decreases, or abrupt changes in current, while voltage change trends reflect fluctuations, decay, or abnormal increases in battery voltage. Time series integration processing involves arranging battery state data acquired over multiple consecutive sampling periods in chronological order and processing it using methods such as filtering, weighting, or sliding windows to eliminate transient interference and extract stable features. The comprehensive state characterization parameters generated after this processing provide a comprehensive description of the battery state, which may include average current value, voltage change slope, and current fluctuation amplitude, used for subsequent state determination.

[0072] The preset grading threshold model is a pre-defined judgment model used to classify the battery's operating state levels. This model can consist of multiple threshold intervals or combinations of multiple parameters, such as dividing current, voltage, and their rate of change into different intervals, and forming the basis for state judgment through logical combinations. The state level is the classification result obtained by matching the comprehensive state characterization parameters with this model. The normal state indicates that the battery is operating within a safe range, the first-level abnormal state indicates that there is a slight abnormality but has not yet reached a dangerous level, and the second-level abnormal state indicates that it has reached a dangerous state that requires immediate protection.

[0073] The primary protection module refers to the basic protection circuit installed in the current loop. It internally includes a switching element for performing the interruption action and a detection circuit for detecting the battery status. When an abnormality is detected, it can directly cut off the current loop. The switching element is typically a power MOSFET or a combination thereof, allowing current to flow in the on state and blocking the current path in the off state. Tracking judgment refers to the control module continuing to monitor the battery status and current loop status after the primary protection action. By comparing the current and voltage changes before and after the protection action, it determines whether the switching element successfully cut off the current loop, thus generating a primary protection status result. The primary protection status result characterizes the effectiveness of the primary protection module's execution and can include an effective state or a failed state. When the current does not decrease as expected or the voltage does not change accordingly, it can be determined as a failed state.

[0074] The secondary protection trigger command is a control signal generated by the control module when it detects a higher-level anomaly or a failure of the primary protection. This command drives the secondary switch management module to perform a shutdown action. Bidirectional cutoff control refers to cutting off the current loop by using a power MOSFET with a transistor structure, preventing current from flowing in both the forward and reverse paths, thus achieving a complete disconnection of the current loop. The current loop refers to the current transmission path formed by the battery module, load, and various protection modules connected in series; it is the channel for electrical energy transmission.

[0075] The preset recovery judgment conditions are a set of conditions used to determine whether the battery state has recovered to a safe range. These conditions can be determined based on factors such as voltage recovery to the normal range, current decrease to a safe range, and a stabilizing trend. Regression analysis refers to trend analysis of new comprehensive state characterization parameters. By comparing the changes in historical data with current data, it determines whether the system has gradually returned to a normal state from an abnormal state. The analysis result is the judgment output after regression analysis, used to indicate whether the current state meets the recovery conditions. The recovery control command is a control signal generated by the control module after confirming that the battery state has recovered. It is used to drive the secondary switch management module to re-circuit the current loop, enabling the system to return to normal operating status.

[0076] Furthermore, when the status level is a level two abnormal state, or the level one protection status result is a failure state, the step of generating the corresponding level two protection trigger instruction includes: S4011. Based on the comprehensive state characterization parameters, extract the corresponding abnormal duration features and change rate features, and perform correlation analysis on the abnormal duration features and change rate features to generate the corresponding failure judgment feature parameters. S4012. Match the failure determination feature parameters with the preset failure determination model to generate the corresponding matching results, and determine whether the first-level protection status result is a failure status based on the matching results. S4013. If so, generate the corresponding trigger weight based on the matching result, and generate the corresponding secondary protection trigger instruction based on the trigger weight.

[0077] Furthermore, the steps for bidirectional cutoff control of the current loop include: S4021. Based on the secondary protection trigger instruction, determine whether to execute the pre-shutdown process; S4022. If so, during the pre-shutdown process, the primary protection module takes over the control action of the secondary switch management module to determine whether to bidirectionally cut off the current loop. S4023. If not, the control module takes over the control action of the secondary switch management module to determine whether to cut off the current loop in both directions.

[0078] In this embodiment, the comprehensive state characterization parameter is multi-dimensional feature data obtained through time series integration processing after continuous sampling of the battery module. It includes not only instantaneous voltage and current information but also dynamic features obtained through filtering, averaging, and trend extraction, comprehensively reflecting the current operating state of the battery. The abnormal duration feature extracted based on this comprehensive state characterization parameter refers to the length of time the battery state deviates from the normal range and remains in an abnormal state. This duration is typically calculated by the time span of the abnormal interval in the continuously sampled data, used to distinguish between transient interference and persistent abnormalities. The rate of change feature characterizes the slope or gradient of current or voltage changes over time, calculated by the difference between adjacent sampling points, reflecting the severity of the abnormal change. By performing correlation analysis on the abnormal duration feature and the rate of change feature, a feature quantity comprehensively reflecting abnormal behavior can be constructed. This feature quantity is the failure judgment feature parameter, essentially a judgment criterion fused with the time dimension and the change intensity dimension.

[0079] The preset failure judgment model is a set of judgment rules established based on empirical or experimental data. It can be implemented using threshold ranges, rule-based judgments, or function models, and is used to match and judge failure judgment feature parameters. After the failure judgment feature parameters are matched with this model, a corresponding matching result is output. This matching result indicates whether the current anomaly belongs to a failure situation that the primary protection cannot effectively handle. The primary protection status result determined based on this matching result further confirms the execution effect of the primary protection module. When the matching result meets the failure judgment conditions, it indicates that although the primary protection module has acted, it has not formed an effective disconnection, and a higher level of protection processing is required.

[0080] Based on this, the trigger weight generated according to the matching results is a control parameter used to quantify the severity of the anomaly. Its value can be calculated based on the anomaly duration, rate of change, and degree of matching, reflecting the current risk level of the anomaly. This trigger weight further participates in the generation process of the secondary protection trigger command. When the trigger weight reaches a preset threshold, the control module generates the corresponding secondary protection trigger command and determines its execution strength or execution priority. The secondary protection trigger command is essentially a control signal used to control the conduction state of the power MOSFET unit in the secondary switch management module, which is used to drive the current loop into the cut-off state.

[0081] In the execution of bidirectional cutoff control, the pre-shutdown process refers to a transitional control process before directly executing complete shutdown. Its purpose is to avoid voltage surges or current spikes caused by sudden disconnection. This process can be achieved by gradually controlling the gate voltage of the power MOSFET or through an intermediate state control path, gradually reducing the current. Based on the secondary protection trigger command, the control module first determines whether the pre-shutdown process needs to be executed. This determination can be based on trigger weight or exception type. When it is determined that execution is necessary, the pre-shutdown process is entered. At this time, the primary protection module takes over the control action of the secondary switch management module. This means using the existing control output path of the primary protection module to control the power MOSFET unit, making it participate in the shutdown process, thus forming a cooperative control method that reduces control surges while ensuring safety. When it is determined that the pre-shutdown process does not need to be executed, the control module directly takes over the control action of the secondary switch management module. The control signal output by the control module directly drives the power MOSFET unit to complete shutdown, thereby achieving rapid disconnection of the current loop.

[0082] For example, in practical applications, when a battery module experiences a rapid rise in current for a short period, the failure judgment characteristic parameters obtained through the calculation of the rate of change characteristics and the abnormal duration characteristics may not reach the threshold of the failure judgment model. In this case, the matching result indicates that the primary protection may still be effective, and the system will not immediately enter the secondary protection. However, when the abnormal duration is prolonged and the current remains above the safe range, the failure judgment characteristic parameters are matched with the preset model, and the system determines that the primary protection has failed. Based on the matching result, the system generates a higher trigger weight and outputs a secondary protection trigger command. When executing this command, if the detected current change is relatively gradual, the system first enters the pre-shutdown processing flow, gradually reducing the current through the control path of the primary protection module; if the abnormal change is drastic, the control module directly drives the power MOSFET unit to quickly turn off, achieving bidirectional cutoff of the current loop, thereby completing the protection action.

[0083] The above-described embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application, and should all be included within the protection scope of this application.

Claims

1. A recoverable secondary protection circuit, characterized in that, It includes a battery module, a primary protection module, a status detection module, a control module, and a secondary switch management module; The primary protection module is connected in series in the current loop of the battery module and is used to perform primary disconnection of the current loop when the battery module is in a first preset abnormal state. The signal input terminal of the status detection module is used to detect the battery status data of the current loop. The first signal output terminal of the status detection module is connected to the detection signal input terminal of the primary protection module, and the second signal output terminal of the status detection module is connected to the detection signal input terminal of the control module. The secondary switch management module includes a power MOSFET unit with a pair structure. The power MOSFET unit is connected in series in the current loop and is located on the loop path of the primary protection module in the current loop. The control signal output terminal of the control module is connected to the control signal input terminal of the secondary switch management module; When the control module determines whether the battery module is in a second preset abnormal state based on the battery status data, or detects that the first-level protection module is in a failed state, the control module controls the second-level switch management module to perform a second-level shutdown, so as to bidirectionally cut off the current loop through the power MOS transistor unit. When the battery status data recovers to a preset safety range, the control module controls the secondary switch management module to turn on, so as to restore the current loop of the battery module.

2. The recoverable secondary protection circuit according to claim 1, characterized in that, The power MOSFET unit includes MOSFETs Q4, Q5, and Q6. MOSFETs Q4 and Q5 are connected in a sampling pair structure, with both ends of the pair structure connected in series in the current loop. The controlled terminals of MOSFETs Q4 and Q5 are connected to form a controlled node. The first conducting terminal of MOSFET Q6 is grounded, and the second conducting terminal of MOSFET Q6 is connected to the controlled node. The controlled terminal of MOSFET Q6 is connected to the control signal output terminal of the control module.

3. The recoverable secondary protection circuit according to claim 2, characterized in that, The power MOSFET unit also includes diodes D1 and D2. The control signal output terminal of the control module is connected to the anode of diode D1, and the cathode of diode D1 is connected to the controlled terminal of MOSFET Q6. The control signal output terminal of the primary protection module is connected to the anode of diode D2, and the cathode of diode D2 is connected to the controlled terminal of MOSFET Q6.

4. The recoverable secondary protection circuit according to claim 1, characterized in that, The control module includes a control chip U2 and a step-down unit. The power input terminal of the control chip U2 is connected to the power output terminal of the step-down unit. The step-down unit includes a step-down chip U1, a capacitor C3, and a resistor R7. The power input terminal of the step-down chip U1 is connected to the power output terminal of the battery module. The capacitor C3 is connected between the power output terminal of the step-down chip U1 and ground. The resistor R7 is connected between the power output terminal of the step-down chip U1 and the power input terminal of the control chip U2.

5. The recoverable secondary protection circuit according to claim 1, characterized in that, The detection signal input terminal of the primary protection module includes a current sampling port and a voltage sampling port. The status detection unit includes a current sampling unit and a voltage sampling unit. The current sampling unit includes an alloy resistor R49 and an alloy resistor R33 connected in series in the current loop. The two ends of the alloy resistor R49 are connected to the current sampling port, and the two ends of the alloy resistor R33 are connected to the detection signal input terminal of the control module. The sampling signal input terminal of the voltage sampling unit is connected to the voltage output terminal of the battery module, and the signal output terminal of the current sampling unit is connected to the voltage sampling port.

6. A recoverable secondary protection circuit according to claim 5, characterized in that, The voltage sampling port includes a first numerator port and a second numerator port. The voltage sampling unit includes resistors R38, R24, R32, R23, MOSFET Q2, and MOSFET Q3. Resistor R24 ​​is connected in parallel to one of the batteries in the battery module, and resistor R38 is connected in parallel to the other battery in the battery module. The common node between the first end of resistor R24 ​​and one of the batteries is connected to the first end of resistor R23. The second end of resistor R23 is connected to the first numerator port, and the second end of resistor R24 ​​is connected to the first numerator port. The first conducting terminal of MOSFET Q2 is connected, and the second conducting terminal of MOSFET Q2 is combined with the power output terminal of another battery to form a conducting node. The conducting node is connected to the first terminal of resistor R38, and the second terminal of resistor R38 is connected to the first conducting terminal of MOSFET Q3. The second conducting terminal of MOSFET Q3 is grounded. The controlled terminal of MOSFET Q3, the controlled terminal of MOSFET Q2, and the first terminal of resistor R32 are combined to form a connection node. The connection node is connected to the second differential numerator terminal, and the second terminal of resistor R32 is connected to the conducting node.

7. A recoverable secondary protection circuit according to claim 1, characterized in that, The primary protection module includes a battery management chip U3 and a switching element Q1. The switching element Q1 is connected in the current loop. The signal input terminal of the battery management chip U3 is connected to the first signal output terminal of the state detection module. The signal output terminal of the battery management chip U3 is connected to the controlled terminal of the switching element Q1. The switching element Q1 is a dual MOS packaged device.

8. A control method for a recoverable secondary protection circuit, characterized in that, Applied to a recoverable secondary protection circuit as described in any one of claims 1-7, the control method includes: The battery module is continuously monitored to obtain the corresponding battery state change trend, which includes at least the current change trend and the voltage change trend. The battery state change trend is integrated and processed by time series to generate the corresponding comprehensive state characterization parameters. Based on the comprehensive state characterization parameters, a matching process is performed with a preset hierarchical threshold model to determine the current state level of the battery module. The state level includes normal state, first-level abnormal state and second-level abnormal state. When the status level is a first-level abnormal state, the switch conducting element located in the current loop in the first-level protection module is cut off, and the tracking and judgment of the switch conducting element is initiated to generate the corresponding first-level protection status result. When the status level is a level 2 abnormal state, or the level 1 protection status result is a failure state, a corresponding level 2 protection trigger command is generated to perform bidirectional cut-off control on the current loop. After executing the secondary protection trigger command, the battery module is continuously monitored to obtain new comprehensive state characterization parameters. Regression analysis is performed on the new comprehensive state characterization parameters based on preset recovery judgment conditions to generate corresponding analysis results. Based on the analysis results, it is determined whether to generate a corresponding recovery control command to restore the conduction state of the current loop.

9. The control method for a recoverable secondary protection circuit according to claim 8, characterized in that, The step of generating a corresponding secondary protection trigger command when the status level is a level two abnormal state, or the level one protection status result is a failure state, includes: Based on the comprehensive state characterization parameters, the corresponding abnormal duration features and change rate features are extracted, and the abnormal duration features and change rate features are subjected to correlation analysis to generate the corresponding failure judgment feature parameters. The failure determination feature parameters are matched with a preset failure determination model to generate a corresponding matching result, and the first-level protection status result is determined as a failure state based on the matching result. If so, a corresponding trigger weight is generated based on the matching result, and a corresponding secondary protection trigger instruction is generated based on the trigger weight.

10. The control method for a recoverable secondary protection circuit according to claim 9, characterized in that, The step of performing bidirectional cutoff control on the current loop includes: Based on the secondary protection trigger command, determine whether to execute the pre-shutdown process; If so, during the pre-shutdown process, the primary protection module takes over the control action of the secondary switch management module to determine whether to bidirectionally cut off the current loop. If not, the control module takes over the control actions of the secondary switch management module to determine whether to bidirectionally cut off the current loop.

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