A current leakage monitoring and automatic circuit breaking protection circuit system

Abstract

The utility model relates to battery leakage monitoring and protection technical field, concretely relates to a current leakage monitoring and automatic circuit protection circuit system, include: a plurality of independent protection unit and a centralized management module. Each protection unit corresponds to a battery section, possesses local leakage detection and circuit breaking function. Each protection unit includes ripple injection module, phase detection module, circuit breaker executor and mechanical interlock mechanism, through the ripple injection module in the battery pack ground loop injects high frequency ripple, and phase detection module extracts the phase shift and converts into voltage signal and outputs the breaking instruction. Circuit breaker execution controls double coil magnetic latching relay action through H bridge chip, realizes the physical isolation of fault section. Mechanical interlock mechanism prevents the adjacent relay misoperation through the linkage rod, improves the system security. The centralized management module summarizes each independent protection unit fault section positioning. The system realizes the accurate positioning and quick power-off isolation of lead-acid battery pack leakage fault.

Description

Technical Field

[0001] This utility model relates to the field of battery leakage monitoring and protection technology, specifically to a current leakage monitoring and automatic circuit breaking protection circuit system. Background Technology

[0002] With the development of new energy storage systems, series lead-acid battery packs are widely used in power, communication, and transportation fields. However, due to the long-term operation of battery packs under high voltage and high current environments, problems such as insulation aging between battery segments, loose wiring, and electrolyte leakage frequently occur, easily leading to leakage faults. Traditional leakage protection methods mostly use bus-type leakage circuit breakers or centralized insulation monitoring devices. Although these can detect the overall insulation status of the system to a certain extent, they cannot achieve precise location and isolation of individual battery segments. Once a battery segment leaks, the entire system is often forced to shut down for maintenance, seriously affecting system reliability and operating efficiency. In addition, existing technologies lack physical isolation mechanisms for faulty segments, posing a risk of accidental reactivation or fault propagation. Therefore, there is an urgent need for a protection system that can achieve segmented leakage monitoring, precise location, and automatic isolation to improve the safety and maintenance efficiency of battery pack operation.

[0003] In existing technologies, leakage protection for series lead-acid battery packs mainly relies on centralized insulation monitoring or bus-type leakage circuit breakers. These solutions have the following shortcomings: First, they cannot achieve precise fault location; they can only determine whether there is leakage in the overall system, but cannot identify the specific faulty battery segment, resulting in low maintenance efficiency. Second, they lack localized disconnection execution mechanisms, requiring manual intervention or system-wide power outages after a fault occurs, affecting continuous system operation. Third, existing protection devices lack effective mechanical or electrical interlocking mechanisms, posing a risk of accidental closing or reconnection of the faulty segment to the system. Finally, centralized control systems struggle to achieve safe isolation of control signals under high-voltage environments, leading to electrical interference and safety hazards. Utility Model Content

[0004] The purpose of this invention is to provide a current leakage monitoring and automatic circuit breaking protection circuit system to solve the problem that lead-acid battery packs in the prior art are difficult to monitor leakage in segments, accurately locate leakage faults and automatically isolate them.

[0005] To solve the above-mentioned technical problems, the technical solution adopted by this utility model includes:

[0006] Multiple independent protection units, each corresponding to a first-level series lead-acid battery segment, are used to implement local leakage detection and disconnection to achieve accurate fault location;

[0007] Each independent protection unit includes:

[0008] The ripple injection module includes an inductor and a square wave generator. The inductor is connected in series with the negative ground terminal of the battery section, and the square wave generator is connected to the input terminal of the inductor.

[0009] The phase detection module includes a differential amplifier and a lock-in amplifier. The differential amplifier is connected across the two ends of the inductor, and its output is connected to the input of the lock-in amplifier.

[0010] The circuit breaker includes a dual-coil magnetic latching relay and a drive circuit. The dual-coil magnetic latching relay is connected in series in the positive circuit of the battery section, and the drive terminal of the dual-coil magnetic latching relay is connected to the drive circuit.

[0011] The mechanical interlocking mechanism includes a linkage rod fixed to the moving contact of a dual-coil magnetic latching relay, used to mechanically prevent the closure of adjacent relays;

[0012] The centralized management module connects all independent protection units via a communication bus.

[0013] Using the above technical solution, the ripple injection module is used to inject high-frequency ripple into the grounding loop, so that the leakage path generates detectable phase shift characteristics; the output of the square wave generator is connected to the input of the inductor through a coupling capacitor to block the DC component of the battery from entering the square wave generator; the output of the inductor is connected to the negative ground terminal of the battery segment through a grounding resistor to establish a reference potential.

[0014] In the above technical solution, the phase detection module is used to extract the ripple current phase offset of the lead-acid battery segment and convert it into a DC voltage signal; the reference signal input terminal of the lock-in amplifier is directly connected to the output terminal of the square wave generator to obtain the reference ripple phase.

[0015] The phase detection module also includes:

[0016] The voltage comparator has its non-inverting input connected to the phase difference output of the lock-in amplifier, and its inverting input connected to the threshold voltage to set the circuit breaker threshold. It generates a relay disconnection command based on the DC voltage signal.

[0017] Using the above technical solution, the circuit breaker actuator is used to switch the contact state magnetically after receiving the disconnection command, physically isolating the faulty battery segment from the cascaded circuit.

[0018] The driving circuit includes an H-bridge driver chip, whose input pin is connected to the output of a voltage comparator to receive circuit disconnection commands; its output pin one and output pin two are respectively connected to the two coils of a dual-coil magnetic latching relay to change the polarity of output pin one and two, control the magnetization and demagnetization of the relay coil, and drive the contacts to open and close.

[0019] In the above technical solution, the linkage rod is rigidly connected to the moving contact of the double-coil magnetic latching relay in the mechanical interlocking mechanism. The linkage rod extends into the closing slot of the adjacent relay for synchronous movement when the contact is disconnected.

[0020] When the dual-coil magnetic latching relay is disconnected, the linkage rod inserts into the slide rail of the closing slot of the adjacent relay, blocking the movement path of the closing lever. This mechanical limit prevents the adjacent relay from receiving the closing command, thus preventing the cascaded system from being mistakenly connected to the faulty section.

[0021] The above technical solution includes a centralized management module used to aggregate fault location information from each independent protection unit and coordinate the control of multiple series-connected lead-acid battery segments, including:

[0022] The multiplexer has its input terminals connected to the output terminals of all voltage comparators, and is used to receive the status signal channels of each independent protection unit.

[0023] The central processing unit (CPU) has its data exchange terminal connected to the output terminal of the multiplexer, which is used to send channel selection commands and read the detection status of a specified battery segment. The PWM output terminal of the CPU is connected to the enable terminal of all drive circuits through an optocoupler array, which is used to generate electrically isolated control pulses to ensure the safe isolation between the high-voltage battery circuit and the low-voltage control circuit.

[0024] In the above technical solution, the communication bus adopts a daisy-chain topology, and each independent protection unit is equipped with a bus transceiver to modulate the fault code signal of the unit into a differential signal for transmission; the transmitting end of the bus transceiver is connected to the receiving end of the centralized management module.

[0025] Due to the adoption of the above technical solution, the technological progress achieved by this utility model compared to the prior art is as follows:

[0026] This technical solution represents a significant advancement in the field of leakage protection for series lead-acid battery packs. Firstly, by setting up an independent protection unit for each battery segment, precise fault location and localized handling are achieved, avoiding the problem of traditional centralized monitoring failing to identify specific fault segments. Secondly, the combination of ripple injection and phase detection enables highly sensitive identification of weak leakage signals, and the extraction of phase shift characteristics through a lock-in amplifier improves detection accuracy and anti-interference capabilities. Furthermore, the cooperation between the dual-coil magnetic latching relay and the H-bridge drive circuit enables fast and reliable circuit breaking, ensuring timely isolation of faulty segments. The introduction of a mechanical interlock mechanism further enhances system safety, preventing accidental connection of faulty segments. The centralized management module achieves multi-unit coordinated control via a daisy-chain communication bus, improving the system's intelligence and scalability. These technological innovations collectively construct an efficient, safe, and intelligent battery pack leakage protection system. Attached Figure Description

[0027] The present invention will be further described below with reference to the accompanying drawings.

[0028] Figure 1 This is a schematic diagram of the current leakage monitoring and automatic circuit breaking protection circuit system of this utility model;

[0029] Figure 2 This is a schematic diagram of the circuit structure of a single independent protection unit of this utility model;

[0030] Figure 3 This is a schematic diagram of the circuit structure of the centralized management module of this utility model;

[0031] Figure 4 This is a flowchart illustrating the working process of the mechanical interlock mechanism of this utility model.

[0032] In the diagram: 1. Independent protection unit; 11. Ripple injection module; 12. Phase detection module; 13. Circuit breaker actuator; 14. Mechanical interlock mechanism; 2. Centralized management module. Detailed Implementation

[0033] The present invention will be further described in detail below with reference to embodiments:

[0034] Example 1

[0035] like Figures 1-4 As shown, this utility model provides a current leakage monitoring and automatic circuit breaking protection circuit system, including: multiple independent protection units 1 and a centralized management module 2.

[0036] In this embodiment, the lead-acid battery pack consists of four 12V / 100Ah sealed batteries connected in series, with each battery corresponding to an independent protection unit 1. The system includes: four independent protection units 1, installed on the electrodes of each battery cell; one centralized management module 2, installed in the control box; and a 48V to 5V power supply module, model LM2596S-5.0, whose input terminal is connected to the positive terminal of the first sealed battery cell and the negative terminal of the fourth sealed battery cell, and whose output terminal provides +5V power to the system.

[0037] Each independent protection unit 1 corresponds to a first-level series lead-acid battery segment, used to implement local leakage detection and disconnection to achieve accurate fault location;

[0038] Each independent protection unit 1 includes:

[0039] The ripple injection module 11 includes an inductor and a square wave generator, which are used to inject high-frequency ripple into the grounding loop to generate detectable phase shift characteristics in the leakage path; the inductor is connected in series with the negative ground terminal of the battery segment, and the square wave generator is connected to the input terminal of the inductor.

[0040] In the ripple injection module 11, the output terminal of the square wave generator is connected to the input terminal of the inductor through a coupling capacitor to block the DC component of the battery from entering the square wave generator; the output terminal of the inductor is connected to the negative ground terminal of the battery section through a grounding resistor to establish a reference potential.

[0041] In this embodiment, the square wave generator uses the NE555DR chip. Its RESET pin and VCC pin 8 are connected to a +5V power supply, the GND pin is grounded, and the output pin is connected to the input terminal of a 10μH inductor through a 0.1μF ceramic capacitor. The output terminal of the inductor is connected to the negative terminal of the first battery through a 10kΩ / 2W resistor, and a 100nF safety capacitor is connected in parallel across the inductor.

[0042] The phase detection module 12 includes a differential amplifier and a lock-in amplifier, which are used to extract the ripple current phase offset of the lead-acid battery segment and convert it into a DC voltage signal; the differential amplifier is connected across the two ends of the inductor, and the input terminal of the lock-in amplifier is connected to the output terminal of the differential amplifier.

[0043] In the phase detection module 12, the reference signal input terminal of the lock-in amplifier is directly connected to the output terminal of the square wave generator to obtain the reference ripple phase;

[0044] Phase detection module 12 also includes:

[0045] The voltage comparator's non-inverting input is connected to the phase difference output of the lock-in amplifier, and its inverting input is connected to a threshold voltage to set the circuit breaker action threshold and generate a disconnection command.

[0046] In this embodiment, the differential amplifier uses the INA188IDR chip. Its IN- pin is connected to the input terminal of the inductor via a 1kΩ resistor; its IN+ pin is connected to the output terminal of the inductor via a 1kΩ resistor; and its output pin is connected to the signal input pin of the lock-in amplifier via an RC filter network. The RC filter network consists of a 10kΩ resistor and a 100nF inductor. The lock-in amplifier uses the AD630BNZ chip. Its parameter input pin is directly connected to the output pin of the square wave generator, and its output pin is connected to the IN+ pin of the voltage comparator. The voltage comparator uses the LM393DR chip. Its IN- pin is connected to the midpoint of the adjustable resistor RV1, and the threshold voltage is set to 0.5V; its output pin is connected to the input pin of the H-bridge driver chip via a 4.7kΩ pull-up resistor.

[0047] The circuit breaker actuator 13 includes a dual-coil magnetic latching relay and a drive circuit, which is used to switch the contact state by magnetic force after receiving a disconnection command, and physically isolate the faulty battery segment from the cascaded circuit; the dual-coil magnetic latching relay is connected in series in the positive circuit of the battery segment, and the drive end of the dual-coil magnetic latching relay is connected to the drive circuit.

[0048] The drive circuit includes:

[0049] The H-bridge driver chip has its input pins connected to the output of a voltage comparator to receive circuit disconnection commands. Its output pins one and two are connected to the two coils of a dual-coil magnetic latching relay, respectively, to change the polarity of the output pins one and two, control the magnetization and demagnetization of the relay coils, and drive the contacts to open and close.

[0050] In this embodiment, the H-bridge driver chip is a DRV8833PWPR. Its VM pin is connected to the positive terminal of the first battery via a 10A fuse. The IN1 and IN2 pins are connected to the OUT pins of the LM393DR, respectively. The OUT1 pin is connected to the coil terminal A1 of the dual-coil magnetic latching relay, and the OUT2 pin is connected to the coil terminal A2 of the dual-coil magnetic latching relay. A 1N5819 diode is connected in parallel between the coil terminals A1 and A2 of the dual-coil magnetic latching relay. Its common terminal is connected to the positive terminal of the first battery, and its normally open terminal is connected to the output positive terminal of the cascaded battery pack.

[0051] The mechanical interlock mechanism 14 includes a linkage rod fixed on the moving contact of the dual-coil magnetic latching relay, the linkage rod extending into the closing slot of the adjacent relay for mechanically preventing the adjacent relay from closing;

[0052] In the mechanical interlock mechanism 14, the linkage rod is rigidly connected to the moving contact of the double coil magnetic latching relay for synchronous movement when the contact is broken;

[0053] When the dual-coil magnetic latching relay is disconnected, the linkage rod inserts into the slide rail of the closing slot of the adjacent relay, blocking the movement path of the closing lever. This mechanical limit prevents the adjacent relay from receiving the closing command, thus preventing the cascaded system from being mistakenly connected to the faulty section.

[0054] In this embodiment, the linkage rod is an L-shaped rod made of 304 stainless steel. One end of the rod is bolted to the moving contact shaft of the double-coil magnetic latching relay, and the other end extends into the closing slot of the double-coil magnetic latching relay in the adjacent independent protection unit 1. A spring steel lever is provided in the closing slot of the double-coil magnetic latching relay, and the gap between the linkage rod and the spring steel lever is 0.4mm.

[0055] The centralized management module 2 connects to all independent protection units 1 via a communication bus, and is used to summarize the fault location of each independent protection unit 1 and coordinate the control of multiple series lead-acid battery segments.

[0056] Centralized management module 2 includes:

[0057] The multiplexer has its input terminals connected to the output terminals of all voltage comparators, and is used to receive the status signal channels of each independent protection unit 1.

[0058] The central processing unit (CPU) has its data exchange terminal connected to the output terminal of the multiplexer, which is used to send channel selection commands and read the detection status of a specified battery segment. The PWM output terminal of the CPU is connected to the enable terminal of all drive circuits through an optocoupler array, which is used to generate electrically isolated control pulses to ensure the safe isolation between the high-voltage battery circuit and the low-voltage control circuit.

[0059] In this embodiment, the multiplexer uses a CD4051BE chip. Its pins X0-X3 are connected to the output pins of the LM393DR, which represents four single-stage series-connected lead-acid battery cells. Its address pins A / B / C are connected to pins PA0-PA2 of the central processing unit (CPU), and its output pins are connected to pin PA3 of the CPU. The CPU is an STM32F030F4P6. Its VDD pin is connected to a +5V power supply, and its VDDA pin is connected to a +5V power supply via a 10μF tantalum capacitor. Pins PA4-PA7 are enabled via an optocoupler array. The optocoupler array is a TLP281-4. Its input pins IN1+-IN4+ are connected to pins PA4-PA7 of the STM32F030F4P6, and its output pins OUT1-OUT4 are connected to the EN pin of the DRV8833PWPR, which represents four single-stage series-connected lead-acid battery cells.

[0060] The communication bus adopts a daisy-chain topology. Each independent protection unit 1 is equipped with a bus transceiver to modulate the fault code signal of this unit into a differential signal for transmission. The transmitting end of the bus transceiver is connected to the receiving end of the centralized management module 2.

[0061] In this embodiment, the bus transceiver is a MAX485ESA+, with one MAX485ESA+ chip installed for each of the four lead-acid battery segments connected in series, and the four MAX485ESA+ chips are cascaded in sequence.

[0062] The working principle of this current leakage monitoring and automatic circuit breaking protection circuit system will be explained in detail below.

[0063] This system achieves accurate detection and rapid isolation of leakage faults by setting an independent protection unit 1 for each series-connected lead-acid battery segment. Each unit is injected with a high-frequency ripple signal into the grounding circuit by a ripple injection module 11. When a battery segment experiences leakage, the leakage path causes a phase shift in the ripple current. The phase detection module 12 extracts this phase shift using a differential amplifier and a lock-in amplifier, converts it into a DC voltage signal, and compares it with a set threshold to determine if leakage has occurred. Once an anomaly is detected, the voltage comparator outputs a disconnect command, and the drive circuit controls the dual-coil magnetic latching relay to quickly disconnect the positive circuit of the faulty battery segment, achieving physical isolation. Simultaneously, the mechanical interlock mechanism 14 prevents adjacent relays from closing via a linkage rod, preventing the faulty segment from reconnecting to the system. The centralized management module 2 polls the status of each unit through a multiplexer and communicates and controls with each unit through optocoupler isolation and an RS-485 bus, ensuring safe isolation of high and low voltage circuits and coordinated system operation. This solution effectively improves the safety, reliability, and maintenance efficiency of the battery pack.

[0064] This technical solution has achieved significant technical results in practical applications. Firstly, fault location accuracy is greatly improved, allowing maintenance personnel to quickly identify and replace faulty battery segments, significantly reducing system downtime and improving operational efficiency. Secondly, through localized circuit breaker execution and mechanical interlocking mechanisms, the risk of accidental reclosing and cascading propagation of faulty segments is completely eliminated, enhancing system safety and stability. Furthermore, the centralized management module enables unified monitoring and coordinated control of multiple battery segments, facilitating system integration and remote management. The application of ripple injection and phase detection technologies gives the system higher sensitivity to weak leakage currents, enabling early warnings in the initial stages of faults and preventing the escalation of accidents. This solution effectively solves the problems of inaccurate location, delayed response, and poor safety inherent in traditional technologies, providing a reliable guarantee for the safe operation of series-connected lead-acid battery packs, and has good promotional value and application prospects.

[0065] The present invention has been described in detail above. However, modifications or improvements can be made to it, which will be obvious to those skilled in the art. Therefore, any modifications or improvements that do not depart from the spirit of the present invention are within the protection scope of the present invention.

Claims

1. A current leakage monitoring and automatic circuit breaking protection circuit system, characterized in that, include: Multiple independent protection units (1), each of the independent protection units (1) corresponds to a first-level series lead-acid battery segment, used to implement local leakage detection and disconnection to achieve accurate fault location; Each of the independent protection units (1) includes: The ripple injection module (11) includes an inductor and a square wave generator. The inductor is connected in series with the negative ground terminal of the battery segment, and the square wave generator is connected to the input terminal of the inductor. The phase detection module (12) includes a differential amplifier and a lock-in amplifier. The differential amplifier is connected across the two ends of the inductor, and its output is connected to the input of the lock-in amplifier. The circuit breaker (13) includes a dual-coil magnetic latching relay and a drive circuit. The dual-coil magnetic latching relay is connected in series in the positive circuit of the battery section, and the drive terminal of the dual-coil magnetic latching relay is connected to the drive circuit. The mechanical interlock mechanism (14) includes a linkage rod fixed on the moving contact of the dual-coil magnetic latching relay for mechanically blocking the closing of adjacent relays; The centralized management module (2) connects all the independent protection units (1) via a communication bus.

2. The current leakage monitoring and automatic circuit breaking protection circuitry of claim 1, wherein: The ripple injection module (11) is used to inject high-frequency ripple into the grounding loop, so that the leakage path produces detectable phase shift characteristics. The output terminal of the square wave generator is connected to the input terminal of the inductor through a coupling capacitor to block the DC component of the battery from entering the square wave generator; the output terminal of the inductor is connected to the negative ground terminal of the battery segment through a grounding resistor to establish a reference potential.

3. The current leakage monitoring and automatic circuit protection circuitry of claim 1, wherein: The phase detection module (12) is used to extract the ripple current phase offset of the lead-acid battery segment and convert it into a DC voltage signal; the reference signal input terminal of the lock-in amplifier is directly connected to the output terminal of the square wave generator to obtain the reference ripple phase. The phase detection module (12) further includes: The voltage comparator has its non-inverting input connected to the phase difference output of the lock-in amplifier, and its inverting input connected to a threshold voltage to set the circuit breaker threshold and generate a relay disconnection command based on the DC voltage signal.

4. The current leakage monitoring and automatic circuit protection circuitry of claim 1, wherein: The circuit breaker (13) is used to switch the contact state by magnetic force after receiving the disconnection command, and physically isolate the faulty battery segment from the cascaded circuit. The driving circuit includes an H-bridge driver chip, whose input pin is connected to the output of a voltage comparator to receive circuit disconnection commands; its output pin one and output pin two are respectively connected to the two sets of coils of the dual-coil magnetic latching relay to change the polarity direction of output pin one and two, control the magnetization and demagnetization of the relay coil, and drive the contacts to open and close.

5. The current leakage monitoring and automatic circuit protection circuitry of claim 1, wherein: In the mechanical interlock mechanism (14), the linkage rod is rigidly connected to the moving contact of the double coil magnetic latching relay, and the linkage rod extends into the closing slot of the adjacent relay for synchronous movement when the contact is disconnected; When the dual-coil magnetic latching relay is disconnected, the linkage rod is inserted into the slide rail of the closing slot of the adjacent relay, blocking the movement path of the closing lever. This mechanically limits the adjacent relay from receiving the closing command, preventing the cascaded system from being mistakenly connected to the faulty section.

6. The current leakage monitoring and automatic circuit protection circuitry of claim 4, wherein: The centralized management module (2) is used to summarize the fault location of each independent protection unit (1) and coordinate the control of multiple series-connected lead-acid battery segments, including: A multiplexer, whose input is connected to the output of all the voltage comparators, is used to receive the status signal channels of each independent protection unit (1); The central processing unit (CPU) has its data exchange terminal connected to the output terminal of the multiplexer, and is used to send channel selection commands and read the detection status of a specified battery segment. The PWM output terminal of the CPU is connected to the enable terminal of all the drive circuits through an optocoupler array, and is used to generate electrically isolated control pulses to ensure safe isolation between the high-voltage battery circuit and the low-voltage control circuit.

7. The current leakage monitoring and automatic circuit protection circuitry of claim 1, wherein: The communication bus adopts a daisy chain topology. Each independent protection unit (1) is equipped with a bus transceiver to modulate the fault code signal of the unit into a differential signal for transmission. The transmitting end of the bus transceiver is connected to the receiving end of the centralized management module (2).

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