Insulation detection device under scene of series connection of multiple energy storage systems and detection method thereof

Abstract

The invention relates to the field of circuit performance detection, in particular to an insulation detection device under a scene of series connection of multiple energy storage systems and a detection method thereof. The system configuration signal processing module is formed by connecting a plurality of energy storage subsystems in series, each energy storage subsystem is divided into a head end system, a middle system and a tail end system, the insulation detection modules are connected with the energy storage subsystems in a one-to-one correspondence mode, and each insulation detection module comprises a detection mode switching module, a voltage division module and a data sampling module; the voltage division modules of all the energy storage subsystems and the switch units form an electric connection loop; on-off time sequences of all the switch units are controlled according to preset logic, voltage sampling values of a voltage dividing module of a head end system in different detection modes are obtained through a data sampling module, and then insulation resistance values of a total positive end and a total negative end to a machine shell are calculated according to the voltage sampling values through a signal processing module. The system can be adapted to a series connection scene of a plurality of energy storage subsystems, and the insulation resistance detection of the total anode end and the total cathode end of the whole series connection system on the machine shell is accurately realized.

Description

Technical Field

[0001] This invention relates to the field of circuit performance testing, and in particular to an insulation testing device and method for multi-energy storage systems in series. Background Technology

[0002] In the field of energy storage, high-voltage energy storage systems with battery management systems (BMS) are the core equipment for realizing the storage, dispatch, and efficient utilization of electrical energy. Their operational safety directly affects the stable operation of the entire energy storage power station. Specifically, the BMS needs to monitor the insulation resistance between the battery's positive terminal (B+) and the casing, as well as between the battery's negative terminal (B-) and the casing in real time. This step is crucial for preventing safety accidents such as leakage, short circuits, and even fires caused by insulation degradation, and is also a fundamental requirement for ensuring the long-term reliable operation of the system.

[0003] In scenarios where a single energy storage system operates independently, existing insulation detection devices can calculate insulation impedance through methods such as preset voltage divider resistor networks, signal acquisition, and computational amplification. At this time, the circuit signal reference is stable, and the detection error can be controlled within the allowable range of engineering, which can basically meet the safety monitoring needs of a single system.

[0004] However, as energy storage applications place increasing demands on capacity and voltage levels, the use of multiple energy storage systems in series has become a common configuration (e.g., increasing the total output voltage of the system to adapt to high-voltage loads, or expanding the overall energy storage capacity to meet large-scale power supply needs). In this series-connected scenario, existing insulation detection devices suffer from insurmountable technical flaws: not only does the detection error of insulation impedance increase dramatically, but detection function failures or false alarms also occur frequently. This makes it impossible for maintenance personnel to accurately determine the actual insulation status of the series-connected system, severely weakening the system's safety protection capabilities, and potentially leading to unnecessary shutdowns due to misjudgments or creating safety hazards due to missed detections.

[0005] Analysis revealed two main causes of the problem: First, multiple series-connected energy storage systems require interconnecting their casing grounding points to ensure grounding uniformity. This connection method disrupts the signal reference of the insulation detection device under a single system, causing the voltage divider signal and impedance feedback signal acquired by the detection circuit to lose their stable reference, directly interfering with the calculation logic of insulation impedance. Second, the overall output voltage increases significantly after multiple systems are connected in series. Excessively high voltage signals can exceed the rated operating range of core components such as voltage divider resistors and isolation amplifiers in the original detection circuit, leading to a decrease in the signal processing accuracy of the components, or even causing abnormal circuit operation, further exacerbating detection errors or causing the detection function to malfunction.

[0006] In summary, existing insulation testing devices can only be adapted to single-system independent operation scenarios and cannot be compatible with the application requirements of multiple systems connected in series. There is a lack of effective solutions to the technical pain points of "grounding potential interference" and "high-voltage signal influence" in series scenarios, making it difficult to meet the safety monitoring requirements of large-scale energy storage systems. There is an urgent need for an insulation testing solution that can be adapted to both single-system and multi-system series scenarios and can ensure detection accuracy under different grounding potential environments. Summary of the Invention

[0007] Therefore, the technical problem to be solved by the present invention is to overcome the problems that the insulation detection error of a single system in the existing energy storage system is controllable, but when multiple systems are connected in series, the detection error is large or even fails and false alarms are caused by the connection of grounding points and the increase of series voltage. Furthermore, the circuit is not applicable when the grounding potential is different and the insulation impedance of multiple systems cannot be measured.

[0008] To address the aforementioned technical problems, this invention provides an insulation detection device and method for a series multi-energy storage system scenario. The insulation detection device includes a signal processing module and multiple insulation detection modules. Each insulation detection module is connected to any subsystem in the series energy storage system and includes: a detection mode switching module, a voltage divider module, a data sampling module, a positive terminal, a negative terminal, and a grounding terminal. Wherein, the positive terminal is connected to the positive terminal B+ of the battery pack in the corresponding subsystem, and the negative terminal is connected to the negative terminal B- of the battery pack in the corresponding subsystem; the grounding terminal is connected to the battery pack housing grounding terminal EGND in the corresponding subsystem, and the grounding terminals in all insulation detection modules are connected. The detection mode switching module includes multiple switching units, which are connected to the voltage divider module to form an electrical connection loop. The output terminal of the voltage divider module is connected to the input terminal of the data sampling module, and the output terminal of the data sampling module is connected to the signal processing module. The on / off state of multiple switching units of each insulation detection module is controlled. The voltage value on the voltage divider module is collected by the corresponding data sampling module. The position of the corresponding subsystem in the whole series energy storage system is determined according to the comparison result of the voltage value. The positive terminal of the insulation detection module corresponding to the first subsystem is connected to the total positive terminal of the series energy storage system, and the negative terminal of the insulation detection module corresponding to the last subsystem is connected to the total negative terminal of the series energy storage system. By controlling the on / off timing of multiple switching units of all insulation detection modules according to preset timing control logic, the data sampling module of the insulation detection module corresponding to the first subsystem obtains the voltage sampling value of its voltage divider module in the detection mode corresponding to different on / off timing. The signal processing module calculates the insulation impedance value of the total positive terminal and the total negative terminal of the entire series energy storage system to the casing based on the voltage sampling value.

[0009] In one embodiment of the present invention, the detection mode switching module includes a first switching unit, a second switching unit, and a third switching unit. Each switching unit includes a relay. The voltage input terminal of the first relay in the first switching unit is connected to the positive terminal. The voltage output terminal of the second relay in the second switching unit is connected to the negative terminal. The third relay in the third switching unit is connected to the ground terminal.

[0010] In one embodiment of the present invention, the voltage divider module includes a first resistor, a second resistor, a third resistor, and a fourth resistor. One end of the first resistor is connected to the voltage output terminal of the first relay, and the other end is connected to the second resistor and the input terminal of the data sampling module. The other end of the second resistor is connected to the common connection point of the third resistor, the voltage input terminal of the third relay, and the ground terminal of the data sampling module. The other end of the third resistor is connected to the voltage input terminal of the second relay. One end of the fourth resistor is connected to the ground terminal of the data sampling module, and the other end is connected to the voltage output terminal of the second relay.

[0011] In one embodiment of the present invention, the data sampling module is driven by a timing control signal, and according to the detection task requirements, its enable terminal is applied with a corresponding periodic level signal to control its sampling period.

[0012] In one embodiment of the present invention, each switching unit includes a driving unit. The input terminal of the first driving unit in the first switching unit receives a first control signal, and the control output terminal of the first driving unit is connected to the control terminal of the first relay. The input terminal of the second driving unit in the second switching unit receives a second control signal, and the control output terminal of the second driving unit is connected to the control terminal of the second relay. The third driving unit in the third switching unit receives a third control signal, and the control output terminal of the third driving unit is connected to the control terminal of the third relay.

[0013] In one embodiment of the present invention, the first driving unit includes a first NMOS transistor, a fifth resistor, and a sixth resistor. One end of the fifth resistor receives the first control signal, and the other end is connected to the gate of the first NMOS transistor and one end of the sixth resistor. The other end of the sixth resistor is connected to the source of the first NMOS transistor and grounded. The drain of the first NMOS transistor is connected to the control terminal of the first relay.

[0014] In one embodiment of the present invention, the second driving unit includes a second NMOS transistor, a seventh resistor, and an eighth resistor. One end of the seventh resistor receives the second control signal, and the other end is connected to the gate of the second NMOS transistor and one end of the eighth resistor. The other end of the eighth resistor is connected to the source of the second NMOS transistor and grounded. The drain of the second NMOS transistor is connected to the control terminal of the second relay.

[0015] In one embodiment of the present invention, the third driving unit includes a third NMOS transistor, a ninth resistor, and a tenth resistor. One end of the ninth resistor receives the third control signal, and the other end is connected to the gate of the third NMOS transistor and one end of the tenth resistor. The other end of the tenth resistor is connected to the source of the third NMOS transistor and grounded. The drain of the third NMOS transistor is connected to the control terminal of the third relay.

[0016] Furthermore, the present invention also provides a detection method applied to the insulation detection device, comprising the following steps: Send the first set of timing control signals to each energy storage subsystem to control the switching units of all energy storage subsystems to close according to a predetermined logic, so that the voltage divider modules of all energy storage subsystems are connected in parallel between the total positive terminal of the series energy storage system and the common chassis ground terminal through the closed switches, and collect the voltage of the voltage divider module in the first subsystem and record it as the first detection voltage; Send the second set of timing control signals to each energy storage subsystem to control the switching units of all energy storage subsystems to close according to a predetermined logic, so that the voltage divider modules of all energy storage subsystems are connected in parallel to the total negative terminal of the series energy storage system and the common chassis ground terminal through the closed switches, and collect the voltage of the voltage divider module in the first subsystem and record it as the second detection voltage; Based on the first detection voltage and the second detection voltage, the insulation resistance values ​​of the total positive terminal and the total negative terminal of the series energy storage system to the chassis ground are calculated. The insulation impedance value obtained by the solution is compared with the preset insulation safety threshold to obtain the insulation performance test results of the multi-energy storage system connected in series.

[0017] In one embodiment of the present invention, the detection method further includes a subsystem location determination step in the series energy storage system, as follows: In the series energy storage system, each adjacent subsystem establishes a communication connection, all subsystems are powered on at the same time, and the two are confirmed to be in a state of waiting for detection through interaction, and the timing logic of synchronous switch control is used. The detection mode switching modules of all subsystems are turned on to construct a complete voltage sampling circuit, including: closing the solid-state relay on the positive terminal side to connect the positive terminal of each subsystem to the series main circuit; closing the solid-state relay on the negative terminal side to connect the negative terminal of each subsystem to the series main circuit; and closing the solid-state relay on the ground terminal side to connect the voltage divider module of each subsystem to the common ground terminal. Each subsystem acquires the output voltage of the voltage divider module through its own data sampling module. This voltage value reflects the potential state of the subsystem in the series circuit. Subsystems with preset non-zero output values ​​are identified as the first-end system in the series circuit. The relay on the specific grounding side of the first-end system is driven to disconnect, cutting off part of the circuit between the first end and the common ground. The output voltage of the data sampling modules of the remaining subsystems is acquired again. Subsystems with zero output values ​​are identified as the last-end system in the series circuit. The remaining subsystems with output values ​​that are neither the preset non-zero value of the first end nor the zero value of the last end are identified as intermediate systems in the series circuit.

[0018] Compared with the prior art, the above-described technical solution of the present invention has the following advantages: This invention is adaptable to multi-system series applications and effectively solves the problems of large insulation detection errors or even false alarms caused by interconnected grounding points and increased series voltage in existing technologies. By setting up multiple relays, combined with data sampling modules and voltage divider modules, and using CAN communication between systems for coordinated control, the invention constructs different detection loops to calculate insulation impedance by controlling the on and off of solid-state relays in a specific sequence. Even in systems with different grounding potentials, it can achieve control logic and detection accuracy similar to a single system, successfully overcoming the core technical challenge of inaccurate insulation impedance measurement when multiple systems are used in series. Attached Figure Description

[0019] To make the content of this invention easier to understand, the invention will be further described in detail below with reference to specific embodiments and accompanying drawings.

[0020] Figure 1 This is a basic principle block diagram of the insulation detection device for a single energy storage system provided in the embodiments of the present invention; Figure 2 This is a schematic diagram of an insulation detection device for a single energy storage system provided in an embodiment of the present invention; Figure 3 yes Figure 2 The circuit structure diagram of the insulation detection device is shown below. Figure 4 This is a schematic diagram of an insulation detection device structure provided in an embodiment of the present invention for a scenario in which multiple energy storage systems are connected in series. Figure 5 Is with Figure 4The diagram shows a flow chart of the insulation testing method adapted to the insulation testing device. Figure 6 This is a schematic diagram of the circuit structure of the insulation detection device in the series operation scenario of the dual energy storage system provided in the embodiments of the present invention.

[0021] Explanation of reference numerals in the accompanying drawings: 1. Energy storage system; 11. First-end system; 12. Intermediate system; 13. End system; 10. Insulation detection module; 101. Detection mode switching module; 1011. First switching unit; 1012. Second switching unit; 1013. Third switching unit; 102. Voltage divider module; 103. Data sampling module; 20. Signal processing module. Detailed Implementation

[0022] The present invention will be further described below with reference to the accompanying drawings and specific embodiments, so that those skilled in the art can better understand and implement the present invention. However, the embodiments described are not intended to limit the present invention.

[0023] Figure 1 A schematic diagram of an insulation detection circuit for a single energy storage system is shown. In this circuit, the high-voltage positive terminal B+ and the negative terminal B- of energy storage system 1 constitute the total battery voltage. The chassis grounding terminal EGND is the system's safety grounding terminal. Under normal operating conditions, the high-voltage circuit (B+, B-) and the chassis must be electrically isolated through an insulating medium (such as the battery pack casing insulation material, the high-voltage cable insulation sheath, etc.) to prevent the high voltage from forming a leakage path to the chassis.

[0024] insulation resistance Essentially, it is the total equivalent impedance of the insulation layer and potential leakage path between the positive terminal B+ and the chassis ground terminal EGND, and the insulation impedance. Essentially, it is the total equivalent impedance of the insulation layer and potential leakage current path between the negative terminal B- and the chassis grounding terminal EGND. These two are the core parameters characterizing the insulation performance of the energy storage system.

[0025] according to Figure 1 Given the circuit structure, when the chassis ground terminal EGND is normally connected to the chassis, analyze the entire voltage divider circuit. Its total impedance includes the impedance of the upper half branch connected in series. and lower half branch impedance Composition, in which: , ; According to Kirchhoff's voltage law, the circuit output voltage in this state is... Because the equation includes insulation resistance , These two unknowns cannot be solved directly.

[0026] To eliminate the coupling of unknown quantities, an auxiliary detection state needs to be introduced: temporarily disconnect the connection between the chassis ground terminal EGND and the chassis. , Because it is disconnected from the grounding loop and loses its voltage-dividing effect, the total circuit impedance simplifies to: In this state, the circuit output voltage ; Given voltage divider resistors ( , , , ), battery voltage The output voltage is actually measured using equipment such as a high-voltage multimeter. By combining the two formulas above to construct a system of equations and solving it, the insulation resistance can be obtained. and The specific value; the insulation resistance , By comparing the insulation impedance with the safety threshold corresponding to the energy storage system, the compliance of the system's insulation performance can be determined.

[0027] Based on the aforementioned insulation detection circuit principle for a single energy storage system, this embodiment provides an insulation detection device suitable for a single energy storage system (such as...). Figure 2 As shown, the insulation detection accuracy is improved through hardware architecture optimization. The circuit includes an insulation detection module 10 and a signal processing module 20. The insulation detection module 10 includes a detection mode switching module 101, a voltage divider module 102, and a data sampling module 103. The insulation detection function is achieved through precise electrical connections between these modules. The specific structure and connection relationships are as follows: The detection mode switching module 101 includes multiple switching units. Its core function is to realize the on / off control and mode switching of the detection circuit. The module is connected to the positive terminal B+, negative terminal B- and the chassis grounding terminal EGND of the energy storage system 1 through the multiple switching units respectively, providing a switchable path selection for the construction of the subsequent voltage divider circuit, and ensuring that different detection scenarios of the positive terminal B+ and negative terminal B- to the chassis grounding terminal EGND can be covered by adjusting the switching on / off timing. The voltage divider module 102 is connected to the plurality of switching units to form a closed electrical connection loop. The output terminal of the voltage divider module 102 is connected to the input terminal of the data sampling module 103. Under different on / off combinations of the plurality of switching units, the insulation impedance between the positive terminal B+ and the negative terminal B- of the energy storage system and the chassis ground terminal EGND is converted into a measurable analog voltage signal. That is, through impedance matching of the voltage divider resistor network, the voltage signal amplitude is kept within the effective detection range of the data sampling module, achieving a linear conversion between "insulation impedance" and "voltage signal". The output terminal of the data sampling module 103 is connected to the signal processing module 20, transmitting the sampled analog voltage signal to the signal processing module 20. By controlling the on / off timing of the multiple switching units according to the preset control logic, the voltage signal of the voltage divider module 102 under different on / off timing detection modes is obtained by the data sampling module 103. The signal processing module 20 calculates the insulation resistance values ​​of the positive terminal B+ and negative terminal B- of the energy storage system 1 to the casing based on the voltage signal.

[0028] Furthermore, such as Figure 3 As shown, the detection mode switching module 101 specifically includes a first switching unit 1011, a second switching unit 1012, and a third switching unit 1013. Each switching unit includes a relay and a drive unit. The drive unit converts weak control signals into high-voltage drive signals to achieve precise control of the relay.

[0029] The first relay in the first switching unit 1011 ( Figure 3 The voltage input terminal (pin 5) of the solid-state relay U1 is connected to the positive terminal B+. The input terminal of the first drive unit in the first switching unit 1011 receives the on / off signal CTR B+ of the solid-state relay U1. The control output terminal of the first drive unit is connected to the control terminal (pin 2) of the solid-state relay U1. By turning the solid-state relay U1 on or off, the path between the positive terminal B+ and the voltage divider module 102 is switched. That is, when the solid-state relay U1 is on, the positive terminal B+ is connected to the voltage divider circuit, providing positive power to the circuit; when the solid-state relay U1 is off, the positive terminal B+ is disconnected from the voltage divider circuit, avoiding signal interference in the non-detection state.

[0030] The second relay in the second switching unit 1012 ( Figure 3The voltage output terminal (pin 4) of the solid-state relay U2 is connected to the negative terminal B-. The input terminal of the second drive unit in the second switching unit 1012 receives the on / off signal CTR B- of the solid-state relay U2. The control output terminal of the second drive unit is connected to the control terminal (pin 2) of the solid-state relay U2. The on / off state of the negative terminal B- and the voltage divider module 102 is controlled by the on / off state of the solid-state relay U2. When the solid-state relay U2 is on, the negative terminal B- is connected to the voltage divider circuit, forming a current path from the positive terminal B+ through the voltage divider module 102 to the negative terminal B-. When the solid-state relay U2 is off, the negative terminal B- is disconnected from the circuit, which can be used to detect the insulation status of the positive terminal B+ to the chassis ground terminal EGND, improving the flexibility of the detection mode.

[0031] The third relay in the third switching unit 1013 ( Figure 3 The solid-state relay U3 is connected to the chassis ground terminal EGND. The third drive unit in the third switch unit 1013 receives the on / off signal CTR E of the solid-state relay U3, and the control output terminal of the third drive unit is connected to the control terminal (pin 2) of the solid-state relay U3. When the solid-state relay U3 is on, the voltage divider circuit is electrically connected to the chassis ground terminal EGND, and the insulation resistance of the positive terminal B+ and the negative terminal B- to the chassis ground terminal EGND can be directly measured; when the solid-state relay U3 is off, it can be used to calibrate the zero drift error of the voltage divider module 102, further improving the detection accuracy.

[0032] The first driving unit includes a first NMOS transistor Q1, a fifth resistor R5, and a sixth resistor R6. One end of the fifth resistor R5 receives the on / off signal CTR B+ of the solid-state relay U1, and the other end is connected to the gate of the first NMOS transistor Q1 and one end of the sixth resistor R6. The other end of the sixth resistor R6 is connected to the source of the first NMOS transistor Q1 and grounded to GND. The drain of the first NMOS transistor Q1 is connected to the control terminal (pin 2) of the solid-state relay U1.

[0033] The second driving unit includes a second NMOS transistor Q2, a seventh resistor R7, and an eighth resistor R8. One end of the seventh resistor R7 receives the on / off signal CTR B- from the solid-state relay U2, and the other end is connected to the gate of the second NMOS transistor Q2 and one end of the eighth resistor R8. The other end of the eighth resistor R8 is connected to the source of the second NMOS transistor Q2 and grounded. The drain of the second NMOS transistor Q2 is connected to the control terminal (pin 2) of the solid-state relay U2.

[0034] The third driving unit includes a third NMOS transistor Q3, a ninth resistor R9, and a tenth resistor R10. One end of the ninth resistor R9 receives the on / off signal CTRE of the solid-state relay U3, and the other end is connected to the gate of the third NMOS transistor Q3 and one end of the tenth resistor R10. The other end of the tenth resistor R10 is connected to the source of the third NMOS transistor Q3 and grounded. The drain of the third NMOS transistor Q3 is connected to the control terminal (pin 2) of the solid-state relay U3.

[0035] When the control signals (CTR B+, CTR B-, CTR E) are at an invalid level (such as low level or floating), the gates of the first NMOS transistor Q1, the second NMOS transistor Q2, and the third NMOS transistor Q3 may develop floating voltages due to external noise, parasitic capacitance coupling, etc., causing the MOS transistors to be falsely turned on. To avoid this situation, resistors R6~R10 reliably pull down the gate voltage of the MOS transistors to the source level (i.e., ground level), ensuring that when the control signal is invalid, the gate-source voltage is always 0V, and the MOS transistors are in a completely off state. This prevents the solid-state relays (U1, U2, U3) from being abnormally turned on due to false triggering at the hardware level, ensuring the reliability of the circuit logic.

[0036] The data sampling module 103 is an isolation amplifier. The voltage divider module 102 includes a first resistor R1, a second resistor R2, a third resistor R3, and a fourth resistor R4. One end of the first resistor R1 is connected to the voltage output terminal of the solid-state relay U1, and the other end is connected to the second resistor R2 and the input terminal (VIN) of the data sampling module 103. The other end of the second resistor R2 is connected to the common connection point of the third resistor R3, the voltage input terminal (pin 5) of the solid-state relay U3, and the ground terminal (GND1) of the data sampling module 103. The other end of the third resistor R3 is connected to the voltage input terminal (pin 5) of the solid-state relay U2. One end of the fourth resistor R4 is connected to the ground terminal (GND1) of the data sampling module 103, and the other end is connected to the voltage output terminal (pin 4) of the solid-state relay U2.

[0037] In addition, the power supply terminal VDD1 of the data sampling module 103 is connected to a 5V isolated power supply (SIG_5V) and grounded to ground level (SIG_5V_GND) through capacitor C1. Its power supply terminal VDD2 is connected to a 3.3V power supply voltage to provide it with operating voltage, and at the same time, VDD2 is grounded to ground GND through capacitor C2.

[0038] The enable terminal (SHTD) and ground terminal GND1 of the data sampling module 103 are connected together and connected to a low level SIG_5V_GND. When the SHTD terminal is connected to a low level SIG_5V_GND, the data sampling module 103 is in working state. According to the detection task requirements, a corresponding periodic working level is applied to the SHTD terminal of the data sampling module 103.

[0039] Optionally, the signal processing module 20 is the control terminal of the energy storage system 1 or an independent control chip of the peripheral device, including but not limited to a PLC controller or an embedded microcomputer processor. The positive differential signal output terminal (OUT1P) and the negative differential signal output terminal (OUT1N) of the data sampling module 103 are connected to the differential signal input terminal of the signal processing module 20 to realize the differential transmission of the voltage sampling signal output by the voltage divider module 102 to the signal processing module 20. This connection method can effectively suppress common-mode interference, ensure the accuracy and stability of the sampling signal during transmission, and provide reliable data input for subsequent insulation impedance calculation.

[0040] Based on the insulation monitoring device for a single energy storage system described above, this embodiment also provides an insulation detection method applied to the device, the implementation steps of which are as follows: Resistors R5, R7, and R9 receive on / off signals CTR B+, CTR B-, and CTR E respectively, causing solid-state relays U1 and U3 to be in a conducting state and solid-state relay U2 to be in a closed state. In this state, after the circuit stabilizes, the data sampling module 103 acquires the voltage signal across the second resistor R2, and records this voltage as... : , in, This represents the insulation resistance of the casing relative to the positive terminal B+. This represents the insulation resistance of the casing relative to the negative terminal B-. Battery voltage; Keep solid-state relays U1 and U3 in the ON state, and switch solid-state relay U2 to the ON state. After the circuit stabilizes, the voltage signal across the second resistor R2 is collected again through the data sampling module 103, and this voltage is recorded as... : ,in, This indicates the parallel resistance value of the third resistor R3 and the fourth resistor R4; By combining the two formulas above to construct a system of equations, and then solving the system using the known voltage divider resistors (R1~R4), the insulation resistance can be obtained. and The specific value; the insulation resistance , By comparing the insulation impedance with the safety threshold corresponding to the energy storage system, the compliance of the system's insulation performance can be determined.

[0041] After further optimizing the above-mentioned insulation testing device applicable to a single energy storage system, this embodiment also provides an insulation testing device applicable to multiple energy storage systems operating in series, such as... Figure 4 As shown, it includes multiple insulation detection modules 10 and signal processing modules 20. Each insulation detection module 10 is connected to any subsystem in the series energy storage system and includes: a detection mode switching module 101, a voltage divider module 102, a data sampling module 103, a positive terminal, a negative terminal, and a ground terminal; preferably, the data sampling module 103 is an isolation amplifier.

[0042] Wherein, the positive terminal is connected to the positive terminal B+ of the battery pack in the corresponding subsystem, and the negative terminal is connected to the negative terminal B- of the battery pack in the corresponding subsystem; the grounding terminal is connected to the battery pack housing grounding terminal EGND in the corresponding subsystem, and the grounding terminals in all insulation detection modules 10 are connected. The detection mode switching module 101 includes multiple switching units, which are connected to the voltage divider module 102 to form an electrical connection loop. The output terminal of the voltage divider module 102 is connected to the input terminal of the data sampling module 103, and the output terminal of the data sampling module 103 is connected to the signal processing module 20. The on / off state of multiple switching units in each insulation detection module 10 is controlled. The voltage value on the voltage divider module 102 is collected by the corresponding data sampling module 103. Based on the comparison result of the voltage value, the position of the corresponding subsystem in the entire series energy storage system is determined. The positive terminal of the insulation detection module 10 corresponding to the first subsystem is connected to the total positive terminal of the series energy storage system, and the negative terminal of the insulation detection module 10 corresponding to the last subsystem is connected to the total negative terminal of the series energy storage system. In this way, the series energy storage system is configured as a first-end system 11, an intermediate system 12, and a last-end system 13. The positive terminal B+ of the first-end system 11 is the total positive terminal of the series energy storage system, the negative terminal B- of the last-end system 13 is the total negative terminal of the series energy storage system, and the intermediate system is all the energy storage subsystems between the first-end system 11 and the last-end system 13.

[0043] By controlling the on / off timing of multiple switching units of all insulation detection modules 10 according to the preset timing control logic, the voltage sampling value of its voltage divider module 102 in different on / off timing corresponding detection modes is obtained by the data sampling module of the insulation detection module 10 corresponding to the first-end system 11. The signal processing module 20 calculates the insulation impedance value of the total positive terminal and the total negative terminal of the entire series energy storage system to the casing based on the voltage sampling value.

[0044] Furthermore, with Figure 3 The circuit principle is the same. The detection mode switching module 101 includes a first switching unit 1011, a second switching unit 1012, and a third switching unit 1013. Each switching unit includes a relay. The voltage input terminal of the first relay in the first switching unit 1011 is connected to the positive terminal B+ of the energy storage subsystem. The voltage output terminal of the second relay in the second switching unit 1012 is connected to the negative terminal B- of the energy storage subsystem. The third relay in the third switching unit 1013 is connected to the chassis grounding point EGND of the energy storage subsystem, which can form a voltage divider circuit and a reference potential connection with the chassis ground, ensuring the potential reference stability of the detection signal. To avoid signal interference caused by mechanical relay contact bounce and improve the reliability and response speed of the high-voltage circuit switching, it is preferable that the first, second, and third relays are all solid-state relays.

[0045] Specifically, the voltage divider module 102 in this embodiment includes a first resistor R1, a second resistor R2, a third resistor R3, and a fourth resistor R4. One end of the first resistor R1 is connected to the voltage output terminal of the first relay to receive the positive high-voltage signal output by the first relay, thereby achieving initial voltage division and current limiting to prevent excessively high voltage from directly impacting subsequent modules. The other end of the first resistor R1 is connected to the second resistor R2, forming a voltage divider branch, and is also connected to the input terminal of the data sampling module 103. The other end of the second resistor R2 is connected to the common connection point of the third resistor R3, the voltage input terminal of the third relay, and the ground terminal (GND1) of the data sampling module 103. The other end of the third resistor R3 is connected to the voltage input terminal of the second relay. One end of the fourth resistor R4 is connected to the ground terminal of the data sampling module 103, and the other end is connected to the voltage output terminal of the second relay.

[0046] Furthermore, each switching unit includes a driving unit. The input terminal of the first driving unit in the first switching unit 1011 receives a first control signal CTR B+, and the control output terminal of the first driving unit is connected to the control terminal of the first relay. The input terminal of the second driving unit in the second switching unit 1012 receives a second control signal CTR B-, and the control output terminal of the second driving unit is connected to the control terminal of the second relay. The third driving unit in the third switching unit 1013 receives a third control signal CTR E, and the control output terminal of the third driving unit is connected to the control terminal of the third relay.

[0047] In this embodiment, the first driving unit includes a first NMOS transistor Q1, a fifth resistor R5, and a sixth resistor R6. One end of the fifth resistor R5 receives the first control signal CTR B+, and the other end is connected to the gate of the first NMOS transistor Q1 and one end of the sixth resistor R6. The other end of the sixth resistor R6 is connected to the source of the first NMOS transistor Q1 and grounded. The drain of the first NMOS transistor Q1 is connected to the control terminal of the first relay.

[0048] Further, in this embodiment, the second driving unit includes a second NMOS transistor Q2, a seventh resistor R7, and an eighth resistor R8. One end of the seventh resistor R7 receives the second control signal CTR B-, and the other end is connected to the gate of the second NMOS transistor Q2 and one end of the eighth resistor R8. The other end of the eighth resistor R8 is connected to the source of the second NMOS transistor Q2 and grounded. The drain of the second NMOS transistor Q2 is connected to the control terminal of the second relay.

[0049] Further, in this embodiment, the third driving unit includes a third NMOS transistor Q3, a ninth resistor R9, and a tenth resistor R10. One end of the ninth resistor R9 receives the third control signal CTRE, and the other end is connected to the gate of the third NMOS transistor Q3 and one end of the tenth resistor R10. The other end of the tenth resistor R10 is connected to the source of the third NMOS transistor Q3 and grounded. The drain of the third NMOS transistor Q3 is connected to the control terminal of the third relay.

[0050] At the technical implementation level, the data sampling module 103 is an isolation amplifier, which is enabled and driven by a timing control signal. According to the specific requirements of the insulation detection task (such as single-system steady-state detection, multi-system series dynamic detection), a periodic level signal matching the requirements is applied to its enable terminal to achieve precise control of the module sampling period and ensure that the voltage sampling timing is coordinated with the switching unit on / off logic.

[0051] Furthermore, the configuration selection for the signal processing module 20 can be divided into two categories: one is a built-in main control unit integrated into a series energy storage system, and the other is an independently deployed external independent control chip. The selection scope of this module should at least include hardware carriers such as industrial-grade programmable logic controllers (PLCs) and embedded microcomputer processors. Such carriers need to have signal processing, logic control and instruction output capabilities to meet the core functional requirements of insulation impedance calculation, switching unit control signal generation and detection result determination.

[0052] In addition, such as Figure 5 As shown, the present invention also provides a detection method applied to the insulation detection device, comprising: The first set of timing control signals is sent to each energy storage subsystem via the CAN bus to control the switching units of all energy storage subsystems to close according to a predetermined logic. This causes the voltage divider modules 102 of all energy storage subsystems to be connected in parallel between the total positive terminal of the series energy storage system and the common chassis ground terminal through the closed switches. The voltage of the voltage divider module 102 in the front-end system 11 is collected and recorded as the first detection voltage. The second set of timing control signals is sent to each energy storage subsystem via the CAN bus to control the switching units of all energy storage subsystems to close according to a predetermined logic. This causes the voltage divider modules 102 of all energy storage subsystems to be connected in parallel between the total negative terminal of the series energy storage system and the common chassis ground terminal through the closed switches. The voltage of the voltage divider module 102 in the front-end system 11 is collected and recorded as the second detection voltage. Based on the first detection voltage and the second detection voltage, the insulation resistance values ​​of the total positive terminal to the common casing ground terminal and the total negative terminal to the common casing ground terminal of the series energy storage system are calculated. The insulation impedance value obtained by the solution is compared with the preset insulation safety threshold to obtain the insulation performance test results of the series energy storage system.

[0053] Furthermore, before performing insulation monitoring, the location determination step of the subsystem in the series energy storage system must also be performed, as follows: In the series energy storage system, each adjacent subsystem establishes a communication connection through the CAN bus to complete device identity (ID) registration and status self-check. All subsystems are powered on at the same time, and the two are confirmed to be in the test state through interaction, and the timing logic of synchronous switch control is synchronized. The signal processing module 20 issues a position determination timing command to drive all the detection mode switching modules 101 of all subsystems to be turned on, constructing a complete voltage sampling circuit, including: closing the solid-state relay on the positive terminal B+ side, so that the positive terminal B+ of each subsystem is connected to the series main circuit; closing the solid-state relay on the negative terminal B- side, so that the negative terminal B- of each subsystem is connected to the series main circuit; closing the solid-state relay on the ground terminal EGND side, so that the voltage divider module 102 of each subsystem is connected to the common ground terminal; Each subsystem acquires the output voltage of the voltage divider module 102 through its own data sampling module 103. This voltage value reflects the potential state of the subsystem in the series circuit.

[0054] Since the positive terminal B+ of the first subsystem is the total positive terminal of the entire series energy storage system, the complete voltage divider signal of the series circuit can be collected on its voltage divider module 102. The voltage value matches the preset first-end reference voltage range, so the subsystem that outputs a preset non-zero value is determined to be the first-end system 11.

[0055] After identifying the first-end system 11, the relay on the specific grounding side of the first-end system 11 is disconnected, cutting off part of the circuit between the first-end system and the common ground. The output voltage of the data sampling module 103 of the remaining subsystems is then collected again. Since the negative terminal B- of the last subsystem is the total negative terminal of the entire series energy storage system, its potential is consistent with the common EGND. There is no voltage difference in the voltage divider module 102. Therefore, the subsystem corresponding to the zero output value of the isolation amplifier is identified as the last system 13.

[0056] Since the remaining subsystems are located between the first-end system 11 and the last-end system 13, and their potentials are between the total positive and negative terminals of the series energy storage system, the voltage values ​​collected by the voltage divider module 102 are between the specific value at the first end and zero, and change linearly with the series level. Therefore, the subsystems that output non-zero values ​​at the first end and non-zero values ​​at the last end are identified as intermediate system 12.

[0057] Each subsystem stores its own location information for subsequent insulation detection switch control logic adaptation, such as the first-end system 11 controlling the voltage data sampling process and the end system 13 cooperating to adjust the on / off state of the grounding relay.

[0058] Figure 6A circuit diagram of an insulation detection device in a dual-energy storage system series operation scenario is shown. In energy storage system one, the first, second, and third relays of the detection mode switching module 101 are solid-state relays U1, U2, and U3, respectively. In energy storage system two, the first, second, and third relays of the detection mode switching module 101 are solid-state relays U10, U20, and U30, respectively. The negative terminal B- of energy storage system one and the positive terminal B+ of energy storage system two are connected, and the chassis grounding point EGND of both systems is shared.

[0059] The system controls the simultaneous power-on of energy storage system one and energy storage system two via CAN bus. By exchanging basic information such as device ID and hardware status through CAN communication, it is confirmed that both systems are in a normal, ready-to-test state, and the timing logic of the synchronous switch control is activated.

[0060] According to the preset logic, all detection mode switching modules 101 of the two subsystems are turned on: including B+ side relays (such as solid-state relay U1 in system 1 and solid-state relay U10 in system 2), B- side relays (such as solid-state relay U2 in system 1 and solid-state relay U20 in system 2), and ground side relays (such as solid-state relay U3 in system 1 and solid-state relay U30 in system 2), to construct a complete voltage sampling circuit.

[0061] The output voltage signals of the corresponding voltage divider modules 102 are collected by the isolation amplifier U4 in System 1 and the isolation amplifier U40 in System 2. If the isolation amplifier of a certain subsystem outputs a preset non-zero value, the subsystem is determined to be the first-end system in a series connection, and its positive terminal (B+) is the total positive terminal of the entire series energy storage system; if the isolation amplifier of another subsystem outputs a zero value, the subsystem is determined to be the last-end system in a series connection, and its negative terminal (B-) is the total negative terminal of the entire series energy storage system.

[0062] Solid-state relays U1 and U3 in control system 1 and solid-state relay U30 in system 2 are in the ON state. Solid-state relays U2 in system 1 and U10 and U20 in system 2 are closed. The voltage across the voltage divider resistor R2 is collected using isolation amplifier U4 and denoted as [the voltage is then described]. According to Kirchhoff's voltage law, we can obtain: ; Solid-state relays U1 and U3 in control system 1, and solid-state relays U30 and U20 in system 2 are in the ON state. When solid-state relays U2 in system 1 and U10 in system 2 are closed, the voltage across the voltage divider resistor R2 is collected using isolation amplifier U4 and denoted as . According to Kirchhoff's voltage law, we can obtain: ; By combining the two formulas above to construct a system of equations, and then solving the system using the known voltage divider resistors (R1~R4), the insulation resistance can be obtained. and The specific value; the insulation resistance , By comparing the insulation impedance with the safety threshold corresponding to the energy storage system, the compliance of the system's insulation performance can be determined.

[0063] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. An insulation testing device for a multi-energy storage system series scenario, characterized in that, It includes a signal processing module and multiple insulation detection modules. Each insulation detection module is connected to any subsystem in the series energy storage system and includes: a detection mode switching module, a voltage divider module, a data sampling module, a positive terminal, a negative terminal, and a grounding terminal. Wherein, the positive terminal is connected to the positive terminal B+ of the battery pack in the corresponding subsystem, and the negative terminal is connected to the negative terminal B- of the battery pack in the corresponding subsystem; the grounding terminal is connected to the battery pack housing grounding terminal EGND in the corresponding subsystem, and the grounding terminals in all insulation detection modules are connected. The detection mode switching module includes multiple switching units, which are connected to the voltage divider module to form an electrical connection loop. The output terminal of the voltage divider module is connected to the input terminal of the data sampling module, and the output terminal of the data sampling module is connected to the signal processing module. The on / off state of multiple switching units of each insulation detection module is controlled. The voltage value on the voltage divider module is collected by the corresponding data sampling module. The position of the corresponding subsystem in the whole series energy storage system is determined according to the comparison result of the voltage value. The positive terminal of the insulation detection module corresponding to the first subsystem is connected to the total positive terminal of the series energy storage system, and the negative terminal of the insulation detection module corresponding to the last subsystem is connected to the total negative terminal of the series energy storage system. By controlling the on / off timing of multiple switching units of all insulation detection modules according to preset timing control logic, the data sampling module of the insulation detection module corresponding to the first subsystem obtains the voltage sampling value of its voltage divider module in the detection mode corresponding to different on / off timing. The signal processing module calculates the insulation impedance value of the total positive terminal and the total negative terminal of the entire series energy storage system to the casing based on the voltage sampling value.

2. The insulation testing device according to claim 1, characterized in that, The detection mode switching module includes a first switch unit, a second switch unit, and a third switch unit. Each switch unit includes a relay. The voltage input terminal of the first relay in the first switch unit is connected to the positive terminal. The voltage output terminal of the second relay in the second switch unit is connected to the negative terminal. The third relay in the third switch unit is connected to the ground terminal.

3. The insulation testing device according to claim 2, characterized in that, The voltage divider module includes a first resistor, a second resistor, a third resistor, and a fourth resistor. One end of the first resistor is connected to the voltage output terminal of the first relay, and the other end is connected to the second resistor and the input terminal of the data sampling module. The other end of the second resistor is connected to the common connection point of the third resistor, the voltage input terminal of the third relay, and the ground terminal of the data sampling module. The other end of the third resistor is connected to the voltage input terminal of the second relay. One end of the fourth resistor is connected to the ground terminal of the data sampling module, and the other end is connected to the voltage output terminal of the second relay.

4. The insulation testing device according to claim 3, characterized in that, The data sampling module is driven by a timing control signal. According to the detection task requirements, its enable terminal is applied with a corresponding periodic level signal to control its sampling period.

5. The insulation testing device according to claim 2, characterized in that, Each switching unit includes a driving unit. The input terminal of the first driving unit in the first switching unit receives a first control signal, and the control output terminal of the first driving unit is connected to the control terminal of the first relay. The input terminal of the second driving unit in the second switching unit receives a second control signal, and the control output terminal of the second driving unit is connected to the control terminal of the second relay. The third driving unit in the third switching unit receives a third control signal, and the control output terminal of the third driving unit is connected to the control terminal of the third relay.

6. The insulation testing device according to claim 5, characterized in that, The first driving unit includes a first NMOS transistor, a fifth resistor, and a sixth resistor. One end of the fifth resistor receives the first control signal, and the other end is connected to the gate of the first NMOS transistor and one end of the sixth resistor. The other end of the sixth resistor is connected to the source of the first NMOS transistor and grounded. The drain of the first NMOS transistor is connected to the control terminal of the first relay.

7. The insulation testing device according to claim 5, characterized in that, The second driving unit includes a second NMOS transistor, a seventh resistor, and an eighth resistor. One end of the seventh resistor receives the second control signal, and the other end is connected to the gate of the second NMOS transistor and one end of the eighth resistor. The other end of the eighth resistor is connected to the source of the second NMOS transistor and grounded. The drain of the second NMOS transistor is connected to the control terminal of the second relay.

8. The insulation testing device according to claim 5, characterized in that, The third driving unit includes a third NMOS transistor, a ninth resistor, and a tenth resistor. One end of the ninth resistor receives the third control signal, and the other end is connected to the gate of the third NMOS transistor and one end of the tenth resistor. The other end of the tenth resistor is connected to the source of the third NMOS transistor and grounded. The drain of the third NMOS transistor is connected to the control terminal of the third relay.

9. A detection method applied to the insulation testing device as described in any one of claims 1 to 8, characterized in that, include: Send the first set of timing control signals to each energy storage subsystem to control the switching units of all energy storage subsystems to close according to a predetermined logic, so that the voltage divider modules of all energy storage subsystems are connected in parallel between the total positive terminal of the series energy storage system and the common chassis ground terminal through the closed switches, and collect the voltage of the voltage divider module in the first subsystem and record it as the first detection voltage; Send the second set of timing control signals to each energy storage subsystem to control the switching units of all energy storage subsystems to close according to a predetermined logic, so that the voltage divider modules of all energy storage subsystems are connected in parallel to the total negative terminal of the series energy storage system and the common chassis ground terminal through the closed switches, and collect the voltage of the voltage divider module in the first subsystem and record it as the second detection voltage; Based on the first detection voltage and the second detection voltage, the insulation resistance values ​​of the total positive terminal and the total negative terminal of the series energy storage system to the common chassis grounding terminal are calculated. The insulation impedance value obtained by the solution is compared with the preset insulation safety threshold to obtain the insulation performance test results of the series energy storage system.

10. The detection method according to claim 9, characterized in that, It also includes the subsystem location determination step in the series energy storage system, as follows: In the series energy storage system, each adjacent subsystem establishes a communication connection, all subsystems are powered on at the same time, and the two are confirmed to be in a state of waiting for detection through interaction, and the timing logic of synchronous switch control is used. The detection mode switching modules of all subsystems are turned on to construct a complete voltage sampling circuit, including: closing the solid-state relay on the positive terminal B+ side to connect the positive terminal of each subsystem to the series main circuit; closing the solid-state relay on the negative terminal B- side to connect the negative terminal of each subsystem to the series main circuit. Close the solid-state relay on the GND side of the grounding terminal to connect the voltage divider modules of each subsystem to the common ground terminal; Each subsystem acquires the output voltage of the voltage divider module through its own data sampling module. This voltage value reflects the potential state of the subsystem in the series circuit. Subsystems with preset non-zero output values ​​are identified as the first-end system in the series circuit. The relay on the specific grounding side of the first-end system is driven to disconnect, cutting off part of the circuit between the first end and the common ground. The output voltage of the data sampling modules of the remaining subsystems is acquired again. Subsystems with zero output values ​​are identified as the last-end system in the series circuit. The remaining subsystems with output values ​​that are neither the preset non-zero value of the first end nor the zero value of the last end are identified as intermediate systems in the series circuit.

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