Insulation detection method, system and device and storage medium

Abstract

The invention provides an insulation detection method, system and device and a storage medium. The method comprises the steps of obtaining a high-voltage output state of a parallel battery system; in response to the condition that the parallel battery system is in a non-high-voltage output state, starting a time-sharing detection mode: controlling a battery management system of each battery pack to sequentially activate an insulation detection circuit in each battery pack according to a preset time sequence so as to obtain a corresponding independent insulation resistance value; and in response to the parallel battery system being in a high-voltage output state, starting an overall detection mode: controlling a battery management system corresponding to one target battery pack to activate an insulation detection circuit in the target battery pack so as to obtain an overall insulation resistance value of the parallel battery system after parallel connection.

Description

Technical Field

[0001] This application relates to the field of insulation testing technology, specifically to an insulation testing method, system, device, and storage medium. Background Technology

[0002] With the rapid development of new energy technologies, devices such as electric vehicles and energy storage systems typically employ a parallel architecture of multiple independent battery systems to meet the demands for high power and long range. In this parallel architecture, the reliability of insulation testing is crucial for ensuring the safe operation of the system.

[0003] However, existing insulation testing technologies face significant challenges when dealing with multi-parallel battery systems. Especially in systems with multiple independent parallel battery units, when the insulation testing circuits of each system are activated simultaneously, problems such as the parallel paths formed by the insulation resistance of each battery pack, the parallel connection of distributed capacitance to ground, and crosstalk between detection signals lead to a significant decrease in measurement accuracy, making it difficult to accurately assess the insulation status of the system. Summary of the Invention

[0004] This application provides an insulation testing method, an insulation testing system, an electrical device, and a computer-readable storage medium, aiming to improve the technical problem of low measurement accuracy caused by parallel effects and signal crosstalk in insulation testing of multi-parallel battery systems.

[0005] In a first aspect, embodiments of this application provide an insulation detection method, the method comprising: Obtain the high voltage output status of the parallel battery system; In response to the parallel battery system being in a non-high voltage output state, a time-sharing detection mode is activated: the battery management system of each battery pack is controlled to activate the insulation detection circuit in each battery pack in a preset time sequence to obtain the corresponding independent insulation resistance value. In response to the parallel battery system being in a high-voltage output state, the overall detection mode is activated: the battery management system corresponding to one of the target battery packs is controlled to activate the insulation detection circuit in the target battery pack to obtain the overall insulation resistance value of the parallel battery system after parallel connection.

[0006] This application embodiment can physically isolate the detection circuits of each battery pack by using a time-sharing detection mode when the parallel battery system is in a non-high voltage output state, completely avoiding the parallel effect and signal crosstalk caused by shared load, thereby obtaining accurate independent insulation resistance values; while in the high voltage output state, the parallel battery pack is regarded as a whole, and only single-point detection is activated, which simplifies the calculation process and avoids the errors caused by multiple detection circuits working in parallel, thereby realizing high-precision insulation monitoring under all operating conditions.

[0007] In one embodiment, the battery management system controlling each battery pack sequentially activates the insulation detection circuit within each battery pack according to a preset time sequence, including: Select the i-th battery pack as the current detection target, where i is a variable and its initial value is 1; Send an insulation enable command to the battery management system corresponding to the i-th battery pack, and control the battery management systems corresponding to the other battery packs to keep the insulation detection circuit in the off state; The first electrical detection signal is acquired by the insulation detection circuit of the i-th battery pack, and the independent insulation resistance value of the i-th battery pack is calculated based on the first electrical detection signal. Determine if i is equal to the total number of battery packs; if not, set i = i + 1 and return to the selection step; if yes, complete one round of time-sharing detection.

[0008] The embodiments of this application ensure the orderliness and independence of the detection process through strict logical loop control. Through a physical isolation mechanism of one-on-many-off, the internal resistance and distributed capacitance of other battery packs will not be connected to the measurement circuit of the battery pack under test at any time, thereby solving the problems of inaccurate fault source location and underestimation of measurement value under multi-system parallel architecture.

[0009] In one embodiment, controlling the battery management system corresponding to one of the target battery packs to activate the insulation detection circuit within the target battery pack includes: Select one battery pack from the plurality of battery packs as the target battery pack; Send an insulation opening command to the battery management system corresponding to the target battery pack to close the detection switch of the insulation detection circuit in the target battery pack, and control the battery management systems corresponding to other battery packs besides the target battery pack to keep the insulation detection circuit in the closed state; The insulation detection circuit of the target battery pack acquires a second electrical detection signal, and the overall insulation resistance of the parallel battery system is calculated based on the second electrical detection signal.

[0010] This application embodiment utilizes the equipotential characteristics of high-voltage parallel connection and, through strict interlocking control, prevents high-voltage circulating currents and signal superposition caused by multiple insulation detection circuits being connected to the high-voltage bus at the same time, thus ensuring the stability of the sampling voltage. At the same time, it eliminates the need for complex fusion calculations of multi-source measured resistance data, requiring only a single measurement to accurately assess the system safety under the current high-voltage power supply state, significantly improving detection efficiency and real-time performance.

[0011] In one embodiment, the process of executing the overall detection mode further includes: Monitor whether the insulation detection circuit of the target battery pack currently in operation has malfunctioned; In response to the detection of a fault in the insulation detection circuit of the target battery pack, a shutdown command is sent to the battery management system corresponding to the target battery pack; From the remaining battery packs, select one battery pack as the new target battery pack, and control the battery management system corresponding to the new target battery pack to activate its insulation detection circuit to continue measuring the overall insulation resistance value.

[0012] In this embodiment, the hardware feature of multiple detection circuits in a multi-parallel architecture is fully utilized to construct system-level redundancy, achieving a redundancy mechanism for insulation monitoring without increasing the cost of any backup hardware. For example, for aircraft (eVTOL) or high-speed vehicles, if a detection fails, the system can quickly switch to the insulation detection circuit of another battery pack for detection, ensuring uninterrupted high-voltage insulation monitoring and improving overall safety.

[0013] In one embodiment, obtaining the high-voltage output state of the parallel battery system includes: Obtain the open / closed state of the positive main contactor of each battery pack; In response to the fact that the main positive contactors of all the battery packs are in the open state, it is determined that the parallel battery system is in a non-high voltage output state; In response to the main positive contactor of any of the battery packs being closed, the parallel battery system is determined to be in a high-voltage output state.

[0014] In this embodiment, the direct state of the main positive contactor, a key physical device, is used as a criterion to provide the most direct physical state feedback. This ensures that the detection mode (time-sharing / overall) strictly matches the current physical topology and prevents data errors or short-circuit risks caused by incorrectly starting time-sharing detection during electrical paralleling.

[0015] In one embodiment, the insulation detection circuit includes an unbalanced bridge circuit; obtaining the corresponding independent insulation resistance value, or obtaining the overall insulation resistance value of the parallel battery system after parallel connection, includes: Control the on / off combination of the switch matrix inside the corresponding insulation detection circuit, and collect the voltage of the positive terminal of the battery pack to ground and the voltage of the negative terminal of the battery pack to ground under different on / off combinations to obtain voltage data; The corresponding insulation resistance value is calculated based on the collected voltage data.

[0016] The embodiments of this application clarify the structure of the insulation detection circuit. The insulation detection circuit adopts an unbalanced bridge structure, which is simple and low in cost. Combined with the timing control strategy of this application, it effectively overcomes the measurement distortion defect of the unbalanced bridge in the parallel battery system.

[0017] Secondly, embodiments of this application provide an insulation detection system configured in a parallel battery system, the parallel battery system including multiple battery packs connected in parallel; the insulation detection system includes: a central controller, a communication bus, and multiple monitoring units respectively disposed in the corresponding battery packs; each monitoring unit includes a battery management system and an insulation detection circuit; the central controller is communicatively connected to the battery management system of each monitoring unit through the communication bus; The central controller is configured to: acquire the high-voltage output status of the parallel battery system; in response to the parallel battery system being in a non-high-voltage output state, initiate a time-sharing detection mode: control the battery management system of each battery pack to sequentially activate the insulation detection circuit within each battery pack according to a preset time sequence to acquire the corresponding independent insulation resistance value; in response to the parallel battery system being in a high-voltage output state, initiate an overall detection mode: control the battery management system corresponding to one of the target battery packs to activate the insulation detection circuit within the target battery pack to acquire the overall insulation resistance value of the parallel battery system after parallel connection.

[0018] In this embodiment, the system architecture provided fully reuses the existing BMS hardware resources and communication network in electric vehicles or energy storage systems, without the need to add additional dedicated insulation testers or high-voltage switching boxes, which greatly reduces the overall cost and wiring harness complexity.

[0019] In one embodiment, the central controller is further configured to: In the overall detection mode, if the currently activated insulation detection circuit is determined to be faulty, the central controller automatically sends an activation command to the battery management system in another backup battery pack to take over the insulation detection task.

[0020] The embodiments of this application implement fault self-healing and function takeover at the system level, ensuring 24 / 7 online operation of insulation monitoring services.

[0021] Thirdly, embodiments of this application provide an electrical device, including a parallel battery system and an insulation detection system as described in the second aspect; The central controller is configured to perform the steps of the insulation detection method as described in the first aspect.

[0022] The electrical equipment (such as aircraft, electric vehicles, or energy storage power stations) in this application embodiment can achieve comprehensive and high-precision monitoring of the high-voltage insulation status throughout its entire life cycle by applying the above-mentioned insulation detection method, effectively preventing electrical fires and electric shock accidents.

[0023] Fourthly, embodiments of this application provide a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the steps of the method described in the first aspect.

[0024] As can be seen, in one of the solutions provided in this application, the high-voltage output state of the parallel battery system is first obtained; when the parallel battery system is in a non-high-voltage output state, the detection circuits of each battery pack are physically isolated by using a time-sharing detection mode, which completely avoids the parallel effect and signal crosstalk caused by shared load, thereby obtaining accurate independent insulation resistance values; while in the high-voltage output state, the parallel battery pack is regarded as a whole, and only single-point detection is activated, which simplifies the calculation process and avoids the errors caused by the parallel operation of multiple detection circuits, thereby achieving high-precision insulation monitoring. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the system architecture corresponding to an insulation detection method provided in one embodiment of this application; Figure 2 This is a schematic flowchart of an insulation testing method provided in an embodiment of this application; Figure 3 This is a system example diagram of a parallel battery system provided in one embodiment of this application; Figure 4 This is a schematic diagram illustrating the insulation detection principle of an independent battery pack in an insulation detection method provided in an embodiment of this application; Figure 5 This is a schematic diagram illustrating the overall insulation detection principle of a multi-battery pack in an insulation detection method provided in an embodiment of this application; Figure 6 This is another schematic flowchart of an insulation testing method provided in one embodiment of this application. Detailed Implementation

[0026] To make the technical problems, technical solutions, and beneficial effects solved by this application clearer, the following detailed description is provided in conjunction with embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0027] The technical solutions provided in this application are mainly applied to fields with strict requirements for high-voltage electrical safety, including but not limited to electric vertical takeoff and landing aircraft (eVTOL), electric vehicles (EV), hybrid electric vehicles (HEV), and large-scale energy storage systems (ESS). In these application scenarios, a parallel battery system architecture is typically adopted, consisting of multiple independent battery packs connected in parallel. A common arrangement in this parallel battery system is that the negative main contactor (such as a negative relay) is normally closed. This application primarily targets parallel battery system architectures with normally closed negative contactors. In such architectures, even if the positive main contactors (such as positive relays) of each battery module in the parallel battery system are disconnected, their negative terminals remain electrically connected through normally closed contactors. Therefore, this can easily lead to parallel interference or signal interference during insulation testing.

[0028] For example, as an illustrative example, such as Figure 3 As shown, taking three battery packs as an example, the circuit structure is referenced. Figure 3 The main negative relay of the parallel battery system is normally closed, such as... Figure 3 As shown, the system includes three battery packs: Battery Pack 1 includes Battery Module 1 (BAT1), Battery Pack 2 includes Battery Module 2 (BAT2), and Battery Pack 3 includes Battery Module 3 (BAT3). Each battery pack also includes a high-voltage battery module, an insulation detection circuit, and a Battery Management System (BMS). The negative terminals of BAT1 and BAT2 are connected via negative relay 1, and the negative terminals of BAT2 and BAT3 are connected via negative relay 2. The negative terminal of BAT3 is also connected to one end of the electrical load via negative relay 3. Negative relays 1, 2, and 3 are all normally closed. The positive terminals of BAT1 and BAT2 are connected via positive relay 1, and the positive terminals of BAT2 and BAT3 are connected via positive relay 2. The positive terminal of BAT3 is also connected to one end of the electrical load via positive relay 3. It should also be understood that the battery management system typically includes both hardware and software; the battery management system is the core electronic system used to monitor, protect, control, and optimize its corresponding battery pack.

[0029] It can be seen that insulation testing of parallel battery systems suffers from decreased measurement accuracy due to parallel effects and signal crosstalk, and there is a lack of intelligent methods to automatically switch testing strategies based on the battery system state. Therefore, to address these issues, this application provides an adaptive insulation testing scheme primarily applicable to parallel battery systems.

[0030] To better understand the technical solution of this application, the software and hardware collaborative system and its architecture involved in this application will be described in detail first.

[0031] The technical solution of this application constitutes a complete hardware and software collaborative system, whose core components include two major categories: hardware and software.

[0032] The hardware components mainly include: multiple battery modules as the objects under test; the hardware of the central controller as the decision-making core; the hardware of the battery management system (BMS) corresponding to each battery module; and the insulation detection circuit as the detection execution mechanism.

[0033] The software component mainly includes: the control algorithm of the central controller and the control algorithm of the battery management system of each battery pack. The control algorithm of the central controller and the control algorithm of each battery pack BMS work together to realize the key to the adaptive switching processing of this application.

[0034] like Figure 1 As shown, from the perspective of the logical hierarchy of the system architecture, the hardware and software collaborative system in this case includes a decision-making layer, a control layer, an execution layer, and a resource layer, among which: Decision-making layer: Includes a central controller. This central controller intelligently determines whether to enter time-sharing detection mode or overall detection mode based on real-time monitored system status (such as the high-voltage status of the parallel battery system), and issues commands to the control layer. In this application, the high-voltage output status typically refers to the state where the main positive contactor of the parallel battery system is closed, and the battery modules are electrically connected in parallel and ready or in the process of supplying power.

[0035] Control Layer: This layer comprises the Battery Management System (BMS) distributed across multiple independent battery packs. Upon receiving instructions from the central controller, the BMS controls the insulation detection circuits according to different modes to measure the insulation resistance of the battery modules and returns these values ​​to the central controller. Figure 1 In the example, the control layer uses three battery packs for illustration. Figure 1 The image only shows BMS1, BMS2, and BMS3 corresponding to battery pack 1, battery pack 2, and battery pack 3, respectively.

[0036] Execution Layer: This layer includes an insulation detection circuit (e.g., an unbalanced bridge and an internal switching matrix). Upon receiving instructions from the Battery Management System (BMS), it executes specific circuit switching through changes in the circuit switching matrix to detect the insulation resistance of the battery pack. It is worth noting that in this embodiment, the insulation detection circuit refers to a hardware entity used to perform insulation resistance measurement. In a specific physical product, this circuit can be packaged as a standalone insulation detection module or integrated into the BMS motherboard. Regardless of its physical form, as long as it has a circuit structure including a sampling resistor network and switching units, it falls within the definition of an insulation detection circuit in this application. For example, the insulation detection circuit and the battery management system are typically housed together as a monitoring unit within the corresponding battery pack.

[0037] It is worth noting that the insulation detection circuit can be implemented in various ways, and this application does not limit the specific implementation. For example, as a specific example, the insulation detection circuit includes an unbalanced bridge and an internal switching matrix. The specific implementation of this insulation detection circuit will be described in detail in subsequent embodiments, and will not be elaborated here.

[0038] Resource layer: This refers to the battery modules corresponding to multiple battery packs, such as... Figure 1 The aforementioned multiple high-voltage battery modules include battery module 1, battery module 2, and battery module 3. The battery modules are not only the targets of insulation testing but also the energy foundation of the entire electrical equipment's power system.

[0039] Regarding component connectivity, the central controller connects to all battery management systems (BMS) via a communication bus (such as a CAN bus), issues insulation detection commands, and reads insulation resistance values ​​and status. Simultaneously, upon receiving commands from the central controller, the BMS directly controls the insulation detection module; through changes in the switch matrix within the insulation detection module, the BMS reads the measured values ​​of the high-voltage battery module, calculates the insulation resistance value, and returns the insulation resistance value and insulation status to the central controller.

[0040] In the hardware and software co-operation system provided in this application, the central controller, multiple parallel battery packs (at least two sets), and the BMS and independent insulation detection circuit contained within the battery packs are essential components for implementing this solution. As a preferred embodiment, the insulation detection method employs the unbalanced bridge method, which is mature, reliable, and highly accurate. In terms of software algorithms, a signal processing unit based on a specific sampling frequency and complex filtering algorithms is preferably used to further improve signal quality, combat noise interference, and thus optimize the stability and accuracy of the measurement.

[0041] Please refer to Figure 2 This application provides an insulation testing method, including the following steps: S10: Obtain the high voltage output status of the parallel battery system.

[0042] In this step, the central controller needs to perceive the current system operating status in real time. The method for obtaining this status is flexible and varied, and is not specifically limited. For example, the central controller can read the status of the main positive contactor of the parallel battery system or the vehicle power-on command. Accurately obtaining this high-voltage output status is a prerequisite for implementing the adaptive strategy switching in the embodiments of this application, ensuring that the detection logic matches the physical connection status (isolation or parallel connection).

[0043] S20: In response to the parallel battery system being in a non-high voltage output state, start the time-sharing detection mode: control the battery management system of each battery pack to activate the insulation detection circuit in each battery pack in a preset time sequence to obtain the corresponding independent insulation resistance value.

[0044] In this step, when the parallel battery system is in a non-high voltage output state (usually the positive main contactor of the parallel battery system is disconnected, but the negative terminals are grounded), the embodiment of this application adopts a time-sharing detection mode, that is, a time-sharing detection strategy: the central controller controls the battery management system (BMS) of each battery pack to activate the insulation detection circuit in each battery pack in a preset time sequence to obtain the corresponding independent insulation resistance value.

[0045] It is worth noting that in existing technologies, if simultaneous detection is performed, the insulation resistance to ground (R1, R2...) and distributed capacitance to ground (C1, C2...) of each battery pack will be connected in parallel through the common negative terminal. According to the parallel resistance relationship, the measured values ​​will be significantly distorted in this case. This step strictly isolates the detection actions of each battery pack along the time axis, ensuring that only one insulation detection circuit is operating within any given minute time slice.

[0046] S30: In response to the parallel battery system being in a high-voltage output state, the overall detection mode is activated: the battery management system corresponding to one of the target battery packs is controlled to activate the insulation detection circuit in the target battery pack to obtain the overall insulation resistance value of the parallel battery system after parallel connection.

[0047] In this step, once the high voltage is applied to the electrical equipment, the parallel battery system is electrically integrated. The insulation resistance to ground at any point represents the insulation resistance to ground of the entire parallel battery system. At this time, the central controller initiates the overall detection mode, which employs a single-point detection strategy: it controls the battery management system corresponding to one target battery pack to activate the insulation detection circuit within that target battery pack to obtain the overall insulation resistance value of the parallel battery system. In other words, only one representative battery pack is selected to activate its detection function, while the detection functions of all other battery packs are forcibly disabled.

[0048] As can be seen, the embodiments of this application provide an insulation detection method. In the non-high voltage state, this application uses time-division detection to physically disconnect the parallel circuit of insulation resistance and distributed capacitance caused by the common load of multiple battery packs, avoiding the problem of the measured value being less than the true value, and realizing accurate assessment of the insulation status of a single pack. In the high voltage parallel state, single-point detection avoids the waveform superposition and calculation chaos caused by multiple detection sources injecting signals into the system at the same time, thus improving the accuracy of the detection data.

[0049] It is also worth noting that in this embodiment, the entire process forms a dynamic closed loop. After a single detection cycle is completed, the system updates the status information and returns to the monitoring starting point, continuously monitoring changes in system status to seamlessly switch between the two modes, thereby achieving adaptive intelligent insulation monitoring.

[0050] In one embodiment, step S20, namely, the battery management system controlling each battery pack sequentially activates the insulation detection circuit in each battery pack according to a preset time sequence, includes steps S21 to S24: S21: Select the i-th battery pack as the current detection target, where i is a variable and its initial value is 1.

[0051] S22: Send an insulation activation command to the battery management system corresponding to the i-th battery pack, and control the battery management systems corresponding to the remaining battery packs to keep the insulation detection circuit in the off state.

[0052] S23: Acquire the first electrical detection signal through the insulation detection circuit of the i-th battery pack, and calculate the independent insulation resistance value of the i-th battery pack based on the first electrical detection signal.

[0053] S24: Determine whether i is equal to the total number of battery packs; if not, set i = i + 1 and return to the selection step; if yes, complete one round of time-sharing detection.

[0054] In step S21, a basic indexing mechanism for time-sharing polling is established. Regarding the preset time sequence, in the most basic implementation, it can be a linear sequence based on physical address or CANID order (e.g., battery pack 1 -> battery pack 2 -> battery pack 3). As a preferred, non-limiting approach, this sequence can also be a dynamically adjusted priority sequence. For example, the central controller can read the historical health data of each battery pack or the insulation record of the previous cycle. For instance, if the central controller detects that battery pack 3 experienced a transient insulation resistance fluctuation in the previous operating cycle (although no alarm was triggered), then during the initialization phase of this cycle, the controller can prioritize battery pack 3 as the first detection target when variable i=1, in order to identify potential hazards as early as possible. This dynamic scheduling strategy can significantly improve the system's monitoring response speed to high-risk units.

[0055] Step S22 is a crucial step in achieving the physical isolation required for this application. In a parallel battery system architecture with the main negative contactor normally closed, the negative terminals of all battery packs are electrically connected. Without control, the internal resistance and ground capacitance of the insulation detection circuits (e.g., those containing unbalanced bridges) of all battery packs are effectively connected in parallel. The parallel resistance effect causes the measured insulation resistance to be less than the true value, resulting in false alarms. The parallel capacitance effect increases the ground capacitance, leading to a longer time for the bridge to establish a steady state, affecting sampling accuracy. Through the logic of step S22, while the central controller sends an insulation open command to the i-th battery pack, it must ensure that the insulation detection circuits of all other battery packs (j≠i) are in a high blocking open state (i.e., sending an insulation close command or confirming that they are in a closed state). This physically cuts off the interference path of other battery packs to the current insulation measurement circuit, ensuring the electrical purity of the current insulation measurement circuit.

[0056] Step S23 involves the specific signal acquisition and calculation process. Specifically, the first electrical detection signal refers to the positive-to-ground voltage and negative-to-ground voltage of the i-th battery pack, acquired after the insulation detection circuit of the i-th battery pack is closed. Based on these two voltage values ​​and the known internal resistance parameters of the bridge circuit, the BMS can calculate the independent insulation resistance value of the battery pack using Kirchhoff's laws. For example, taking a system containing three battery packs (BAT1, BAT2, BAT3): when i=1, the bridge circuit of BAT1 is closed, and the bridge circuits of BAT2 and BAT3 are open. At this time, the distributed capacitance of BAT2 / 3 is not connected to the circuit, and the resistance value measured by BAT1 fully represents its own insulation condition. It is worth noting that in some implementations, if the insulation resistance value of BAT1 is calculated to be lower than the severe fault threshold in this step, it can be configured to immediately stop mode, that is, stop subsequent polling and directly report the insulation fault of BAT1, and cut off the high voltage power-on process; it can also be configured to mark and continue mode, that is, record the fault position and continue to detect subsequent battery packs in order to obtain the health status of the entire system at once, and the specific configuration is not limited.

[0057] In step S24, an automated closed-loop process is established. Through cyclical judgment, all parallel battery packs can be automatically traversed to ensure that no one is missed. When i equals the total number (e.g., 3) and the last measurement is completed, the pre-power-on self-test phase ends. At this point, if the independent insulation resistance values ​​of all battery packs are normal, the central controller will issue a command to close the main positive contactor, allowing entry into the high-voltage output state.

[0058] In this embodiment, strict logical loop control ensures the orderliness and independence of the detection process. A physical isolation mechanism with one switch on and multiple switches off ensures that at any given time, the internal resistance and distributed capacitance of other battery packs will not be connected to the measurement circuit of the battery pack under test. This solves the problems of inaccurate fault location and underestimation of measured values ​​in multi-system parallel architectures. Furthermore, it enables clear differentiation of which specific battery pack has an insulation fault, overcoming the difficulty of traditional parallel testing where only low overall system insulation is reported without pinpointing the specific faulty pack, greatly reducing the difficulty of subsequent maintenance and troubleshooting.

[0059] In one embodiment, step S30, namely controlling the battery management system corresponding to one of the target battery packs to activate the insulation detection circuit within the target battery pack to obtain the overall insulation resistance value of the parallel battery system, specifically includes steps S31 to S33: S31: Select one battery pack from the plurality of battery packs as the target battery pack.

[0060] S32: Send an insulation opening command to the battery management system corresponding to the target battery pack to close the detection switch of the insulation detection circuit in the target battery pack, and control the battery management systems corresponding to other battery packs besides the target battery pack to keep the insulation detection circuit in the closed state.

[0061] S33: Acquire a second electrical detection signal through the insulation detection circuit of the target battery pack, and calculate the overall insulation resistance value of the parallel battery system based on the second electrical detection signal.

[0062] Step S31 involves the strategy for determining the monitoring anchor point. In a multi-parallel battery system, since the high-voltage buses of all battery packs are interconnected, theoretically any battery pack can be used as a detection point, such as using the system's default battery pack as the target battery pack. As an example, to adapt to different engineering needs, the selection of the target battery pack can adopt the following non-limiting strategy. For example, always specify the battery pack with the smallest address code (e.g., ID=1) or the one defined as Master by the hardware as the target pack. This strategy is simple in logic and has the fastest response speed. Considering that the insulation detection circuit may contain mechanical relays or photorelays, to prevent the hardware of a certain battery pack from aging prematurely due to long-term single operation, the central controller can adopt a rotation mechanism. For example, select BAT1 in the current power-on cycle and BAT2 in the next power-on cycle, or rotate daily. Alternatively, the central controller can monitor the communication quality of each battery management system (BMS) in real time. If a high packet loss rate is found in the CAN bus of BAT1, the more stable BAT2 can be automatically switched as the target pack to ensure reliable transmission of monitoring data.

[0063] In step S32, this step is an interlocking mechanism to ensure measurement accuracy under high-voltage parallel operation. When the system is in high-voltage output mode, all battery packs are connected in parallel. If the insulation detection circuits (including unbalanced circuits) of two battery packs (e.g., BAT1 and BAT2) are closed simultaneously, this is equivalent to connecting two unbalanced bridges in parallel between the high-voltage bus and ground. Since the clocks of each battery management system (BMS) are difficult to synchronize completely, the detection signals injected by BAT1 and BAT2 will experience phase misalignment or waveform superposition, resulting in chaotic sampling voltages that cannot be calculated. In addition, if there are manufacturing tolerances in the internal resistance of the two bridges, a weak circulating current may be formed between the two detection points. Therefore, in this embodiment, the central controller executes a strict master-slave logic with slaves remaining silent. Preferably, when switching target packs, a timing control of disconnecting before turning on is adopted, that is, first confirming that the previous target pack has been turned off, and then sending the opening command of the new target pack, leaving dead time to completely eliminate signal conflicts.

[0064] In step S33, the second electrical detection signal specifically refers to the positive-to-ground voltage and negative-to-ground voltage of the target battery pack acquired by the ADC after the insulation detection circuit of the target battery pack is closed. Since the main positive contactor is closed, the positive terminals of all battery packs converge to the high-voltage bus, and the negative terminals converge to the main negative bus, forming a single electrical node for the entire power battery system. Therefore, the positive-to-ground voltage of BAT1 is physically equal to the positive-to-ground voltage of BAT2, BAT3, and even the entire high-voltage bus. Based on the acquired positive-to-ground and negative-to-ground voltages, combined with the bridge resistance parameters, the Battery Management System (BMS) can directly calculate the insulation resistance value, which is the overall system-level insulation resistance value including all battery packs, high-voltage wiring harnesses, and loads.

[0065] In this embodiment, the equipotential characteristics of high-voltage parallel connection are utilized, and strict interlocking control is used to prevent high-voltage circulating current and signal superposition caused by multiple insulation detection circuits being connected to the high-voltage bus at the same time, thus ensuring the stability of the sampling voltage. At the same time, there is no need to perform complex fusion calculations of multi-source measured resistance data. Only one measurement is needed to accurately assess the system safety under the current high-voltage power supply state, which significantly improves detection efficiency and real-time performance.

[0066] In one embodiment, the process of executing the overall detection mode further includes steps S34 to S36: S34: Monitor whether the insulation detection circuit of the target battery pack currently in operation has malfunctioned.

[0067] S35: In response to detecting a fault in the insulation detection circuit of the target battery pack, a shutdown command is sent to the battery management system corresponding to the target battery pack.

[0068] S36: Select a new battery pack from the remaining battery packs as the new target battery pack, and control the battery management system corresponding to the new target battery pack to activate its insulation detection circuit to continue measuring the overall insulation resistance value.

[0069] Step S34 involves real-time diagnosis of the health status. During the overall detection mode, the central controller can monitor the currently operating target battery pack (e.g., BAT1) through multiple methods. Exemplary methods include, but are not limited to, communication layer monitoring, data layer monitoring, and hardware layer monitoring. Communication layer monitoring refers to the central controller continuously listening to the periodic messages sent by the target battery pack's battery management system (BMS) via the CAN bus. If no heartbeat frame is received within a preset time window (e.g., 100ms or 200ms), or if the CRC check of the message fails consecutively, the node is considered to have lost communication. Data layer monitoring refers to the central controller performing logical verification on the reported insulation resistance value. If the reported value instantly jumps to a predefined invalid value, or if the voltage sampling value remains at 0V for a long time (indicating a possible open circuit in the sampling harness) while the system is operating normally and there is no insulation alarm, it is considered a data anomaly. Hardware layer monitoring refers to the target battery pack's battery management system (BMS) having a self-diagnostic function. When it detects ADC reference source drift, switch matrix jamming, or power supply abnormality, the central controller can confirm the fault by reading the flag code.

[0070] Step S35 is a fault isolation step. For example, once it is confirmed that the detection function of BAT1 has failed, the central controller immediately sends a shutdown command to BAT1. This ensures that the faulty hardware (which may pose a short circuit risk or send incorrect data) is physically disconnected from the measurement loop, preventing it from interfering with the normal operation of subsequent takeover units.

[0071] In step S36, the dynamic takeover process is implemented. This embodiment of the application can maintain a list of available resources. Taking three battery packs as an example, when BAT1 is removed, the central controller selects a new target pack (e.g., BAT2) from the remaining healthy battery packs such as BAT2 and BAT3, according to a preset strategy (e.g., selecting the pack with the highest remaining charge or random selection). Then, an activation command is immediately sent to BAT2. The insulation detection circuit of BAT2 closes, taking over the monitoring task of the entire high-voltage parallel system. The entire switching process can usually be completed quickly, and for upper-level applications (such as vehicle controllers), the update of insulation data is almost seamless.

[0072] As can be seen, this embodiment fully utilizes the hardware characteristics of multiple insulation detection circuits in a multi-parallel battery system architecture, through the aforementioned technical features, to construct a system-level hot backup mechanism. Redundancy in insulation monitoring is achieved without increasing any backup hardware costs. Especially for aircraft (eVTOL) or high-speed vehicles, if the main detection unit fails, this solution can switch to the backup unit in milliseconds, ensuring uninterrupted high-voltage insulation monitoring and avoiding the risk of system failure due to a single point of failure, thus greatly improving system safety.

[0073] In one embodiment, step S10, namely obtaining the high voltage output state of the parallel battery system, includes steps S11 to S13.

[0074] S11: Obtain the open / closed state of the positive main contactor of each battery pack.

[0075] S12: In response to the fact that the main positive contactors of all the battery packs are in the open state, it is determined that the parallel battery system is in a non-high voltage output state.

[0076] S13: In response to the main positive contactor of any of the battery packs being closed, determine that the parallel battery system is in a high-voltage output state.

[0077] Step S11 involves sensing the underlying physical topology of the system. The main positive contactor is a key high-voltage switching device connected in series between the positive terminal of the battery module and the external high-voltage bus. The main positive contactor is the valve that determines whether the battery pack's energy is output externally. The main positive contactor can be in the form of a relay, for example, such as... Figure 3 This includes positive relay 1, positive relay 2, and positive relay 3. The central controller periodically reads the status messages reported by the BMS of each battery pack via a communication bus (such as a CAN bus). This message contains the status bits of the contactors, for example, 0 represents open and 1 represents closed.

[0078] In step S12, this step defines the trigger boundaries of the time-division detection mode. For example, with... Figure 3 For example, the positive terminals of each battery pack are physically isolated only when all the positive relays of BAT1, BAT2, BAT3, etc., are disconnected. At this time, although the negative terminals are connected together due to the common negative architecture, there is no electrical path between the positive terminals. Only in this state of positive terminal disconnection can the time-sharing detection mode in step S20 be safely executed. If the detection circuits of each pack are forcibly closed in turn when the positive terminals are connected (in parallel), although values ​​can be measured, the measured value is the total resistance value after parallel connection, which cannot reflect the characteristics of a single pack and is prone to causing logical confusion.

[0079] Step S13 defines the triggering conditions for the overall detection mode. As long as the main positive contactor of any battery pack (e.g., BAT1) closes, the external high-voltage bus is energized. If BAT2 also closes, BAT1 and BAT2 are connected in parallel. In this state, it is essential to immediately switch to the overall detection mode. Attempting to disconnect the detection circuits of other packs to test a single pack at this time will result in inaccurate measurements due to the parallel effect, and may also cause the high-voltage bus to impact the detection circuit due to timing issues.

[0080] It should be noted that in some implementations, in actual engineering applications, the contactor may experience contact sticking faults, i.e., the BMS commands it to open, but the physical contacts are stuck in the closed position due to arcing. To prevent misjudging a non-high-voltage state and activating the time-sharing detection mode in such a dangerous situation (which may lead to short circuits or equipment damage), this embodiment also provides a preferred error prevention strategy: the central controller not only reads the feedback from the battery management system (BMS), but also combines it with other control units of the electrical equipment to confirm whether it is a high-voltage output state. For example, taking a vehicle as an example, it can also combine the global status commands from the vehicle controller (VCU) or the charging pile for confirmation. If the VCU has issued a high-voltage command, or detected that the bus voltage is close to the battery voltage, even if a BMS feedback contactor is open, the system should conservatively determine that the current non-high-voltage output state is not met, thereby prohibiting the activation of time-sharing detection and triggering the contact sticking fault troubleshooting process. The above uses a vehicle as an example; similarly, if it is an aircraft, it can be confirmed by the aircraft's main control unit, and the specific method is not limited.

[0081] As can be seen, in this embodiment, by using the above-mentioned technical features, the state of the key physical device, the main positive contactor (relay), is directly used as the criterion to ensure that the detection mode (time-sharing / overall) strictly matches the current physical topology, preventing data errors or short circuit risks caused by incorrectly starting time-sharing detection during electrical parallel connection.

[0082] In one embodiment, the insulation detection circuit includes an unbalanced bridge circuit; obtaining the corresponding independent insulation resistance value, or obtaining the overall insulation resistance value of the parallel battery system after parallel connection, includes: The switching combination of the internal switch matrix of the corresponding insulation detection circuit is controlled, and the voltage of the positive terminal of the battery pack to ground and the voltage of the negative terminal of the battery pack to ground are collected under different switching combinations to obtain voltage data; the corresponding insulation resistance value is calculated based on the collected voltage data.

[0083] In this example, the core of the insulation detection circuit includes an unbalanced bridge and an internal switch matrix. The unbalanced bridge typically consists of a set of precise voltage-dividing resistors (e.g., R0). bridge It is composed of multiple controllable switching devices (such as high-voltage optocoupler relays or MOSFETs), which are located on the connection path between the sampling resistor and the positive terminal (HV+) of the battery pack, the negative terminal (HV-) of the battery pack, and ground (GND).

[0084] In this embodiment, the Battery Management System (BMS) controls the on / off combinations of the corresponding insulation detection circuit and voltage acquisition. Specifically, the BMS constructs different measurement loops on the time axis by controlling the on / off states of the switch matrix. For example, as an illustrative example, a complete measurement cycle typically includes the following stages: Phase 1 (Positive Bias): The BMS closes the positive branch switch and opens the negative branch switch. At this time, the high-voltage positive terminal forms a loop to ground through the sampling resistor. The ADC acquires the positive-to-ground voltage U. p1 and negative terminal to ground voltage U n1 .

[0085] Phase Two (Negative Bias): The BMS disconnects the positive branch switch and closes the negative branch switch. At this time, the high-voltage negative terminal forms a loop to ground through the sampling resistor. The ADC acquires the positive terminal-to-ground voltage U. p2 and negative terminal to ground voltage U n2 .

[0086] Phase 3 (Physical Isolation): When the battery pack is not in a detection time slot (time-sharing detection mode) or is not a target pack (overall detection mode), the BMS controls all switches to disconnect. At this time, the circuit presents a high impedance state to ground, completely cutting off the connection of internal resistance and distributed capacitance.

[0087] The BMS internal processor uses the collected voltage data (U) p1 U n1 U p2 U n2 ), combined with the known bridge resistance parameters (R) bridge Given the reference voltage and Kirchhoff's circuit laws, a system of two linear equations in two variables is established. By solving this system of equations, the current insulation resistance to ground (Rp) and the insulation resistance to ground (Rn) can be calculated simultaneously.

[0088] For example, with Figure 4 For example, Figure 4 This diagram illustrates the insulation testing principle of a single battery pack. Figure 4 It is the basic circuit model for insulation detection, and can be regarded as Figure 3 A simplified form of single-package operation or equivalent.

[0089] BAT represents a battery pack. + and - indicate the positive and negative terminals of the battery.

[0090] Insulation resistance (virtual / object under test): Insulation resistance Rp to ground and insulation resistance Rn to ground. GND indicates the grounding terminal.

[0091] Insulation detection circuit (detection bridge arm): R1≈1MΩ is the sampling standard resistor on the positive side, with a resistance of approximately 1 megohm. R2≈1MΩ is the sampling standard resistor on the negative side, with a resistance of approximately 1 megohm. Kp represents the switch connected to control resistor R1. Kn represents the switch connected to control resistor R2. Vp represents the voltage node of the positive detection branch. Vn represents the voltage node of the negative detection branch.

[0092] For example, Figure 5 This diagram illustrates the insulation detection principle of multiple battery packs connected in parallel. Figure 5 The system architecture is described, which involves three battery packs connected in parallel to a high-voltage bus and equipped with insulation detection circuitry.

[0093] BAT1, BAT2, and BAT3 represent three independent DC high-voltage battery packs, each with a positive (+) and a negative (-) terminal marking.

[0094] Positive relays 1, 2, and 3 control whether the positive terminals of BAT1, BAT2, and BAT3 are connected to the system's main positive bus, respectively. Negative relays 1, 2, and 3 control whether the negative terminals of BAT1, BAT2, and BAT3 are connected to the system's main negative bus, respectively. By closing and opening these relays, the system can be controlled to operate as a single package or in parallel with multiple packages.

[0095] Rp represents the insulation resistance of the system's positive terminal to ground. This is the object being measured, not the physically installed resistance. Rn represents the insulation resistance of the system's negative terminal to ground. It is also the object being measured.

[0096] Insulation detection circuit (unbalanced bridge): R1≈1MΩ: Sampling resistor connected to the main positive bus, with a resistance of approximately 1 megohm. R2≈1MΩ: Sampling resistor connected to the main negative bus, with a resistance of approximately 1 megohm.

[0097] Kp: Positive sampling switch. When closed, resistor R1 is connected to the detection circuit.

[0098] Kn: Negative sampling switch. When closed, resistor R2 is connected to the detection circuit.

[0099] Vp: Voltage node identifier of the positive branch, usually referring to the branch potential where switch Kp is located.

[0100] Vn: Voltage node identifier of the negative branch, usually referring to the branch potential where switch Kn is located.

[0101] Figure 4 and Figure 5 Both of these figures are schematic diagrams of the insulation detection circuit (unbalanced bridge method). Figure 5The demonstration shows the architecture in a scenario where multiple battery packs are connected in parallel. Figure 4 This demonstrates the insulation testing principle for a single battery pack (or a simplified version). Figure 4 or Figure 5 In this process, by controlling different on / off combinations of switches Kp and Kn (e.g., closing only Kp, closing only Kn, or closing them in sequence), the voltage values ​​after voltage division by R1 and R2 are measured. By using Kirchhoff's laws to derive a system of equations, the values ​​of the unknown insulation resistances Rp and Rn can be calculated.

[0102] It is worth noting that in some embodiments, high-frequency switching operations can generate severe ripple interference on the high-voltage bus in actual operating conditions, leading to fluctuations in the sampled voltage. To address the signal interference problem, a preferred implementation is to have the BMS analyze the bus voltage fluctuation frequency in real time and dynamically adjust the ADC sampling frequency to avoid the harmonics of the interference frequency or synchronize it with the interference frequency to reduce aliasing errors. Alternatively, before performing resistance calculations, a digital filtering algorithm (such as moving average filtering or Kalman filtering) can be applied to the original voltage sampling sequence. This effectively removes high-frequency noise and extracts a stable DC voltage component, thereby resolving the measurement fluctuation problem caused by the charging and discharging of the distributed capacitance to ground.

[0103] It is also worth noting that the unbalanced bridge method used in the insulation detection circuit is only one implementation method in this application embodiment. In addition, there may be other implementation methods, and this application does not limit the specific implementation method.

[0104] As can be seen, in this embodiment, through the aforementioned hardware architecture and control logic, the unbalanced bridge structure is simple, requires no expensive isolation transformers and signal generators, and has extremely low cost. Combined with the control strategy of this application, the inherent defect of this circuit structure being susceptible to interference in parallel systems is successfully overcome. Furthermore, by introducing adaptive sampling frequency and digital filtering, electromagnetic interference is effectively resisted, ensuring the accuracy and stability of insulation resistance calculation under complex operating conditions.

[0105] In one embodiment, such as Figure 6 As shown in the embodiments of this application, an insulation detection method is also provided, including the following steps: S1, Begin.

[0106] The power system enters the operation process and initiates the insulation testing process.

[0107] S2, Central controller initialization.

[0108] The central controller completes the initialization process, including system parameter initialization and communication initialization with the battery management system (BMS).

[0109] S3. Detect the parallel battery system to determine if the system is under high voltage.

[0110] The central controller acquires the high-voltage output status of the parallel battery system, which means it detects the parallel battery system to determine whether the current parallel battery system is operating at high voltage.

[0111] S4. Is the system under high pressure? If the system is not connected to high voltage, it will enter time-sharing detection mode; If the system is already under high voltage, it will enter the overall detection mode.

[0112] Among them, the time-sharing detection mode: S5. The central controller sequentially sends insulation opening commands to the BMS.

[0113] When the system is not under high voltage, the central controller sequentially issues insulation opening commands to the battery management system (BMS).

[0114] S6. Independent insulation testing using the unbalanced bridge method.

[0115] The Battery Management System (BMS) performs independent insulation detection on battery packs that receive an insulation activation command using an unbalanced bridge method.

[0116] S7. Calculate and analyze the insulation status.

[0117] The battery management system (BMS) calculates the independent insulation test results and analyzes the corresponding insulation status.

[0118] S8. Has an insulation fault been detected? If an insulation fault is detected, proceed to step S9; If no insulation fault is detected, proceed to step S10.

[0119] S9. Report the corresponding independent battery pack insulation fault.

[0120] When an insulation fault is detected, the Battery Management System (BMS) reports the corresponding battery pack insulation fault to the central controller (e.g., if battery pack 1 is detected, the fault of battery pack 1 is reported).

[0121] S10, Update the insulation status of each battery pack.

[0122] The central controller updates the insulation status of each battery pack based on the detection results.

[0123] Overall detection mode: S11. The central control system issues an insulation opening command to the default BMS.

[0124] With the system already under high voltage, the central control system issues an insulation activation command to the default battery management system (BMS).

[0125] S12. Overall insulation testing using the unbalanced bridge method.

[0126] The battery management system BM uses the unbalanced bridge method to perform insulation testing on the entire system.

[0127] S13. Calculate and analyze the insulation status.

[0128] The battery management system (BM) calculates the overall insulation test results and analyzes the overall insulation status of the system.

[0129] S14. Was an insulation fault detected? If an insulation fault is detected, proceed to step S15; If no insulation fault is detected, proceed to step S16.

[0130] S15. Report system-wide insulation fault.

[0131] When an insulation fault is detected, the Battery Management System (BMS) reports the overall insulation fault to the central control system.

[0132] S16. Update the overall insulation status of the system.

[0133] The central controller updates the overall insulation status of the system based on the detection results.

[0134] S17. Wait for the next insulation test.

[0135] After completing the current insulation test, the system enters a waiting state, awaiting the next insulation test.

[0136] It should be noted that this embodiment describes the processing procedure of one of the adaptive insulation detection methods of this application from a more complete perspective. For more implementation details and alternative implementation methods, please refer to the description of the relevant embodiments above, which will not be repeated here.

[0137] In this embodiment, the entire process forms a dynamic closed loop. After a single detection cycle is completed, the system updates the status information and returns to the monitoring starting point, continuously monitoring changes in system status to seamlessly switch between the two modes, thereby achieving adaptive intelligent insulation monitoring.

[0138] This application embodiment also provides an insulation detection system configured in a parallel battery system, the parallel battery system including multiple battery packs connected in parallel; the insulation detection system includes: a central controller, a communication bus, and multiple monitoring units respectively disposed in the corresponding battery packs; each monitoring unit includes a battery management system and an insulation detection circuit; the central controller is communicatively connected to the battery management system of each monitoring unit through the communication bus.

[0139] The central controller is configured to: acquire the high-voltage output status of the parallel battery system; in response to the parallel battery system being in a non-high-voltage output state, initiate a time-sharing detection mode: control the battery management system of each battery pack to sequentially activate the insulation detection circuit within each battery pack according to a preset time sequence to acquire the corresponding independent insulation resistance value; in response to the parallel battery system being in a high-voltage output state, initiate an overall detection mode: control the battery management system corresponding to one of the target battery packs to activate the insulation detection circuit within the target battery pack to acquire the overall insulation resistance value of the parallel battery system after parallel connection.

[0140] In one embodiment, the central controller is further configured to: in the overall detection mode, if it is determined that the currently activated insulation detection circuit has failed, the central controller automatically sends an activation command to the battery management system in another backup battery pack to take over the insulation detection task.

[0141] As can be seen, this embodiment fully reuses the existing BMS hardware resources and CAN communication network in electrical equipment such as aircraft or energy storage systems, without the need to add additional dedicated insulation testers or high-voltage switching boxes, which greatly reduces the overall cost and wiring harness complexity.

[0142] It should be noted that for details regarding an insulation detection system, please refer to the descriptions in the foregoing method embodiments. To avoid redundancy, these descriptions will not be repeated here.

[0143] In one embodiment, this application provides an electrical device including a parallel battery system and an insulation detection system; the insulation detection system includes: a central controller, a communication bus, and multiple monitoring units respectively disposed within corresponding battery packs; each monitoring unit includes a battery management system and an insulation detection circuit; the central controller is communicatively connected to the battery management system of each monitoring unit through the communication bus; The central controller is configured to perform the steps of the insulation detection method as described in any of the foregoing embodiments.

[0144] In this embodiment, the electrical equipment includes, but is not limited to: Aerospace equipment: such as electric vertical takeoff and landing aircraft (eVTOL) and electric aircraft.

[0145] New energy vehicles: battery electric vehicles (BEV), hybrid electric vehicles (HEV / PHEV), and fuel cell electric vehicles (FCEV).

[0146] Energy storage equipment: containerized large-scale energy storage power stations (ESS), residential energy storage systems, and mobile charging vehicles.

[0147] These devices share a common feature: they all employ a multi-battery pack parallel architecture to meet high power or high capacity requirements.

[0148] In this electrical equipment, the hardware components of the insulation detection system are integrated in the following way: Central controller: For example, it is specifically implemented as a master battery management unit (Master BMS). As the decision-making core, it is usually an embedded control box containing a high-performance MCU.

[0149] Communication bus: The central controller sends relevant instructions to each battery pack and receives insulation resistance data through this bus.

[0150] Monitoring Unit: Physically integrated inside each battery pack. The insulation detection circuitry is typically soldered directly onto the PCB motherboard of the slave BMS as an onboard functional module.

[0151] The central controller is configured to execute the methods mentioned in the foregoing embodiments, enabling the electrical equipment to possess full lifecycle security protection capabilities. Alternatively, the electrical equipment includes the hardware and software collaborative architecture system described in the foregoing embodiments. Further details can be found in the relevant descriptions of the foregoing embodiments, and will not be repeated here.

[0152] The electrical equipment described in this application embodiment does not require the installation of an expensive and bulky independent insulation tester. It can achieve high-precision insulation safety management by utilizing existing BMS hardware resources in conjunction with the control algorithm of this application, which significantly reduces the overall BOM cost and wiring harness weight, while improving the availability and safety of the system.

[0153] In this application, "multiple" refers to two or more.

[0154] In this application, unless otherwise expressly defined, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection between two components. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0155] The terms “first,” “second,” “third,” “fourth,” etc., in this application (if present) are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence.

[0156] In this application, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent three cases: A existing alone, A and B existing simultaneously, and B existing alone. Additionally, in this application, the character " / " generally indicates that the preceding and following related objects have an "or" relationship.

[0157] Unless otherwise specified, all steps in this application may be performed sequentially or randomly. For example, if the method includes steps A and B, it means that the method may include steps A and B performed sequentially, or it may include steps B and A performed sequentially. For example, if the method may also include step C, it means that step C may be added to the method in any order. For example, the method may include steps A, B, and C, or it may include steps A, C, and B, or it may include steps C, A, and B, etc.

[0158] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. An insulation testing method, characterized in that, The method includes: Obtain the high voltage output status of the parallel battery system; In response to the parallel battery system being in a non-high voltage output state, a time-sharing detection mode is activated: the battery management system of each battery pack is controlled to activate the insulation detection circuit in each battery pack in a preset time sequence to obtain the corresponding independent insulation resistance value. In response to the parallel battery system being in a high-voltage output state, the overall detection mode is activated: the battery management system corresponding to one of the target battery packs is controlled to activate the insulation detection circuit in the target battery pack to obtain the overall insulation resistance value of the parallel battery system after parallel connection.

2. The method according to claim 1, characterized in that, The battery management system controlling each battery pack sequentially activates the insulation detection circuit within each battery pack according to a preset time sequence, including: Select the i-th battery pack as the current detection target, where i is a variable and its initial value is 1; Send an insulation enable command to the battery management system corresponding to the i-th battery pack, and control the battery management systems corresponding to the other battery packs to keep the insulation detection circuit in the off state; The first electrical detection signal is acquired by the insulation detection circuit of the i-th battery pack, and the independent insulation resistance value of the i-th battery pack is calculated based on the first electrical detection signal. Determine if i is equal to the total number of battery packs; if not, set i = i + 1 and return to the selection step; if yes, complete one round of time-sharing detection.

3. The insulation testing method according to claim 1, characterized in that, The step of controlling the battery management system corresponding to one of the target battery packs to activate the insulation detection circuit within the target battery pack includes: Select one battery pack from the plurality of battery packs as the target battery pack; Send an insulation opening command to the battery management system corresponding to the target battery pack to close the detection switch of the insulation detection circuit in the target battery pack, and control the battery management systems corresponding to other battery packs besides the target battery pack to keep the insulation detection circuit in the closed state; The insulation detection circuit of the target battery pack acquires a second electrical detection signal, and the overall insulation resistance of the parallel battery system is calculated based on the second electrical detection signal.

4. The method according to claim 1, characterized in that, The process of executing the overall detection mode also includes: Monitor whether the insulation detection circuit of the target battery pack currently in operation has malfunctioned; In response to the detection of a fault in the insulation detection circuit of the target battery pack, a shutdown command is sent to the battery management system corresponding to the target battery pack; From the remaining battery packs, select one battery pack as the new target battery pack, and control the battery management system corresponding to the new target battery pack to activate its insulation detection circuit to continue measuring the overall insulation resistance value.

5. The method according to claim 1, characterized in that, The step of obtaining the high-voltage output state of the parallel battery system includes: Obtain the open / closed state of the positive main contactor of each battery pack; In response to the fact that the main positive contactors of all the battery packs are in the open state, it is determined that the parallel battery system is in a non-high voltage output state; In response to the main positive contactor of any of the battery packs being closed, the parallel battery system is determined to be in a high-voltage output state.

6. The method according to claim 1, characterized in that, The insulation detection circuit includes an unbalanced bridge circuit; obtaining the corresponding independent insulation resistance value, or obtaining the overall insulation resistance value of the parallel battery system after parallel connection, includes: Control the on / off combination of the switch matrix inside the corresponding insulation detection circuit, and collect the voltage of the positive terminal of the battery pack to ground and the voltage of the negative terminal of the battery pack to ground under different on / off combinations to obtain voltage data; The corresponding insulation resistance value is calculated based on the collected voltage data.

7. An insulation detection system, characterized in that, The insulation detection system is configured in a parallel battery system, which includes multiple battery packs connected in parallel. The insulation detection system includes a central controller, a communication bus, and multiple monitoring units respectively disposed within the corresponding battery packs. Each monitoring unit includes a battery management system and an insulation detection circuit. The central controller is communicatively connected to the battery management system of each monitoring unit through the communication bus. The central controller is configured to: acquire the high-voltage output status of the parallel battery system; in response to the parallel battery system being in a non-high-voltage output state, initiate a time-sharing detection mode: control the battery management system of each battery pack to sequentially activate the insulation detection circuit within each battery pack according to a preset time sequence to acquire the corresponding independent insulation resistance value; in response to the parallel battery system being in a high-voltage output state, initiate an overall detection mode: control the battery management system corresponding to one of the target battery packs to activate the insulation detection circuit within the target battery pack to acquire the overall insulation resistance value of the parallel battery system after parallel connection.

8. The insulation detection system according to claim 7, characterized in that, The central controller is also configured to: In the overall detection mode, if the currently activated insulation detection circuit is determined to be faulty, the central controller automatically sends an activation command to the battery management system in another backup battery pack to take over the insulation detection task.

9. An electrical appliance, characterized in that, The system includes a parallel battery system and an insulation detection system. The insulation detection system includes a central controller, a communication bus, and multiple monitoring units respectively disposed within the corresponding battery packs. Each monitoring unit includes a battery management system and an insulation detection circuit. The central controller is communicatively connected to the battery management system of each monitoring unit through the communication bus. The central controller is configured to perform the steps of the insulation detection method as described in any one of claims 1 to 6.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by a processor, it implements the steps of the method according to any one of claims 1 to 6.

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