Power battery relay adhesion state detection method, system, equipment and medium

Abstract

The invention relates to the technical field of new energy automobile power battery management, in particular to a power battery relay adhesion state detection method, system and device and a medium. Controlling the first isolating switch and the second isolating switch to be switched on, and controlling the main positive relay, the pre-charging relay and the main negative relay to be switched off; measuring a first voltage value of a connection point between the first isolation switch and the second divider resistor through a first acquisition circuit; measuring a second voltage value of a connection point between the second isolation switch and the fourth divider resistor through a second acquisition circuit; and judging the adhesion state of the main positive relay or the pre-charging relay according to the ratio of the first voltage value to the second voltage value. A double-circuit high-voltage acquisition loop design is adopted, and effective detection of a low-side main negative relay is realized through a functional connection module. Through ingenious circuit design and unified detection logic, the states of all relays can be accurately detected only by using two acquisition loops, the circuit structure is obviously simplified, the cost is reduced, and the detection reliability and real-time performance are improved.

Description

Technical Field

[0001] This invention relates to the field of power battery management technology for new energy vehicles, and in particular to a method, system, device and medium for detecting the sticking state of a power battery relay. Background Technology

[0002] With the rapid development of the new energy vehicle industry, the safety and reliability requirements of power battery management systems are increasing. Relays, as key control components in power battery systems, are responsible for controlling the on / off state of the high-voltage circuit, and their operating status directly affects the safety performance of the entire vehicle. In practical applications, relays may experience sticking faults, meaning the contacts cannot disconnect normally. If this fault is not detected and addressed in a timely manner, it may lead to serious safety accidents.

[0003] Traditional relay status detection methods primarily rely on relays with auxiliary contacts for diagnosis. However, these relays are expensive, and the false alarm rate is high when using auxiliary contacts for diagnosis, making it difficult to meet the needs of large-scale industrial applications. Therefore, most companies choose to use relays without auxiliary contacts, identifying their open or closed state by detecting the voltage across the relay's terminals.

[0004] Existing methods for detecting relay adhesion without auxiliary contacts present numerous technical challenges. For high-end relays, such as main positive relays and pre-charge relays, the front-end voltage is already high, making the detection circuit relatively simple. However, for low-side relays, such as main negative relays, the design of the detection circuit becomes a technical difficulty. The key lies in how to effectively raise or lower the front-end voltage of the relay so as to accurately determine its operating status through a voltage comparison method.

[0005] Current technical solutions typically require designing an independent high-voltage detection circuit for each high-voltage acquisition point, or using a matrix switch for detection, resulting in a large number of detection circuits, complex diagnostic logic, and high system costs. For the detection of low-side relays, existing technologies generally require an additional power supply to detect the low-side circuit voltage, which not only increases the number of circuit components and costs but also complicates the circuit. Another technical solution utilizes a combination of insulation detection circuits and voltage divider circuits, but this is affected by the insulation detection time, making it unsuitable for real-time vehicle power-on, and is also significantly affected by load capacitance, easily generating false alarms; its reliability needs further verification. Summary of the Invention

[0006] To address the problems existing in the prior art, this invention aims to solve the technical problems of complex detection circuits, high costs, cumbersome diagnostic logic, and difficulty in detecting low-side relays in power battery relay status detection. It provides a low-cost, high-reliability, and simple diagnostic logic method for detecting the adhesion status of power battery relays, achieving unified and effective detection of high-side and low-side relays, and improving the overall performance and safety of the system.

[0007] To solve the above-mentioned technical problems, the present invention provides the following technical solution:

[0008] In a first aspect, embodiments of the present invention provide a method for detecting the sticking state of a power battery relay, which includes controlling a first disconnecting switch and a second disconnecting switch to be turned on, and controlling a main positive relay, a precharge relay and a main negative relay to be turned off.

[0009] The first voltage value at the connection point between the first isolation switch and the second voltage divider resistor is measured by the first acquisition circuit.

[0010] The second voltage value at the connection point between the second isolation switch and the fourth voltage divider resistor is measured by the second acquisition circuit.

[0011] The sticking status of the main positive relay or the precharge relay is determined based on the ratio of the first voltage value to the second voltage value.

[0012] As a preferred embodiment of the power battery relay adhesion state detection method of the present invention, the method for determining the adhesion state of the main positive relay or the precharge relay based on the ratio of the first voltage value to the second voltage value includes:

[0013] When the second voltage value is less than 5% of the first voltage value, it is determined that the main positive relay or the precharge relay is disconnected;

[0014] When the second voltage value is greater than 95% of the first voltage value, it is determined that the main positive relay or the precharge relay is stuck.

[0015] As a preferred embodiment of the power battery relay adhesion state detection method of the present invention, it further includes:

[0016] Control the precharge relay to close, while keeping the main positive relay and the main negative relay open;

[0017] The first acquisition module acquires the third voltage value at the connection point between the first isolation module and the second voltage divider circuit, and the second acquisition module acquires the fourth voltage value at the connection point between the second isolation module and the fourth voltage divider circuit.

[0018] The sticking status of the main negative relay is determined based on the ratio of the third voltage value to the fourth voltage value.

[0019] In a preferred embodiment of the power battery relay adhesion state detection method of the present invention, determining the adhesion state of the main negative relay based on the ratio of the third voltage value to the fourth voltage value includes:

[0020] When the fourth voltage value is greater than 95% of the third voltage value, it is determined that the main negative relay is disconnected;

[0021] When the fourth voltage value is less than the preset reference voltage, it is determined that the main negative relay is stuck.

[0022] As a preferred embodiment of the power battery relay adhesion state detection method of the present invention, the first isolation module includes a first optocoupler switch, and the second isolation module includes a second optocoupler switch.

[0023] The first voltage divider circuit includes a first voltage divider resistor, the second voltage divider circuit includes a second voltage divider resistor, the third voltage divider circuit includes a third voltage divider resistor, and the fourth voltage divider circuit includes a fourth voltage divider resistor.

[0024] As a preferred embodiment of the power battery relay adhesion state detection method of the present invention, it further includes a functional connection module, which is connected between the third voltage divider circuit and the main negative relay.

[0025] The functional connection module includes a fifth voltage divider resistor or a third optocoupler switch;

[0026] A diode is also provided between the functional connection module and the main negative relay. The positive terminal of the diode is connected to the functional connection module, and the negative terminal of the diode is connected to the main negative relay.

[0027] As a preferred embodiment of the power battery relay adhesion state detection method of the present invention, wherein: the first voltage divider resistor has a first end connected to the high-side positive terminal of the battery pack, and a second end connected to the second voltage divider resistor through a first optocoupler switch;

[0028] The third voltage divider resistor has its first end connected to the second end of the main positive relay or precharge relay, and its second end connected to the fourth voltage divider resistor through the second optocoupler switch.

[0029] The first acquisition circuit is connected between the first optocoupler switch and the second voltage divider resistor;

[0030] The second acquisition circuit is connected between the second optocoupler switch and the fourth voltage divider resistor.

[0031] Secondly, embodiments of the present invention provide a power battery relay adhesion state detection system, which includes a control module for controlling the first isolation module and the second isolation module to be turned on, and simultaneously controlling the main positive relay, the precharge relay and the main negative relay to be turned off.

[0032] The voltage acquisition module is used to acquire the first voltage value at the connection point between the first isolation module and the second voltage divider circuit, and the second voltage value at the connection point between the second isolation module and the fourth voltage divider circuit.

[0033] The status judgment module is used to determine the sticking status of the main positive relay or the precharge relay based on the ratio of the first voltage value to the second voltage value.

[0034] Thirdly, embodiments of the present invention provide a computer device, including a memory and a processor, wherein the memory stores a computer program, wherein: when the computer program instructions are executed by the processor, they implement the steps of the power battery relay adhesion state detection method as described in the first aspect of the present invention.

[0035] Fourthly, embodiments of the present invention provide a computer-readable storage medium having a computer program stored thereon, wherein: when the computer program instructions are executed by a processor, they implement the steps of the power battery relay adhesion state detection method as described in the first aspect of the present invention.

[0036] The beneficial effects of this invention are as follows: Through a clever dual-channel high-voltage acquisition circuit design, this invention completely changes the complex architecture of traditional solutions that require an independent detection circuit for each relay. Accurate detection of the status of all relays can be achieved using only two acquisition circuits. The circuit topology is clear and simple, significantly reducing system complexity.

[0037] The innovative design of the functional connection module is the core highlight of this invention. A simple connection module effectively solves the technical challenge of low-side relay detection, avoiding the need for additional power supplies and complex matrix switches required in traditional solutions. The number of components required by the system is significantly reduced, effectively controlling both manufacturing and maintenance costs.

[0038] This invention establishes a unified method for voltage ratio analysis, employing the same detection principle and judgment criteria for both high-side and low-side relays. This uniformity not only simplifies the implementation of software algorithms but also improves the maintainability and scalability of the system.

[0039] Electrical isolation is achieved through optocoupler switches, effectively isolating the high-voltage side from the control circuit and ensuring the safety of the testing process. Simultaneously, the diode protection circuit design effectively prevents surge voltage damage to the testing circuit, resulting in strong system anti-interference capabilities and stable and reliable performance in complex automotive environments.

[0040] This invention eliminates the time dependence of traditional insulation testing methods, allowing for rapid results without waiting for complex insulation testing to complete. This rapid response characteristic is of great significance for vehicle power-on timing control, improving system real-time performance and user experience.

[0041] This invention provides two implementation methods for the functional connection module, each suitable for different isolation requirements and application scenarios. Whether for applications with high electrical isolation requirements or strict cost control, a suitable technical solution can be found.

[0042] By setting reasonable thresholds and employing multiple judgment logics, this invention can accurately distinguish between different states of relays, such as normal disconnection and sticking, effectively avoiding the false alarms and missed alarms common in traditional solutions. The detection results are accurate and reliable, providing a solid guarantee for the safe operation of the power battery system.

[0043] The design of this invention fully considers compatibility with existing battery management systems, making it easy to integrate into various new energy vehicle platforms. The standardized interface design and universal control logic give this technical solution promising prospects for industrial application. Attached Figure Description

[0044] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0045] Figure 1 A flowchart for a method to detect the sticking state of a power battery relay;

[0046] Figure 2 A diagram of a computer device for detecting the sticking state of a power battery relay;

[0047] Figure 3 A schematic diagram of the detection circuit for a method to detect the sticking state of a power battery relay;

[0048] Figure 4 Another schematic diagram of the detection circuit for the power battery relay adhesion state detection method;

[0049] Figure 5 The specific circuit diagram of the detection circuit for the power battery relay adhesion state detection method;

[0050] Figure 6 Another specific circuit diagram of the detection circuit for the power battery relay adhesion detection method. Detailed Implementation

[0051] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0052] Many specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein, and those skilled in the art can make similar extensions without departing from the spirit of the invention. Therefore, the invention is not limited to the specific embodiments disclosed below.

[0053] Secondly, the term "an embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The phrase "in one embodiment" appearing in different places throughout this specification does not necessarily refer to the same embodiment, nor is it a single embodiment or an embodiment selectively excluded from other embodiments.

[0054] Example 1

[0055] Reference Figures 1-2 This is the first embodiment of the present invention, which provides a method for detecting the sticking state of a power battery relay, including:

[0056] S100: Controls the first and second isolating switches to be turned on, and controls the main positive relay, precharge relay and main negative relay to be turned off;

[0057] S200: Measure the first voltage value at the connection point between the first isolation switch and the second voltage divider resistor through the first acquisition circuit;

[0058] S300: Measure the second voltage value at the connection point between the second isolation switch and the fourth voltage divider resistor through the second acquisition circuit;

[0059] S400: Determine the sticking status of the main positive relay or precharge relay based on the ratio of the first voltage value of the power battery relay to the second voltage value of the power battery relay.

[0060] Relay testing in power battery systems faces multiple technical challenges. First, traditional relays with auxiliary contacts are expensive and have a high false alarm rate, making them difficult to meet industrialization requirements. Second, for the testing of relays without auxiliary contacts, the front-end voltage of high-side relays (such as the main positive relay S1 and pre-charge relay S2) is the high-voltage PACK+, making testing relatively simple. However, the design of the detection circuit for low-side relays (main negative relay S3) is a key challenge. Existing technologies typically require an additional power supply to raise or lower the relay's front-end voltage, leading to increased circuit components, higher costs, and more complex circuitry. Furthermore, multi-relay testing in high-voltage systems usually requires designing an independent detection circuit for each high-voltage acquisition point or using a matrix switch, resulting in a large number of detection circuits and complex diagnostic logic. This invention addresses these problems specifically through steps S100-S400: S100 establishes a standard testing environment by controlling the state of the isolating switch; S200-S300 establish a voltage reference through dual-channel voltage acquisition; and S400 achieves accurate adhesion status judgment through voltage ratio analysis.

[0061] Claim 1 constitutes a complete relay sticking detection solution through four core steps. First, by controlling the first and second disconnecting switches to be on while simultaneously controlling all relays to be off, a standardized detection environment is established to ensure that the detection process is not interfered with by the status of other relays. Second, the first voltage value at the connection point between the first disconnecting switch and the second voltage divider resistor is measured by the first acquisition circuit to obtain a reference value for the total voltage of the battery pack. Then, the second voltage value at the connection point between the second disconnecting switch and the fourth voltage divider resistor is measured by the second acquisition circuit to obtain the actual voltage value at the relay's downstream end. Finally, the relay sticking status is determined by analyzing the ratio of the two voltage values. When the ratio is within the normal range, the relay is considered to be normally disconnected; when the ratio is abnormal, the relay is considered to be sticking. The core innovation of this technical solution lies in the design of the functional connection module, which reduces the number of high-voltage acquisition circuits required in traditional solutions, simplifies the detection logic, reduces system costs, and significantly reduces the influence of high-voltage system capacitance through the isolation module, thereby improving the reliability and accuracy of the detection.

[0062] Example 2

[0063] Reference Figures 1-6 This is the second embodiment of the present invention.

[0064] In this embodiment of the application, step S100, which controls the state of the disconnecting switch to establish a detection environment, includes the following steps A1-A3:

[0065] A1: Construct a dual-channel high-voltage acquisition loop system and establish a complete detection circuit topology.

[0066] Specifically, such as Figure 3As shown, this invention employs two high-voltage acquisition circuits (high-voltage acquisition circuit 1 within the dashed box and high-voltage acquisition circuit 3 within the dashed box), a control unit 2, and a functional connection module 4 to form a complete detection system. The first terminal of high-voltage acquisition circuit 1 is connected to the positive terminal PACK+ on the high side of the battery pack, the second terminal is connected to the negative terminal PACK- on the low side of the battery pack, and the third terminal is connected to the control unit 2. It is used to acquire the voltage of PACK+ to ground, obtaining the total voltage U1 of the battery pack. The first terminal of high-voltage acquisition circuit 2 is connected to the second terminal of the main positive relay / pre-charge relay, the second terminal is connected to the first terminal of the main negative relay, and the third terminal is connected to the first terminal of the functional module. It is used to acquire the voltage of LINK+ / LINK-.

[0067] In one alternative implementation, the dual-channel high-voltage acquisition circuit can also be designed using differential acquisition, which improves the common-mode rejection ratio and reduces the impact of environmental interference on measurement accuracy through a differential amplifier.

[0068] It should be noted that the design of the dual-channel high-voltage acquisition circuit is one of the core innovations of this invention. Compared with the traditional solution that requires multiple independent high-voltage detection circuits, this invention achieves the detection of the status of all relays with only two acquisition circuits through ingenious circuit design, which greatly reduces the system complexity and cost.

[0069] A2: Control the first optocoupler switch K1 and the second optocoupler switch K2 to be turned on simultaneously to establish a voltage detection circuit.

[0070] Specifically, such as Figure 5 As shown, the first optocoupler switch K1 controls the on / off state of high-voltage acquisition circuit 1, and the second optocoupler switch K2 controls the on / off state of high-voltage acquisition circuit 2. When the control unit issues a conduction command, both optocouplers close simultaneously, forming a complete detection circuit from PACK+ through the voltage divider network to PACK-. The selection of optocouplers ensures electrical isolation between the high-voltage side and the control circuit, improving system safety.

[0071] In one alternative implementation, the control signal of the optocoupler switch can also be modulated using PWM, and the detection circuit can be precisely controlled by adjusting the duty cycle, thereby further improving the detection accuracy.

[0072] It should be noted that the response time of the optocoupler switch directly affects the detection efficiency. High-speed optocouplers with a response time of less than 1ms are usually selected to meet the requirements of real-time detection.

[0073] A3: Control the main positive relay S1, precharge relay S2 and main negative relay S3 to be in the off state to establish a standard testing environment.

[0074] Specifically, the control unit sends a disconnect command to the control coil of each relay to ensure that all relay contacts are in the open position. For example... Figure 3 As shown, the main positive relay S1 and the precharge relay S2 are connected in parallel between PACK+ and LINK+, while the main negative relay S3 is connected between LINK- and PACK-. This layout design allows for the status determination of relays in different positions using a unified detection method.

[0075] In an alternative implementation, a relay status feedback mechanism can be added to confirm whether the relay is truly disconnected by detecting the relay auxiliary contact or coil current, thereby improving detection reliability.

[0076] It should be noted that establishing a standard testing environment is a crucial step in ensuring testing accuracy. Any accidental closure of a relay may affect the voltage distribution and lead to misjudgment.

[0077] In this embodiment of the application, step S200 involves voltage measurement via the first acquisition circuit, including the following steps B1-B3:

[0078] B1: Determining the sticking status of the main positive relay or precharge relay based on the ratio of the first voltage value to the second voltage value of the power battery relay includes:

[0079] When the second voltage value of the power battery relay is less than 5% of the first voltage value of the power battery relay, it is determined that the main positive relay or the precharge relay of the power battery relay is disconnected.

[0080] When the second voltage value of the power battery relay is greater than 95% of the first voltage value of the power battery relay, it is determined that the main positive relay or the precharge relay of the power battery relay is stuck.

[0081] It should be noted that the first acquisition circuit is connected to the node between the first optocoupler switch K1 and the second voltage divider resistor R2 to measure the voltage value to ground at that point.

[0082] Specifically, such as Figure 5 As shown, the first end of the first voltage divider resistor R1 is connected to the positive terminal PACK+ of the battery pack, and the second end is connected to the second voltage divider resistor R2 through the first optocoupler switch K1. The other end of the second voltage divider resistor R2 is connected to the negative terminal PACK- of the battery pack. The sampling point of the first acquisition circuit is located at the connection node between K1 and R2. According to the voltage divider principle, the voltage value at this point can reflect the total voltage of the battery pack.

[0083] The formula for calculating the voltage divider is: First voltage value = Total voltage of battery pack × R2 / (R1 + R2)

[0084] In one alternative implementation, the first acquisition circuit may further include a filtering circuit and an amplification circuit to improve signal stability and measurement accuracy. The filtering circuit may employ RC filtering or active filtering to remove high-frequency interference signals. To improve measurement accuracy, a high-precision reference voltage source can be used to calibrate the ADC, and a temperature compensation algorithm can be used to correct for the temperature drift effect of the voltage divider resistors.

[0085] It should be noted that the selection of voltage divider resistors needs to consider factors such as power consumption, accuracy, and temperature coefficient. High-precision, low-temperature-drift metal film resistors or precision resistors are typically chosen, and the resistance ratio design should balance measurement accuracy and power consumption control. The measurement accuracy of the first acquisition circuit directly affects the accuracy of subsequent ratio calculations; a measurement accuracy better than 0.5% is usually required to ensure the reliability of the detection results.

[0086] B2: also includes:

[0087] Control the precharge relay to close, while keeping the main positive relay and the main negative relay open;

[0088] The first acquisition module acquires the third voltage value at the connection point between the first isolation module and the second voltage divider circuit, and the second acquisition module acquires the fourth voltage value at the connection point between the second isolation module and the fourth voltage divider circuit.

[0089] The sticking status of the main and negative relays can be determined by the ratio of the third voltage value to the fourth voltage value of the power battery relay.

[0090] The first acquisition circuit converts the measured voltage value into a digital signal and transmits it to the control unit for processing.

[0091] The logic for detecting high-side relay adhesion is executed.

[0092] Specifically, the sticking state of the main positive relay or pre-charge relay is determined based on the ratio of the first voltage value U1 to the second voltage value U2. When U2 ≤ 5% × U1, the main positive relay or pre-charge relay is determined to be disconnected; when U2 ≥ 95% × U1, the main positive relay or pre-charge relay is determined to be stuck. This judgment standard is based on the following technical principle: when the relay is normally disconnected, there is no electrical connection between the LINK+ point and the PACK+ point, and the voltage measured by the second acquisition circuit should be very small; when the relay is stuck, the LINK+ point and the PACK+ point are connected, and the voltages at the two points are basically equal.

[0093] In an optional implementation, an intermediate judgment interval can also be set. When the ratio is between 5% and 95%, it can be determined that the relay state is uncertain and trigger the repeated detection process.

[0094] It should be noted that the 5% and 95% thresholds were set through extensive experimental verification, ensuring both detection sensitivity and avoiding misjudgments due to measurement errors.

[0095] B3: Prepares for low-side relay detection by controlling the closure of the pre-charge relay.

[0096] Specifically, after completing the high-side relay test, conditions need to be created for the low-side main negative relay test. At this time, the pre-charge relay S2 is closed, while the main positive relay S1 and the main negative relay S3 remain open. The closure of the pre-charge relay provides a voltage path for the detection circuit, allowing the state of the main negative relay to be determined by voltage changes.

[0097] In one alternative implementation, the main positive relay S1 can be closed instead of the pre-charge relay S2. The two are equivalent in detection principle and can be selected according to the system design requirements.

[0098] It should be noted that this step demonstrates the ingenuity of the detection method of the present invention, which achieves the detection of each relay one by one through reasonable relay state control.

[0099] In this embodiment of the application, step S300 involves voltage measurement via a second acquisition circuit, including the following steps C1-C3:

[0100] C1: The first isolation module includes a first optocoupler switch, and the second isolation module includes a second optocoupler switch;

[0101] The first voltage divider circuit of the power battery relay includes a first voltage divider resistor, the second voltage divider circuit of the power battery relay includes a second voltage divider resistor, the third voltage divider circuit of the power battery relay includes a third voltage divider resistor, and the fourth voltage divider circuit of the power battery relay includes a fourth voltage divider resistor.

[0102] The second acquisition circuit is connected to the node between the second optocoupler switch K2 and the fourth voltage divider resistor R4 to measure the voltage value to ground at that point.

[0103] Specifically, such as Figure 5 As shown, the first terminal of the third voltage divider resistor R3 is connected to the second terminal (LINK+ point) of the main positive relay or pre-charge relay, and the second terminal is connected to the fourth voltage divider resistor R4 through the second optocoupler switch K2. The sampling point of the second acquisition circuit is located at the connection node between K2 and R4. When the relay is in different states, the key to this circuit design lies in the parallel connection of the fourth voltage divider resistor R4 and the functional connection module, forming a unique voltage distribution network.

[0104] Circuit analysis shows that when the main negative relay S3 is in different states, the parallel impedance of the functional connection module and R4 will change, thereby affecting the measurement results of the second acquisition circuit. This is the technical principle by which the present invention can detect the state of the low-side relay.

[0105] In one alternative implementation, the resistance value of the fourth voltage divider resistor R4 can be adjusted according to the system voltage level and detection accuracy requirements. It is usually selected to have the same resistance value as the fifth voltage divider resistor R5 to facilitate system tolerance control.

[0106] It should be noted that the design of the second acquisition circuit is an important innovation that distinguishes this invention from the prior art. Through cooperation with the functional connection module, it enables effective detection of the low-side relay.

[0107] In one alternative implementation, the second acquisition circuit may adopt the same design architecture as the first acquisition circuit, including the same ADC and signal conditioning circuitry, to ensure the consistency and comparability of the two acquisitions.

[0108] It should be noted that the synchronization of the two acquisition circuits is crucial to the accuracy of the ratio calculation. It is usually necessary to use synchronous sampling or fast continuous sampling to ensure that the two voltage values ​​reflect the system state at the same moment.

[0109] C2: Various implementation methods and technical characteristics of functional connection modules.

[0110] Specifically, such as Figure 3 and Figure 4 As shown, the functional connection module can be implemented in two ways: the first is to use the fifth voltage divider resistor R5, such as... Figure 1 As shown; the second method is to use the third optocoupler switch K3, such as Figure 4 As shown. When the fifth voltage divider resistor R5 is used, it forms a parallel network with the fourth voltage divider resistor R4. The design with equal resistance values ​​ensures good system symmetry. When the third optocoupler switch K3 is used, a higher isolation voltage can be achieved, making it suitable for applications with stricter electrical isolation requirements.

[0111] The preset reference voltage UREF is set differently for the two implementation methods: when the fifth voltage divider resistor is selected for the functional connection module, it is recommended that UREF be set to 5% × total battery pack voltage; when the third optocoupler switch is selected for the functional connection module, it is recommended that UREF be set to 0.1% × total battery pack voltage.

[0112] In an alternative implementation, a combination of controllable switches and voltage divider resistors can be used to dynamically switch functional connection modules via software control, adapting to different detection requirements.

[0113] It should be noted that the design of the functional connection module embodies the core technical idea of ​​this invention. Through a simple connection module, the technical problem of difficult detection of low-side relays in traditional solutions is solved.

[0114] C3: Design and operating mechanism of the protection circuit.

[0115] Specifically, such as Figure 4 As shown, a diode Z1 can also be installed between the functional connection module and the main negative relay S3. This diode has unidirectional conduction characteristics, with its positive terminal connected to the functional connection module and its negative terminal connected to the main negative relay. The main functions of the diode include: 1) acting as a protection device for the detection circuit to prevent surge voltage at the load end from damaging the detection circuit; 2) acting as a voltage divider to further optimize voltage distribution; and 3) providing unidirectional conduction characteristics to prevent reverse current from affecting detection accuracy.

[0116] The selection of a diode requires consideration of its forward voltage, reverse voltage withstand capability, and temperature characteristics. Schottky diodes are typically chosen due to their low forward voltage and fast switching characteristics.

[0117] In one alternative implementation, the protection circuit may also include components such as TVS diodes (transient voltage suppressors) and varistors to form multi-level protection and further improve circuit reliability.

[0118] It should be noted that the design of the protection circuit not only improves the reliability of the system, but also provides the detection circuit with an additional voltage reference adjustment function, demonstrating the ingenuity of the circuit design.

[0119] In this embodiment of the application, step S400, which determines the relay state based on the voltage ratio, includes the following steps D1-D4:

[0120] D1: Determining the sticking status of the main negative relay based on the ratio of the third voltage value to the fourth voltage value of the power battery relay includes:

[0121] When the fourth voltage value of the power battery relay is greater than 95% of the third voltage value of the power battery relay, it is determined that the main negative relay of the power battery relay is disconnected.

[0122] When the fourth voltage value of the power battery relay is less than the preset reference voltage, it is determined that the main and negative relays of the power battery relay are stuck.

[0123] The complete judgment logic and technical principle of main and negative relay detection.

[0124] Specifically, the detection of the main negative relay is based on the following technical principle: When the precharge relay S2 is closed, if the main negative relay S3 is normally open, there is no electrical connection between the LINK-point and the PACK-point, and the voltage U4 measured by the second acquisition circuit should be close to the voltage U3 measured by the first acquisition circuit; if the main negative relay S3 is stuck, the LINK-point and the PACK-point will be connected, and the voltage divider network formed by the functional connection module will cause the measured value of the second acquisition circuit to drop significantly.

[0125] The judgment criteria are as follows: when U4 ≥ 95% × U3, the main negative relay is determined to be disconnected; when U4 ≤ UREF, the main negative relay is determined to be stuck. The technical basis for this judgment logic is that the parallel effect of the functional connection module and the fourth voltage divider resistor R4 will change according to the state of the main negative relay.

[0126] In an alternative implementation, time series analysis can be combined to improve detection accuracy by monitoring the dynamic characteristics of voltage changes, especially for adhesion cases with high contact resistance.

[0127] It should be noted that the detection of the main negative relay is the most innovative part of this invention. Traditional solutions have difficulty effectively detecting the low-side relay, and this invention solves this technical problem through the ingenious design of the functional connection module.

[0128] The control unit calculates the ratio of the first voltage value to the second voltage value and compares it with a preset threshold.

[0129] Specifically, the ratio is calculated using the formula: Ratio = Second voltage value / First voltage value × 100%

[0130] When all relays are in the open state, if the main positive relay or precharge relay is normally disconnected, the second voltage value should be very small, close to zero; if the relays are stuck, the second voltage value will be close to the first voltage value. According to the judgment criteria: when the second voltage value is ≤ 5% × the first voltage value, the relay is determined to be disconnected; when the second voltage value is ≥ 95% × the first voltage value, the relay is determined to be stuck.

[0131] In an alternative implementation, an intermediate state judgment range can also be set. For example, when the ratio is between 5% and 95%, the relay state is determined to be uncertain, requiring repeated testing or confirmation by other auxiliary means.

[0132] It should be noted that the setting of the threshold needs to take into account factors such as the measurement accuracy of the system, the influence of ambient temperature, and device aging. Usually, it is necessary to determine the appropriate threshold range through statistical analysis of a large amount of experimental data.

[0133] D2: Also includes a functional connection module, the power battery relay functional connection module is connected between the third voltage divider circuit of the power battery relay and the main negative relay;

[0134] The power battery relay functional connection module includes a fifth voltage divider resistor or a third optocoupler switch;

[0135] A diode is also provided between the power battery relay functional connection module and the main negative relay of the power battery relay. The positive terminal of the power battery relay diode is connected to the power battery relay functional connection module, and the negative terminal of the power battery relay diode is connected to the main negative relay.

[0136] Perform a test on the main negative relay, control the pre-charge relay S2 to close, and keep other relays in the open state.

[0137] Specifically, after completing the detection of the main positive relay or pre-charge relay, the status of the main negative relay needs to be further detected. At this time, the pre-charge relay S2 is closed, providing a voltage reference for the detection circuit through the pre-charge relay. The first acquisition circuit continues to measure the voltage of PACK+ point to ground, which is recorded as the third voltage value; the second acquisition circuit measures the voltage of LINK+ point to ground, which is recorded as the fourth voltage value.

[0138] According to the detection logic: when the fourth voltage value is ≥ 95% × the third voltage value, the main negative relay is determined to be disconnected; when the fourth voltage value is ≤ UREF (preset reference voltage), the main negative relay is determined to be stuck.

[0139] In one optional implementation, the preset reference voltage UREF can be adjusted according to different implementation methods of the functional connection module. When the functional connection module uses the fifth voltage divider resistor, it is recommended that UREF be selected as 5% × total battery pack voltage; when the third optocoupler switch is used, it is recommended that UREF be selected as 0.1% × total battery pack voltage.

[0140] It should be noted that the detection of the main negative relay is more complex than that of the high-side relay because a suitable voltage reference needs to be established through the functional connection module, which is one of the important innovations of this invention.

[0141] D3: The first voltage divider resistor of the power battery relay, the first end of which is connected to the positive terminal of the high side of the battery pack, and the second end is connected to the second voltage divider resistor through the first optocoupler switch;

[0142] The third voltage divider resistor has its first end connected to the second end of the main positive relay or precharge relay, and its second end connected to the fourth voltage divider resistor through the second optocoupler switch.

[0143] The first acquisition circuit is connected between the first optocoupler switch of the power battery relay and the second voltage divider resistor of the power battery relay.

[0144] The second acquisition circuit is connected between the second optocoupler switch of the power battery relay and the fourth voltage divider resistor of the power battery relay.

[0145] The specific implementation and protection measures of the functional connection module.

[0146] Specifically, such as Figure 3 and Figure 4 As shown, the functional connection module 4 is connected between the third voltage divider resistor R3 and the main negative relay S3. The functional connection module can be implemented using either the fifth voltage divider resistor R5 or the third optocoupler switch K3. When using a voltage divider resistor, R5 and R4 are connected in parallel to form a voltage divider network; when using an optocoupler switch, better high-low voltage isolation can be achieved.

[0147] like Figure 4 As shown, a diode Z1 can also be installed between the functional connection module and the main negative relay. The positive terminal of this diode is connected to the functional connection module, and the negative terminal is connected to the main negative relay. The diode serves as a protective device for the detection circuit, preventing surges at the load end from damaging related components of the detection circuit, and also acts as a voltage divider.

[0148] In one alternative implementation, the functional connection module may also include other protective elements, such as fuses, varistors, or TVS diodes, to further improve the reliability and safety of the circuit.

[0149] It should be noted that the design of the functional connection module is the core innovation of this invention. Through ingenious circuit design, it is possible to complete the detection of the status of all relays with fewer components, which greatly reduces the system cost and complexity.

[0150] Scientific basis and optimization methods for threshold setting.

[0151] Specifically, the threshold settings in this invention are based on a large amount of experimental data and theoretical analysis. The 5% and 95% judgment thresholds take into account the following factors: 1) the influence of measurement accuracy, the measurement error of ADC is usually in the range of 1% to 2%; 2) the influence of temperature change on resistance value, the temperature coefficient of metal film resistor is about 100ppm / ℃; 3) the change of relay contact resistance, under normal circumstances the contact resistance should be less than a few milliohms; 4) the influence of system noise and interference.

[0152] The preset reference voltage UREF is calculated based on the voltage divider principle: when the functional connection module is R5, UREF = total battery pack voltage × R4 / (R4 + R5) ≈ 50% × total battery pack voltage. Considering the detection margin, it is set to 5% × total battery pack voltage. When the functional connection module is K3, the impedance is very small in the conducting state, and UREF is set to 0.1% × total battery pack voltage. In an optional implementation, the threshold can also be dynamically adjusted according to the system operating environment and historical data, using machine learning algorithms to optimize the judgment accuracy. It should be noted that a scientific threshold setting is key to ensuring detection accuracy. This invention determines a suitable judgment standard through a combination of theoretical analysis and experimental verification.

[0153] D4: Analysis of the technical advantages in system integration and practical applications.

[0154] Specifically, this invention has the following significant advantages over existing technologies: 1) Simplified circuitry: Traditional solutions require designing an independent detection circuit for each relay, while this invention only requires two acquisition circuits to detect all relays; 2) Reduced cost: The number of high-voltage acquisition circuits is reduced, significantly lowering system costs; 3) Improved reliability: The design of isolation modules and unidirectional diodes greatly reduces the impact of high-voltage system capacitance; 4) Simplified diagnostic logic: Unified detection methods and judgment criteria make software implementation simpler; 5) Good real-time performance: No complex insulation detection waiting time is required, resulting in fast detection speed.

[0155] In practical applications, this invention is particularly suitable for the power battery management system of new energy vehicles, and can quickly complete the relay status detection before the vehicle starts, ensuring the safe and reliable operation of the high-voltage system.

[0156] In one alternative implementation, the present invention can also be integrated with other safety monitoring systems, such as insulation monitoring and high-voltage interlocking, to form a complete battery safety management system.

[0157] It should be noted that this invention not only solves the technical problem of relay detection, but also provides important technical support for the safety management of the entire power battery system, and has broad application prospects.

[0158] In summary, this invention, through the organic combination of the above steps, achieves effective detection of the sticking state of high-side and low-side relays in a power battery system. Compared with traditional solutions, this invention has advantages such as simple circuit structure, clear detection logic, low system cost, and high reliability, providing important technical support for the safe management of power batteries.

[0159] Example 3

[0160] The above is a schematic scheme for a method of detecting the sticking state of a power battery relay. It should be noted that the technical solution of this power battery relay sticking state detection system and the technical solution of the aforementioned power battery relay sticking state detection method belong to the same concept. Details not described in detail in this embodiment of the power battery relay sticking state detection system can be found in the description of the aforementioned power battery relay sticking state detection method.

[0161] This embodiment also provides a power battery relay adhesion detection system, including:

[0162] The control module is used to control the first isolation module and the second isolation module to be turned on, and at the same time to control the main positive relay, the precharge relay and the main negative relay to be turned off.

[0163] The voltage acquisition module is used to acquire the first voltage value at the connection point between the first isolation module and the second voltage divider circuit, and the second voltage value at the connection point between the second isolation module and the fourth voltage divider circuit.

[0164] The status judgment module is used to determine the sticking status of the main positive relay or the precharge relay based on the ratio of the first voltage value of the power battery relay to the second voltage value of the power battery relay.

[0165] This embodiment also provides an electronic device suitable for detecting the sticking state of a power battery relay, comprising: a memory and a processor; the memory is used to store computer-executable instructions, and the processor is used to execute the computer-executable instructions to implement the power battery relay sticking state detection method proposed in the above embodiment.

[0166] This embodiment also provides a storage medium storing a computer program, which, when executed by a processor, implements the method for detecting the sticking state of a power battery relay as proposed in the above embodiments.

[0167] The storage medium proposed in this embodiment and the method for detecting the sticking state of the power battery relay proposed in the above embodiments belong to the same inventive concept. Technical details not described in detail in this embodiment can be found in the above embodiments, and this embodiment has the same beneficial effects as the above embodiments.

[0168] Based on the above description of the implementation methods, those skilled in the art will clearly understand that the present invention can be implemented using software and necessary general-purpose hardware, and of course, it can also be implemented using hardware. Based on this understanding, the technical solution of the present invention, or the part that contributes to the prior art, can be embodied in the form of a software product. This computer software product can be stored in a computer-readable storage medium, such as a computer floppy disk, read-only memory (ROM), random access memory (RAM), flash memory, hard disk, or optical disk, etc., including several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute the methods of the various embodiments of the present invention.

[0169] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A method for detecting the sticking state of a power battery relay, characterized in that: This includes controlling the first and second isolating switches to be turned on, and controlling the main positive relay, precharge relay and main negative relay to be turned off; The first voltage value at the connection point between the first isolation switch and the second voltage divider resistor is measured by the first acquisition circuit. The second voltage value at the connection point between the second isolation switch and the fourth voltage divider resistor is measured by the second acquisition circuit. The sticking status of the main positive relay or the precharge relay is determined based on the ratio of the first voltage value to the second voltage value.

2. The method for detecting the sticking state of a power battery relay as described in claim 1, characterized in that: Determining the sticking status of the main positive relay or precharge relay based on the ratio of the first voltage value to the second voltage value includes: When the second voltage value is less than 5% of the first voltage value, it is determined that the main positive relay or the precharge relay is disconnected; When the second voltage value is greater than 95% of the first voltage value, it is determined that the main positive relay or the precharge relay is stuck.

3. The method for detecting the sticking state of a power battery relay as described in claim 2, characterized in that: Also includes: Control the precharge relay to close, while keeping the main positive relay and the main negative relay open; The first acquisition module acquires the third voltage value at the connection point between the first isolation module and the second voltage divider circuit, and the second acquisition module acquires the fourth voltage value at the connection point between the second isolation module and the fourth voltage divider circuit. The sticking status of the main negative relay is determined based on the ratio of the third voltage value to the fourth voltage value.

4. The method for detecting the sticking state of a power battery relay as described in claim 3, characterized in that: Determining the sticking state of the main negative relay based on the ratio of the third voltage value to the fourth voltage value includes: When the fourth voltage value is greater than 95% of the third voltage value, it is determined that the main negative relay is disconnected; When the fourth voltage value is less than the preset reference voltage, it is determined that the main negative relay is stuck.

5. The method for detecting the sticking state of a power battery relay as described in claim 4, characterized in that: The first isolation module includes a first optocoupler switch, and the second isolation module includes a second optocoupler switch; The first voltage divider circuit includes a first voltage divider resistor, the second voltage divider circuit includes a second voltage divider resistor, the third voltage divider circuit includes a third voltage divider resistor, and the fourth voltage divider circuit includes a fourth voltage divider resistor.

6. The method for detecting the sticking state of a power battery relay as described in claim 5, characterized in that: It also includes a functional connection module, which is connected between the third voltage divider circuit and the main negative relay; The functional connection module includes a fifth voltage divider resistor or a third optocoupler switch; A diode is also provided between the functional connection module and the main negative relay. The positive terminal of the diode is connected to the functional connection module, and the negative terminal of the diode is connected to the main negative relay.

7. The method for detecting the sticking state of a power battery relay as described in claim 6, characterized in that: The first voltage divider resistor has a first end connected to the positive terminal of the high side of the battery pack, and a second end connected to the second voltage divider resistor through a first optocoupler switch; The third voltage divider resistor has its first end connected to the second end of the main positive relay or precharge relay, and its second end connected to the fourth voltage divider resistor through the second optocoupler switch. The first acquisition circuit is connected between the first optocoupler switch and the second voltage divider resistor; The second acquisition circuit is connected between the second optocoupler switch and the fourth voltage divider resistor.

8. A power battery relay adhesion state detection system, based on the power battery relay adhesion state detection method according to any one of claims 1 to 7, characterized in that: It also includes a control module, used to control the first isolation module and the second isolation module to be turned on, while controlling the main positive relay, the precharge relay and the main negative relay to be turned off; The voltage acquisition module is used to acquire the first voltage value at the connection point between the first isolation module and the second voltage divider circuit, and the second voltage value at the connection point between the second isolation module and the fourth voltage divider circuit. The status judgment module is used to determine the sticking status of the main positive relay or the precharge relay based on the ratio of the first voltage value to the second voltage value.

9. A computer device comprising a memory and a processor, wherein the memory stores a computer program, characterized in that: When the processor executes the computer program, it implements the steps of the power battery relay adhesion state detection method according to any one of claims 1 to 7.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by the processor, it implements the steps of the power battery relay adhesion state detection method according to any one of claims 1 to 7.

Images