BMS cathode relay and main positive relay adhesion diagnosis circuit

Abstract

The invention discloses a BMS cathode relay and main positive relay adhesion diagnosis circuit, cathode relay adhesion diagnosis and main positive relay adhesion diagnose.The cathode relay adhesion diagnosis process includes the steps that power is supplied through a battery pack module, a main negative relay is kept in a disconnected state, and when the main negative relay is in a disconnected instruction, the voltage HV2V5 collected by an HVAD2 port is converted into the voltage HV2V5; and at the moment, it is judged that the relay is disconnected, the sampling line is normally connected, a relay disconnection instruction is sent, and the HVAD2 is not 2.5 V, the relay is adhered or the sampling line is disconnected, the main positive relay adhesion diagnosis process comprises the steps that power is supplied through a battery pack module, the main positive relay is kept in a disconnected state, when the main positive relay is disconnected, the voltage collected by the HVAD1 is 2V5, and when the voltage collected by the HVAD2 is 2V5, the main positive relay is connected with the HVAD2. And if the voltage is not 2V5, the relay is adhered or the sampling line is broken. Therefore, the detection precision of the high-voltage cathode relay and the main positive relay is improved, the detection reliability is improved, and the risk of misjudgment of the state of the main positive relay is avoided.

Description

Technical Field

[0001] The present invention relates to the technical field of circuit diagnosis, and particularly to a BMS negative relay and main positive relay adhesion diagnosis circuit. Background Art

[0002] In the battery management system (BMS, Battery Management System) of electric vehicles and energy storage systems, the status monitoring of high-voltage negative relays and main positive relays is crucial for ensuring the safe and stable operation of the system. However, existing technologies face a series of challenges in implementing these functions.

[0003] 1. Voltage acquisition problem when the high-voltage negative relay is closed

[0004] When the high-voltage negative relay is closed, the negative electrode it connects becomes the reference ground of the entire battery system. In this configuration, a common ADC (analog-to-digital converter) acquisition circuit will encounter a problem when attempting to measure voltage: since the reference ground of the ADC acquisition port is also connected to the high voltage negative electrode, the acquired voltage is actually at 0 potential. This situation causes the ADC to be unable to directly identify and report the actual voltage value because all voltage measurements are relative to this common reference ground. This limits the ability of the BMS to monitor the status of the high-voltage negative relay because it is impossible to determine whether the relay is closed through a simple voltage measurement.

[0005] 2. Limitations of traditional BMS high-voltage negative detection circuits

[0006] Traditional BMS high-voltage negative detection circuits do not fully consider the complexity of the status monitoring of high-voltage negative relays and main positive relays during design. These circuits usually rely on direct voltage measurements to judge the status of the relays, but they cannot directly identify the specific status of the high-voltage negative relay and the main positive relay. For example, when the high-voltage negative relay is closed, due to the reference ground problem, the traditional circuit cannot accurately judge the status of the relay. Similarly, for the main positive relay, the traditional circuit also lacks a method to actively identify its status, which limits the ability of the BMS in fault prediction and diagnosis.

[0007] 3. Challenges in identifying the status of the main positive relay

[0008] Traditional methods for identifying the status of the main positive relay mainly rely on voltage measurement after closing. A significant drawback of this method is that it is vulnerable to other factors, leading to misjudgment. For example, when there is a broken wire in the circuit, since the voltage difference across the broken wire point is zero, the measured voltage value will also be 0V. In this case, the BMS may incorrectly determine that the main positive relay is in a stuck state (i.e., the relay remains closed when it should not be), which may lead to serious safety problems. In addition, even when there is no broken wire, due to the uncertainty of voltage measurement and noise interference, the traditional method may also result in a decrease in the accuracy of status identification. Summary of the Invention

[0009] The present invention aims to solve at least one of the technical problems in the related art to some extent.

[0010] To this end, the object of the present invention is to propose a BMS negative relay and main positive relay adhesion diagnosis circuit, which directly and real-time detects the status of the high-voltage negative relay, does not rely on other detection circuit resources, optimizes the high-voltage negative sampling circuit, reduces the actual operation cost, improves the detection accuracy of the high-voltage negative relay and the main positive relay, enhances the reliability of detection, and avoids the risk of misjudging the status of the main positive relay.

[0011] To achieve the above object, the present invention proposes a BMS negative relay and main positive relay adhesion diagnosis circuit, and the diagnosis method includes: negative relay adhesion diagnosis and main positive relay adhesion diagnosis, wherein,

[0012] The process of diagnosing the adhesion of the negative relay is as follows: power is supplied through the battery pack module, the main negative relay remains in the open state. When the main negative relay is commanded to open, the voltage HV_2V5 collected at the HV_AD2 port is used to determine whether the relay is open at this time, and if the sampling line is connected normally, a relay open command is sent. If HV_AD2 is not 2.5V or other voltages, then there is a situation where the relay is stuck or the sampling line is open.

[0013] When the main negative relay is closed, the voltage collected at HV_AD2 is the voltage divided by R2 and R4.

[0014] The formula for the voltage collected at the AD port when the main negative relay is closed is:

[0015]

[0016] Wherein, HV_AD2 is the high-voltage sampling ADC2, 2V5 is the high-voltage power supply of 2.5V, and R2 and R4 are the high-voltage sampling voltage-dividing resistors at the output end of the main negative relay.

[0017] The adhesion diagnosis process of the main positive relay is as follows: Power is supplied through the battery pack module, and the main positive relay remains in the open state. When the main positive relay is open, the voltage collected by HV_AD1 is 2V5. If the voltage is not 2V5, there is a situation where the relay is adhered or the sampling line is broken.

[0018] When the main positive relay is closed, it divides the voltage between R1 and R3. For the specific voltage calculation, refer to Formula 2. If the voltage is 2V5, the relay has a fault and cannot be closed.

[0019] The voltage formula collected by the AD port when the main positive relay is closed is:

[0020]

[0021] Among them, HV_AD2 is the high-voltage sampling ADC1, HV_2V5 is the high-voltage power supply of 2.5V, VBAT is the battery pack module, and R1 and R3 are the high-voltage sampling voltage-dividing resistors at the output end of the main positive relay.

[0022] The adhesion diagnosis circuit of the BMS negative relay and the main positive relay of the present invention directly and real-time detects the state of the high-voltage negative relay, does not rely on other detection circuit resources, optimizes the high-voltage negative sampling circuit, reduces the actual operation cost, improves the detection accuracy of the high-voltage negative relay and the main positive relay, enhances the detection reliability, and avoids the risk of misjudging the state of the main positive relay.

[0023] In addition, the adhesion diagnosis circuit of the BMS negative relay and the main positive relay proposed according to the above application also has the following additional technical features:

[0024] Specifically, the adhesion diagnosis steps of the negative relay are as follows:

[0025] Power is supplied through the battery pack module. At this time, the main negative relay remains in the open state. The voltage of the negative relay is collected through AD2, and then it is judged whether the collected voltage is 2V5.

[0026] Judge whether the voltage is 2V5. If it is, the relay is normally open. Then, a relay closing instruction is sent. Otherwise, it is reported that the relay is adhered and the relay closing action is stopped, and finally it stops.

[0027] After sending the relay closing instruction, the voltage of the negative relay is collected through AD2. Then, it is judged again whether the collected voltage is 2V5. If the judged voltage is 2V5, it is reported that the relay is adhered and the relay closing action is stopped, and finally the diagnosis stops. Otherwise, the relay diagnosis is completed and the relay works normally.

[0028] Specifically, the adhesion diagnosis steps of the main relay are as follows:

[0029] Powered by the battery pack module. At this time, the main positive relay remains open, and the voltage of the negative relay is collected through AD1 to determine whether the collected voltage is 2.5V;

[0030] Judge whether the voltage is 2.5V. If it is, judge that the relay is normally open, and then send a relay closing command. Otherwise, report that the relay is stuck and stop the closing relay operation, and finally stop;

[0031] After sending the relay closing command, collect the voltage of the negative relay through AD1, and then judge again whether the collected voltage is 2.5V. If the judged voltage is 2.5V, report that the relay is stuck and stop the closing relay operation, and finally stop the diagnosis. Otherwise, the relay diagnosis is completed and the relay works normally.

[0032] Specifically, it further includes a circuit system. The circuit system includes a battery pack module, a main positive relay, a main negative relay, resistors R1, R2, R3, R4, a power supply module, a grounding unit, and a sampling module. Among them, the battery pack module is electrically connected to the main positive relay and the main negative relay; the power supply module is electrically connected to the resistors R1, R2, R3, and R4; the resistors R1 and R2 are electrically connected to the main positive relay; the resistors R3 and R4 are electrically connected to the main negative relay; the battery pack module is electrically connected to the grounding unit; the sampling module is electrically connected to the resistors R1, R2, R3, and R4.

[0033] Specifically, the main positive relay is electrically connected to the positive output switch relay of the battery pack module, and the main negative relay is electrically connected to the negative output switch relay of the battery pack module.

[0034] Specifically, the sampling module includes a high-voltage sampling unit one and a high-voltage sampling unit two. Among them, the high-voltage sampling unit one is electrically connected to the resistors R1 and R2; the high-voltage sampling unit two is electrically connected to the resistors R3 and R4.

[0035] Specifically, the high-voltage sampling unit one is the voltage sampling unit at the rear end of the main positive relay, and the high-voltage sampling unit two is the voltage sampling unit at the rear end of the main negative relay.

[0036] The additional aspects and advantages of the present invention will be partially given in the following description, partially become obvious from the following description, or be understood through the practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] The above and / or additional aspects and advantages of the present invention will become obvious and easy to understand from the following description of the embodiments in conjunction with the drawings, where:

[0038] Figure 1 This is the flowchart for judging the working state of the main negative relay of the present invention;

[0039] Figure 2 This is the flowchart for judging the working state of the main positive relay of the present invention;

[0040] Figure 3 This is the circuit diagram of the high-voltage system loop. Detailed implementation manners

[0041] The embodiments of the present invention will be described in detail below. The examples of the embodiments are shown in the accompanying drawings, where the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below by referring to the accompanying drawings are exemplary and are intended to explain the present invention and should not be construed as limiting the present invention. On the contrary, the embodiments of the present invention include all changes, modifications, and equivalents falling within the spirit and scope of the appended claims.

[0042] The BMS negative relay and the main positive relay adhesion diagnosis circuit of the embodiments of the present invention will be described below with reference to the accompanying drawings.

[0043] Figures 1 - 3 As shown, the diagnosis method of the BMS negative relay and the main positive relay adhesion diagnosis circuit of the embodiments of the present invention includes: negative relay adhesion diagnosis and main positive relay adhesion diagnosis, where

[0044] The negative relay adhesion diagnosis process is as follows: power is supplied through the battery pack module, the main negative relay remains in the open state. When the main negative relay disconnection command is issued, the voltage HV_2V5 collected by the HV_AD2 port. At this time, it is judged that the relay is disconnected and the sampling line is connected normally. When the relay disconnection command is sent and HV_AD2 is not 2.5V or other voltages, it means that the relay is stuck or the sampling line is open.

[0045] When the main negative relay is closed, the voltage collected by HV_AD2 is the voltage divided by the resistor R2 and the resistor R4.

[0046] It should be noted that the voltage collected by HV_AD2 is divided by the resistors R2 and R4. Combining the disconnection command and the closing command of the main negative relay, when judging disconnection and closing, it is only necessary to judge whether HV_AD2 can collect a voltage of 2.5V to judge the fault state of the main negative relay.

[0047] The voltage formula collected by the AD port when the main negative relay is closed is:

[0048]

[0049] Among them, HV_AD2 is the high-voltage sampling ADC2, 2V5 is the high-voltage power supply of 2.5V, and R2 and R4 are the high-voltage sampling voltage-dividing resistors at the back end of the main negative relay output;

[0050] Main negative relay diagnostic truth table:

[0051] Main negative relay instruction HV_AD2 Main negative relay fault status Disconnect instruction 2V5 Normal Disconnect instruction Voltage division of R4 and R2 Relay adhesion Close instruction Voltage division of R4 and R2 Normal Close instruction 2V5 Relay has a fault and cannot close

[0052] The diagnostic process for the main positive relay sticking is as follows: The battery pack module is used for power supply, and the main positive relay remains in the open state. When the main positive relay is open, the voltage collected by HV_AD1 is 2V5. If the voltage is not 2V5, it means that the relay is stuck or the sampling line is broken;

[0053] When the main positive relay is closed, R1 and R3 are used for voltage division. For the specific voltage calculation, refer to Formula 2. If the voltage is 2V5, it means that the relay has a fault and cannot be closed;

[0054] The voltage formula for the AD port of the main positive relay when it is closed is:

[0055]

[0056] Among them, HV_AD2 is the high-voltage sampling ADC1, HV_2V5 is the high-voltage power supply of 2.5V, VBAT is the battery pack module, and R1 and R3 are the high-voltage sampling voltage-dividing resistors at the back end of the main positive relay output.

[0057] It should be noted that the voltage collected by HV_AD1 is divided by resistors R1 and R3. Combining the open and close commands of the main positive relay, when judging the open and close states, it is only necessary to judge whether HV_AD1 can collect a 2.5V voltage to determine the fault state of the main positive relay.

[0058] Main positive relay diagnostic truth table:

[0059] Main negative relay instruction HV_AD1 Main positive relay fault status Disconnect instruction 2V5 Normal Disconnect instruction Voltage division of R3 and R1 Relay adhesion Close instruction Voltage division of R3 and R1 Normal Close instruction 2V5 Relay has a fault and cannot close

[0060] Specifically, the steps for diagnosing the sticking of the negative relay are as follows:

[0061] The battery pack module is used for power supply. At this time, the main negative relay remains in the open state, and the voltage of the negative relay is collected through AD2 to judge whether the collected voltage is 2V5;

[0062] Judge whether the voltage is 2V5. If it is, the relay is normally open. Then, send a relay closing command. Otherwise, report that the relay is stuck and stop the closing action of the relay, and finally stop;

[0063] After sending the relay closing instruction, the negative relay voltage is collected through AD2. Subsequently, it is determined again whether the collected voltage is 2V5. If the voltage is determined to be 2V5, it is reported that the relay is stuck and the relay closing action is stopped, and finally the diagnosis is stopped. Otherwise, the relay diagnosis is completed and the relay works normally.

[0064] Specifically, the main pole relay sticking diagnosis steps are as follows:

[0065] Power is supplied through the battery pack module. At this time, the main positive relay remains in the open state, and the voltage of the negative relay is collected through AD1 to determine whether the collected voltage is 2V5;

[0066] Determine whether the voltage is 2V5. If so, it is determined that the relay is normally open, and then the relay closing instruction is sent. Otherwise, it is reported that the relay is stuck and the relay closing action is stopped, and finally it stops;

[0067] After sending the relay closing instruction, the negative relay voltage is collected through AD1. Subsequently, it is determined again whether the collected voltage is 2V5. If the voltage is determined to be 2V5, it is reported that the relay is stuck and the relay closing action is stopped, and finally the diagnosis is stopped. Otherwise, the relay diagnosis is completed and the relay works normally.

[0068] Specifically, it further includes a circuit system, which includes a battery pack module, a main positive relay, a main negative relay, resistors R1, R2, R3, R4, a power supply module, a grounding unit, and a sampling module.

[0069] Among them, the battery pack module is electrically connected to the main positive relay and the main negative relay in an output manner, and the power supply module is electrically connected to resistors R1, R2, R3, and R4 in an output manner. Resistors R1 and R2 are electrically connected to the main positive relay, resistors R3 and R4 are electrically connected to the main negative relay, the battery pack module is electrically connected to the grounding unit, and the sampling module is electrically connected to resistors R1, R2, R3, and R4.

[0070] It should be noted that the battery pack module is a VBAT module. The battery pack module is electrically connected to the main positive relay and the main negative relay respectively. The main positive relay is electrically connected to the positive output switch relay of the battery pack module, and the main negative relay is electrically connected to the negative output switch relay of the battery pack module.

[0071] Furthermore, the sampling module includes a high-voltage sampling unit one and a high-voltage sampling unit two.

[0072] Among them, the high-voltage sampling unit one is electrically connected to resistors R1 and R2, and the high-voltage sampling unit two is electrically connected to resistors R3 and R4.

[0073] It should be noted that the high-voltage sampling unit 1 samples the voltage division on the pair of resistors R1 and R2, while the high-voltage sampling unit 2 samples the voltage division on the resistors R3 and R4.

[0074] Specifically, the high-voltage sampling unit 1 is the voltage sampling unit at the rear end of the main positive relay, and the high-voltage sampling unit 2 is the voltage sampling unit at the rear end of the main negative relay.

[0075] In summary, the BMS negative relay and the main positive relay adhesion diagnosis circuit of the embodiment of the present invention directly and real-time detects the state of the high-voltage negative relay, does not rely on other detection circuit resources, optimizes the high-voltage negative sampling circuit, reduces the actual operation cost, improves the detection accuracy of the high-voltage negative relay and the main positive relay, enhances the detection reliability, and avoids the risk of misjudging the state of the main positive relay.

[0076] Although the embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those of ordinary skill in the art can make changes, modifications, substitutions, and variations to the above embodiments within the scope of the present invention.

Claims

1. A BMS negative relay and main positive relay adhesion diagnosis circuit, characterized in that: The diagnostic method includes: negative relay adhesion diagnosis and main positive relay adhesion diagnosis, among which, The negative relay adhesion diagnosis process is as follows: power is supplied by the battery pack module, the main negative relay remains disconnected, and when the main negative relay is disconnected, the voltage HV_2V5 collected at the HV_AD2 port is judged to be disconnected, and the sampling line is connected normally, and a relay disconnection command is sent. If HV_AD2 is not 2.5V, the relay is adhered or the sampling line is broken; When the main negative relay is closed, the voltage collected by HV_AD2 is the divided voltage of resistors R2 and R4; The voltage formula collected by closing the main negative relay AD port is: Among them, HV_AD2 is the high-voltage sampling ADC2, 2V5 is the high-voltage power supply 2.5V, and resistors R2 and R4 are the high-voltage sampling voltage divider resistors at the back end of the main negative relay output; The main positive relay adhesion diagnosis process is: power is supplied by the battery pack module, the main positive relay remains disconnected, when the main positive relay is disconnected, the voltage collected by HV_AD1 is 2V5, if the voltage is not 2V5, the relay is adhered or the sampling line is disconnected; When the main positive relay is closed, the resistor R1 and the resistor R3 divide the voltage. For specific voltage calculation, refer to formula 2. If the voltage is 2V5, the relay is faulty and cannot be closed. The voltage formula collected by closing the main positive relay AD port is: Among them, HV_AD2 is the high-voltage sampling ADC1, HV_2V5 is the high-voltage power supply 2.5V, VBAT is the battery pack module, and resistors R1 and R3 are the high-voltage sampling divider resistors at the back end of the main positive relay output.

2. The BMS negative relay and main positive relay adhesion diagnosis circuit according to claim 1, characterized in that: The steps for diagnosing the negative relay sticking are: The battery pack module is used for power supply. At this time, the main negative relay remains disconnected. The voltage of the negative relay is collected through AD2 to determine whether the collected voltage is 2V5. Determine whether the voltage is 2V5. If it is, the relay is normally disconnected, and then a relay closing command is sent. If it is not, the relay adhesion is reported to stop the closing relay action and finally stop; After sending the relay closing command, the negative relay voltage is collected through AD2, and then it is judged again whether the collected voltage is 2V5. If the voltage is 2V5, the relay adhesion is reported and the closing relay action is stopped. Finally, the diagnosis is stopped. Otherwise, the relay diagnosis is completed and the relay is working normally.

3. The BMS negative relay and main positive relay adhesion diagnosis circuit according to claim 1, characterized in that: The steps for diagnosing main pole relay adhesion are: The battery pack module is used for power supply. At this time, the main positive relay remains disconnected. The voltage of the negative relay is collected through AD1 to determine whether the collected voltage is 2V5. Determine whether the voltage is 2V5. If it is, the relay is considered to be normally disconnected, and then a relay closing command is sent. If it is not, the relay adhesion is reported to stop the closing relay action and finally stop. After sending the relay closing command, the negative relay voltage is collected through AD1, and then it is judged again whether the collected voltage is 2V5. If the voltage is 2V5, the relay adhesion is reported to stop the closing relay action, and finally the diagnosis is stopped. Otherwise, the relay diagnosis is completed and the relay is working normally.

4. The BMS negative relay and main positive relay adhesion diagnosis circuit according to claim 1, characterized in that: It also includes a circuit system, which includes a battery pack module, a main positive relay, a main auxiliary relay, a resistor R1, a resistor R2, a resistor R3, a resistor R4, a power supply module, a grounding unit and a sampling module, wherein: The battery pack module is electrically outputted to connect the main positive relay and the main negative relay; The power supply module is electrically connected to the resistor R1, the resistor R2, the resistor R3 and the resistor R4; The resistor R1 and the resistor R2 are electrically connected to the main positive relay; The resistor R3 and the resistor R4 are electrically connected to the main negative relay; The battery pack module is electrically connected to the grounding unit; The sampling module is electrically connected to the resistor R1 , the resistor R2 , the resistor R3 , and the resistor R4 .

5. The BMS negative relay and main positive relay adhesion diagnosis circuit according to claim 4, characterized in that: The main positive relay is electrically connected to the positive output switch relay of the battery pack module, and the main negative relay is electrically connected to the negative output switch relay of the battery pack module.

6. The BMS negative relay and main positive relay adhesion diagnosis circuit according to claim 4, characterized in that: The sampling module includes a high-voltage sampling unit 1 and a high-voltage sampling unit 2, wherein: The high voltage sampling unit 1 is electrically connected to the resistor R1 and the resistor R2; The second high voltage sampling unit is electrically connected to the resistor R3 and the resistor R4.

7. The BMS negative relay and main positive relay adhesion diagnosis circuit according to claim 6, characterized in that: The first high-voltage sampling unit is a main positive relay rear end voltage sampling unit, and the second high-voltage sampling unit is a main negative relay rear end voltage sampling unit.

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