New energy automobile insulation early warning method and system

Abstract

The invention discloses a new energy automobile insulation early warning method and system. The method comprises the steps that voltage information of a battery is collected, and an insulation value is calculated according to the voltage information; the current state of the vehicle is judged, early warning control is carried out according to the early warning strategy corresponding to the state in combination with the insulation value, and the early warning strategy estimates the risk of future insulation fault occurrence according to the calculated insulation value and outputs an early warning alarm. The method has the advantages that insulation early warning is achieved in advance, whether the battery pack insulation fault or the other high-voltage part insulation fault of the whole vehicle exists is directly distinguished, and the accuracy and efficiency of insulation fault diagnosis are improved. Whether the whole vehicle insulation is in-package insulation or out-package insulation can be directly distinguished, the troubleshooting time is shortened, safety throwing caused by insulation faults is reduced, and a client can be notified to carry out inspection in advance through early warning.

Description

Technical Field

[0001] The present invention relates to the fields of new energy vehicle safety monitoring and electric vehicle high-voltage safety, and in particular to a new energy vehicle insulation early warning method and system. Background Art

[0002] With the rapid development of the new energy electric vehicle industry, voltage levels are rising, from the initial 400V level to 800V and even 1000V. Good insulation performance is essential for the stable operation of high-voltage systems. Insulation failure in high-voltage systems can cause electric shock, threatening the safety of drivers and passengers. More seriously, it can cause a short circuit, resulting in fire or explosion.

[0003] GB / T 18384.1-2015 stipulates that the BMS for on-board rechargeable energy storage systems must perform insulation testing on all components of the power battery system after integration. Currently, every new energy vehicle on the market monitors insulation. However, current solutions only test the insulation of the entire vehicle. The vehicle's high-voltage system includes not only the battery pack but also other high-voltage components such as the motor, electronic control, and charger. Insulation failures in these components can also lead to a decrease in insulation resistance.

[0004] Existing insulation detection methods will only report insulation faults when the insulation fails completely. Customers cannot be informed in advance that the vehicle's insulation performance is low, which brings a poor experience to customers' safety and convenience. In other words, a fault alarm will only be issued when the insulation fault occurs completely, and effective early warning detection and alarm cannot be performed. At the same time, it is impossible to distinguish whether the insulation fault occurs inside the battery pack or in other high-voltage components of the vehicle, which makes fault location difficult and increases maintenance costs and time. Summary of the Invention

[0005] The purpose of the present invention is to overcome the shortcomings of the existing technology and provide an insulation warning method and system for new energy vehicles, so as to achieve early insulation warning and directly distinguish whether it is a battery pack insulation fault or an insulation fault of other high-voltage components of the entire vehicle (referred to as external insulation), thereby improving the accuracy and efficiency of insulation fault diagnosis.

[0006] In order to achieve the above object, the technical solution adopted by the present invention is: a new energy vehicle insulation early warning method, comprising collecting battery voltage information and calculating an insulation value based on the voltage information;

[0007] Determine the current state of the vehicle and perform early warning control according to the early warning strategy corresponding to the state combined with the insulation value. The early warning strategy estimates the risk of future insulation failure based on the calculated insulation value and outputs a early warning alarm.

[0008] The charging status information of the vehicle is collected to divide the vehicle status into parking charging state and non-charging state, and early warning control is performed in the charging state and non-charging state respectively.

[0009] When in the charging state, the insulation value in the charging process is monitored and calculated. If it is detected that the insulation value R0 at the current moment is less than the insulation threshold R1, then the insulation value R2 at the previous moment or the insulation value R3 at the next moment of the current insulation value is obtained. When the insulation value R0 at the current moment has a downward trend compared with the insulation value R2 at the previous moment and the decline reaches the set proportion threshold, and the insulation value with the lowest value between the insulation value R0 at the current moment and the insulation value R2 at the previous moment is lower than the insulation resistance threshold, it is judged that there is an insulation fault risk and an early warning signal is issued at this time; or when the insulation value R3 at the next moment has a downward trend compared with the insulation value R0 at the current moment and the decline reaches the set proportion threshold, and the insulation value with the lowest value between the insulation value R0 at the current moment and the insulation value R3 at the next moment is lower than the insulation resistance threshold, it is judged that there is an insulation fault risk and an early warning signal is issued at this time.

[0010] When the car is not charging, the insulation value is monitored and calculated, and each monitored insulation value is compared with the insulation resistance threshold. If the insulation value obtained by monitoring and calculation is lower than the insulation resistance threshold for multiple consecutive times, it is judged that there is a risk of insulation failure and a warning signal is issued.

[0011] When the vehicle is not charging, the insulation value is monitored and calculated. If the insulation value calculated within the set time period meets the following conditions multiple times in a row: the insulation value is detected to be lower than the insulation threshold R1, and the insulation value of the latter moment is on a downward trend relative to the insulation value of the previous moment, and the proportion of the decline reaches the proportional threshold, it is judged that there is a risk of insulation failure and a warning signal is issued.

[0012] The insulation value at the current moment is calculated by collecting the vehicle's voltage data. The insulation value obtained by averaging the insulation value at the current moment and the insulation value within a period of time before the current moment is used as the insulation value after de-jittering and filtering for early warning control.

[0013] When it is determined that there is an insulation fault risk and an early warning signal is output, the status of the main positive relay and the main negative relay of the battery pack are collected, and the fault location corresponding to the current insulation warning is determined based on the status of the main positive relay and the main negative relay.

[0014] When an insulation fault risk is determined and a warning signal is output, if both the main positive relay and the main negative relay of the battery pack are in an open state, the insulation warning fault is determined to be located within the battery pack and an insulation warning risk alarm is issued;

[0015] When judging that there is an insulation fault risk and outputting a warning signal, if the main positive relay and the main negative relay of the battery pack are in the closed state, the main positive relay and the main negative relay are adjusted and controlled to be in the disconnected state, and then it is judged whether the insulation fault risk disappears. If it is judged that the insulation fault risk disappears after disconnecting the main positive relay and the main negative relay within the set time range, then the insulation warning fault is located outside the battery pack.

[0016] A new energy vehicle insulation warning system includes an acquisition module, a control module and a warning module;

[0017] The acquisition module is used to collect the voltage data of the vehicle to calculate the insulation value;

[0018] The output end of the acquisition module is connected to the control module, and the output end of the control module is connected to the early warning module;

[0019] The control module uses the early warning method described in claims 1-8 to perform insulation risk early warning and outputs an early warning signal through the early warning module.

[0020] The system further comprises a de-jitter filtering module, which is used to perform de-jitter filtering on the collected and calculated insulation value to obtain a filtered insulation value at the current moment and send the filtered insulation value to the control module.

[0021] The advantages of the present invention are: it can achieve early insulation warning and directly distinguish whether it is a battery pack insulation fault or an insulation fault in other high-voltage components of the vehicle (referred to as external insulation), thereby improving the accuracy and efficiency of insulation fault diagnosis. It can directly distinguish whether the insulation of the vehicle is internal insulation or external insulation, reducing the time for troubleshooting and reducing the number of abandoned vehicles due to insulation failures. Through early warning, customers can be notified in advance of the progress of the inspection. The present invention also has the following advantages:

[0022] 1. Accurately locate the source of the fault: Through independent insulation detection circuits and logical judgment, it can accurately distinguish between insulation faults inside the battery pack and insulation faults in other high-voltage components of the vehicle.

[0023] 2. Improve maintenance efficiency: identify the source of the fault, reduce the troubleshooting time of maintenance personnel, and reduce maintenance costs.

[0024] 3. Enhanced safety: Real-time monitoring of insulation status, timely warning, and avoidance of safety accidents caused by insulation failure. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The following is a brief description of the contents and symbols in the drawings of the present invention:

[0026] Figure 1 This is a flow chart of the insulation early warning method of the present invention. DETAILED DESCRIPTION

[0027] The specific implementation of the present invention will be further explained in detail below by describing the best embodiment with reference to the accompanying drawings.

[0028] Example 1:

[0029] In order to overcome the difficulties of existing insulation detection technology in troubleshooting and the inability to predict in advance, the present invention provides an optimized early warning detection algorithm, thereby achieving early insulation warning and directly distinguishing whether it is a battery pack insulation fault or an insulation fault in other high-voltage components of the vehicle (referred to as external insulation), thereby improving the accuracy and efficiency of insulation fault diagnosis. Before an obvious insulation fault occurs, this solution uses insulation value data to conduct risk assessment, and judges whether an insulation fault will occur in the future time period according to the change in insulation value, thereby providing early warning for future insulation, improving the reliability of the warning, and achieving the purpose of early warning. At the same time, it can also locate the location of the warning fault during the insulation warning, and judge whether the insulation warning fault occurs inside or outside the pack. The specific solution is introduced as follows:

[0030] A new energy vehicle insulation warning method in this embodiment includes collecting battery voltage information and calculating an insulation value based on the voltage information;

[0031] Determine the current state of the vehicle and perform early warning control according to the early warning strategy corresponding to the state combined with the insulation value. The early warning strategy estimates the risk of future insulation failure based on the calculated insulation value and outputs a early warning alarm.

[0032] Collecting battery voltage information to calculate insulation values ​​involves collecting the battery's positive-to-ground voltage, negative-to-ground voltage, and reference resistance, and calculating the insulation resistance using the voltage divider principle. The insulation value, or insulation resistance value, is periodically calculated to determine whether there is an insulation failure risk. Based on this determination, an insulation warning is issued. The calculated insulation resistance value is called the calculated insulation value. Because insulation value collection is subject to various interference factors (such as electromagnetic interference and sensor noise), this value can fluctuate or jitter. To prevent inaccurate insulation values ​​at the current moment due to interference, this solution performs debounce filtering on the calculated insulation value. Debounce filtering involves calculating the current calculated insulation value and then averaging the current calculated insulation value with the insulation value from a period of time immediately before the current moment. This debounced and filtered value is used as the insulation value for early warning control. This average insulation value is the current insulation value. Using the current insulation value calculation method, insulation values ​​can be calculated at each moment. The calculated insulation value serves as the basis for subsequent insulation warnings.

[0033] This solution designs different early warning detection strategies according to the different states of the vehicle. It collects the vehicle's charging status information and divides the vehicle's state into parking charging state and non-charging state, and performs early warning control in the charging state and non-charging state respectively. Different insulation identification and early warning strategies are implemented according to the vehicle's charging state and non-charging state, specifically including:

[0034] While charging:

[0035] Monitor and calculate the insulation value during the charging process. If the current insulation value R0 is detected to be less than the insulation threshold R1, then obtain the insulation value R2 at the previous moment or the insulation value R3 at the next moment. If the current insulation value R0 shows a downward trend compared to the insulation value R2 at the previous moment and the decrease reaches the set proportion threshold, and the lowest insulation value between the current insulation value R0 and the previous insulation value R2 is lower than the insulation resistance threshold, then it is determined that there is an insulation failure risk and a warning signal is issued.

[0036] Alternatively, if the insulation value R3 at the next moment shows a downward trend compared to the insulation value R0 at the current moment, and the decrease reaches a set percentage threshold, and the lowest insulation value between the current insulation value R0 and the next insulation value R3 is lower than the insulation resistance threshold, then an insulation fault risk is determined and a warning signal is issued. If the insulation threshold R1 is greater than the insulation resistance threshold R but lower than the standard normal insulation resistance threshold, an insulation fault alarm will not be triggered. However, if it is lower than the normal insulation resistance, an insulation fault may occur in the future, necessitating a warning. The core of the warning judgment is to determine whether there is a downward trend in the insulation value between the two frames of insulation values ​​at the previous and next moments based on the current insulation value. If a downward trend in the insulation value is observed and the decrease exceeds approximately 50%, and one of the insulation values ​​is lower than the insulation resistance threshold, it can be determined that the vehicle is at risk of insulation fault in the future. Therefore, an insulation warning is issued, alerting the vehicle's insulation.

[0037] When the vehicle is not charging and any of the following conditions are met, an insulation warning is issued:

[0038] Condition 1: Monitor and calculate the insulation value, comparing each monitored insulation value with the insulation resistance threshold. If the insulation value obtained by monitoring and calculation is lower than the insulation resistance threshold multiple times in a row, it is determined that there is an insulation fault risk and an early warning signal is issued. If it is lower than the insulation resistance threshold multiple times, it indicates that this is not noise and is not an accidental situation, so it can be determined that there is an insulation risk.

[0039] Condition 2: Monitors calculated insulation values. If the calculated insulation values ​​repeatedly meet the following conditions within a set time period: the insulation value is detected to be below insulation threshold R1, and the subsequent insulation value calculated between two consecutive times is on a downward trend relative to the previous value, and the percentage of the decrease reaches the proportional threshold, then an insulation fault risk is determined and an early warning signal is issued. A 24-hour or 48-hour time period is set, and the difference between any two consecutive insulation value frames and their trend are calculated. If there is a downward trend with a drop of more than 50% for three consecutive times, this also indicates a risk and triggers an early warning.

[0040] When an insulation risk is identified, an early warning alarm signal is issued through the on-board instrumentation to provide a reminder. In order to further determine whether the insulation risk is located inside or outside the package during the reminder, this solution includes:

[0041] When it is determined that there is an insulation fault risk and an early warning signal is output, the status of the main positive relay and the main negative relay of the battery pack are collected, and the fault location corresponding to the current insulation warning is determined based on the status of the main positive relay and the main negative relay.

[0042] When an insulation fault risk is determined and a warning signal is output, if both the main positive relay and the main negative relay of the battery pack are in an open state, the insulation warning fault is determined to be located within the battery pack and an insulation warning risk alarm is issued;

[0043] When judging that there is an insulation fault risk and outputting a warning signal, if the main positive relay and the main negative relay of the battery pack are in the closed state, the main positive relay and the main negative relay are adjusted and controlled to be in the disconnected state, and then it is judged whether the insulation fault risk disappears. If it is judged that the insulation fault risk disappears after disconnecting the main positive relay and the main negative relay within the set time range, then the insulation warning fault is located outside the battery pack.

[0044] Through the above strategies and threshold calibration, it is possible to directly distinguish whether the vehicle insulation is inside the package or outside the package, reducing the troubleshooting time and reducing the abandonment caused by insulation failure. Through early warning, customers can be notified in advance of the progress inspection.

[0045] This embodiment also provides a new energy vehicle insulation warning system, including an acquisition module, a control module, a warning module, and a debounce filtering module;

[0046] The acquisition module is used to collect the voltage data of the vehicle to calculate the insulation value; the de-jitter filtering module is used to de-jitter and filter the collected and calculated insulation value to obtain the filtered insulation value at the current moment and send it to the control module.

[0047] The output end of the acquisition module is connected to the control module, and the output end of the control module is connected to the early warning module;

[0048] The control module uses the early warning method in the above embodiment to perform insulation risk early warning and outputs an early warning signal through the early warning module. The control module uses the BMS controller or VCU controller in the vehicle, which runs the early warning method in this embodiment to realize insulation early warning control.

[0049] Example 2:

[0050] The present invention provides an electric vehicle insulation warning system, comprising a data acquisition module, a data processing module, and a warning module. The data acquisition module includes a high-voltage insulation detection module, the data processing module includes BMS software for real-time vehicle data collection, and the warning module (VCU) is used to issue warnings to the vehicle, driver, or app, prompting the customer or after-sales service station to invite the customer to the station for vehicle inspection.

[0051] The data acquisition module collects the battery's positive-to-ground voltage, negative-to-ground voltage, and reference resistance, and calculates the insulation resistance using the principle of voltage division. This high-voltage insulation calculation information is then transmitted to the data processing module, which receives the insulation resistance value and collects information such as the vehicle's charging status, insulation value, and relay status. The module then processes the data and transmits the warning results and the results of the internal and external insulation differentiation to the warning module. Based on the warning results, the warning module illuminates a light on the vehicle's instrument panel to remind the customer to enter the station for maintenance.

[0052] The present invention includes a data acquisition module, a data processing module, and an early warning module. The BMS (battery management system) collects vehicle parameters in real time and performs low-frequency analysis to extract characteristic parameters. The steps are as follows:

[0053] 1. Early Warning

[0054] 1. Determine whether the vehicle is in a discharging or charging state:

[0055] If the vehicle is running in the non-parking charging and non-charging completed state:

[0056] ·Criterion 1: In the insulation monitoring system of electric vehicles, the collection of insulation values ​​will be subject to various interferences (such as electromagnetic interference, sensor noise, etc.), causing the insulation values ​​to jitter or fluctuate. A single threshold value will lead to false alarms of early warnings. In order to improve the accuracy and reliability of insulation monitoring, the BMS software performs de-jitter processing on the collected insulation values, that is, by calculating the average value of the insulation value over a period of time to eliminate instantaneous fluctuations. The method is as follows: first set a sliding window of fixed length (such as 10 sampling points), and then each time a new insulation value is collected, add it to the window, remove the earliest value, and calculate the average value of all data in the window as the current filtered insulation value. If the insulation resistance value is lower than the dynamically calculated insulation resistance low threshold R1, and it is established for 10 consecutive times, an early warning is triggered. (The insulation threshold is dynamically adjusted according to the vehicle model and safety standards)

[0057] Criterion 2: If the insulation resistance falls below 9000KΩ and the insulation resistance between two frames of data drops by more than 50% for three consecutive times within 48 hours, an alert is triggered. (The insulation threshold is dynamically adjusted based on vehicle model and safety standards.)

[0058] 2. If the vehicle is in the parking charging state: During a charging process, after the insulation value is debounced, the insulation value is lower than 9000KΩ, and the insulation value drops by 50% between two frames, and the lowest insulation value is lower than the insulation resistance threshold, the insulation resistance is too low warning is marked;

[0059] 2. Differentiate between battery pack batteries or other high-voltage components outside the pack

[0060] Distinguish whether the battery pack is internally insulated or externally insulated: If the main positive and negative relays of the battery pack are not closed, it means that the high voltage state is not in place. At this time, condition 1 or condition 2 is met, and a battery pack insulation warning is issued; if the main positive and negative relays are closed, then condition 1 or condition 2 is met. If the main positive and negative relays are disconnected, then condition 1 or condition 2 is not met, and an external insulation warning is issued. (You can understand this by referring to the high voltage schematic diagram in the attached figure)

[0061] Through the above strategies and threshold calibration, it is possible to directly distinguish whether the vehicle insulation is inside the package or outside the package, reducing the troubleshooting time and reducing the abandonment caused by insulation failure. Through early warning, customers can be notified in advance of the progress inspection.

[0062] A method and system for electric vehicle insulation warning uses an independent insulation detection circuit within the power battery pack to measure the insulation resistance between the positive and negative electrodes of the battery pack and the battery pack casing in real time. Combined with the battery management system (BMS) and vehicle control unit (VCU), this system can accurately distinguish insulation faults within the battery pack from insulation faults in other high-voltage components of the vehicle, and issue a corresponding warning signal based on the insulation warning judgment result. The steps are as follows:

[0063] 1. The acquisition module sets up an independent insulation detection circuit inside the power battery pack to detect the insulation resistance value information and reference resistance value of the battery pack positive and negative poles to the battery pack shell in real time. The BMS hardware also collects information such as vehicle charging status, insulation value, and relay status in real time;

[0064] 2. The BMS central processor first calculates the insulation resistance using the voltage division principle and performs insulation value debounce processing to obtain the real and effective insulation value for subsequent judgment.

[0065] 3. Comprehensively judge the vehicle insulation risk based on the actual insulation value, vehicle charging status, relay status and other information (see the invention content for details)

[0066] 4. According to the high-voltage schematic, when the positive and negative relays of the battery pack are disconnected, the battery pack insulation detection circuit is disconnected from other high-voltage components of the vehicle, and the insulation of the battery pack itself is detected. Then, by judging 1 and 2 in the invention content, it is possible to accurately distinguish between internal insulation faults in the battery pack and insulation faults in other high-voltage components of the vehicle.

[0067] 5. Based on the insulation warning results, the BMS or vehicle control unit (VCU) issues a corresponding warning signal. For example, the instrument prompts: "Insulation fault, please check the high-voltage system." The mobile app reminds: "Schedule maintenance" provides customers with a one-click maintenance reservation service, streamlining the process.

[0068] Obviously, the specific implementation of the present invention is not limited to the above-mentioned methods. As long as various non-substantial improvements are made using the method concept and technical solution of the present invention, they are all within the scope of protection of the present invention.

Claims

1. A new energy vehicle insulation early warning method, characterized by: Including collecting battery voltage information and calculating insulation value based on the voltage information; Determine the current state of the vehicle and perform early warning control according to the early warning strategy corresponding to the state combined with the insulation value. The early warning strategy estimates the risk of future insulation failure based on the calculated insulation value and outputs a early warning alarm.

2. A new energy vehicle insulation early warning method according to claim 1, characterized in that: The charging status information of the vehicle is collected to divide the vehicle status into parking charging state and non-charging state, and early warning control is performed in the charging state and non-charging state respectively.

3. A new energy vehicle insulation early warning method according to claim 2, characterized in that: When in the charging state, the insulation value in the charging process is monitored and calculated. If it is detected that the insulation value R0 at the current moment is less than the insulation threshold R1, then the insulation value R2 at the previous moment or the insulation value R3 at the next moment of the current insulation value is obtained. When the insulation value R0 at the current moment has a downward trend compared with the insulation value R2 at the previous moment and the decline reaches the set proportion threshold, and the insulation value with the lowest value between the insulation value R0 at the current moment and the insulation value R2 at the previous moment is lower than the insulation resistance threshold, it is judged that there is an insulation fault risk and an early warning signal is issued at this time; or when the insulation value R3 at the next moment has a downward trend compared with the insulation value R0 at the current moment and the decline reaches the set proportion threshold, and the insulation value with the lowest value between the insulation value R0 at the current moment and the insulation value R3 at the next moment is lower than the insulation resistance threshold, it is judged that there is an insulation fault risk and an early warning signal is issued at this time.

4. The insulation early warning method for new energy vehicles according to claim 2, characterized in that: When the car is not charging, the insulation value is monitored and calculated, and each monitored insulation value is compared with the insulation resistance threshold. If the insulation value obtained by monitoring and calculation is lower than the insulation resistance threshold for multiple consecutive times, it is judged that there is a risk of insulation failure and a warning signal is issued.

5. A new energy vehicle insulation early warning method according to claim 2 or 4, characterized in that: When the vehicle is not charging, the insulation value is monitored and calculated. If the insulation value calculated within the set time period meets the following conditions multiple times in a row: the insulation value is detected to be lower than the insulation threshold R1, and the insulation value of the latter moment is on a downward trend relative to the insulation value of the previous moment, and the proportion of the decline reaches the proportional threshold, it is judged that there is a risk of insulation failure and a warning signal is issued.

6. A new energy vehicle insulation early warning method according to any one of claims 1 to 5, characterized in that: The insulation value at the current moment is calculated by collecting the vehicle's voltage data. The insulation value obtained by averaging the insulation value at the current moment and the insulation value within a period of time before the current moment is used as the insulation value after de-jittering and filtering for early warning control.

7. A new energy vehicle insulation early warning method according to any one of claims 1 to 5, characterized in that: When it is determined that there is an insulation fault risk and an early warning signal is output, the status of the main positive relay and the main negative relay of the battery pack are collected, and the fault location corresponding to the current insulation warning is determined based on the status of the main positive relay and the main negative relay.

8. The insulation early warning method for new energy vehicles according to claim 7, characterized in that: When an insulation fault risk is determined and a warning signal is output, if both the main positive relay and the main negative relay of the battery pack are in an open state, the insulation warning fault is determined to be located within the battery pack and an insulation warning risk alarm is issued; When judging that there is an insulation fault risk and outputting a warning signal, if the main positive relay and the main negative relay of the battery pack are in the closed state, the main positive relay and the main negative relay are adjusted and controlled to be in the disconnected state, and then it is judged whether the insulation fault risk disappears. If it is judged that the insulation fault risk disappears after disconnecting the main positive relay and the main negative relay within the set time range, then the insulation warning fault is located outside the battery pack.

9. A new energy vehicle insulation warning system, characterized by: Including acquisition module, control module and early warning module; The acquisition module is used to collect the voltage data of the vehicle and calculate the insulation value based on the collected voltage data; The output end of the acquisition module is connected to the control module, and the output end of the control module is connected to the early warning module; The control module uses the early warning method described in claims 1-8 to perform insulation risk early warning and outputs an early warning signal through the early warning module.

10. The insulation warning system for new energy vehicles according to claim 9, characterized in that: The system further comprises a de-jitter filtering module, which is used to perform de-jitter filtering on the collected and calculated insulation value to obtain a filtered insulation value at the current moment and send the filtered insulation value to the control module.

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