Fault diagnosis method and system for low meter display SOC of vehicle-mounted power battery
By using multi-dimensional data analysis and the OCV-SOC curve algorithm, the SOC deviation of the vehicle power battery can be diagnosed in real time, solving the problem of low displayed SOC and improving the accuracy of SOC estimation and user experience.
Patent Information
- Application Number
- CN202511757365.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-11-27
- Publication Date
- 2026-02-27
AI Technical Summary
In existing technologies, the SOC estimation of vehicle power batteries is inaccurate, especially the displayed SOC is too low, which leads to problems such as shortened driving range, inappropriate charging strategies, degraded vehicle performance, and decreased user trust.
Through multi-dimensional data analysis and model prediction, the charging and discharging current, single-cell module voltage and battery temperature data of the power battery are collected in real time. The actual SOC is calculated using the OCV-SOC curve algorithm and compared with the displayed SOC to diagnose SOC deviation. Thresholds and durations are set to determine low SOC faults.
It improves the accuracy of SOC estimation, reduces the risk of an underestimation of SOC, ensures users receive accurate remaining battery information, and enhances the vehicle's user experience and safety.
Smart Images
Figure CN121572852A_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The present application relates to a fault diagnosis method and system for low displayed SOC of a vehicle-mounted power battery, belonging to the technical field of new energy vehicles. BACKGROUND
[0002] With the popularization of new energy vehicles, the SOC (State of Charge) of the power battery is an important indicator for measuring the remaining battery capacity. However, due to the error or failure of the battery management system (BMS), the displayed SOC may deviate from the actual SOC, especially when the displayed SOC is low, which may cause the following problems in the vehicle: Shortened range: a low displayed SOC will mislead the driver about the remaining battery capacity, affecting the vehicle's range, and may cause the vehicle to suddenly lose power during driving, affecting road safety.
[0003] Improper charging strategy: a low displayed SOC may cause the driver to charge frequently, increasing the number of charges and affecting the charging efficiency and life of the battery.
[0004] Decline in vehicle performance: a low displayed SOC may limit the output power of the vehicle's power system, affecting the vehicle's acceleration performance and climbing ability.
[0005] User trust decreases: a low displayed SOC will affect users' trust in the vehicle's battery management system, reducing user experience.
[0006] In summary, in the prior art, the SOC estimation of the vehicle-mounted power battery is mainly based on voltage, current and temperature parameters, but due to battery aging, environmental temperature changes, charge / discharge history and other factors, the SOC estimation may be biased. A low displayed SOC will mislead users about the remaining capacity, affecting the vehicle's use experience and battery life. SUMMARY
[0007] The purpose of the present application is to overcome the shortcomings of the prior art and provide a fault diagnosis method and system for low displayed SOC of a vehicle-mounted power battery, which accurately identifies the fault of low displayed SOC through multi-dimensional data analysis and model prediction, improving the reliability of the battery management system. To achieve the above-mentioned purpose / To solve the above-mentioned technical problems, the present application is realized by the following technical scheme: A fault diagnosis method for low displayed SOC of a vehicle-mounted power battery, the method comprising: Real-time acquisition of charge / discharge current, displayed SOC, single module voltage and battery temperature data of the power battery; According to the collected single module voltage, charge and discharge current and temperature data, the actual SOC of the system single module is calculated by using the calibrated OCV-SOC curve algorithm, and compared with the indicated SOC, and the SOC deviation is calculated. According to the size and duration of the SOC deviation, the fault of the indicated SOC being too low is diagnosed.
[0008] In the above technical solution, through multi-dimensional data fusion and intelligent algorithm, the accuracy of SOC estimation is significantly improved, the risk of indicated SOC being too low is reduced, and the accuracy of SOC estimation is improved.
[0009] Optionally, according to the size and duration of the SOC deviation, the fault of the indicated SOC being too low includes: If the SOC deviation lasts more than a preset threshold and the duration exceeds a preset time, it is determined that the indicated SOC is too low.
[0010] In the above technical solution: through the determination basis, the fault caused by the jump of the indicated SOC can be effectively filtered out.
[0011] Optionally, according to the size and duration of the SOC deviation, the fault of the indicated SOC being too low also includes: If the SOC deviation fluctuates greatly within a preset time and is inconsistent with the change trend of the battery temperature and the charge and discharge current, it is determined that the indicated SOC is too low.
[0012] In the above technical solution: by combining the change trend of the battery temperature and the current, the accuracy of determining the fault of the indicated SOC being too low is increased.
[0013] Optionally, the calculation of the SOC deviation includes: According to the OCV-SOC curve and the single string battery voltage value obtained in the parking and standing stage, the state of charge of the vehicle-mounted power battery is calculated, and the SOC calculated according to the average voltage of each string voltage is the average state of charge of the battery system, ; Actual state of charge The formula is: ; Wherein, The SOC value calculated for each single voltage, n is the total number of single batteries, Indicates the actual state of charge of the vehicle, The average state of charge; The difference between the actual state of charge of the battery system and the indicated SOC is calculated; ; Wherein, The error between the actual and indicated state of charge, calculating for a vehicle battery management system, for a vehicle actual state of charge.
[0014] In the above technical solution: based on the calculation logic, the actual remaining SOC of the vehicle can be accurately calculated and evaluated. By comparing and analyzing the difference in numerical value between the actual remaining SOC of the vehicle and the indicated SOC, it is evaluated whether there is an indicated SOC fault of low value.
[0015] Optionally, the fault of low value of the indicated SOC according to the size and duration of the SOC deviation includes: The error of the remaining state of charge of the vehicle is used to divide the fault level, and the fault of the power battery of the vehicle is diagnosed. When the error of the remaining state of charge of the vehicle is greater than a first preset value and less than a second preset value, it is level one; when the error of the remaining state of charge of the vehicle is greater than the second preset value and less than a third preset value, it is level two; and when the error of the remaining state of charge of the vehicle is greater than or equal to the third preset value, it is level three.
[0016] In the above technical solution: by analyzing the difference in numerical value between the actual remaining SOC of the vehicle and the indicated SOC, setting an error threshold, the fault degree of low SOC can be standardized and quantified, and the fault level can be divided.
[0017] Optionally, the method further includes: The fault of low value of the indicated SOC is diagnosed and an alarm prompt is sent to the user end through the vehicle display screen or the mobile phone APP, and the user end is suggested to charge in time or contact the after-sales service.
[0018] In the above technical solution: the alarm strategy can quickly respond to the fault, timely inform the driver, and avoid the risk of low power of the vehicle.
[0019] Optionally, the method further includes: storing the fault diagnosis result and the battery data to the cloud for analyzing and optimizing the battery management system.
[0020] In the above technical solution: through data cloud storage, potential fault vehicles can be recorded to some extent, which is convenient for management and tracking of risk fault vehicles in the later stage.
[0021] Second aspect: a fault diagnosis system for the indicated SOC of the vehicle power battery being low, the system includes: A data acquisition module is configured to acquire the charging and discharging current, the indicated SOC, the single module voltage and the battery temperature data of the power battery in real time. An SOC deviation calculation module is configured to calculate the actual SOC of the single module of the system according to the acquired single module voltage, charging and discharging current and temperature data, and compare the actual SOC with the indicated SOC to calculate the SOC deviation. A fault diagnosis module is configured to diagnose a fault of a low indicated SOC according to the size and duration of the SOC deviation.
[0022] Optionally, the system further comprises: A fault alarm module is configured to alarm the user end through a vehicle-mounted display screen or a mobile phone APP, and suggest the user end to charge in time or contact after-sales service.
[0023] In the above technical solution, the alarm strategy can quickly respond to the fault, timely inform the user end, and avoid the risk of low battery level.
[0024] Optionally, the system further comprises: A data storage and analysis module is configured to store the fault diagnosis result and the battery data to the cloud for analyzing and optimizing the battery management system.
[0025] In the above technical solution, through the data cloud storage, the potential fault vehicle can be recorded to some extent, which facilitates the management and tracking of the risk fault vehicle in the later stage.
[0026] Compared with the prior art, the present application has the following advantages: The present application significantly improves the accuracy of SOC estimation through multi-dimensional data fusion and intelligent algorithm, reduces the risk of low indicated SOC, and improves the accuracy of SOC estimation. The present application monitors the deviation between the indicated SOC and the actual SOC in real time, obtains the remaining power in time, and realizes the omnidirectional real-time monitoring of the vehicle state. The present application can accurately identify the fault of low indicated SOC through multi-dimensional data analysis and model prediction, improve the reliability of the battery management system, avoid the problems of reduced range, improper charging strategy, and reduced vehicle performance caused by low indicated SOC, and improve the user experience and driving safety. BRIEF DESCRIPTION OF DRAWINGS
[0027] Figure 1 The figure shows the flowchart of the fault diagnosis method of the vehicle-mounted power battery with low indicated SOC. DETAILED DESCRIPTION
[0028] In order to make the technical means, creative features, purposes and effects of the present application easy to understand, the present application is further described below in combination with specific embodiments.
[0029] In the description of the present application, it needs to be understood that the terms "center", "longitudinal", "transverse", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application. In addition, the terms "first", "second" and the like are only for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined with "first", "second" and the like can explicitly or implicitly include one or more of the features. In the description of the present application, unless otherwise specified, the meaning of "a plurality of" is two or more.
[0030] In the description of the present application, it needs to be explained that, unless otherwise explicitly specified and limited, the terms "mounting", "connection", "connection" should be understood broadly, for example, it can be fixed connection, or detachable connection, or integral connection; it can be mechanical connection, or electrical connection; it can be directly connected, or indirectly connected through intermediate medium, it can be the communication inside two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood through specific circumstances.
[0031] In addition, in order to facilitate a deeper understanding of the present application, the following explains several key terms involved therein as follows: 1、SOC estimated value: this technology estimates the actual state of charge of the power battery pack by estimating the state of charge of the lowest voltage battery monomer. This index reflects the power level of the battery pack in actual use, and is an important basis for evaluating battery performance and remaining endurance.
[0032] 2、Apparent SOC definition: the state of charge (SOC) value calculated by the vehicle BMS (battery management system) and displayed on the vehicle instrument panel. This value aims to visually display the remaining battery capacity to the driver, and is usually calibrated and optimized by the system to reflect the actual available capacity of the battery.
[0033] 3. OCV-SOC Curve: Battery Open Circuit Voltage (OCV). For each set SOC state, the OCV value is measured under the corresponding temperature conditions. Based on the voltage plateau characteristics of lithium iron phosphate batteries, SOC test points are reasonably set, including but not limited to the following 35 key SOC states: 100%, 99%, 98%, 95%, 85%, 75%, 65%, 63%, 61%, 59%, 57%, 55%, 45%, 35%, 30%, 28%, 26%, 24%, 22%, 20%, 18%, 16%, 14%, 12%, 10%, 9%, 8%, 7%, 6%, 5%, 4%, 3%, 2%, 1%, 0%.
[0034] like Figure 1 As shown, this invention discloses a fault diagnosis method for a vehicle power battery with a low displayed SOC, the method comprising: Step 1: Real-time acquisition of charging and discharging current, displayed SOC, single-cell module voltage, and battery temperature data of the power battery; Step 2: Based on the collected data of individual module voltage, charging and discharging current and temperature, the calibrated OCV-SOC curve algorithm is used to calculate the actual SOC of the system's individual modules and compare it with the displayed SOC to calculate the SOC deviation; through this judgment criterion, faults caused by the display SOC jump can be effectively filtered out. Step 3: Based on the magnitude and duration of the SOC deviation, diagnose the fault of low displayed SOC. In this embodiment, step 2 determines whether a fault exists where the displayed SOC is too low based on the magnitude and duration of the SOC deviation. The specific steps are as follows: ① If the SOC deviation continues to exceed the preset threshold (e.g., 10%) and the duration exceeds the preset time (e.g., 60 minutes), it is determined to be a low SOC fault.
[0035] ② If the SOC deviation fluctuates significantly in a short period of time and is inconsistent with the changing trends of parameters such as battery temperature and current, it is determined to be a fault of low displayed SOC.
[0036] The above technical solution, through multi-dimensional data fusion and intelligent algorithms, significantly improves the accuracy of SOC estimation, reduces the risk of underestimating SOC, and enhances the accuracy of SOC estimation.
[0037] In this embodiment, in step 3, SOC deviation calculation: using the calibrated OCV-SOC curve method, based on the battery's voltage, current, and temperature data, the actual SOC of the battery is calculated and compared with the displayed SOC to calculate the SOC deviation.
[0038] The state of charge of the vehicle-mounted power battery is calculated according to the OCV-SOC curve and all single-battery voltage values obtained in the parking standby stage, and the average voltage of each string voltage is calculated to obtain the average state of charge of the battery system, denoted as .
[0039] ; wherein, is the SOC value calculated for each single-battery voltage, and n is the total number of single batteries.
[0040] Actual state of charge which can be expressed by the following formula: ; wherein, represents the state of charge of the i-th battery monomer in the series battery pack, and n is the total number of single batteries. The min function represents the minimum value of all single SOC in the series battery pack.
[0041] In the above technical solution: based on the calculation logic, the actual remaining SOC of the vehicle can be accurately calculated and evaluated, and by comparing and analyzing the difference in numerical value between the actual remaining SOC and the indicated SOC, it can be evaluated whether there is a fault of low indicated SOC.
[0042] By calculating the difference between the actual state of charge and the indicated SOC of the battery system, and threshold dividing the size of the difference, the fault level of the indicated SOC of the battery pack can be evaluated.
[0043] ; wherein is the error between the actual and indicated state of charge, is calculated by the vehicle BMS (battery management system), is the minimum state of charge, i.e. the actual state of charge of the vehicle.
[0044] In this embodiment, whether there is a fault of low indicated SOC is judged according to the size and duration of the SOC deviation. If the SOC deviation lasts more than a preset threshold and the duration exceeds a preset time, it is determined that there is a fault of low indicated SOC.
[0045] By the error size of the remaining state of charge of the vehicle, the fault level is divided, and the fault diagnosis of the power battery of the vehicle is carried out. When 10% <15%, it is level 1; when 15% <20%, it is level 2; and when ≥20%, it is level 3.
[0046] In the technical solution, by analyzing the difference between the actual residual SOC and the indicated SOC in value, an error threshold is set, which can standardize and quantify the fault degree of the low SOC, and divide the fault level.
[0047] In the specific implementation of the embodiment, when the indicated SOC low fault is detected, an alarm prompt is sent to the driver through the vehicle display screen or the mobile phone APP, and the driver is advised to charge in time or contact the after-sales service.
[0048] The fault information is first stored locally and then uploaded to the cloud platform through the Internet, and according to the identified fault type and fault level, an alarm is sent in time (the fault type and fault level need to be distinguished by using a state code). After the fault information is uploaded, the corresponding alarm mechanism is triggered according to the specific fault type. In order to distinguish different fault types and fault levels, the state code is used to encode and identify the fault. The specific encoding rules are as follows: The state code of the first-level fault is 00000010, the state code of the second-level fault is 00000100, and the state code of the third-level fault is 00001000.
[0049] In the specific implementation of the embodiment, the fault diagnosis result and the related battery data are stored to the cloud, which is convenient for subsequent analysis and optimization of the algorithm of the battery management system.
[0050] The present application can accurately estimate the SOC, avoid over-discharge or over-charge of the battery, and prolong the service life of the battery. By ensuring that the user obtains accurate remaining power information, the use experience of the vehicle and the user trust are improved.
[0051] The indicated SOC is automatically corrected, manual intervention is reduced, and the intelligent level of the system is improved. Based on the working mechanism of the battery, the vehicle key stage is monitored and captured, the key indicators of the battery performance change are analyzed in a targeted and timely manner, the fault is judged in advance, the fault reason and specific position are determined, the rapid response and intervention are realized, the timeliness and accuracy of fault identification are ensured, the occurrence of hidden troubles is avoided, and the reliability and safety are improved.
[0052] Embodiment 2 discloses a fault diagnosis system for the indicated SOC of the vehicle-mounted power battery being low, and the system comprises: A data acquisition module is configured to acquire the charge and discharge current, the indicated SOC, the single module voltage and the battery temperature data of the power battery in real time. An SOC deviation calculation module is configured to calculate the actual SOC of the single module of the system according to the acquired single module voltage, charge and discharge current and temperature data, compare the actual SOC with the indicated SOC, and calculate the SOC deviation by using a calibrated OCV-SOC curve algorithm. A fault diagnosis module is configured to diagnose a fault of a low indicated SOC according to the size and duration of the SOC deviation; A fault alarm module is configured to alarm the driver through a vehicle display screen or a mobile phone APP and suggest the driver to charge in time or contact after-sales service.
[0053] A data storage and analysis module is configured to store the fault diagnosis result and the battery data to the cloud for analyzing and optimizing the battery management system. In this embodiment, the alarm strategy can quickly respond to the fault, timely inform the driver, and avoid the risk of low battery power.
[0054] An automatic correction module is configured to automatically correct the indicated SOC according to the actual SOC, so as to ensure that the user obtains accurate remaining power information.
[0055] In this embodiment, the data cloud storage can record potential fault vehicles to some extent, which is convenient for the management and tracking of the risk fault vehicles in the later stage.
[0056] The above only describes the preferred embodiments of the present application. It should be noted that those skilled in the art can make several improvements and modifications without departing from the technical principles of the present application. These improvements and modifications should also be considered as the protection scope of the present application.
Claims
1. A fault diagnosis method for a low displayed SOC of a vehicle-mounted power battery, characterized in that, The method comprises: Real-time acquisition of charge-discharge current, apparent SOC, single module voltage and battery temperature data of the power battery; According to the collected single module voltage, charge-discharge current and temperature data, the actual SOC of the system single module is calculated by using the calibrated OCV-SOC curve algorithm, and compared with the apparent SOC to calculate the SOC deviation; According to the size and duration of the SOC deviation, the fault of the low apparent SOC is diagnosed.
2. The method for diagnosing the fault of the low indicated SOC of the on-board power battery according to claim 1, characterized in that, The fault of the low apparent SOC is diagnosed according to the size and duration of the SOC deviation, comprising: If the SOC deviation lasts more than a preset threshold and the duration exceeds a preset time, it is determined that the apparent SOC is low.
3. The method for diagnosing the fault of the low indicated SOC of the on-board power battery according to claim 1, characterized in that, The fault of the low apparent SOC is diagnosed according to the size and duration of the SOC deviation, further comprising: If the SOC deviation fluctuates greatly within a preset time and is inconsistent with the change trend of the battery temperature and the charge-discharge current, it is determined that the apparent SOC is low.
4. The method for diagnosing the fault of the low indicated SOC of the on-board power battery according to claim 1, characterized in that, The SOC deviation is calculated, comprising: According to the OCV-SOC curve and the single string battery voltage value obtained in the parking and standing stage, the state of charge of the vehicle-mounted power battery is calculated, and the SOC calculated according to the average voltage of each string voltage is the average state of charge of the battery system, ； actual state of charge The formula is: ; wherein, SOC value calculated for each monomer voltage, n is the total number of monomer cells, denotes the actual state of charge of the vehicle, is the average state of charge; by calculating the difference between the actual state of charge of the battery system and the apparent SOC; ; wherein, is the actual and indicated state of charge error, is calculated by the vehicle battery management system, is the vehicle actual state of charge.
5. The method for diagnosing the fault of the low indicated SOC of the on-board power battery according to claim 1, characterized in that, The fault of the low apparent SOC is diagnosed according to the size and duration of the SOC deviation, comprising: The fault level is divided by the size of the remaining state of charge error of the vehicle, and the power battery of the vehicle is diagnosed, when the remaining state of charge error of the vehicle is greater than a first preset value and less than a second preset value, it is level one; when the remaining state of charge error of the vehicle is greater than the second preset value and less than a third preset value, it is level two; when the remaining state of charge error of the vehicle is greater than or equal to the third preset value, it is level three.
6. The method for diagnosing the fault of the low indicated SOC of the on-board power battery according to claim 1, characterized in that, The method further comprises: The fault of the low apparent SOC is diagnosed and an alarm prompt is sent to the user end through the vehicle-mounted display screen or the mobile phone APP, and the user end is suggested to charge in time or contact the after-sales service.
7. The method for diagnosing the fault of the low indicated SOC of the on-board power battery according to claim 1, characterized in that, The method further comprises: storing the fault diagnosis result and the battery data to the cloud analysis and battery management system.
8. A fault diagnosis system for a vehicle-mounted power battery apparent SOC lower, characterized in that, The system comprises: A data acquisition module for real-time acquisition of charge-discharge current, apparent SOC, single module voltage and battery temperature data of the power battery; An SOC deviation calculation module for calculating the actual SOC of the system single module by using the calibrated OCV-SOC curve algorithm according to the collected single module voltage, charge-discharge current and temperature data, and comparing with the apparent SOC to calculate the SOC deviation; A fault diagnosis module for diagnosing the fault of the low apparent SOC according to the size and duration of the SOC deviation.
9. The system for diagnosing a fault of a low indicated SOC of an on-board power battery according to claim 7, characterized in that, The system further comprises: A fault alarm module for sending an alarm prompt to the user end through the vehicle-mounted display screen or the mobile phone APP when the fault of the low apparent SOC is diagnosed, and suggesting the user end to charge in time or contact the after-sales service.
10. The system for diagnosing a fault of a low indicated SOC of an on-board power battery according to claim 7, characterized in that, The system further comprises: A data storage and analysis module for storing the fault diagnosis result and the battery data to the cloud analysis and optimization battery management system.