Battery state evaluation method based on vehicle data

Abstract

The invention provides a battery state evaluation method based on vehicle data. The method comprises the following steps: acquiring vehicle data in a required time period; evaluating battery states according to the vehicle data, wherein the battery states comprise the capacity state, the internal resistance state, the temperature state and the charging and discharging state of a battery; wherein the step of evaluating the capacity state of the battery comprises capacity health degree evaluation and capacity consistency evaluation, and the step of evaluating the internal resistance state of the battery comprises internal resistance health degree evaluation and internal resistance consistency evaluation; the evaluation of the temperature state of the battery comprises battery pack thermal abuse evaluation and temperature consistency evaluation; the step of evaluating the charging and discharging state of the battery comprises the sub-steps of evaluating the charging and discharging limitation of the battery pack, calculating the SOH of a plurality of battery cells according to the SOH of a single battery cell to obtain a relative difference value, and evaluating the charging and discharging limitation of the battery pack by setting a charging and discharging limitation evaluation threshold value. According to the invention, the battery is evaluated through multiple dimensions, so that the accuracy and reliability of battery evaluation are improved.

Description

Technical Field

[0001] The present invention relates to the technical field of vehicle battery monitoring, and more specifically, to a battery status evaluation method based on vehicle data. Background Art

[0002] As the market size of new energy vehicles continues to expand and the service life of new energy vehicles is relatively short, the health status of power batteries, as the "smart heart" of electric vehicles, directly determines whether electric vehicles can run normally. Automotive power batteries are affected by their own material system and manufacturing factors. As the vehicle ages, the health of the battery will decay to varying degrees. As the battery is gradually used, the self-discharge phenomenon may gradually increase, the inconsistency between the battery cells may gradually increase, and the consumption of the battery SOC will also increase, reducing the driving range. Even when the decay is severe or the vehicle has been in a certain degree of collision, it will also bring certain safety risks. In addition, how to accurately evaluate the battery status of used cars is a major problem that urgently needs to be further solved in the future.

[0003] At present, in the process of recycling used car batteries, the accumulated mileage of the vehicle is generally used to infer the remaining available capacity of the battery. This method is relatively simple to operate, but the disadvantage is that the error is large and it is impossible to know the exact remaining available capacity of the battery. When recycling used cars, some companies will use additional equipment to obtain the remaining available capacity of the battery. The advantage of this solution is that it can accurately obtain the current remaining available capacity of the battery. The disadvantage is that it not only consumes a lot of time, manpower and economic costs, but also cannot detect the battery status of vehicles in large quantities at the same time. In addition, this method can only obtain the current status of the battery, and cannot evaluate the stability of the long-term performance of the battery, so it is impossible to accurately predict the future life and performance degradation of the battery, which increases the uncertainty of the evaluation. Only considering the remaining available capacity of the vehicle battery cannot fully evaluate the health status of the battery. Summary of the invention

[0004] The present invention provides a battery status evaluation method based on vehicle data, aiming to solve the problem that it is difficult to evaluate the stability of the long-term performance of the battery and to improve the accuracy and reliability of the battery evaluation.

[0005] To achieve the above object, the present invention provides a battery status evaluation method based on vehicle data, comprising:

[0006] Obtain vehicle data for a required time period, the vehicle data including battery temperature data, current data, voltage data, charging time data, and mileage data during charging;

[0007] Evaluating the battery status according to the vehicle data, including evaluating the battery capacity status, internal resistance status, temperature status, and charge and discharge status;

[0008] The evaluation of the battery capacity status includes capacity health evaluation and capacity consistency evaluation. The capacity health evaluation calculates the SOH of the entire battery pack and the SOH of a single cell according to the charging time data, the mileage data during charging, and the current data. The capacity consistency evaluation calculates the standard deviation of the capacities of multiple cells according to the SOH of a single cell to evaluate the capacity consistency of the current vehicle.

[0009] The evaluation of the internal resistance state of the battery includes an internal resistance health evaluation and an internal resistance consistency evaluation. The internal resistance health evaluation calculates the internal resistance and internal resistance SOH of a single cell according to the temperature data, current data and voltage data of the battery; the internal resistance consistency evaluation calculates the standard deviation of the internal resistance of multiple cells according to the internal resistance of the single cell to evaluate the consistency of the internal resistance of the cell;

[0010] The evaluation of the temperature state of the battery includes battery pack thermal abuse evaluation and temperature consistency evaluation. The battery pack thermal abuse evaluation sets a temperature threshold for the temperature data of the single cell, screens the number of frames exceeding the temperature threshold, and calculates the frequency of exceeding the temperature threshold to evaluate the battery pack thermal abuse record; the temperature consistency evaluation sets a temperature difference threshold for the temperature data of the single cell, calculates the frequency of exceeding the temperature difference threshold, and evaluates the battery pack temperature consistency;

[0011] The evaluation of the battery charge and discharge status includes battery pack charge and discharge limit evaluation. According to the SOH of a single battery cell, the SOH of multiple batteries is calculated to obtain a relative difference. By setting a charge and discharge limit evaluation threshold, the battery pack charge and discharge limit is evaluated.

[0012] In one embodiment, the capacity health assessment specifically includes:

[0013] Based on the mileage data during charging, batch extract the data of all vehicles with the same mileage during charging;

[0014] Filter the mileage data during charging to select the charging segments that meet the requirements;

[0015] Calculate the battery pack SOH based on the ampere-hour integration method for qualified charging segments;

[0016] The open circuit voltage is estimated based on the current steady-state data and pseudo-static state data at the beginning of charging to calculate the actual SOC of each battery cell before and after charging, and the SOH of the battery cell is measured. The battery pack capacity health is scored by setting the SOH evaluation threshold of the single cell.

[0017] In one embodiment, screening out qualified charging segments specifically includes: by setting a time interval threshold, screening out mileage jump intervals during charging or charging time intervals greater than the set time interval threshold, dividing the screened mileage into charging cycles, and then screening out qualified charging segments according to the charging depth.

[0018] In one embodiment, the battery pack internal resistance health assessment specifically includes:

[0019] Preprocess the temperature and voltage data of the single cell to remove abnormal values ​​in temperature and voltage;

[0020] The internal resistance of each battery cell is calculated based on the voltage data and current data of the single battery cell in the two frames before and after charging, and the SOC and temperature data of the battery at the internal resistance are counted;

[0021] By setting the normal temperature threshold and the intermediate SOC threshold, all internal resistances at normal temperature and within the intermediate SOC range are screened, and the average value of the screened multiple cell internal resistances is taken as the average internal resistance of the battery pack;

[0022] The internal resistance SOH is calculated using the internal resistance value of the current vehicle state and the average internal resistance of the battery pack, and the score of the internal resistance SOH item is calculated according to the set internal resistance SOH score threshold.

[0023] In one embodiment, the battery pack capacity consistency evaluation specifically includes: calculating the difference between the maximum SOH and the minimum SOH of the single cell according to the SOH value of the single cell, and scoring the current vehicle battery pack capacity consistency by setting a battery pack capacity consistency evaluation threshold.

[0024] In one embodiment, the battery pack internal resistance consistency evaluation specifically includes:

[0025] Subtract the minimum value of all cell internal resistances from the maximum value of the single cell internal resistance, and divide the result by the average value of all cell internal resistances after excluding the maximum value and the minimum value of the single cell internal resistance. The internal resistance consistency of the vehicle battery pack is evaluated by setting the internal resistance consistency evaluation threshold.

[0026] In one embodiment, the battery pack thermal abuse assessment specifically includes:

[0027] Preprocess the temperature data of the single cell;

[0028] The frequency of frames exceeding the temperature threshold is calculated by setting the temperature threshold, and the thermal abuse of the battery pack is evaluated by setting the thermal abuse evaluation threshold.

[0029] In one embodiment, the battery pack temperature consistency assessment specifically includes:

[0030] Preprocess the temperature data of the single cell;

[0031] By setting the temperature difference threshold, the number of frames exceeding the temperature difference threshold is filtered out, the frequency of the frames exceeding the temperature difference threshold is calculated, and the temperature consistency of the battery pack is evaluated by the set temperature consistency evaluation threshold.

[0032] In one embodiment, the battery pack charge and discharge limit assessment specifically includes:

[0033] Compare the SOH of multiple cells in the battery;

[0034] The relative difference between the SOH of multiple single cells is obtained, and the charge and discharge limit of the battery pack is evaluated by setting the charge and discharge limit evaluation threshold.

[0035] In one embodiment, the battery status assessment method based on vehicle data also includes an insulation assessment of the entire vehicle system: obtaining the insulation data of the vehicle, determining whether there is a low insulation phenomenon when the vehicle is not charged, calculating the insulation frequency based on the number of frames in which the low insulation phenomenon occurs, and assessing the insulation of the entire vehicle system by setting an insulation assessment threshold.

[0036] The present invention has the following beneficial effects:

[0037] 1. Accuracy and reliability: The present invention comprehensively considers factors such as sampling time, current, SOC (remaining battery capacity), charging state, voltage of each single cell, temperature of each module, and insulation resistance, and adopts a combination of signal analysis and data drive to establish a detection method for multiple indicators inside the battery. This not only improves the characterization parameter system of the battery aging mechanism, but also optimizes the identification strategy of each battery difference.

[0038] 2. Safety: The present invention conducts a multi-scale comparative analysis of batteries through eight evaluation indicators, which helps car owners and maintenance personnel to accurately identify abnormal batteries and issue early warnings in a timely manner, thereby improving the safety of battery use.

[0039] 3. High efficiency: The calculation process of the present invention does not need to rely on additional offline equipment, and can remotely evaluate the safety of a large number of vehicle batteries without disturbing users. This feature greatly saves manpower, material resources and economic costs, and also provides a reliable basis for the recycling pricing and processing of used car lithium batteries. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 A schematic diagram of a flow chart of a battery status evaluation method based on vehicle data according to an embodiment of the present invention;

[0041] Figure 2 A schematic diagram of the application process of a battery status assessment method based on vehicle data in a vehicle containing RTM cycle data according to an embodiment of the present invention;

[0042] Figure 3 The figure is a schematic diagram of module decomposition of a battery status assessment method based on vehicle data according to an embodiment of the present invention. DETAILED DESCRIPTION

[0043] In order to make the purpose, technical scheme and advantages of the implementation of this application clearer, the technical scheme in the embodiment of this application will be described in more detail below in conjunction with the drawings in the embodiment of this application. In the drawings, the same or similar reference numerals represent the same or similar elements or elements with the same or similar functions. The described embodiments are part of the embodiments of this application, not all of them. The embodiments described below with reference to the drawings are exemplary and are intended to be used to explain this application, and should not be construed as limitations on this application. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application.

[0044] Figure 1 A battery status evaluation method based on vehicle data according to an embodiment of the present invention is a flowchart, wherein the battery status evaluation method based on vehicle data comprises:

[0045] Obtain vehicle data for a required time period, the vehicle data including battery temperature data, current data, voltage data, charging time data, and mileage data during charging;

[0046] Evaluating the battery status according to the vehicle data, including evaluating the battery capacity status, internal resistance status, temperature status, and charge and discharge status;

[0047] The evaluation of the battery capacity status includes capacity health evaluation and capacity consistency evaluation. The capacity health evaluation calculates the SOH of the entire battery pack and the SOH of a single cell according to the charging time data, the mileage data during charging, and the current data. The capacity consistency evaluation calculates the standard deviation of the capacities of multiple cells according to the SOH of a single cell to evaluate the capacity consistency of the current vehicle.

[0048] The evaluation of the internal resistance state of the battery includes an internal resistance health evaluation and an internal resistance consistency evaluation. The internal resistance health evaluation calculates the internal resistance and internal resistance SOH of a single cell according to the temperature data, current data and voltage data of the battery; the internal resistance consistency evaluation calculates the standard deviation of the internal resistance of multiple cells according to the internal resistance of the single cell to evaluate the consistency of the internal resistance of the cell;

[0049] The evaluation of the temperature state of the battery includes battery pack thermal abuse evaluation and temperature consistency evaluation. The battery pack thermal abuse evaluation sets a temperature threshold for the temperature data of the single cell, screens the number of frames exceeding the temperature threshold, and calculates the frequency of exceeding the temperature threshold to evaluate the battery pack thermal abuse record; the temperature consistency evaluation sets a temperature difference threshold for the temperature data of the single cell, calculates the frequency of exceeding the temperature difference threshold, and evaluates the battery pack temperature consistency;

[0050] The evaluation of the battery charge and discharge status includes battery pack charge and discharge limit evaluation. According to the SOH of a single battery cell, the SOH of multiple batteries is calculated to obtain a relative difference. By setting a charge and discharge limit evaluation threshold, the battery pack charge and discharge limit is evaluated.

[0051] Specifically, capacity health assessment: Calculate the SOH of the entire battery pack and the SOH of each cell based on the charging time data, mileage data during charging, and current data;

[0052] Internal resistance health assessment: Calculate the internal resistance and internal resistance SOH of a single cell based on the battery's temperature, current, and voltage data;

[0053] Capacity consistency assessment: Based on the SOH of a single cell, the standard deviation of the capacities of multiple cells is calculated to assess the capacity consistency of the current vehicle;

[0054] Internal resistance consistency assessment: Based on the internal resistance of a single cell, calculate the standard deviation of the internal resistance of multiple cells to assess the consistency of the internal resistance of the cells;

[0055] Battery pack thermal abuse assessment: Set a temperature threshold for the temperature data of a single cell, filter the number of frames that exceed the temperature threshold, and calculate the frequency of exceeding the temperature threshold to evaluate the battery pack thermal abuse record;

[0056] Temperature consistency assessment: Set a temperature difference threshold for the temperature data of a single cell and calculate the frequency of exceeding the temperature difference threshold to assess the temperature consistency of the battery pack;

[0057] Battery pack charge and discharge limit assessment: Based on the SOH of a single cell, the SOH of multiple cells is calculated to obtain the relative difference. By setting the charge and discharge limit assessment threshold, the charge and discharge limit of the battery pack is assessed.

[0058] Specifically, the vehicle data may be sorted by time, and when acquiring the vehicle data, the vehicle data of a certain time period may be selected.

[0059] Exemplarily, vehicle data from the past four months from now may be selected for battery pack internal resistance health assessment.

[0060] For example, Figure 2As shown, the vehicle data of some vehicle models are stored in the form of RTM cycle data, and the RTM cycle data includes data when the vehicle is charged and data when the vehicle is not charged. When the vehicle data is stored in the form of RTM cycle data, the vehicle battery can be evaluated by calling the RTM cycle data.

[0061] The proportion of the evaluation scores of these eight test items in the total vehicle score can be set. When the eight test items are completed, the total vehicle score is calculated by the set proportion of the evaluation scores of the eight test items in the total vehicle score, and the scores of each test item and the total vehicle score are output.

[0062] In one embodiment, the capacity health assessment specifically includes:

[0063] Based on the mileage data during charging, batch extract the data of all vehicles with the same mileage during charging;

[0064] Filter the mileage data during charging to select the charging segments that meet the requirements;

[0065] Calculate the battery pack SOH based on the ampere-hour integration method for qualified charging segments;

[0066] The open circuit voltage is estimated based on the current steady-state data at the beginning of charging and the pseudo-static state data to calculate the actual SOC of each battery cell before and after battery charging, and the SOH of the battery cell is measured. The battery pack capacity health is evaluated by setting the SOH evaluation threshold of the single cell.

[0067] In one embodiment, screening out qualified charging segments specifically includes: by setting a time interval threshold, screening out mileage jump intervals during charging or charging time intervals greater than the set time interval threshold, dividing the screened mileage into charging cycles, and then screening out qualified charging segments according to the charging depth.

[0068] Specifically, dividing the charging cycle is to divide and count the battery's charging and discharging process according to complete charging and discharging cycles to understand the number of cycles and life of the battery.

[0069] Furthermore, the vehicle data can be extracted based on the charging flag through the vehicle identification code (VIN code) and the start and end time of the query.

[0070] Exemplarily, the charging flag is determined as the charging status ('chargingstatus') of the RTM field being charging stopped ('CHARGING_STOPPED').

[0071] Exemplarily, in the charging segments that meet the conditions, the time interval threshold can be set to one hour, and the charging mileage with a charging time interval of more than 1 hour between the upper and lower frame times is screened out. The depth screening threshold can be set to 20%, and the charging segments that meet the conditions for calculating SOH are screened out as charging segments with a charging depth (dSOC) greater than 20%. The ampere-hour integration method measures the current and time dQ of the battery charging process, calculates the current actual capacity of the battery using dQ / dSOC, and estimates the SOH of the entire battery pack by calculating the ratio between the actual capacity of the battery and the rated capacity.

[0072] In one embodiment, the battery pack internal resistance health assessment specifically includes:

[0073] Preprocess the temperature and voltage data of the single cell to remove abnormal values ​​in temperature and voltage;

[0074] The internal resistance of each battery cell is calculated based on the voltage data and current data of the single battery cell in the two frames before and after charging, and the SOC and temperature data of the battery at the internal resistance are counted;

[0075] By setting the normal temperature threshold and the intermediate SOC threshold, all internal resistances at normal temperature and within the intermediate SOC range are screened, and the average value of the screened multiple cell internal resistances is taken as the average internal resistance of the battery pack;

[0076] The internal resistance SOH is calculated using the internal resistance value of the current vehicle state and the average internal resistance of the battery pack, and the score of the internal resistance SOH item is calculated according to the set internal resistance SOH evaluation threshold.

[0077] For example, vehicle data from the past four months is selected. The screening method is to remove the upper and lower 25th percentiles and take the average to obtain the internal resistance of each single cell at room temperature and in the middle SOC range.

[0078] For example, the abnormal temperature value is a temperature greater than 85°C or less than -40°C, and the abnormal voltage value is a single cell voltage greater than 4.3V or a single cell voltage less than 2.5V. The internal resistance in the temperature range of [20°C, 30°C] is screened according to the normal temperature threshold, and the internal resistance in the SOC range of [40%, 60%] is screened according to the intermediate SOC threshold.

[0079] In one embodiment, the battery pack capacity consistency evaluation specifically includes: calculating the difference between the maximum SOH and the minimum SOH of the single cell according to the SOH value of the single cell, and scoring the current vehicle battery pack capacity consistency by setting a battery pack capacity consistency evaluation threshold.

[0080] In one embodiment, the battery pack internal resistance consistency evaluation specifically includes:

[0081] Subtract the minimum value of all cell internal resistances from the maximum value of the single cell internal resistance, and divide the result by the average value of all cell internal resistances after excluding the maximum value and the minimum value of the single cell internal resistance. The internal resistance consistency of the vehicle battery pack is evaluated by setting the internal resistance consistency evaluation threshold.

[0082] In one embodiment, the battery pack thermal abuse assessment specifically includes:

[0083] Preprocess the temperature data of the single cell;

[0084] The frequency of frames exceeding the temperature threshold is calculated by setting the temperature threshold, and the thermal abuse of the battery pack is evaluated by setting the thermal abuse evaluation threshold.

[0085] Exemplarily, the temperature threshold may be set to 45° C., and the frequency is calculated as follows: the ratio of the number of vehicle frames with a temperature above 45° C. to the total number of vehicle data frames.

[0086] In one embodiment, the battery pack temperature consistency assessment specifically includes:

[0087] Preprocess the temperature data of the single cell;

[0088] By setting the temperature difference threshold, the number of frames exceeding the temperature difference threshold is filtered out, the frequency of the frames exceeding the temperature difference threshold is calculated, and the temperature consistency of the battery pack is evaluated by the set temperature consistency evaluation threshold.

[0089] In one embodiment, the battery pack charge and discharge limit assessment specifically includes:

[0090] Compare the SOH of multiple cells in the battery;

[0091] The relative difference between the SOH of multiple single cells is obtained, and the charge and discharge limit of the battery pack is evaluated by setting the charge and discharge limit evaluation threshold.

[0092] In one embodiment, the battery status assessment method based on vehicle data also includes an insulation assessment of the entire vehicle system: obtaining the insulation data of the vehicle, determining whether there is a low insulation phenomenon when the vehicle is not charged, calculating the insulation frequency based on the number of frames in which the low insulation phenomenon occurs, and assessing the insulation of the entire vehicle system by setting an insulation assessment threshold.

[0093] Exemplarily, the judgment standard of the low insulation phenomenon is: the vehicle insulation is lower than 510KΩ, and the uncharged state is judged as the charging state of the vehicle is non-charging.

[0094] For example, for some models of cars, an RTM field is provided, and the RTM field displays the charging status of the vehicle. When the charging status ('chargingstatus') displayed by the RTM field is non-charging ('NO_CHARGING'), the vehicle is in a non-charging state.

[0095] Specifically, one or more evaluation thresholds may be set for the SOH evaluation threshold of a single cell, the internal resistance SOH evaluation threshold, the battery pack capacity consistency evaluation threshold, the internal resistance consistency evaluation threshold, the thermal abuse evaluation threshold, the temperature consistency evaluation threshold, the charge and discharge limit evaluation threshold, and the insulation evaluation threshold according to different needs. These thresholds will be used to classify the calculated samples into different categories or intervals so as to evaluate and score the various performance characteristics of the battery.

[0096] The thresholds in the scoring criteria are formulated by experts in the battery field based on battery pack experimental data, actual vehicle operating data characteristics, etc.

[0097] This method mainly includes the following four dimensions and eight detection items, such as Figure 3 As shown, the vehicle battery is analyzed and scored from multiple dimensions:

[0098] SOH: This dimension includes two detection items: capacity health assessment and internal resistance health assessment. Among them, the battery capacity SOH characterizes the current battery's ability to store electrical energy relative to a new battery. It expresses the battery's state from the beginning to the end of its life in the form of a percentage. It is used to quantitatively describe the current battery's performance state and is a reflection of the battery's healthy lifespan. The internal resistance of the battery will affect the battery's discharge capacity and charging efficiency. When the internal resistance of the battery is abnormal, its own heat loss will increase, and it will not be able to discharge with a large current. In addition, if the internal resistance is large, the battery will heat up during use. Excessive temperature will cause the battery discharge operating voltage to decrease and the discharge time to shorten, which will have a serious impact on the battery's performance and life, and may even have the risk of spontaneous combustion.

[0099] Consistency: This dimension includes three test items: current capacity consistency evaluation, current internal resistance consistency evaluation, and battery pack charge and discharge limit evaluation. Among them, the current capacity consistency evaluation detects the capacity difference of each battery cell of the battery. If the capacity difference of each battery cell in the battery pack is large, it will cause the charge and discharge efficiency of some battery cells to be low, thus affecting the charge and discharge efficiency of the entire battery pack. The current internal resistance consistency evaluation detects the internal resistance difference of each battery cell. The inconsistent internal resistance of the battery cells makes the energy lost by each cell in the battery pack different during the discharge process, which will eventually affect the energy state of the battery cells. If the internal resistance difference in the battery pack is large, it will cause the battery pack to work unbalanced, and some battery cells may bear a greater load, thus affecting the life and performance of the entire battery pack. The battery pack charge and discharge limit evaluation examines whether there is a "high charge and low discharge" phenomenon when the battery pack is charged and discharged. In order to prevent overcharging and over-discharging of single cells, the vehicle can be equipped with a BMS system, and the BMS system will perform voltage protection on each string of cells according to the set protection voltage value. When the capacity of a single battery cell differs from that of other cells, the battery pack will be “charged high and discharged low”, resulting in a decrease in the available capacity of the entire battery pack.

[0100] Thermal management performance evaluation: This dimension includes two test items: battery pack thermal abuse record and temperature consistency evaluation. Battery pack thermal abuse record examines abnormal battery temperature. Battery performance is greatly affected by temperature. Excessive temperature will accelerate the rate of chemical reactions inside the battery. Batteries are prone to thermal runaway in high temperature environments, and may even cause fires or explosions. The temperature consistency evaluation within the battery pack examines the temperature differences within the battery. When the temperature difference is too large, the inconsistency of internal resistance, capacity, etc. will further increase, leading to accelerated differentiation of single cells, shortening the cycle life of the battery system, and even causing safety hazards.

[0101] Fault information: This dimension includes one test item: vehicle system insulation. If the high-voltage insulation system fails, the power of high-voltage components and electronic equipment may leak or short-circuit, causing potential dangers such as fire and electric shock, endangering the safety of vehicle owners and passengers. It is crucial to determine whether the insulation performance of the high-voltage system meets the relevant standards and requirements.

[0102] The present invention has the following beneficial effects:

[0103] 1. Accuracy and reliability: The present invention comprehensively considers factors such as sampling time, current, SOC (remaining battery capacity), charging state, voltage of each single cell, temperature of each module, and insulation resistance, and adopts a combination of signal analysis and data drive to establish a detection method for multiple indicators inside the battery. This not only improves the characterization parameter system of the battery aging mechanism, but also optimizes the identification strategy of each battery difference.

[0104] 2. Safety: The present invention conducts a multi-scale comparative analysis of batteries through eight evaluation indicators, which helps car owners and maintenance personnel to accurately identify abnormal batteries and issue early warnings in a timely manner, thereby improving the safety of battery use.

[0105] 3. High efficiency: The calculation process of the present invention does not need to rely on additional offline equipment, and can remotely evaluate the safety of a large number of vehicle batteries without disturbing users. This feature greatly saves manpower, material resources and economic costs, and also provides a reliable basis for the recycling pricing and processing of used car lithium batteries.

[0106] In the description of the present application, it should be noted that the terms used herein are only for describing specific embodiments, and are not intended to limit the exemplary embodiments according to the present application. For ease of description, the sizes of the various parts shown in the drawings are not drawn according to the actual proportional relationship. The technology, methods and equipment known to ordinary technicians in the relevant field may not be discussed in detail, but in appropriate cases, the technology, methods and equipment should be regarded as part of the authorization specification. In all examples shown and discussed here, any specific value should be interpreted as merely exemplary, rather than as a limitation. Therefore, other examples of the exemplary embodiments may have different values. It should be noted that similar numbers and letters represent similar items in the following drawings, so once an item is defined in one drawing, it does not need to be further discussed in subsequent drawings.

[0107] It should be noted that, in the present application, the terms "comprises", "includes" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also includes other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. It should also be pointed out that the scope of the methods and devices in the embodiments of the present application is not limited to performing functions in the order shown or discussed, and may also include performing functions in a substantially simultaneous manner or in reverse order according to the functions involved. For example, the described method may be performed in an order different from that described, and various steps may be added, omitted, or combined. In addition, the features described with reference to certain examples may be combined in other examples.

[0108] The above embodiments are provided for persons familiar with the art to implement or use the present application. Personnel familiar with the art can make various modifications or changes to the above embodiments without departing from the application concept of the present application. Therefore, the protection scope of the present application is not limited to the above embodiments, but should be the maximum scope of the innovative features mentioned in the claims.

Claims

1. A battery status evaluation method based on vehicle data, characterized in that: The battery status evaluation method based on vehicle data includes: Obtain vehicle data for a required time period, the vehicle data including battery temperature data, current data, voltage data, charging time data, and mileage data during charging; Evaluating the battery status according to the vehicle data, including evaluating the battery capacity status, internal resistance status, temperature status, and charge and discharge status; The evaluation of the battery capacity status includes capacity health evaluation and capacity consistency evaluation. The capacity health evaluation calculates the SOH of the entire battery pack and the SOH of a single cell according to the charging time data, the mileage data during charging, and the current data. The capacity consistency evaluation calculates the standard deviation of the capacities of multiple cells according to the SOH of a single cell to evaluate the capacity consistency of the current vehicle. The evaluation of the internal resistance state of the battery includes an internal resistance health evaluation and an internal resistance consistency evaluation. The internal resistance health evaluation calculates the internal resistance and internal resistance SOH of a single cell according to the temperature data, current data and voltage data of the battery; the internal resistance consistency evaluation calculates the standard deviation of the internal resistance of multiple cells according to the internal resistance of the single cell to evaluate the consistency of the internal resistance of the cell; The evaluation of the temperature state of the battery includes battery pack thermal abuse evaluation and temperature consistency evaluation. The battery pack thermal abuse evaluation sets a temperature threshold for the temperature data of the single cell, screens the number of frames exceeding the temperature threshold, and calculates the frequency of exceeding the temperature threshold to evaluate the battery pack thermal abuse record; the temperature consistency evaluation sets a temperature difference threshold for the temperature data of the single cell, calculates the frequency of exceeding the temperature difference threshold, and evaluates the battery pack temperature consistency; The evaluation of the battery charge and discharge status includes battery pack charge and discharge limit evaluation. According to the SOH of a single battery cell, the SOH of multiple batteries is calculated to obtain a relative difference. By setting a charge and discharge limit evaluation threshold, the battery pack charge and discharge limit is evaluated.

2. The battery status evaluation method based on vehicle data according to claim 1, characterized in that: Capacity health assessment specifically includes: Based on the mileage data during charging, batch extract the data of all vehicles with the same mileage during charging; Filter the mileage data during charging to select the charging segments that meet the requirements; Calculate the battery pack SOH based on the ampere-hour integration method for qualified charging segments; The open circuit voltage is estimated based on the current steady-state data and pseudo-static state data at the beginning of charging to calculate the actual SOC of each battery cell before and after charging, and the SOH of the battery cell is measured. The battery pack capacity health is scored by setting the SOH evaluation threshold of the single cell.

3. The battery status evaluation method based on vehicle data according to claim 2, characterized in that: Screening out qualified charging segments specifically includes: setting a time interval threshold, screening out mileage jump intervals during charging or charging time intervals greater than the set time interval threshold, dividing the screened mileage into charging cycles, and then screening out qualified charging segments based on charging depth.

4. The battery status evaluation method based on vehicle data according to claim 1, characterized in that: The battery pack internal resistance health assessment specifically includes: Preprocess the temperature and voltage data of the single cell to remove abnormal values ​​in temperature and voltage; The internal resistance of each battery cell is calculated based on the voltage data and current data of the single battery cell in the two frames before and after charging, and the SOC and temperature data of the battery at the internal resistance are counted; By setting the normal temperature threshold and the intermediate SOC threshold, all internal resistances at normal temperature and within the intermediate SOC range are screened, and the average value of the screened multiple cell internal resistances is taken as the average internal resistance of the battery pack; The internal resistance SOH is calculated using the internal resistance value of the current vehicle state and the average internal resistance of the battery pack, and the score of the internal resistance SOH item is calculated according to the set internal resistance SOH score threshold.

5. The battery status evaluation method based on vehicle data according to claim 2, characterized in that: The battery pack capacity consistency assessment specifically includes: calculating the difference between the maximum SOH and the minimum SOH of the single cell according to the SOH value of the single cell, and scoring the current vehicle battery pack capacity consistency by setting the battery pack capacity consistency assessment threshold.

6. The battery status evaluation method based on vehicle data according to claim 1, characterized in that: The battery pack internal resistance consistency assessment specifically includes: Subtract the minimum value of all cell internal resistances from the maximum value of the single cell internal resistance, and divide the result by the average value of all cell internal resistances after excluding the maximum value and the minimum value of the single cell internal resistance. The internal resistance consistency of the vehicle battery pack is evaluated by setting the internal resistance consistency evaluation threshold.

7. The battery status evaluation method based on vehicle data according to claim 1, characterized in that: Battery pack thermal abuse assessment specifically includes: Preprocess the temperature data of the single cell; The frequency of frames exceeding the temperature threshold is calculated by setting the temperature threshold, and the thermal abuse of the battery pack is evaluated by setting the thermal abuse evaluation threshold.

8. The battery status evaluation method based on vehicle data according to claim 1, characterized in that: Battery pack temperature consistency assessment specifically includes: Preprocess the temperature data of the single cell; By setting the temperature difference threshold, the number of frames exceeding the temperature difference threshold is filtered out, the frequency of the frames exceeding the temperature difference threshold is calculated, and the temperature consistency of the battery pack is evaluated by the set temperature consistency evaluation threshold.

9. The battery status evaluation method based on vehicle data according to claim 2, characterized in that: The battery pack charge and discharge limit assessment specifically includes: Compare the SOH of multiple cells in the battery; The relative difference between the SOH of multiple single cells is obtained, and the charge and discharge limit of the battery pack is evaluated by setting the charge and discharge limit evaluation threshold.

10. The battery status evaluation method based on vehicle data according to claim 1, characterized in that: The battery status assessment method based on vehicle data also includes the insulation assessment of the entire vehicle system: obtaining the insulation data of the vehicle, determining whether there is low insulation when the vehicle is not charged, calculating the insulation frequency based on the number of frames in which the insulation phenomenon occurs, and assessing the insulation of the entire vehicle system by setting an insulation assessment threshold.

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