Method for testing endurance of pure electric vehicle in low-temperature environment

Abstract

The invention discloses a battery electric vehicle endurance test method in a low-temperature environment. The method comprises the following steps: step 1, charging a vehicle corresponding to a to-be-tested vehicle type; 2, driving the to-be-tested vehicle at a low temperature according to the comprehensive road condition until the electric quantity is exhausted, and recording and obtaining the electric quantity SOC change, the meter display endurance mileage change data and the actual mileage statistical data in the testing process; step 3, slowly charging the vehicle which runs out of the electric quantity in the step 2 until the vehicle is fully charged, and counting the charging electric quantity; and step 4, acquiring endurance parameters based on the data acquired in the step 2 and the step 3. The method has the advantages that the endurance parameters at the low temperature can be accurately, reliably and scientifically quantitatively tested, and a basic reference index is provided for driving of a vehicle at the low temperature.

Description

Technical Field

[0001] The present invention relates to the field of pure electric vehicles, and in particular to a method for testing the endurance of pure electric vehicles in a low-temperature environment. Background Art

[0002] In the user market, due to the characteristics of charging resources, charging time and battery materials, the first demand of market users for pure electric vehicles is still the cruising range, and battery characteristics and vehicle energy consumption are the main factors affecting the cruising range of pure electric vehicles, especially in northern regions in winter, which is still a forbidden zone for pure electric vehicles. The inaccurate cruising range and reduced cruising range of pure electric vehicle products of all automobile OEMs are still the biggest complaints of market users.

[0003] Car companies with existing technology generally use NEDC, WLTC and other standard working conditions to conduct endurance tests in laboratories or on benches for the vehicles they develop. The test temperature is generally the optimal temperature of the battery. The endurance mileage tested is quite different from the endurance mileage of real drivers. Users generally use the reduced endurance to evaluate the endurance of electric vehicles. Especially in winter environments, since the battery performance is affected in winter environments, its endurance mileage is quite different from the endurance mileage of NEDC, WLTC, etc., and it is impossible to provide a more accurate endurance reference for the user's model. This does not meet the user's endurance mileage estimate for the model vehicle in winter environments, affecting the user's endurance expectations for the vehicle. Therefore, it is necessary to conduct scientific and reliable tests on the endurance parameters of the vehicle at low temperatures to meet the user's demand for the endurance mileage of the vehicle at low temperatures. Summary of the invention

[0004] The purpose of the present invention is to overcome the shortcomings of the prior art and provide a pure electric vehicle endurance test method in a low temperature environment, which is used to scientifically and accurately test the endurance parameters of the electric vehicle at low temperatures to meet the user's needs for endurance estimation at low temperatures.

[0005] In order to achieve the above object, the technical solution adopted by the present invention is: a method for testing the endurance of a pure electric vehicle in a low temperature environment, comprising the following steps:

[0006] Step 1: Charge the vehicle corresponding to the model to be tested;

[0007] Step 2: Drive the vehicle to be tested under low temperature and comprehensive road conditions until the battery is exhausted. During the test, record the SOC change, displayed range change data, and actual mileage statistics;

[0008] Step 3: Slowly charge the vehicle that has run out of power in step 2 until it is fully charged, and count the charged power;

[0009] Step 4: Obtain the battery life parameters based on the data collected in steps 2 and 3.

[0010] Step one includes: after powering on the vehicle to the Ready state in a low temperature environment of -10°C or below, turning off all accessories and intelligent function switches through the central control screen or switch buttons, and then using a slow charging pile that meets national standards to charge the test vehicle.

[0011] Step 1 also includes slow charging. When the vehicle displays that the battery is fully charged and the gun automatically jumps, or the battery level displays 100% and there is no change within the set time range, the charging is judged to be completed. After charging is completed, the vehicle will exit the high-voltage power in the Ready state and disconnect the vehicle's low-voltage battery.

[0012] After charging is completed, place the vehicle in a low-temperature open-air environment and let it stand for a set time. If no abnormalities occur during the charging process or the standing process, proceed to step 2, otherwise the test is terminated.

[0013] Step 2 includes connecting the vehicle's low-voltage battery after step 1 is completed. After the high voltage of the entire vehicle reaches the Ready state, except for the driving safety functions that are forced to be turned on by default, other auxiliary and intelligent functions remain turned off, and then the road test process begins.

[0014] After entering the road test process, select the vehicle driving mode, set the energy recovery mode, set the air conditioning working mode, and then drive the vehicle according to the selected comprehensive road conditions under the simulated user environment. The test ends when the displayed battery power SOC or the remaining cruising range is 0.

[0015] During the vehicle driving process in step two, the battery power and cruising range mileage data are collected and recorded in real time, including the remaining range display drop value and the corresponding actual driving mileage in each 10% battery power SOC interval, as well as the actual driving mileage from the beginning to the end of the test; if no abnormal situation occurs during the entire cruising range discharge test process in step two, the test passes and enters step three.

[0016] After the test in step 2 is completed, place the vehicle in a warm room and let it sit for a set time. Then use a slow charging pile that meets national standards to charge the test vehicle until the vehicle shows that the battery is fully charged and the gun automatically jumps, or the battery level shows 100% and there is no change within the set time. If no abnormal situation occurs during the charging process, end step 3 and record the charging power data in the warm room environment.

[0017] In step 1 and step 3, the abnormal charging test status includes the following: the charging gun electronic lock is locked during the charging process, the unlocking fails to respond normally, or / and the charging pile fails to interact with the vehicle to start charging, or / and the charging gun jumps abnormally to terminate charging, or / and the battery or charger related fault lights are lit;

[0018] Abnormal discharge test status includes the vehicle being unable to power on and ready to start after being left stationary and cold soaked during driving, or / and the vehicle power being cut off during driving, or / and the battery power SOC being suddenly drastically corrected during driving, or / and the fault lights on the vehicle instruments being lit during driving.

[0019] The data recorded during the test in step 2 is comprehensively analyzed by using multiple vehicle tests, and the collected data with large errors are eliminated and the standard deviation is used to process the deviation to obtain the final statistical endurance data.

[0020] The advantages of the present invention are: (1) it can accurately, reliably and scientifically perform quantitative tests on the endurance parameters at low temperatures, providing a basic reference index for vehicles driving at low temperatures; (2) after testing the endurance reliability test of pure electric vehicles in a low-temperature environment, it can provide each OEM's pure electric vehicle products with accurate endurance and energy consumption real level and process data in a low-temperature environment, providing ideas and directions for the optimization and adjustment of subsequent products. (3) after testing the endurance reliability test of pure electric vehicles in a low-temperature environment, it can provide market users with real endurance data of automobile products, providing users with objective data comparison of pure electric vehicle products to purchase automobile products that meet their expectations. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The following is a brief description of the contents expressed in the drawings of the present specification and the marks in the drawings:

[0022] Figure 1 : A flowchart of a test for testing the endurance reliability of a pure electric vehicle in a low temperature environment in an embodiment of the present invention;

[0023] Figure 2 : The final data processing flow chart of the present invention collected by the equipment device. DETAILED DESCRIPTION

[0024] The specific implementation of the present invention will be further explained in detail below by describing the optimal embodiment with reference to the accompanying drawings.

[0025] This solution is mainly used for testing the winter cruising range parameters of the models to be tested or developed. The cruising range parameters are obtained by the test method in this embodiment. In the process of vehicle generation and development, basic cruising range parameters can be provided for research and development, and a basis for subsequent research and development adjustments can be provided; at the same time, it can also provide consumers with an estimated reference for the winter cruising range of the vehicle after the vehicle is sold, optimize the user experience, and avoid the defects of the prior art that the winter cruising range is greatly reduced compared to the cruising range under NEDC, WLTC and other working conditions, and the user cannot estimate the cruising range. The specific cruising range test scheme is as follows:

[0026] like Figure 1 , 2 As shown, a method for testing the endurance of a pure electric vehicle in a low temperature environment comprises the following steps:

[0027] Step 1: Charge the vehicle corresponding to the model to be tested; at this time, in a low temperature environment, charge the vehicle of the model to be tested to a full power state so that it meets the basic requirements of the endurance test;

[0028] Step 2: The fully charged test vehicle is driven under low temperature according to comprehensive road conditions until the battery is exhausted. During the test, the changes in the SOC of the battery, the change data of the displayed cruising range, and the actual mileage statistics are recorded. The comprehensive road conditions generally select the urban road conditions commonly used by users and some high-priced highway conditions to simulate the user's real usage scenarios. The vehicle is driven and controlled through real usage scenarios to obtain parameters such as the SOC of the battery and the cruising range during driving.

[0029] Step 3: Slowly charge the vehicle that has run out of power in step 2 until it is fully charged, and count the charged power; this step is to obtain the vehicle's power consumption. For the vehicle that has run out of power after the test in step 2, charge it under a standard environment to test its charging power data and obtain how much power it has charged.

[0030] Step 4: Based on the data collected in steps 2 and 3, the endurance parameters are obtained. The endurance parameters include the endurance mileage, the charging power, and the endurance mileage corresponding to every 10% power consumption. These parameters obtained in steps 2 and 3 can provide basic winter endurance parameters for the subsequent development of the vehicle. The endurance mileage, power consumption, etc. can also be used as reference data on the user side to provide a reference basis for users' winter vehicle use.

[0031] Figure 1 to Figure 2 The specific implementation of the test for testing the endurance reliability of a pure electric vehicle in a low temperature environment of the present invention is shown. Figure 1 is a flowchart of a test method and device for testing the endurance reliability of a pure electric vehicle in a low temperature environment of the present invention in this embodiment, Figure 2It is a flowchart of the final data processing collected by the equipment provided in this embodiment.

[0032] like Figure 1 As shown, in this embodiment, a method for testing the endurance reliability of pure electric vehicles by simulating user driving in a low temperature environment is as follows: Step 1: prepare a test product of a main-selling pure electric vehicle that meets the requirements of public sale in the market or select a test vehicle as a low-temperature test product in the vehicle development stage; after the vehicle is powered on to the Ready state in a low temperature environment of -10°C or below, turn off all accessories or intelligent function switches through the central control screen or the switch button, and then use a slow charging pile that meets national standards to charge the test vehicle until the vehicle displays that the battery is fully charged and the gun automatically jumps or the battery power displays 100% and there is no change within 30 minutes, and the test vehicle is cut off; after charging is completed, the vehicle exits the high voltage in the Ready state and disconnects the low-voltage battery of the vehicle, and the vehicle is left stationary in an open air environment for 24h to 36h. No abnormal situation occurs during the entire charging and stationary process, such as the vehicle cannot be high-voltage, the charging gun cannot be locked and unlocked, and cannot be charged, so as to determine whether the vehicle can meet the subsequent test requirements; if the vehicle state is abnormal, the test is terminated and the abnormal reasons are specifically analyzed and counted; if the vehicle state is normal, proceed to the next step;

[0033] Step 2: After the resting is completed, connect the low-voltage battery. After the high voltage of the vehicle reaches the Ready state, except for the driving safety functions that are forced to be turned on by default, other auxiliary and intelligent functions remain turned off. After starting the test, use the vehicle's standard driving mode (economic mode or energy-saving mode), set the standard or driving mode default energy recovery mode, set the air conditioning to 24°C, and blow the foot defrost mode (if the temperature is too high during the test, open the window for ventilation for a while), select the city or suburbs or highway or a comprehensive working condition fixed route covering the city, suburbs, and highways to simulate the user's habitual vehicle operation method and drive the vehicle, and set the instrument to display the battery power SOC or the remaining driving range. The test is terminated when the battery is discharged to 0 or no value is displayed. During the test, the recording device is used to record and count the remaining battery life display drop and actual mileage statistics in each 10% battery power SOC interval. The test vehicle must be driven in a safe state in compliance with traffic regulations throughout the entire process. During the driving and discharging process, check whether the vehicle status is abnormal, such as the vehicle cannot be high-voltage, the air conditioning and heating function fails, the instrument battery life or power SOC display jumps, the fault warning light is on during driving, etc., to determine whether the vehicle can meet the subsequent test requirements; if the vehicle status is abnormal, the test is terminated and the abnormal cause is specifically analyzed and counted; if the vehicle status is normal, proceed to the next step;

[0034] Step 3: After the discharge test is completed, park the vehicle in a warm room with an indoor temperature of 20℃ to 30℃ and let it stand for more than 12 hours. Then use a slow charging pile that meets national standards to charge the test vehicle. Charge until the vehicle shows that the battery is fully charged and the gun automatically jumps or the battery power shows 100% and there is no change within 30 minutes. During the entire charging process, monitor whether there are any abnormal conditions in the power battery status, such as the instrument endurance or power SOC display jump, the battery BMS and the charger cannot complete the charging alarm, the power battery voltage jumps during the charging process and the charging is terminated. If not, the car is qualified and the test is terminated; otherwise, the test is terminated and specific analysis and statistics of abnormal reasons are carried out.

[0035] Specifically, the abnormal vehicle status in the above steps one, two, and three refers to the inability to light up the power battery status fault light on the high-voltage instrument of the vehicle, or / and the air conditioning, lights, exterior mirror adjustment and other related electrical functions cannot operate normally, or / and the instrument displays a large jump in the cruising range or the state of charge SOC (State of Charge), or / and the charging gun electronic lock cannot be locked or unlocked, or / and the performance power of the entire vehicle is limited, resulting in driving safety, or / and the entire vehicle makes abnormal noises or shakes during driving, affecting the user's sense of driving safety, or / and the instrument vehicle fault warning light is on.

[0036] Specifically, in the above steps one and three, when charging, use a charging pile that complies with national unified standards and functions normally to charge the vehicle, insert the charging gun on the charging pile into the vehicle's charging port to charge, and stop charging and pull out the charging gun when the charging pile panel displays that the vehicle is fully charged.

[0037] In the present invention, multiple vehicles of the same configuration or multiple vehicles of different models are tested simultaneously, and each test vehicle is tested with at least 3 groups of valid data or more. The more the test data sample volume, the more accurate the test result analysis of the model. Figure 2As shown, the data obtained include the endurance of each SOC drop stage. Since every 10% is an interval, the drop stage can be divided into 90%-100%, 80%-90%, 70%-60% and other intervals. The endurance of each drop interval needs to be recorded. This data has important reference value for the research and development of automobile companies, so the data is recorded and counted. When performing statistics and records, the endurance statistics of each stage of the SOC of a single vehicle, the endurance statistics of multiple groups of SOC of a single vehicle, and the endurance statistics of each stage of the SOC of multiple vehicles of the same model are performed respectively; based on the statistical data, the endurance parameters are obtained by taking every 10% as a stage, and then the data of each group are compared and reviewed. When the data of a certain stage deviates greatly from the data of other stages, it is necessary to process and exclude the data or perform deviation processing. For example, the final result data is compared with the actual road mileage and the mileage displayed on the instrument, the SOC endurance mileage of each stage of a single vehicle or the SOC endurance of multiple groups of single vehicles at each stage, or the SOC endurance of multiple vehicles of the same model at each stage. When the deviation of the results of multiple groups of data is large, the standard deviation is used for deviation processing to obtain the final data result.

[0038] In the present invention, a slow charging pile is used to charge the test vehicle before and after the test in order to reduce objective test errors. The battery cell materials, layout forms and control strategies of pure electric test models of different OEMs are different. For example, some OEMs use DC fast charging piles for charging due to battery safety considerations. The charging current is relatively large. When the voltage of a certain module or a certain single cell of the battery reaches the rated upper limit condition, the charging will be requested to end. It is assumed that the full charge state has been reached, and the SOC value displayed on the instrument will be automatically corrected to 100%. Therefore, a slow charging pile with a smaller charging current is used to reduce some objective errors.

[0039] In the present invention, after charging is completed, the initial test state of the vehicle will be inconsistent due to differences in vehicle design strategies by various OEMs. Therefore, it is necessary to let the vehicle stand still to simulate the user's vehicle usage under the most extreme environment. During the standing still process, the high voltage is reduced and the low-voltage battery of the entire vehicle is disconnected to ensure that the test vehicle will not be affected by its own auxiliary functions, such as self-heating of the battery pack to maintain battery discharge performance, self-cleaning of the passenger compartment, anti-theft radar and external camera, etc., which will affect the battery power consumption in the background work and further affect the accuracy of the subsequent endurance test results.

[0040] In the present invention, in order to eliminate the impact of related auxiliary functions configured by different OEMs for user usage scenarios on vehicle endurance during actual road tests, all other auxiliary functions are turned off as much as possible except for the mandatory default-on functions related to safe driving. Therefore, only functions related to safe driving are retained, and other functions are turned off.

[0041] In the present invention, when selecting the test working condition, a single working condition can be used to test the endurance under different working conditions, or a comprehensive working condition test can be used. However, after the working condition is selected, all tests must be carried out under the same working condition to maintain the uniformity of the measurement data. Due to the difference in tire models of each test vehicle, the driving range displayed by the instrument may cause errors based on the calculation of the wheel speed sensor. When analyzing the test results, deviation processing must be performed based on the actual road length. Select a fixed route in the city or suburbs or highway or a comprehensive working condition covering the city, suburbs, and highway to simulate the user's habitual vehicle operation mode of driving the vehicle. No matter whether it is a single urban working condition, suburban working condition, highway working condition or comprehensive working condition, once selected, other tests are tested according to the same working condition, that is, the same route.

[0042] In the present invention, the vehicle is parked in a heating room after the test because the battery materials, layout forms and control strategies used by various OEMs are different. The vehicle status at this time will produce slight differences in charging, and 20℃ to 30℃ is the optimal temperature range for the chemical activity of general battery materials. Charging after a period of rest can reduce the statistical error of energy consumption.

[0043] In the present invention, the rest time is calculated from the time when the low-voltage battery is disconnected after charging is completed, and it can be more than 24 hours. At this time, the temperature of all parts of the whole vehicle changes with the ambient temperature. The road test time is mainly during the day, and the night test time does not exceed 5% of the total mileage.

[0044] In the present invention, through the SOC endurance statistics at different stages and the multi-sample data statistics, when performing data analysis and statistics of the test results, according to the SOC endurance statistics comparison of the bicycle at different stages and the endurance comparison of the same SOC stage under different groups of samples, when the data comparison has a large error, the standard deviation is used for deviation processing to obtain the final accurate data, such as Figure 2 shown.

[0045] Specifically, the entire test process uses data acquisition equipment to collect and monitor the vehicle's charging, driving, and fault status data for statistics and analysis. Data related to the cruising range can be collected before and during the test. These data are used as the cruising range parameters of the tested vehicle model and can provide basic parameters for subsequent development.

[0046] The present invention, after testing the endurance reliability of pure electric vehicles in a low-temperature environment, can provide the pure electric vehicle products of each host manufacturer with accurate endurance and real level and process data of energy consumption in a low-temperature environment, and provide ideas and directions for the optimization and adjustment of subsequent products. At the same time, it can also provide market users with real automobile product endurance data, and provide users with objective data comparison of pure electric vehicle products to purchase automobile products that meet their expectations.

[0047] 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 protection scope of the present invention.

Claims

1. A method for testing the endurance of a pure electric vehicle in a low temperature environment, characterized in that: The steps include: Step 1: Charge the vehicle corresponding to the model to be tested; Step 2: Drive the vehicle to be tested under low temperature and comprehensive road conditions until the battery is exhausted. During the test, record the SOC change, displayed range change data, and actual mileage statistics; Step 3: Slowly charge the vehicle that has run out of power in step 2 until it is fully charged, and count the charged power; Step 4: Obtain the battery life parameters based on the data collected in steps 2 and 3.

2. A method for testing the endurance of a pure electric vehicle in a low temperature environment as claimed in claim 1, characterized in that: Step one includes: after powering on the vehicle to the Ready state in a low temperature environment of -10°C or below, turning off all accessories and intelligent function switches through the central control screen or switch buttons, and then using a slow charging pile that meets national standards to charge the test vehicle.

3. A method for testing the endurance of a pure electric vehicle in a low temperature environment as claimed in claim 2, characterized in that: Step 1 also includes slow charging. When the vehicle displays that the battery is fully charged and the gun automatically jumps, or the battery level displays 100% and there is no change within the set time range, the charging is judged to be completed. After charging is completed, the vehicle will exit the high-voltage power in the Ready state and disconnect the vehicle's low-voltage battery.

4. A method for testing the endurance of a pure electric vehicle in a low temperature environment as claimed in claim 3, characterized in that: After charging is completed, place the vehicle in a low-temperature open-air environment and let it stand for a set time. If no abnormalities occur during the charging process or the standing process, proceed to step 2, otherwise the test is terminated.

5. A method for testing the endurance of a pure electric vehicle in a low temperature environment as claimed in claim 1, characterized in that: Step 2 includes connecting the vehicle's low-voltage battery after step 1 is completed. After the high voltage of the entire vehicle reaches the Ready state, except for the driving safety functions that are forced to be turned on by default, other auxiliary and intelligent functions remain turned off, and then the road test process begins.

6. A method for testing the endurance of a pure electric vehicle in a low temperature environment as claimed in claim 5, characterized in that: After entering the road test process, select the vehicle driving mode, set the energy recovery mode, set the air conditioning working mode, and then drive the vehicle according to the selected comprehensive road conditions under the simulated user environment. The test ends when the displayed battery power SOC or the remaining cruising range is 0.

7. A method for testing the endurance of a pure electric vehicle in a low temperature environment as claimed in claim 6, characterized in that: During the vehicle driving process in step two, the battery power and cruising range mileage data are collected and recorded in real time, including the remaining range display drop value and the corresponding actual driving mileage in each 10% battery power SOC interval, as well as the actual driving mileage from the beginning to the end of the test; if no abnormal situation occurs during the entire cruising range discharge test process in step two, the test passes and enters step three.

8. A method for testing the endurance of a pure electric vehicle in a low temperature environment as claimed in claim 1, characterized in that: After the test in step 2 is completed, place the vehicle in a warm room and let it sit for a set time. Then use a slow charging pile that meets national standards to charge the test vehicle until the vehicle shows that the battery is fully charged and the gun automatically jumps, or the battery level shows 100% and there is no change within the set time. If no abnormal situation occurs during the charging process, end step 3 and record the charging power data in the warm room environment.

9. A method for testing the endurance of a pure electric vehicle in a low temperature environment as claimed in claim 1, characterized in that: In step 1 and step 3, the abnormal charging test status includes the following: the charging gun electronic lock is locked during the charging process, the unlocking fails to respond normally, or / and the charging pile fails to interact with the vehicle to start charging, or / and the charging gun jumps abnormally to terminate charging, or / and the battery or charger related fault lights are lit; Abnormal discharge test status includes the vehicle being unable to power on and ready to start after being left stationary and cold soaked during driving, or / and the vehicle power being cut off during driving, or / and the battery power SOC being suddenly drastically corrected during driving, or / and the fault lights on the vehicle instruments being lit during driving.

10. A method for testing the endurance of a pure electric vehicle in a low temperature environment as claimed in claim 1, characterized in that: The data recorded during the test in step 2 is comprehensively analyzed by using multiple vehicle tests, and the collected data with large errors are eliminated and the standard deviation is used to process the deviation to obtain the final statistical endurance data.

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