Methods, devices, and computer-readable storage media for evaluating the residual performance of electric vehicles.

Abstract

Invention details;

Description

Electric vehicle residual performance evaluation method, device and computer-readable storage medium

[0001] Related applications

[0002] This application claims priority to Chinese patent application No. 202111344633.0 filed on November 12, 2021, the entire contents of which are incorporated herein by reference. Technical Field

[0003] The present application relates to the field of electric vehicles, and in particular to a method, device, and computer-readable storage medium for evaluating the residual performance of electric vehicles. Background Art

[0004] At present, the domestic electric vehicle ownership exceeds 1% and is growing year by year. Electric vehicles use electric motors as driving devices and are powered by on-board rechargeable batteries or other energy storage devices. They have the advantages of zero emissions, high efficiency, quietness, smooth operation, easy driving, low maintenance costs, and a wide range of electricity sources. Therefore, they are regarded as a long-term development goal among existing new energy vehicle technologies.

[0005] With the increasing popularity of electric vehicles, the safety and durability of their onboard power batteries are attracting increasing attention. In terms of safety, most electric vehicle accidents originate from the explosion of aging power batteries. Therefore, how to quickly and accurately assess the health of electric vehicle power batteries is extremely important.

[0006] However, there is currently a lack of authoritative, low-cost, and rapid evaluation methods for the residual performance of electric vehicles in the industry.

[0007] Application Contents

[0008] The main purpose of this application is to provide a method, device and computer-readable storage medium for evaluating the remaining performance of electric vehicles, aiming to solve the technical problem of how to improve the evaluation reliability and efficiency of the remaining performance of electric vehicles while saving evaluation costs.

[0009] To achieve the above objectives, the present application provides a method for evaluating the remaining performance of an electric vehicle, the method comprising the following steps:

[0010] Performing discharge tests and charge tests on power batteries of electric vehicles at different preset loss states to obtain charging condition energy and charging condition DC resistance of the power batteries;

[0011] Calculating according to the charging condition energy and the charging condition DC resistance to obtain the charging condition energy attenuation rate and the charging condition DC resistance expansion of the electric vehicle;

[0012] The health of the electric vehicle and the remaining mileage in its life cycle are calculated based on the energy attenuation rate and DC resistance expansion degree of the charging condition and the mileage that the electric vehicle has traveled.

[0013] In one embodiment, the step of performing a discharge test and a charge test on a power battery of an electric vehicle in different preset loss states to obtain the charging condition energy and the charging condition DC resistance of the power battery includes:

[0014] Perform discharge test and charge test on the power battery in low loss state to obtain the initial charging condition energy W of the power battery. b And the DC resistance R of the initial charging condition b ;

[0015] Perform discharge test and charge test on the power battery in high loss state to obtain the terminal charging condition energy W of the power battery. e and the DC resistance R of the terminal charging condition e ;

[0016] Perform discharge test and charge test on the power battery in the medium loss state to obtain the driving stage charging condition energy W of the power battery. r And the DC resistance R of the charging condition during the driving stage r .

[0017] In one embodiment, the step of calculating based on the charging condition energy and the charging condition DC resistance to obtain the charging condition energy attenuation rate and the charging condition DC resistance expansion of the electric vehicle includes:

[0018] W b 、W e and W r Substitute into the energy decay rate formula of charging condition to calculate the energy decay rate of charging condition

[0019] R b 、R e and R r Substitute it into the DC resistance expansion formula under charging condition to calculate the DC resistance expansion under charging condition.

[0020] In one embodiment, the step of calculating the health and remaining mileage of the electric vehicle based on the energy decay rate and DC resistance expansion of the charging condition and the mileage of the electric vehicle includes:

[0021] Get the mileage L of the electric vehicle, and and Substitute into the health formula of the electric vehicle for calculation to obtain the health of the electric vehicle

[0022] L, and Substitute into the remaining driving range formula of the electric vehicle's life cycle to calculate the remaining driving range L of the electric vehicle's life cycle. r .

[0023] In one embodiment, the step of performing a discharge test on the power battery in a low-loss state includes:

[0024] The electric vehicle in which the power battery in the low-loss state is located is controlled to travel at a preset speed v to discharge the power battery until the voltage of the power battery reaches a preset cut-off discharge voltage U low ;

[0025] The electric vehicle in which the power battery in the low-loss state is located is controlled to remain stationary for a first preset time τ1 until the voltage of the power battery is in a preset stable state.

[0026] In one embodiment, the step of performing a charging test on the power battery in a low-loss state includes:

[0027] The power battery is charged with a first preset current I1 until the voltage of the power battery reaches a preset cut-off charging voltage U up ;

[0028] Record the real-time charging voltage U, the starting charging time t1 and the ending charging time t2 during the charging process;

[0029] Stop charging and control the electric vehicle where the power battery in the low-loss state is located to stand for a second preset time τ2 until the voltage of the power battery drops back to the preset stable state;

[0030] The initial charging condition energy W of the power battery is obtained b The steps include:

[0031] Substitute U, t1 and t2 into the charging condition energy formula to calculate the initial charging condition energy W b .

[0032] In one embodiment, the initial charging condition energy W of the power battery is obtained. b The steps that follow include:

[0033] Execution steps: Perform a discharge test on the power battery in a low-loss state;

[0034] The step of performing a charging test on the power battery in a low-loss state further includes:

[0035] The power battery is charged with a second preset current I2 until the voltage of the power battery reaches a preset mid-value voltage U mid , where U mid =(U low +U up ) / 2;

[0036] Stop charging and control the electric vehicle where the power battery in the low-loss state is located to stand for a second preset time τ2 until the voltage of the power battery drops back to the preset stable state;

[0037] The power battery is charged with a third preset current I3 until the voltage of the power battery reaches U mid ;

[0038] Stop charging and control the electric vehicle where the power battery in the low-loss state is located to stand for a third preset time τ3 until the voltage of the power battery drops back to the preset stable state;

[0039] Calculate the stable power battery voltage and U mid The absolute value of the difference.

[0040] In one embodiment, the calculated stabilized power battery voltage and U mid The absolute value of the difference step is followed by:

[0041] Determine whether the absolute value of the difference is less than the preset stable voltage value U of the power battery s ;

[0042] Determine that the absolute value of the difference is less than the preset stable voltage value U of the power battery s , record the voltage U of the power battery mid1 ;

[0043] The power battery is continuously charged at I2, and the voltage U of the power battery after the fourth preset time τ4 is recorded. mid2 ;

[0044] The DC resistance R of the power battery at the initial charging condition is obtained. b The steps include:

[0045] Will U mid1 、U mid2 Substitute I2 into the charging condition DC resistance formula to calculate the initial charging condition DC resistance R b .

[0046] In one embodiment, the power battery in a high loss state is subjected to a discharge test and a charge test to obtain the terminal charging condition energy W of the power battery. e and the DC resistance R of the terminal charging condition e The steps include:

[0047] The electric vehicle in which the power battery in a high loss state is located is controlled to travel at a preset speed v to discharge the power battery until the voltage of the power battery reaches a preset cut-off discharge voltage U low ;

[0048] Controlling the electric vehicle in which the power battery in the high-loss state is located to stand for a first preset time τ1 until the voltage of the power battery is in a preset stable state;

[0049] The power battery is charged with a first preset current I1 until the voltage of the power battery reaches a preset cut-off charging voltage U up ;

[0050] Record the real-time charging voltage U, the starting charging time t1 and the ending charging time t2 during the charging process;

[0051] Stop charging and control the electric vehicle where the power battery in the high-loss state is located to stand for a second preset time τ2 until the voltage of the power battery drops back to the preset stable state;

[0052] Substitute U, t1 and t2 into the charging condition energy formula to calculate the terminal charging condition energy W e ;

[0053] Execution steps: Perform a discharge test on the power battery in a high-loss state;

[0054] The power battery is charged with a second preset current I2 until the voltage of the power battery reaches a preset mid-value voltage U mid , where U mid =(U low +U up ) / 2;

[0055] Stop charging and control the electric vehicle where the power battery in the high-loss state is located to stand for a second preset time τ2 until the voltage of the power battery drops back to the preset stable state;

[0056] The power battery is charged with a third preset current I3 until the voltage of the power battery reaches U mid ;

[0057] Stop charging and control the electric vehicle where the power battery in the high-loss state is located to stand for a third preset time τ3 until the voltage of the power battery drops back to the preset stable state;

[0058] Calculate the stable power battery voltage and U mid The absolute value of the difference;

[0059] Determine whether the absolute value of the difference is less than the preset stable voltage value U of the power battery s ;

[0060] Determine that the absolute value of the difference is less than the preset stable voltage value U of the power battery s , record the voltage U of the power battery mid1 ;

[0061] The power battery is continuously charged at I2, and the voltage U of the power battery after the fourth preset time τ4 is recorded. mid2 ;

[0062] Will U mid1 、U mid2 Substitute I2 into the charging condition DC resistance formula to calculate the terminal charging condition DC resistance R e .

[0063] In one embodiment, the power battery in the medium loss state is subjected to a discharge test and a charge test to obtain the driving stage charging condition energy W of the power battery. r And the DC resistance R of the charging condition during the driving stage r The steps include:

[0064] The electric vehicle in which the power battery in the medium-loss state is located is controlled to travel at a preset speed v to discharge the power battery until the voltage of the power battery reaches a preset cut-off discharge voltage U low ;

[0065] Controlling the electric vehicle in which the power battery in the medium-loss state is located to stand for a first preset time τ1 until the voltage of the power battery is in a preset stable state;

[0066] The power battery is charged with a first preset current I1 until the voltage of the power battery reaches a preset cut-off charging voltage U up ;

[0067] Record the real-time charging voltage U, the starting charging time t1 and the ending charging time t2 during the charging process;

[0068] Stop charging and control the electric vehicle where the power battery in the medium-loss state is located to stand for a second preset time τ2 until the voltage of the power battery drops back to the preset stable state;

[0069] Substitute U, t1 and t2 into the charging condition energy formula to calculate the driving stage charging condition energy W r ;

[0070] Execution steps: Perform a discharge test on a power battery in a medium-loss state;

[0071] The power battery is charged with a second preset current I2 until the voltage of the power battery reaches a preset mid-value voltage U mid , where U mid =(U low +U up ) / 2;

[0072] Stop charging and control the electric vehicle where the power battery in the medium-loss state is located to stand for a second preset time τ2 until the voltage of the power battery drops back to the preset stable state;

[0073] The power battery is charged with a third preset current I3 until the voltage of the power battery reaches U mid ;

[0074] Stop charging and control the electric vehicle where the power battery in the medium-loss state is located to stand for a third preset time τ3 until the voltage of the power battery drops back to the preset stable state;

[0075] Calculate the stable power battery voltage and U mid The absolute value of the difference;

[0076] Determine whether the absolute value of the difference is less than the preset stable voltage value U of the power battery s ;

[0077] Determine that the absolute value of the difference is less than the preset stable voltage value U of the power battery s , record the voltage U of the power battery mid1 ;

[0078] The power battery is continuously charged at I2, and the voltage U of the power battery after the fourth preset time τ4 is recorded. mid2 ;

[0079] Will U mid1 、U mid2 Substitute I2 into the charging condition DC resistance formula to calculate the driving stage charging condition DC resistance R r .

[0080] In addition, to achieve the above-mentioned purpose, the present application also provides an electric vehicle remaining performance evaluation device, which includes: a memory, a processor, and an electric vehicle remaining performance evaluation program stored on the memory and capable of running on the processor. When the electric vehicle remaining performance evaluation program is executed by the processor, the steps of the electric vehicle remaining performance evaluation method as described above are implemented.

[0081] In addition, to achieve the above-mentioned purpose, the present application also provides a computer-readable storage medium, on which an electric vehicle remaining performance evaluation program is stored. When the electric vehicle remaining performance evaluation program is executed by a processor, the steps of the electric vehicle remaining performance evaluation method as described above are implemented.

[0082] The present application proposes a method, device and computer-readable storage medium for evaluating the remaining performance of an electric vehicle, wherein the method for evaluating the remaining performance of an electric vehicle performs discharge tests and charge tests on the power batteries of the electric vehicle in different preset loss states to obtain the charging condition energy and charging condition DC resistance of the power batteries; performs calculations based on the charging condition energy and charging condition DC resistance to obtain the charging condition energy decay rate and charging condition DC resistance expansion of the electric vehicle; performs calculations based on the charging condition energy decay rate and charging condition DC resistance expansion and the mileage traveled by the electric vehicle to obtain the health status and remaining mileage of the electric vehicle in its life cycle; under the guarantee of rigorous data acquisition and calculation processes, an efficient and reliable evaluation of the remaining performance of the electric vehicle is achieved, the evaluation cost consumed in the evaluation process is effectively controlled, and the problem that the health status of the electric vehicle's on-board power battery cannot be quickly and accurately evaluated is avoided. BRIEF DESCRIPTION OF THE DRAWINGS

[0083] FIG1 is a schematic diagram of a terminal structure of a hardware operating environment involved in an embodiment of the present application;

[0084] FIG2 is a flow chart of a first embodiment of a method for evaluating residual performance of an electric vehicle according to the present invention;

[0085] FIG3 is a schematic diagram of a detailed process of step S10 in FIG2 ;

[0086] FIG4 is a schematic diagram of the hardware environment for performing an accelerated cycle life test of a power battery under vibration heating conditions in this application;

[0087] FIG5 is a schematic diagram of a scenario of an accelerated aging test of a power battery cycle life under vibration and high temperature conditions in a second embodiment of the electric vehicle residual performance evaluation method of the present application;

[0088] FIG6 is a schematic diagram of a decay curve of the charge and discharge capacity of a power battery versus the number of charge and discharge cycles under vibration and high temperature conditions in the second embodiment of the electric vehicle residual performance evaluation method of the present application.

[0089] The realization of the objectives, functional features and advantages of this application will be further explained in conjunction with embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0090] It should be understood that the specific embodiments described herein are only used to explain the present application and are not intended to limit the present application.

[0091] The main solution of the embodiment of the present application is: a method for evaluating the remaining performance of an electric vehicle, the method comprising the following steps:

[0092] Performing discharge tests and charge tests on power batteries of electric vehicles at different preset loss states to obtain charging condition energy and charging condition DC resistance of the power batteries;

[0093] Calculating according to the charging condition energy and the charging condition DC resistance to obtain the charging condition energy attenuation rate and the charging condition DC resistance expansion of the electric vehicle;

[0094] The health of the electric vehicle and the remaining mileage in its life cycle are calculated based on the energy attenuation rate and DC resistance expansion degree of the charging condition and the mileage that the electric vehicle has traveled.

[0095] With the increasing popularity of electric vehicles, the safety and durability of their onboard power batteries are attracting increasing attention. Regarding safety, most electric vehicle accidents stem from the explosion of aging power batteries. Therefore, quickly and accurately assessing the health of electric vehicle power batteries is extremely important. However, the industry currently lacks an authoritative, cost-effective, and rapid assessment method for the residual performance of electric vehicles.

[0096] The present application provides a method for evaluating the remaining performance of an electric vehicle. The method performs discharge tests and charge tests on power batteries of the electric vehicle in different preset loss states to obtain the charging condition energy and charging condition DC resistance of the power batteries; performs calculations based on the charging condition energy and charging condition DC resistance to obtain the charging condition energy decay rate and charging condition DC resistance expansion of the electric vehicle; performs calculations based on the charging condition energy decay rate and charging condition DC resistance expansion and the mileage traveled by the electric vehicle to obtain the health status and remaining mileage of the electric vehicle during its life cycle; and with the guarantee of rigorous data acquisition and calculation processes, an efficient and reliable evaluation of the remaining performance of the electric vehicle is achieved, the evaluation cost consumed in the evaluation process is effectively controlled, and the problem of the inability to quickly and accurately evaluate the health status of the electric vehicle's on-board power battery is avoided.

[0097] As shown in FIG1 , FIG1 is a schematic diagram of the terminal structure of the hardware operating environment involved in the embodiment of the present application.

[0098] The terminal in the embodiment of the present application can be a PC, or it can be a terminal device such as a tablet computer, a portable computer, etc. that has display function, network connection function and data calculation function.

[0099] As shown in Figure 1, the terminal may include: a processor 1001, such as a CPU, a network interface 1004, a user interface 1003, a memory 1005, and a communication bus 1002. Among them, the communication bus 1002 is used to realize the connection and communication between these components. The user interface 1003 may include a display screen (Display), an input unit such as a keyboard (Keyboard), and the user interface 1003 may also include a standard wired interface and a wireless interface. The network interface 1004 may optionally include a standard wired interface and a wireless interface (such as a WI-FI interface). The memory 1005 may be a high-speed RAM memory or a stable memory (non-volatile memory), such as a disk memory. The memory 1005 may also be a storage device independent of the aforementioned processor 1001.

[0100] In one embodiment, the terminal may also include a camera, an RF (Radio Frequency) circuit, a sensor, an audio circuit, a WiFi module, and the like. Among them, the sensors include light sensors, motion sensors, and other sensors. Specifically, the light sensor may include an ambient light sensor and a proximity sensor, wherein the ambient light sensor may adjust the brightness of the display screen according to the brightness of the ambient light, and the proximity sensor may turn off the display screen and / or backlight when the mobile terminal is moved to the ear. As a type of motion sensor, the gravity acceleration sensor can detect the magnitude of acceleration in all directions (generally three axes), and can detect the magnitude and direction of gravity when stationary. It can be used for applications that identify the posture of the mobile terminal (such as horizontal and vertical screen switching, related games, magnetometer posture calibration), vibration recognition related functions (such as pedometer, tapping), etc.; of course, the mobile terminal may also be configured with other sensors such as gyroscopes, barometers, hygrometers, thermometers, infrared sensors, etc., which will not be repeated here.

[0101] Those skilled in the art will understand that the terminal structure shown in FIG1 does not constitute a limitation on the terminal, and may include more or fewer components than shown, or a combination of certain components, or a different arrangement of components.

[0102] As shown in FIG1 , the memory 1005 as a computer storage medium may include an operating system, a network communication module, a user interface module, and an electric vehicle remaining performance evaluation program.

[0103] In the terminal shown in FIG1 , the network interface 1004 is mainly used to connect to the backend server and perform data communication with the backend server; the user interface 1003 is mainly used to connect to the client (user end) and perform data communication with the client; and the processor 1001 can be used to call the electric vehicle remaining performance evaluation program stored in the memory 1005 and perform the following operations:

[0104] Performing discharge tests and charge tests on power batteries of electric vehicles at different preset loss states to obtain charging condition energy and charging condition DC resistance of the power batteries;

[0105] Calculating according to the charging condition energy and the charging condition DC resistance to obtain the charging condition energy attenuation rate and the charging condition DC resistance expansion of the electric vehicle;

[0106] The health of the electric vehicle and the remaining mileage in its life cycle are calculated based on the energy attenuation rate and DC resistance expansion degree of the charging condition and the mileage that the electric vehicle has traveled.

[0107] Furthermore, the processor 1001 may call the electric vehicle remaining performance evaluation program stored in the memory 1005 and perform the following operations:

[0108] The step of performing a discharge test and a charge test on the power battery of the electric vehicle in different preset loss states to obtain the charging condition energy and the charging condition DC resistance of the power battery includes:

[0109] Perform discharge test and charge test on the power battery in low loss state to obtain the initial charging condition energy W of the power battery. b And the DC resistance R of the initial charging condition b ;

[0110] Perform discharge test and charge test on the power battery in high loss state to obtain the terminal charging condition energy W of the power battery. e and the DC resistance R of the terminal charging condition e ;

[0111] Perform discharge test and charge test on the power battery in the medium loss state to obtain the driving stage charging condition energy W of the power battery. r And the DC resistance R of the charging condition during the driving stage r .

[0112] Furthermore, the processor 1001 may call the electric vehicle remaining performance evaluation program stored in the memory 1005 and perform the following operations:

[0113] The step of calculating based on the charging condition energy and the charging condition DC resistance to obtain the charging condition energy attenuation rate and the charging condition DC resistance expansion of the electric vehicle includes:

[0114] W b 、W e and W r Substitute into the energy decay rate formula of charging condition to calculate the energy decay rate of charging condition

[0115] R b 、R e and R r Substitute it into the DC resistance expansion formula under charging condition to calculate the DC resistance expansion under charging condition.

[0116] Furthermore, the processor 1001 may call the electric vehicle remaining performance evaluation program stored in the memory 1005 and perform the following operations:

[0117] The step of calculating the health and remaining mileage of the electric vehicle according to the energy attenuation rate and the DC resistance expansion degree of the charging condition and the mileage of the electric vehicle includes:

[0118] Get the mileage L of the electric vehicle, and and Substitute into the health formula of the electric vehicle for calculation to obtain the health of the electric vehicle

[0119] L, and Substitute into the remaining driving range formula of the electric vehicle's life cycle to calculate the remaining driving range L of the electric vehicle's life cycle. r .

[0120] Furthermore, the processor 1001 may call the electric vehicle remaining performance evaluation program stored in the memory 1005 and perform the following operations:

[0121] The step of performing a discharge test on a power battery in a low-loss state includes:

[0122] The electric vehicle in which the power battery in the low-loss state is located is controlled to travel at a preset speed v to discharge the power battery until the voltage of the power battery reaches a preset cut-off discharge voltage U low ;

[0123] The electric vehicle in which the power battery in the low-loss state is located is controlled to remain stationary for a first preset time τ1 until the voltage of the power battery is in a preset stable state.

[0124] Furthermore, the processor 1001 may call the electric vehicle remaining performance evaluation program stored in the memory 1005 and perform the following operations:

[0125] The step of performing a charging test on the power battery in a low-loss state includes:

[0126] The power battery is charged with a first preset current I1 until the voltage of the power battery reaches a preset cut-off charging voltage U up ;

[0127] Record the real-time charging voltage U, the starting charging time t1 and the ending charging time t2 during the charging process;

[0128] Stop charging and control the electric vehicle where the power battery in the low-loss state is located to stand for a second preset time τ2 until the voltage of the power battery drops back to the preset stable state;

[0129] The initial charging condition energy W of the power battery is obtained b The steps include:

[0130] Substitute U, t1 and t2 into the charging condition energy formula to calculate the initial charging condition energy W b .

[0131] Furthermore, the processor 1001 may call the electric vehicle remaining performance evaluation program stored in the memory 1005 and perform the following operations:

[0132] Execution steps: Perform a discharge test on the power battery in a low-loss state;

[0133] The step of performing a charging test on the power battery in a low-loss state further includes:

[0134] The power battery is charged with a second preset current I2 until the voltage of the power battery reaches a preset mid-value voltage U mid , where U mid =(U low +U up ) / 2;

[0135] Stop charging and control the electric vehicle where the power battery in the low-loss state is located to stand for a second preset time τ2 until the voltage of the power battery drops back to the preset stable state;

[0136] The power battery is charged with a third preset current I3 until the voltage of the power battery reaches U mid ;

[0137] Stop charging and control the electric vehicle where the power battery in the low-loss state is located to stand for a third preset time τ3 until the voltage of the power battery drops back to the preset stable state;

[0138] Calculate the stable power battery voltage and U mid The absolute value of the difference.

[0139] Furthermore, the processor 1001 may call the electric vehicle remaining performance evaluation program stored in the memory 1005 and perform the following operations:

[0140] Determine whether the absolute value of the difference is less than the preset stable voltage value U of the power battery s ;

[0141] Determine that the absolute value of the difference is less than the preset stable voltage value U of the power battery s , record the voltage U of the power battery mid1 ;

[0142] The power battery is continuously charged at I2, and the voltage U of the power battery after the fourth preset time τ4 is recorded. mid2 ;

[0143] The DC resistance R of the power battery at the initial charging condition is obtained. b The steps include:

[0144] Will U mid1 、U mid2 Substitute I2 into the charging condition DC resistance formula to calculate the initial charging condition DC resistance R b .

[0145] 2 , a first embodiment of the present application provides a method for evaluating the remaining performance of an electric vehicle, the method comprising:

[0146] Step S10, performing a discharge test and a charge test on the power batteries of the electric vehicle in different preset loss states to obtain the charging condition energy and the charging condition DC resistance of the power batteries;

[0147] 3 , in this embodiment, step S10 includes:

[0148] Step S11: performing a discharge test and a charge test on the power battery in a low-loss state to obtain the initial charging condition energy W of the power battery. b And the DC resistance R of the initial charging condition b ;

[0149] Step S12: performing a discharge test and a charge test on the power battery in a high loss state to obtain the terminal charging condition energy W of the power battery. e and the DC resistance R of the terminal charging condition e ;

[0150] Step S13: Perform a discharge test and a charge test on the power battery in a medium-loss state to obtain the driving stage charging condition energy W of the power battery. r And the DC resistance R of the charging condition during the driving stage r .

[0151] It should be noted that, in this embodiment, the execution subject is a PC, and the communication connection between the PC and the electric vehicle is used to enable the on-board controller of the electric vehicle to collaboratively implement the various steps of the method, wherein the on-board controller includes but is not limited to VCU (Vehicle Control Unit), OBC (On Board Charger) and BMS (Battery Management System). The different preset loss states include low loss state, high loss state and medium loss state. The power battery can be a lithium battery, or a lead-acid battery, a nickel-metal hydride battery, a sodium-sulfur battery, a secondary lithium battery, an air battery, a ternary lithium battery or other rechargeable batteries with similar characteristics that can be widely used in electric vehicles. The power batteries in the above states all come from electric vehicles of the same model.

[0152] In this embodiment, the power battery in the low-loss state refers to a power battery in a brand-new electric vehicle that has just been manufactured or rolled off the production line and has not yet been used. Therefore, the state of the power battery can be regarded as a lossless state.

[0153] The power battery in the high-loss state is a power battery in an aging diving state. Lithium-ion batteries will gradually age during use and their capacity will gradually decrease. During the aging process of a given battery specification, the capacity decay process can be roughly divided into two stages. In the first stage, the capacity decay is roughly linear with time or the number of cycles; in the second stage, the capacity decay rate suddenly accelerates, and the battery performance decays rapidly. This process is usually called capacity "diving". The turning point between the two stages is called the capacity diving point, and the power battery in the high-loss state is at this turning point.

[0154] 4 , in this scenario, an accelerated cycle life test is performed on the power battery of an electric vehicle under vibration heating conditions by utilizing three integrated test systems, namely, the system consisting of the temperature control equipment, the vibration table, etc. in FIG4 , and the charge and discharge test cabinet. The charge and discharge capacity of the power battery in each charge and discharge cycle is recorded, and a decay curve of the charge and discharge capacity of the power battery versus the number of charge and discharge cycles is plotted and linear fitting is performed. When the charge and discharge capacity of the power battery reaches the diving inflection point of the linear decay curve, the accelerated cycle life test is stopped, and at this time, the power battery in the high-loss state can be obtained.

[0155] The power battery in the medium loss state is a power battery in an electric vehicle in the driving stage, that is, a power battery in an electric vehicle in the normal use stage and the remaining performance of the power battery needs to be evaluated.

[0156] It is understandable that the purpose of the above steps is to collect the corresponding parameters of the power battery in the initial state, aging state and use state, that is, the initial charging condition energy Wb , DC resistance R at the initial charging condition b , terminal charging condition energy W e , DC resistance R at the end of charging condition e , Charging condition energy W during driving phase r And the DC resistance R of the charging condition during the driving stage r .

[0157] In this embodiment, the step of obtaining parameters, taking step S11 as an example, the step of performing a discharge test on the power battery in a low-loss state in step S11 includes:

[0158] Step 1: Control the electric vehicle in which the power battery in the low-loss state is located to travel at a preset speed v, so that the power battery discharges until the voltage of the power battery reaches a preset cut-off discharge voltage U low ; Control the electric vehicle where the power battery in the low-loss state is located to stand for a first preset time τ1 until the voltage of the power battery is in a preset stable state.

[0159] It should be noted that regarding the preset stable state, this embodiment monitors the open-circuit voltage of the power battery in real time. If the voltage does not change within a preset time, it is considered to be in a stable state. The value range of v is 5% to 50% of the vehicle's maximum speed; the value range of τ1 is 30 minutes to 5 hours.

[0160] In step S11, a charging test is performed on the power battery in a low-loss state to obtain the initial charging condition energy W of the power battery. b The steps include:

[0161] Step 2: Charge the power battery with a first preset current I1 until the voltage of the power battery reaches a preset cut-off charging voltage U up ; Record the real-time charging voltage U, the starting charging time t1 and the ending charging time t2 during the charging process; stop charging and control the electric vehicle where the power battery in the low-loss state is located to stand for a second preset time τ2 until the voltage of the power battery drops back to the preset stable state; substitute U, t1 and t2 into the charging condition energy formula to calculate to obtain the starting charging condition energy W b .

[0162] It should be noted that the value range of I1 is 0.05C~1C; 1C represents the full power of the power battery, and 0.05C represents 5% of the power of the power battery; the value range of τ2 is 3min~1h; the energy formula of the charging condition is

[0163] Step 3: Repeat step 1 above;

[0164] The step of performing a charging test on the power battery in the low-loss state in step S11 further includes:

[0165] Step 4: Charge the power battery with a second preset current I2 until the voltage of the power battery reaches a preset mid-value voltage U mid , where U mid =(U low +U up ) / 2; stop charging and control the electric vehicle where the power battery in the low-loss state is located to stand for a second preset time τ2 until the voltage of the power battery drops back to the preset stable state;

[0166] Step 5: Charge the power battery with a third preset current I3 until the voltage of the power battery reaches U mid Stop charging and control the electric vehicle where the power battery in the low-loss state is located to stand for a third preset time τ3 until the voltage of the power battery drops back to the preset stable state; calculate the stable power battery voltage and U mid The absolute value of the difference.

[0167] It should be noted that the value range of I2 is 0.05C~1C; the value range of I3 is 0.01C~0.1C; the value range of τ3 is 1min~10min.

[0168] After obtaining the absolute value of the difference, the following steps need to be performed first:

[0169] Step 6: Determine whether the absolute value of the difference is less than the preset stable voltage value U of the power battery s In response to the absolute value of the difference being greater than the preset stable voltage value U of the power battery s , continue to enter steps five and six; in response to the absolute value of the difference being less than the preset stable voltage value U of the power battery s , go to step seven.

[0170] It should be noted that, among them, U s The value range is 0.1% to 2% of the rated voltage of the power battery.

[0171] Step 7: Record the voltage U of the power battery mid1 I2 to continue charging the power battery, record the fourth preset time τ4 after the power battery voltage U mid2 ;Change U mid1 、U mid2 Substitute I2 into the charging condition DC resistance formula to calculate the initial charging condition DC resistance R b .

[0172] It should be noted that the value range of τ4 is 1s to 60s, and the DC resistance formula of the charging condition is:

[0173] At this point, all the parameters required to be obtained in step S11 have been obtained, and the corresponding parameters in step S12 and step S13 can be obtained by referring to the above steps 1 to 7.

[0174] Step S20, calculating based on the charging condition energy and the charging condition DC resistance to obtain the charging condition energy attenuation rate and the charging condition DC resistance expansion of the electric vehicle;

[0175] In this embodiment, step S20 includes:

[0176] W b 、W e and W r Substitute into the energy decay rate formula of charging condition to calculate the energy decay rate of charging condition

[0177] R b 、R e and R r Substitute it into the DC resistance expansion formula under charging condition to calculate the DC resistance expansion under charging condition.

[0178] It is understandable that W has been obtained through the above steps. b 、W e and W r and R b 、R e and R r , which only needs to be used for calculation.

[0179] It should be noted that the energy decay rate formula for the charging condition is: The DC resistance expansion formula for the charging condition is:

[0180] Step S30 , calculating based on the energy attenuation rate and DC resistance expansion degree of the charging condition and the mileage of the electric vehicle to obtain the health of the electric vehicle and the remaining mileage of its life cycle.

[0181] In this embodiment, step S30 includes:

[0182] Get the mileage L of the electric vehicle, and and Substitute into the health formula of the electric vehicle for calculation to obtain the health of the electric vehicle

[0183] L, and Substitute into the remaining driving range formula of the electric vehicle's life cycle to calculate the remaining driving range L of the electric vehicle's life cycle. r .

[0184] It can be understood that the mileage L of the electric vehicle corresponds to the electric vehicle in which the power battery in the medium wear state in the above step S13 is located.

[0185] It should be noted that the health formula of the electric vehicle is: in,

[0186] The formula for the remaining mileage of the electric vehicle during its life cycle is:

[0187] In this embodiment, three integrated test systems and a charge-discharge test cabinet are used to perform accelerated aging tests on power batteries under vibration and high-temperature conditions, enabling rapid and accurate identification of power batteries in high-loss states, providing a basis for comparison. A charging method using an electric vehicle's built-in controller to control current allows for rapid testing of the charging condition energy and DC internal resistance, simplifying the testing process and improving testing efficiency. An algorithm is provided for measuring the health of an electric vehicle's power battery using the energy decay rate and the maximum expansion value of the DC internal resistance under charging conditions. An algorithm is also provided for measuring the remaining range of an electric vehicle's life cycle using the energy decay rate and the maximum expansion value of the DC internal resistance under charging conditions. A corresponding algorithm based on the health of the electric vehicle and its remaining range over its life cycle is also provided. The charging condition energy and DC resistance of power batteries of the same electric vehicle in three different loss states obtained through steps one to seven are used to accurately assess the remaining performance of the power battery of an electric vehicle in the driving phase using the aforementioned algorithm, providing the industry with an authoritative, low-cost, and rapid method for assessing the remaining performance of electric vehicles.

[0188] Furthermore, taking the Baojun E100 pure electric vehicle model already on the market of SAIC-GM-Wuling as an example, a second embodiment of the electric vehicle residual performance evaluation method of the present application is proposed. Based on the embodiment shown in FIG2 above, this embodiment includes:

[0189] First, a newly rolled-off Baojun E100 electric vehicle was driven at room temperature at a speed below 30 km / h, draining its power battery to a set discharge cutoff voltage of 86.5V. The vehicle was then left to stand for more than 3 hours until the open-circuit voltage of the power battery reached a stable state. The vehicle's BMS, OBC, and VCU were then used to jointly control the charging of the electric vehicle's power battery at a current of 16A to a charge cutoff voltage of 128.5V. The battery was then left to stand for more than 30 minutes to allow the power battery voltage to return to a stable state. The BMS was used to record the real-time charging voltage, start charging time, and end charging time during the charging process, and the starting charging condition energy W of the electric vehicle at room temperature was calibrated. b =15.23kWh;

[0190] The electric vehicle is discharged again at a low speed to a cut-off discharge voltage of 86.5V and allowed to stand until it reaches a stable state. The vehicle-mounted controller BMS, OBC and VCU are used to jointly control the electric vehicle's power battery to be charged with a current of 16A to a median voltage of 107.5V. The power battery is allowed to stand until the voltage drops to a stable state. Subsequently, the electric vehicle's power battery is slowly charged with a small current of 2A to 107.5V and allowed to stand for more than 5 minutes to allow the power battery voltage to drop to a stable state. The absolute value of the difference between the stabilized power battery voltage and 107.5V is calculated. If the absolute value of the difference is greater than 0.5V, the 2A small current charging operation is repeated until the absolute value of the difference is less than or equal to 0.5V. The power battery voltage U at this time is recorded. mid1 The voltage U of the power battery is 107.30V. The electric vehicle is charged for 10s at a constant current of 16A. The voltage U of the power battery is recorded after 10s. mid2 The DC resistance of the power battery at the start of charging at room temperature for 10 seconds and 16A is 107.81V.

[0191] Subsequently, the Baojun E100 pure electric vehicle power battery was subjected to vibration testing (according to the method 6.3.11 of GB / T 34816-2015 "Electrical Performance Requirements and Test Methods for Power Batteries for Electric Vehicles") and accelerated aging testing of the power battery cycle life under high temperature (60°C) conditions (Figure 5). The decay curve of the power battery charge and discharge capacity versus the number of charge and discharge cycles (Figure 6) and the diving inflection point (at 1430 cycles) were obtained. Referring to the above steps, the terminal charging condition energy W at the diving inflection point of the decay curve was measured. e And the DC resistance R of the terminal charging condition e The values ​​of W are calculated respectively. e =9.91kWh, R e =60mΩ;

[0192] Finally, the Baojun E100 electric vehicle that has traveled a certain mileage (L = 64185km) was tested for the charging condition energy W of the electric vehicle during the driving phase according to the above method. r And the DC resistance R of the charging condition during the driving phase r , calculate W r =14.11kWh, R r =40mΩ;

[0193] Calculate the energy attenuation rate of the electric vehicle under charging conditions And DC resistance expansion under charging conditions

[0194]

[0195]

[0196] Calculate the health of the electric vehicle and the remaining mileage L in the life cycle r :

[0197]

[0198]

[0199]

[0200] In this embodiment, the electric vehicle remaining performance evaluation method provided in the first embodiment is applied to a specific vehicle model that has been put into use. Through intuitive test data and calculation data, the health status and remaining driving range of the Baojun E100 electric vehicle that has traveled a certain mileage (L=64185km) are demonstrated, effectively demonstrating the characteristics of the electric vehicle remaining performance evaluation method provided in the first embodiment, such as speed, reliability, efficiency, and practicality.

[0201] In addition, an embodiment of the present application also proposes a computer-readable storage medium, on which an electric vehicle remaining performance evaluation program is stored. When the electric vehicle remaining performance evaluation program is executed by a processor, the steps of the electric vehicle remaining performance evaluation method in the above-mentioned embodiments are implemented.

[0202] It should be noted that, in this document, the terms "comprises," "includes," or any other variations thereof are intended to encompass non-exclusive inclusion, such that a process, method, article, or system comprising a series of elements includes not only those elements but also other elements not explicitly listed, or elements inherent to such process, method, article, or system. In the absence of further limitations, an element defined by the phrase "comprising a ..." does not exclude the presence of other identical elements in the process, method, article, or system comprising the element.

[0203] The serial numbers of the above-mentioned embodiments of the present application are for description only and do not represent the advantages or disadvantages of the embodiments.

[0204] Through the description of the above implementation methods, those skilled in the art can clearly understand that the above-mentioned embodiment methods can be implemented by means of software plus the necessary general hardware platform, and of course can also be implemented by hardware, but in many cases the former is a better implementation method. Based on this understanding, the technical solution of the present application, or the part that contributes to the prior art, can be embodied in the form of a software product, which is stored in a storage medium (such as ROM / RAM, magnetic disk, optical disk) as described above, and includes a number of instructions for enabling a terminal device (which can be a mobile phone, computer, server, air conditioner, or network device, etc.) to execute the methods described in each embodiment of the present application.

[0205] The above are merely optional embodiments of the present application and do not limit the patent scope of the present application. Any equivalent structure or equivalent process transformation made using the contents of the present application specification and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present application.

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