Electric vehicle power battery switch disconnection control method, device and storage medium

Abstract

The present invention discloses a method, computer device, and storage medium for controlling the disconnection of a power battery switch in an electric vehicle. By determining the disconnection moment based on an operating current drop curve and a life curve, and disconnecting the switch device at that moment, the present invention can control the operating current of the electric vehicle to decrease at a matching rate based on the severity of the fault in the event of a fault in the electric vehicle, thereby reducing the impact of sudden current changes on the switch device. This helps to ensure the power demand of the electric vehicle while avoiding greater dangers caused by the fault. Furthermore, the change in the operating current flowing through the switch device can be matched with the change in the remaining life of the switch device, making it easier to plan maintenance or replacement of the switch device, thereby reducing consumption caused by improper use of the switch device while ensuring the safety of the electric vehicle. The present invention has wide application in the field of electric vehicle technology.

Description

Technical Field

[0001] The present invention relates to the technical field of electric vehicles, and in particular to a method for controlling the disconnection of a power battery switch of an electric vehicle, a computer device, and a storage medium. Background Art

[0002] The power battery in an electric vehicle primarily powers the motor, but can also be used to power high-voltage accessories such as the onboard compressor, heater, and DC-DC power supply. When an electric vehicle encounters a fault, disconnecting the power battery from the motor and other high-voltage accessories is necessary for safety. Therefore, a switch device is typically installed between the power battery and these loads.

[0003] While current technology allows for the timely disconnection of switching devices, severing the connection between the power battery and the load, the sudden disconnection of the switching device can cause significant current fluctuations in the circuit, potentially impacting the power battery, circuit, and load, potentially damaging these components. Because the switching device carries large current values and significant current fluctuations, it bears the brunt of these impacts. If the switching device is damaged by the sudden switching, it can easily affect the power supply and operation of the entire vehicle, potentially posing further risks such as fire. Summary of the Invention

[0004] In view of the technical problems in current electric vehicle technology, such as the risk of damage to switching devices due to the impact of sudden disconnection and the possibility of further dangerous incidents, the purpose of the present invention is to provide a disconnection control method, computer device and storage medium for electric vehicle power battery switches.

[0005] In one aspect, an embodiment of the present invention includes a method for controlling the disconnection of a power battery switch of an electric vehicle, the method comprising the following steps:

[0006] Identify the fault level of electric vehicles;

[0007] According to the fault level, a corresponding operating current drop curve is matched; the operating current drop curve is used to represent the corresponding relationship between the operating current of the electric vehicle and time when adapted to the fault level;

[0008] Obtaining a life curve of a switching device of a power battery of an electric vehicle; the life curve is used to represent a corresponding relationship between the off current and the life of the switching device;

[0009] determining a cut-off time according to the operating current drop curve and the life curve;

[0010] At the turn-off timing, the switching device is turned off.

[0011] Furthermore, matching a corresponding operating current drop curve according to the fault level includes:

[0012] When the fault level is the first level, the working current drop curve is set to be

[0013] When the fault level is the second level, the operating current drop curve is set to

[0014] When the fault level is the third level, the operating current drop curve is set to be in the form of I(t)=kt+I0;

[0015] Among them, the fault severity represented by the first level, second level and third level decreases in sequence, I represents current, t represents time, U represents the bus voltage which is a constant, R1(t) represents the equivalent internal resistance of the electric vehicle's motor that changes with time in the ASC active short-circuit mode, R2(t) represents the equivalent internal resistance of the electric vehicle's high-voltage accessories that changes with time in the ASC active short-circuit mode, R3 represents the internal resistance of the power battery which is a constant, I1 represents the zero-torque point offset consumption current of the electric vehicle's motor, U(t) represents the bus voltage that changes with time in the zero-torque mode of the electric vehicle's motor, and k and I0 represent constant coefficients.

[0016] Furthermore, determining the cut-off time according to the operating current drop curve and the life curve includes:

[0017] Determining a safe cut-off current value according to the life curve;

[0018] According to the working current drop curve, the time corresponding to the safety cut-off current value is queried as the cut-off moment.

[0019] Furthermore, determining the cut-off time according to the operating current drop curve and the life curve includes:

[0020] Mapping the operating current drop curve and the life curve to the same coordinate system;

[0021] The time corresponding to the position where the similarity between the operating current drop curve and the life curve is the greatest is used as the cut-off moment.

[0022] Furthermore, the time corresponding to the position where the similarity between the working current drop curve and the life curve is the greatest is used as the cut-off moment, including:

[0023] Performing a derivative operation of current with respect to time or a derivative operation of time with respect to current on the mapped working current drop curve to obtain a first derivative curve;

[0024] Performing a derivative operation of current with respect to time or a derivative operation of time with respect to current on the mapped life curve to obtain a second derivative curve;

[0025] Calculating the difference between the first derivative curve and the second derivative curve at corresponding points to obtain a third derivative curve;

[0026] The time corresponding to the minimum value in the third derivative curve is determined as the cut-off time.

[0027] Furthermore, the time corresponding to the position where the similarity between the working current drop curve and the life curve is the greatest is used as the cut-off moment, including:

[0028] Performing segmented similarity calculation on the mapped working current drop curve and the life curve to obtain similarity of each corresponding segment;

[0029] The time corresponding to the maximum value among the similarities is determined as the cutting time.

[0030] Furthermore, the electric vehicle power battery switch cut-off control method further includes:

[0031] Obtaining the instantaneous current of the switching device at the cut-off moment;

[0032] comparing the instantaneous current with the life curve;

[0033] When the comparison result reaches the maintenance recommendation threshold, a maintenance prompt message is generated.

[0034] Furthermore, the electric vehicle power battery switch cut-off control method further includes:

[0035] The maintenance prompt information is pushed to the user terminal and / or server.

[0036] On the other hand, an embodiment of the present invention also includes a computer device including a memory and a processor, the memory being used to store at least one program, and the processor being used to load at least one program to execute a method for controlling the disconnection of a power battery switch of an electric vehicle in an embodiment.

[0037] On the other hand, an embodiment of the present invention further includes a storage medium storing a program executable by a processor. When the program is executed by the processor, it is used to execute a method for controlling the disconnection of a power battery switch of an electric vehicle in an embodiment.

[0038] The beneficial effects of the present invention are as follows: the electric vehicle power battery switch cut-off control method in the embodiment determines the cut-off moment according to the working current drop curve and the life curve, and cuts off the switch device at the cut-off moment. In the event of a fault in the electric vehicle, the working current of the electric vehicle can be controlled to drop at a matching rate according to the severity of the fault, thereby reducing the impact caused by the sudden change in current on the switch device, which is beneficial to ensuring the power demand of the electric vehicle while avoiding greater danger caused by the fault. It can also match the change in the magnitude of the working current flowing through the switch device with the change in the remaining life of the switch device, so that even when the switch device is impacted by a sudden change in current, the actual service life of the switch device is maintained within the design, production and maintenance plan of the switch device, thereby making it easier to plan the maintenance or replacement of the switch device, and reduce the consumption caused by improper use of the switch device while ensuring the safety of the electric vehicle. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 Schematic diagram of a system to which a method for controlling the disconnection of a power battery switch of an electric vehicle can be applied in an embodiment;

[0040] Figure 2 Schematic diagram of the steps of the method for controlling the disconnection of the power battery switch of an electric vehicle in an embodiment;

[0041] Figure 3 A schematic diagram of a lifespan curve in an embodiment;

[0042] Figure 4 is another schematic diagram of the life curve in the embodiment;

[0043] Figure 5 Schematic diagram of the principle of determining the similarity between the corresponding segments of the working current drop curve and the life curve in the embodiment. DETAILED DESCRIPTION

[0044] In this embodiment, the electric vehicle power battery switch cut-off control method can be applied to Figure 1 In the car system shown. Figure 1 In the figure, MOT stands for Motor, TSU stands for Telematics Unit, and RTM stands for Real Time Monitoring. The telematics unit, real-time monitoring module, and power domain controller can be integrated together.

[0045] Reference Figure 1 The power battery is composed of multiple battery cells. A switching device is provided between the power battery and loads such as the motor MOT. Relays are usually used as switching devices, and IGBTs and other devices can also be used as switching devices. Figure 1 High-voltage accessories such as the compressor, heater, and DC-DC power supply are omitted, and each high-voltage accessory can be connected in parallel with the motor MOT, so that when the switch device is closed, the power battery supplies power to each high-voltage accessory and the motor MOT.

[0046] Reference Figure 1 Each battery cell is configured with a collector, and there are n collectors in total, including collector 1, collector 2, ... collector n. Each collector is used to collect status information such as the voltage and temperature of the corresponding battery cell, and send the status information to the power domain controller through a wireless communication protocol, so that the power domain controller can collect the status information of each battery cell. The power domain controller determines whether the electric vehicle has a fault based on the status information and the sensor information such as vehicle speed, engine speed, acceleration, tire pressure, collision, etc. collected from various sensors installed on the electric vehicle. When it is determined that the electric vehicle has a fault, the power domain controller can execute the various steps of the electric vehicle power battery switch cut-off control method.

[0047] Figure 1 The system shown can be installed in a four-wheeled electric vehicle or a two-wheeled electric bicycle, that is, the power domain controller executes the cut-off control method of the electric vehicle power battery switch, which can be applied to four-wheeled electric vehicles, two-wheeled electric bicycles or other types of electric vehicles.

[0048] In this embodiment, refer to Figure 2 , the electric vehicle power battery switch cut-off control method includes the following steps:

[0049] S1. Identify the fault level of the electric vehicle;

[0050] S2. Match the corresponding operating current drop curve according to the fault level;

[0051] S3 obtains the life curve of the switching device of the electric vehicle power battery;

[0052] S4. Determine the cut-off time based on the operating current drop curve and the life curve;

[0053] S5. At the cut-off moment, the switching device is cut off.

[0054] In step S1, the power domain controller determines whether the electric vehicle has experienced a fault based on the status information of each battery cell and the sensor information. If a fault is determined to have occurred, the controller determines the fault level. Specifically, the fault level may be determined as level 1, level 2, or level 3, with different levels representing different fault severity levels. For example, level 1 may indicate a fault such as a collision between the electric vehicle and another vehicle or obstacle. This fault may cause physical damage to the power battery or load, potentially posing a fire hazard within a short period of time, and is the most severe fault. Level 2 may indicate a fault such as the voltage of a portion of the power battery cells being too low, preventing them from discharging externally. This fault may be caused by internal damage to the battery cells and is difficult to recover from within a short period of time, affecting the power battery's power supply performance. This is a moderate fault, indicating a lower severity level than level 1. Level 3 may indicate a fault such as the power battery temperature being too high, temporarily preventing the power battery from discharging externally. This fault may be caused by prolonged, high-current discharge from the power battery, and can recover from itself within a short period of time, indicating a lower severity level than level 2.

[0055] In step S2, the power domain controller selects a corresponding operating current reduction curve based on the specific value of the fault level. For example, if the fault level is level 1, the power domain controller selects a matching operating current reduction curve; if the fault level is level 2, the power domain controller selects another matching operating current reduction curve.

[0056] The operating current drop curve shows the relationship between an electric vehicle's operating current and time. Specifically, the operating current of an electric vehicle can be the sum of the operating currents of loads such as the motor and high-voltage accessories. Ignoring factors such as losses, this is equivalent to the external discharge current of the power battery. The operating current drop curve indicates the negative correlation between the operating current and time. In other words, the operating current of the electric vehicle decreases over time, thereby meeting the operating current reduction requirement for the corresponding fault severity level.

[0057] In this embodiment, when the power domain controller performs step S2, that is, the step of matching the corresponding working current drop curve according to the fault level, it can specifically perform the following steps:

[0058] S201. When the fault level is the first level, the working current drop curve is set to

[0059] S202. When the fault level is the second level, the working current drop curve is set to

[0060] S203. When the fault level is the third level, the operating current drop curve is set to be in the form of I(t)=kt+I0.

[0061] In the formulas in steps S201-S203, I represents current, t represents time, U represents the bus voltage which is a constant, R1(t) represents the equivalent internal resistance of the electric vehicle's motor that changes with time in the ASC active short-circuit mode, R2(t) represents the equivalent internal resistance of the electric vehicle's high-voltage accessories that changes with time in the ASC active short-circuit mode, R3 represents the internal resistance of the power battery which is a constant, I1 represents the zero-torque point offset consumption current of the electric vehicle's motor, U(t) represents the bus voltage that changes with time in the electric vehicle's motor in zero-torque mode, and k and I0 represent constant coefficients.

[0062] In step S201, when the fault level is the first level, that is, the most serious fault occurs, the power domain controller can control the motor to enter the ASC active short-circuit mode for emergency shutdown. At this time, the equivalent internal resistance R1(t) of the motor increases rapidly, while the equivalent internal resistance R2(t) of the high-voltage accessories can increase at a rate slower than R1(t). The internal resistance R3 of the power battery can take a constant value. The motor and the high-voltage accessories are connected in parallel to the power supply bus of the power battery. In this case, the bus voltage U can take a constant value, and the current of the power supply bus (ignoring factors such as loss, equivalent to the external power supply current of the power battery) is expressed as

[0063]

[0064] In step S202, when the fault level is the second level, that is, a medium-severity fault occurs, the power domain controller can control the motor to enter the zero torque mode. In this case, the working current of the motor is the zero torque point offset consumption current I1, where I1 is a constant value, and the voltage on the bus can be expressed as U(t) over time. The working current of the high-voltage accessories is The current consumed by the internal resistance of the power battery is The current of the power supply bus is expressed as

[0065] In step S203, when the fault level is the third level, that is, the mildest fault occurs, the power domain controller can operate in a linear power reduction mode, that is, controlling the working current of the electric vehicle to decrease linearly according to time, expressed as I(t)=kt+I0.

[0066] By executing steps S201-S203, when a fault occurs in the electric vehicle, the operating current of the electric vehicle can be controlled to decrease at a matching rate according to the severity of the fault, thereby helping to ensure the power demand of the electric vehicle while avoiding greater danger caused by the fault.

[0067] The power domain controller can pre-store the life curve of the switching device. The life curve can show the corresponding relationship between the off current and the life of the switching device.

[0068] A form of life curve is Figure 3 As shown, it represents the length of time the switching device can be used continuously if it is turned off at a specific turn-off current each time.

[0069] Another form of the life curve is Figure 4 As shown in , it represents the number of times the switch device can normally switch if it is turned off at a specific off current each time. The duration of each switch operation of the switch device can be determined by experimental statistics, that is, the corresponding relationship between the number of normal switches and the duration of continuous use can be established, so as to Figure 4 The life curve shown in the form is converted into Figure 3 Life curve of the form shown.

[0070] In this embodiment, Figure 3 The life curve shown in the figure is used as an example for explanation, that is, the life curve relates the two variables of current and time. The working current drop curve obtained in step S2 also relates the two variables of current and time.

[0071] In this embodiment, when the power domain controller performs step S4, that is, the step of determining the cut-off time according to the working current drop curve and the life curve, the power domain controller may specifically perform the following steps:

[0072] S401A. According to the life curve, determine the safe cut-off current value;

[0073] S402A. According to the working current drop curve, query the time corresponding to the safe cut-off current value as the cut-off time.

[0074] Steps S401A-S402A are the first execution mode of step S4.

[0075] In step S401A, the power domain controller can calculate the difference between the current time and the time when the switching device was first installed on the electric vehicle to determine the service life of the switching device. Then, the service life is subtracted from the planned total service life (fixed value) of the switching device to obtain the target remaining service life of the switching device. The power domain controller searches the service life curve for the current value corresponding to the target remaining service life as the safe cut-off current value. The safe cut-off current value indicates that if the switching device is cut off at this current, then the remaining service life of the switching device is expected to reach the target remaining service life, and therefore it is a safe current value.

[0076] In step S402A, the power domain controller searches the operating current drop curve I(t) to find out the time corresponding to the safe cut-off current value as the cut-off time.

[0077] The principle of executing steps S401A-S402A is that the switching device is triggered to cut off at the cut-off moment determined in step S402A, and the working current when the switching device is cut off is the safe cut-off current value obtained in step S401A, which can make the remaining service life of the switching device reach the target remaining service life, reduce the negative impact of the current change shock on the service life of the switching device, and help the actual service life of the switching device to be maintained within the design, production and maintenance plan of the switching device, so that it is easier to plan the maintenance or replacement of the switching device, and reduce the consumption caused by improper use of the switching device while ensuring the safety of the electric vehicle.

[0078] In this embodiment, when the power domain controller performs step S4, that is, the step of determining the cut-off time according to the working current drop curve and the life curve, the power domain controller may specifically perform the following steps:

[0079] S401B. Map the operating current drop curve and the life curve to the same coordinate system;

[0080] S402B. The time corresponding to the position where the similarity between the working current drop curve and the life curve is the greatest is used as the cut-off time.

[0081] Steps S401B-S402B are a second execution method of step S4.

[0082] In step S401B, the working current drop curve and the life curve are both linked to the two variables of current and time. However, the scales (intervals) of variables such as current and time may be different in the two curves. For example, the time interval corresponding to the working current drop curve may be from the current time to 10 seconds in the future, while the time interval corresponding to the life curve may be from the current time or a certain time point in the past to one year in the future. This makes it impossible to directly compare the working current drop curve and the life curve. The working current drop curve and the life curve can be directly compared by mapping them to the same coordinate system.

[0083] When executing step S401B, the coordinate system where the working current drop curve is located can be kept unchanged, and the life curve can be mapped to the coordinate system where the working current drop curve is located (or conversely, the coordinate system where the life curve is located can be kept unchanged, and the working current drop curve can be mapped to the coordinate system where the working current drop curve is located). Specifically, the starting point of the life curve can be mapped to the starting point of the working current drop curve, and the end point of the life curve can be mapped to the end point of the working current drop curve, the coefficient of the linear transformation can be determined, and then the coordinate system where the life curve is located can be linearly transformed, so as to linearly map the time interval corresponding to the life curve to the time interval corresponding to the working current drop curve. Similarly, the current interval corresponding to the life curve can be linearly mapped to the current interval corresponding to the working current drop curve.

[0084] When executing step S402B, that is, taking the time corresponding to the position where the working current drop curve has the greatest similarity with the life curve as the cut-off time, the following steps may be specifically performed:

[0085] S402B01A. After mapping the working current drop curve, perform a current-time derivative operation or a time-current derivative operation to obtain a first derivative curve;

[0086] S402B02A. After mapping the life curve, perform a current-time derivative operation or a time-current derivative operation to obtain a second derivative curve;

[0087] S402B03A. Obtain the difference between the first derivative curve and the second derivative curve at corresponding points to obtain the third derivative curve;

[0088] S402B04A. Determine the time corresponding to the minimum value in the third derivative curve as the cut-off time.

[0089] Steps S402B01A-S402B04A are the first execution mode of step S402B. Taking "deriving the current with respect to time" as an example, steps S402B01A-S402B04A are described. The principle of "deriving the time with respect to current" is the same.

[0090] In step S402B01A, a current-time derivative operation is performed on the operating current drop curve I(t) to obtain a first derivative curve I′(t).

[0091] The principle is the same as that of step S402B01A. In step S402B02A, a derivative operation of current with respect to time is performed on the mapped life curve to obtain a second derivative curve.

[0092] After mapping, if the operating current drop curve I(t) and the lifetime curve fall within the same time interval, then the first derivative curve and the second derivative curve also fall within the same time interval. In step S402B03A, the values corresponding to the same time points in the first and second derivative curves are subtracted, and the resulting differences form a third derivative curve. The third derivative curve represents the derivative difference between the operating current drop curve I(t) and the mapped lifetime curve at the same time points.

[0093] In step S402B04A, when the current is derivate with respect to time, the time corresponding to the minimum value (the dimension is actually ampere / second, etc.) is found from the third derivative curve and used as the cut-off time.

[0094] In this embodiment, the principle of executing steps S402B01A-S402B04A is that the third derivative curve represents the derivative difference between the working current decrease curve I(t) and the mapped life curve at the same time point, that is, it represents the "changing trend" of the working current decrease curve I(t) and the degree of difference between the "changing trend" of the mapped life curve. The degree of difference between the two "changing trends" can represent the similarity between the working current decrease curve I(t) and the mapped life curve. Specifically, the smaller the difference between the "changing trends" at a certain time, the greater the similarity between the working current decrease curve I(t) and the mapped life curve at that point. In step S402B04A, the position of the minimum value in the third derivative curve is the position where the similarity between the working current drop curve I(t) and the mapped life curve is the greatest, that is, the position where the degree of synchronization between the working current drop curve I(t) and the mapped life curve is the highest. The moment corresponding to this position is used as the cut-off moment, which is conducive to making the change in the working current flowing through the switching device tend to be synchronized with the change in the remaining life of the switching device, which is conducive to maintaining the actual service life of the switching device within the design, production and maintenance plan of the switching device, thereby making it easier to plan the maintenance or replacement of the switching device, and reduce the consumption caused by improper use of the switching device while ensuring the safety of the electric vehicle.

[0095] When executing step S402B, that is, taking the time corresponding to the position where the working current drop curve has the greatest similarity with the life curve as the cut-off time, the following steps may be specifically performed:

[0096] S402B01B. Calculate the similarity of the mapped working current drop curve and the life curve in segments to obtain the similarity of each corresponding segment;

[0097] S402B02B. Determine the time corresponding to the maximum value among the similarities as the cutting time.

[0098] Steps S402B01B-S402B02B are a second execution method of step S402B.

[0099] The principle of step S402B01B is as follows Figure 5 As shown, the operating current drop curve and the life curve can be divided into segments corresponding to time subintervals such as T1, T2, ..., T10, according to their time intervals, and the segmented similarity calculation can be performed. For example, the similarity of the operating current drop curve and the life curve segments that are both within time subinterval T3 is calculated using the curve similarity algorithm to obtain the similarity corresponding to time subinterval T3.

[0100] In step S402B01B, assuming that the similarity corresponding to the time subinterval T5 is the maximum value among all similarities, a moment in the time subinterval T5 can be selected as the cut-off moment. Specifically, the midpoint of the time subinterval T5 can be selected as the cut-off moment.

[0101] In this embodiment, similar to the principle of executing steps S402B01A-S402B04A, the principle of executing steps S402B01B-S402B02B is: by calculating the similarity between the working current drop curve I(t) and the mapped life curve in segments, the position where the similarity between the working current drop curve I(t) and the mapped life curve is the greatest can be determined, that is, the position where the degree of synchronization between the working current drop curve I(t) and the mapped life curve is the highest. The moment corresponding to this position is used as the cut-off moment, which is conducive to making the change in the magnitude of the working current flowing through the switching device tend to be synchronized with the change in the remaining life of the switching device, which is conducive to maintaining the actual service life of the switching device within the design, production and maintenance plan of the switching device, thereby making it easier to plan the maintenance or replacement of the switching device, and reduce the consumption caused by improper use of the switching device while ensuring the safety of the electric vehicle.

[0102] In this embodiment, the power domain controller may further perform the following steps based on the execution of steps S1-S5:

[0103] S6. Obtaining the instantaneous current of the switching device at the time of disconnection;

[0104] S7. Compare the instantaneous current with the life curve;

[0105] S8. When the comparison result reaches the maintenance recommendation threshold, a maintenance prompt message is generated;

[0106] S9. Push the maintenance reminder information to the user terminal and / or server.

[0107] In step S6, the power domain controller detects the magnitude of the instantaneous current of the switching device at the moment of disconnection and records it.

[0108] In step S7, the power domain controller queries the life corresponding to the instantaneous current in the life curve (indicating the total life that can be used since installation), and then subtracts the service life of the switching device to determine the remaining service life of the switching device, and uses the remaining service life as the comparison result.

[0109] In step S8, the power domain controller reads a pre-stored maintenance recommendation threshold and compares it with the remaining service life. The maintenance recommendation threshold can determine the remaining service life. For example, if the remaining service life is less than the maintenance recommendation threshold, it can be determined that the remaining service life is too low, and the power domain controller generates a maintenance reminder message. The maintenance reminder message can include a message prompting maintenance or replacement of the switching device, as well as information about the instantaneous current.

[0110] In step S9, refer to Figure 1 The power domain controller pushes maintenance reminder information to the user terminal and / or server through the TSU and RTM. The user terminal can be a mobile phone or other terminal held by the electric vehicle owner, and the server can be a device set up by the electric vehicle manufacturer or service provider.

[0111] By executing steps S6-S9 to generate and push maintenance reminder information, the actual working information of the switching device can be recorded, and the owner or professional maintenance personnel can be notified when the remaining service life of the switching device is too low, which is conducive to tracking the life of the switching device, performing maintenance in a timely manner, and ensuring the safe use of the electric vehicle.

[0112] A computer program that executes the method for controlling the disconnection of the electric vehicle power battery switch in this embodiment can be written and written into a computer device or storage medium. When the computer program is read out and run, the method for controlling the disconnection of the electric vehicle power battery switch in this embodiment is executed, thereby achieving the same technical effect as the method for controlling the disconnection of the electric vehicle power battery switch in the embodiment.

[0113] It should be noted that, unless otherwise specified, when a feature is referred to as being "fixed" or "connected" to another feature, it may be directly fixed or connected to the other feature, or it may be indirectly fixed or connected to the other feature. In addition, the descriptions of up, down, left, right, etc. used in this disclosure are only relative to the relative positional relationships of the components of the present disclosure in the accompanying drawings. The singular forms of "a", "" and "the" used in this disclosure are also intended to include the plural forms, unless the context clearly indicates otherwise. In addition, unless otherwise defined, all technical and scientific terms used in this embodiment have the same meaning as those generally understood by those skilled in the art. The terms used in the specification of this embodiment are only for describing specific embodiments and are not intended to limit the invention. The term "and / or" used in this embodiment includes any combination of one or more related listed items.

[0114] It should be understood that, although the present disclosure may adopt the term first, second, third etc. to describe various elements, these elements should not be limited to these terms.These terms are only used to distinguish the elements of the same type from each other.For example, without departing from the scope of the present disclosure, the first element may also be referred to as the second element, and similarly, the second element may also be referred to as the first element.The use of any and all examples or exemplary language ("for example", "such as" etc.) provided by the present embodiment is only intended to better illustrate embodiments of the present invention, and unless otherwise required, the scope of the present invention will not be limited.

[0115] It should be appreciated that embodiments of the present invention can be implemented or practiced by computer hardware, a combination of hardware and software, or by computer instructions stored in a non-transitory computer-readable memory. The methods can be implemented in a computer program using standard programming techniques - including a non-transitory computer-readable storage medium configured with a computer program, wherein the storage medium so configured causes the computer to operate in a specific and predefined manner - according to the methods and figures described in the specific embodiments. Each program can be implemented in a high-level procedural or object-oriented programming language to communicate with the computer system. However, if desired, the program can be implemented in assembly or machine language. In any case, the language can be a compiled or interpreted language. In addition, the program can be run on a programmed application-specific integrated circuit for this purpose.

[0116] In addition, the operations of the processes described in this embodiment may be performed in any suitable order, unless otherwise indicated in this embodiment or otherwise clearly contradicted by the context. The processes described in this embodiment (or variations and / or combinations thereof) may be performed under the control of one or more computer systems configured with executable instructions, and may be implemented as code (e.g., executable instructions, one or more computer programs, or one or more applications) that is executed collectively on one or more processors, by hardware, or a combination thereof. A computer program includes multiple instructions that can be executed by one or more processors.

[0117] Furthermore, the method can be implemented in any type of computing platform that is operably connected to a suitable computer, including but not limited to a personal computer, a minicomputer, a mainframe, a workstation, a network or distributed computing environment, a separate or integrated computer platform, or in communication with a charged particle tool or other imaging device, etc. Various aspects of the present invention can be implemented as machine-readable code stored on a non-transitory storage medium or device, whether removable or integrated into a computing platform, such as a hard disk, an optical read and / or write storage medium, RAM, ROM, etc., so that it can be read by a programmable computer, and when the storage medium or device is read by the computer, it can be used to configure and operate the computer to perform the process described herein. In addition, the machine-readable code, or portions thereof, can be transmitted over a wired or wireless network. When such media includes instructions or programs that implement the above steps in conjunction with a microprocessor or other data processor, the invention of this embodiment includes these and other different types of non-transitory computer-readable storage media. When programmed according to the methods and techniques of the present invention, the present invention also includes the computer itself.

[0118] The computer program can be applied to input data to perform the functions of the present embodiment, thereby converting the input data to generate output data that is stored in a non-volatile memory. The output information can also be applied to one or more output devices such as a display. In a preferred embodiment of the present invention, the converted data represents a physical and tangible object, including a specific visual depiction of the physical and tangible object produced on the display.

[0119] The above are merely preferred embodiments of the present invention. The present invention is not limited to the aforementioned embodiments. As long as the technical effects of the present invention are achieved by the same means, any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention shall be included within the scope of protection of the present invention. Within the scope of protection of the present invention, various modifications and variations of the technical solutions and / or implementation methods may be made.

Claims

1. A method for controlling the disconnection of a power battery switch of an electric vehicle, characterized in that: The electric vehicle power battery switch cut-off control method includes: Identify the fault level of electric vehicles; According to the fault level, a corresponding operating current drop curve is matched; the operating current drop curve is used to represent the corresponding relationship between the operating current of the electric vehicle and time when adapted to the fault level; Obtaining a life curve of a switching device of a power battery of an electric vehicle; the life curve is used to represent a corresponding relationship between the off current and the life of the switching device; determining a cut-off time according to the operating current drop curve and the life curve; At the turn-off timing, the switching device is turned off.

2. The method for controlling the disconnection of a power battery switch of an electric vehicle according to claim 1, characterized in that: Matching a corresponding operating current drop curve according to the fault level includes: When the fault level is the first level, the working current drop curve is set to When the fault level is the second level, the operating current drop curve is set to When the fault level is the third level, the operating current drop curve is set to be in the form of I(t)=kt+I0; Among them, the fault severity represented by the first level, second level and third level decreases in sequence, I represents current, t represents time, U represents the bus voltage which is a constant, R1(t) represents the equivalent internal resistance of the electric vehicle's motor that changes with time in the ASC active short-circuit mode, R2(t) represents the equivalent internal resistance of the electric vehicle's high-voltage accessories that changes with time in the ASC active short-circuit mode, R3 represents the internal resistance of the power battery which is a constant, I1 represents the zero-torque point offset consumption current of the electric vehicle's motor, U(t) represents the bus voltage that changes with time in the zero-torque mode of the electric vehicle's motor, and k and I0 represent constant coefficients.

3. The method for controlling the disconnection of a power battery switch of an electric vehicle according to claim 1, characterized in that: The determining of the cut-off time according to the operating current drop curve and the life curve includes: Determining a safe cut-off current value according to the life curve; According to the working current drop curve, the time corresponding to the safety cut-off current value is queried as the cut-off moment.

4. The method for controlling the disconnection of a power battery switch of an electric vehicle according to claim 1, characterized in that: The determining of the cut-off time according to the operating current drop curve and the life curve includes: Mapping the operating current drop curve and the life curve to the same coordinate system; The time corresponding to the position where the similarity between the operating current drop curve and the life curve is the greatest is used as the cut-off moment.

5. The method for controlling the disconnection of a power battery switch of an electric vehicle according to claim 4, characterized in that: The time corresponding to the position where the similarity between the working current drop curve and the life curve is the greatest as the cut-off time includes: Performing a derivative operation of current with respect to time or a derivative operation of time with respect to current on the mapped working current drop curve to obtain a first derivative curve; Performing a derivative operation of current with respect to time or a derivative operation of time with respect to current on the mapped life curve to obtain a second derivative curve; Calculating the difference between the first derivative curve and the second derivative curve at corresponding points to obtain a third derivative curve; The time corresponding to the minimum value in the third derivative curve is determined as the cut-off time.

6. The method for controlling the disconnection of a power battery switch of an electric vehicle according to claim 4, characterized in that: The time corresponding to the position where the similarity between the working current drop curve and the life curve is the greatest as the cut-off time includes: Performing segmented similarity calculation on the mapped working current drop curve and the life curve to obtain similarity of each corresponding segment; The time corresponding to the maximum value among the similarities is determined as the cutting time.

7. The method for controlling the disconnection of a power battery switch of an electric vehicle according to any one of claims 1 to 6, characterized in that: The electric vehicle power battery switch cut-off control method further includes: Obtaining the instantaneous current of the switching device at the cut-off moment; comparing the instantaneous current with the life curve; When the comparison result reaches the maintenance recommendation threshold, a maintenance prompt message is generated.

8. The method for controlling the disconnection of a power battery switch of an electric vehicle according to claim 7, characterized in that: The electric vehicle power battery switch cut-off control method further includes: The maintenance prompt information is pushed to the user terminal and / or server.

9. A computer device, characterized in that: The invention comprises a memory and a processor, wherein the memory is used to store at least one program, and the processor is used to load at least one program to execute the electric vehicle power battery switch cut-off control method according to any one of claims 1 to 8.

10. A computer-readable storage medium storing a program executable by a processor, characterized in that: The program executable by the processor is used to execute the cut-off control method of the electric vehicle power battery switch according to any one of claims 1 to 8 when executed by the processor.

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