Electric vehicle charging safety detection method and device

Abstract

The present application discloses a method and device for detecting the charging safety of electric vehicles. The method obtains a standard charging curve by fitting multiple historical charging curves with the same rated voltage of the battery pack, compares the similarity between the real-time charging curve of each charging port and the standard charging curve, and determines the charging safety status of each charging port based on the similarity, thereby avoiding the problem of inaccurate detection results caused by continuous real-time monitoring of charging parameters and estimating charging safety based on the charging parameters in the related art. In addition, after determining the charging safety status of each charging port, a weight coefficient is calculated based on the distance from the charging port that is first determined to be abnormally charged, and the fire hazard status is estimated based on the weight coefficient, thereby confirming or eliminating the fire hazard of the electric vehicle.

Description

Technical Field

[0001] The present application relates to the technical field of electric vehicle charging data analysis, and in particular to a detection method and device for electric vehicle charging safety. Background Art

[0002] With the development of science and technology, the number of new energy vehicles is increasing, and the phenomenon of new energy vehicles, especially electric vehicles, catching fire is increasing. Among them, the rate of spontaneous combustion of vehicles during the charging process is relatively high. Charging usually occurs in the evening and late at night, and people cannot pay real-time attention to the situation of the charging station. In the prior art, the fire situation of electric bicycles at the charging station is judged by smoke sensors, visual detectors and temperature sensors. Although accurate and reliable, the deployment of a large number of sensors brings high costs, which is difficult for charging stations to bear. The existing detection technology uses a large number of external sensors to achieve detection and ignores the rapid changes in the voltage and current of the charging port of the electric bicycle when it catches fire. At the same time, it ignores the changes in the voltage and current of the adjacent charging ports when the fire spreads to the adjacent electric vehicles, that is, it ignores the information contained in the overall change and ignores the advantages of complementary perception of the information of each charging port. Summary of the invention

[0003] In view of this, the electric vehicle charging safety detection and device of the present application can accurately detect the charging safety status.

[0004] In a first aspect, the present application provides a method for detecting the charging safety of an electric vehicle, comprising:

[0005] Fitting a plurality of historical charging curves having the same rated voltage of the battery pack to obtain a standard charging curve, wherein the historical charging curve is defined as a charging curve with normal charging;

[0006] Comparing the similarity between the real-time charging curve of each charging port and the standard charging curve;

[0007] The charging safety status of each charging port is determined according to the similarity.

[0008] Optionally, a method for determining the multiple historical curves to be fitted is:

[0009] Collect historical charging curves that occur in a series of most adjacent time periods.

[0010] Optionally, multiple historical charging curves with the same battery pack rated voltage are fitted, including:

[0011] For multiple historical charging curves, obtain the current sequence value and voltage sequence value occurring in each time period respectively;

[0012] The current-time set consisting of the current sequence value and the time period corresponding to the current sequence value, and the voltage-time set consisting of the voltage sequence value and the time period corresponding to the voltage sequence value are fitted respectively to obtain a standard charging curve.

[0013] Optionally, comparing the similarity between the real-time charging curve of each charging port and the standard charging curve includes:

[0014] For the standard charging curve and the real-time charging curve of each charging port, obtain the current and voltage sequence values ​​occurring in each time period;

[0015] Determine the distance value between the current and voltage sequence values ​​of the standard charging curve and the current and voltage sequence values ​​of the real-time charging curve in the same time period respectively;

[0016] The similarity is determined based on the minimum value among multiple distance values.

[0017] Optionally, the similarity is determined according to the smallest of multiple distance values, which is expressed by the following formula:

[0018] ;

[0019] in, L min for The minimum distance value, L max is the maximum distance value, n is the number of historical charging curves.

[0020] Optionally, the method further comprises:

[0021] After determining the charging safety status of each charging port, after determining the charging safety status of each charging port, determining a weight coefficient according to distance information between each charging port and the charging port that is first determined to have abnormal charging;

[0022] A fire hazard condition is estimated based on the weight coefficient.

[0023] Optionally, the fire hazard condition is estimated and determined by the following formula,

[0024] ;

[0025] ;

[0026] ;

[0027] In the above formula, W is the weight coefficient, K is a sensitivity coefficient between 0 and 1. XRefers to the distance from the charging port that was first identified as charging abnormally. D Refers to the closest distance to the charging port that was first identified as having abnormal charging. P(x) is the charging safety status value, A Provide an estimate of the fire hazard situation.

[0028] In a second aspect, the present application provides a device for detecting the safety of electric vehicle charging, comprising:

[0029] A fitting module, used for fitting a plurality of historical charging curves having the same rated voltage of the battery pack to obtain a standard charging curve, wherein the historical charging curve is defined as a charging curve with normal charging;

[0030] A comparison module, used to compare the similarity between the real-time charging curve of each charging port and the standard charging curve;

[0031] A determination module is used to determine the charging safety status of each charging port according to the similarity.

[0032] In a third aspect, the present application provides an execution device, including a processor and a memory, wherein the processor is coupled to the memory;

[0033] The memory is used to store programs;

[0034] The processor is used to execute the program in the memory, so that the execution device executes the above method.

[0035] In the method disclosed in the present application, a plurality of historical charging curves having the same rated voltage of the battery pack are fitted to obtain a standard charging curve, the real-time charging curve of each charging port is compared with the standard charging curve for similarity, and the charging safety status of each charging port is determined based on the similarity, thereby avoiding the problem of inaccurate detection results caused by continuously monitoring the charging parameters in real time and estimating the charging safety based on the charging parameters in the related art. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] The technical solution and other beneficial effects of the present application will be made apparent by describing in detail the specific implementation methods of the present application in conjunction with the accompanying drawings.

[0037] Figure 1 An operational flow chart of detecting the safety of charging an electric vehicle provided by an exemplary embodiment is shown;

[0038] Figure 2 A block diagram showing a device for detecting the safety of charging an electric vehicle provided by an exemplary embodiment is shown;

[0039] Figure 3 A block diagram of the execution device provided by an exemplary embodiment is shown. DETAILED DESCRIPTION

[0040] In order to make the above-mentioned purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are described in detail below in conjunction with the accompanying drawings. In the following description, many specific details are set forth to facilitate a full understanding of the present application. However, the present application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without violating the connotation of the present application, so the present application is not limited by the specific embodiments disclosed below.

[0041] The terms "first", "second", etc. in the specification and claims of this application and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchangeable where appropriate, so that the embodiments described here can be implemented in an order other than that illustrated or described here. In addition, the terms "including" and "having" and any of their variations are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device that includes a series of steps or modules is not necessarily limited to those steps or modules clearly listed, but may include other steps or modules that are not clearly listed or inherent to these processes, methods, products or devices. The naming or numbering of steps in this application does not mean that the steps in the method flow must be executed in the time / logical sequence indicated by the naming or numbering. The process steps that have been named or numbered can change the execution order according to the technical purpose to be achieved, as long as the same or similar technical effects can be achieved. The division of units in this application is a logical division. There may be other division methods when it is implemented in actual applications. For example, multiple units can be combined or integrated into another system, or some features can be ignored or not executed. In addition, the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, and the indirect coupling or communication connection between units can be electrical or other similar forms, which are not limited in this application. In addition, the units or sub-units described as separate components may or may not be physically separated, may or may not be physical units, or may be distributed in multiple circuit units, and some or all of the units may be selected according to actual needs to achieve the purpose of the present application.

[0042] Please refer to Figure 1 , Figure 1 A flowchart of a method for detecting the charging safety of an electric vehicle provided by an exemplary embodiment is shown. It should be particularly noted that the electric vehicle to which this method is applicable is not limited to electric bicycles, but may also be electric motorcycles, electric tricycles, electric vehicles or other similar forms. For the convenience of explanation, the following descriptions are all based on electric bicycles, electric motorcycles or electric tricycles as examples.

[0043] This method is implemented through steps 102-106.

[0044] In step 102, a plurality of historical charging curves having the same rated voltage of the battery pack are fitted to obtain a standard charging curve, wherein the historical charging curve is defined as a charging curve with normal charging.

[0045] It is easy to understand that the "charging curve" mentioned in this article also refers to the charging power curve, that is, a curve with time as the horizontal axis and voltage and current as the dual vertical axes. The acquisition and collection of the charging curve can be from the mature commercial application of electric bicycle intelligent charging pile platforms, such as Beichen and Shankailaidian.

[0046] It is easy to understand that the rated voltage of the battery pack can be, for example, the well-known 48V, 60V, 72V, etc., among which 60V and 72V are usually for electric tricycles or electric motorcycles, and 48V is for national standard electric bicycles.

[0047] Taking the charging process of a lead-acid battery as an example, there are many ways to charge a lead-acid battery, and three-stage charging is the most common and widely used charging method. The three stages of three-stage charging refer to the constant current charging stage, the constant voltage charging stage, and the step-down floating charging stage (also called the trickle charging stage). At present, the three-stage charging generally uses an intelligent control charger, which can automatically switch the charging mode in three different charging stages.

[0048] As mentioned above, "the historical charging curve is defined as a normal charging curve". As for the defined operation, it belongs to mature existing technology and can be automatically detected and obtained by the platform for collecting charging curves, namely the electric bicycle intelligent charging pile platform. The technical principle of its implementation is based on the predetermined charging curve of three-stage charging, and the voltage and current levels in the actual charging curve that have obvious deviations from the three-stage charging curve are defined as abnormal charging, such as but not limited to the following situations:

[0049] A. The power is obviously too high in the step-down floating charging stage of the three-stage charging curve;

[0050] B. The overall trend of the actual charging curve does not follow the overall trend of the three-stage charging curve.

[0051] As an example, the method for determining the multiple historical curves to be fitted is:

[0052] Collect historical charging curves that occur in a series of most adjacent time periods.

[0053] Here, the specific level of the time period can be selected according to actual needs, such as 15s, 30s or 1min.

[0054] The historical charging curves occurring in the most adjacent time periods refer to a series of time periods corresponding to these historical charging curves with normal charging, which are arranged from earliest to latest without interruption. Specifically, taking the historical charging curve A1 occurring from 9:00:00 to 9:00:15 a.m., the historical charging curve A2 occurring from 9:00:16 to 9:00:30 a.m., the historical charging curve A3 occurring from 9:00:31 to 9:00:45 a.m., and the historical charging curve A4 occurring from 9:00:46 to 9:01:00 a.m. as examples, if the historical charging curve A2 is defined as abnormal charging, then the time period B1 from 9:00:00 to 9:00:15 a.m., the time period B3 from 9:00:31 to 9:00:45 a.m., and the time period B4 from 9:00:46 to 9:01:00 a.m. constitute a series of the most adjacent time periods; if the historical charging curves A1-A4 are all normal charging, then the time periods B1-B4 constitute a series of the most adjacent time periods.

[0055] By setting the time periods of the historical charging curve to be the most adjacent, data differences due to system stability caused by the time periods being too far apart in sequence are avoided.

[0056] In some exemplary implementations, fitting multiple historical charging curves having the same battery pack rated voltage includes:

[0057] For multiple historical charging curves, obtain the current sequence value and voltage sequence value occurring in each time period respectively;

[0058] The current-time set consisting of the current sequence value and the time period corresponding to the current sequence value, and the voltage-time set consisting of the voltage sequence value and the time period corresponding to the voltage sequence value are fitted respectively to obtain a standard charging curve.

[0059] As an actual fitting operation, it can be: mark multiple historical charging curves of corresponding voltage levels as k, k=1, 2, ..., n, n is a positive integer; first, collect n historical charging curves once every 15 seconds for discretization, assuming that t horizontal coordinates are collected, the corresponding vertical coordinates of voltage and current are and , i=1, 2, ..., t, t is a positive integer, b=1, 2, ..., n, n is a positive integer. Then use the formula and Get a sequence of t points, smooth the t points, and get the fitted historical charging curve, i.e., the standard charging curve. The standard charging curve is marked as Y .

[0060] In step 104, the similarity between the real-time charging curve of each charging port and the standard charging curve is compared.

[0061] As an exemplary implementation, comparing the similarity between the real-time charging curve of each charging port and the standard charging curve includes:

[0062] For the standard charging curve and the real-time charging curve of each charging port, obtain the current and voltage sequence values ​​occurring in each time period;

[0063] Determine the distance value between the current and voltage sequence values ​​of the standard charging curve and the current and voltage sequence values ​​of the real-time charging curve in the same time period respectively;

[0064] The similarity is determined based on the minimum value among multiple distance values.

[0065] In order to further understand the above similarity comparison process, in actual operation, firstly, the real-time charging curve of each charging port is calculated. X And standard charging curve Y Discretize, take a value every 15 seconds (or other time periods), and mark each point on the time axis as m, where m=1, 2, ..., n, and n is a positive integer. A series of horizontal coordinates are obtained: , the vertical axis is and point, A series of points is a sequence A , A series of points is a sequence B ;

[0066] Step SA4: The charging curve is nonlinear, so we use the following method to measure the real-time charging curve and the fitted historical charging curve Y Curve similarity of these two nonlinear curves First, create a n * n matrix M, matrix M Representation sequence A and sequence B The distance between each point , Represents A's i point and B's j The distance between the points, Then, through the formula and , Calculated and value; according to , Get the similarity.

[0067] Here, the similarity is determined based on the minimum and maximum of multiple distance values, which is expressed by the following formula:

[0068] ;

[0069] in, L min for The minimum distance value, L max is the maximum distance value, n is the number of historical charging curves.

[0070] In step 106, the charging safety status of each charging port is determined according to the similarity.

[0071] In order to facilitate further understanding of the above process of determining the charging safety status of each charging port based on the similarity, in actual operation, the charging port with a curve similarity greater than the threshold T is marked as a normal charging port, and the charging port with a curve similarity less than the threshold T is marked as an abnormal charging port; each charging port is combined and evaluated to determine whether the electric vehicle in the entire charging station is on fire. The threshold T can be freely set within 0 to 1 according to the requirements of system sensitivity.

[0072] As an exemplary implementation, the method further includes:

[0073] After determining the charging safety status of each charging port, determining a weight coefficient according to distance information between each charging port and the charging port that is first determined to have abnormal charging;

[0074] A fire hazard condition is estimated based on the weight coefficient.

[0075] It is worth adding that the distance information here includes the actual distance to the charging port that is first determined to have abnormal charging and the closest distance to the charging port that is first determined to have abnormal charging.

[0076] To further understand the estimated fire hazard, the following formula can be used to determine:

[0077] ;

[0078] ;

[0079] ;

[0080] In the above formula, W is the weight coefficient, K is a sensitivity coefficient between 0 and 1. X Refers to the distance from the charging port that was first identified as charging abnormally.D Refers to the closest distance to the charging port that was first identified as having abnormal charging. P(x) is the charging safety status value, A Provide an estimate of the fire hazard situation.

[0081] It should be easy to think that when A When the value exceeds the system setting value, it is considered that there is an electric vehicle fire in the charging station. A When the value exceeds the system setting value, the control module automatically cuts off the power to all electric bicycles judged to be abnormal and sends an alarm to the outside world.

[0082] Please refer to Figure 2 , which shows a block diagram of the electric vehicle charging safety detection device provided by the present application. The device 200 includes:

[0083] A fitting module 202, for fitting a plurality of historical charging curves having the same rated voltage of the battery pack to obtain a standard charging curve, wherein the historical charging curve is defined as a charging curve with normal charging;

[0084] A comparison module 204, used to compare the similarity between the real-time charging curve of each charging port and the standard charging curve;

[0085] The determination module 206 is used to determine the charging safety status of each charging port according to the similarity.

[0086] Since the above methods have been discussed in detail, the specific implementation of the above modules will not be repeated here.

[0087] Next, an execution device provided by an embodiment of the present application is introduced. Figure 3 , Figure 3 This is a schematic diagram of a structure of an execution device provided in an embodiment of the present application. The execution device 300 can be specifically manifested as an autonomous driving vehicle, a mobile phone, a tablet, a laptop computer, a desktop computer, a monitoring data processing device, etc., which is not limited here. Figure 1 The functions of the execution device in the corresponding embodiment. Specifically, the execution device 300 includes: a receiver 301, a transmitter 302, a processor 303 and a memory 304 (wherein the number of the processor 303 in the execution device 300 can be one or more, Figure 3 In the example of FIG. 3 , the processor 303 may include an application processor 3031 and a communication processor 3032. In some embodiments of the present application, the receiver 301, the transmitter 302, the processor 303 and the memory 304 may be connected via a bus or other means.

[0088] The memory 304 may include a read-only memory and a random access memory, and provides instructions and data to the processor 303. A portion of the memory 304 may also include a non-volatile random access memory (NVRAM). The memory 304 stores processor and operation instructions, executable modules or data structures, or subsets thereof, or extended sets thereof, wherein the operation instructions may include various operation instructions for implementing various operations.

[0089] The processor 303 controls the operation of the execution device. In a specific application, the various components of the execution device are coupled together through a bus system, wherein the bus system includes not only a data bus but also a power bus, a control bus, and a status signal bus, etc. However, for the sake of clarity, various buses are referred to as bus systems in the figure.

[0090] The method disclosed in the above embodiment of the present application can be applied to the processor 303, or implemented by the processor 303. The processor 303 can be an integrated circuit chip with signal processing capabilities. In the implementation process, each step of the above method can be completed by the hardware integrated logic circuit or software instructions in the processor 303. The above processor 303 can be a general-purpose processor, a digital signal processor (digital signal processing, DSP), a microprocessor or a microcontroller, and can further include an application specific integrated circuit (application specific integrated circuit, ASIC), a field programmable gate array (field-programmable gate array, FPGA) or other programmable logic devices, discrete gates or transistor logic devices, discrete hardware components. The processor 303 can implement or execute the various methods, steps and logic block diagrams disclosed in the embodiments of the present application. The general processor can be a microprocessor or the processor can also be any conventional processor, etc. The steps of the method disclosed in the embodiment of the present application can be directly embodied as a hardware decoding processor to be executed, or the hardware and software modules in the decoding processor can be combined and executed. The software module may be located in a storage medium mature in the art, such as a random access memory, a flash memory, a read-only memory, a programmable read-only memory, or an electrically erasable programmable memory, a register, etc. The storage medium is located in the memory 304, and the processor 303 reads the information in the memory 304 and completes the steps of the above method in combination with its hardware.

[0091] The receiver 301 can be used to receive inputted digital or symbol information, and generate signal input related to the relevant settings and function control of the execution device. The transmitter 302 can be used to output the digital or symbol information through the first interface; the transmitter 302 can also be used to send instructions to the disk group through the first interface to modify the data in the disk group; the transmitter 302 can also include a display device such as a display screen.

[0092] In the embodiment of the present application, the processor 303 is used to execute Figure 1 The specific manner in which the application processor 3031 in the processor 303 performs the above steps is the same as that in the present application. Figure 1 The corresponding method embodiments are based on the same concept, and the technical effects they bring are the same as those in this application. Figure 1 The corresponding method embodiments are the same. For specific contents, please refer to the description in the method embodiments shown above in this application, which will not be repeated here.

[0093] The above is only a preferred specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any changes or substitutions that can be easily conceived by any technician familiar with the technical field within the technical scope disclosed in the present application should be covered within the protection scope of the present application.

Claims

1. A method for detecting the safety of electric vehicle charging, characterized in that: include: Fitting a plurality of historical charging curves having the same rated voltage of the battery pack to obtain a standard charging curve, wherein the historical charging curve is defined as a charging curve with normal charging; Comparing the similarity between the real-time charging curve of each charging port and the standard charging curve; Determining a charging safety status of each charging port according to the similarity; The method further comprises: After determining the charging safety status of each charging port, determining a weight coefficient according to distance information between each charging port and the charging port that is first determined to have abnormal charging; estimating a fire hazard condition based on the weight coefficient; The estimated fire hazard condition is determined by the following formula: ； ； ； In the above formula, W is the weight coefficient, K is a sensitivity coefficient between 0 and 1. X Refers to the distance from the charging port that was first identified as charging abnormally. D Refers to the closest distance to the charging port that was first identified as having abnormal charging. P(x) is the charging safety status value, A Provide an estimate of the fire hazard situation.

2. The method according to claim 1, characterized in that The method for determining the multiple historical charging curves to be fitted is: Collect historical charging curves that occur in a series of most adjacent time periods.

3. The method according to claim 1, characterized in that Fit multiple historical charging curves with the same battery pack rated voltage, including: For multiple historical charging curves, obtain the current sequence value and voltage sequence value occurring in each time period respectively; The current-time set consisting of the current sequence value and the time period corresponding to the current sequence value, and the voltage-time set consisting of the voltage sequence value and the time period corresponding to the voltage sequence value are fitted respectively to obtain a standard charging curve.

4. The method according to claim 1, characterized in that Comparing the similarity between the real-time charging curve of each charging port and the standard charging curve includes: For the standard charging curve and the real-time charging curve of each charging port, obtain the current and voltage sequence values ​​occurring in each time period; Determine the distance value between the current and voltage sequence values ​​of the standard charging curve and the current and voltage sequence values ​​of the real-time charging curve in the same time period respectively; The similarity is determined based on the minimum and maximum values ​​of multiple distance values.

5. The method according to claim 4, characterized in that The similarity is determined based on the minimum and maximum values ​​of multiple distance values, which can be expressed by the following formula: ； in, is the similarity, L min for The minimum distance value, L max The maximum distance value.

6. A detection device for electric vehicle charging safety, characterized in that: The electric vehicle charging safety detection device is used to execute the electric vehicle charging safety detection method according to any one of claims 1 to 5, comprising: A fitting module, used for fitting a plurality of historical charging curves having the same rated voltage of the battery pack to obtain a standard charging curve, wherein the historical charging curve is defined as a charging curve with normal charging; A comparison module, used to compare the similarity between the real-time charging curve of each charging port and the standard charging curve; A determination module is used to determine the charging safety status of each charging port according to the similarity.

7. A computer-readable storage medium, characterized in that: The invention comprises a program, which, when being executed on a computer, causes the computer to execute the method according to any one of claims 1 to 5.

8. An execution device, characterized in that: comprising a processor and a memory, wherein the processor is coupled to the memory; The memory is used to store programs; The processor is configured to execute the program in the memory so that the execution device executes the method according to any one of claims 1 to 5.

Images