Patent Publication Number: US-2023152392-A1

Title: Fuse life expectancy prediction device for electric vehicle battery and prediction method thereof

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     The present application claims priority to Korean Patent Application No. 10-2021-0159436, filed Nov. 18, 2021, the entire contents of which is incorporated herein for all purposes by this reference. 
     BACKGROUND 
     Field 
     The present disclosure relates to a device and method for predicting a life expectancy of a fuse used in an electric vehicle battery. 
     Description of the Related Art 
     An electric vehicle refers to a vehicle using a battery engine that operates with electrical energy output from a battery. Such an electric vehicle has advantages of emitting no exhaust gas and being very quiet because it employs a chargeable and dischargeable battery as a main power source. 
     In the electric vehicle, a fuse is provided in a battery circuit and serves to protect the battery circuit from a short-circuit current when the circuit is short circuited in the abnormal state. The durability of the fuse is affected depending on how much and how long the current has passed in the fuse. In general, the more and the longer the current flows in the fuse, the lower the performance of the fuse is. In other words, the performance of the fuse is degraded with an increase in the number of times and time that a large amount of current flows in the fuse. 
     When the performance of the fuse is degraded, the fuse may blow out even in a normal current region where the battery circuit normally operates. In other words, the fuse, of which the performance is degraded, may blow out and interfere with the normal operation of the electric vehicle even though the battery circuit is not in an overcurrent. 
     To increase the durability of the fuse, if the fuse is designed to a superior specification, costs may increase significantly and the fuse may rather fall short of its duty because it does not work even in the overcurrent where the fuse should blow out to cut off the overcurrent. 
     Matters described as the related art are provided merely for promoting understanding for the background of the disclosure, and should not be taken as the prior art already known to a person having ordinary knowledge in the art. 
     SUMMARY 
     The disclosure is to provide a device and method for predicting a life expectancy of a fused formed in a battery circuit of an electric vehicle. 
     According to an embodiment of the disclosure, disclosed is a device for predicting a life expectancy of a fuse for a battery of an electric vehicle, the device including a sensor configured to generate and output current information about current flowing in the fuse, a processor, and a memory connected to the processor and configured to store a preset lookup table. The memory is storing program instructions which are executable by the processor to generate fuse-life expectancy information corresponding to the fuse based on the lookup table and time corresponding to an excess when the current information exceeds a preset threshold. 
     According to an embodiment, when the current information is driving current information, the memory may be configured to store program instructions for generating the fuse-life expectancy information based on a preset method by measuring a peak current and a peak time corresponding to the driving current information when the driving current information exceeds a preset driving threshold value, and the threshold value may be the driving threshold value. 
     According to an embodiment, the memory may be configured to store program instructions for cumulatively measuring the peak current and the peak time until the driving current information is lower than or equal to the driving threshold value, and generating the fuse-life expectancy information by looking up information corresponding to the cumulatively measured peak current and peak time from the lookup table. 
     According to an embodiment, when the current information is quick-charging current information, the memory may be configured to store program instructions for generating a quick-charging absolute current value corresponding to the quick-charging current information, and generating the fuse-life expectancy information based on a preset method by measuring a quick-charging current information and charging time when the quick-charging absolute current value exceeds a preset quick-charging threshold value, and the threshold value may be the quick-charging absolute current value. 
     According to an embodiment, the memory may be configured to store program instructions for cumulatively measuring the quick-charging current information and the charging time until the quick charging is completed, and generating the fuse-life expectancy information by looking up information corresponding to the cumulatively measured quick-charging current information and charging time from the lookup table. 
     According to an embodiment, the memory may be configured to further store program instructions for outputting a preset warning when the fuse-life expectancy information is lower than or equal to a preset warning reference. 
     According to an embodiment, the memory may be configured to store program instructions to detect a warning level of the fuse-life expectancy information, and output a warning corresponding to the warning level. 
     According to another embodiment of the disclosure, disclosed is a method of predicting a life expectancy of a fuse used for a battery of an electric vehicle in the fuse-life expectancy prediction device provided vehicle, the method including generating information about current flowing in the fuse, comparing the current information with a preset threshold value, and generating fuse-life expectancy information corresponding to the fuse based on a lookup table previously stored in a provided memory and time corresponding to an excess when the current information exceeds the threshold value. 
     According to an embodiment, when the current information is driving current information, the step of generating the fuse-life expectancy information may include: measuring a peak current and a peak time corresponding to the driving current information when the driving current information exceeds a preset driving threshold value; and generating the fuse-life expectancy information based on a preset method using the peak current and the peak time, and the threshold value may be the driving threshold value. 
     According to an embodiment, the step of generating the fuse-life expectancy information may include: cumulatively measuring the peak current and the peak time until the driving current information is lower than or equal to the driving threshold value; and generating the fuse-life expectancy information by looking up information corresponding to the cumulatively measured peak current and peak time from the lookup table. 
     According to an embodiment, when the current information is quick-charging current information, the step of generating the fuse-life expectancy information may include: generating a quick-charging absolute current value corresponding to the quick-charging current information; and generating the fuse-life expectancy information based on a preset method by measuring quick-charging current information and charging time when the quick-charging absolute current value exceeds a preset quick-charging threshold value, and the threshold value may be the quick-charging absolute current value. 
     According to an embodiment, the step of generating the fuse-life expectancy information may include: cumulatively measuring the quick-charging current information and the charging time until the quick charging is completed; and generating the fuse-life expectancy information by looking up information corresponding to the cumulatively measured quick-charging current information and charging time from the lookup table. 
     According to an embodiment, the fuse-life expectancy prediction method may further include outputting a preset warning when the fuse-life expectancy information is lower than or equal to a preset warning reference. 
     According to an embodiment, the outputting the warning may include: detecting a warning level of the fuse-life expectancy information; and outputting a warning corresponding to the warning level. 
    
    
     
       BRIEF DESCRIPTION OF THE FIGURES 
         FIG.  1    is a block diagram of a fuse-life expectancy prediction device according to an embodiment of the disclosure. 
         FIG.  2    is a diagram illustrating the shape of a fuse formed in an electric vehicle battery circuit. 
         FIG.  3    is a diagram illustrating the amount of current flowing in a fuse formed in an electric vehicle battery circuit. 
         FIG.  4    is a diagram showing simulation results of the exothermic characteristics of the fuse according to patterns of flowing current. 
         FIG.  5    is a diagram illustrating the amount of current to describe operations of the fuse-life expectancy prediction device according to an embodiment of the disclosure. 
         FIG.  6    is a diagram illustrating a lookup table to describe operations of a fuse-life expectancy prediction device according to an embodiment of the disclosure. 
         FIG.  7    is a diagram illustrating a lookup table according to an embodiment of the disclosure. 
         FIG.  8    is a flowchart of a fuse-life expectancy prediction method while driving an electric vehicle. 
         FIG.  9    is a flowchart of a fuse-life expectancy prediction method during the quick charging of an electric vehicle. 
     
    
    
     DETAILED DESCRIPTION 
     Exemplary embodiments according to the technical ideas of the disclosure are provided to more completely describe the technical ideas of the disclosure to a person having ordinary knowledge in the art, and the embodiments set forth herein may be changed in various different forms and should not be construed as limiting the scope of the disclosure. Rather, these embodiments are provided so that the disclosure will be thorough and complete, and will fully convey the technical ideas of the disclosure to those skilled in the art. 
     It will be understood that, although the terms ‘first,’ ‘second,’ etc. may be used herein to describe various members, regions, layers, sections and/or elements, theses members, components, regions, layers, sections and/or elements should not be limited by these terms. These terms do not denote any order, quantity or importance, but rather are only used to distinguish one member, region, section, or element from another member, region, section or elements. Thus, a first member, region, section or element to be discussed below could also be termed a second member, region, section or element without departing from the teachings of the technical ideas of the disclosure. For example, a first element may be referred to as a second element without deviating from the scope of the example embodiment, and similarly, the second element may also be referred to as the first component. 
     Further, an ‘electric vehicle’ needs to be construed as a concept including various types of vehicles such as a motor driving vehicle, a fuel cell vehicle, a hybrid vehicle, and the like to be driven by electric power. 
     Unless otherwise defined, all terms used herein include technical and scientific terms and have the same meaning as commonly understood by a person having ordinary knowledge in the art to which the concept of the disclosure pertains. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and will not be interpreted in an overly formal sense unless explicitly defined herein. 
     As used herein, the term ‘and/or’ includes any and all combinations of one or more of the mentioned elements. 
     Below, embodiments according to the technical ideas of the disclosure will be described in detail with reference to the accompanying drawings. 
       FIG.  1    is a block diagram of a fuse-life expectancy prediction device according to an embodiment of the disclosure. 
     A fuse-life expectancy prediction device  100  according to an embodiment of the disclosure may be mounted to the inside of an electric vehicle  10 . Referring to  FIG.  1   , the electric vehicle  10  may include the fuse-life expectancy prediction device  100  and a load  170 . Here, the fuse-life expectancy prediction device  100  of the electric vehicle  10  may include one or more batteries (a first battery  110 - 1  and a second battery  110 - 2 ) (hereinafter, referred to as  110 ), a fuse  120 , a sensor  130 , a switch  140 , a processor  150  and/or a memory  160 . 
     The load  170  may include a driving motor, various electronic components, and the like to powered from the battery  110 . The motor of the load  170  may receive the power from the battery  110  as a user controls an accelerator (not shown), and be actuated to drive the electric vehicle  10 . The electronic components (e.g., an air conditioner, an audio system, etc.) of the load  170  may be connected to the battery  110  as a user controls a switch, and be thus activated to implement a function desired by the user. 
     The battery  110  may be configured to supply the power needed for the foregoing operations of the electric vehicle  10 . The battery  110  may include any kind of battery, such as a lithium-ion battery, an iron phosphate battery, an all-solid-state battery, etc., as long as the battery can be used in the electronic vehicle  10 . 
     The fuse  120  may be formed in a circuit where the battery  110  is formed, and configured to protect the circuit of the battery  110  by cutting off an overcurrent more than an amount allowable for the circuit of the battery  110 . Details of the fuse  120  will be described with reference to  FIGS.  2  and  3   . 
     The sensor  130  may be provided in the circuit formed with the battery  110 , and configured to detect the amount of current flowing in the battery  110 . The sensor  130  may include an ammeter. Information about current detected by the sensor  130  (hereinafter referred to as ‘current information’) may be output to the processor  150 . 
     The switch  140  may be provided in the circuit provided with the battery  110 , and configured to switch over between connection and disconnection of the battery  110  and the load  170 . The switch  140  may be switched on and off under the control of the processor  150 . In other words, the processor  150  may turn on the switch  140  to connect the battery  110  and the load  170 , and turn off the switch  140  to disconnect the battery  110  and the load  170 . 
     The memory  160  refers to an element in which a lookup table, various threshold values, and program instructions are stored for operations of the fuse-life expectancy prediction device  100 , and includes a hard disk drive (HDD), a solid-state drive (SSD), and the like memory device. In particular, the memory  160  may be configured to store the program instructions for predicting the life expectancy of the fuse  120  based on the information about current flowing in the circuit of the battery  110  (i.e., the current information) and outputting information corresponding to prediction results under control of the processor  150 . 
     When receiving the current information from the sensor  130 , the processor  150  may predict the life expectancy of the fuse  120  by executing the lookup table, the threshold values and/or various program instructions stored in the memory  160 . Below, the functions of the program instructions for predicting the life expectancy of the fuse  120 , which are executed by the processor  150 , will be described in detail. 
     First, the fuse  120  will be additionally described with reference to  FIGS.  2  to  4   . 
       FIG.  2    is a diagram illustrating the shape of a fuse formed in a circuit of an electric vehicle battery circuit,  FIG.  3    is a diagram illustrating the amount of current flowing in the fuse formed in the circuit of the electric vehicle battery, and  FIG.  4    is a diagram showing simulation results of exothermic characteristics of the fuse according to patterns of flowing current. 
     Referring to  FIG.  2   , the fuse  120  may be made of an electric conductor such as copper. Further, the fuse  120  may include input and output terminals  210  and  220  to be physically and electrically connected to the circuit of the battery  110 , and one or more elements  230 . Current input to the input terminal  210  may diverge and flow through the elements  230 , and then converge to be output from the output terminals  220 . Ideally, the amount of input current to the input terminal  210  may be equal to the amount of output current from the output terminal  220 . 
     Each element  230  may be formed with a plurality of bodies  240 , and a narrow portion  250  connecting the bodies  240 .  FIG.  2    illustrates that two narrow portions are used for connecting the bodies  240 , but it is clear that the number of narrow portions  250  for connecting the bodies  240  may vary as necessary. 
     Referring to  FIG.  3   , an input current I p  input to the input terminal  210  may branch by two elements  230 . Therefore, a current input to the elements  310  and  320  (hereinafter, referred to as an ‘element current’) may correspond to half (I p /2) of the input current. Further, the element current may branch by two narrow portions  250 . Therefore, a current flowing in the narrow portion  250  (hereinafter referred to as a ‘narrow portion current’) may correspond to half (I p /4) of the element current. 
     Referring to  FIG.  4   , changes in temperature and exothermic characteristics in portions of the fuse  120  are shown when a current flowing in the fuse  120  is a direct current (DC) and when the current is a square wave. According to the types (the DC or the square wave) of current flowing in the fuse  120 , a degree of heat generated in the element  230  may be different. In particular, even though the square wave has the same average current level as the DC, heat generated in the narrow portion  250  is more largely varied in the square wave as difference between the highest current level and the lowest current level of the square wave becomes larger. The current flowing in the fuse  120  may correspond to the DC while the electric vehicle  10  is charging, but may correspond to the square wave while the electric vehicle  10  is driving. 
     Meanwhile, as shown in the following Expression 1, the life expectancy N of the fuse  120  may be decreased as the number of an average temperature T avg  and the number of repetitions of temperature change ΔT in the narrow portion  250  are increased (where, K, n and m are parameters related to the durability of the fuse  120 , which may be preset constants. 
     
       
         
           
             
               
                 
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     A relationship between the amount of current flowing in the fuse  120  and heat generated in the narrow portion  250  of the fuse  120  may be experimentally examined in advance. Therefore, the processor  150  may execute the program instructions stored in the memory  160  and generate information about the remaining life expectancy of the fuse  120  based on the current information. Below, it will be described with reference to  FIGS.  5  to  9    that the processor  150  generates the information about the life expectancy of the fuse  120 . 
       FIGS.  5  and  6    are diagrams illustrating the amount of current and a lookup table to describe operations of the fuse-life expectancy prediction device according to an embodiment of the disclosure, and  FIG.  7    is a diagram illustrating the lookup table according to an embodiment of the disclosure. 
     Referring to  FIG.  5   , the amounts of current flowing in the fuse  120  are as follows.
         200 A from 0 sec to 1000 sec   400 A from 1000 sec to 1100 sec   1600 A from 1100 sec to 1101 sec   800 A from 1101 sec to 1201 sec       

       FIG.  6    shows the lookup table where points are tabulated according to the amount of current flowing in the fuse  120  and time. Referring to the lookup table of  FIG.  6   , deduction points corresponding to the examples of  FIG.  5    are as follows.
         0 points from 0 sec to 1000 sec   10 points from 1000 sec to 1100 sec   100 points from 1100 sec to 1101 sec   500 points from 1101 sec to 1201 sec       

     When an initial value previously set in the fuse  120  is 1,000,000 points, information corresponding to the fuse  120  after the case of  FIG.  5    (hereinafter, referred to as ‘fuse-life expectancy information’) may be updated into ‘999,390’ (=1,000,000-0-10-100-500) points. Further, when the points to be deducted at quick charging are set to 10 points in advance and the electric vehicle undergoes quick charging after driving, the fuse-life expectancy information may be updated as deducted into 999,380 points. 
     The lookup table of  FIG.  6    may be previously stored in the memory  160 . Further,  FIG.  6    shows a simplified example, and the amount of current, time, and deduction points corresponding to the amount of current and the time (hereinafter, referred to as deduction information) may be stored in more detail like the lookup table shown in  FIG.  7   . 
     Below, it will be described in detail with reference to  FIGS.  8  and  9    that the processor  150  executes the program instructions of the memory  160  and generates the fuse-life expectancy information. 
       FIG.  8    is a flowchart of a fuse-life expectancy prediction method during driving of an electric vehicle, and  FIG.  9    is a flowchart of a fuse-life expectancy prediction method during quick charging of an electric vehicle. 
     The operations to be described below are performed by the processor  150  to execute the program instructions stored in the memory  160 , analyze information received from the sensor  130 , and generate the fuse-life expectancy information based on the analysis. However, the processor  150  for performing the operations is given by way of example for convenience of understanding and description. 
     First, referring to  FIG.  8   , at S 710 , the processor  150  may identify whether the electric vehicle  10  is driving. For example, the processor  150  may identify that the electric vehicle  10  is driving, based on an activated start of the electric vehicle  10 . 
     When it is identified that the electric vehicle  10  is not driving, the processor  150  may identify whether the electric vehicle  10  is in a quick charging mode at S 715 . For example, the processor  150  may recognize that the quick charging mode starts when a charging terminal of the electric vehicle  10  is connected to a commercial power source for charging. It will be described later with reference to  FIG.  9    that the processor  150  generates the fuse-life expectancy information in the quick charging mode. 
     When it is identified that the electric vehicle  10  is driving, the processor  150  may measure a driving current Ic at S 720 . For example, the processor  150  may regard the current information, which is received from the sensor  130  while the electric vehicle is driving, as the driving Ic. 
     At S 730 , the processor  150  may compare the driving current Ic and a preset threshold value (hereinafter, referred to as a ‘driving threshold value’ to be distinguishable from a threshold value of the quick charging mode. This is to identify whether driving current Ic is large enough to deteriorate the fuse  120 . 
     At S 740  and S 750 , the processor  150  may measure a peak current Ip and/or a peak time Tp corresponding to the driving current Ic when the driving current Ic exceeds the driving threshold value. While the electric vehicle  10  is driving, the value of current flowing in the fuse  120  may vary as time passes. Therefore, the processor  150  may cumulatively measure the peak current Ip and/or the peak time Tp of the driving current Ic. 
     For example, the processor  150  may measure the values of the driving current Ic (i.e., the peak current Ip) exceeding the driving threshold value, and excessive time (i.e., the peak time Tp). Then, the processor  150  calculates an average value or a root mean square (RMS) value during the peak time of the measured peak current when the driving current Ic is lower than or equal to the driving threshold value. 
     At S 760 , the processor  150  may look up the deduction information from the lookup table stored in the memory  160  based on the cumulatively measured peak current Ip and/or the peak time Tp. For example, it will be assumed that the lookup table stored in the memory  160  is equivalent to that shown in  FIG.  7   . Further, it will be assumed that the RMS value is 600 [A] and the peak time is 10 [sec] during the peak time of the peak current. In this case, the processor  150  may look up 1,000 [points] as the deduction information. 
     At S 770 , the processor  150  may update the fuse-life expectancy information by deducting the deduction information the fuse-life expectancy information stored in the memory  160 . 
     At S 780 , the processor  150  may identify whether a warning is necessary for the updated fuse-life expectancy information. For example, the processor  150  may identify that the warning is needed when the fuse-life expectancy information is lower than or equal to a preset warning threshold value (e.g., 100,000 [points]). 
     At S 790 , when it is identified that the warning is needed for the updated fuse-life expectancy information, the processor  150  may detect a level of the fuse-life expectancy information, and output a warning corresponding to the detected level. For example, let a first level range from 100,000 [points] to 50,000 [points], a second level range from 50,000 [points] to 20,000 [points], and a third level be lower than 20,000 [points]. In this case, the processor  150  detects the level of the updated fuse-life expectancy information. Then, the processor  150  outputs a warning corresponding to the detected level. Examples of warnings corresponding to the levels may be as follows.
         In the first level, the replacement of the fuse is imminent   In the second level, the fuse should be replaced   In the third level, no replacement of the fuse may cause the disconnection from the battery without any warning.       

     Meanwhile, referring to  FIG.  8   , at S 810 , the processor  150  may measure a quick charging current Iqc in the quick charging mode of the electric vehicle  10 . For example, the processor  150  may regard the current information received from the sensor  130  in the quick charging mode of the electric vehicle  10 , as the quick charging current Iqc. In the quick charging mode, a certain amount of current may flow in the fuse  120 . Of course, the amount of current flowing in the fuse  120  may vary sharply at the beginning of the quick charging, but it is merely a very short moment. Further, when the voltage of the battery  110  reaches a certain level or higher due to quick charging, the current flowing in the fuse  120  may vary. Even in this case, the current may change sharply for a short moment only at the beginning of change. Therefore, the processor  150  does not need to separately measure the peak voltage and the peak time in the quick charging mode unlike the driving mode. 
     In other words, at S 820 , the processor  150  may compare the quick charging current Iqc and a preset threshold value (hereinafter, referred to as ‘quick charging threshold value Iqc_n’). Further, at S 830 , the processor  150  measure the quick charging current and the charging time Tc when the quick charging current Iqc exceeds the quick charging threshold value Iqc_n. Thus, the processor  150  can identify how much and how long the current has flowed in the fuse  120  during the quick charging. 
     At S 840 , the processor  150  may look up the deduction information corresponding to the measured quick charging current and the charging time Tc from the previously-stored lookup table when the quick charging is completed. The subsequent operations are the same as those after S 760  described with reference to  FIG.  8   , and thus repetitive descriptions thereof will be avoided. 
     As described above, the fuse-life expectancy prediction device  100  according to an embodiment of the disclosure can predict the life expectancy of the fuse  120 , which is formed in the circuit of the battery  110  in the electric vehicle  10 , based on the amount and time of current flowing in the fuse  120 . Further, the fuse-life expectancy prediction device  100  according to an embodiment of the disclosure allows a user to replace the fuse before the fuse reaches the end of its life expectancy, thereby preventing problems that may occur as the fuse blows out in a normal operating situation. 
     According to the disclosure, there are provided a device and method for predicting the life expectancy of the fuse formed in the battery circuit of the electric vehicle. 
     Further, according to the disclosure, a user can replace the fuse before the fuse reaches the end of its life expectancy to prevent problems that may occur as the fuse blows out in a normal operating situation, and the fuse having not excessive but proper performance is used to keep the driving of the vehicle economical and safe. 
     Although a few embodiments of the disclosure have been described in detail, the disclosure is not limited to these embodiments and various changes and modifications can be made by a person having ordinary knowledge in the art without departing from the technical ideas and scope of the disclosure.